JPH0564162B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a method for producing a non-aqueous resin dispersion liquid useful for paints, adhesives, toners of electrophotographic liquid developers, and the like. Prior art A polyhydric alcohol diacrylate such as diethylene glycol dimethacrylate and a polymerizable monomer such as lauryl acrylate are mixed in toluene,
In aromatic hydrocarbon solvents such as benzene and xylene,
A method of producing a copolymer resin by carrying out a polymerization reaction in the presence of a polymerization initiator is known. Resins obtained in this way have been widely used for paints and adhesives. However, since aromatic hydrocarbon solvents are used in these resin (solution) 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. Similarly, when this non-aqueous resin is used for paints or adhesives, 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 acrylic 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. Purpose The present invention uses an aliphatic solvent that has almost no toxicity and flammability, has low solubility in the resulting resin, and is photochemically inactive, thereby eliminating rapid crosslinking reactions during polymerization and improving the polymerization process. A method for producing a non-aqueous resin dispersion that facilitates control of the process, has excellent storage stability, has no decrease in adhesive strength, has fewer problems in terms of environmental hygiene, and has less risk of fire. The goal is to provide the following. Structure The method for producing a non-aqueous resin dispersion according to the present invention is to produce a non-aqueous resin dispersion using the general formula (However, R is hydrogen or a methyl group, n is an integer from 1 to 20) and a monomer represented by the general formula {However, R' is hydrogen or methyl group, A is -
COOC _o ′H _2o ′ ₊₁ or −OCOC _o ′H _2o ′ ₊₁ (n′ is 6 to
(an integer of 20)} is characterized by polymerization reaction in the presence or absence of a polar monomer and/or other reactive monomer. In the polymerization reaction of the present invention, the nonaqueous solvent is generally heated to reflux, and the monomer represented by the above general formula (hereinafter referred to as monomer A), the monomer represented by the above general formula (hereinafter referred to as monomer B), and a polymerization initiator. This is carried out by dropping a mixed monomer solution containing . In this polymerization reaction, monomer A, i.e., polyfunctional acrylate or methacrylate, has a reactive polyfunctional group in its molecule, so it easily copolymerizes with other polymerizable monomers, giving the resulting resin a crosslinked structure. On the other hand, since monomer B is solvated in the non-aqueous solvent even after polymerization, it imparts solubility to the resin and, as a result, particularly contributes to the dispersion stability of the resin. Here, the ratio of monomer A and monomer B is 1:
Approximately 1 to 99 (weight) is appropriate. Moreover, polar monomers and other reactive monomers can be added and copolymerized to these monomers A and B as other polymerizable monomers (hereinafter referred to as monomer C), if necessary. Further, in the above polymerization reaction, fine silica particles, wax or polyolefin having a softening point of about 60 to 130°C can be added. When fine silica particles are used, it is thought that the resin is obtained with the fine silica particles incorporated into its crosslinked 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, dispersion stability can be further improved by having a specific gravity similar to that of an aliphatic hydrocarbon as a 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. considered to be a thing. Here, wax or polyethylene has a specific gravity similar to that of the dispersion medium, prevents the resin from gelling, 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 amount of silica, wax, or polyolefin added is 5 to 5 parts by weight per 100 parts by weight of the resulting resin.
Approximately 50 parts by weight is appropriate. Next, the materials used in the present invention will be explained. First, specific examples of polyfunctional (meth)acrylates of the general formula will be shown.

[Table] All of the compounds having the above general formulas can be easily produced according to methods described in known production methods, and can also be easily obtained as commercial products. Monomer B has the general formula [Here, R' is hydrogen or methyl group, A is -
COOC _o ′CH _2o ′ ₊₁ or −OCOC _o ′H _2o ′ ₊₁ (where n′ is an integer from 6 to 20), respectively. ] Specific examples of the monomers are 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. Next, among monomers C, specific examples of polar monomers include unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, unsaturated nitrogen-containing compounds, glycidyl group-containing unsaturated compounds, and alkyl acrylates (with 1 to 1 carbon atoms).
5) Examples include esters and/or alkyl methacrylates (having 1 to 5 carbon atoms). Here, unsaturated carboxylic acids and their anhydrides include acrylic acid, methacrylic acid, itaconic acid, fumaric acid,
Examples include 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, etc. are exemplified, and further examples of alkyl (carbon number 1 to 5) esters of acrylic acid or methacrylic acid include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, and propyl methacrylate. , butyl acrylate, butyl methacrylate and the like. Further, typical examples of the unsaturated compound containing a glycidyl group include glycidyl acrylate and glycidyl methacrylate. Among monomers C, other reactive monomers include styrene, vinyltoluene, vinyl acetate, polyhydric alcohol dimethacrylate (e.g. ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol methacrylate, triethylene glycol triacrylate,
Triethylene glycol trimethacrylate, butanediol diacrylate, butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tetramethylolmethane triacrylate acrylate,
Tetramethylolmethane trimethacrylate, tetramethylolmethanetetraacrylate, tetramethylolmethanetetramethacrylate, dipropylene glycol diacrylate, dipropylene glycol dimethacrylate, trimethylolhexane triacrylate, trimethylolhexane trimethacrylate, pentaerythritate tetraacrylate, pentaerythritol Examples include lithotetramethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, trimethylolethane triacrylate, trimethylolethane methacrylate), and the like. As a polymerization initiator, 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. Polyethylene example

【table】

【table】

[Table] Next, petroleum-based aliphatic hydrocarbons or halogenated aliphatic hydrocarbons are used as the non-aqueous solvent. Specifically, 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, K;
Naphtha No. 6 and Ciel Sol manufactured by Ciel Sekiyu Co., Ltd.), carbon tetrachloride, perfluoroethylene, etc. 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 characteristic that gelation or solidification of the resin is difficult to occur during the polymerization reaction or during storage. These petroleum-based aliphatic hydrocarbons or halogenated aliphatic hydrocarbons have high insulation properties (electrical resistance of 10 ^{to 10} Ω・cm
above), it is a solvent with a low dielectric constant (dielectric constant of 3 or less).
Further, aromatic solvents such as benzene and toluene may be added to these aliphatic solvents in small amounts. Examples are shown below. Example 1 2.0 equipped with stirrer, thermometer and reflux condenser
Take 300g of isooctane in a four-necked flask,
Heated to 95°C. A solution consisting of 190 g of dodecyl methacrylate, 10 g of the above-mentioned No. 1 compound, and 6 g of azobisisobutyronitrile was added dropwise to this solution over a period of 3 hours, and the mixture was further stirred at the above temperature for 4 hours to carry out a polymerization reaction. A resin dispersion with a viscosity of 240 cp was obtained at a yield of 96.2%. The particle size of the resin is 0.20~
It was 0.30μ. Example 2 300 g of the resin dispersion obtained in Example 1 was mixed with 10 g of colloidal silica in a flask, heated at 100°C for 3 hours, and then cooled to a viscosity of 300 cp and a particle size.
A resin dispersion containing colloidal silica of 0.30-0.60μ was obtained. Example 3 300 g of isododecane in the same flask as in Example 1.
was taken and heated to 90°C. Next, add 300g of lauryl methacrylate, 5g of N-vinylpyridine,
25g of the compound No. 5 above and 3g of benzoyl peroxide
After dropwise adding the solution consisting of
A resin dispersion with a viscosity of 530 cp and a particle size of 0.15 to 0.33 μm was obtained at 93.0%. Example 4 300 g of the resin dispersion obtained in Example 3 was mixed with 20 g of exposed beeswax in a flask, stirred at 95°C for 22 hours, and then cooled to a viscosity of 660 cp and a particle size of 0.30 to 0.89 μ.
A beeswax-containing resin dispersion was obtained. Example 5 300g of Isopar G in the same flask as Example 1
and 30g of colloidal silica were taken and heated to 90°C. In this, 2-ethylhexyl methacrylate
150g, glycidyl methacrylate 15g, the above No.
After dropping a solution consisting of 20 g of the compound No. 8, 40 g of methyl methacrylate, and 6.3 g of lauroyl peroxide, the polymerization reaction was carried out by further stirring at the above temperature for 4 hours, resulting in a polymerization rate of 92.0%, a viscosity of 326 cp, and a particle size.
A resin dispersion of 0.38-0.66μ was obtained. Example 6 300g of Isopar L in the same flask as Example 1
and polyethylene (AC- manufactured by Allied Chemical Company)
6) Add 60g and heat to 95°C. Next, a solution consisting of 180 g of stearyl methacrylate, 40 g of lauryl methacrylate, 3 g of fumaric acid, 20 g of the compound No. 15 above, and 4 g of lauryl peroxide was added dropwise into the solution over a period of 3 hours, and the mixture was further heated for 3 hours at the above temperature.
A polymerization reaction was carried out by stirring for hours to obtain a resin dispersion with a polymerization rate of 95.4%, a viscosity of 380 cp, and a particle size of 0.20 to 0.60 μm. Example 7 In the same flask as Example 1, 300 g of Isopar H,
Cetyl methacrylate 180g, dodecyl acrylate 40g, compound No. 12 above 15g, acrylic acid 5
g and 3 g of benzoyl peroxide were taken and stirred at 90° C. for 6 hours to carry out a polymerization reaction to obtain a resin dispersion having a polymerization rate of 96.0%, a viscosity of 55.5 cp, and a particle size of 0.20 to 0.60 μm. Examples 8 to 15 Table 2 was prepared in the same manner as in Example 7 except that the materials shown in Table 1 below and the reaction conditions shown in Table 2 below were used.
A resin dispersion having the properties shown below was prepared.

【table】

[Table] Example 16 In the same reactor as Example 1, 300 g of isooctane,
Take 100 g of lauryl methacrylate, 50 g of the compound No. 7 above, and 5 g of benzoyl peroxide, heat polymerize at 90°C for 10 hours, and then add to this polymer 50 g of 2-ethylhexyl methacrylate, 10 g of glycidyl methacrylate, and 1 g of benzoyl peroxide. Add the solution and heat at the above temperature for 2 hours.
The mixture was added dropwise over a period of time and then stirred at this temperature for 3 hours to carry out a further polymerization reaction to obtain a resin dispersion with a polymerization rate of 93.8%, a viscosity of 260 cp, and a particle size of 0.30 to 0.60 μm. Example 17 The same method as in Example 16 was used except that 2-ethylhexyl methacrylate was used instead of lauryl methacrylate and methacrylic acid was used instead of glycidyl methacrylate, with a viscosity of 650 cp and a particle size of 0.30 to
A 0.90μ resin dispersion was obtained. The polymerization rate is 98.5%
It was hot. Effects As described above, since the method of the present invention uses an aliphatic solvent as a reaction solvent, rapid crosslinking during polymerization is eliminated, making it easier to control the polymerization process, and also improving storage stability and improving adhesive strength. In addition, the working environment is improved and the risk of fire is reduced.

Claims (1)

[Scope of Claims] 1. In the presence of a polymerization initiator in a non-aqueous solvent mainly composed of aliphatic hydrocarbons, the general formula (However, R is hydrogen or a methyl group, n is an integer from 1 to 20) and a monomer represented by the general formula {However, R' is hydrogen or methyl group, A is -
COOC _o ′H _2o ′ ₊₁ or −OCOC _o ′H _2o ′ ₊₁ (n′ is 6 to
20 (an integer of 20)} A method for producing a non-aqueous resin dispersion, which comprises polymerizing a monomer represented by the following formula in the presence or absence of a polar monomer and/or other reactive monomer.