Process for the preparation of latices using block copolymers as surfactants

[Technical field]

【0001】

The subject of the present invention is a process for producing latex using a block copolymer as a surfactant, and the latex composition produced by the process.

【0002】

The present invention also relates to the production of latex, which exhibits high resistance to water and can be used as a concrete or cement additive, especially in formulations intended for application in building materials, adhesives, paints or paper.

[Background technology]

【0003】

Latexes are products well known to those of skill in the art and at the same time are redispersible powders obtained from those latexes. Latex has a variety of applications, especially in paint or paper formulations (coating slips, bulk paper) or in construction applications (adhesives, pastes, smooth coatings, etc.). It is applied as an additive in. Latex imparts important properties to the formulation of the composition to which it is added, for example by its bondability, by its ability to form membranes, and by its ability to impart unique rheological properties.

【0004】

In general, in all applications of latex, the goal is to combine good colloidal stability in the aqueous formulation before drying with good resistance to water after drying.

【0005】

The process of making latex has been well known for many years. It is also known that a surfactant is added to the aqueous phase to suspend both the monomer and the polymer in small spheres suspended in water so that radical polymerization takes place inside the spheres. ing. However, the addition of this surfactant has the disadvantage that the surfactant may remain on the latex particles and be detrimental to the properties of the composition containing the latex.

[Disclosure of Invention]

[Problems to be Solved by the Invention]

【0006】

One of the objects of the present invention is to provide a latex production method that enables a solution to the above problems.

[Means for solving problems]

【0007】

This object and other objects are achieved by the present invention, i.e., the subject matter of the present invention is:-at least one ethylenically unsaturated monomer; -at least one radical polymerization initiator;-at least one hydrophilic block and at least one hydrophilic block. A process of producing latex by radical aqueous emulsion polymerization in the presence of at least one surface-active block copolymer; which comprises one hydrophobic block and is produced by a "living" production process using a transfer agent. The copolymers are:-the number average molecular weight is between 2 000 and 20 000, preferably between 4 000 and 16 000, and-the glass transition temperature of the hydrophobic block is lower than 30 ° C, preferably. Is lower than 25 ° C, higher than -100 ° C, -surface tension is concentration 10 in desalted water^-4Measured at mol / l under 20 ° C and 1 atmosphere, less than 60 millinewtons per meter (mN / m), preferably less than 50 mN / m-the transfer agent is for the radical polymerization. It has been inactivated.

【0008】

The present invention is also a formulation intended for application in the fields of building materials, paints, papers, adhesives and adhesives, the latex or latex produced by the process. Concers with formulations that wipe the redispersible powder obtained by drying.

【0009】

Similarly, the present invention relates to the use of latex and redispersible powders in formulations specifically intended for application in the field of construction or paints.

【0010】

However, other advantages and features of the present invention will also become apparent by reading the following description and examples.

[Best mode for carrying out the invention]

【0011】

According to the present invention, surface active block copolymers comprising at least one hydrophilic block and at least one hydrophobic block are produced by a "living" or "controlled" radical polymerization process, which is particularly described above. A transfer agent is used for the purpose of controlling radical polymerization. The hydrophilic block is preferably derived from a hydrophilic monomer, and the hydrophobic block is preferably derived from a hydrophobic monomer.

【0012】

Generally, said block copolymers can be obtained by any "living" or "controlled" polymerization process, eg:-xanthate according to the teachings of patent application WO 98/58974. Radical polymerization controlled by-Radical polymerization controlled by dithioester according to the teachings of patent application WO 98/01478,-Polymerization using nixide precursors according to the teachings of patent application WO 99/03894,-Patent application WO 99/31144 Radical Polymerization Controlled by Dithiocarbamate According to the Teachings of, -Atom Transfer Radical Polymerization (ATRP) According to the Teachings of Patent Application WO 96/30421,-Otu et al., Makromol. Chem. Rapid. Communi., 3,127 (1982) ), Radical polymerization controlled by an initiator,-Tatemoto et al., Jap. 50,127,991 (1975), Daikin Kogyo Co Ltd Japan, And Matyjaszewski et al., Macromolecules, 28,2093 (1995), Radical Polymerization Controlled by Degenerative Migration of Iodine,-HFmark, NmBikales, CGOverberger and g.menges, ed., "Encyclopedia of Polymer Science and Engineering" ", Vol.7, Wiley Interscience, New York, 1987, Webster OW," Group Transfer Polymerization ", group transfer polymerization according to the teachings of p.580-588, -controlled by tetraphenylethane derivatives Radical Polymerization (D. Braun et al., Macromol. Symp. 111, 63 (1996)),-Radical Polymerization Controlled by Organic Cobalt Complexes (Wayland et al., J. Am. Chem. Soc. 116, 7973 (1994)).

【0013】

Preferred transfer agents for carrying out a controlled polymerization process are selected from dithioesters, thioether-thiones, dithiocarbamates, and xanthates.

【0014】

A preferred polymerization is living radical polymerization with xanthate.

【0015】

The present invention further relates to a process for producing these block polymers. This process consists of the following steps: -at least one ethylenically unsaturated monomer, -at least one source of free radicals, -at least one transferant of formula (I), [0016].

[Chemical 1]<img file="JP2004530751A_D0001.tif" /> 【0017】

Steps to contact: · R is an R2O-, R2R'2N-, or R3-group: R2 and R'2 are the same or different, (i) alkyl, acyl, aryl, alkene, Or an alkyne group, or (ii) optionally an aromatic, saturated or unsaturated, carbonic ring, or (iii) a saturated or unsaturated heterocycle, these groups and rings (i), (ii). And (iii) may be substituted, R3 is an H, Cl, alkyl, aryl, alkene, or alkyne group, optionally substituted, saturated or unsaturated (hetero) cycle, alkylthio, alkoxycarbonyl, Represents an aryloxycarbonyl, carboxyl, acyloxy, carbamoyl, cyano, dialkyl- or diarylphosphonate, or dialkyl- or diarylphosphinate group, or polymer chain, where R1 is (i) optionally substituted alkyl, Acylic, aryl, alkene, or alkyne groups, or (ii) saturated or unsaturated carbonic rings, optionally substituted or aromatic, or (iii) optionally substituted, saturated or unsaturated, hetero. The contacting operation described above with a monomer representing a cycle or polymer chain, and 2-a different monomer from the preceding embodiment, and-a polymer obtained from the preceding embodiment instead of the precursor compound of chemical formula (I). It consists of a step of repeating at least once and a step of inactivating the transferant at the end of 3-polymerization .

【0018】

The R1, R2, R'2 and R3 groups are substituted phenyl or alkyl groups, substituted aromatic groups or the following groups: oxo, alkoxycarbonyl, or aryloxycarbonyl (-COOR), carboxyl (-COOH). , Acyloxy (-O₂CR), carbamoyl (-CONR)₂), Cyan (-CN), alkylcarbonyl, alkylarylcarbonyl, arylcarbonyl, arylalkylcarbonyl, isocyanate, phthalimide, maleimide, succinimide, amidino, guanidino, hydroxyl (-OH), amino (-NR)₂), Halogen, allyl, epoxy, alkoxy (-OR), S-alkyl, S-aryl or silyl, groups exhibiting hydrophilic or ionic properties, such as alkali salts of carboxylic acid and alkali salts of sulfonic acid, poly (alkylene · It may be substituted with an oxide) (PEO, PPO) chain, or a cation substituent (quaternary ammonium salt), where R represents an alkyl or aryl group.

【0019】

Preferably, the transfer agent of formula (I) is a dithiocarbonate selected from the compounds of formulas (IA), (IB) and (IC) below: [0020].

[Chemical 2]<img file="JP2004530751A_D0002.tif" /> 【0021】

Here: R2 and R'2 are (i) alkyl, acyl, aryl, alkene, or alkyne groups, or (ii) optionally aromatic, saturated or unsaturated, carbonic rings, or (iii) saturated. Or an unsaturated heterocycle, these groups and rings (i), (ii) and (iii) may be substituted, R1 and R1'are (i) optionally substituted alkyl , Acyl, aryl, alkene, or alkyne groups, or (ii) saturated or unsaturated, optionally substituted or aromatic carbonaceous rings, or (iii) optionally substituted, saturated or unsaturated. Represents a heterocycle or polymer chain of, · p is between 2 and 10.

【0022】

In stage 1, the first block of hydrophilic or hydrophobic polymer is synthesized depending on the nature and amount of the monomer used. In stage 2, other blocks of polymer are synthesized.

【0023】

Ethylene unsaturated monomers are selected in appropriate proportions to obtain surface active block copolymers from hydrophilic and hydrophobic monomers. This copolymer block exhibits the properties of the present invention. According to this process, if all subsequent polymerization is carried out in the same reactor, it is preferred to introduce new monomers after all the monomers commonly used in one stage have been consumed and initiate polymerization in the next stage. However, during the polymerization of the next block, it is possible that the hydrophilic or hydrophobic monomers of the preceding stage are still present. In such cases, these monomers are generally less than or equal to 5 mol% of all monomers, which in turn also participates in the polymerization, causing the introduction of hydrophilic or hydrophobic blocks into the next block.

【0024】

The surface-active block copolymer produced by this polymerization process is simply two blocks having a hydrophobic block and a hydrophilic block, or the hydrophilic block is surrounded by two hydrophobic blocks or a hydrophobic block. There can also be 3 blocks surrounded by 2 hydrophilic blocks.

【0025】

More specifically, this surface active block copolymer is obtained using at least one ethylenically unsaturated monomer selected from the following as the hydrophilic monomer: -unsaturated ethylenic mono- and dicarboxylic acids, eg. Acrylic acid, itaconic acid, maleic acid, or fumaric acid-a monoalkyl ester of the above types of dicarboxylic acids and preferably alkanols having 1 to 4 carbon atoms, and N-substituted derivatives thereof, such as 2- Hydroxyethyl acrylate or methacrylate, an amide of an unsaturated carboxylic acid, such as acrylamide or methacrylic acid, an ethylenic monomer containing a sulfonic acid group and an alkali metal or ammonium salt thereof, such as vinyl sulfonic acid, vinyl benzene sulfonic acid, alpha. -Acrylamide methylpropane sulfonic acid or 2-sulfoethyl methacrylate.

【0026】

However, the most preferred hydrophilic monomers are acrylic acid (AA), acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and styrene sulfonate (SS).

【0027】

Examples of hydrophobic monomers that can be used to make up hydrophilic blocks include, among others, (meth) acrylic acid esters, vinyl esters, and vinyl nitriles. The term "(meth) acrylic acid ester" refers to the hydrogenation or fluorination of acrylic acid and methacrylic acid C.₁-C₁₂Alcohol, preferably C₁-C₈Represents an ester with alcohol. Compounds of this type include: methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, t-butyl acrylate, methyl. Acrylate, ethyl methacrylate, n-butyl methacrylate, or isobutyl methacrylate. Preferred monomers are acrylic acid and linear or branched C₁-C₄Esters with alcohols such as methyl, ethyl, propyl and butyl acrylates.

【0028】

More specifically, vinyl nitriles include those having 3 to 12 carbon atoms, particularly acrylonitrile and methacrylonitrile. Other ethylenically unsaturated monomers that can be used alone or in admixture, or copolymerize with the monomers include:-vinyl carboxylic acid esters such as vinyl acetate, vinyl versate, propion. Vinyl acetate, -vinyl halide, -vinylamine amide, especially vinyl-formamide, or vinyl-acetamide, -unsaturated ethylenic monomer, complex containing secondary, tertiary or quaternary amino groups or nitrogen. Those comprising a cyclic group such as vinylpyridine, vinylimidazole, aminoalkyl (meth) acrylate and aminoalkyl (meth) acrylamide, such as dimethylaminoethyl acrylate or methacrylate, di-tert-butylaminoethyl acrylate or methacrylate, or Dimethylaminomethylacrylamide or-methacrylamide.

【0029】

As long as the composition of this block copolymer maintains its surface-active properties and the limits of number average molecular weight, glass transition temperature of hydrophobic groups, and surface tension are adhered to, the ratio of the proportions in the hydrophilic block is maintained. It is clear that it is possible to include hydrophobic monomers and to include a proportion of hydrophilic monomers in the hydrophobic block.

【0030】

Polymerization of copolymers can be carried out in aqueous and / or organic solvent media, eg, tetrahydrofuran, or linear, cyclic or branched C.₁-C₈It can be done with aliphatic alcohols such as methanol, ethanol, or cyclohexanol, or diols such as ethylene glycol. In particular, the hydrophilic monomers are acrylic acid (AA), acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and styrene sulfonate (SS), and the hydrophobic monomers are n-butyl acrylates. , Isobutyl acrylate, 2-ethylhexyl acrylate, or t-butyl acrylate, alcoholic solvents are particularly recommended.

【0031】

At the end of the controlled polymerization stage, the transferant located at one end of the chain of surfactant block polymer is inactivated by some suitable means for subsequent radical polymerization associated with the production of the original latex. .. It is possible that the properties of the polymerization reaction medium (eg, pH conditions, the properties of the components of the reaction medium, the monomers to be polymerized) can sufficiently inactivate the transferant by itself. It is recommended that the active chemical functional groups of the transferant be masked with a suitable chemical masking agent, or that the transferant be destroyed by hydrolysis, metal-catalyzed oxidation reaction or with primary radicals. If the transfer agent is Zantate, if necessary, the resulting copolymer is inactivated by heat treatment, eg, in the temperature range of 80-180 ° C, in the presence of alcohol amines, eg triethanolamine. It is recommended to do.

【0032】

Next, the ethylenically unsaturated monomer that can be used for producing latex will be described.

【0033】

Suitable monomers include those corresponding to the following chemical formulas: CXdX'd (= CVd-CV'd)_t= CH₂Where: -Xd and Xd'are the same or different, representing H, an alkyl group, or halogen, and -Vd and Vd' are the same or different, H, halogen, or R, OR, OCOR. , NHCOH, OH, NH₂, NHR, N (R)₂, (R)₂N⁺O^-, NHCOR, CO₂H, CO₂R, CN, CONH₂, CONHR, or CONR₂Representing a group, R is the same or different, selected from alkyl, aryl, aralkyl, alkaline, alkene, or organic silyl groups, optionally hyperfluorinated, and optionally carboxyl, epoxy, hydroxyl, alkoxy, amino, Substituted with one or more halogen or sulfone groups, -t has a value of 0 or 1.

【0034】

In certain embodiments of the invention, the monomer used is preferably a hydrophobic monomer. Examples of hydrophobic monomers include, in particular, styrene and its derivatives, butadiene, chloroprene, (meth) acrylic acid esters, vinyl esters and vinyl nitriles. The term "(meth) acrylic acid ester" refers to the hydrogenation or fluorination of acrylic acid and methacrylic acid C.₁-C₁₂Alcohol, preferably C₁-C₈Represents an ester with alcohol.

【0035】

More specifically, vinyl nitriles include those having 3 to 12 carbon atoms, particularly acrylonitrile and methacrylonitrile.

【0036】

It should be noted that styrene can be replaced, in whole or in part, with derivatives such as α-methylstyrene or vinyltoluene.

【0037】

Other ethylenically unsaturated monomers that can be used alone or in admixture, or copolymerize with the above monomers, include:-vinyl carboxylic acid esters,-vinyl halides, -vinylamines. Amides,-unsaturated ethylenically monomers containing a heterocyclic group containing a secondary, tertiary or quaternary amino group or nitrogen. Zwitterionic monomers such as sulfopropyl (dimethyl) aminopropyl acrylate can be used as well.

【0038】

Hydrophilic monomers such as-unsaturated ethylenic mono-and dicarboxylic acids-monoalkyl esters of the above types of dicarboxylic acids with alkanols, preferably having 1 to 4 carbon atoms, and N-substituted derivatives thereof. , -Amide of unsaturated carboxylic acid, -Ethenyl monomer containing sulfonic acid group and alkali metal or ammonium salt thereof, -Amid of unsaturated carboxylic acid, such as acrylamide, methacrylic amide, N-methylol acrylamide, N-methylol methacrylic amide. It should be noted that it is possible to use, or N-acrylamide, etc.

【0039】

It should be noted that all the monomers mentioned in relation to the definition of surface active block copolymers can be used for the production of latex. Therefore, you can refer to this part of the description.

【0040】

As the ethylenically unsaturated monomer, it is preferable to use at least one monomer selected from styrene or a derivative thereof, butadiene, chloroprene, (meth) acrylic acid ester, vinyl ester and vinylnitrile.

【0041】

The polymerization reaction according to the present invention is carried out in the presence of a radical polymerization initiator. The latter can be selected from the initiators conventionally used in radical polymerization. It may be, for example, one of the following initiators:-hydrogen peroxide, eg: tert-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyacetate, t-butyl peroxybenzoate. , T-butyl peroxyoctate, t-butyl peroxyneodecanoate, t-butyl peroxyisobutyrate, lowloyl peroxide, t-amyl peroxypivalate, t-butyl peroxypivalate, dicumyl Peroxide, benzoyl peroxide, potassium persulfate, or ammonium persulfate, -azo compound, eg: 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2-butanenitrile), 4 , 4'-azobis (4-pentanoic acid), 1,1'-azobis (cyclohexanecarbonitrile), 2- (t-butylazo) -2-cyanopropane, 2,2'-azobis [2-methyl-N- (1,1) -bis (hydroxymethyl) -2-hydroxyethyl] propionamide, 2,2'-azobis (2-methyl-N-hydroxyethyl) propionamide, 2,2'-azobis (N, N'-di Methyleneisobutyramidine) dichloride, 2,2'-azobis (2-aminopropane) dichloride, 2,2'-azobis (N, N'-dimethyleneisobutyramide), 2,2'- Azobis (2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide), 2,2'-azobis (2-methyl-N- [1,1-bis (hydroxymethyl)) Ethyl] propionamide), 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], or 2,2'-azobis (isobutyramide) dihydrate,-including the following combinations: Azobisisobuty system:

【0042】

The polymerization reaction is carried out as before, with alkoxylated mono-, di-, or trialkylphenols, alkoxylated mono-, di-, or tristyrylphenols, alkoxylated fatty alcohols and C.₈-C₁₂Alkali metal or ammonium salts of alkyl sulfates, fatty alcohols, alkoxylations and sulfated hemiesters, C₈-C₁₂A nonionic or anionic surfactant selected from alkyl sulphonate esters, etc. can be added to the polymerization medium.

【0043】

The polymerization temperature is, for example, between 50 and 120 ° C, and more particularly between 70 and 90 ° C.

【0044】

Thus, certain embodiments of the latex polymerization process according to the invention include the following stages: a) A stable aqueous pre-emulsion containing an ethylenically unsaturated monomer as a starting material and a surface-active block copolymer, eg, 1 Prepared with 2-3 parts by weight of monomer, b) A reaction mixture containing conventional surfactants, initiators and water as described above is introduced into the radical polymerization reactor and 1-10 A pre-emulsion prepared at stage a), preferably 3-7% by weight (mass)%, is added to the mixture, c) the reaction mixture obtained at the end of stage b) is a latex particle dispersed in water. The pre-emulsion obtained in stage a) is added, which is heated to a temperature between 40 and 90 ° C, preferably between 60 and 80 ° C, to give rise to the seeds that are formed. A latex is obtained from two separate inlets of the reactor with an amount of initiator, e) optionally, the latex obtained at Suzie d) is between 40 and 90 ° C, preferably 60 to 80. It is heated to a temperature of up to ° C.

【0045】

It is generally recommended to use an effective amount of block copolymer inside the polymerization medium to obtain the desired surfactant effect, but it is generally the total weight of the water used during the polymerization of the latex. On the other hand, it corresponds to the use of a surface-active block copolymer of 0.5 to 5, preferably 1 to 4% by weight (mass). In addition, it is recommended to use a copolymer in an amount of 1 to 8, preferably 2 to 5% by weight (mass), based on the total weight of the monomers used in the polymerization of the latex.

【0046】

Another subject of the present invention consists of a redispersible powder obtained by drying the latex produced by the process of the present invention. The latex can be dried in a manner known per se. That is, drying can be done at low temperature, or preferably by spraying. It can be done by any known device, such as a spray tower that combines spray spraying performed by a nozzle or turbine with a stream of hot gas. The inlet temperature of the hot gas (generally air) at the top of the column is preferably between 110 and 115 ° C, and the outlet temperature is preferably between 55 and 65 ° C. In one advantageous embodiment of the invention, drying is carried out in the presence of a drying additive. Ordinary dispersants can be used. For example, polyphenols, salts of glutamic acid, polyvinyl alcohol, polyvinylpyrrolidone, or cellulose derivatives can be mentioned. It should be noted that nonionic or anionic surfactants can also be used. In one particularly advantageous way, the amount of dry additive is less than 5% by weight (mass) of the polymer.

【0047】

Latex produced by the process of the present invention generally exhibits the following properties: Ca at concentrations in water greater than 0.25%:⁺⁺High resistance to ions, adjustable contact angle and surface tension, high stability to shear, high resistance to moisture after film formation, high thickening ability, and a tendency for almost no whitening.

【0048】

Latexes and redispersible powders, which are the subject of the present invention, can be used in conventional application fields, such as building materials, paints, paper, or adhesives including pressure sensitive adhesives.

【0049】

That is, the present invention is also the subject of a formulation comprising latex and redispersible powder produced by the process of the present invention, intended for application in the field of building materials.

【0050】

The present invention also relates to formulations containing this latex and redispersible powders intended for application in the field of paints.

【0051】

Finally, the present invention relates to formulations containing this latex and redispersible powders intended for application in the field of adhesives and pressure sensitive adhesives.

【0052】

Next, specific but non-limiting examples of the present invention will be described.

[Example]

【0053】

In the following examples: -Mn represents the number average molecular weight Mn of the polymer; Mn is represented by polystyrene equivalent (g / mol), -Mw represents the weight average molecular weight (g / mol), -Mw / Mn represents the polydispersity index. -Polymer is analyzed by chromatography (GPC) with THF as the elution solvent prior to hydrolysis. Example 1: <u style="single">Preparation of 50/50 p (BA) -bp (AA) (Poly (Butyl Acrylate) -Poly (Acrylic Acid)) Two Block Polymers by Weight with Zantate Type Reactive Ends</u>The following mixture: -3.04 g of zantate-A, S-ethylpropionyl O-ethyl dithiocarbonate (hereinafter referred to as zantate), -1.24 g of isopropanol, and -0.82 g of azobisisobutyronitrile ( AIBN), is introduced into a reactor containing 160 g of acetone, equipped with a magnetic stirrer and a reflux column.

【0054】

The mixture is then stirred and kept at 70 ° C. on reflux. 66 g acrylic acid (AA) and 15 g water are added slowly over 3 hours. Next, 0.41 g of azobisisobutyronitrile is added 1 hour after the addition, and an additional 0.41 g of azobisisobutyronitrile is added 2 hours after the first addition. After the addition of acrylic acid is completed, the polymerization is continued for another hour. An amount of 0.20 g of the reaction mixture is removed as a sample of PAA homopolymer.

【0055】

Then add 560 g of acetone to reduce the temperature to 65 ° C. 140 g of butyl acrylate (BA) is added slowly over 3 hours while maintaining the temperature at 65 ° C. At the beginning of the addition of BA, 0.40 g of AIBN is added. The reaction is continued for an additional 3 hours. The reaction mixture is left to cool and the solvent is almost completely removed by a rotor vapor (rotary evaporator). The obtained residue is dispersed in water and lyophilized. Polymers are analyzed by carbon-13 nuclear magnetic resonance and by measuring acid content. The number average molecular weight of this copolymer is 15,000. The glass transition temperature of the hydrophobic block is -54 ° C. Surface tension is 10^-4It is 55 mN / m at mol / l. Example 2: <u style="single">Preparation of 70/30 p (BA) -bp (AA) (Poly (Butyl Acrylate) -Poly (Acrylic Acid)) Two Block Polymers by Weight with Zantate Type Reactive Ends</u>The following mixture: -0.61 g of zantate-A, S-ethylpropionyl O-ethyl dithiocarbonate (hereinafter referred to as zantate), -4.25 g of isopropanol, and -0.16 g of azobisisobutyronitrile (hereinafter referred to as zantate). AIBN), is introduced into a reactor containing 160 g of acetone, equipped with a magnetic stirrer and a reflux column under a nitrogen atmosphere.

【0056】

The mixture is then stirred and kept at 70 ° C. on reflux. 13.2 g of acrylic acid (AA) and 30.3 g of water are added slowly over 3 hours. Next, 0.08 g of azobisisobutyronitrile is added 1 hour after the addition, and an additional 0.08 g of azobisisobutyronitrile is added 2 hours after the first addition. After the addition of acrylic acid is completed, the polymerization is continued for another hour. An amount of 4.1 g of the reaction mixture is removed as a sample of PAA homopolymer.

【0057】

Then add 112 g of acetone to reduce the temperature to 65 ° C. 28 g of butyl acrylate (BA) is added slowly over 3 hours while maintaining the temperature at 65 ° C. At the beginning of the addition of BA, 0.08 g of AIBN is added. The nitrogen purge is stopped and the reaction continues for an additional 12 hours. The reaction mixture is left to cool and the solvent is almost completely removed by a rotor vapor (rotary evaporator). The obtained residue is dispersed in water and lyophilized. Polymers are analyzed by carbon-13 nuclear magnetic resonance and by measuring acid content. The number average molecular weight of this copolymer is 15,000. The glass transition temperature of the hydrophobic block is -54 ° C. Surface tension is 10^-4It is 52 mN / m at mol / l. Example 3: <u style="single">Preparation of 60/40 p (BA) -bp (AA) (Poly (Butyl Acrylate) -Poly (Acrylic Acid)) Two Block Polymers by Weight with Zantate Type Reactive Ends</u>The following mixture: -1.53 g of zantate-A, S-ethylpropionyl O-ethyl dithiocarbonate (hereinafter referred to as zantate), -10.72 g of isopropanol, and -0.42 g of azobisisobutyronitrile ( AIBN), is introduced into a reactor containing 160 g of acetone, equipped with a magnetic stirrer and a reflux column.

【0058】

The mixture is then stirred and kept at 70 ° C. on reflux. 44.0 g acrylic acid (AA) and 75.4 g water are added slowly over 3 hours. Next, 0.21 g of azobisisobutyronitrile is added 1 hour after the addition, and an additional 0.21 g of azobisisobutyronitrile is added 2 hours after the first addition. After the addition of acrylic acid is completed, the polymerization is continued for another hour. An amount of 10.98 g of the reaction mixture is removed as a sample of PAA homopolymer.

【0059】

Then add 280 g of acetone to reduce the temperature to 65 ° C. 60 g of butyl acrylate (BA) is added slowly over 3 hours while maintaining the temperature at 65 ° C. At the beginning of the addition of BA, 0.20 g of AIBN is added. The nitrogen purge is stopped and the reaction continues for an additional 12 hours. The reaction mixture is left to cool and the solvent is almost completely removed by the rotor vapor (rotary evaporator). The obtained residue is dispersed in water and lyophilized. Polymers are analyzed by carbon-13 nuclear magnetic resonance and by measuring acid content. The number average molecular weight of this copolymer is 15,000. The glass transition temperature is -54 ° C for the PBA hydrophobic block and 105 ° C for the PAA block. Surface tension is 10^-4It is 58.8 mN / m at mol / l. Example 4: <u style="single">Preparation of 80/20 p (BA) -bp (AA) (Poly (Butyl Acrylate) -Poly (Acrylic Acid)) Two Block Polymers by Weight with Zantate Type Reactive Ends</u>The following mixture: -0.61 g of zantate-A, S-ethylpropionyl O-ethyl dithiocarbonate (hereinafter referred to as zantate), -4.21 g of isopropanol, and -0.16 g of azobisisobutyronitrile (hereinafter referred to as zantate). AIBN), is introduced into a reactor containing 160 g of acetone, equipped with a magnetic stirrer and a reflux column.

【0060】

The mixture is then stirred and kept at 70 ° C. on reflux. 8.80 g acrylic acid (AA) and 30.35 g water are added slowly over 3 hours. Next, 0.08 g of azobisisobutyronitrile is added 1 hour after the addition, and an additional 0.08 g of azobisisobutyronitrile is added 2 hours after the first addition. After the addition of acrylic acid is completed, the polymerization is continued for another hour. An amount of 3.7 g of the reaction mixture is removed as a sample of PAA homopolymer.

【0061】

Then add 112 g of acetone to reduce the temperature to 65 ° C. 32 g of butyl acrylate (BA) is added slowly over 3 hours while maintaining the temperature at 65 ° C. At the beginning of the addition of BA, 0.08 g of AIBN is added. The nitrogen purge is stopped and the reaction continues for an additional 12 hours. The reaction mixture is left to cool and the solvent is almost completely removed by a rotor vapor (rotary evaporator). The obtained residue is dispersed in water and lyophilized. Polymers are analyzed by carbon-13 nuclear magnetic resonance and by measuring acid content. The number average molecular weight is 15 000. The glass transition temperature is -54 ° C for the PBA hydrophobic block and 105 ° C for the PAA block. Example 5: <u style="single">Preparation of 55/45 p (BA) -bp (AA) (Poly (Butyl Acrylate) -Poly (Acrylic Acid)) Two Block Polymers by Weight with Zantate Type Reactive Ends</u>The following mixture: -0.61 g of zantate-A, S-ethylpropionyl O-ethyl dithiocarbonate (hereinafter referred to as zantate), -4.31 g of isopropanol, and -0.17 g of azobisisobutyronitrile ( AIBN), is introduced into a reactor containing 160 g of acetone, equipped with a magnetic stirrer and a reflux column.

【0062】

The mixture is then stirred and kept at 70 ° C. on reflux. 19.80 g of acrylic acid (AA) and 30.31 g of water are added slowly over 3 hours. Next, 0.08 g of azobisisobutyronitrile is added 1 hour after the addition, and an additional 0.08 g of azobisisobutyronitrile is added 2 hours after the first addition. After the addition of acrylic acid is completed, the polymerization is continued for another hour. An amount of 4.76 g of the reaction mixture is removed as a sample of PAA homopolymer.

【0063】

Then add 112 g of acetone to reduce the temperature to 65 ° C. 22 g of butyl acrylate (BA) is added slowly over 3 hours while maintaining the temperature at 65 ° C. At the beginning of the addition of BA, 0.08 g of AIBN is added. The nitrogen purge is stopped and the reaction continues for an additional 12 hours. The reaction mixture is left to cool and the solvent is almost completely removed by a rotor vapor (rotary evaporator). The obtained residue is dispersed in water and lyophilized. Polymers are analyzed by carbon-13 nuclear magnetic resonance and by measuring acid content. The number average molecular weight is 15 000. The glass transition temperature is -54 ° C for the p (BA) hydrophobic block and 105 ° C for the p (AA) block. Surface tension is 10^-4It is 52.0 mN / m at mol / l. Example 6: <u style="single">Xanthate-type reactive ends by weight p (BA) / p (AM) ratio: 60 / 40p (BA)</u>_{<u style="single">3000</u>}<u style="single">-bp (AM)</u>_{<u style="single">2000</u>}<u style="single">Preparation of two-block polymer (poly (butyl acrylate) -polyacrylamide)</u><u style="single">1) Stage 1: p (BA)</u>_{<u style="single">3000</u>}<u style="single">-X (X = xanthate) monoblock composition</u>Composition of reaction mixture:<img file="JP2004530751A_D0003.tif" />The above components are charged into a 250 ml polymerization reactor equipped with a magnetic stirrer. The reaction is carried out in a dry nitrogen atmosphere for 20 minutes, after which the reaction mixture is heated to 60 ° C and maintained at this temperature for 20 hours. A small amount of polymer sample is taken from time to time to monitor conversion. The content of solid matter is 28.09%.<u style="single">2) Stage 2: p (BA)</u>_{<u style="single">3000</u>}<u style="single">-bp (AM)</u>_{<u style="single">2000</u>}<u style="single">-X Two-block composition</u>Composition of reaction mixture:<img file="JP2004530751A_D0004.tif" />The above ingredients are loaded into a drying vessel for 20 minutes under a dry nitrogen atmosphere and then transferred to a polymerization reactor with a syringe having two nozzles. At the end of the transfer, the reaction mixture is heated to 60 ° C and kept at this temperature for 20 hours. A small amount of polymer sample is taken from time to time to monitor conversion. The content of solid matter is 24.59%. The reaction mixture is naturally cooled and the solvent is almost completely removed using a rotor vapor (rotary evaporator). The number average molecular weight is 5,000. The glass transition temperature is -54 ° C for the PBA hydrophobic block and 165 ° C for the PAM block. The surface tension is 58 mN / m. Example 7: <u style="single">P (BA) / p (AM) weight ratio with xanthate-type reactive ends in ethanol: 80 / 20p (BA)</u>_{<u style="single">4000</u>}<u style="single">-bp (AA)</u>_{<u style="single">1000</u>}<u style="single">Preparation of two-block polymer (poly (butyl acrylate) -poly (acrylic acid))</u><u style="single">1) Stage 1: p (BA)</u>_{<u style="single">4000</u>}<u style="single">-X (X = xanthate) monoblock composition</u>Composition of reaction mixture:<img file="JP2004530751A_D0005.tif" />The above components are charged into a 250 ml polymerization reactor equipped with a magnetic stirrer. The reaction is carried out in a dry nitrogen atmosphere for 20 minutes, after which the reaction mixture is heated to 60 ° C and maintained at this temperature for 20 hours. A small amount of polymer sample is taken from time to time to monitor conversion. The content of solid matter is 30.04%.<u style="single">2) Stage 2: p (BA)</u>_{4<u style="single">000</u>}<u style="single">-bp (AM)</u>_{1<u style="single">000</u>}<u style="single">-X two blocks</u>Composition of synthetic reaction mixture:<img file="JP2004530751A_D0006.tif" />The above ingredients are loaded into a drying vessel for 20 minutes under a dry nitrogen atmosphere and then transferred to a polymerization reactor with a syringe having two nozzles. At the end of the transfer, the reaction mixture is heated to 60 ° C and kept at this temperature for 20 hours. A small amount of polymer sample is taken from time to time to monitor conversion. The content of solid matter is 30%. The reaction mixture is naturally cooled and the solvent is almost completely removed using a rotor vapor (rotary evaporator). The number average molecular weight of the copolymer is 5,000. The glass transition temperature is -54 ° C for the PBA hydrophobic block and 105 ° C for the PAA block. Example 8: <u style="single">p (BA)</u>_{<u style="single">7500</u>}<u style="single">-bp (AA)</u>_{<u style="single">7500</u>}<u style="single">Synthesis of two blocks with -X and p (BA) / p (AA) weight ratio (50/50)</u><u style="single">A) Stage 1: p (BA)</u>_{<u style="single">7500</u>}<u style="single">-X Monoblock composition</u>Composition of reaction mixture:<img file="JP2004530751A_D0007.tif" />The above components are charged into a 250 ml polymerization reactor equipped with a magnetic stirrer. The reaction is carried out in a dry nitrogen atmosphere for 20 minutes, after which the reaction mixture is heated to 60 ° C and maintained at this temperature for 20 hours. A small amount of polymer sample is taken from time to time to monitor conversion. The content of solid matter is 30.2%.<u style="single">2) Stage 2: p (BA)</u>_{<u style="single">7500</u>}<u style="single">-bp (AA)</u>_{<u style="single">7500</u>}<u style="single">-X Two-block composition</u>Composition of reaction mixture:<img file="JP2004530751A_D0008.tif" />The above ingredients are loaded into a drying vessel for 20 minutes under a dry nitrogen atmosphere and then transferred to a polymerization reactor with a syringe having two nozzles. At the end of the transfer, the reaction mixture is heated to 60 ° C and kept at this temperature for 20 hours. A small amount of polymer sample is taken from time to time to monitor conversion. The content of solid matter is 30%. The reaction mixture is naturally cooled and the solvent is almost completely removed using a rotor vapor (rotary evaporator). The number average molecular weight of the copolymer is 15,000. The glass transition temperature is -54 ° C for the p (BA) hydrophobic block and 105 ° C for the p (AA) block. The surface tension is 55 mN / m. Example 9: <u style="single">p (BA)</u>_{<u style="single">1000</u>}<u style="single">-bp (AA)</u>_{<u style="single">4000</u>}<u style="single">Synthesis of two blocks with -X and p (BA) / p (AA) weight ratio (20/80)</u><u style="single">A) Stage 1: p (BA)</u>_{<u style="single">1000</u>}<u style="single">-X Monoblock composition</u>The procedure of stage A) of Example 8 is repeated exactly, but the reaction mixture:<img file="JP2004530751A_D0009.tif" />Is used.

【0064】

The content of solid matter is 30.2%.<u style="single">2) Stage 2: p (BA)</u>_{<u style="single">1000</u>}<u style="single">-bp (AA)</u>_{<u style="single">4000</u>}<u style="single">-X Two-block composition</u>The procedure of stage B) of Example 8 is repeated exactly, but the reaction mixture:<img file="JP2004530751A_D0010.tif" />Is used.

【0065】

The reaction mixture is naturally cooled and the solvent is almost completely removed using a rotor vapor (rotary evaporator). The number average molecular weight of the copolymer is 5,000. The glass transition temperature is -54 ° C for the PBA hydrophobic block and 105 ° C for the PAA block. The surface tension is 45.11 mN / m. Example 10:<u style="single">p (BA)</u>_{<u style="single">2000</u>}<u style="single">-bp (AM)</u>_{<u style="single">3000</u>}<u style="single">Synthesis of two blocks with -X and p (BA) / p (AM) weight ratio (40/60)</u><u style="single">A) Stage 1: p (BA)</u>_{<u style="single">1000</u>}<u style="single">-X Monoblock composition</u>The procedure of stage A) of Example 8 is repeated exactly, but the reaction mixture:<img file="JP2004530751A_D0011.tif" />Is used.

【0066】

The content of solid matter is 37.4%.<u style="single">2) Stage 2: p (BA)</u>_{<u style="single">2000</u>}<u style="single">-bp (AM)</u>_{<u style="single">3000</u>}<u style="single">-X Two-block composition</u>The procedure of stage B) of Example 8 is repeated exactly, but the reaction mixture:<img file="JP2004530751A_D0012.tif" />Is used.

【0067】

The reaction mixture is naturally cooled and the solvent is almost completely removed using a rotor vapor (rotary evaporator). The number average molecular weight of the copolymer is 5,000. The glass transition temperature is -54 ° C in the p (BA) hydrophobic block and 165 ° C in the p (AM) block. The surface tension is 52 mN / m. Example 11: <u style="single">Stage of degradation of thiocarbonylthio (dithiocarbonate) at the end of the copolymer chain</u>The decomposition stage is common and applies to all copolymers from Examples 1 to 10: 6 g coweight obtained in any of Examples 1 to 10 in a sealed container equipped with a magnetic stirrer. 0.09 g of triethanolamine is added to the 30 wt (mass)% solution in the copolymerized tetrahydrofuran. Shake the container to stir and heat in an oil bath at 160 ° C for 16 hours. The properties of the inactivated polymer are¹³Measured by C NMR. The ratio of C = S groups at 216 ppm to C = O groups in the polymer at 176 ppm decreases as a function of time. At the end of the reaction, the C = S group disappears. Example 12: Production of Latex Containing Block Copolymer Prepared in Example 6 of the above Latex Production Process: 81 g of deionized water, 5.20 g of MMA (methyl methacrylate), 4.7 g of butyl acrylate (BA) ) And 1.00 g of methacrylic acid are introduced into a container equipped with a magnetic stirrer and a reflux column.

【0068】

The mixture is heated to 80 ° C with stirring and purged with nitrogen.

【0069】

In addition, a pre-emulsion of the monomer is prepared as follows: 116 g deionized water, 5.20 g MMA (methyl methacrylate), 4.7 g butyl acrylate (BA), 1.00 g methacrylic acid, and 0.2 g. The block copolymer prepared in Example 6 above is mixed.

【0070】

10 g of the above pre-emulsion is rapidly added to the mixture heated to 80 ° C, followed by 228.2 g / mol ammonium persulfate and 342.3 g / mol Na.₂CO₃A solution of 25% by weight (mass) of the initiator containing the initiator is charged into the reactor for 3 hours and the temperature is maintained at 80 ° C. throughout the process of adding the reactants. Once this addition is complete, the reaction mixture is kept at 85 ° C for 30 minutes. It is then cooled to 30 ° C, filtered through a 100 mesh sieve and pH adjusted with 28% aqueous ammonium solution.

【0071】

The final latex exhibits the following properties: solid content 44.78%; agglomerates 0.12%; latex particle size 134.7 nm; Ca at concentrations in water higher than 0.25%⁺⁺High resistance to ions; Water contact angle of latex film is 76.5 °; Stable at pH 6.27 with shear of 2 minutes and 30 seconds; No whitening is observed; Minimum film formation temperature: 12 ° C. Example 13: Production of latex containing the block copolymer prepared in Example 10 above: The procedure of Example 12 above is exactly repeated, but the block copolymer used is that prepared in Example 3. Is.

【0072】

The final latex exhibits the following properties: solid content 45.00%; agglomerates 0.30%; latex particle size 108.3 nm; Ca at concentrations in water higher than 0.25%⁺⁺High resistance to ions; Water contact angle of latex film is 66.9 °; Stable at pH 9.03 with shear of 4 minutes and 40 seconds; Whitening: observed (slight); Minimum film formation temperature: 12 ° C. Comparative Example 14: Latex production without block copolymer The procedure of Example 12 above is exactly repeated, but no block copolymer is used.

【0073】

The final latex exhibits the following properties: solid content 45.00%; agglomerates 0.12%; latex particle size 127.0 nm; Ca at concentrations in water higher than 0.25%⁺⁺High resistance to ions; Water contact angle of latex film is 62 °; Stable at pH 8.99 with shear of 5 minutes and 10 seconds; Whitening: Clearly observed; Minimum film formation temperature: 12 ° C.

【0074】

It is clear that the properties of the resulting latex are inferior, especially with respect to whitening and resistance to Ca ++ ions.