Process to disperse organic microparticles / nanoparticles into non-aqueous resin medium

[0001] In the coating industry, it is known to produce organic microparticles / nanoparticles to give unique coating properties. These organic microparticles / nanoparticles are produced by emulsion polymerization in an aqueous medium or by dispersion polymerization in a non-aqueous medium. Techniques for producing these organic microparticles / nanoparticles are very well documented. These key techniques are introduced into the process of ensuring microparticle / nanoparticle stability during the polymerization process and functionality of the microparticles / nanoparticles for later use.

[0002] German Patent DE 2746481 describes a procedure for the production of reactive microgels from unsaturated polyesters and reactive monomer. The unsaturated polyester was emulsified in water with / without any optional surfactant under constant stirring. Reactive microgels had a diameter of 10 to 300 nanometers and had reactive hydroxyl or carboxyl groups on the surface. The weight ratio of unsaturated polyester to monomer was from 1:10 to 10: 1 in the production of reacting microgels.

[0003] US Patent No. 5,176,959 describes cross-linked polymer microparticles prepared by emulsion polymerization of a monomer mixture comprising a cross-linking monomer having multiple polymerization sites in the molecule in an aqueous medium containing a polymeric amide-acid and a neutralizing base as an emulsifying / dispersing agent. Polymer microparticles were incorporated into the thermosetting coating composition for rheology control and other purposes.

[0004] US Patent No. 5,565,504 describes an aqueous dispersion of a reacting microgel containing a polymer having at least one polyester containing an allyl ether or a urethane bonded polyester. The microgels had an average diameter of 10 to 1000 nanometers. The microgels were insoluble, but swelled in commonly used organic solvents. The dispersion dries without an additional film-forming agent to form a uniform, transparent and responsive film.

[0005] A coating composition containing crosslinked microparticles is also described in US Patent No. 2005/0228124. Cross-linked microparticles were prepared from (i) a C8 to C20 ester of (meth) acrylic acid; (ii) a polymerizing ethylenically unsaturated monomer having a polar functional group; and (iii) optionally, a polymerizable ethylenically unsaturated monomer in which (i), (ii) and (iii) are different from each other; and the polymer had a glass transition temperature of no more than -10 ° C.

[0006] US Patent No. 7,091,275 describes an aqueous polymer composition comprising selected polymer nanoparticles. The polymer nanoparticles contained, as polymerized units, at least one polyethylene unsaturated monomer and at least one water soluble monomer. Polymer nanoparticles had an average diameter in the range of 1 to 50 nanometers. The aqueous polymer composition is useful for producing coatings with at least one improved property compared to a coating in which selected polymer nanoparticles are not used.

[0007] US Patent No. 6,586,097 describes cross-linked microparticles between 10-300 nanometers in size. Cross-linked microparticles were obtained by dispersion polymerization in a non-aqueous medium which was a non-solvent compound for the polymer formed. The reaction composition included: at least one monomer A, containing only one unsaturated ethylene bond, which imparted self-stabilization of microparticles during and after polymerization, without the addition of any stabilizing agent; at least one compound B having at least two unsaturated ethylene bonds; and optionally, at least one compound C having only one unsaturated ethylene bond and / or at least one compound D which is different from A, B and C and has at least one unsaturated ethylene bond which is subject to a polymerization-mediated radical and at least one other a reactive functional group f1 that is different from an unsaturated ethylene bond.

[0008] US Patent No. 6,878,776 describes thermosetting compositions, comprising cross-linked polymer microparticles having a size in the range from 10 to 300 nm and having at least one reactive functional group that can react with at least one of the reactive components of the thermosetting composition. These microparticles may also contain at least one second reactive functional group that can react with another functional group of the same type present on another microparticle and / or in the reactant component of the thermosetting composition. These microparticles are at least partially soluble, miscible and / or dispersible in the initial thermosetting composition.

[0009] WO 2008/006580 describes a method of producing organic nanoparticles in steps (a) of preparing a solution containing an unsaturated polyester and / or a vinyl ester resin, an initiator and a hydrophobic monomer; (b) emulsifying the solution obtained in step (a) in an aqueous phase; and then (c) curing the emulsified solution. European Patent No. EP 1,484,355 describes a method for producing polymer nanoparticles with an average particle diameter of 1 to 200 nanometers. This process does not have an emulsion and results in a high level of polymer nanoparticles equal to or greater than 30% by weight.

[0010] Nano-scale substances such as carbon black, colloidal silica, titanium dioxide and organo-clay have been made and used for decades. In order to completely disperse these substances at the nano scale in the resin environment, usually high shear mechanical mixing or chemical delamination is used during the dispersion process. US Patent No. 6,887,931 describes thermosetting inorganic clays containing inorganic clays treated in situ with an intercalating agent and an intercalating agent. Publication No. CN 1454931 describes a method for incorporating silicon dioxide into an unsaturated polyester resin. Silicon dioxide was added to the reactor at the beginning or during the polycondensation reaction in the production of unsaturated polyester resin. Silicon dioxide may be in the form of a powder, colloidal aqueous solution, organic solution or gel.

[0011] The object of the present invention is to provide an alternative low-cost method of dispersing organic microparticles / nanoparticles in a resin environment, especially in a resin environment containing a solvent incompatible with the dispersion of organic nanoparticles. Organic microparticles / nanoparticles can be produced by emulsion polymerization, solution polymerization or dispersion polymerization. Organic microparticles / nanoparticles have an average particle diameter of 10 to 1000 nanometers, preferably 20 to 500 nm. Organic microparticles / nanoparticles are incorporated into the non-aqueous resin medium during synthesis of the resin medium. Organic microparticles / nanoparticles can be added at various stages in the synthesis of the resin environment. Various resin systems can be used to produce organic microparticles / nanoparticles; therefore, the properties of the organic microparticles / nanoparticles can be designed in such a way that they exhibit the desired performance characteristics for end uses of the resin environment.

[0012] The present invention relates to a method of dispersing organic microparticles / nanoparticles in a non-aqueous resin medium. The method comprises the steps of: a) preparing a first resin dispersion / emulsion in water or a solvent or mixture, said resin having an unsaturated bond in the polymer chain and optionally containing at least one ethylenically unsaturated monomer; b) curing this resin dispersion by adding a monomer and an initiator or initiator; c) the cured dispersion / emulsion is added during the steps of synthesizing the second resin medium.

[0013] The resin system used to prepare the dispersion / emulsion may be unsaturated polyester, vinyl ester, polyurethane, unsaturated hybrid polyester / urethane, crosslinkable acrylics like multifunctional (meth) acrylic monomers and / or oligomers, melamine or a mixture of any of these feed. The dispersion / emulsion medium is usually water, but it may contain small amounts of water miscible organic solvent. In some cases, water can be completely replaced with an organic solvent, and the organic solvent can also be used as a raw material in the synthesis of a second (final) resin medium. The resin dispersion / emulsion may additionally contain one or more surfactants.

[0014] This first resin dispersion / emulsion is cured by adding a monomer and an initiator or initiator. Hardened organic microparticles / nanoparticles are freely suspended in water and / or an organic solvent. The suspension of organic microparticles / nanoparticles in water and / or an organic solvent can be added to the non-aqueous medium of the second resin at various stages during the resin synthesis process. Water and / or organic solvent is removed from the suspension of organic microparticles / nanoparticles of the non-aqueous medium of the second resin at the same time as the water is removed from the non-aqueous resin environment. When an organic solvent is also used in the synthesis of the resin medium, it is not removed and reacted with other components to create a resin medium. The amount of organic nanoparticles in the resin medium may be 2 to 30%, preferably 2 to 20% by weight based on the final resin product in the monomer.

[0015] Organic microparticles / nanoparticles are usually produced by the liquid phase method.

The most commonly used liquid phase methods for producing organic microparticles / nanoparticles are emulsion polymerization in an aqueous environment or dispersion polymerization in a non-aqueous environment. Techniques for producing these organic microparticles are very well documented. These organic microparticles / nanoparticles are not crosslinked or are slightly crosslinked and swell in the solvent. These organic microparticles / nanoparticles are mainly used for coating. Organic microparticles / nanoparticles can be added to the coating formulation directly when the solvents of both systems are compatible.

[0016] The organic microparticles / nanoparticles can be made into a powder using various drying techniques. However, organic microparticles / nanoparticles tend to agglomerate during the drying process and the dry powder particle size is usually larger than the original particle size in solution. To obtain organic microparticles / nanoparticles with a particle size smaller than 1000 nanometers, the microparticle / nanoparticle suspension should be diluted thoroughly before drying. In this case, the cost of energy will be very high. It is almost impossible to obtain microparticles / nanoparticles in powder form with the same particle size as in the suspension.

[0017] The dispersion of dry inorganic microparticles / nanoparticles in a resin environment presents another challenge. In order to fully disperse microparticles / nanoparticles in a resin environment, high shear mechanical mixing or chemical delamination is usually used during the dispersion process.

[0018] The object of the present invention is to provide a low-cost alternative method of dispersing organic microparticles / nanoparticles in a non-aqueous resin medium, especially in a resin medium containing an incompatible solvent relative to the dispersion of organic nanoparticles. Organic microparticles / nanoparticles can be produced by emulsion polymerization, solution polymerization or dispersion polymerization. Organic microparticles / nanoparticles have an average particle diameter of 10 to 1000 nanometers. Organic microparticles / nanoparticles are incorporated into the non-aqueous resin medium during synthesis of the resin medium. Organic microparticles / nanoparticles can be added at various stages in the synthesis of the resin environment. Various resin systems can be used to produce organic microparticles / nanoparticles; therefore, the properties of the organic microparticles / nanoparticles can be designed in such a way that they exhibit the desired performance characteristics for end uses of the resin environment.

[0019] The invention relates to a method of dispersing organic microparticles / nanoparticles in a non-aqueous resin medium. The method includes stages in which:

(a) A dispersion / emulsion of the first resin is prepared in water or solvent, the resin having an unsaturated bond in the polymer chain and optionally containing a monomer.

(b) The resin dispersion is cured by adding monomer and initiator or initiator (alone) to form these microparticles / nanoparticles.

(c) A cured dispersion / emulsion is added during the steps for synthesizing this non-aqueous medium of the second resin.

[0020] The resin system used to prepare the resin dispersion / emulsion may be an unsaturated polyester, a vinyl ester, a polyurethane containing an unsaturated bond, an unsaturated hybrid polyester / urethane, crosslinkable acrylics (crosslinked acrylated monomers / oligomers) or a mixture of any of these resins. The resin dispersion / emulsion is usually water based, but it may contain a small amount of water miscible organic solvent. In some cases, water can be completely replaced with an organic solvent, and the organic solvent can also be used as a raw material in the synthesis of the resin environment. The resin dispersion / emulsion may additionally contain a surfactant. The resin system may contain other additives, such as inhibitors and stabilizing agents, traditionally used in such resin systems.

[0021] The unsaturated polyester resin has at least one alkene dicarboxylic moiety and is preferably an oligomer of compound α, e-ethylenically unsaturated dicarboxylic acid obtained by condensation reaction of one or more saturated di- or polycarboxylic acids or anhydride and unsaturated di- or polycarboxylic acid or anhydride with glycol or polyhydric alcohol. The unsaturated polyester resin can also be prepared from unsaturated di- or polycarboxylic acid (s) or anhydride (s) with glycols and / or polyhydric alcohol (s). Examples of suitable saturated di- or polycarboxylic acids include isophthalic, orthophthalic, terephthalic, adipic, succinic, sebacic acid, trigemitic anhydride, and mixtures of two or more of these compounds, with isophthalic acid being preferred. Typical unsaturated carboxylic acids or anhydrides include maleic acid, fumaric acid, citraconic acid, chloromaleic acid, allyl succinic acid, itaconic acid, mesaconic acid, their anhydrides and mixtures of two or more of these compounds, preferably maleic anhydride. Examples of polyhydric alcohols that are useful for the invention include neopentyl glycol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, polyethylene glycols, glycerol, mannitol, 1,2-propanediol, pentaerythritol, 1 , 6-hexanediol, 1,3-butylene glycol and mixtures of two or more of such compounds. The preparation of such resins is known to those skilled in the art and, in addition, many suitable resins are commercially available from resin manufacturers such as Cook Composites & Polymers Company.

[0022] Vinyl ester resins are generally prepared by reacting an epoxy resin with an unsaturated monobasic acid. Any known polyepoxides can be used in the production of vinyl ester resins. Unsaturated monobasic acids suitable for reaction with polyepoxides include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid and the like. The vinyl ester resins can be further modified, for example using maleic anhydride to introduce carboxyl groups, to increase the water dispersion / emulsion capacity. The production of vinyl ester resins is known to those skilled in the art and many suitable resins are commercially available from resin manufacturers such as Cook Composites & Polymers Company.

[0023] Polyurethane resin systems useful for making cured microparticles / nanoparticles are systems having an unsaturated bond in the polymer chain. Examples of polyurethane resin systems include urethane or polyurethane acrylates, which are reaction products of polyols, diisocyanates and hydroxyalkyl (meth) acrylates. Unsaturated polyester / urethane hybrid resin systems are similar to polyurethane resin systems, but unsaturated polyester / urethane hybrid resin systems contain unsaturated polyester polyols in the polymer chain.

[0024] Cross-linkable acrylics are based on polymerizable mixtures of acrylic monomers / oligomers containing cross-linkable molecules having a plurality of polymerizable groups in the molecule such as multifunctional monomers and / or (meth) acrylic oligomers. Particularly suitable cross-linkable acrylics for the present invention include polyester acrylates such as polycaprolactone diol or triol acrylates, urethane acrylates, epoxy acrylates, polyether acrylates, acrylic resin acrylates and mixtures thereof. Techniques for making cross-linkable acrylics are known in the coating industry.

[0025] The resin dispersion / emulsion should show stability over a period of time, since the resin dispersion / emulsion can be prepared and stored without directly carrying out steps (b) and (c) according to the invention. When using liquid resin systems to produce cured microparticles / nanoparticles, a dispersion / emulsion in water, a solvent or a combination of both can be prepared on site just before step (b) is carried out, since they can be easily dispersed or emulsified.

[0026] An ethylenically unsaturated monomer useful for making cured microparticles / nanoparticles can be an aromatic (vinyl), acrylate or methacrylate compound. The ethylenically unsaturated monomer can be any ethylenically unsaturated monomer suitable for crosslinking the unsaturated polyester resin by vinyl addition polymerization. Examples of useful ethylenically unsaturated monomers are styrene, o-, m-, p-methyl styrene, methyl acrylate, methyl methacrylate, (meth) acrylic acid, hydroxyl acrylate, t-butyl styrene, divinylbenzene, diallyl phthalate, triallulan cyanouranium and mixtures of two or more unsaturated monomers. The preferred monomer is styrene because it provides an economical monomer solution.

[0027] The monomer or monomer mixture can be added and mixed with the resin dispersion / emulsion when the resin dispersion / emulsion is used to form cured organic microparticles / nanoparticles in step (b). Cured organic microparticles / nanoparticles are prepared by conventional methods for curing thermosetting resins. A typical method for curing a thermosetting resin includes adding initiators and promoters to the resin or resin solution and (i) curing at an ambient temperature of about 25 ° C, or (ii) heating the substance to an elevated temperature to cure the resin. Typical curing conditions may be ambient temperature or up to 95 ° C in the case of dispersion in water or at least 5 ° C below the boiling point of the resin dispersion / emulsion when the resin dispersion is non-aqueous. The cured organic microparticles / nanoparticles in the dispersion can then be cured at an elevated temperature as described above for a certain period of time to further increase the degree of cure. Hardened organic microparticles / nanoparticles should have a degree of hardening (conversion) above 70%, preferably above 80%. The cured dispersion of nanoparticles should contain less than 0.5% by weight, preferably less than 0.3% by weight of free monomer measured by GC (gas chromatography).

[0028] Initiators useful in making the cured resin compositions of the invention are vinyl polymerization catalysts such as organic peroxides, persulfates, persulfates, perborates, percarbonates and azo compounds, or any other suitable catalyst capable of catalyzing the vinyl polymerization reaction of a polyol polyester and / or ethylenically unsaturated monomer . The initiators may be water-soluble or oil-soluble. Examples of several such catalysts are benzoyl peroxide (BPO), tert-butyl peroxybenzoate (TBPB), 2,2'-azo-bis-isobutyronitrile (AIBN), dibenzoyl peroxide, lauryl peroxide, di-t-butyl peroxide, a mixture of carbonate and diisopropyl peroxide t-butylperoxy-2-ethylhexanoate, potassium persulphate and ammonium persulphate. Promoters can also be used in combination with peroxide vinyl polymerization catalysts to control the degree of free radical initiation. A commonly used peroxide promoter is N, N-diethylaniline.

[0029] Mixing constants should be used for the resin / monomer dispersion / emulsion during the curing process. Mixing is necessary to control the temperature below the boiling point of the resin / monomer dispersion / emulsion, since the crosslinking reaction is exothermic. Mixing is also important to keep the cured microparticles / nanoparticles separate from each other during the reaction. Insufficient mixing will result in agglomeration or gelation of the nanoparticle dispersion. The cured organic microparticles / nanoparticles should have an average diameter of 10 to 1000 nanometers, preferably 20 to 500 and a viscosity of cured organic nanoparticles in water, solvent or a combination of both of less than 5000 mPa.s (cps). The cured organic suspension of nanoparticles is suspended in water, a solvent or a combination of both in any way and is stable without separation during storage.

[0030] The non-aqueous medium (of the second and final) of the resin according to the invention is a thermosetting resin system. The thermosetting resin system includes unsaturated polyester resin, crosslinkable acrylics, (poly) urethane acrylics, unsaturated polyester / polyurethane hybrid resin. The non-aqueous (second and final) resin medium can also be a polyol for the polyurethane resin. The non-aqueous resin medium according to the invention is usually produced in a batch process and may require the use of many stages of the synthesis process.

[0031] In the synthesis of unsaturated polyester resin, an organic suspension of nanoparticles in water is added to the reactor with other components at the beginning of the reaction. The reactor temperature is gradually increased to the boiling point of the resin mixture. The water / cosolvent of the resin dispersion / emulsion is removed from the resin medium when the water / cosolvent boils and is removed from the non-aqueous medium of the second resin. If the organic nanoparticle is suspended in an organic solvent, and this organic solvent is also a raw material in the synthesis of unsaturated polyester resin, the temperature can be increased directly to the esterification temperature. The synthesis takes place under normal conditions such as for the production of unsaturated polyester resin.

[0032] In the case where the unsaturated polyester resin is produced in several stages, the suspension of organic nanoparticles can be added to the reactor at a later stage. However, the reactor temperature should be lower than the boiling point of the organic nanoparticle suspension.

Water / cosolvent can be removed by distillation or by vacuum stripping. In the event that the organic nanoparticle is suspended in an organic solvent and the organic solvent also serves as a raw material in the synthesis of unsaturated polyester resin, the temperature can be directly raised to the esterification temperature and complete the synthesis of the resin in the usual way. Similar steps can be used in the synthesis of polyols for a polyurethane resin.

[0033] In the synthesis of crosslinkable acrylic resin or urethane acrylic resin, the suspension of organic nanoparticles is added to the non-aqueous medium of the second resin and all water / cosolvent is removed before adding the epoxide or diisocyanate. In the case where the organic nanoweed is suspended in an organic solvent, and this organic solvent serves as the raw material for the second resin, the reaction can be continued by carrying out the usual synthesis steps for cross-linkable acrylic resin or urethane acrylic resin.

[0034] The thermosetting resin system (second final resin) can be mixed or blended with one or more compatible unsaturated monomers, examples of suitable monomers are aromatic vinyl compounds such as styrene, alpha methyl styrene, dichlorostyrene, vinyl naphthalene, vinyl phenol, vinyl toluene, divinyl benzene etc. , unsaturated esters such as acrylic and methacrylic esters, vinyl laurate, etc., unsaturated acids, such as acrylic and alpha-alkylacrylic acids, butenoic acid, allylbenzoic acid, vinylbenzoic acid, etc., halides such as vinyl chloride, vinylidene chloride, nitriles such as acrylonitrile, methacrylonitrile, diolefins such as butadiene, isoprene, methylpentadiene polycarboxylic acids such as diallylphthalate, divinyl succinate, diallyl maleate, divinyl adipate, dichloroallyl tetrahydrophthalate, etc., and mixtures thereof.

[0035] This thermosetting resin system may additionally contain additives such as inhibitors and stabilizing agents generally known in the composite industry.

[0036] The amount of organic nanoparticles in the non-aqueous resin medium may be 2 to 30% by weight, preferably from 2 to 20%. The lower limit of the amount of organic nanoparticles in a resin environment is associated with the finding of the effect of organic nanoparticles on cured resin properties, such as mechanical properties. The upper limit of organic nanoparticles in this second resin medium is generally determined by the viscosity of this resin medium. The viscosity of the resin environment should be less than 5000 mPa.s (cps) when the maximum allowable amount of monomer is added. The monomer percentage in the final resin is in the range of 20 to 50% relative to the total weight of the resin, including monomer and microparticles / nanoparticles.

[0037] These microparticles / nanoparticles may contain / include groups reactive with this thermosetting resin during the synthesis of this resin medium in the presence of these microparticles / nanoparticles. Such groups, without limitation, may be hydroxyl, carboxyl, amino, epoxy groups.

[0038] This thermosetting resin system containing microparticles / nanoparticles is useful for a variety of applications. The nanoparticle can replace or partially replace fillers in composite materials. The use of microparticles / nanoparticles in thermosetting materials can increase mechanical strength, reduce porosity and increase the transparency of cured resin.

[0039] According to a preferred process according to the present invention, this first resin is selected from unsaturated polyester, vinyl ester, polyurethane, unsaturated polyester / urethane hybrid, crosslinkable acrylics, and this second resin system from unsaturated polyester resin suitable for crosslinking of acrylic, (poly) urethane acrylic, unsaturated polyester / polyurethane hybrid resin, vinyl esters and polyols for polyurethane resin.

[0040] The non-aqueous resin medium obtained using the claimed method can be used in a composite or cured coating composition.

[0041] Finally, an article may be produced containing or obtained from a non-aqueous resin medium obtained in accordance with the invention. More specifically, this article is obtained by curing a composite or coating composition (similar to gel coatings) as defined above. This article may advantageously be a composite article, more particularly a molded composite article or gel coating.

[0042] Unless otherwise indicated herein, the term "viscosity" refers to the viscosity of a polymer in a styrene monomer at 70 wt. NVM (non volatile substance, see below) at 25 ° C measured using a Brookfield viscometer.

[0043] The term "NVM" refers to a non-volatile substance dispersed in a volatile substance (e.g., a styrene monomer) measured in accordance with ASTM D1259.

[0044] The following examples show the steps for producing a resin containing a hardened organic nanoparticle.

Example 1 - Synthesis of organic nanoparticles [0045] In a glass container 100 grams of commercially available unsaturated polyester dispersion (STYPOL 0405022) containing 32% UPR in water and a cosolvent with 200 grams of deionized water, 14.6 grams of styrene monomer and 6.7 were mixed gram of surfactant ABEX EP-120 (Rhodia). The mixture was stirred using a magnetic stirrer for 10 minutes. The mixture was heated to 70 ° C on a hot plate with constant stirring using a magnetic stirrer. 0.11 gram of ammonium persulphate was dissolved in 3.0 grams of deionized water. The ammonium sulfate solution was added to the resin dispersion mixture in 4 portions with a 10-minute break. The resin dispersion was held at 70 ° C for a further 60 minutes with constant stirring using a magnetic stirrer. The resin dispersion obtained was a yellow transparent liquid. The residual styrene content of the resin dispersion was 0.05%. The resin dispersion formed a transparent film after removal of water from the resin dispersion. The membrane exhibited a residue exotherm of 12.8 J / g and a glass transition temperature of 62 ° C at DSC (temperature scan from -50 to 250 ° C at 10 ° C / min).

Example 2 - Synthesis of organic nanoparticles [0046] 50 grams of unsaturated polyester dispersion (type

NPG / DPG / IPA / MA / TMA, 32% NVM) with 100 grams of deionized water and 10.6 grams of styrene monomer. The mixture was stirred using a magnetic stirrer for 10 minutes.

The mixture was heated to 80 ° C on a hot plate while continuing to stir using a magnetic stirrer. 0.07 grams of ammonium persulphate was dissolved in 3.5 grams of deionized water. The ammonium persulfate solution was added to the resin dispersion mixture in 4 portions with a 10 minute interval. The resin dispersion was held at 80 ° C for a further 60 minutes while continuing to stir using a magnetic stirrer. The resin dispersion obtained was a yellow transparent liquid with an acid number of 6 and a viscosity of 1000 mPa.s. The average particle size of the resin dispersion was 80 nm. The remaining styrene content in the resin dispersion was 0.1%. The resin dispersion formed a transparent film after removal of water from the resin dispersion. The remaining solid showed a residue exotherm of 20.3 J / g and a glass transition temperature of 151 ° C at DSC.

Comparative Example 3 - Synthesis of resin without an organic nanoparticle [0047] To the flask equipped with a stirrer, a thermometer, a water separation column equipped with a reflux condenser and a nitrogen inlet, the following ingredients were added: grams of ingredients: neopentyl glycol 463, 2-butyl-2-ethyl- 1,3-propanediol 351, isophthalic acid 270, benzoic acid 38, maleic anhydride 423. The loaded mixture was subjected to a two-stage process and a total of 190 parts of water was distilled off. The reaction mixture was kept at 220 ° C until an acid number of 10-20 was obtained. The reaction mixture was then cooled to less than 140 ° C and the following ingredients were added: grams of toluhydroquinone 0.2 and styrene 590.

Example 4 - Synthesis of resin containing organic microparticles / nanoparticles [0048] To a two-liter flask equipped with a stirrer, a thermometer, a water separation column equipped with a reflux condenser and a nitrogen inlet, the following ingredients were added: grams of ingredients: neopentyl glycol 463, 2-butyl-2- ethyl-1,3-propanediol 351, dispersion of nanoparticles from Example 2: 556, benzoic acid 38, maleic anhydride 423. The loaded mixture was subjected to a two-stage process and a total of 596 parts of water were distilled off. The reaction mixture was kept at 220 ° C until an acid number of 10-20 was obtained. The reaction mixture was then cooled to less than 140 ° C and the following ingredients were added: grams of toluhydroquinone 0.2 and styrene 542.

Comparative Example 5 - Synthesis of polyester acrylic resin [0049] 427 grams of polycaprolactone triol (Tone ™ polyol 0301, Dow Chemical) and 680 grams of hexahydrophthalic anhydride was placed in a two-liter flask equipped with a stirrer, thermometer, nitrogen introducing tube and condenser. The temperature was increased to 115 ° C and held for 3 hours to produce a polyacid. Then 650 grams of glycidyl methacrylate, 0.2 grams of 2,3,5-trimethylhydroquinone and 0.8 grams of benzyltriethylammonium chloride were added. The atmosphere in the reactor was changed from nitrogen to nitrogen with 5% oxygen and the temperature was increased to 115 ° C and kept to an acid number below 20. Then 732 grams of styrene monomer and 0.2 gram of toluhydroquinone were added. The resulting polyester acrylic resin had a viscosity of 350 mPa.s (cP) at 70 wt. solids content in styrene.

Example 6 - Synthesis of polyester acrylic resin containing organic microparticles / nanoparticles [0050] In a two-liter flask equipped with a stirrer, thermometer, nitrogen introducing tube and condenser, 900 grams of the polyacid from comparative example 5 were placed, 406 grams of toluene, 406 grams of isopropyl alcohol and added to the flask 110 grams of commercially available unsaturated polyester resin (STYPOL 0400902, type NPG / BEPD / IPA / MA / BA, 30% styrene monomer) to produce a resin dispersion. The mixture was stirred well and the temperature was increased to 70 ° C, then 1.45 grams of 2,2'-azobis (2-methylbutyronitrile) (VAZO 67, DuPont) was added and kept at 70 ° C for 5 hours. The reactor temperature was slowly increased to 145 ° C to remove the solvent. Finally, a 25 inch vacuum was applied over 30 minutes. The reactor temperature was then reduced to 115 ° C and 530 grams of glycidyl methacrylate, 0.16 grams of toluhydroquinone and 0.8 grams of acryloxyethyltrimethylammonium chloride were added. The atmosphere in the reactor was changed from nitrogen to nitrogen with 5% oxygen and the temperature was increased to 115 ° C and maintained until the acid number was below 20.

Then 635 grams of styrene monomer and 0.2 grams of 2,3,5-trimethylhydroquinone were added. The resulting polyester acrylic resin had a viscosity of 1620 mPa.s (cP) at 70 wt. solids content in styrene.

Features of the microparticle / nanoparticle resin system [0051] Cast resin samples were made and the stretching, bending and HDT properties of the castings were measured in accordance with ASTM D-638, D-790 and D-648. Both stretching and bending properties were measured at ambient temperature at 25 ° C. The fracture strength at flat deformation and the critical strain energy release rate for samples 3 and 4 were measured in accordance with ASTM D-5045. The sample containing organic microparticles / nanoparticles showed better properties as shown in Table 1.

Table 1 - Viscosity and physical properties of resin samples

<td>Resin Example</td><td> 3</td><td> 4</td><td> 5</td><td> 6</td>

<td>NVM (%)</td><td> 70</td><td> 70</td><td> 70</td><td> 70</td>

<td>Viscosity mPa.s (cps)</td><td> 1500</td><td> 1800</td><td> 350</td><td> 1620</td>

<td>Tensile strength Mpa (psi)</td><td> 66,46</td><td> 66,33</td><td> 79,29</td><td> 71,57</td>

<td></td><td> (9640)</td><td> (9620)</td><td> (11500)</td><td> (10380)</td>

<td>Modulus of elasticity (kpsi)</td><td> 2,79 (405)</td><td> 3,33 (483)</td><td> 32,2 (467)</td><td> 34,54 (501)</td>

<td>Elongation (%)</td><td> 3,37</td><td> 2,65</td><td> 5,48</td><td> 5,27</td>

<td>Flexural strength (psi)</td><td> 107,76</td><td> 124,98</td><td> 132,38</td><td> 127,55</td>

<td></td><td> (15630)</td><td> (18127)</td><td> (19200)</td><td> (18500)</td>

<td>Fracture strength at flat deformation (MPa m^1/2)</td><td> 0,328</td><td> 0,552</td><td> -</td><td> -</td>

<td>Critical strain energy release rate (kJ / m²)</td><td> 0,122</td><td> 0,246</td><td> -</td><td> -</td>

<td>HDT (° C)</td><td> 86</td><td> 83</td><td> 74</td><td> 65</td>

CCP Composites US Representative:

PL-PAT-2012-87

EP 2 300 538 B1