JP2508117B2 - Method for producing dispersion of polymer particles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a stable dispersion of vinyl polymer particles, and more specifically, a dispersion stabilizer for a vinyl polymer having a siloxy group in its molecule. The present invention relates to a method for producing a stable dispersion of vinyl polymer particles, which is used as described above.

Problems to be Solved by Conventional Techniques and Inventions In recent years, in the field of automobile industry, plastics such as outer panels and parts have been made into plastics for the purpose of weight reduction, and the heat resistant temperature of plastics is low. There is a demand for lowering the baking temperature of the paint to be applied. Also, in order to save labor and shorten the assembly process, the steel plate that is the body of the automobile and the plastic parts such as the fender and bumper are pre-assembled, and the plastic part of the steel plate is coated with the same paint at the same time. A uni-painting system that finishes with a coating has also been adopted, and the development of paints that provide coating performance and finished appearance that are equal to or better than those of conventional automotive exterior paints and that are low-temperature cross-linking is urgently needed.

Conventionally, as the low temperature cross-linking type paint, a combination of a polyol type resin and a polyisocyanate, a combination of a compound having an acid or an acid anhydride group or a prepolymer and a polyfunctional epoxy resin has been studied, and some Some of them have been adopted, but all of them are two-component paints, and have a major drawback that the pot life is within several hours. Also, instead of the above polyisocyanate, it is possible to prepare a one-pack type by using a polyisocyanate blocked with a suitable blocking agent, but at present, the dissociation temperature of the blocking agent is high, so the target low temperature curing It cannot be a mold paint.

As described above, there is a demand for the rapid development of a one-component type coating composition which has excellent storage stability, can be cross-linked at low temperature, has good coating properties such as hardness and weather resistance, and has a good finished appearance.

MEANS TO SOLVE THE PROBLEMS Therefore, as a result of earnest research to obtain a coating material satisfying the above requirements, the present inventors have found that a polymerizable unsaturated group having both a polymerizable unsaturated group and a siloxy group in one molecule. In the presence of a dispersion stabilizer produced using a saturated monomer, by using a dispersion of polymer particles obtained by dispersion polymerization of an unsaturated monomer in an organic liquid, the above requirements are satisfied. The inventors have found that they can be made and have reached the present invention.

That is, in the present invention, in the presence of a dispersion stabilizer resin which is a high molecular weight polymer, the monomer is dissolved but polymer particles obtained by dispersion polymerization of the monomer are dissolved in an organic liquid insoluble. In the method for producing a dispersion liquid of polymer particles obtained by dispersion polymerization of a monomer, the dispersion stabilizer resin is represented by at least one polymerizable unsaturated group and at least one of the following formulas in one molecule. , A siloxy group bonded to a carbon atom However, R ₁ , R ₂ : C _{1 to} C ₁₈ alkyl group, phenyl group, allyl group, Cl, H, FR ₃ : C _{1 to} C ₁₈ alkyl group, phenyl group, allyl group 5 to 60% by weight of the saturated monomer (A),
Number average molecular weight 1, which is obtained by copolymerizing the monomer (A) with 95-40% by weight of a polymerizable unsaturated monomer (B)
A siloxy group-containing copolymer of 000 to 35,000 and / or a modified product obtained by introducing a radical-polymerizable unsaturated double bond into the copolymer is used, and the monomer to be dispersion-polymerized is one kind. Alternatively, it relates to a method for producing a polymer particle and a dispersion liquid, which are characterized in that they are two or more kinds of ethylenic illegal monomers. The dispersion liquid of the polymer particle obtained by the method of the present invention is a continuous phase of the dispersion liquid. A siloxy group present in a dispersion stabilizer is hydrolyzed by water in the presence of a catalyst as shown by the following formula: After the coating or just before the coating, the water in the air generates hydroxyl groups in the polymer, and this is reacted with a cross-linking agent.By using a low-temperature cross-linking type polyisocyanate as the cross-linking agent, low-temperature cross-linking is possible. It is possible to provide a one-component paint having good properties.

The polymerizable unsaturated monomer (A) which is a component of the siloxy group-containing copolymer in the present invention is, for example, trialkylchlorosilane or triphenylchlorosilane in the presence of a hydrochloric acid scavenger such as triethylamine or pyridine. , Triallylchlorosilane, dialkylchlorosilane, dialkyldichlorosilane, or dialkylhydrosilane is referred to as those obtained by reacting with a hydroxyl group-containing vinyl-based monomer as described below. Trimethylsiloxyethyl (meth) acrylate, trimethylsiloxypropyl (meth) acrylate, trimethylsiloxybutyl (meth) acrylate,
Examples thereof include triethylsiloxyethyl (meth) acrylate, tributylsiloxypropyl (meth) acrylate, triphenylsiloxyalkyl (meth) acrylate and the like. These can be used alone or as a mixture of two or more kinds.

Examples of the hydroxyl group-containing vinyl monomer include hydroxyalkyl (meth) acrylates such as β-hydroxyethyl (meth) acrylate, β-hydroxypropyl (meth) acrylate or β-hydroxybutyl (meth) acrylate, or N-methylolated ( (Meth) acrylamide; β-hydroxyethyl (meth) acrylate to which ε-caprolactone is added [for example, Praxel FM, FA series (manufactured by Daicel Chemical Industries, Ltd.) or TONE ^TM M-100 (manufactured by Union Carbide)] Blemmer PP-1000 represented by the common name polypropylene glycol monomethacrylate and Blemmer PE series represented by the common name polyethylene glycol monomethacrylate (both manufactured by NOF CORPORATION); (meth) acrylic acid, maleic acid, fumaric acid And unsaturated carboxylic acids, such as itaconic acid, "Cardura E"
(Manufactured by Shell Kagaku Co., glycidyl ester of branched fatty acid), monoglycidyl ester of monovalent carboxylic acid such as glycidyl octylate or coconut oil fatty acid glycidyl ester, or monoglycidyl ethers such as butyl glycidyl ether. A typical example is an adduct with a typical monoepoxy compound.

In order to produce a siloxy group-containing copolymer by copolymerizing with the polymerizable unsaturated monomer (A), typical examples of the polymerizable unsaturated monomer (B) include 1 carbon atom. ~ 22 having an alkyl group in the side chain, styrene, vinyltoluene, t-butylstyrene, α-methylstyrene, glycidyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, (meth) acrylonitrile Unsaturated carboxylic acids such as cyclohexyl (meth) acrylate, (meth) acrylic acid, maleic acid, fumaric acid or itaconic acid, diesters of maleic acid or fumaric acid with C _{1 to} C ₁₈ monohydric alcohols, ( (Meth) acrylamides such as (meth) acrylamide or N-alkoxymethylated (meth) acrylamide, N, N Dialkylaminoalkyl (meth) acrylates, or phosphoric acid group-containing (meth)
There are acrylates, vinyl acetate, fluorinated vinyl monomers such as hexanefluoropropylene, tetrafluoroethylene, etc., which may be used alone or in combination with the polymerizable unsaturated monomer (A) depending on the desired coating film performance. Used as a mixture of two or more species.

The blending ratio of the polymerizable unsaturated monomer (A) and (B) is preferably 5 to 60% by weight of the polymerizable unsaturated monomer (A),
It is preferably 5 to 40% by weight, the polymerizable unsaturated monomer (B) is the rest, and 95 to 40% by weight is preferable, and 95 to 60% by weight is preferable. When the compounding amount of the polymerizable unsaturated monomer (A) is less than 5% by weight, the polymerizable unsaturated monomer (A) is
The effect of the compounding is not sufficient, and if it is used in excess of 60% by weight, the hydroxyl value of the dispersion stabilizer after hydrolysis becomes too large, and problems such as poor moisture resistance of the obtained coating film occur.

In the present invention, in order to obtain a siloxy group-containing copolymer which is a dispersion stabilizer as it is or is modified to be a dispersion stabilizer, the polymerizable unsaturated monomer (A) as described above,
It can be carried out by a known and conventional method using (B), for example, a solution polymerization method using a radical generator.

As the radical generator, any of those usually used for the polymerization of acrylic monomers can be used, but among them, representative ones include azobisisobutyronitrile and di-tert-butyl. Peroxides or benzoyl peroxides and the like, and as the solvent, aromatic hydrocarbons such as toluene or xylene; acetic ester systems such as ethyl acetate, butyl acetate or cellosolve acetate; ketones such as methyl ethyl ketone or methyl isobutyl ketone. A system; an alcohol system such as butanol or isobutanol; or a cellosolve system such as methyl cellosolve or ethyl cellosolve can be used. However, when the dispersion of the polymer particles obtained by the method of the present invention is used as a mixture with a polyisocyanate having a free isocyanate group as a crosslinking agent, for example, in order to have a grafting active point in the dispersion stabilizer, In the case where an active unsaturated isocyanate is used, the above-mentioned solvents should not be used since the alcohol-based ones have reactivity with the isocyanate group.

If necessary, mercaptans, α-methylstyrene and “dipentene T” (products of Nippon Terpene Chemical Co., Ltd.)
It is also possible to use a commonly used chain transfer agent such as, for example.

The siloxane group-containing copolymer thus obtained preferably has a number average molecular weight (n) of 1,000 to 35,000,
More preferably, n ranges from 3,000 to 15,000. When n of this copolymer is less than 1000, in the obtained dispersion liquid of polymer particles, the steric repulsion force between particles is insufficient, particles are easily aggregated and settled, and an unstable dispersion liquid is obtained. Will end up. On the other hand, when n exceeds 35,000, it tends to be difficult to dissolve in the organic liquid that is the dispersion solvent, and the viscosity of the dispersion liquid of the polymer particles tends to be significantly high.

The siloxy group-containing copolymer described above can be used as a dispersion stabilizer in the present invention by itself, but the copolymer molecule has an average of 0.1 to 1.5 radical-polymerizable unsaturated double bonds per molecule. Is preferable, and a modified product introduced within the range of 0.3 to 1.0 is more preferable as the dispersion stabilizer. Because the introduced radically polymerizable unsaturated double bond acts as a grafting active point with the polymer particles during the dispersion polymerization, it is possible to improve the storage stability and mechanical stability of the resulting dispersion of polymer particles. This is because. If the average number exceeds 1.5 per molecule, the proportion of the polymer having a plurality of double bonds in one molecule of the dispersion stabilizer increases, and viscosity and gelation are likely to occur during dispersion polymerization.

Various methods are available for introducing a radically polymerizable unsaturated double bond into a siloxy group-containing copolymer molecule.
For example, an epoxy-containing unsaturated monomer such as glycidyl (meth) acrylate is added to the carboxyl group of the copolymer prepared by using a part of the polymerizable unsaturated monomer (B) such as acrylic acid or methacrylic acid. Reacting with a tertiary amine such as dimethylaminoethanol as a catalyst to add
On the contrary, a method of reacting and adding a carboxyl group-containing unsaturated monomer to an epoxy group in the copolymer, and a hydroxyl group of a copolymer prepared by using a small amount of a hydroxyl group-containing unsaturated monomer. An isocyanate-containing unsaturated monomer such as isocyanate ethyl acrylate can be reacted with and added to.

Such combinations may include other acid anhydride groups and hydroxyl groups, acid anhydride groups and mercapto groups, and the like. The general conditions under which addition reactions occur between such reactive group combinations are well known, and the temperatures at which those reactions occur are dependent upon the particular combination of reactive groups selected, and by the use of catalysts. It goes without saying that it can be modified.

In addition, an allyl group was introduced into the copolymer using an azo catalyst that partially used allyl methacrylate when preparing the copolymer, and a peroxide catalyst such as benzoyl peroxide was used during dispersion polymerization. By taking such a measure, the allyl group can be used as the graft active site.

Further, a point to be noted in designing the dispersion stabilizer resin in the present invention is that the polymer particles are generally insoluble in the organic liquid used at the time of dispersing the polymer particles, and therefore, the aliphatic hydrocarbon solvent is generally used. Although a mixed solvent mainly composed of a solvent having low polarity such as is used, the dispersion stabilizer resin needs to be dissolved in this solvent system, and thus is close to the polarity (solubility parameter etc.) of this solvent system, that is, It should be designed to be a polymer with low polarity.

Hydroxyl group in the dispersion stabilizer resin, when containing a group such as a carboxyl group, the polarity becomes higher, but in the present invention, instead of the hydroxyl group, because it uses a siloxy group to be a hydroxyl group by hydrolysis, It has the advantage that the polarity can be kept very low.

However, in order to suppress the polarity of the dispersion stabilizer resin to a low level, alcohol of 10% by weight or more, more preferably 30% by weight or more of the polymerizable unsaturated monomer (B) component at the time of preparing the copolymer is used. It is preferable to use (meth) acrylic acid esters having 4 or more carbon atoms in the component part.

The above-mentioned dispersion stabilizer resin used in the present invention may be used alone or in combination of two or more kinds having different copolymerization compositions and molecular weights. Further, if necessary, other dispersion stabilizers such as , Alkyd resin, acrylic resin, poly
It is also possible to use it together with a small amount of a graft polymer of 12-hydroxystearic acid and an acrylic resin, a cellulose derivative or the like.

According to the present invention, one or more ethylenically unsaturated monomers are dispersion-polymerized in an organic liquid in the presence of a dispersion stabilizer resin as described above.

The dispersion polymer particles produced by the polymerization are not substantially dissolved in the organic liquid used for the polymerization, but the dispersion stabilizer resin solution is combined with the organic solvent to disperse the dispersion stabilizer resin and the ethylenic unsaturated A good solvent for monomers,
Organic liquids are included.

Specific examples of such an organic liquid include hexane, heptane, octane, and other aliphatic hydrocarbons; benzene, toluene, xylene, and other aromatic hydrocarbons; alcohol-based, ether-based, ester-based, and ketone-based solvents such as isopropyl alcohol. n-butyl alcohol, i-butyl alcohol, octyl alcohol, cellosolve, butyl cellosolve, diethylene glycol monobutyl ether,
Methyl isobutyl ketone, diisobutyl ketone, ethyl acyl ketone, methyl hexyl ketone, ethyl butyl ketone, ethyl acetate, isobutyl acetate, acyl acetate, 2-
Examples thereof include ethylhexyl acetate and the like, and these may be used alone or in combination of two or more, but generally, they are mainly aliphatic hydrocarbons,
In addition to this, aromatic hydrocarbons and alcohols as described above,
A combination of ether-based, ester-based or ketone-based solvents is preferably used. Furthermore, trichlorotrifluoroethane, metaxylene hexafluoride, tetrachlorohexafluorobutane, etc. can be used if necessary.

When an isocyanate compound such as polyisocyanate is used as a cross-linking agent for the polymer particle dispersion obtained by the method of the present invention, use of a hydroxyl group-containing solvent such as alcohol or cellosolve should be avoided.

The ethylenically unsaturated monomer that can be polymerized in the presence of the dispersion stabilizer resin and the organic liquid described above is not particularly limited as long as it is a radically polymerizable unsaturated monomer, and various types can be used. However, the typical ones are as follows.

(A) Ester of acrylic acid or methacrylic acid: for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, methacrylic acid. ethyl, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, C ₁ ~ ₁₈ alkyl esters of methacrylic acid octyl, acrylic acid or methacrylic acid lauryl methacrylate; glycidyl acrylate, glycidyl methacrylate; allyl acrylate, C ₂ ~ ₈ alkenyl esters of acrylic or methacrylic acid and allyl methacrylate; hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxy-flop Pills acrylate, C ₂ ~ ₈ hydroxyalkyl esters of acrylic acid or methacrylic acid such as hydroxyethyl methacrylate; allyl oxyethyl acrylate, acrylic acid or C ₃ ~ ₁₈ alkenyloxyalkyl esters of methacrylic acid such as allyloxy methacrylate.

(B) Vinyl aromatic compound: For example, styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, vinylpyridine.

(C) α, β-ethylenically unsaturated acids: eg acrylic acid, methacrylic acid, itaconic acid.

(D) Polyfunctional unsaturated monomer for intra-particle crosslinking:
For example, divinylbenzene, ethylene glycol di (meth) acrylate.

(E) Siloxy group-containing unsaturated monomer: The polymerizable unsaturated monomer (A) used for producing the dispersion stabilizer resin can be used.

(F) Others: acrylonitrile, methacrylonitrile, methyl isopropenyl ketone; vinyl acetate, veova monomer (shell chemical product), vinyl propionate,
Vinyl pivalate etc.

Particularly suitable among these monomers are monomers or monomer mixtures containing at least 40% by weight of esters of acrylic acid or methacrylic acid. Further preferably, C ₁
At least a (meth) acrylate having a C ₄ side chain
It is a monomer or monomer mixture containing 30% by weight.

The above-mentioned monomers are polymerized by using a radical polymerization initiator. As the radical polymerization initiator that can be used,
For example, azo initiators such as 2,2′-azoisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile); benzoyl peroxide, lauryl peroxide, tert-butyl peroctoate, etc. Examples of the peroxide-based initiators, these polymerization initiators are generally 0.2 to 10 parts by weight, preferably 100 parts by weight of the monomers to be subjected to polymerization.
It can be used within the range of 0.5 to 5 parts by weight.

Further, the amount of the dispersion stabilizer resin used can be varied over a wide range depending on the type of the resin, etc., but generally 5 to 70% by weight based on the total amount of the monomer to be polymerized and the dispersion stabilizer. , Preferably in the range of 10-60% by weight.

Further, the total concentration of the monomer and dispersion stabilizer in the organic liquid is generally 30 to 70% by weight, preferably 30 to 60% by weight.

The polymerization can be carried out by a method known per se, and the reaction temperature during the polymerization can be generally in the range of 60 to 160 ° C., and the reaction can be usually completed in 1 to 15 hours.

The polymer particle portion of the dispersion liquid obtained by the method of the present invention may be pre-crosslinked in the dispersion liquid or may be in a non-crosslinked state.

Further, when the polymer particles are pre-crosslinked, the amount of the cross-linking agent such as polyisocyanate used for cross-linking the dispersion is sufficient to cross-link the dispersion stabilizer resin which is a continuous phase, since the polymer particles are already cross-linked. A sufficient amount is enough. For this reason, when an expensive material such as polyisocyanate is used as the crosslinking agent, it is more cost effective to crosslink the polymer particles.

As a method of pre-crosslinking the polymer particle portion, as the ethylenically unsaturated monomer during dispersion polymerization, a method of using a small amount of another functional unsaturated monomer such as divinylbenzene, glycidyl methacrylate or the like. A small amount of an epoxy group-containing unsaturated monomer and a carboxyl group-containing unsaturated monomer such as acrylic acid is used as a monomer during dispersion polymerization, and dispersion polymerization is performed in the presence of a catalyst such as a tertiary amine. Methods etc. can be used.

The dispersion liquid of the polymer particles produced by the method of the present invention described above has extremely excellent dispersion stability and can be used not only for coating materials but also for molded articles, adhesives, fillers and the like. .

The dispersion liquid provided by the present invention can be used as it is, but it is preferable to add a crosslinking agent from the viewpoint of coating film performance.

As the cross-linking agent, polyisocyanates are most preferable from the viewpoints of low-temperature cross-linking property, coating performance, etc., but aminoplasts can also be used for applications that do not require low-temperature cross-linking property.

Typical polyisocyanates include aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate or xylylene diisocyanate; aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate or trimethylhexane diisocyanate;
Isophorone diisocyanate, methylcyclohexane-
2,4- (or 2,6-) diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate) or
Alicyclic diisocyanates such as 1,3-di (isocyanatomethyl) -cyclohexane, and each of these diisocyanates, with polyhydric alcohols such as ethylene glycol, propylene glycol, neopentyl glycol or trimethylolpropane; reacting with isocyanate groups A polyester resin having an extremely low molecular weight having a functional group (including oil-modified type) or an adduct with water, a burette, or a polymer of the above-mentioned diisocyanates (including an oligomer). is there. Then, as the compounding ratio of these polyisocyanates and the dispersion liquid of the polymer particles produced by the method of the present invention, OH / NCO including the OH group generated by hydrolysis of the siloxy group is 1 / 0.2 to The range of 1/3 (equivalent ratio) is preferable from the viewpoint of coating film performance.

In this case, the method of using the one-pack type in which the polyisocyanate is preliminarily blended is in accordance with the object of the invention, but the two-pack type blended immediately before coating can of course be used.

When polyisocyanate is used as a cross-linking agent and used in a one-pack type, a hydroxyl group that reacts at low temperature with polyisocyanate in a resin and an organic liquid in a dispersion liquid of polymer particles obtained by the method of the present invention as described above. It is preferable not to have from the viewpoint of storage stability.

As aminoplast, a known butylated melamine,
Methylated melamine, butyl / ethyl mixed etherified melamine, urea-formaldehyde resin and the like can be used.

The amount of aminoplast used is preferably 10 to 40% by weight based on the resin solid content of the dispersion liquid of the polymer particles produced by the method of the present invention. Further, a curing accelerator for aminoplast, for example, an acid catalyst such as paratoluenesulfonic acid may be added to increase the crosslinkability. The amount of the curing accelerator used is 0.1 to 10 with respect to the resin solid content.
Weight percent is preferred.

The dispersion of polymer particles obtained by the method of the present invention reacts with moisture in the air to hydrolyze the siloxyl group bonding portion to form a hydroxyl group capable of reacting with the curing agent. It is preferred to use a catalyst to accelerate this hydrolysis. Examples of the catalyst include phosphoric acid, phosphoric acid ester, phosphorous acid ester, unsaturated group-containing phosphoric acid ester, p-toluenesulfonic acid and its amine salt, benzoic acid, trichloroacetic acid, trifluoroacetic acid, naphthalenedisulphonic acid and its amine salt. Acid catalyst, ethylenediamine,
Amines such as N-β-aminoethyl-γ-aminopropyltrimethoxysilane, butylamine, dibutylamine, t-butylamine, hexylamine and triethylamine, alkyl titanates, octylates, dibutyltin diacetate, dibutyltin dilaurate. , And metal salts of carboxylic acids such as lead octylate, sulfide-type compounds such as monobutyltin sulfite and dioctyltin mercaptide, mercapto-type organotin compounds, tetraethylammonium fluoride, and compounds producing fluorine ions such as cesium fluoride are effective. is there. The amount of these curing catalysts added is 0.001 to 10% by weight, preferably 0.0
It is recommended to use 05-8% by weight.

When the dispersion of polymer particles obtained by the method of the present invention is made into a one-pack type together with a crosslinking agent such as polyisocyanates, in order to ensure long-term storage stability, conversion of siloxy groups into hydroxyl groups is not caused. Is necessary
For this purpose, it is only necessary to capture a small amount of water that enters for some reason. That is, the addition of a water binder having reactivity with water is advantageous for ensuring long-term stability. Further, this water-binding agent may be used by mixing it in advance when producing a siloxy group-containing copolymer. Examples of the water-binding agent having reactivity with water include alkyl orthoformates such as trimethyl orthoformate, triethyl orthoformate and tributyl orthoformate; trialkyl orthoacetates such as trimethyl orthoacetate, triethyl orthoacetate and tributyl orthoacetate. Trialkyl orthoborate such as tributyl orthoborate, triethyl orthoborate; tetramethyl silicate, tetraethyl silicate, tetrabutyl silicate, tetra (2)
-(Methyl) ethyl silicate or tetra (2-chloroethyl) silicate, such as tetra (substituted) alkyl silicates alone; tetraphenyl silicate, tetrabenzyl silicate and the like tetra (substituted) alkyl silicates of the same effect substances (hereinafter, the same effect) Abbreviated as simple substance); or tetraethyl silicate dimer, trimer, tetramer, or hexamer "ethyl silicate 40" (a product of Colcoat, a tetramer of tetraethyl silicate, a mixture of pentamer and hexamer)
Hydrolysable ester compounds such as tetra (substituted) alkyl silicates alone, condensates of the same effective silicates, phenyl isocyanate, p-
There are compounds having an isocyanate group such as chlorophenyl isocyanate, benzenesulfonyl isocyanate, p-toluenesulfonyl isocyanate, and isocyanate ethyl methacrylate (NCO group-containing monomer manufactured by Dow Chemical Co.).

The amount used is 0.1 to 30% by weight, preferably 0.5 to 20% by weight, based on the resin solid content.

When the polymer particle dispersion obtained by the method of the present invention is used for applications such as paints, in addition to the above and the above, if necessary, a pigment, a plasticizer and a deterioration inhibitor, a leveling agent, an ultraviolet absorber Various conventional additives such as agents and pigment dispersants can be added.

In addition, other compatible resins may be mixed and used.

As described above, the dispersion of polymer particles obtained by the method of the present invention can be used in various ways, but the method of the present invention for maximizing the capacity of the dispersion is a crosslinking agent. As a combination with polyisocyanate,
This is a method used as a one-pack paint.

The one-pack type coating thus obtained can be applied by a conventional method such as brush coating, spray coating or roll coating, and is excellent in storage stability. As a curing method, a wide range from room temperature drying to heat drying can be used. The optimum curing conditions can be set with, but 70
By heating at a low temperature of about 80 ° C for 20 to 30 minutes, a coating film having excellent coating film physical properties such as hardness, adhesion and weather resistance and a good finished appearance can be obtained.

Next, the present invention will be specifically described with reference to Reference Examples, Examples, and Comparative Examples. In the following, all “parts” and “%” are based on weight unless otherwise specified.

Synthesis of Dispersion Stabilizer Varnish Synthesis Example 1 (Synthesis of Dispersion Stabilizer [I] Liquid) A four-necked flask equipped with a stirrer, an inert gas inlet, a thermometer and a cooler was charged with xylol 500 parts and butyl acetate 300 parts. Charge and heat up to 110 ° C while blowing N ₂ gas little by little, then, trimethylsiloxyethyl methacrylate 300 parts styrene 100 parts n-butyl acrylate 160 parts methyl methacrylate 150 parts 2 ethylhexyl methacrylate 280 parts acrylic acid 10 parts azobis A mixture of 10 parts of isobutyronitrile (mixture of monomer and polymerization initiator) was added to 4 parts.
The mixture was added dropwise over a period of time and then aged for 30 minutes, and then a mixture of 200 parts of butyl acetate and 5 parts of azobisisobutyronitrile was added dropwise over a period of 1.5 hours and aged for 30 minutes.

Subsequently, 0.15 parts of para-tertiary butyl catechol, 16 parts of glycidyl methacrylate, and 0.8 parts of dimethylaminoethanol were added, and after heating for 5 hours, the reaction was terminated by cooling to obtain a dispersion stabilizer [I] liquid.

This product has a non-volatile content of 50% and a Gardner viscosity of P to Q.
(25 ° C), weight average molecular weight approximately 17,000 (number average molecular weight approximately
8000), having a hydroxyl value of 42 based on siloxy groups, and having an average of about 0.7 polymerizable double bonds per molecule.

Synthesis Example 2 (Synthesis of Dispersion Stabilizer [II] Liquid) The same reaction as in Synthesis Example 1 was performed except that the following mixture was used as the “monomer and the polymerization initiator”.

Trimethylsiloxyethyl methacrylate 300 parts Styrene 200 parts n-Butyl acrylate 190 parts 2 Ethylhexyl acrylate 300 parts Acrylic acid 10 parts Azobisisobutyronitrile 30 parts The obtained dispersion stabilizer [II] liquid has a nonvolatile content of 50%, Gardner Viscosity LM (25 ℃), weight average molecular weight about 13,000
It had a number average molecular weight of about 6000, a hydroxyl value of 42 based on siloxy groups, and had an average of about 0.7 polymerizable double bonds per molecule.

Synthesis Example 3 (Synthesis of Dispersion Stabilizer [III] Solution) The same procedure as in Synthesis Example 1 was repeated except that triphenylsiloxyethyl methacrylate was used instead of trimethylsiloxyethyl methacrylate in Synthesis Example 1. ] Liquid was obtained. This is non-volatile 50
%, Gardner viscosity R to S (25 ° C), weight average molecular weight approx.
It had a hydroxyl number of 22 based on a siloxy group of 18,000 (number average molecular weight of about 8,000), and had an average of about 0.7 polymerizable double bonds per molecule.

Synthesis Example 4 (Synthesis of Dispersion Stabilizer [IV] Liquid Having No Siloxy Group) In Synthesis Example 1, 193 parts of 2-hydroxyethyl methacrylate is used instead of 300 parts of trimethylsiloxyethyl methacrylate, and 500 parts of xylol are used. , Instead of 300 parts of butyl acetate, 446 parts of xylol, 268 parts of butyl acetate
Butyl acetate 179 instead of 200 parts butyl acetate
A dispersion stabilizer [IV] liquid having no siloxy group was obtained in the same manner except that a part was used. This is non-volatile 50
%, Gardner viscosity OP (25 ° C), weight average molecular weight approx.
16,000 (number average molecular weight about 7,000), hydroxyl value 42,
It had an average of about 0.7 polymerizable double bonds per molecule.

Example 1 (Preparation of Dispersion [A]) A four-necked flask equipped with a stirrer and a condenser was charged with 300 parts of the 50% dispersion stabilizer “I” solution obtained in Synthesis Example 1 390 parts of heptane and 50 parts of butyl acetate. Charge the mixture, heat to 90 ° C, and heat it to a mixture of styrene 50 parts methyl methacrylate 200 parts acrylonitrile 50 parts hydroxyethyl methacrylate 50 parts azobisisobutyronitrile 3.5 parts for 4 hours. After aging for 30 minutes, a mixture of 70 parts of butyl acetate and 1.75 parts of azobisisobutyronitrile was added dropwise over 1.51 hours, and after aging for 30 minutes, the reaction was finished by cooling.

The resulting dispersion is a white, stable dispersion with a non-volatile content of 43%, Gardner viscosity D to E (25 ° C.),
The average particle size (measured by a light scattering method) was 280 nm. The polymer particles in the dispersion were not crosslinked and the particles readily dissolved when a small amount of the dispersion in acetone was added.

Example 2 (Preparation of dispersion liquid [B]) The same reaction as in Example 1 was carried out except that the following mixture was used as the monomer and the polymerization initiator.

Styrene 50 parts Methyl methacrylate 256 parts Acrylonitrile 30 parts Glycidyl methacrylate 7 parts Methacryl 7 parts Azobisisobutyronitrile 3.5 parts The resulting dispersion has a non-volatile content of 43%, Gardner viscosity (25 ° C) C to D, average particle size. It was a stable polymer particle dispersion liquid of 230 nm.

The polymer particles in this dispersion were highly crosslinked gelled fine particles, and even when diluted with a polar solvent such as acetone or methyl ethyl ketone, the particles did not dissolve or swell.

Example 3 (Preparation of Dispersion [C]) 50% dispersion obtained in Synthesis Example 2 was placed in a four-necked flask equipped with a stirrer and a cooler, using the same apparatus used for the synthesis of non-aqueous dispersion [A]. Stabilizer [II] solution 300 parts Heptane 440 parts were charged, and at 900 ° C., a mixture of butylene 75 parts methyl methacrylate 200 parts acrylonitrile 25 parts hydroxypropyl methacrylate 50 parts azobisisobutyronitrile 3.5 parts was added dropwise over 4 hours. Then, a mixture of 70 parts of butyl acetate and 1.75 parts of asobisisobityronitrile was added dropwise over 1.5 hours, and after aging for 30 minutes, 160 parts of heptane were recovered under reduced pressure and the solution was concentrated. did.

The resulting dispersion has a non-volatile content of 50% and a Gardner viscosity of L.
.About.M (25.degree. C.), and it was a stable polymer particle dispersion liquid having an average particle size of 320 nm.

The polymer particles were not crosslinked and the particles dissolved readily when a small amount of the dispersion was placed in acetone.

Example 4 (Preparation of Dispersion [D]) The same as Example 1 except that the 50% dispersion stabilizer [I] solution was replaced by the 50% dispersion stabilizer [III] obtained in Synthesis Example 3. And a stable white dispersion liquid [D] was obtained. This dispersion [D] had a non-volatile content of 43%, a Gardner viscosity of EF (25 ° C.), and an average particle size of dispersed particles of 280 μm. The polymer particles in the dispersion were not crosslinked and the particles readily dissolved when a small amount of the dispersion in acetone was added.

Comparative Example 1 (Preparation of dispersion liquid [E] having no siloxy group) In Example 1, instead of the 50% dispersion stabilizer [I] liquid, the 50% dispersion stabilizer [IV] liquid obtained in Synthesis Example 4 was used. The same procedure was performed except that the above was used to obtain a white stable dispersion liquid [E]. This dispersion [E] had a nonvolatile content of 43%, Gardner viscosity D to E (25 ° C.), and the average particle size of dispersed particles was 280 μm. The polymer particles in the dispersion were not crosslinked and the particles dissolved readily when a small amount of the dispersion was placed in acetone.

Comparative Example 2 400 parts of isobutyl acetate and 400 parts of toluene were heated to reflux, the following monomers and polymerization initiators were added dropwise over 3 hours, and aging was carried out for 2 hours after the addition.

2-Hydroxyethyl methacrylate 200 parts Methyl methacrylate 400 parts Ethyl acrylate 300 parts Butyl acrylate 100 parts 2,2'-Azobisisobutyronitrile 2 parts The resulting allyl resin solution has a nonvolatile content of 55% and an OH value of 4
8. The viscosity was J and the weight average molecular weight was about 16,000 (number average molecular weight about 7,000).

Comparative Example 3 400 parts of isobutyl acetate and 400 parts of toluene were heated to reflux, the following monomers and polymerization initiators were added dropwise over 3 hours, and after the addition, aging was carried out for 2 minutes.

2-Hydroxyethyl methacrylate 170 parts Styrene 100 parts Isobutyl methacrylate 520 parts 2-Ethylhexyl methacrylate 200 parts Methacrylic acid 10 parts 2,2'-Azobisisobutyronitrile 2 parts The resulting acrylic resin solution has a nonvolatile content of 55%, OH value 4
1, viscosity I and weight average molecular weight were about 16,000 (number average molecular weight about 7,000).

Preparation Examples 1 to 8 and Comparative Preparation Examples 1 to 4 In order to evaluate the physical properties and the like of the dispersions or resin solutions obtained in Examples 1 to 4 and Comparative Examples 1 to 3, conventional paints having the formulations shown in Table 1 were used. A paint was prepared according to the chemical method.

Preparation of coated plate for coating film performance test On 0.8 mm thick dull steel sheet which has been subjected to zinc phosphate chemical conversion treatment, epoxy cationic electrodeposition coating is electrodeposited to a dry coating film thickness of about 20μ and baked at 170 ° C for 20 minutes After polishing with # 400 sandpaper, wipe it with petroleum benzine to degrease it, then air-spray an intermediate coating surfacer for automobiles to a dry coating film of about 25μ, and bake at 140 ° C for 30 minutes. It was sanded with sandpaper, drained and dried. Then, it was degreased with petroleum benzine and used as a test material.

On the material for this test, the paints prepared in Preparation Examples 1 to 8 and Comparative Preparation Examples 1 to 4 were viscous for 22 seconds (Ford cup # 4/25 ° C), and a dry film thickness was obtained with an air spray gun. It was painted to a thickness of about 30μ, set at room temperature for 10 minutes, and then baked and cured in an electric hot-air baking oven. Regarding the baking conditions, only the paint of Preparation Example 6 was baked at 140 ° C for 30 minutes, and the other paints were baked at 80 ° C for 30 minutes.

Table 1 shows the results of the coating film performance test of the obtained baked coated plate and the results of the storage stability test of the diluted paint having a viscosity of 22 seconds (Ford cup No. 4/25 ° C). The coating film performance test was conducted 3 days after preparation of the coated plate.

 The notes in Table 1 are as follows.

(* 1) Vernock DN-999: Non-yellowing type polyisocyanate prepolymer manufactured by Dainippon Ink and Chemicals, Inc. (* 2) Cymel 303: Methylated melamine resin manufactured by Mitsui Toatsu Chemicals, Inc. (* 3) Ethyl silicate 40: Mixture of tetraethyl silicate partial condensate manufactured by Nippon Corcoat Co., Ltd. (* 4) TYPURE R-960: DuPont rutile titanium oxide (* 5) Number of times of solvent rubbing: xylene-impregnated four cases It was set on the rubbing bar of a rubbing tester, and the coated plate surface was reciprocated at the same place for a length of about 5 cm with a load of 4 kg / cm ² , and the number of reciprocations until the intermediate coating surfacer coating film appeared was displayed.

(* 6) Impact resistance: According to JIS K 5400, it was performed in an atmosphere of 20 ° C. Load 500g, diameter of the tip of the target is 1/2
Indicates the maximum height that does not cause coating damage in inch conditions (c
m).

(* 7) Weather resistance: 1200 for sunshine weatherometer
After the time test, the coated plate was washed with water, and the gloss retention (%) at 60 ° gloss was evaluated as follows.

Evaluation ◎: 81% or more ○: 70 to less than 81% (* 8) Acid resistance: The coated plate with the sealed enclosure is immersed in a 40% sulfuric acid aqueous solution at 30 ° C for 5 hours, then taken out and the state of the coating film is observed. did.

Evaluation ⊚: None above ○: A little dull in the immersed part (* 9) Storage stability of diluted paint: The viscous paint was placed in a closed glass bottle and the change in viscosity after storage at 50 ° C for 1 week was examined.

Evaluation: Viscosity change less than 3 seconds O: Viscosity change 3 seconds to 10 seconds x: Gelation

Claims (1)

(57) [Claims] 1. Polymer particles obtained by dispersing and polymerizing a monomer in the presence of a dispersion stabilizer resin, which is a high molecular weight polymer, are dissolved in an organic liquid which is insoluble. In the method for producing a dispersion liquid of polymer particles obtained by dispersion polymerization of a monomer, the dispersion stabilizer resin is represented by at least one polymerizable unsaturated group and at least one of the following formulas in one molecule. , A siloxy group bonded to a carbon atom However, R ₁ , R ₂ : C _{1 to} C ₁₈ alkyl group, phenyl group, allyl group, Cl, H, FR ₃ : C _{1 to} C ₁₈ alkyl group, phenyl group, allyl group 5 to 60% by weight of the saturated monomer (A),
Number average molecular weight 1, which is obtained by copolymerizing the monomer (A) with 95-40% by weight of a polymerizable unsaturated monomer (B)
A siloxy group-containing copolymer of 000 to 35,000 and / or a modified product obtained by introducing a radical-polymerizable unsaturated double bond into the copolymer is used, and the monomer to be dispersion-polymerized is one kind. Alternatively, a method for producing a dispersion liquid of polymer particles, which is characterized by comprising two or more kinds of ethylenically unsaturated monomers.