JP3763853B2 - Method for producing microgel - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for producing a microgel useful for printing ink, paint, adhesive, toner for electrophotographic liquid developer, and the like.
[0002]
[Prior art]
Conventionally, as prior arts of microgels, JP-A-55-71713, JP-A-54-78791, JP-A-52-117951 and the like are known. By the way, a polyhydric alcohol diacrylate such as diethylene glycol dimethacrylate and a polymerizable monomer such as lauryl acrylate are subjected to a polymerization reaction in the presence of a polymerization initiator in an aromatic hydrocarbon solvent such as toluene, benzene, and xylene. Methods for producing polymer resins are known. The resin thus obtained has been widely used for paints and adhesives. However, since an aromatic hydrocarbon solvent is used in such a method for producing a resin (solution), crosslinking of the resin is likely to proceed, causing problems such as the resin becoming a macrogel during the polymerization reaction and the resin solidifying during storage. was there. The same applies to the case of using this non-aqueous resin for paints and adhesives, and the adhesive strength is reduced by solidification during storage. Therefore, in order to solve these problems, conventionally, it has been necessary to suppress the amount of polyfunctional acrylic ester such as polyvalent glycol diacrylate to 3% by weight or less. Even if the above problems are solved in this way, the resin is soluble in an aromatic solvent and cannot obtain a microgel, and thus can be obtained in a dissolved state. Is undesired particularly when used in electrodeposition paints because it has a low adsorbing power of the resin to the pigment and lacks adhesion.
[0003]
Furthermore, the aromatic solvent used in this method is not only toxic and flammable, but has a problem of not only environmental hygiene but also a high risk of fire.
[0004]
In general, microgels are conventionally produced by emulsion polymerization or suspension polymerization. For example, there are Shinsuke Yamazaki et al., 25, 86 (1987), Takeyasu Yamamoto et al., 5th Polymer Microsphere Discussion (1988) P56. Although this method can obtain a polymer having a fine particle diameter, an emulsifier and a dispersant remain in the coating film, and there is a problem in moisture absorption resistance. On the other hand, there are few known methods for producing non-aqueous microgels. Tsufuko et al. 46, no. 11, P 723-731 (Nov. 1989), there is a drawback that the particle size distribution is wide.
[0005]
[Problems to be solved by the invention]
The object of the present invention is to use a non-aqueous solvent that has low toxicity and low flammability, low solubility in the resulting resin, and is photochemically inactive. It is to provide a method for producing a non-aqueous microgel resin dispersion with less problems in terms of environmental sanitation and less risk of fire, and to provide a method for producing a non-aqueous microgel having a uniform particle size. Another object of the present invention is to provide a method for producing a microgel useful as an electrophotographic toner.
[0006]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found that the problem can be solved by copolymerization with a specific combination of monomers in a non-aqueous solvent, and have reached the present invention.
[0007]
That is, the present invention provides a polyfunctional vinyl monomer and at least one monomer A represented by the following general formula ( 3) or (4) in the presence of a polymerization initiator in a non-aqueous solvent selected from silicone oil and vegetable oil. at least one monomer B chosen over or al, is a manufacturing how microgels, which comprises polymerizing at least containing the monomer mixture and the other polymerizable monomer C (although ethylene is not included).
[0008]
General formula (3)
R ₁ CH = CHCOOR ₂
(In the formula, R ₁ represents H or C _n H _{2n + 1} (n = 1 to 20), R ₂ represents C _m H _{2m + 1} (m = 1 to 20))
General formula (4)
CH ₂ = C (R) COO (CH ₂ ) _n X
(In the formula, R represents H or CH ₃ , n represents 1 to 20, and X represents halogen)
[0011]
As the monomer A represented by the general formula (3) used in the present invention, for example,
No. 1 CH ₃ —CH═CHCOOCH ₃ ,
No. _{2 CH 3 -CH = CHCOOC 2 H} 5,
No. 3 CH ₃ —CH═CHCOOC ₄ H ₉ ,
No. 4 CH ₃ —CH═CHCOOC ₁₀ H ₂₁ ,
No. 5 CH ₃ —CH═CHCOOC ₁₂ H ₂₅ ,
No. 6 CH ₃ —CH═CHCOOC ₁₆ H ₃₃ ,
No. 7 CH ₂ = CHCOOCH ₃ ,
No. 8 CH ₂ = CHCOOC ₅ H ₁₁ ,
No. 10 CH ₂ = CHCOOC ₂₀ H ₄₁ ,
No. 11 C ₁₂ H ₂₅ CH═CHCOOCH ₃ ,
No. _{12 C 18 H 37 CH = CHCOOC} 2 H 5,
No. 13 C ₃ H ₇ CH═CHCOOC ₁₂ H ₂₅ ,
Etc.
[0012]
As the monomer A represented by the general formula (4) used in the present invention, for example,
No. 1 CH ₂ = CHCOOCH ₂ CH ₂ Br,
No. 2 CH ₂ = CHCOOCH ₂ CH ₂ I,
No. 3 CH ₂ = CHCOOCH ₂ CH ₂ Cl,
No. 4 CH ₂ = CHCOOCH ₂ CH ₂ CH ₂ Br,
No. 5 CH ₂ ═C (CH ₃ ) COOCH ₂ CH ₂ I,
No. 6 CH ₂ ═C (CH ₃ ) COOCH ₂ Br,
No. 7 CH ₂ ═C (CH ₃ ) COO (CH ₂ ) ₅ Br,
No. 8 CH ₂ ═C (CH ₃ ) COO (CH ₂ ) ₁₂ Cl,
No. _{9 CH 2 = CHCOO (CH 2} ) 18 Br,
No. 10 CH ₂ = CHCOO (CH ₂ ) ₂₀ I,
Etc.
[0014]
The polyfunctional vinyl monomer B used in the present invention includes dimethacrylate (for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol methacrylate, triethylene glycol triacrylate, triethylene glycol trimethacrylate, butane. Diol diacrylate, butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tetramethylolmethane triacrylate, tetramethylolmethane trimethacrylate , Tetramethylol methane tetraacrylate, tetramethyl Methane tetramethacrylate, dipropylene glycol diacrylate, dipropylene glycol dimethacrylate, trimethylol hexane triacrylate, trimethylol hexane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, 1,3-butylene glycol diacrylate 1,3-butylene glycol dimethacrylate, trimethylol ethane triacrylate, trimethylol ethane methacrylate), divinylbenzene and the like.
[0018]
In addition, when the monomer A of the general formula (3) is used, it is 30 to 95% by weight with respect to the total monomers, and when the monomer A of the general formula (4) is used, it is 50 to 90% by weight. B can be copolymerized at 0.1 to 30% by weight. The monomer A component of the general formulas (3) and (4) contributes to the charging, dispersion, and adhesiveness of the microgel, and the effect is reduced when it is less than 30 wt% and 50 wt%, respectively. On the other hand, if it exceeds 95% by weight and 90% by weight, microgels are hardly formed. When these monomers are used, it is easier to produce a microgel than when a conventional (meth) acrylic acid ester monomer is used, and microparticles are produced with a uniform and small particle size.
[0019]
On the other hand, if the polyfunctional monomer is less than 0.1% by weight, it is difficult to form a microgel. When it exceeds 30% by weight, it becomes macrogel.
[0021]
The pigments present in the polymerization system in the present invention are carbon black, oil blue, alkali blue, phthalocyanine blue, phthalocyanine green, spirit black, aniline black, oil violet, benzidine yellow, methyl orange, brilliant carmine, first red, crystal violet. And dyes or pigments such as triiron tetroxide, nigrosine, titanium oxide, and zinc oxide. These pigments are preferably present at 5 to 50% by weight with respect to the monomer mixture.
[0022]
In the present invention, other polymerizable monomer C, silica fine particles, wax or polyolefin having a softening point of about 60 to 130 ° C. can be added to the resin production process. When silica fine particles are used, the resin is considered to be obtained in a state in which the silica fine particles are incorporated in the network structure. In this case, the silica itself is not affected by physical changes such as dissolution during the reaction as well as the silica itself. In any case, in the case of silica, the dispersion stability can be further improved by making the specific gravity close to that of the dispersion medium and preventing the gelation of the resin. On the other hand, when wax or polyolefin is used, they are dissolved in the reaction system by heating during the polymerization reaction, but after the reaction, they are precipitated in the form of fine particles by cooling, so that the resin is obtained in a state of being adsorbed by these fine particles. It is considered a thing. Here, wax or polyethylene has a specific gravity similar to that of the dispersion medium and prevents gelation of the resin, and the molecular structure is similar to that of the dispersion medium, so it not only helps to improve dispersion stability but also has a low softening point. Also useful for improving adhesion. The addition amount of silica, wax or polyolefin is suitably about 1 to 50 parts by weight per 100 parts by weight of the resin.
[0023]
Next, the material used in the present invention will be described.
[0024]
In the present invention, other monomers can be copolymerized as necessary. Such other polymerizable monomers C include polar monomers and other reactive monomers, and the polar monomers include unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, unsaturated nitrogen-containing compounds, glycidyl group-containing unsaturated compounds. And alkyl acrylate (carbon number 1 to 5) ester and / or alkyl methacrylate (carbon number 1 to 5) ester. Here, examples of the unsaturated carboxylic acid and its anhydride include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, crotonic acid, aconitic acid, cinnamic acid, and anhydrides thereof. Examples of unsaturated nitrogen-containing compounds include vinyl pyrrolidone, 2-vinyl pyridine, 4-vinyl pyridine, N-vinyl pyridine, N-vinyl imidazole, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate and the like. Examples of the alkyl (1 to 5 carbon atoms) ester of acid or methacrylic acid include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate and the like. Furthermore, glycidyl acrylate and glycidyl methacrylate are typically exemplified as glycidyl group-containing unsaturated compounds.
[0025]
Examples of other polymerizable monomer C include styrene, vinyl toluene, and vinyl acetate.
[0026]
As polymerization initiators used for polymerizing monomers A, B, and C, benzoyl peroxide, t-butyl perbenzoate, diamyl peroxide, di-t-butyl peroxide, lauryl peroxide, azobis Isobutyronitrile can be used.
[0027]
Examples of the non-aqueous solvent used in the present invention include various silicone oils and vegetable oils.
[0045]
Example 17
In a 2.0 liter four- necked flask equipped with a stirrer, a thermometer and a reflux condenser, 300 g of silicone oil, KF58 (manufactured by Shin-Etsu Silicone) was taken and heated to 90 ° C. Next, the above general formula (3) No. A solution comprising 300 g of monomer A, 5 g of N-vinylpyridine, 25 g of ethylene glycol dimethacrylate and 3 g of benzoyl peroxide was added dropwise over 1.5 hours, followed by stirring at the above temperature for 4 hours to conduct a polymerization reaction. A microgel resin dispersion having a viscosity of 180 cp and a particle size of 0.4 to 0.15 μm was obtained at 98%. General formula (3) No. When lauryl methacrylate was used in place of the monomer No. 6, the particle size was 3-5 μm.
[0046]
Example 18
300 g of the microgel resin dispersion obtained in Example 17 was mixed with 20 g of bleached beeswax in a flask, stirred at 95 ° C. for 22 hours, cooled and exposed to a viscosity of 220 cp and a particle size of 0.6 to 0.7 μm. A beeswax-containing microgel resin dispersion was obtained.
[0047]
Example 19
In a 2.0 liter four- necked flask equipped with a stirrer, a thermometer and a reflux condenser, 300 g of sesame oil and 30 g of colloidal silica were taken and heated to 90 ° C. Among them, the general formula (3) No. No. 7 monomer A 150 g, glycidyl methacrylate 15 g, trimethylolpropane triacrylate 20 g, methyl methacrylate 40 g and lauroyl peroxide 6.3 g were added dropwise, and further stirred for 4 hours at the above temperature to conduct a polymerization reaction. A microgel resin dispersion having a viscosity of 140 cp and a particle size of 0.5 to 0.6 at a rate of 98% was obtained.
[0052]
Example 24
In a 2.0 liter four- necked flask equipped with a stirrer, a thermometer and a reflux condenser, 300 g of silicone oil, KF96, 2.0 (manufactured by Shin-Etsu Silicone) was taken and heated to 90 ° C. Next, the above general formula (4) No. No. 9 monomer A 300 g, N-vinylpyridine 5 g, ethylene glycol dimethacrylate 25 g, and a solution of 3 g of benzoyl peroxide were added dropwise over 1.5 hours, followed by stirring at the above temperature for 4 hours to conduct a polymerization reaction, and the polymerization rate A microgel resin dispersion having a viscosity of 580 cp and a particle size of 2 to 3 μm was obtained at 98%.
[0053]
Example 25
300 g of the microgel resin dispersion obtained in Example 24 was mixed with 20 g of bleached beeswax in a flask, stirred at 95 ° C. for 22 hours, and then cooled to a viscosity of 600 cp, and a bead wax-containing microgel having a particle size of 3 to 4 μm. A resin dispersion was obtained.
[0054]
Example 26
In a 2.0 liter four- necked flask equipped with a stirrer, a thermometer and a reflux condenser, 300 g of corn oil and 30 g of colloidal silica were taken and heated to 90 ° C. Among them, the general formula (4) No. 10 g of monomer A 150 g, glycidyl methacrylate 15 g, diethylene glycol diacrylate 20 g, methyl methacrylate 40 g and lauroyl peroxide 6.3 g were added dropwise, and the mixture was further stirred for 4 hours at the above temperature to carry out a polymerization reaction. A microgel resin dispersion having a viscosity of 270 cp and a particle size of 0.05 to 0.07 μm was obtained.
[0085]
【The invention's effect】
As described above, according to the present invention, a microgel having a uniform particle size can be obtained.
[0086]
Further, the microgel obtained by polymerization in the presence of a pigment is useful as an electrophotographic toner.

Claims (4)

In the presence of a silicone oil, a polymerization initiator in a non-aqueous solvent selected from vegetable oils, selected at least one polyfunctional vinyl monomer over whether these monomers A represented by the following general formula (3) or (4) A method for producing a microgel comprising polymerizing a monomer mixture containing at least one monomer B and another polymerizable monomer C (but not including ethylene).
General formula (3)
R ₁ CH = CHCOOR ₂
(In the formula, R ₁ represents H or C _n H _{2n + 1} (n = 1 to 20), and R ₂ represents C _m H _{2m + 1} (m = 1 to 20)).
General formula (4)
_{CH 2 = C (R) COO} (CH 2) n X
(In the formula, R represents H or CH ₃ , n represents 1 to 20, and X represents halogen)   Furthermore, the manufacturing method of the microgel of Claim 1 superposed | polymerized in presence of a pigment.   Furthermore, the manufacturing method of the microgel of Claim 1 superposed | polymerized in presence of a wax or polyolefin wax.   Furthermore, the manufacturing method of the microgel of Claim 1 superposed | polymerized in presence of a metal salt and / or a basic substance.