Process for producing fine polymer particle

Background to the invention

Microspheric, micro-sized polymeric spheres are used as cosmetic additives, bases for various chemical materials, spacers, chromatographic column fillings, light scattering agents, porosity enhancers, weight reducing agents, anti-blocking agents, paper surface modification means, etc.

In particular, the microspheres of cross-linked hydrophilic polymer can be used as hydrogel microparticles that are useful as cosmetic additives, foundations, porosity enhancers, weight-reducing agents or agents for modifying the surface of recording paper.

The production of polymer particles by suspension polymerization is widely made widely, and in particular the production of cross-linked hydrophilic polymer particles by phase suspension polymerization is also well known. Conventional techniques for the preparation of cross-linked hydrophilic polymer particles by suspension phase inversion polymerization employ a method in which a copolymer with 8 or more carbon atoms of the acrylic and (meth) acrylic acid ester has a polar group, such as a carboxyl group, is used as a dispersing agent ( Patent publications 1 and 2), a method in which a macromonomer based on polyethylene oxide is used (Patent Publication 3), a method in which silicone compounds are used (Patent Publication 4), etc.

However, in these conventional techniques, problems such as the stability of the dispersion of polymer particles during polymerization or after polymerization, which is insufficient, the particle size of the resulting polymer particles is heterogeneous and the hydrophilicity of the resulting polymer particles is degraded. In particular, when the hydrophilic cross-linkable polymer particles are prepared by suspension phase polymerization during the increasing proportion of the vinyl-based multifunctional monomer used, the polymerization stability is significantly reduced and problems such as particle aggregation, degradation of the polymer particles obtained. and reducing productivity can easily occur.

<td>(Publication</td><td>patent</td><td>1)</td><td>JP-A-1-213307 (JP-A means</td><td>Japanese</td>

<td colspan="2">unexplored publication</td><td colspan="2">patent application)</td><td></td>

<td>(Publication</td><td>patent</td><td>2)</td><td>JP-A-11-60616</td><td></td>

<td>(Publication</td><td>patent</td><td>3)</td><td>JP-A-9-143210</td><td></td>

<td>(Publication</td><td>patent</td><td>4)</td><td>JP-A-2003-34725</td><td></td>

<td>(Publication</td><td>patent</td><td>5)</td><td>JP-A-2004-149569</td><td></td>

<td>(Publication</td><td>patent</td><td>6)</td><td>International publication</td><td>patent</td>

<td>WO 01/04163</td><td></td><td></td><td></td><td></td>

<td>(Publication</td><td>patent</td><td>7)</td><td>JP-A-2000-35697</td><td></td>

The object of the invention is to provide a process for suspension polymerization with phase inversion with high productivity, high quality polymer microparticles having uniform dimensions in the order of a few μm to several tens μm with good dispersion stability without causing aggregation, etc. between particles.

In particular, this invention provides a suspension polymerization method that can be readily used to produce high quality, high quality polymeric microparticles with uniform particle sizes while maintaining suspension stability with high polymerization stability even when microparticle crosslinked hydrophilic polymer with high degree of crosslinking is produced.

The present inventors have engaged in intensive research measures to achieve the above objectives. As a result, it was found that during the production of polymer microparticles by suspension polymerization of a vinyl-based monomer, if the suspension polymerization is carried out using a special macromonomer as a dispersion stabilizer, i.e. using a dispersion-stabilizing macromonomer which is based on vinyl-derived monomer polymer having at least one terminal group being an unsaturated, radically polymerizable, high quality spherical polymer microparticles having a homogeneous particle size in the range of a few μm to several tenths of μm can be obtained with high productivity while maintaining good dispersion stability and polymerization stability,

Moreover, the present inventors have found that a special macromonomer is particularly effective as a dispersion stabilizer when hydrophilic polymer microparticles are produced by suspension polymerization with phase inversion, especially microparticles of a hydrophilic crosslinked polymer, and when suspension polymerization with phase inversion of a vinyl-based hydrophilic monomer. is carried out using a special macromonomer as a dispersion stabilizer, even when producing a cross-linked hydrophilic polymer with a high degree of cross-linking by using a large amount of multifunctional vinyl-based monomer, high-quality hydrophilic polymer microparticles cross-lined with relatively homogeneous particle size can be obtained with good productivity .when the good dispersion stabilizer and polymerization stability are maintained, without causing aggregation of the polymer particles, formation of clusters of these, adhesion of polymer particles to the polymerization apparatus, etc.

Furthermore, the present inventors have discovered that, depending on the macromonomer used as dispersion stabilizer during suspension polymerization, and in particular phase suspension polymerization, a macromonomer having an α-substituted vinyl group represented by the formula H2C = C (X) - (in formula X is a monovalent polar group) as the termination of a vinyl-based monomer derivative obtained by radical polymerization of a vinyl-based monomer at 150 ° C to 350 ° C and / or a macromonomer having a (meth) acryloyl group as the termination of a polymer derived from a monomer-based monomer vinyl are suitable because of their excellent function as a dispersion stabilizer,the preferred macromonomer has a weight average molecular weight of 1000 to 30,000 and the macromonomer preferably has both hydrophilic vinyl-based monomer derived constituent units and vinyl-based monomer-derived derivatives based on which the hydrophobic vinyl-derived monomer derived component is preferred as a constituent unit a derivative of alkyl esters with 8 or more carbon atoms and (meth) acrylic acid, whereas hydrophilic vinyl-based monomer derived constituent units are preferred as a component derived from a vinyl-based monomer having a carboxyl group, the present invention has been completed based on these findings.

Thus, the present invention is:

(1) a process for the production of polymer microparticles by suspension polymerization with a phase inversion of the vinyl-based monomer, where the polymerization in suspension of the vinyl-based monomer is carried out using a macromonomer having unsaturated radical-polymerizable groups as the termination of the vinyl-based monomer-derived polymer as stabilizer dispersion.

In addition, the present invention is (2) a production process according to (1) above, wherein the macromonomer, used as a dispersion stabilizer, is a macromonomer having vinyl α-substituted groups as the termini of a vinyl-based monomer derived polymer, shown as formula (I) below, which is obtained by radical polymerization at 150 ° C to 350 ° C of a vinyl-based monomer, the vinyl-based monomer is the substrate for the production of the macromonomer;

h₂c = C-- _(AND)

X (in the formula, X is a monovalent polar group).

Moreover, the present invention is (3) a production process according to (1) or (2) above, wherein the macromonomer, used as a dispersion stabilizer, is a macromonomer having a (meth) acryloyl group as the termination of the vinyl-based monomer derived polymer;

(4) a production method according to any one of (1) to (3) above, wherein the macromonomer, used as a dispersion stabilizer, has a weight average molecular weight of from 1000 to 30,000;

(5) a production method according to any one of (1) to (4) above, wherein the macromonomer, used as a dispersion stabilizer, is a macromonomer having a hydrophobic vinyl-based monomer derived component and a hydrophilic vinyl-based constituent;

(6) a production method according to (5) above, wherein at least a few of the hydrophobic vinyl-based monomer derived constituent macromonomer are derived from an alkyl ester with 8 carbons or more and (meth) acrylic acid; and (7) a production method according to (5) or (6) above, wherein at least a number of hydrophilic vinyl-based monomer derivative units are based on a vinyl macromonomer is a derivative of a vinyl-based monomer having a carboxyl group, and the macromonomer has sub-base monomer derived component units. on a vinyl having carboxylic groups in a proportion of 10 to 40% by mass of the total weight of the constituent units forming the macromonomer.

The present invention is also (8) a production process according to any one of (1) to (7) above, wherein the polymer microparticles produced by suspension polymerization have an average particle size of 2 to 100 μη;

(9) a production process according to any one of (1) to (8) above, wherein the crosslinked polymer microparticles are produced using a vinyl-based monomer for suspension polymerization of a monofunctional vinyl-based monomer and a multifunctional vinyl-based monomer in a molar ratio of monofunctional monomer based on vinyl: a multifunctional vinyl-based monomer = 100: 0.1 to 100;

(10) a production process according to any one of (1) to (9) above, wherein at least a number of vinyl-based monomers used in suspension polymerization is a vinyl-based monomer having polar groups selected from a carboxyl group, a sulfonic acid group and an amide group; ; and (11) a production process according to any one of (1) to (10) above, wherein at least several vinyl-based monomers used in suspension polymerization are at least one of the types selected from (meth) acrylic acid and (met) acrylamido-2-methylpropanesulfonic acid.

Moreover, the present invention is (12) a production process according to any one of (1) to (11) above, wherein the polymer microparticles produced by suspension polymerization are polymer microparticles having a water absorption rate of 5 to 50 times, the average particle size from 5 to 50. up to 70 μm in water saturated state for swelling and a ratio of the proportion of particles having a size of 150 μm or greater in the saturated state with water to swell not greater than 0.3% by mass.

According to the present invention, the suspension polymerization using a dispersion stabilizer that is a vinyl-derived monomer derived polymer monomonomer and having an unsaturated radicalizable group as at least one end allows the production of high quality spherical polymer microparticles generally having a suitable particle size from several μm to several tenths of μm with a relatively homogeneous particle size, with good productivity while maintaining high dispersion stability and polymerization stability, without causing aggregation of polymer particles, formation of clusters of these, adhesion of these to the polymerization apparatus, etc. during polymerization and after polymerization.

the adhesion of these to the polymerization apparatus, etc. during polymerization and after the polymerization. In accordance with the present invention, even hydrophilic crosslinked polymer microparticles having a high degree of crosslinking are produced using a large amount of multifunctional vinyl-based monomers, high quality crosslinked hydrophilic polymer microparticles can be produced with homogeneous particle size with high productivity without causing aggregation of polymer particles, formation of clusters of these, adhesion of these to the polymerization apparatus, etc.

In the process presented in the invention, when the macromonomer has an α-substituted vinyl group represented by the formula (I) above as the termination of the vinyl-based monomer derived polymer and / or the macromonomer has a (meth) acryloyl group as the termination of the vinyl-based monomer derived polymer obtained by radical polymerization of a vinyl-based monomer at 150 ° C to 350 ° C, is used as the above-mentioned dispersion-stabilizing macromonomer when a macromonomer having a molecular weight average weight of 1000 to 30,000 is used,and when a macromonomer having hydrophilic vinyl-derived monomer derived constituent units (in particular hydrophilic vinyl-based monomer derived derivatives having carboxylic groups) and hydrophobic vinyl-based monomer derived constituent units [in particular, mono-alkyl derivative-derived components having 8 or more atoms) carbon and (meth) acrylic acid] is used, the above-mentioned excellent effects of the present invention are demonstrated.

With respect to the present invention, polymer microparticles (essentially microparticles), aggregated, spherical polymer microparticles having an average particle size in the range of from 2 to 100 μη, with a homogeneous particle size can be produced smoothly and, in particular, hydrophilic polymer microparticles having a degree of water absorption 5 to 50 times, with an average particle size of 5 to 70 μm in a water saturated state to swell, with a ratio of particles having a particle size of 150 μm or more in a state saturated with water to swell not greater than 0.3% by mass be produced smoothly.

Polymer microparticles obtained by the process presented in the present invention can be used effectively in applications such as cosmetic additives, foundations for various chemical materials, fillers, chromatographic column fillings, light scattering agents, porosity enhancers, weight-reducing agents, anti-blocking agents and modifying agents. surface of recording paper.

Fig. 1 is a diagram showing the instrumentation used to measure the water absorption ratio of polymer particles.

Fig. 2 is a photograph from a digital microscope dispersion of polymer microparticles obtained in Example 1.

Fig. 3 is a digital microscope photograph of polymer microparticles obtained in Example 1 in a water saturated state for swelling.

Fig. 4 is a photograph from a digital microscope dispersion of polymer microparticles obtained in Example 10.

Fig. 5 is a digital microscope photograph of polymer microparticles obtained in Example 10 in a state saturated with water to swell.

Fig. 6 is a digital microscope dispersion of polymer microparticles obtained in Example 11.

Fig. 7 is a digital microscope photograph of polymer microparticles obtained in Example 11 in a water saturated state for swelling.

Burette

Spring clipper

3a Silicone tube

3b Silicone tube

3c Silicone tube

Polytetrafluoroethylene tube

The sealing material

Funnel

Sludge cylinder

Filter paper

9a Filter paper for binding samples (polymer microparticles)

9b Filter paper for binding samples (polymer microparticles)

Cover

Pressure sensitive adhesive tape

Sample (polymer microparticle)

Water after ion exchange

The present invention is described in detail below.

"Polymerization in a vinyl-based monomer slurry" in the present invention contains both: a normal slurry polymerization in which the aqueous phase is a scattering medium, and the oil phase is a dispersoid and a phase inversion slurry in which the oil phase is a scattering medium. and the aqueous phase is a dispersoid.

Generally, when suspension polymerization is performed using a vinyl-based hydrophobic monomer, the polymer microparticles are produced by normal o / w suspension polymerization in which the oil phase (a vinyl-based hydrophobic monomer or an oil phase containing a vinyl-based hydrophobic monomer) is suspended as oil droplets in the aqueous phase, while suspension polymerization is carried out using a vinyl-based hydrophilic monomer, polymer microparticles are produced by w / o suspension suspension suspension in which the aqueous phase (aqueous solution of the hydrophilic monomer based on vinyl) is suspended as water droplets in the oil phase.

In the present invention, in the case of both normal suspension polymerization or suspension polymerization with phase inversion, a "macromonomer having an unsaturated terminal group capable of free radical polymerization derived from a vinyl-based monomer polymer" (hereinafter also referred to as "macromonomer (M)") is used as a dispersion stabilizer.

The macromonomer (M) used as the dispersion stabilizer in the present invention may have a straight chain structure or a structure with 3 or more side chains. When the macromonomer (M) has a straight chain structure, the macromonomer (M) may have unsaturated radicalizable groups only at one end of the chain or may have unsaturated radicalizable groups on both chain ends. When the macromonomer (M) has a structure with 3 or more side chains, it may have unsaturated radicalizable groups on one or more of the 3 or more termini.

Between them, in the present invention, a macromonomer (M) having a straight chain structure and having an unsaturated polymerizable group as only one end is preferably used as a dispersion stabilizer, since it is easy to produce a macromonomer, and its function as a dispersion stabilizer during polymerization in suspension is perfect.

An unsaturated group capable of free radical polymerization of the macromonomer (M) at its terminus can be any as long as it is an unsaturated group that undergoes radical polymerization, and examples of an unsaturated group capable of free radical polymerization of the macromonomer (M) at its termination contain an α-substituted vinyl group having a main chain associated with the α-position of the vinyl group having the polar group X, represented in formula (I) below;

h₂c = c ^<a name="caption1"></a>X (in the formula, X is a monovalent polar group), (meth) acryloyl group, allyl group, isopropenyl group, maleyl group, styryl group and vinylbenzyl group.

Between them, the terminal unsaturated group of the macromonomer (M) capable of radical polymerization preferred as the α-substituted vinyl group represented by formula (I) above [here and everywhere further, also called "α-substituted vinyl group (I)"] or (meth) acryloyl group since the copolymerization with the vinyl-based monomer in the suspension polymerization of the vinyl-based monomer is excellent and good dispersion stability is obtained. The substituted vinyl group (I) is particularly preferred since the copolymerization with the vinyl monomer is excellent and due to the low homopolymerizability there is a low probability that it will be consumed by homopolymerization in the continuous phase.

The "polar group X" in the α-substituted vinyl group (I) represented by formula (I) above means a group having an atom other than carbon and hydrogen or an aryl group, characteristic examples of polar X include -COOR (R is a hydrogen atom or a monovalent group) hydrocarbon), -CONR 2 (R is a hydrogen atom or a monovalent hydrocarbon group), -OR (R is a hydrogen atom or a monovalent hydrocarbon group), -OCOR (R is a hydrogen atom or a monovalent hydrocarbon group), -OCOOR (R is a hydrogen atom or a monovalent hydrocarbon group), -NCOOR (R is a hydrogen atom or a monovalent hydrocarbon group), a halogen atom, -CN, a phenyl group and a phenyl group with a substituent.

Between them, -COOR or are preferred as the polar group X

-CONR2 since the production of the macromonomer (M) can be carried out efficiently and the resulting macromonomer (M) has excellent copolymerizability.

The molecular weight of the macromonomer (M) is preferred from 1000 to 30,000 as the weight average molecular weight, and more preferred from 2000 to 20,000. If the molecular weight of the macromonomer (M) is too low or too high, the dispersion stabilizer function is readily degradable.

The weight average molecular weight of the macromonomer [macromonomer (M)] in the present description is the weight average molecular weight based on polystyrene as determined by gel permeation chromatography (GPC), and a specific measurement method is described in the Examples below.

The main portion of the macromonomer (M) (a portion of the vinyl-derived monomer derived polymer) is formed from one type or two or more types of vinyl-based monomer derived component units, and in particular it is preferred to have both a hydrophobic vinyl-based monomer derived component (here and hereinafter also referred to as the "hydrophobic unit of a vinyl-based monomer") and a hydrophilic vinyl-based monomer derived derivative unit (here and everywhere further referred to as the "hydrophilic unit of a vinyl-based monomer"). When the macromonomer (M) is formed from both a vinyl-based monophobe-based vinyl monomer unit and a hydrophilic vinyl-based monomer unit, it becomes possible that the macromonomer will be present on the surface between the continuous phase (oil phase or water phase) and the dispersed phase (water phase or oil phase) during suspension polymerization, the dispersion stability of the dispersed phase is further increased, and the likelihood that the macromonomer (M) will copolymerize with the vinyl-based monomer present in the expanded phase, it becomes high. The copolymer formed by the copolymerization between the macromonomer (M) and the vinyl-based monomer present in the disperse phase can convey very high dispersion stability to both the disperse phase and the polymer microparticles formed in the process. that the macromonomer (M) will be copolymerized with the vinyl-based monomer present in the dispersed phase becomes high. The copolymer formed by the copolymerization between the macromonomer (M) and the vinyl-based monomer present in the disperse phase can convey very high dispersion stability to both the disperse phase and the polymer microparticles formed in the process. that the macromonomer (M) will be copolymerized with the vinyl-based monomer present in the dispersed phase becomes high. The copolymer formed by the copolymerization between the macromonomer (M) and the vinyl-based monomer present in the disperse phase can convey very high dispersion stability to both the disperse phase and the polymer microparticles formed in the process.

Considering a macromonomer (M) having both a vinyl-based vinyl-based monomer unit and a hydrophilic vinyl-based monomer unit, its hydrophobic moiety of the vinyl-based monomer is preferably formed from a vinyl-based hydrophobic monomer having water solubility at 20 ° C no greater than 2% by mass and particularly not more than 0.5% by mass, which stabilizes the surface between the continuous phase and the disperse phase, thus further improves the dispersion stability during the polymerization in the suspension.

Examples of the monomer having a solubility in water at 20 ° C not greater than 0.5% by mass contain propyl methacrylate, butyl acrylate, butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, stearyl acrylate, stearyl methacrylate, lauryl acrylate, lauryl methacrylate, isobornyl acrylate, isobornyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyl methacrylate, perfluoroalkyl acrylate, perfluoroalkyl methacrylate, benzyl acrylate, benzyl methacrylate, styrene and α-methylstyrene, while examples of a monomer having water solubility at 20 ° C between 0, 5 to 2% by mass contain methyl methacrylate, ethyl methacrylate, propyl acrylate.

The hydrophobic monomer unit based on the vinyl macromonomer (M) can be formed from one type or two types of the above-mentioned vinyl-based hydrophobic monomers.

When a dispersion stabilizer consisting of a macromonomer (M) is used in slurry polymerization with phase reactivity to enhance affinity with the phase of the continuous phase organic solvent (normally the hydrophobic organic solvent phase), the macromonomer (M) preferably has a derivative component from 8 or more alkyl carbon ester and (meth) acrylic acid as a vinyl-based monomer-based monomer unit. The structure of the alkyl group can be a straight chain, branched or cyclic.

Furthermore, the hydrophilic vinyl-based monomer unit (M) having a vinyl-based monomeric vinyl-based monomer unit and a vinyl-based vinylic monomer unit can be formed from a vinyl-based monomer having a hydrophilic group, examples of hydrophilic groups contain a carboxyl group, a sulfonic acid group, sulfinic acid group, phosphoric acid group, phosphonic acid group, salts thereof, hydroxyl group, amino group (including quaternized form thereof and acid neutralized form thereof), amide group, imide group, hydrazide group, urethane group, ureido group, mercapto group.

Exact examples of hydrophilic vinyl-based monomers include vinyl-based vinyl-based monomers and vinyl-based monomers having a group that can be converted to a carboxyl group such as unsaturated monobasic acids such as acrylic acid, methacrylic acid, crotonic acid, vinylacetic acid. and acrylicoxypropionic acid, unsaturated dibasic acids such as maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid and cyclohexene dicarboxylic acid, unsaturated acid anhydrides which form a carboxyl group by hydrolysis such as maleic anhydride and tetrahydrophthalic anhydride; vinyl-based monomers having a hydrophilic group other than a carboxyl group such as acrylonitrile, acrylamide, matacrylamide, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate; vinyl-based monomers having a sulfonic acid group or a phosphonic acid group such as allylsulfonic acid, styrenesulfonic acid, vinylsulfonic acid, acrylamido-2-methylpropanesulfonic acid, methacrylamido-2-methylpropanesulfonic acid, allylphosphonic acid and vinylphosphonic acid; vinyl-based monomers having an amino group such as N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylamide, (partially) acid neutralized forms of these and (partially) quaternized forms of these. vinyl-based monomers having a sulfonic acid group or a phosphonic acid group such as allylsulfonic acid, styrenesulfonic acid, vinylsulfonic acid, acrylamido-2-methylpropanesulfonic acid, methacrylamido-2-methylpropanesulfonic acid, allylphosphonic acid and vinylphosphonic acid; vinyl-based monomers having an amino group such as N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylamide, (partially) acid neutralized forms of these and (partially) quaternized forms of these. vinyl-based monomers having a sulfonic acid group or a phosphonic acid group such as allylsulfonic acid, styrenesulfonic acid, vinylsulfonic acid, acrylamido-2-methylpropanesulfonic acid, methacrylamido-2-methylpropanesulfonic acid, allylphosphonic acid and vinylphosphonic acid; vinyl-based monomers having an amino group such as N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylamide, (partially) acid neutralized forms of these and (partially) quaternized forms of these.

The hydrophilic vinyl-based monomer unit in the macromonomer (M) can be formed from one type or two types of the above-mentioned hydrophilic vinyl-based monomers.

Between them, the macromonomer (M) preferably has a hydrophilic vinyl-based monomer consisting of acrylic acid, methacrylic acid, maleic acid, acrylamide, hydroxyethyl acrylate and hydroxyethyl methacrylate.

When the hydrophilic vinyl-based monomer forms a hydrophilic vinyl-based monomer unit in the macromonomer (M) has an acidic group such as a carboxyl group as a hydrophilic group, at least some acidic groups can be neutralized by bases (sodium hydroxide, potassium hydroxide, ammonia, amine compounds) , etc.) depending on the situation.

When a dispersion stabilizer consisting of a macromonomer (M) is used in a phase inversion suspension polymerization, the macromonomer (M) preferably has a vinyl-based monomer unit having a carboxyl group as a hydrophilic vinyl-based monomer unit. In this process, a vinyl-based vinyl monomer unit having a carboxyl group can be introduced directly into the macromonomer (M) by producing a macromonomer (M) using a vinyl-based monomer having a carboxyl group, or the carboxyl group can be introduced into the macromonomer by producing a macromonomer using a monomer-based monomer. on vinyl having a group that can react with a carboxyl group, a carboxylic acid anhydride group, etc. (e.g., a hydroxyl group, an epoxy group, an amino group, an oxazoline group, etc.), and then the reacting macromonomer with a carboxyl-forming compound (dicarboxylic acid, dicarboxylic acid anhydride, etc.). Alternatively, the carboxyl group may be introduced into the macromonomer by synthesizing a macromonomer having a decomposable ester linkage containing the (meth) acrylic acid ester as a vinyl-based monomer unit, and by decomposing the ester bond.

The content of the hydrophobic monom unitbased on vinyl and the hydrophilic vinyl-based monomer unit in the macromonomer (M) may vary depending on the type of suspension polymerization (polymerization in normal suspension or suspension polymerization with phase inversion), type and composition of the vinyl-based monomer polymerizable in a suspension, a type of polymer microparticles produced by suspension polymerization, intended use, etc., but in order to obtain a macromonomer (M) exhibiting good functions as a dispersion stabilizer, the ratio of the hydrophobic vinyl-based monomer unit is generally from 1 to 99% by mass with respect to the macromonomer mass (M), and particularly preferably between 5 and 95% by mass, and the ratio of the content of the hydrophilic vinyl-based monomer unit is from 1 to 99% by mass,and particularly preferred from 5 to 95% by mass.

When the macromonomer (M) is produced using a vinyl-based monomer, a small amount of polymer lacking unsaturated polymerizable radical groups at the ends (non-macromonomer polymer) can be produced as a by-product together with a macromonomer having an unsaturated polymerizable radical group at the termination and the difficulty of separating the macromonomer from the non-macromonomer polymer, the macromonomer is used in a state containing a non-macromonomer polymer; when the used macromonomer (M) contains small amounts of non-chromomeric polymer, the ratio of the hydrophobic vinyl-based monomer unit and the ratio of the hydrophilic vinyl-based monomer unit based on the macromonomer (M) is the ratio of the total macromonomer (M),

In particular, when the phase inversion slurry polymerization is carried out using a macromonomer (M) as a dispersion stabilizer, using a macromonomer (M) containing a component derived from 8 or more carbon alkyl ester and (meth) acrylic acid (hydrophobic) as a dispersant stabilizer. a vinyl-based monomer unit) in a proportion of 30 to 99% by mass, in particular 60 to 90% by mass based on the total weight of the macromonomer (M) and a derived component of a vinyl-based monomer having a carboxylic group (a vinyl-based vinyl-based monomer) in a ratio of 1 to 70% by mass, in particular 10 to 40% by mass, allows the achievement of extremely high stability for the continuous phase and the disperse phase, and excellent polymerization stability has been obtained.

The method for preparing the macromonomer (M) is not particularly limited, it can be produced using traditionally known methods (e.g., Patent Publication 5, 6 and 7).

Although not limited, examples of a macromonomer production process having an α-substituted vinyl group (I) at the end and a macromonomer having a (meth) acryloyl group at the term preferably used in the present invention are described below.

[Example of a macromonomer production process having an α-substituted vinyl group (I) on the end] (a) A macromonomer having an α-substituted vinyl group (I) on a polymer end containing vinyl derived monomer derived monomer units may be produced by radical polymerization from a monomer-based monomer. on vinyl (preferably, the vinyl-based hydrophobic monomer mentioned above and a vinyl-based hydrophilic monomer), which is a substrate for the macromonomer (M) at 150 ° C to 350 ° C, preferably 180 ° C to 320 ° C and more preferably 190 ° C to 270 ° C.

As a source of radicals in a radical polymerization reaction, a thermally associated vinyl-based monomer reaction such as styrene or a radical polymerization catalyst can be used. When the radical polymerisation catalyst is used, a traditionally known catalyst may be used, with specific examples containing organic peroxides such as benzoyl peroxide, lauroyl peroxide, orthochlorobenzoyl peroxide, orthomethylbenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxide-2-ethylhexanoate, di-t-butyl peroxide, di-t-hexyl peroxide, dith-amyl peroxide and t-butyl pivalic peroxide; azo compounds such as azobis (2-methylpropanoic dinitril), azobiscyclohexa carbonitrile and azobis (2,4-dimethylceric) nitril; and persulfide compounds such as potassium persulfide.

Any known radical polymerization method can be used to carry out radical polymerization of a vinyl-based monomer, and between them radical polymerization by mass polymerization or solution polymerization are preferred from the viewpoint of macromonomer production efficiency.

Polymerization can be carried out as batch polymerization, continuous polymerization, but semi-batch polymerization (the substrate is dosed continuously, the reaction mixture is not continuously extracted), etc., and continuous poly merization is preferred from the point of view of obtaining a narrow composition distribution and molecular weight and high homogeneity of the macromonomer. In particular, continuous polymerization using a stirred tank reactor is preferred.

(b) When the method (a) described above is used a small amount of polymer lacking unsaturated groups, end-curable radical polymerization (non-metromonomer polymer) is often produced as a by-product together with a macromonomer having an α-substituted vinyl group (I) at the end, but as described above, since the separation of a non-macromonomer polymer from a macromonomer having unsaturated radicalizable radical groups at the terminus is difficult, in the present invention as a macromonomer (M) containing a small amount of non-bromomonomer polymer is used as a dispersion stabilizer. In order to disclose the full function of the macromonomer (M) as a dispersion stabilizer, including the macromonomer (M) used in the present invention,

In order to obtain a macromonomer (M) having a high ratio of macromonomer content having unsaturated radical polymerizable groups at the ends of the macromonomer polymerization plant, the polymerization is carried out so that the total vinyl-based monomer content and the resulting polymer (macromonomer, etc.) are 50 to 100% by mass relative to the total weight of the polymerization plant, more preferably 60 to 100% by mass and particularly preferably 70 to 100% by mass, hence the polymerisation for the production of the macromonomer is carried out so that the total solvent content is preferably not more than 50% by mass more preferably no more than 40% by mass, particularly preferably no more than 30% by mass.

When the macromonomer is produced using a solvent, it is preferable to use a solvent that dissolves the vinyl-based monomer to produce a macromonomer and does not precipitate the produced macromonomer or other polymers. Particular examples of the solvent that can be used include aromatic alcohols such as benzyl alcohol, aliphatic alcohols such as isopropanol and butanol, ketones such as methyl ethyl ketone and isobutyl methyl ketone, esters such as butyl acetate, ethylene glycol monoalkyl esters such as methyl CELLOSOLVE and butyl CELLOSOLVE monoalkyl esters of diethylene glycol such as carbitol, ethylene glycol dialkyl ethers such as ethylene glycol dimethyl ether and diglycol ethers such as diglycol methyl ether.

Further, when the macromonomer (M) is produced by the method (a) described above, if it is preferred that the copolymer formed by the copolymerization of the macromonomer (M) and the vinyl-based monomer present in the dispersed phase during suspension polymerization has a high copolymer ratio having a broad molecular weight distribution and graft polymer structure with vinyl monomer, a vinyl-based monomer ratio having no hydrogen atom in the α-position of the vinyl group not higher than 50 mole% as the macromonomer-building monomer is preferred, and more preferably no greater than 30 mole%.

In contrast, if it is preferred that the copolymer formed by copolymerization with the vinyl-based monomer present in the dispersed phase has a high ratio of a copolymer having a narrow molecular weight distribution and the block polymer structure with the vinyl monomer, a vinyl-based monomer ratio not preferable is preferred. a hydrogen atom in the α-position of the vinyl group (e.g., having a methyl group in the α-position) of 30 mole% or more as a macromonomer building monomer, and more preferably 50 mole percent or more.

After suspension polymerization, if it is desired that the copolymer formed by the copolymerization of the macromonomer (M) and the vinyl-based monomer present in the expanded phase is removed by washing, etc., it is preferred to select a second method from the above.

Furthermore, when the macromonomer (M) is produced by the method (a) described above, it is preferred to use a vinyl-based monomer having no hydrogen atom in the α-position of the vinyl group (e.g. having a methyl group in the α-position) as a hydrophobic monomer constructing a macromonomer , while the vinyl-based monomer having a hydrogen atom in the α-position of the vinyl group, as a hydrophilic monomer, if a dispersion stabilizer for suspension suspension polymerization is obtained. This is due to the fact that the polar group X bound to the terminal unsaturated bond is derived from the hydrophilic monomer unit, and the terminal unsaturated bond can more easily approach the dispersed (hydrophilic) phase in suspension suspension polymerization and is easily copolymerized.

[Examples of the production of a macromonomer having a (meth) acryloyl group at the end] (a) A macromonomer having an (meth) acryloyl group on the end is produced by producing a polymer having a reactive group (e.g., a carboxyl group, etc.) at the completion by radical polymerization of a monomer-based monomer. vinyl (preferably a vinyl-based vinyl-based monomers and a vinyl-based hydrophilic monomer) using a standard method using a radical polymerization catalyst followed by reaction of glycidyl (meth) acrylate, (meth) acryloyl chloride and the like with a terminal reactive group to join the group (acrylic) acrylic to complete.

which may form a carboxyl group such as a dicarboxylic acid-deficient reactor with a side-chain hydroxyl group, resulting in a macromonomer having a (meth) acryloyl group on the end and having a side carboxyl group in the molecular chain. In this process, the examples of macromonomer-utilized vinyl-based monomers having a hydroxyl group include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol mono (meth) acrylate and compounds in which ε - caprolactone is added to hydroxyethyl (meth) acrylate (n. Placcel, manufactured by Daicel Chemical Industries, Ltd.).

(c) In a reaction producing a macromonomer in (a) and (b) above, a polymer having a reactive group (e.g., a carboxylic group) at the end of the polymer was used as a method of producing the polymer used to make the macromonomer by incorporating the (meth) acryloyl group into the ends as a polymer , a process for the preparation of a carboxyl-containing polymer at the end can be cited by subjecting the vinyl-based monomer to radical polymerization in an organic solvent in the presence of a mercaptan having a carboxyl group such as mercaptoacetic acid, mercaptopropionic acid, mercaptobutyric acid or thiosalicylic acid.

In the radical polymerization of a vinyl-based monomer in the presence of a mercaptan having a carboxyl group, the mercaptan has the function of a chain transfer agent to introduce the carboxyl group to the ends of the polymer. The preferred amount of mercaptan used is equimolar to the polymer obtained by radical polymerisation and can be readily calculated from the amount of monomer used and the desired average molecular weight molecule, etc. When a polymer having a weight molecular weight of 1000 to 30,000 is obtained, the amount of mercaptan used is preferably between 0.1 to 5g per 100g of vinyl-based monomer. Furthermore, the polymerization temperature during radical polymerization is preferably between 50 ° C and 140 ° C, and ethyl acetate, butyl acetate is preferably used as the solvent in the polymerization,

In the present invention, polymer microparticles are produced by suspension polymerization of a vinyl-based monomer using the above-mentioned macromonomer (M) as a dispersion stabilizer.

The vinyl-based monomer for the polymerization in suspension may be any free-radical-polymerizable vinyl-based monomer.

As described above, when the vinyl-based monomer selected for suspension polymerization is a hydrophobic vinyl-based monomer, the macromonomer (M) is used as a dispersion stabilizer, the polymer microparticles are produced by o / w-suspension in which the oil phase (hydrophobic) a vinyl-based monomer or an oil phase containing a vinyl-based hydrophobic monomer) is suspended as oil droplets in the aqueous phase.

butylstyrene, nonylstyrene, methoxystyrene,

Moreover, when the vinyl-based monomer selected for suspension polymerization is a hydrophilic vinyl-based monomer, the macromonomer (M) is used as a dispersion stabilizer, the polymer microparticles are produced by slurry suspension with a w / o-phase inversion in which the aqueous phase (the aqueous solution in which the vinyl-based hydrophilic monomer is dissolved) is suspended as water droplets in the oil phase.

As a vinyl-based hydrophobic monomer used in o / w normal phase polymerization, any free-radically polymerizable vinyl-based hydrophilic monomer can be used, and this is not particularly limited. Particular examples of vinyl-based hydrophobic monomer that can be used in normal phase polymerization in the suspension include styrenes such as styrene, omethylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn -butylstyrene, p-tertp-n-hexylstyrene, p-decylstyrene, p-phenylstyrene, dichlorostyrene, acrylic and methacrylic acid derivatives such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) acrylate n-butyl, isobutyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate,

Furthermore, any hydrophilic vinyl-based polymerizable monomer can be used as a vinyl-based hydrophilic vinyl-monomer used in w / o phase inversion polymerization, and this is not particularly limited. For example, as a vinyl-based hydrophilic monomer that can be used in suspension phase polymerization, a vinyl-based hydrophilic monomer having a hydrophilic group such as a carboxyl group, a sulfone group, a phosphono group, an amido group, an amino group, a group can be used. hydroxyl. Particular examples of vinyl-based hydrophilic monomers that may be used include vinyl-based monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monobutyl itaconate, monobutyl maleate and cyclohexene dioic acid and (partially) neutralized with base forms; vinyl-based monomers having an amino group such as N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylamide ( partially) acid-neutralized forms of these, and (partially) quaternized forms of these; N-vinylpyrrolidone and acryloylmorpholine; vinyl-based monomers having a phosphoric acid group such as phosphloxethyl acid methacrylate, phosphoxypropyl acid methacrylate and 3-chloro-2-phosphoxypropyl acid methacrylate and (partially) alkaline neutralized forms thereof; vinyl-based monomers having a sulfonic acid or phosphonic acid group such as 232 (meth) acrylamido-2-methylpropanesulfonic acid, (2-sulfoethyl) (meth) acrylate, 2- (meth) acryloyl-ethanesulfonic acid, allylsulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allyl phosphonic acid and vinylphosphonic acid and (partially) basically neutralized forms thereof; nonionic hydrophilic monomers such as (meth) acrylamide, N, N-dimethylacrylamide, Nizopropylacrylamide, N-methyl (meth) acrylamide, Nalkoxymethyl (meth) acrylamide, (meth) acrylonitrile, hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate, one type or two or more types of these can be used.

Between them, it is preferable to perform suspension phase inversion polymerization using one type or two or more types of (meth) acrylic acid, (meth) acrylamide and 2-acrylamido-2-methylpropanesulfonic acid in view of excellent polymerizability and excellent water absorption characteristics of the resulting microparticles. polymer.

Moreover, in the present invention, during the suspension polymerization, a vinyl-based monomer, a polyfunctional vinyl-based monomer having two or more unsaturated radical polymerizable groups together with one type or two or more types of the monofunctional hydrophobic based monomers mentioned above can be used. on vinyl and hydrophilic vinyl-based monomers. In particular, when hydrophilic polymer microparticles are produced by suspension-suspended polymerization with a phase inversion of a hydrophilic vinyl-based monomer using a macromonomer (M) as a dispersion stabilizer, it is preferred to use a multifunctional vinyl-based monomer together with a monofunctional compound,

Thus, the "vinyl-based monomer" referred to in the present invention is the general statement for a monofunctional vinyl-based monomer and a multi-functional vinyl-based monomer.

Any vinyl-based monomer can be used as a multifunctional vinyl-based monomer if only the vinyl-based monomer will have two or more groups that can undergo radical polymerization with a hydrophilic vinyl-based monomer or with a vinyl-based hydrophobic monomer as a base; particular examples thereof include di- or tri (meth) acrylates of polyols such as polyethylene glycol di (meth) acrylate, polypropylene di (meth) acrylate, glycerol tri (meth) acrylate, trimethylpropane tri (meth) acrylate and tri (met) oxide-modified ethylene trimethylopropane acrylate, bisamides such as methylene bis (meth) acrylamide, divinyl benzene and allyl (meth) acrylate, one type or two or more types thereof can be used.

Between them, as a multifunctional vinyl-based monomer used in suspension polymerization with phase inversion, the use of polyethylene glycol diacrylate or methylenebisacrylamide is preferred, if their solubility in a water-based mixture and a vinyl-based hydrophilic monomer is excellent, also an advantage if increasing the amounts used allows you to achieve a higher degree of crosslinking.

When the vinyl-based multifunctional monomer is used during suspension polymerization, the ratio of the vinyl multifunctional monomer used may depend on the type of vinyl-based multifunctional monomer used, the intended use of polymer microparticles obtained in suspension polymerization, etc., and when polymer microparticles require the crosslinking characteristics are preferred 0.1 to 100 moles with respect to 100 moles of the total monofunctional vinyl-based monomer (no macromonomer) used in the slurry polymerization, more preferably 0.2 to 50 moles, and particularly preferably 0.5 to 10 moles .

hydrophilic crosslinked polymer microparticles having a water absorption rate of 5 to 50 times, having an average particle size in water saturated state to swell of 5 to 70 pm, and for which the ratio of particles in the water-swollen size to swell ratio 150 can be produced freely μm or more is not greater than 0.3% by mass. However, it is possible to use a monofunctional vinyl-based monofilament-based monomer based on vinyl other than the above-mentioned (meth) acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid depending on the desired characteristics of the polymer microparticles, the amount used is preferably no greater. than 80% by mass with respect to the total amount of monofunctional vinyl monomer, more preferably not more than 50% by mass. As another hydrophilic vinyl-based monomer used in combination, from the viewpoint of good polymerization stability and the ease of obtaining polymer microparticles having the above-mentioned characteristics, (meth) acrylamide and hydroxyethyl (meth) acrylate are preferred, and (meth) acrylamide is particularly preferred. Moreover, when a polyethylene glycol diacrylate is used as a multifunctional vinyl-based monomer, the average amount of ethylene oxide repeats in the polyethylene glycol unit is preferably from 2 to 20, more preferably from 3 to 10. As a basic compound to obtain (partly) base-neutralized, the base may basic metal hydroxides (sodium hydroxide, potassium hydroxide, etc.), ammonia or amine compounds may be used. If it is desirable, to hide basic compounds from polymer microparticles by evaporation, it is preferable to use basic metal hydroxides, but if it is desired to remove by evaporation, etc. basic compounds it is preferable to use ammonia or a low boiling amine compound. The degree of neutralization of the vinyl-based monomer is preferred from 1% to 100%, more pref- erably from 10% to 95% and particularly preferred from 40% to 90%. When a monomer having a carboxylic acid group or a carboxylic acid salt such as a (partially) neutralized (meth) acrylic acid salt as a vinyl-based monomer is used, the degree of crosslinking can be increased by using a compound having two or more functional groups that react with the carboxyl group. As such a compound, a multifunctional epoxy compound is preferred, and particularly preferred are diglycidyl ether and ethylene glycol and a glycidyl ether and polyethylene glycol. As a method for adding these compounds, there is a method in which these compounds are added to the vinyl-based monomer before the monomer polymerization and the method in which they are added to the polymer microparticle suspension after polymerization, any method can be selected.

The polymerization in the suspension of the vinyl-based monomer to produce polymer microparticles can be carried out in the same manner as the traditional suspension polymerization, except that the macromonomer (M) is used as the dispersion stabilizer. Polymerization in suspension can be carried out by continuous, batch and semi-batch methods. In the case of the batch method, the vinyl monomer can polymerize all at once or in portions.

When o / w-suspension polymerization is carried out using a vinyl-based hydrophilic monomer, polymer microparticles are produced by carrying out the polymerization normally at 10 ° C to 100 ° C using the free radical polymerization catalyst in the presence of a macromonomer dispersion stabilizer (M) by dispersing aqueous phase oil droplets (aqueous dispersing medium), the oil phase comprising a hydrophobic monofunctional vinyl-based monomer and a water-based monophobic monofunctional monomer dissolved in a suitable water-insoluble organic solvent, with a multifunctional vinyl-based monomer added as needed.

In the normal suspension polymerization phases, examples of water-insoluble organic solvents that could be used to dissolve the vinyl-based hydrophobic monofunctional monomer include aliphatic hydrocarbons having 6 or more carbon atoms, aromatic hydrocarbons such as benzene, toluene and xylene, solvent-based solvents. on ketones such as methyl isobutyl ketone and esters such as isoamyl acetate.

Further, the macromonomer (M) is preferred if it has high hydrophilicity (the proportion of the hydrophilic monomer unit is high) and it is preferably added to the polymerization system by dissolution or homogeneous dispersion in a polar solvent such as an alcohol. Furthermore, when it is dissolved in water, the macromonomer (M) is preferred if it does not form micelles in water. The forming micelle undergoes an emulsion polymerization reaction at the same time as the suspension polymerization, which leads to the undesirable formation of a large number of microparticles of 1 μm or less.

The amount of macromonomer (M) used [the amount used also contains a small amount of non-macromonomer polymer, if it is contained in the macromonomer (M)] 0.1 to 50 parts by mass is preferred with respect to 100 parts by mass of vinyl-based monomer (no containing a macromonomer) to obtain polymer microparticles with a homogeneous particle size while maintaining good dispersion stability, more preferably 0.2 to 20 parts by mass, even more preferred 0.5 to 10 parts by mass. When the amount of macromonomer (M) used is too low, the dispersion stability of the vinyl-based monomer and the resulting polymer microparticles in the polymerization system become weak, polymer microparticles readily form aggregates, precipitate and have a large particle size divergence. On the other hand,

Furthermore, in a normal phase suspension polymerization, it is preferred to polymerize such that the mass ratio of the aqueous phase (scattering medium) to the oil phase (Dispersoid) in the polymerization system is 99: 1 to 40:60 and especially 95: 5 to 60:40. so that it is possible to achieve a balance between productivity, dispersion stability during polymerization and particle size control of polymer microparticles.

Furthermore, it is preferred to carry out a normal phase polymerization with mixing and in a state in which oil droplets comprising a vinyl-based hydrophobic monomer (oil phase) are dispersed in the aqueous phase (scattering medium) in a particle size of 1 to 500 μη, and particularly 2 to 100 pm to make it possible to obtain polymer microparticles with a suitable and homogeneous particle size.

On the other hand, when w / v phase inversion polymerization is carried out using a vinyl-based hydrophilic monomer, hydrophilic polymer microparticles are produced while generally polymerizing at 10 ° C to 100 ° C using a free radical polymerization catalyst in the presence of a dispersion stabilizer. containing a macromonomer (M), disperse the aqueous phase, which is an aqueous solution containing a vinyl-based hydrophilic monomer (or neutralized form thereof) dissolved in water, in an oil phase (a scattering medium containing a hydrophobic organic solvent) in the form of fine aqueous drops.

In reverse phase polymerization as a hydrophobic oil forming organic phase (scattering medium), for example, aliphatic hydrocarbon solvents with 6 or more carbon atoms may be used, aromatic hydrocarbon solvents such as benzene, toluene, xylene and ethylbenzene, solvents based on silicones such as octamethylcyclotetrasiloxane, etc., are particularly preferred for use with hexane, cyclohexane, nheptane because the solubility of the vinyl-based monomer and the water content in it is small, they are easy to remove after polymerization.

In this phase inversion suspension polymerization, the hydrophilic vinyl-based monomer (or its neutralized salt) can be dissolved in water and added to the polymerization system as an aqueous solution. The concentration of the vinyl-based hydrophilic monomer added to the polymerization system in the aqueous solution in which the vinyl-based hydrophilic monomer is dissolved is preferred 5 to 80% by mass, and particularly preferably 20 to 60% by mass, so that the suspension polymerization with phase inversion can be be carried out smoothly with good productivity.

When the hydrophilic vinyl-based monomer used in the phase inversion suspension polymerization is a vinyl-based monomer having an acidic group such as a carboxyl group or a sulfonic acid group, the aqueous solution in which the vinyl-based hydrophilic vinyl-based monomer is well-dissolved can be prepared by adding a vinyl-based hydrophilic monomer to water, followed by neutralization of the acid group of a vinyl-based monomer with an aqueous alkaline solution such as aqueous ammonia, aqueous sodium hydroxide or aqueous potassium hydroxide.

In this process, it is highly preferred to use a vinyl-based multifunctional monomer [in particular, the above-mentioned special multifunctional vinyl-based monomers] together with a monofunctional vinyl-based hydrophilic monomer as a vinyl-based hydrophilic monomer that is dissolved in water and added to the polymerization system .

Moreover, in suspension suspension polymerization, the macromonomer (M) is preferably dissolved or homogeneously dispersed in the hydrophobic organic solvent to form a dispersing medium (oil phase) and added to the polymerization system.

The amount of macromonomer (M) used [the amount used also contains a small amount of non-macromonomer polymer if the macromonomer (M) contains] 0.1 to 50 parts by mass is preferred with respect to a total of 100 parts by mass of a vinyl-based monomer (no macromonomer) ) to obtain hydrophilic polymer microparticles with a homogeneous particle size while maintaining good dispersion stability, more preferred 0.2 to 20 parts by mass, and especially preferably 0.5 to 10 parts by mass. When the amount of macromonomer (M) used is too low, the dispersion stability of the vinyl-based monomer and the resulting polymer microparticles in the polymerization system become weak, and the resulting polymer microparticles are easily aggregated, precipitated and have a large particle size divergence. On the other hand,

Moreover, in suspension polymerization with phase inversion it is preferred to polymerize such that the mass ratio of the oil phase (scattering medium) to the aqueous phase (dispersed) in the polymerization system is 99: 1 to 20:80, especially 95: 5 to 30 : 70 so that a balance can be achieved between productivity, dispersion stability during polymerization and particle size control of polymer microparticles.

Furthermore, it is preferred to polymerize the suspension with stirring and to conduct the polymerization in a state in which water droplets comprising a vinyl-based hydrophilic monomer (aqueous phase) are dispersed in the oil phase (scattering medium) in particles of size 1 to 1000 μm, and especially 2 to 500 [mu] m, so that hydrophilic polymer microparticles having appropriate and uniform sizes can be obtained.

In the above-mentioned suspension polymerization (phase-in-suspension polymerization and phase inversion polymerization), any known radical polymerisation catalyst that is conventionally used in the polymerization of a vinyl-based radical monomer can be used as a radical polymerization catalyst. Examples of the free radical polymerization catalyst that may be used include organic peroxides such as cumene hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, lauryl yl peroxide, ortho-chlorobenzoyl peroxide, orthometloxybenzoyl peroxide, 3,5,5-trimethylhaxanoyl peroxide, t-butylperoxide-2-ethylhexanoate, peroxide. di-t-butyl, t-butyl pivalic peroxide, azo compounds such as azobisisobutyronitrile, azobiscyclohexacarbonitrile and azobis (2,4-dimethylvaleronitrile),

If the suspension polymerization is of normal phase suspension polymerization, the preferred free radical polymerization catalyst is the one with high solubility in the disperse phase (oil phase) whose radical formed by the disintegration thereof has low solubility in water, especially benzoyl peroxide or lauroyl peroxide.

Furthermore, when suspension polymerization is a suspension polymerization with phase inversion, the one with high solubility in the disperse phase (aqueous phase) is preferred, whose radical formed by the disintegration thereof has low solubility in the continuous phase (oil phase), and salts are particularly preferred peroxodisulfuric acid such as potassium peroxodisulfate and ammonium peroxodisulfate or hydroperoxide compounds such as t-butyl hydroperoxide and cumene hydroperoxide. Decomposition of the initiator (radical formation) may use heat or a redox reaction to reduce the compound. It is preferable to use a redox reaction to initiate low temperature polymerization, and to increase the concentration of vinyl-based monomer in the liquid of the polymerization reaction and increase the degree of polymerization, thus allowing the increase in the productivity and molecular weight of the molded polymer. As the reducing compound used to initiate the redox, any conventionally known reducing compound can be used, and sodium sulfate, sodium bisulfate, sodium bisulfate are preferred. These reducing compounds are preferably added as aqueous solutions after addition of the disperse phase (aqueous phase) to the continuous phase (oil phase) and disperse the dispersed phase to the desired particle size. As the oxidizing agent for the redox reaction, any of the above peroxides and salts of peroxosulphuric acids can be used; the preferred one is that it will be soluble in both phases, the oil phase and the water phase to obtain a good degree of polymerization,

The amount of radical polymerization initiator used may be adapted to the type of vinyl-based monomer used, the particle size or molecular weight of the polymeric microparticle, etc., and is generally preferred, based on the total weight of the vinyl-based monomer, 0.001 to 5% by mass and particularly preferably 0.01 to 1% by mass. When the amount of free radical polymerization catalyst used is too small, the yield of polymer microparticles can decrease, however, if it is too large, the molecular weight of the polymer may drop, the strength or water absorption capacity of the polymer microparticles may be insufficient, the degree of polymerization becomes too high, and in some cases, suspension polymerization can not be carried out in a stable manner.

In a suspension suspension polymerization in the present invention, together with a dispersion stabilizer comprising a macromonomer (M), another dispersion stabilizer may be used in combination, if necessary. In particular, when adjusting the particle size of the polymer microparticle to the desired one, it may be effective to use a different dispersion stabilizer in combination.

Particular examples of other dispersion stabilizers that can be used in the phase inversion suspension polymerisation include non-ionic surfactants such as fatty acid ester and sorbitan, fatty acid esters and polyglycerol, fatty acid esters and sucrose, fatty acid esters and sorbitol and polyoxyethylene and alkyl ethers. . In particular, it is preferred to use a relatively highly hydrophobic nonionic surfactant having HLB from 2 to 10 such as sorbitan monooleate or sorbitan monopalmitate, and one type or two or more types of these can be used.

When other dispersion stabilizers are used including a dispersion stabilizer containing a macromonomer (M), the amount of the other dispersion stabilizer used is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the vinyl-based monomer, and particularly preferably 0.1 to 10 parts mass. When the amount of the other dispersion stabilizer used is too high, the dispersion stability during polymerization may decrease or the amount of fine particles 1pm or smaller produced as a by-product may increase.

The dispersion in which the polymer microparticles are dispersed in the liquid is obtained by performing the polymerization in a suspension of the vinyl-based monomer as above. The method of collecting polymer microparticles from a suspension is not particularly limited and can be carried out by conventionally known methods. As a method for collecting polymer microparticles, example (1) may be cited, in which a suspension containing polymer microparticles is introduced for heating and / or vacuum treatment to remove volatile liquid solvent portions, thus producing dry polymer microparticles, (2) a method, in which the suspension of polymer microparticles is subjected to sedimentation, centrifugation, decanting, filtration, etc., to collect polymeric microparticles which are then subjected to washing, if necessary,

In the case of suspension polymerization with phase inversion, if water is present in the polymeric microparticles forming the dispersed phase, it is preferable to initially remove the water from the polymer microparticles by azeotropic dehydration, etc. before drying the polymer microparticles and then carry out the drying. Drying after the initial removal of water prevents the polymer microparticles from sticking together during drying, thus producing polymer microparticles having excellent dispersion.

The drying of polymer microparticles is generally carried out at a temperature of the solution or dry dust in powder form from 40 ° C to 100 ° C, and particularly preferably from

50 ° C to 90 ° C.

According to the suspension polymerization process in the present invention described above, spherical polymer microparticles having a suitable particle size within a certain range can be produced with high productivity, a homogeneous particle size without causing aggregation of polymer particles, formation of clusters of these, adhesion to polymerization equipment, e.t.c.

The polymer microparticles obtained in the process of the present invention in which the suspension polymerization of a vinyl-based monomer is carried out using a macromonomer (M) as a dispersion stabilizer have an average particle size of from 2 to 100pm.

In the present invention, when the suspension polymerization with phase inversion is carried out under conditions in which the used macromonomer has in particular an α-substituted vinyl group or an acryloyl group, the weight molecular weight of the macromonomer is equal to 1000 to 30,000 and the macromonomer has a derivative derived from an alkyl ester having 8 or more carbon atoms and (meth) acrylic acid and a monomer unit having a carboxyl group, it is possible to obtain spherical polymer microparticles having an average particle size in the range of from 2 to 100pm and having a uniform particle size (having several coarse particles).

According to the process of the present invention, polymer microparticles (hydrophilic polymer microparticles) having a water absorption rate of 5 to 50 times, an average particle size in water saturated state to swell from 5 to 70 μm, and a ratio of particles having a particle size of 150 μm or more in the state of saturation with water to swell not greater than 0.3% by mass.

In particular, conducting suspension polymerization using a vinyl-based monomer (monofunctional vinyl-based monomer) in a (partly) neutralized form with (meth) acrylic acid base or in a (partially) neutralized form with 2-acrylamido-2-methylpropanesulfonic acid base, which is a hydrophilic base a vinyl-based monomer in an amount of 50% by mass or more of the total amount of monofunctional vinyl-based monomer followed by at least one type of vinyl-based multifunctional monomers mentioned above (in particular, at least one type of polyethylene glycol diacrylate or methylenebisacrylamide) based on total 100 moles of monofunctional vinyl-based monomer from 0.1 to 100 moles, more from 0.2 to 50 moles, especially from 0.5 to 10 moles,and the macromonomer (M) relative to the total weight of the vinyl-based monomer from 0.1 to 50% by mass, and especially from 0.5 to 10% by mass, can be produced hydrophilic polymer microparticles having a water absorption rate of 5 to 50 times, average particle size from 5 to 70pm in a water-saturated state to swell, and a ratio of particles having a particle size of 150pm or greater in a saturated water-swollen state of not greater than 0.3 mass%.and a ratio of particles having a particle size of 150 μm or more in a state of saturation with water to swell not greater than 0.3% by mass.and a ratio of particles having a particle size of 150 μm or more in a state of saturation with water to swell not greater than 0.3% by mass.

Furthermore, the particle size of the polymer microparticle formed by suspension polymerization can be adjusted by adjusting the mixing conditions in the polymerization system during the suspension polymerization.

Here, the average particle size of polymer microparticles (dried polymer microparticles), the degree of water absorption of polymer microparticles, the average particle size in water saturated state for swelling, the ratio of particles having a particle size of 150pm or more in water saturated state to swell with respect to the present invention are measured or obtained using the methods described below in the Examples section.

The present invention is explained in detail below by reference to Examples, etc., but the present invention is not limited to the following Examples.

In the Examples below, the solid concentration in a liquid, the weight average molecular weight and the number average molecular weight of the macromonomer, the percentages of introduction of terminal ethylenically unsaturated (terminal percentages of introduction of unsaturated ethylenically) in the macromonomer, which has an α-substituted vinyl group, the adhesion limit of polymer microparticles for polymerization reactor, amount of residue on a polyethylene filter (200 mesh, mesh 114pm) from a polymer microparticle suspension obtained by suspension polymerization, average particle size of polymer microparticles, water absorption rate of polymer microparticles, average particle size of polymer microparticles in water saturated state to swell .the ratio of particles having a particle size of 150 μm or more of polymer microparticles in a water saturated state to swell has been measured and calculated as follows.

(1) Concentration of a solid in a liquid:

About 1 g of a sample of liquid containing the solid was collected in a bottle whose weight was measured [weight of bottle = B (g)] and the whole bottle was thoroughly infested [W0 (g)], a bottle of liquid with liquid sample was put into the windless drier and dried at 150 ° C for 1 hour, then the weight of the entire weighing bottle was measured [W1 (g)] and the solid-state concentration (NV) (mass%) was calculated from Equation (I) below:

Solid state concentration (NV) (mass%) = {(W1-B) / (W0B)} χ100 (I) (2) Molecular weight weight average (Mw) and molecular weight average number (Mn) of the macromonomer:

The molecular weight of the macromonomer (if a small amount of non-macromonomer polymer is contained: a macromonomer containing a non-macromonomer polymer) was measured by gel permeation chromatography (GPC) and the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the macromonomer were determined on the basis of polystyrene.

Specifically, HLC-8120 GPC manufactured by Tosoh Corporation was used as GPC equipment, TSKgel super MP-M (4 columns) were used as columns, a solution in which the macromonomer was dissolved in tetrahydrofuran (concentration 5 mg / ml) was used as a sample , tetrahydrofuran was used as a scrubbing solvent, measurements were made at flow conditions of 0.6ml / min and column temperature of 40 ° C. The results of the measurements were analyzed using a calibration curve based on a polystyrene standard, and then the mass average molecular weight (Mw) and the number average molecular weight (Mn) of the macromonomer (macromonomer composition) based on polystyrene were determined.

(3) Percent introduction of (F) a terminal unsaturated ethylene group into a macromonomer having an α-substituted vinyl group:

With respect to a macromonomer having an α-substituted vinyl group (if a small amount of a non-macromonomer polymer is included: a macromonomer containing a non-macromonomer polymer) produced in the process described in Production Example 1, from the macromonomer monomer component of the macromonomer monomer composition determined by the method described in Example 1, o Mn determined from (2) above, the amount of protons of methylene groups bound to the ester bonds of the (meth) acrylic acid ester unit contained in the macromonomer was defined as a (counters).

Spectrum ¹H-NMR of the macromonomer measured using EX-270 'produced by JEOL, the area under the peak of protons from methylene groups bound to the ester bond of the (meth) acrylic ester unit was calculated as a, and the area under the terminal peak of the unsaturated ethylenic groups was defined as b.

The average number of terminal unsaturated ethylene groups per macromonomer molecule, defined as f, is calculated from Equation (II) below, using a and b.

f = b / (ax2) (II)

Moreover, F (%) defined as the percentage of the introduction of terminal unsaturated ethylene groups has been determined from Equation (III) below.

F = fx100 (4) Limit of adhesion of polymer microparticles to the polymerization reactor:

When a suspension of polymer microparticles formed by suspension polymerization (suspension polymerization with phase inversion) is collected from the polymerization reactor, the condition of the polymerization reactor has been visually inspected and the adhesion limit of the polymer microparticles has been determined according to the determination criteria shown in Table 1 below.

Table 1

<td>Symbol</td><td>Details of the determination</td>

<td>AND</td><td>Only a few polymer microparticles adhered to by the level of liquid in the polymerization reactor, there was no adhesion on the walls of the polymerization reactor.</td>

<td>B</td><td>Polymer microparticles adhered to the horizontal level the liquid in the polymerization reactor only as a thin band, there was no adhesion on the walls of the polymerization reactor.</td>

<td>C</td><td>Polymer microparticles adhered to the level liquid in the polymerization reactor as a thick band.</td>

<td>D</td><td>A large amount of polymer microparticles adhered to the liquid level in the polymerization reactor and to walls of a polymerization reactor.</td>

(5) Amount of residue on a polyethylene filter non-woven fabric (200 eyelets, mesh width 114pm) from a dispersion of polymer microparticles:

The suspension of polymer microparticles obtained in suspension polymerization was filtered using a polyethylene filtering non-woven fabric (200 mesh, mesh width 114, NIPPU strong mesh 200 mesh manufactured by NBC), the mass of residue such as polymer retained on the polyethylene filter cloth was measured after drying at 40 ° C for 24 hours and the ratio (% by mass) relative to the weight of the suspension of polymer microparticles used for filtration was calculated.

(6) Average particle size of polymer microparticles:

(i) 0.02g of the sample (dry powder of polymer microparticles obtained by removing the volatiles of the compounds by the method described in the Examples from the solution obtained by polymerization) was weighed, 20ml of n-heptane was added to it, and then the sample was mixed until a homogeneous hinge was obtained in n- heptane.

(ii) The n-heptane dispersion obtained in (i) above was subjected to a particle size distribution measurement using a laser diffraction scattering particle size distribution analyzer (MT-3000 manufactured by Nikkiso Co., Ltd.). n-Heptane was used as a circulating dispersion medium during the measurement. The n-heptane slurry was poured into the circulating dispersion medium, and the measurement was carried out after the sample had first been subjected to ultrasonic waves with a yield of 25 per minute by an ultrasonic homogenizer embedded in the apparatus. The refractive index of the dispersion medium and the sample was 1.39 and 1.53, respectively. The median diameter (pm) calculated from the volume distribution of the particle size was defined as the average particle size of the polymer microparticles.

(7) Degree of water absorption in polymer microparticles:

(i) The degree of water absorption in polymer microparticles was measured as follows using the equipment shown in FIG. 1.

In FIGS. 1, 1 means a burette equipped with a manifold for introducing air, 2a and 2b for a clamping cock, 3a, 3b and 3c for silicone tubes, 4 for a polytetrafluoroethylene tube, sealing material for polytetrafluoroethylene tube 4 and a branched tube, 6 means a funnel, 7 means a settling cylinder (supporting) with a large number of holes in the bottom, 8 means filter paper (ADVANTEC No. 2 filter paper manufactured by Advantec, diameter = 55mm), 9a and 9b means filter paper (both filter papers are ADVANTEC No 2 filter paper manufactured by Advantec, diameter = 55mm) for binding the sample (polymer microparticles), 10 means the cover (diameter = 55mm, weight = 9g), 11 means the pressure sensitive adhesive band,12 is a sample (polymer microparticles) and 13 is water after ion exchange.

(ii) Method of measurement:

(a) The section from the lower part of the branched burette tube 1, through the silicone tube 3c to the surface of the filter paper 8 placed in the perforated bottom of the settling cylinder 7 placed in the funnel 6 was filled with water after ion exchange and the tap at the bottom of the burette 1 and clamp 2b the branched tube is closed. Then, the cock 2 above the burette has been removed to provide water after ion exchange 13 to the upper part of the burette 1 by a silicon tube 3a mounted on the upper part of the burette 1. After the water has been supplied, the clamp 2a is closed and then the cock in the lower part of the burette and clamp 2b are opened. In this way, the section from the upper part of the burette 1 to the filter paper 8 has been filled with water after the ion exchange,

(b) Thereafter, the water surplus after ion exchange 13 separated from the surface of the filter paper 8 was removed from the surface of the filter paper using commercial kitchen paper, and then immediately read and recorded the scale (w1) on the burette 1.

(c) 0.1 to 0.2 g of sample to be measured [dry powder of polymer microparticles obtained by removing volatile compounds by the method described in the Examples from a solution of polymer microparticles obtained by polymerisation and held in a sealed glass bottle, a solid portion of the sample was measured by the method ( 1) above defined as NV (wt%)] were collected and precisely weighed (w0) and, as shown in FIG. 1 (c), placed uniformly in the central part of the filter paper 9a, another filter paper 9b was placed so as to cover the top of it and the sample 12 was fixed by combining the filter papers 9a and 9b by using a sticky tape 11.

(d) A sample 12 mounted between the filter papers 9a and 9b in (c) above was placed on filter paper 8 placed on the perforated bottom of the settling cylinder 7 together with the filter papers 9a and 9b, immediately afterwards the cover 10 was placed on them and after 30 minutes in this state, reading the scale (w2) on the burette 1 was made and recorded.

The total amount of ion exchange water absorbed by the sample and two sheets of filter paper 9a and 9b (total amount of water absorbed) (w3) was calculated from w3 = w2 - w.

(e) The same procedures as in (a) to (c) above were carried out except that the sample was not placed between filter papers 9a and 9b, the total amount of water after ion exchange 13 absorbed by the two sheets of filter paper 9a and 9b (total amount of absorbed water) (w4) was obtained and the degree of water absorption (times) by the sample (polymer microparticles) was calculated from Equation (IV) below.

The degree of water absorption by polymer microparticles (times) = (v₃ - in₄)/{in₀/ (NV / 100)} + 100 / NV (IV) (8) Average particle size of polymer microparticles in water saturated state to swell:

(i) 0.02g of sample (dry powder of polymer microparticles obtained by removing volatile components by the method described in the Examples from a suspension of polymer microparticles obtained by polymerization) were weighed, 20 ml of ion exchange water was added to the sample, mixed until a homogeneous suspension was obtained and then the suspension was left for 1 hour at 25 ° C so that the polymer microparticles could swell through the water after ion exchange until saturation.

(ii) The suspension in swollen saturated water obtained in (i) above was subjected to a particle size distribution measurement using a diffraction laser diffraction particle size distribution analyzer (MT3000 manufactured by Nikkiso Co., Ltd.). Water after ion exchange was used as a circulating disperser medium during the measurement. The suspension in water was poured into the circulating dispersion medium, the measurement was carried out after using ultrasonic waves with the output of 25 waves per minute in an ultrasonic homogenizer built into the apparatus. The refractive index of the dispersion medium and the sample was respectively

1.33 and 1.53. The median diameter (pm) calculated on the basis of the volumetric distribution of particle diameters was defined as the average size of polymer microparticles in the state of saturation with water to swell.

(9) The ratio of particles with a particle size of 150 μm or more in a saturated state with water to swell:

According to JIS K 0069-1992 (test method for screening chemical products), the ratio of particles with a particle size of 150 μm or more in a saturated water-swollen state was determined by the wet sieving residue method.

Specifically, 50g sample for measurement (dry powder polymer microparticles obtained by removing volatile compounds by the method described in Examples from a solution of polymer microparticles obtained by polymerization and stored in a sealed bottle, the ratio of solid in the sample was measured by method (1) above defined as NV (% mass)) was weighed, 50g of ethanol was added to the sample for fine grinding, then the whole was gradually poured into 3l of water after ion exchange under stirring, mixing was carried out for 60 minutes so that the water after ion exchange was absorbed into saturation to swell. Then, after checking that the polymer microparticles in the saturated state with water to swell are homogeneously dispersed, the aqueous solution was poured into a sieve with a 150 m mesh (diameter 70 mm) and pressed through it, the sieve residue was washed with a suitable amount of water after ion exchange and care was taken not to spill the residue. Then, the sieve with the residue was placed in a rotary dryer, dried at 150 ° C and then allowed to cool in the dryer, the sieve mass after cooling (total weight of the sieve and residue) (W1) was measured, the ratio of particles with a particle size of 150pm or more in the state of saturation with water for swelling [here and everywhere else, also called "the content of particles swollen with water (150pm or more)] was calculated

<td>ny</td><td colspan="3">from Equation (V) below.</td>

<td></td><td colspan="2">The content of particles swollen with water</td><td>(150pm or more)</td>

<td>(%</td><td>mass)</td><td></td><td></td>

<td></td><td>= {(Wi - w₀)/(in_r XNV / 100;</td><td>1 X 100</td><td>(V)</td>

<td>[in</td><td>equation, W0 means mass (g)</td><td>dry</td><td>sieves, W1 is whole</td>

the mass (g) of sieve and residue after drying, and WR is the mass (50g) of the sample (dried polymer microparticles). Example Production 1 [Production of the macromonomer (M-1)] (1) The substrate tank was loaded by the liquid mixture containing the monomer based on vinyl containing 75.0 parts by mass of lauryl methacrylate (a vinyl-based hydrophobic monomer), 25.0 parts by mass of acrylic acid (a vinyl-based hydrophilic monomer), 10.0 parts by mass of methyl ethyl ketone (polymerization solvent) and 0.45 parts mass tertiary butyl peroxide (radical polymerization catalyst).

(2) The temperature of the oil jacket of the 1000ml stirred reactor was maintained at 240 ° C, the liquid mixture containing the vinyl-based monomer was started from the substrate tank prepared in (1) above to the reactor, the liquid mixture containing the vinyl-based monomer was fed into the reactor and the extraction of the liquid reaction mixture from the reactor was carried out continuously so that the total amount of the liquid mixture containing the vinyl-based monomer was 580g and its average residence time was 12 minutes. During the continuous feeding of the liquid mixture containing the vinyl-based monomer, the temperature in the reactor was set at 235 ° C and the pressure inside the reactor was set to 1.1MPa. The reaction mixture extracted from the reactor is depressurized to 20 kPa and continuously fed to a thin film evaporation at 250 ° C to remove unreacted vinyl-based monomer or solvent, etc. by distillation, and then the macromonomer is collected from a thin film vaporizer. The vinyl-based monomer or solvent, etc. removed by evaporation from the thin film was cooled in a condenser and collected as a liquid distillate. The point at which it passes 60 minutes from the start of the liquid mixture containing the vinyl-based monomer, the temperature inside the reactor has stabilized at 235 ° C, has been defined as the starting point for the collection of the macromonomer from the thin film evaporator; the reaction was run for 48 minutes from the starting point of collection, and the macromonomer collected at this time was collected [here and everywhere else it will be called "macromonomer (M1)]. During this time, 2.34 kg of the liquid mixture containing the vinyl-based monomer was fed to the reactor, 1.92 kg of the macromonomer (M-1) was collected from the thin film evaporator and 0.39 kg of the distillate collected in the distillation tank.

(3) The distillate collected in (2) above was analyzed by gas chromatography (GC-390B manufactured by GL Sciences Inc.) which resulted in 100 parts by mass of the distillate containing 31.1 parts by mass of lauryl methacrylate,

16.4 parts by mass of acrylic acid and 52.5 parts by weight of solvent and others.

(4) (i) From the amount of liquid mixture containing a vinyl-based monomer fed to the reactor, a liquid mixture composition containing a vinyl-based monomer, the amount of macromonomer harvested (M-1), the amount of distillate collected and the distillate composition, the conversion rate of monomer-based reaction. vinyl was calculated to be 90.0% by mass and the composition of the macromonomer component units (M-1) was calculated as lauryl methacrylate: acrylic acid = 76.0: 24.0 (mass ratio).

(ii) The molecular weight of the macromonomer (M-1) harvested in (2) above was determined by the method described above, the weight average molecular weight (Mw) was 3,800 and the number average molecular weight (Mn) was 1,800.

(iii) The percentage of introduction of terminal unsaturated ethylene groups into the macromonomer (M-1) collected in (2) above was determined by the method described above and was 97%. Production examples 2 to 7 [Production of macromonomers (M-2) to (M-7)] (1) The same procedures as in (1) and (2) from Production Example 1 were carried out, except that the composition of a liquid mixture containing the vinyl-based monomer and the internal temperature of the reaction during polymerization have been changed as described in Table 2, thus giving macromonomers (macromonomer compositions) [the macromonomers obtained in this way are called macromonomers (M-2), (M-3), (M -4), (M5), (M-6) and (M-7)].

(2) For macromonomers (M-2) to (M-7) obtained in (1) above, the weight average molecular weight (Mw), number average molecular weight (Mn) and percentage of terminal unsaturated ethylene groups were determined by the methods described above, and the results are shown in Table 2 below.

Table 2

<td>Production Example No. (EP)</td><td>PE 1</td><td>PE 2</td><td>PE 3</td><td>PE 4</td><td>PE 5</td><td>PE 6</td><td>PE 7</td>

<td>Macromonomer code</td><td>M-1</td><td>M-2</td><td>M-3</td><td>M-4</td><td>M-5</td><td>M-6</td><td>M-7</td>

<td>[Monomer liquid composition (bulk parts)] Vinyl based monomer Lauryl methacrylate</td><td>75.0</td><td>65.0</td><td></td><td></td><td></td><td></td><td></td>

<td>Lauryl acrylate</td><td></td><td></td><td>90, 0</td><td>75.0</td><td>65.0</td><td></td><td></td>

<td>Stearyl methacrylate</td><td></td><td></td><td></td><td></td><td></td><td>75.0</td><td>75.0</td>

<td>Acrylic acid</td><td>25.0</td><td>35.0</td><td>10.0</td><td>25.0</td><td>35.0</td><td>25.0</td><td>25.0</td>

<td>Solvent Methyl ethyl ketone</td><td>10.0</td><td>10.0</td><td>10.0</td><td>10.0</td><td>10.0</td><td></td><td></td>

<td>n-Heptane</td><td></td><td></td><td></td><td></td><td></td><td>20.0</td><td>20.0</td>

<td>Polymerization catalyst¹⁾DPBP</td><td>0.3</td><td>0.3</td><td>0.3</td><td>0.3</td><td>0.3</td><td></td><td></td>

<td>DTHP</td><td colspan="2"></td><td></td><td></td><td colspan="2">0.2</td><td>0.2</td>

<td>[Polymerization temperature (° C)]</td><td>235</td><td>235</td><td>235</td><td>235</td><td>235</td><td>230</td><td>200</td>

<td>[Macromonomer] Molecular weight Molecular weight weight average</td><td>3800</td><td>4200</td><td>5400</td><td>5500</td><td>6100</td><td>5700</td><td>1410 0</td>

<td>The number average molecular weight</td><td>1800</td><td>2000</td><td>2500</td><td>2400</td><td>2500</td><td>3100</td><td>5200</td>

<td>Percentage introduction terminal unsaturated ethylene groups (%)</td><td>97</td><td>95</td><td>95</td><td>92</td><td>93</td><td>102</td><td>99</td>

1) Polymerization catalysts:

DPBP: di-tetr-butyl peroxide

DHTP: di-tetr-hexyl peroxide

Production Example 8 [Production of a macromonomer (M-8)] (1) A glass reactor equipped with a stirrer, a return condenser, two condensing funnels, a nitrogen inlet and a thermometer was loaded with 42.0 parts by mass of a hydrocarbon solvent (Isopar L manufactured by Isopar Exxon) and 20.0 parts by mass of toluene and the temperature inside the reactor was increased to 90 ° C by heating in a water bath under nitrogen flow. After stabilizing the internal temperature of the reactor at 90 ° C, 0.88 parts by mass of azobis 2-methylbutyronitrile and 1.5 parts by mass of acid were added to it.

3-mercaptopropionic acid, then a mixture containing a vinyl-based monomer containing 86.2 parts by mass of lauryl methacrylate and 7.8 parts by mass of 2-hydroxyethyl methacrylate were added dropwise while maintaining the internal temperature in the reactor at 90 ° C, thus radical polymerization was carried out, resulting in a carboxyl group-containing polymer solution as one end and having a hydroxyl group in the molecular chain. The vinyl-based monomer and the solvent used above were subjected to a dehydration process using a molecular sieve.

(2) 0.45 parts by mass of tetrabutylammonium bromide, 0.04 parts by mass of hydroquinone monomethyl ether and 2.21 parts by mass of glycolide methacrylate were added to the polymer solution (total amount) obtained in (1) above, the reaction was carried out at 110 ° C for 7 hours and prepared a solution containing a macromonomer having methacrylate groups at one end and hydroxyls in the molecular chain.

(3) 6.0 parts by mass of succinic anhydride was added at 110 ° C to a solution containing a macromonomer having a methacrylate group at one end obtained in (2) above (total amount), succinic acid reacted with the hydroxyl groups in the macromonomer. Immediately after addition of succinic anhydride, succinic anhydride particles floated in the reaction mixture, but all insoluble elements disappeared during the course of the reaction, heating was maintained at 110 ° C for 2 hours after the disappearance of all non-dissolved elements, followed by cooling, thus obtaining a solution containing a macromonomer having a methacrylic group at the end and carboxylic groups in the molecular chain (macromonomer) [here and everywhere further, this will be referred to as the "macromonomer (M-8)"].

(4) (i) When the solution containing the macromonomer (M-8) obtained in (3) above was heated to 200 ° C for 30 minutes, the residue (solid content) was 58.9% by mass.

(ii) Furthermore, regarding the macromonomer (M-8), when the acidity was measured by titration using 0.1N potassium hydroxide in ethanol, it was 32.6 mg KOH / g solid.

(iii) Moreover, when the molecular weight of the macromonomer (M-8) and the percentage of terminal unsaturated ethylene groups were measured by the methods mentioned above, the weight average molecular weight (Mw) was 17800, the number average molecular weight (Mn) was 8100, and the percent of introduction of terminal unsaturated ethylene groups was 83%.

Production Example 9 [Production of a non-macromonomer polymer (N-1)] (1) A reactor equipped with a stirrer, return condenser, thermometer and nitrogen inlet was loaded with 65.0 parts by mass of methyl ethyl ketone and heated in a water bath to an internal temperature of 78 ° C with nitrogen flow.

(2) Meanwhile, 85.0 parts by mass of lauryl acrylate, 15.0 parts by mass of acrylic acid, 2.5 parts by mass azobis

2-methylbutyronitrile and 22.5 parts by mass of methyl ethyl ketone were mixed to obtain a mixture containing a vinyl-based monomer. Moreover, separately from them, 17.0 parts by mass of methyl ethyl ketone and 4.2 parts by mass of mercaptopropionic acid were mixed to obtain the liquid of the chain transfer agent.

(3) After determining the internal temperature in the reactor at 78 ° C, 5.0 parts by mass of the mixture containing the vinyl-based monomer prepared in (2) above was added to the reactor, after 5 minutes an additional 120 parts by mass of the remaining monomer-based monomer mixture was started. vinyl and 21.2 parts by mass of the chain transfer agent. The instillation was carried out at a constant rate for 3 hours using a metering pump, at which time the internal temperature in the reactor remained at 78 ° C. After completion of the addition, the internal temperature in the reactor was increased to 80 ° C and maintained at 80 ° C for 3 hours, and then cooled, thus resulting in a solution containing a polymer that is not a macromonomer [here and everywhere referred to as "non-macromonomer polymer. (N-1) "].

(4) The residue (solids content) obtained with a solution containing a non-macromonomer polymer (N-1) obtained in (3) above was heated to 150 ° C for 1 hour at 50.3% by mass.

(ii) When the molecular weight of the non-macromonomer polymer (N-1) and the percentage of terminal unsaturated ethylene groups were measured by the methods mentioned above, the weight average molecular weight (Mw) was 4,400, the number average molecular weight (Mn) was 2,900, and the percentage the introduction of terminal unsaturated ethylene groups was 0%.

Production examples 10 and 11 [Production of non-bromomonomer polymers (N-2) and (N-3)] (1) The same procedures as (1) to (3) from Production Example 9 were carried out with the exception of the composition of the mixture containing a vinyl-based monomer changed as described in Table 3 below, solutions containing a polymer that is not a macromonomer were prepared [the polymers obtained in this way were called non-bromomonomer (N-2) and (N-3)] polymers.

(2) For non-macromonomer (N-2) and (N3) polymers obtained in (1) above, solid content, weight average molecular weight (Mw), number average molecular weight (Mn) and percentage of terminal unsaturations the ethylene groups were determined by the methods mentioned above and the results are shown in Table 3 below.

Table 3

<td>Production Example No.</td><td>Example production 9</td><td>Example production 10</td><td>Example production 11</td>

<td>Non-chromomonomer polymer code</td><td>N-1</td><td>N-2</td><td>N-3</td>

<td>[The composition of the monomer liquid (mass parts)] Vinyl based monomer Lauryl acrylate</td><td>85.0</td><td>75.0</td><td>65.0</td>

<td>Acrylic acid</td><td>15.0</td><td>25.0</td><td>35.0</td>

<td>Solvent Methyl ethyl ketone</td><td>22.5</td><td>22.5</td><td>22.5</td>

<td>Polymerization catalyst Azobis 2-methylbutyronitrile</td><td>2.5</td><td>2.5</td><td>2.5</td>

<td>[Polymerization temperature (° C)]</td><td>78</td><td>78</td><td>78</td>

<td>[Macromonomer] Molecular weight</td><td>4400</td><td>5200</td><td>5200</td>

<td colspan="2">Molecular weight by weight</td><td rowspan="2"></td><td rowspan="2"></td>

<td>average</td><td></td>

<td>Molecular weight average number</td><td>2900</td><td>3400</td><td>3400</td>

<td>Percentage of introduction of terminal unsaturated ethylene groups (%)</td><td>0</td><td>0</td><td>0</td>

Example 1 [Production of polymer microparticles (PA-1)] (1) The macromonomer (M-1) obtained in Production Example 1 was dissolved in n-heptane at 40 ° C, thus resulting in a solution containing a macromonomer (M-1) in concentration solids content [macromonomer (M-1)] 30.0 ± 0.5 mass% (liquid dispersion stabilizer). The solid content here, refers to the value calculated from the weight of the residue when the solution containing the macromonomer has been heated to 150 ° C for 1 hour.

(2) A polymerization reactor equipped with a mixing system consisting of a mixing blade with shattering blades and two vertical baffles, and then equipped with a thermometer, a return condenser and a nitrogen inlet was loaded

33.33 parts by mass of the macromonomer solution (M-1) prepared in (1) above [10.0 parts by mass of macromonomer (M-1)] and 33.67 parts by mass of n-heptane (total amount of nheptane in the polymerization reactor is 357, 0 parts by mass).

(3) Meanwhile, another reactor was loaded with 30.0 parts by mass of acrylic acid, 70.0 parts by mass of 2-acrylamido-2-methylpropane sulphonic acid, 9.80 parts by mass (corresponding to 4.0 moles with respect to 100 moles of mono-functional monomer based on vinyl) polyethylene glycol diacrylate (Aronix M-240 manufactured by Toagosei Co., Ltd., mean molecular weight 324) and 83.5 parts by mass of water after ion exchange, and after homogeneous dissolution by mixing at 30 ° C or lower, this liquid was neutralized by slowly adding 38.5 parts by mass of a 25% aqueous solution of ammonia at a temperature of 40 ° C or below, thus resulting in a liquid mixture containing a vinyl-based monomer (aqueous solution).

(4) After adjusting the rotational speed of the mixing blade in the polymerization reactor, the polymerization reactor was loaded with a liquid mixture containing a vinyl-based monomer (total amount) obtained in (3) above, stirring maintained at a temperature inside the polymerization reactor at 20 ° C thus resulting in a w / o solution in which the liquid dispersion containing the vinyl-based monomer (aqueous solution) was dispersed in the oil phase (the n-heptane phase) as droplets. Then, during this mixing operation, nitrogen gas was blown into the polymerization reactor to thereby remove oxygen from the polymerization reactor.

After the addition, the temperature inside the polymerization reactor increased, which indicates the start of polymerization. The internal temperature in the polymerization reactor reached the upper temperature (41 ° C) in a few minutes. Immediately after reaching the upper temperature, a solution in which 0.018 parts by mass of 69% by mass of a t-butyl hydroperoxide solution (oxidizing agent) (Perbutyl H69 produced by NOF Corporation, product dissolved in water) dissolved in 2.0 parts by mass of water after ion exchange has been added. The internal temperature in the polymerization reactor immediately increased to 46 ° C and then decreased. The reaction liquid from the polymerization reactor was cooled to room temperature, thus resulting in a suspension of polymer microparticles (PA-1). The internal temperature in the polymerization reactor reached the upper temperature (41 ° C) in a few minutes. Immediately after reaching the upper temperature, a solution in which 0.018 parts by mass of 69% by mass of a t-butyl hydroperoxide solution (oxidizing agent) (Perbutyl H69 produced by NOF Corporation, product dissolved in water) dissolved in 2.0 parts by mass of water after ion exchange has been added. The internal temperature in the polymerization reactor immediately increased to 46 ° C and then decreased. The reaction liquid from the polymerization reactor was cooled to room temperature, thus resulting in a suspension of polymer microparticles (PA-1). The internal temperature in the polymerization reactor reached the upper temperature (41 ° C) in a few minutes. Immediately after reaching the upper temperature, a solution in which 0.018 parts by mass of 69% by mass of a t-butyl hydroperoxide solution (oxidizing agent) (Perbutyl H69 produced by NOF Corporation, product dissolved in water) dissolved in 2.0 parts by mass of water after ion exchange has been added. The internal temperature in the polymerization reactor immediately increased to 46 ° C and then decreased. The reaction liquid from the polymerization reactor was cooled to room temperature, thus resulting in a suspension of polymer microparticles (PA-1). 018 parts by mass 69% by weight t-butyl hydroperoxide solution (oxidizing agent) (Perbutyl H69 produced by NOF Corporation, product dissolved in water) dissolved in 2.0 parts by mass of water after ion exchange has been added. The internal temperature in the polymerization reactor immediately increased to 46 ° C and then decreased. The reaction liquid from the polymerization reactor was cooled to room temperature, thus resulting in a suspension of polymer microparticles (PA-1). 018 parts by mass 69% by weight t-butyl hydroperoxide solution (oxidizing agent) (Perbutyl H69 produced by NOF Corporation, product dissolved in water) dissolved in 2.0 parts by mass of water after ion exchange has been added. The internal temperature in the polymerization reactor immediately increased to 46 ° C and then decreased. The reaction liquid from the polymerization reactor was cooled to room temperature, thus resulting in a suspension of polymer microparticles (PA-1).

(6) (i) A portion of the dispersion of polymer microparticles (PA-1) obtained in (5) above was taken as a sample, photographed at 450 magnification using a digital microscope (VH-6000 produced by Keyence Corporation) as in FIG. 2. As can be seen in the photograph of FIG. 2, the polymer microparticles (PA-1) obtained in (5) above were formed from a group of spherical polymer microparticles having a particle size distribution centralized around 40μm, and aggregates (secondary particles) in which several polymer microparticles would be glued were not observed.

(ii) Moreover, when the polymer microparticle dispersion (PA1) was selected from the polymerization reactor, the adhesion of the polymer microparticles to the interior of the polymerization reactor was examined visually; only a few polymer microparticles adhered to the ambient liquid level inside the polymerization reactor and there was no adhesion of the polymer microparticles to the walls of the polymerization reactor.

(iii) A portion of the dispersion of polymer microparticles (PA-1) obtained in (5) above was taken as a sample, the amount of residue in the cake on a polyethylene filter (200 mesh, mesh 114pm) was measured by the method mentioned above and the lowest value was 0.028% by mass ( 278 ppm).

(iv) A portion of the dispersion of polymer microparticles (PA-1) obtained in (5) above was taken as a sample, the solution was heated to 110 ° C for 1 hour, dried polymer microparticles (PA-1) were collected and stored in sealed glass bottles. When the average particle size (dried) and the degree of water absorption were measured by the methods mentioned above, the average particle size was 42.4pm and the water absorption rate was 16.8 times.

(7) (i) Furthermore, the portion of the suspension obtained in (5) above was taken as a sample, the suspension was heated to 110 ° C for 1 hour, the dried polymer microparticles (PA-1) were collected and then loaded into a large amount of water after ion exchange and left at 25 ° C for 1 hour to allow them to swell up to saturation with water and then photographed at 450 × magnification using a digital microscope (VH-6000 produced by Keyence Corporation) as in FIG. 3. As can be seen in the photograph of FIG. 3, particles saturated with water to swell polymer microparticles (PA-1) obtained in (5) above have a particle size distribution centralized around 100μη.

(ii) The average particle size of the polymeric microparticles (PA-1) collected in (i) above in a saturated water-swollen state was tested by the methods mentioned above and was 95.2μη.

Examples 2 to 8 [Method for producing polymer microparticles (PA-2) to (PA-8)] (1) The same procedures as in (1) to (5) of Example 1 are used except that instead of a macromonomer (M-1) ) a macromonomer (M-2) to (M-5) was used as the dispersion stabilizer in the amount given in

Table 4 below (Examples 2 to 5) or macromonomer (M-5) or (M-1) and other dispersion stabilizer (sorbitan monooleate, RHEODOL AO-10 manufactured by Kao Corporation, emulsifier for w / o emulsions, HLB = 4.3) were used in the amount given in Table 4 below (Examples 7 and 8) and in this way polymeric microparticles (PA-2) to (PA8) were produced.

(2) When the suspensions of polymer microparticles (PA-2) to (PA-8) obtained in (1) above were selected from the polymerization reactor, the adhesion of polymer microparticles to the interior of the polymerization reactor was examined visually; only a few or a thin band of polymer microparticles adhered to the liquid level in the polymerization reactor and no adhesion to the walls of the polymerization reactor was observed.

(3) For suspensions of polymeric microparticles (PA2) to (PA-8) obtained in (1) above, the amount of residue in the filter cake on a polyethylene filter (200 meshes, mesh 114μπι), average particle size (dry) of polymer microparticles ( PA-2) to (PA-8), the degree of water absorption, the average particle size in the saturated water state for swelling were determined by the methods described above in Example 1 and collected in Table 4 below.

Comparative Examples 1 to 8 [Production of polymer microparticles (PB-1) to (PB-8)] (1) The same procedures as in (1) to (5) in Example 1 were used except that the macromonomer (M-1) replaced with one of the non-macromonomer polymers (N-1) to (N-3) obtained in Production Examples 9 to 11 as the dispersion stabilizer in the amount shown in Table 5 below (Comparative Examples 1 to

3) or non-macromonomer (N-3) and another dispersion stabilizer (sorbitan monooleate, RHEODOL AO-10 produced by

Kao Corporation, w / o emulsion emulsifier, HLB = 4.3) in the amount shown in Table 5 below (Comparative Examples 5 and 7) or two types of other dispersion stabilizers [dispersion stabilizer type of triblock copolymer (HYPERMER B-246 produced by Uniqema, polymer emulsifier solution for w / o emulsion) and sorbitan monooleate (RHEODOL AO10 produced by Kao Corporation, emulsifier for w / o emulsions, HLB = 4.3)] were used in the amounts shown in Table 5 below (Comparative Examples 4, 6 and 8) and thus suspensions of polymer microparticles (PB-1) to (PB-8) were produced.

(2) It has been found that in Comparative Examples 1 to 4, large aggregates of aggregates have been formed at the same time as the beginning of the polymerization and a suspension of polymer microparticles can not be obtained.

(3) (i) In Comparative Examples 5 to 8, suspensions of polymer microparticles (PB-5) to (PB-8) can be produced, but when the suspension in the oil immediately after the polymerization and the suspension in saturation state for swelling obtained by separation and collecting polymer microparticles from the slurry, drying them and then loading them into water were examined using a microscope in the same manner as in Example 1, a large number of aggregates to which aggregates themselves were formed and in both: suspension in oil and suspension in saturation state swelling, aggregates were created that could not be redispersed to individual primary particles.

(ii) With respect to Comparative Examples 5 to 8 the state of adhesion to the polymerization reactor, the amount of residue in the filter cake on a polyethylene filter (200 mesh, mesh 114 μm) from the polymer microparticle suspensions (PB-5) to (PB-8), mean size particles of (dry) polymer microparticles (PB-5) to (PB-8), the degree of water absorption and the average particle size in saturation state for swelling were determined by the methods mentioned above described in Example 1 and collected in Table 5 below.

Table 4

<img file="PL2048165T3_D0001.tif" />

<td>Diacrylate</td><td>9.8</td><td>9.8</td><td>9.8</td><td>9.8</td><td>9.8</td><td>9.8</td><td>9.8</td><td>9.8</td>

<td>polyethylene</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td>

<td>ester</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>[Stabilizer</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>dispersion]</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Stabilizer</td><td>M-1</td><td>M-2</td><td>M-3</td><td>M-4</td><td>M-5</td><td>M-5</td><td>M-5</td><td>M-1</td>

<td>Persia (1)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Type (macro type</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>monomer)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Amount used (parts</td><td>10</td><td>10</td><td>10</td><td>10</td><td>10</td><td>8.0</td><td>1.2</td><td>1.2</td>

<td>mass)</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td></td><td></td><td></td>

<td>Stabilizer</td><td></td><td></td><td></td><td></td><td></td><td>AO-</td><td>AO-</td><td>AO-</td>

<td>Persia (2)</td><td></td><td></td><td></td><td></td><td></td><td>10</td><td>10</td><td>10</td>

<td>Type¹)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Amount used (parts</td><td></td><td></td><td></td><td></td><td></td><td>2.0</td><td>8.0</td><td>8.0</td>

<td>mass)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>[Microparticles</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>limerowe]</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Degree of adhesion</td><td>AND</td><td>B</td><td>B</td><td>AND</td><td>B</td><td>B</td><td>AND</td><td>AND</td>

<td>microparticles after</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>limerowych²)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Amount remaining</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>in the cake</td><td>0.0</td><td>0.0</td><td rowspan="2">_-3)</td><td>0.1</td><td>0.0</td><td>0.1</td><td>0.3</td><td>0.0</td>

<td rowspan="2">on the film</td><td rowspan="2">28</td><td rowspan="2">20</td><td rowspan="2">02</td><td rowspan="2">06</td><td rowspan="2">51</td><td rowspan="2">24</td><td rowspan="2">19</td>

<td></td>

<td>polyethylene</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>wym (% by mass)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Medium size</td><td>42,</td><td>33,</td><td>59,</td><td>36,</td><td>34,</td><td>29</td><td>21</td><td>19</td>

<td>particles (pm)</td><td>4</td><td>1</td><td>1</td><td>3</td><td>4</td><td>3</td><td>2</td><td>4</td>

<td>Degree of absorption</td><td>16</td><td>17</td><td>16</td><td>16</td><td>16</td><td>16</td><td>17</td><td>17</td>

<td>water (times)</td><td>8</td><td>1</td><td>2</td><td>7</td><td>9</td><td>8</td><td>5</td><td>9</td>

<td>Medium size particles in stock</td><td>95,</td><td>WHAT What</td><td>142</td><td>77,</td><td>72,</td><td>62,</td><td>42,</td><td>42,</td>

<td>saturation with water to</td><td>2</td><td>4</td><td>, 0</td><td>0</td><td>6</td><td>9</td><td>2</td><td>5</td>

<td>swellings (μη)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

1) Dispersion stabilizer:

AO-10: sorbitan monooleate (RHEODOL AO-10 manufactured by Kao Corporation)

2) The degree of adhesion of polymer microparticles to the polymerization reactor

3) Most of the particles remained in the filter cake on the polyethylene filter due to the large primary particles

Table 5

<td rowspan="2"></td><td colspan="8">Comparative Example</td>

<td>1</td><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td><td>8</td>

<td>The microparticle code</td><td>PB</td><td>PB</td><td>PB</td><td>PB</td><td>PB</td><td>PB</td><td>PB</td><td>PB</td>

<td>polymer</td><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td><td>8</td>

<td>[Monomer composition</td><td>thirty,</td><td>thirty,</td><td>thirty,</td><td>thirty,</td><td>thirty,</td><td>thirty,</td><td>thirty,</td><td>thirty,</td>

<td>(mass parts)]</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td>

<td>Acrylic acid</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Acid 2-</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>acrylamido-2-</td><td>70</td><td>70</td><td>70</td><td>70</td><td>70</td><td>70</td><td>70</td><td>70</td>

<td>metylopropanosulfo-</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td>

<td>new</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>The glycine diacrylate</td><td>9.8</td><td>9.8</td><td>9.8</td><td>9.8</td><td>9.8</td><td>9.8</td><td>9.8</td><td>9.8</td>

<td>or polyethylene</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td>

<td>[Disk stabilizer</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>persia]</td><td>N-1</td><td>N-2</td><td>N-3</td><td>B-</td><td>N-3</td><td>B-</td><td>N-3</td><td>B-</td>

<td>Stabilizer</td><td></td><td></td><td></td><td>246</td><td></td><td>246</td><td></td><td>246</td>

<td>Persia (1) Type¹)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Amount used (parts</td><td>10</td><td>10</td><td>10</td><td>10</td><td>8, 0</td><td>8, 0</td><td>1.2</td><td>1.2</td>

<td>mass)</td><td>0</td><td>0</td><td>0</td><td>0</td><td></td><td></td><td></td><td></td>

<td>Stabilizer</td><td></td><td></td><td></td><td></td><td>AO-</td><td>AO-</td><td>AO-</td><td>AO-</td>

<td>Persia (2) Type¹)</td><td></td><td></td><td></td><td></td><td>10</td><td>10</td><td>10</td><td>10</td>

<td>Amount used (parts mass)</td><td></td><td></td><td></td><td></td><td>2.0</td><td>2.0</td><td>8.0</td><td>8.0</td>

<td>[Microparticles poly</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>mer]</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Degree of adhesion</td><td>_-3)</td><td>_-3)</td><td>_-3)</td><td>_-3)</td><td>D</td><td>C</td><td>C</td><td>C</td>

<td>polymer copolymers</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>-sectoral²)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Amount of residue</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>in the filter cake -</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>on the filter</td><td>_-3)</td><td>_-3)</td><td>_-3)</td><td>_-3)</td><td>_-4)</td><td>_-4)</td><td>_-4)</td><td>_-4)</td>

<td>ethylene (% ma-</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Owls)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Medium size</td><td>_-3)</td><td>_-3)</td><td>_-3)</td><td>_-3)</td><td>34,</td><td>29</td><td>18</td><td>18</td>

<td>particles (pm)</td><td></td><td></td><td></td><td></td><td>5</td><td>5</td><td>0</td><td>9</td>

<td>Degree of absorption</td><td>_-3)</td><td>_-3)</td><td>_-3)</td><td>_-3)</td><td>17</td><td>16</td><td>16</td><td>15</td>

<td>water (times)</td><td></td><td></td><td></td><td></td><td>8</td><td>1</td><td>9</td><td>5</td>

<td>Medium size</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>particles in stock</td><td>_-3)</td><td>_-3)</td><td>_-3)</td><td>_-3)</td><td>72,</td><td>62,</td><td>42,</td><td>42,</td>

<td>saturation with water to</td><td></td><td></td><td></td><td></td><td>6</td><td>9</td><td>2</td><td>5</td>

<td>bulges (pm)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

1) Dispersion stabilizer:

<td>N-1: polymer</td><td>non-macromonomer</td><td>made</td><td>in</td><td>example</td>

<td>Production 9</td><td></td><td></td><td></td><td></td>

<td>N-2: polymer</td><td>non-macromonomer</td><td>made</td><td>in</td><td>example</td>

<td>Production 10</td><td></td><td></td><td></td><td></td>

<td>N-3: polymer</td><td>non-macromonomer</td><td>made</td><td>in</td><td>example</td>

Production 11

B-246: type of triblock copolymer (HYPERMER B-246 produced by Uniqema)

AO-10: sorbitan monooleate (RHEODOL AO-10 manufactured by Kao Corporation)

2) The degree of adhesion of polymer microparticles to the polymerization reactor

3) Large aggregates formed at the same time as the start of polymerization, a suspension of polymer microparticles can not be obtained

4) Lots of particle aggregates, polyethylene filter blocked, filtration can not be carried out

As can be seen in the results of Examples 1 to 8 in Table 4 above, Examples 1 to 8, in which hydrophilic (water-swollen) polymer microparticles were produced by phase inversion-suspension polymerization using a macromonomer having unsaturated radical polymerizable groups on the ends of the polymer derivative from vinyl-based monomer [especially, macromonomers (M-1) to (M5)] as a dispersion stabilizer, polymer microparticles having a suitable particle size in the order of a few μm to several tenths of a pm can be obtained with a homogeneous particle size,having excellent water absorption capacity and capable of being dispersed as individual primary particles without forming secondary particles as a result of aggregation of the particles together in water while maintaining a spherical shape when swollen by water absorption.

and the original aggregation free particles and having a predicted suitable and homogeneous particle size could not be obtained (Comparative Examples 5 to 8) Example 9 [Production of polymer microparticles (PA-9)] (1) Macromonomer (M-1) obtained in Production Example 1 was removed in n-heptane at 40 ° C, thus giving a solution containing a macromonomer (M-1) with a solid content concentration [macromonomer (M-1)] 30.0 ± 0.5 mass% (liquid dispersion stabilizer) ). The solid content described herein is the value calculated from the residual mass when the solution containing the macromonomer has been heated to 150 ° C for 1 hour.

(2) A polymerization reactor equipped with a mixing mechanism consisting of a mixing blade with shattering blades and two vertical divisions, and subsequently equipped with a thermometer, a return condenser and a nitrogen inlet being loaded

2.33 parts by mass of the macromonomer solution (M-1) prepared in (1) above [0.70 parts by mass of the macromonomer (M-1)], 1.50 parts by mass of sorbitan monooleate (RHEODOL AO-10 produced by Kao Corporation, emulsifier) for w / o emulsions, HLR = 4.3) and 162.9 parts by mass of n78 heptane (polymerization solvent) (total amount of nheptane in the polymerization reactor 164.5 parts by mass).

(3) Meanwhile, another reactor was loaded with 100.0 parts by mass of acrylic acid, 7.83 parts by mass (corresponding to 1.74 mol per 100 moles acrylic acid) of polyethylene glycol diacrylate (Aronix M-240 manufactured by Toagosei Co., Ltd. , mean molecular weight 324) and 88.0 parts by mass of water after ion exchange, and then everything was dissolved homogeneously by stirring at 30 ° C or lower, the liquid was neutralized by slow addition

70.8 parts by mass of a 25% aqueous ammonia solution at a temperature of 40 ° C or below, thus resulting in a liquid mixture containing a vinyl-based monomer (aqueous solution).

(4) After adjusting the rotation speed of the mixing blade of the polymerization reactor, the polymerization reactor was loaded with 30% by mass (total amount) of the liquid mixture containing the vinyl-based monomer obtained in (3) above, followed by a solution in which 0.098 parts by mass of ammonium persulfate was dissolved in 1.18 parts by mass of water after ion exchange, thus resulting in a w / o system in which the liquid mixture containing the vinyl-based monomer (aqueous solution) was dispersed in the oil phase (n-heptane) in the form of droplets. In this process, the mixing was carried out while maintaining the internal temperature in the polymerization reactor at 20 ° C, and the nitrogen was pressed into the polymerization reactor to thereby remove oxygen from the inside of the polymerization reactor.

(5) At the point when 2 hours had passed after the addition of 30% by mass of the liquid mixture containing the vins-based monomer, the first stage of polymerization was started by adding

1.74 parts by mass of an aqueous solution of the reducing agent (a solution of 0.074 parts by mass of sodium bisulfite dissolved in 1.67 parts by mass of water after ion exchange, in which iron sulphate dissolved at a concentration of 800ppm). After addition of the reducing agent solution, the internal temperature in the polymerization reactor immediately increased and it was confirmed that the polymerization started. The internal temperature in the polymerization reactor reached the upper limit (39 ° C) in a few minutes. Immediately after reaching the upper temperature, 1.27 parts by mass of 386 ppm of an aqueous solution of t-butyl peroxide (oxidizing agent) was added. Immediately thereafter, the internal temperature in the polymerization reactor increased to 41 ° C and then decreased.

(6) After cooling the reaction liquid in a polymerization reactor to 23 ° C or below, the polymerization reactor was loaded with the remainder of the liquid mixture containing vinyl-based monomer (70% by mass of total amount) and then with a solution of 0.142 parts by mass of ammonium persulfate at 1.69 parts by mass of water after ion exchange. After confirming that the internal temperature in the polymerization reactor was 20 ° C, the second polymerization step was started by adding 2.51 parts by mass of an aqueous reducing agent solution (0.106 parts by mass of sodium bisulfite in 2.40 parts by mass of water after ion exchange with the addition of iron sulphate) at a concentration of 800ppm). After adding the aqueous solution of the reducing agent, the internal temperature in the polymerization reactor immediately increased which confirmed the start of the polymerization. The internal temperature in the polymerization reactor reached the upper temperature (37 ° C) in several minutes. Immediately after reaching the upper temperature, it was added

1.75 parts by mass of 0.876% by weight aqueous solution of t-butyl peroxide (oxidising agent). The internal temperature in the polymerization reactor immediately increased to 50 ° C and then decreased. The reaction liquid in the polymerization reactor was cooled to room temperature, thus resulting in a suspension of polymer microparticles (PA-9).

(7) (i) A portion of a suspension of polymer microparticles (PA-9) obtained in (6) above was taken as a sample and tested at 450 magnification using a digital microscope (VH-6000 produced by Keyence Corporation); the sample was constructed from a group of spherical polymer microparticles having a particle size distribution centralized around 20pm, and aggregates (secondary particles) in which several polymer microparticles were glued were not observed.

(ii) Moreover, when the polymer microparticle dispersion (PA9) was selected from the polymerization reactor, the adhesion of polymer microparticles to the interior of the polymerization reactor was visually examined; only a few polymer microparticles adhered to the vicinity of the liquid level in the polymerization reactor and no polymer microparticles adhered to the walls of the polymerization reactor were observed.

(iii) A portion of a suspension of polymer microparticles (PA-9) obtained in (6) above was taken as a sample, the amount of residue in the filter cake on a polyethylene filter (200 eyes, mesh 114m) was measured by the methods mentioned above and its lowest value was 1, 7% by mass.

(8) (i) A portion of the polymer microparticles suspension (PA-9) obtained in (6) above was taken as a sample, the suspension was heated to 110 ° C for 1 hour, and then the dried polymer microparticles (PA-9) were collected and stored in a sealed glass bottle. When the average particle size (dry) and the water absorption rate were measured by the methods mentioned above, in the same manner as in Example 1, the average particle size was 22.0 μm and the water absorption rate was 22.0 times.

(ii) Furthermore, a portion of the suspension obtained in (6) above taken as a sample was heated to 110 ° C for 1 hour, the dried polymer microparticles (PA-9) were collected in this manner, and were then loaded into a large volume of water after Ion exchange and left at 25 ° C for 1 hour to bring them to saturation state for swelling, and then their condition was examined at 450 times magnification using a digital microscope (VH6000 manufactured by Keyence Corporation), the sample was constructed from primary spherical particles in a saturated water state to swell, the average particle size in the saturated state to swell was 45.5 μm.

(9) Based on the results of Example 9, it was found that when hydrophilic (water-swollen) polymer microparticles were produced by suspension phase-inversion polymerization using a macromonomer having unsaturated radical polymerizable groups at the ends of the vinyl-based monomer-derived polymer [especially the macromonomer (M-1)] as a dispersion stabilizer, even when the polymerization has been carried out in two stages, polymer microparticles having a suitable particle size of several μm or several tenths of a μη can be obtained, this size is uniform,having excellent water-absorbency properties and capable of being well dispersed as individual primary particles without forming secondary particles by aggregating the particles together and retaining a spherical shape in a water-swollen state.

Comparative Example 9 [Production of polymer microparticles (PB-9)]

When a suspension of polymer microparticles (PB-9) was produced according to the same procedures as in (1) to (6) in Example 9 except that only 2.20 parts by mass of sorbitan monooleate (RHEODOL AO-10 manufactured by Kao Corporation, an emulsifier for w / o emulsion, HLB = 4.3) was used as a dispersion stabilizer, and 164.5 parts by mass of n-heptane were loaded as a polymerization solvent, large aggregates were formed at the start of the second polymerization stage, and the polymer microparticle it could be produced.

Example 10 [Production of polymer microparticles (PA-10)] (1) The macromonomer (M-1) obtained in Production Example 1 was dissolved in n-heptane at 40 ° C, thus resulting in a solution containing a macromonomer (M-1) in solid content concentration [macromonomer (M-1)] 30% ± 0.5 mass% (liquid dispersion stabilizer). The solid content described herein is the value calculated from the weight of the residue when the solution containing the macromonomer has been heated to 150 ° C for 1 hour.

(2) A polymerization reactor equipped with a mixing mechanism consisting of a mixing blade with shattering blades and two vertical partitions, and subsequently equipped with a thermometer, return condenser and nitrogen inlet was loaded with 16.7 parts by mass of a solution containing a macromonomer (M-1) prepared in (1) above [5.0 parts by mass of the macromonomer (M-1)] and 388.3 parts by mass of n-heptane (total amount of n-heptane in the polymerization reactor 400.0 parts by mass).

(3) Meanwhile, another reactor was loaded with 100.0 mass units of acrylic acid, 14.8 mass parts (corresponding to 2.5 moles with respect to 100 moles monofunctional monomer based on vinyl) polyethylene glycol diacrylate (Aronix M-243 manufactured by Toagosei Co., Ltd., mean molecular weight 425) and 95.0 parts by mass of water after ion exchange, and then dissolved by stirring at 30 ° C or below, this liquid was neutralized by slow addition of 70.8 parts by mass of 25% aqueous ammonia solution at a temperature of 40 ° C or below, thus resulting in a liquid mixture containing a vinyl-based monomer.

(4) After adjusting the rotational speed of the mixing blade of the polymerization reactor, the polymerization reactor was loaded with a liquid mixture containing a vinyl-based monomer (total amount) obtained in (3) above, mixing was carried out while maintaining the temperature inside the polymerization reactor at 20 ° C, yielding this method w / o solution in which the liquid mixture containing the vinyl-based monomer (aqueous solution) was dispersed in the oil phase (the n-heptane phase) in the form of droplets. Furthermore, during the mixing operation, the nitrogen was pressed into the polymerization reactor to remove oxygen from the inside of the polymerization reactor (aqueous solution).

(5) At the point where it was 1 hour and 50 minutes after the addition of a liquid mixture containing a wax-based monomer, 3.11 parts by mass of 0.60% by mass of an aqueous solution of t-butyl hydroperoxide (oxidizing agent, abbreviated as TBHP) (Perbutyl H produced by NOF Corporation, 69% aqueous TBHP solution diluted with water to a 0.60% THBP concentration) was charged to the polymerization reactor. At the point where 2 hours elapsed from the addition of the liquid mixture containing the vinyl-based monomer, a solution was added in which 0.18 parts by mass of sodium bisulfite (reducing agent) was dissolved in 2.87 parts by mass of water after ion exchange. After the addition, the internal temperature in the polymerization reactor immediately increased, which confirmed the start of the polymerization. The internal temperature in the polymerization reactor reached the upper temperature (54 ° C) per minute. Immediately after reaching the upper temperature, it was added

3.19 parts by mass of 0.23 mass% aqueous solution of tert-butyl hydroperoxide (oxidizing agent). The internal temperature in the polymerization reactor increased immediately to 64 ° C and then decreased. The reaction liquid inside the polymerization reactor was cooled to room temperature, thus resulting in a suspension (suspension in oil) of the polymer microparticles (PA-10).

(6) (i) A portion of a suspension of polymer microparticles (PA-10) obtained in (5) above was taken as a sample and then photographed at 420 x magnification using a digital microscope (KH-3000 manufactured by HIROX Co., Ltd.) as in the photo of FIG. 4. As can be seen in the photograph of FIG. The 4 polymer microparticles (PA-10) obtained in (5) above were formed from a group of spherical polymeric microparticles having a particle size distribution centralized around 20pm, and aggregates (secondary particles) in which several polymer microparticles would be tackled were not observed.

(ii) Furthermore, when the polymer microparticle dispersion (PA10) was selected from the polymerization reactor, the adhesion of polymer microparticles to the interior of the polymerization reactor was visually examined; only a few polymer microparticles adhered to the liquid level inside the polymerization reactor, no adhesion to the walls of the polymerization reactor was observed.

(iii) A portion of the suspension of polymer microparticles (PA-10) obtained in (5) above was taken as a sample, the amount of residue in the filter cake on a polyethylene filter (200 eyes, mesh 114m) was measured by the method mentioned above and its value was 0.067% mass (670ppm).

(7) The rest of the polymer microparticle suspension (PA-10) obtained in (5) above was placed in a glass vessel equipped with an anchor type mixing blade and a water separator having a return condenser, the glass container was placed in an oil bath and heated at an external temperature of 125 ° C in order to heat the volatile compounds inside the glass container azeotropically in the aresotropic way, and the water separated in this way to drain through the water separator. Dehydration was terminated when 95% by mass of water contained in the polymer microparticles dispersion (PA-10) contained in the glass vessel was discharged, volatile compounds such as n-heptane were subsequently removed by drying and heating under low pressure, and thus a powder was obtained polymer microparticles (PA-10).

(8) (i) When the average particle size (dry) and water absorption rate of the polymer microparticles powder (PA-10) obtained in (7) above was measured by the methods mentioned above, the average particle size was 18.0pm and the water absorption rate was 18.5 times.

(ii) The polymer microparticle powder (PA-10) obtained in (7) above was loaded into a large amount of excess water after ion exchange and left at 25 ° C for 1 hour to allow the particles to swell to saturation; in this state, they have been photographed at 420 times magnification using a digital microscope such as in (i) from (6) above, as shown in FIG. 5, and the polymer microparticles (PA-10) in the water-swollen state obtained in (7) above retained their spherical shape and had a particle size distribution centralized around 40 .mu.m.

(iii) The average particle size in the water saturated state for swelling the polymer microparticles powder (PA-10) obtained in (7) above was measured by the method mentioned above and was 38.3pm.

(iv) With respect to the polymer microparticle powder (PA10) obtained in (7) above, the ratio of particles having a particle size of 150 μm or greater in water saturated state to swell was measured by the method described above and the ratio of coarse particles having a particle size of 150 μm or more in the state Water saturation to swell had a very low value of 0.07% by mass and the particle size was uniform.

Examples 11 and 12 [Production of polymer microparticles (PA11) and (PA-12)] (1) When the suspension (type of suspension in oil) of polymer microparticles (PA-11) and polymer microparticles (PA-12) was produced according to the same procedures as in (1) to (5) of Example 10, except that the dispersion stabilizer has been changed to those shown in Table 6, the polymer microparticle suspension can be produced stably in the same manner as in Example 10.

(2) (i) When a portion of each suspension of polymer microparticles (PA-11) and a suspension of polymer microparticles (PA-12) obtained in (1) above was taken as a sample and examined at 420 times magnification using the same digital microscope as the one used in Example 10, polymer microparticles (PA-11) were formed from a group of spherical polymer microparticles having a particle size distribution centralized around 20pm, polymer microparticles (PA-12) were also formed from a group of spherical polymer microparticles having a particle size distribution centralized around 20pm, and aggregates (secondary particles) in which several polymer microparticles were glued were not observed in any polymer microparticles.

(ii) Moreover, when each polymer microparticle dispersion (PA-11) and polymer microparticle dispersion (PA-12) were selected from polymerization reactors, the adhesion of polymer microparticles to the interior of the polymerization reactor was visually examined and in both cases only a few polymer microparticles adhered to around the liquid level inside the polymerization reactor and there is no adhesion of the polymer microparticles to the walls of the polymerization reactor.

(iii) A portion of each suspension of polymer microparticles (PA11) and a suspension of polymer microparticles (PA-12) obtained in (1) above was taken as a sample, the amount of residue in the filter cake on a polyethylene filter (200 eyelets, mesh 114μπι) was measured by said method above, it was a very small amount of 0.011% by mass of polymer microparticles (PA-11) and 0.019% by mass of polymer microparticles (PA-12).

(3) The remainder of each suspension of polymer microparticles (PA-11) and a suspension of polymer microparticles (PA-12) obtained in (1) above was treated in the same manner as in (7) of Example 10 to obtain polymer microparticles powder (PA-11 ) and polymer microparticles (PA-12).

(4) (i) When the average particle size (dry) and water absorption rate of the polymer microparticles powder (PA-11) and polymer microparticles (PA-12) obtained in (3) above were measured by the methods mentioned above, the average particle size of polymer microparticles (PA-11) was 19.4μm, and the degree of water absorption was 19.4 times, and the average particle size of polymer microparticles (PA-12) was 20.6μm, and the degree of water absorption was 20.1 times.

(ii) A powder of polymer microparticles (PA-11) and polymer microparticles (PA-12) obtained in (3) above was loaded into a large volume of excess water after ion exchange and left at 25 ° C for 1 hour to allow the particles to swell to saturation state, and then this condition was examined at 420 times magnification using the same digital microscope as in Example 10; in both cases the spherical shape has been preserved, polymer microparticles (PA-11) in water saturated state to swell have a polymer distribution around 45μm centralized and polymer microparticles (PA-12) in water saturated state to swell have a centralized particle size distribution around 50 micron.

(iii) The average particle size in water-saturated state for swelling each polymer microparticles powder (PA-11) and polymer microparticles (PA-12) obtained in (3) above was measured by the method mentioned above and was 46.2μm for polymer microparticles (PA) -11) and 49.7 for polymer microparticles (PA-12).

(iv) For each powder of polymer microparticles (PA-11) and polymer microparticles (PA-12) obtained in (3) above, the ratio of coarse particles having a particle size of 150μm or greater in water saturated state to swelling by the method mentioned above , the ratio of coarse particles having a particle size of 150μm or greater in the water-swollen state was very low 0.03 mass% for polymer microparticles (PA-11) and 0.10 mass% for polymer microparticles (PA-12), particle size he was homogeneous.

(5) A photograph from a digital microscope (420 times magnification) of a suspension (suspension in oil) of polymer microparticles (PA11) obtained in (1) above is depicted in FIG. 6, and a photograph from a digital microscope (420 times magnification) of polymer microparticles (PA-11) in a water-swollen state to swell obtained in (ii) from (4) above is shown in FIG. 7.

Examples 13 to 15 [Production of polymer microparticles (PA13) to (PA-15)] (1) Suspension of polymer microparticles (PA-13), suspension of polymer microparticles (PA-14) and suspension of polymer microparticles (PA-15) were produced according to the same procedures as in (1) to (5) Example 10, except that the type and amount of dispersion stabilizer used and the amount of polyethylene glycol diacrylate (Aronix M-243 manufactured by Toagosei Co., Ltd., average molecular weight 425) have been changed as shown in Table 6 below (all suspensions are suspensions of the slurry type in oil). The sorbitan monopalmitate (SP-10) used in Examples 13 to 15 has low solubility in n-heptane at low temperatures, in Examples 13 to 15, the polymerization reactor has been loaded with three types of dispersion stabilizers and n-heptane, the internal temperature in the polymerization reactor was set at 35 ° C, mixing was carried out for 1 hour to thereby produce a liquid in which the dispersion stabilizers were homogeneously dissolved (liquid dispersion stabilizer, oil phase). In each of Examples 13 to 15, a suspension of polymer microparticles can be produced as stably as in Example 10.

(2) (i) When a portion of each suspension of polymer microparticles from (PA-13) to (PA-15) obtained in (1) above was taken as a sample and tested at 420 times magnification using the same digital microscope as used in the Example 10, polymer microparticles (PA-13) were formed from a group of spherical polymer microparticles having a particle size distribution centralized around 20pm, polymer microparticles (PA-14) were formed from a group of spherical polymer microparticles having a particle size distribution centralized around 20pm, polymer microparticles ( PA-15) were formed from a group of spherical polymer microparticles having a particle size distribution centralized around 15pm, and aggregates (secondary particles),in which several polymer microparticles would be glued together, they were not observed in any of the polymer microparticles.

(ii) Moreover, when each dispersion of polymer microparticles from (PA-13) to (PA-15) was selected from the polymerization reactor, the adhesion of the polymer microparticles to the interior of the polymerization reactor was visually examined; in all cases, only a few polymer microparticles adhered to the liquid level inside the polymerization reactor, no adhesion to the walls of the polymerization reactor was observed.

(iii) When a portion of each of the suspensions of polymeric microparticles from (PA-13) to (PA-15) obtained in (1) above was taken as a sample and the amount of residue in the filter cake on a polyethylene filter (200 eyes, mesh 114μπ) was measured By the method mentioned above, a small amount of 0.019% by mass for polymer microparticles (PA-13), 0.014% by mass for polymer microparticles (PA-14) and 0.024% by mass for polymer microparticles (PA-15) remained, and the content of coarse particles was very small .

(3) The remainder of each suspension of polymer microparticles from (PA13) to (PA-15) obtained in (1) above was treated in the same manner as in (7) of Example 10, a polymer microparticle powder was obtained from (PA-13) to (PA-15).

(4) (i) When the average particle size (dry) and the water absorption rate of powdery polymer microparticles (PA-13) to (PA-15) obtained in (3) above were measured by the above methods, the average particle size of the polymer microparticles ( PA-13) was 20.7 μm and their water absorption ratio was 24.7 times, the average particle size of the polymer microparticles (PA-14) was 18.5 μm and their water absorption ratio was 19.0 times, the average polymer particle size the microparticles (PA-15) were 14.2 μm and their water absorption was 17.1 times.

(ii) The polymeric microparticle powder from (PA-13) to (PA-15) obtained in (3) above was loaded into a large volume of excess water after ion exchange and left at 25 ° C for 1 hour so that the particles could swell to a state saturation, this state was examined at 420 times magnification using the same digital microscope as used in Example 10, in each case the spherical shape of the particles was retained; polymer microparticles (PA-13) in water saturated state to swell had a particle size distribution centralized around 50pm, polymer microparticles (PA-14) in water saturated state to swell had a particle size distribution centralized around 40pm, and polymer microparticles (PA-15) when saturated with water for swelling, they had a particle size distribution centralized around 30pm.

(iii) The average particle size in water-swollen state for each powder of polymeric microparticles from (PA-13) to (PA-15) obtained in (3) above was measured by the method described above, was 44.5pm for polymer microparticles (PA -13), 38.1pm for polymer microparticles (PA14) and 33.1pm for polymer microparticles (PA-15).

(iv) For each powder of (PA-13) to (PA-15) polymer microparticles obtained in (3) above, when the ratio of coarse particles having a particle size of 150pm or greater in water-swollen state was determined by the method mentioned above , the ratio of coarse particles having a particle size of 150 μm or greater in a saturated water state to swell was very low and 0.00% by mass for polymer microparticles (PA-13), polymer microparticles (PA-14) and polymer microparticles (PA-14) 15), the particle size was uniform. Comparative Example 10 [Production of polymer microparticles (PB-10)]

The suspension of polymer microparticles (PB-10) was produced according to the same procedures as in (1) to (5) in Example 10, except that only 5.0 parts by mass of sorbitan monooleate (RHEODOL AO-10) was used as the dispersion stabilizer. by Kao Corporation, w / o emulsion emulsifier, HLB = 4.3), a large amount of aggregate aggregates was created at the start of the polymerization, the polymer microparticle suspension could not be produced.

Table 6

<td rowspan="2"></td><td colspan="6">Example</td><td>Example Comparative</td>

<td>10</td><td>11</td><td>12</td><td>13</td><td>14</td><td>15</td><td>10</td>

<td>Micro code</td><td>PA-</td><td>PA-</td><td>PA-</td><td>PA-</td><td>PA-</td><td>PA-</td><td></td>

<td>poly-particles</td><td>10</td><td>11</td><td>12</td><td>13</td><td>14</td><td>15</td><td>PB-10</td>

<td>mer</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>[Monophonic composition</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>meru (part</td><td>100</td><td>100</td><td>100</td><td>100</td><td>100</td><td>100</td><td>100.0</td>

<td>Mass)]</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td>0</td><td></td>

<td>Acrylic acid</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>diacrylate</td><td>14.8</td><td>14.8</td><td>14.8</td><td>10.6</td><td>13.6</td><td>17.7</td><td></td>

<td>polyethylene glycol</td><td>(2.5</td><td>(2.5</td><td>(2.5</td><td>(1.8</td><td>(2.3</td><td>(3.0</td><td>14.8</td>

<td>ethylene</td><td></td><td></td><td></td><td></td><td></td><td></td><td>(2.5)</td>

<td>(% molar%)</td><td>⁾</td><td>⁾</td><td>⁾</td><td>⁾</td><td>⁾</td><td>⁾</td><td></td>

<td>carried to acrylic acid)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>[Stabilizer dispersion] Stabilizer dispersion Type (1)¹)</td><td>M-1</td><td>M-6</td><td>M-7</td><td>M-1</td><td>M-1</td><td>M-1</td><td></td>

<td>The quantity used (bulk parts)</td><td>5.0</td><td>5.0</td><td>5.0</td><td>1.4</td><td>1.4</td><td>1.4</td><td></td>

<td>Stabilizer dispersion Type (2)¹⁾</td><td></td><td></td><td></td><td>AO10</td><td>AO10</td><td>AO10</td><td>AO-10</td>

<td>The quantity used (bulk parts)</td><td></td><td></td><td></td><td>2.0</td><td>2.0</td><td>2.0</td><td>5.0</td>

<td>Stabilizer dispersion Type (3)¹)</td><td></td><td></td><td></td><td>SPP10</td><td>SPP10</td><td>SPP10</td><td></td>

<td>The quantity used (bulk parts)</td><td></td><td></td><td></td><td>3.0</td><td>3.0</td><td>3.0</td><td></td>

<td>[Polymer microparticles] The degree of adhesion of polymer microparticles²)</td><td>AND</td><td>AND</td><td>AND</td><td>AND</td><td>AND</td><td>AND</td><td>_-3)</td>

<td>The amount of</td><td>0.06</td><td>0.01</td><td>0.01</td><td>0.01</td><td>0.01</td><td>0.02</td><td>_-3)</td>

<td>stability in the filter cake on polyethylene filter (% mass)</td><td>7</td><td>1</td><td>9</td><td>9</td><td>4</td><td>4</td><td></td>

<td>The mean particle size (Pm)</td><td>18.0</td><td>19.4</td><td>20.6</td><td>20.7</td><td>18.5</td><td>14.2</td><td>_-3)</td>

<td>The degree of water absorption (Times)</td><td>18.5</td><td>19.4</td><td>20.1</td><td>24.7</td><td>19.0</td><td>17.1</td><td>_-3)</td>

<td>The average particle size in the state of water saturation to swell (pm)</td><td>38.3</td><td>46.2</td><td>49.7</td><td>44.5</td><td>38.1</td><td>33.1</td><td>_-3)</td>

<td>The ratio of particles having a size of 150pm or bigger⁴⁾(% by weight)</td><td>0.07</td><td>0.03</td><td>0.10</td><td>0.00</td><td>0.00</td><td>0.00</td><td>_-3)</td>

1) Dispersion stabilizer:

ie Production 1 ie Production 6 and Production 7 produced

<td>M-1:</td><td>macromonomer</td><td>M-1</td>

<td>M-6:</td><td>macromonomer</td><td>M-6</td>

<td>M-7:</td><td>macromonomer</td><td>M-7</td>

AO-10: monooleate produced in Examplez produced in Examplez made in Example of sorbitan (RHEODOL AO-10 by Kao Corporation)

SP-P10: sorbitan monopalmitate (RHEODOL SP-P10 manufactured by Kao Corporation)

2) Degree of adhesion of polymer microparticles to the polymerization reactor

3) Large aggregates formed as the polymerization started, a suspension of polymer microparticles could not be obtained.

4) Ratio of particles having a size of 150μm or greater in a saturated state with water to swell.

As can be seen in the results of Examples 10 to 15 in Table 6 above, in Examples 10 to 15, in which hydrophilic (water-swellable) polymer microparticles are produced by suspension-phase suspension polymerization using a macromonomer having unsaturated radicalizable groups at vinyl-based monomer polymer terminations [especially, macromonomers (M1, M-6 and M-7)] as a dispersion stabilizer, hydrophilic microparticles of a crosslinked polymer having a suitable particle size of a few μm to several tenths of μη, with a homogeneous particle size can be obtained. particle size, having excellent water absorption capacity and capable of being well dispersed as individual primary particles without forming secondary particles by aggregation between particles in water,while maintaining a spherical shape when swollen by water absorption.

For comparison, as can be seen in the results of Comparative Example 10 in Table 6 above, in Comparative Example 10, wherein a macromonomer having unsaturated radicalizable groups on the vinyl-based monomer was used as a stabilizer for the suspension suspension polymerization. the vinyl polymer-derived monomer has been terminated, aggregation has occurred immediately after the polymerization started, and the phase inversion suspension polymerization can not be practiced.

Industrial application

In accordance with the process presented in the present invention, high-quality spherical polymer microparticles having a suitable particle size of several μm to several tenths of a pm, mainly 2 to 100 μm, with uniform particle size distribution can be produced with high productivity while maintaining high dispersion stability and polymerization stability, without causing aggregation of polymer particles, formation of clumps of these and adhesion of these to polymerization equipment, etc. during polymerization or after polymerization.

Polymer microparticles obtained in the process of the present invention, in particular hydrophilic cross-linkable polymer microparticles obtained by the process of the present invention are useful as cosmetic additives, basis for various chemical materials, filler, packing of chromatographic columns, light scattering agent, porosity enhancer, weight-reducing agent, agent against blocking and a measure to modify the surface of the recording paper.