JPH0334485B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a method for producing a non-aqueous resin dispersion useful for paints, adhesives, electrophotographic liquid developer toners, and the like. Prior art A polyfunctional (meth)acrylic ester such as diethylene glycol dimethacrylate and a polymerizable monomer such as lauryl acrylate are polymerized in an aromatic hydrocarbon solvent such as toluene, benzene, or xylene in the presence of a polymerization initiator. A method of producing a copolymer resin dispersion by reaction is known.
The resins obtained in this way have been widely used for paints and adhesives. However, since aromatic hydrocarbon solvents are used in these resin dispersion manufacturing methods, crosslinking of the resin tends to proceed, resulting in problems such as gelation of the resin during the polymerization reaction and solidification of the resin during storage. It was hot. The same applies when this non-aqueous resin is used for paints or adhesives, and the adhesive strength decreases due to solidification during storage. In order to solve these problems, it has conventionally been necessary to suppress the amount of polyfunctional (meth)acrylic acid ester such as polyvalent glycol diacrylate to 3% by weight or less. Furthermore, even if the above problems are solved in this way, the resin is soluble in aromatic solvents and is therefore obtained in a dissolved state, so if it is used as is in a paint, the adsorption of the resin to the pigment may occur. Since the amount is small and the adhesive strength is insufficient, it is undesirable especially when used in electrodeposition coatings. Furthermore, the aromatic solvent used in this method is highly toxic and flammable, which not only poses problems in terms of environmental health, but also poses a risk of fire. Therefore, the present inventors proposed a method for producing a non-aqueous resin dispersion that eliminates the above-mentioned problems in Japanese Patent Application Laid-Open No. 56-79112.
proposed in the issue. This method involves combining a polyfunctional (meth)acrylic acid ester such as the one described above and an unsaturated carboxylic acid in the presence of a polymerization initiator in a solvent mainly composed of an aliphatic hydrocarbon or a halogenated aliphatic hydrocarbon. In this method, a polar monomer and a monomer, such as lauryl acrylate, which can be solvated with the solvent both before and after polymerization are subjected to a polymerization reaction. However, in this method, the crosslinking agent, polyfunctional (meth)acrylic acid ester, has high crosslinking properties, that is, the crosslinking speed is fast. (2) Because polymerization is not uniform, only a product with a wide particle size distribution can be obtained; (3) The dispersion stability of the product is poor. In addition, polyfunctional (meth)acrylic acid Since the monomer does not have a polar group, (4)
It also has the disadvantage that it has a low ability to disperse colorants, and even if a polar monomer is used in combination, copolymerization is poor and uniform polymerization cannot be achieved. Purpose The first object of the present invention is that by using a crosslinking agent that has a polar group and has appropriate crosslinking properties, it is possible to obtain products with little variation, excellent dispersion stability, and various particle size distributions. Another object of the present invention is to provide a method for producing a non-aqueous resin dispersion that has good dispersibility with respect to a colorant and can undergo a uniform polymerization reaction with other monomers during polymerization. The second object of the present invention is to have low toxicity and flammability.
By using an aliphatic solvent that has low solubility in the resulting resin and is photochemically inert,
It is an object of the present invention to provide a method for producing a non-aqueous resin dispersion that has excellent storage stability, does not cause a decrease in adhesive strength, has few problems in terms of environmental hygiene, and has little risk of fire. Structure The method for producing the non-aqueous resin dispersion of the present invention is to produce a non-aqueous resin dispersion of the general formula (However, R is -H or -CH ₃ group, X is halogen, n
represents an integer from 1 to 20. ) A general formula that can be solvated with the monomer A represented by the above solvent both before and after polymerization

[Formula] (However, R ₁ is -H or -CH ₃ group, A is -COOC _n
H _2n+1 or -OCOC _n H _2n+1 , m represents an integer from 6 to 20. ) It is characterized by causing a polymerization reaction with monomer B shown in the following. This polymerization reaction is carried out while heating the solvent to reflux. Through this reaction, a copolymer resin having a three-dimensional structure in which the monomer components are moderately crosslinked with each other in the form of a network is obtained. Here, monomer A is a crosslinking agent with a polar group, which is made of a polyfunctional halogenated (meth)acrylic acid ester, and has the property of being solvated with an aliphatic solvent before polymerization, but not solvating after polymerization. When the resin obtained by the method of the present invention is used in paints and the like, it controls the charge polarity of the resin and contributes to the dispersion stability of the colorant.
Furthermore, since monomer B is solvated in the solvent even after polymerization, the resin has excellent dispersion stability. The weight ratio of monomer A:monomer B is 0.1 to 20:
Approximately 1 to 50 is appropriate. Furthermore, in order to further improve charge polarity and dispersibility for colorants, a polar monomer (hereinafter referred to as monomer C) and other monomers are mixed to the same weight as monomer B as polymerizable monomers other than the above monomer components, and polymerized. It is also possible. Further, in the present invention, fine silica particles, wax or polyolefin having a softening point of about 60 to 130°C can be added to the resin manufacturing process. When fine silica particles are used, it is thought that the resin is obtained with the fine silica particles incorporated in its network structure.
In this case, the silica itself does not undergo physical changes such as dissolution during the reaction. In any case, in the case of silica, the dispersion stability can be further improved by making the specific gravity similar to that of the aliphatic hydrocarbon or its halide as the dispersion medium and by preventing gelation of the resin. On the other hand, when wax or polyolefin is used, these are dissolved in the reaction system by heating during the polymerization reaction, but after the reaction, they are precipitated into fine particles by cooling, and the resin is obtained in a state that is adsorbed to these fine particles. it is conceivable that. Here, wax or polyolefin has a specific gravity similar to that of the dispersion medium, prevents gelation of the resin, and has a molecular structure similar to that of the dispersion medium, so it not only helps improve dispersion stability, but also has a low softening point. It also helps improve adhesion. The appropriate amount of silica, wax or polyolefin added is about 5 to 50 parts by weight per 100 parts by weight of the resin. Next, the materials used in the present invention will be explained. The petroleum aliphatic hydrocarbons or halogenated aliphatic hydrocarbons used in the present invention include ligroin, n-hexane, n-pentane, n-heptane, n-octane, i-octane, i-dodecane, i- Nonane (commercially available products include Exxon's Isopar H, G, L, and K; Naphtha No. 6 and Shell Oil Co., Ltd.'s Ciel Sol), carbon tetrachloride, perfluoroethylene, and the like. These aliphatic hydrocarbons or halogenated aliphatic hydrocarbons have a higher flash point than aromatic solvents such as benzene and toluene, and are also less toxic. Since the solubility of the resin of the present invention is lower than that of aromatic solvents, it also has the advantage that the resin is unlikely to gel or solidify during the polymerization reaction or during storage. These petroleum-based aliphatic hydrocarbons or halogenated aliphatic hydrocarbons are solvents with high insulating properties (electrical resistance of 10 ¹⁰ Ω·cm or more) and low dielectric constants (dielectric constant of 3 or less). Further, aromatic solvents such as benzene and toluene may be added to these aliphatic solvents in small amounts. Monomer A is generally produced by an esterification reaction between glycidyl methacrylate and methacrylic acid. Representative examples of monomer A include the following. Monomer B has the general formula

[Formula] (However, R ₁ is -H or -CH ₃ group, A is -COOC _n
H _2n+1 or -OCOC _n H _2n+1 , m represents an integer from 6 to 20. ) Specific examples thereof include lauryl methacrylate, lauryl acrylate, stearyl methacrylate, stearyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, dodecyl methacrylate, dodecyl acrylate, hexyl methacrylate, hexyl acrylate, and octyl acrylate. , octyl methacrylate, cetyl methacrylate, cetyl acrylate, vinyl laurate, vinyl stearate, etc. Monomer C includes unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, unsaturated nitrogen-containing compounds, glycidyl group-containing unsaturated compounds, alkyl acrylates (1 to 5 carbon atoms) esters, and/or alkyl methacrylates (1 to 5 carbon atoms). ~5) There are esters, etc. Here, unsaturated carboxylic acids and their anhydrides include acrylic acid, methacrylic acid, itacone,
Examples include fumaric acid, maleic acid, crotonic acid, aconitic acid, cinnamic acid, and anhydrides thereof.
Examples of unsaturated nitrogen-containing compounds include vinylpyrrolidone, 2-vinylpyridine, 4-vinylpyridine, N-vinylpyridine, N-vinylimidazole, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, and acrylic Examples of the alkyl ester (having 1 to 5 carbon atoms) of acid or methacrylic acid include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, and butyl methacrylate. Further, typical examples of the unsaturated compound containing a glycidyl group include glycidyl acrylate and glycidyl methacrylate. Other polymerizable monomers include styrene, vinyltoluene, vinyl acetate, and the like. The polymerization initiators used when polymerizing these monomers A, B, C, etc. include benzoyl peroxide, t-butyl perbenzoate, diamyl peroxide, di-t-butyl peroxide,
Lauryl peroxide and azobisisobutyronitrile can be used. Further, specific examples of commercially available waxes or polyolefins having a softening point of 60 to 130°C are as follows.

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[Table] Effects By using monomer A as described above having a polar group as a crosslinking agent in the production of non-aqueous resin dispersions, dispersion resin products with less variation, excellent dispersion stability, and various particle size distributions can be produced. In addition, it has good dispersibility with respect to colorants, and can perform a uniform polymerization reaction with other monomers during polymerization. Furthermore, since an aliphatic solvent is used as the reaction solvent, environmental hygiene problems caused by aromatic solvents are also solved. Examples Examples of the present invention are shown below. Example 1 300 g of Isopar G was placed in a second flask equipped with a stirrer, a thermometer, and a reflux condenser, and heated to 90°C. Then, in a nitrogen stream, a solution consisting of 170 g of lauryl methacrylate, 30 g of compound No. (1), and 3 g of benzoyl peroxide was added dropwise over 2 hours to cause a polymerization reaction, and then at 95°C to complete the reaction. After stirring for 2 hours, a resin dispersion with a polymerization rate of 95.8% and a viscosity of 260 cp was obtained. The particle size of this resin was 3 to 4 microns. Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that diethylene glycol dimethacrylate was used instead of compound No. (1) to obtain a resin dispersion. The polymerization rate of this product was 95.8%, the viscosity was 290 cp, and the particle size of the resin was 5 to 9 μm. Comparative Example 2 In Example 1, instead of 30 g of compound No. (1), 30 g of polyethylene glycol dimethacrylate was used.
Polymerization was carried out in the same manner except that a mixture of 10 g and 10 g of methacrylic acid was used to obtain a resin dispersion. The polymerization rate of this product was 96.0%, the viscosity was 435 cp, and the particle size of the resin was 4 to 7 μm. Next, a colorant dispersion stability evaluation test was conducted on the resin dispersions obtained in Example 1 and Comparative Examples 1 and 2. 15 g of carbon black was dispersed in 100 g of the resin dispersion, diluted with 100 g of Isopar H, and further dispersed in a ball mill for 48 hours. Pour this colorant dispersion into a sedimentation tube with a diameter of 10 mm and a height of 300 mm.
After being left at ℃ for 30 days, the height of the supernatant liquid, that is, the distance from the liquid surface to the colored surface was measured.

[Table] From the above results, it is clear that the resin dispersion of the present invention has high dispersion stability with respect to colorants. Example 2 250 g of the resin dispersion obtained in Example 1 was added to 20 g of polyethylene (DYNF manufactured by Union Carbide).
After heating and dissolving at 110° C. for 3 hours, the mixture was cooled to obtain a polyethylene-containing resin dispersion having a viscosity of 100 cp. The particle size of this resin was 0.5 to 2μ. Example 3 300 g of isooctane was placed in the same container as in Example 1 and heated to 90°C. Next, add 170 g of cetyl methacrylate, 20 g of compound No. (2), 10 g of N-vinylpyridine and 5 g of azobisisobutyronitrile.
The above solution was added dropwise over 1 hour to cause a polymerization reaction, and the reaction was completed by further heating at 95°C for 3 hours. In this way, a resin dispersion with a polymerization rate of 96.5% and a viscosity of 60 cp was obtained. The particle size of this resin was 1-1.5 microns. Example 4 250 g of the resin dispersion obtained in Example 3 was mixed with 18 g of bleached beeswax in a flask, heated and stirred at 100°C for 2 hours, and then cooled to form a resin dispersion containing bleached beeswax with a viscosity of 200 cp. Prepared. The particle size of this resin was 0.3 to 0.5μ. Example 5 In the same container as in Example 1, 300 g of isooctane and 10 g of silica powder with a particle size of 1 to 2 μm were placed and heated to 95°C. A solution consisting of 150 g of 2-ethylhexyl methacrylate, 15 g of compound No. (4), 28 g of glycidyl methacrylate, 25 g of styrene and 5 g of azobisisobutyronitrile was added dropwise to this solution over 2 hours to cause a polymerization reaction, and then further The reaction was completed by stirring at 95°C for 2 hours. In this way, a resin dispersion with a polymerization rate of 98.2% and a viscosity of 156 cp was obtained.
The particle size of this resin was 2 to 5 microns. Example 6 Isopar L300 was added to the same flask as in Example 1.
g and polyethylene (AC-405) 30g, 95
heated to ℃. Next, in this, 150 g of stearin methacrylate, 21 g of compound No. (5), and 10 g of itaconic acid.
A solution consisting of 5 g, 30 g of methyl methacrylate, and 5 g of lauryl peroxide was added dropwise at the above temperature for 1 hour to cause a polymerization reaction, and then the reaction was completed by further heating at the same temperature for 3 hours. In this way, a resin dispersion with a polymerization rate of 96% and a viscosity of 120 cp was obtained. The particle size of this resin was 0.5-2μ.

Claims (1)

[Claims] 1. In a non-aqueous solvent containing an aliphatic hydrocarbon or a halogenated aliphatic hydrocarbon as a main component, in the presence of a polymerization initiator, the general formula (However, R is -H or -CH ₃ group, X is halogen, n
represents an integer from 1 to 20. ) A general formula that can be solvated with the monomer A represented by the above solvent both before and after polymerization [Formula] (However, R ₁ is -H or -CH ₃ group, A is -COOC _n
H _2n+1 or -OCOC _n H _2n+1 , m represents an integer from 6 to 20. ) A method for producing a non-aqueous resin dispersion, characterized by carrying out a polymerization reaction with monomer B represented by: