JPH0155643B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing a binder resin used in toners for developing electrostatic images. The present invention relates to a method for producing group-containing vinyl polymers.

PRIOR ART Vinyl polymers containing hydrophilic groups such as hydroxyl groups and carboxyl groups, that is, hydrophilic group-containing vinyl polymers, are produced by various polymerization methods, but suspension polymerization is particularly advantageous compared to solution polymerization. This method is superior in that no solvent is used, in that the reaction is easier to control than in the bulk polymerization method, and in that the polymerized resin is easier to separate than in the emulsion polymerization method.

By the way, in the conventional suspension polymerization method, starch,
A monomer containing a polymerization initiator is added all at once to water in which a suspending agent such as gelatin, polyvinyl alcohol, or tricalcium phosphate is dissolved, and suspended in the form of oil droplets at a temperature at which the reaction does not proceed rapidly, so-called room temperature. After that, the temperature of the suspension was raised to the reaction temperature, and at the same temperature
The reaction is completed by keeping warm for 8 hours. When attempting to produce a hydrophilic group-containing vinyl polymer using this method, soon after the start of the reaction, the half-polymers that had been suspended in particulate form fuse with each other and grow into large lumps (hereinafter referred to as a glutinous phenomenon). As a result, the desired particulate polymer could not be obtained. The reason why hydrophilic group-containing vinyl monomers tend to become cake-like is that because the monomers are hydrophilic, the boundary between the oil layer (monomer) and the water layer is not clear, and as the reaction progresses, sticky particles form. It is thought that they come into contact and fuse together during stirring, forming a lump.

To solve this problem, a method is proposed in which a vinyl monomer containing a hydrophilic group is dropped into water that has been heated to a temperature at which the vinyl monomer can be polymerized (Japanese Patent Application Laid-Open No. 59-111).
-78202) is known. This method is suitable for obtaining a hydrophilic group-containing vinyl polymer without causing cake-like formation.

Problems to be Solved by the Invention However, even in the method disclosed in JP-A-59-78202, a portion of the vinyl monomer undergoes emulsion polymerization, causing damage to the inner wall of the reaction vessel, the stirring blade, and the stirring rod. Because it is easy to adhere and accumulate on the parts,
There is a problem that a cleaning process is required for each batch, which reduces work efficiency. In addition, the number of particles generated is several micrometers.
Because it contains m fine particles, even in the overstep process,
There are problems in that the fine particles flow out together with water in the early stages of the process, and that the cloth becomes clogged in the middle to late stages of the process, making it impossible to continue the process, resulting in a decrease in yield and work efficiency.

An object of the present invention is to provide a method for producing a hydrophilic group-containing vinyl polymer that can solve these problems and stably obtain a hydrophilic group-containing vinyl polymer in high yield.

Means and Effects for Solving the Problems The present invention involves adding dropwise a vinyl monomer containing a hydrophilic group-containing vinyl monomer into an aqueous medium heated to a temperature at which the vinyl monomer can be polymerized, and carrying out suspension polymerization. In the method for producing a hydrophilic group-containing vinyl polymer, a water-soluble polymerization inhibitor is added to the aqueous medium in advance at a concentration of 0.001 to 0.001 to 0.001 to 0.001 to 0.001 to 0.01 to 0.01 to the total vinyl monomer.
This invention relates to a method for producing a hydrophilic group-containing vinyl polymer characterized in that it dissolves at 1% by weight.

The vinyl monomer of the present invention consists of only a hydrophilic group-containing vinyl monomer or a mixture of a hydrophilic group-containing vinyl monomer and another vinyl monomer copolymerizable therewith. The present invention employs a suspension polymerization method in which the vinyl monomer is dropped into an aqueous medium heated to a polymerizable temperature, and by doing so, it is possible to prevent cake-like formation during polymerization. This method is particularly effective when a large amount of the hydrophilic group-containing vinyl monomer is used, particularly when the proportion of the hydrophilic group-containing vinyl monomer in the vinyl monomer of the present invention is 10% by weight or more.

The hydrophilic group-containing vinyl monomers include 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, 2-hydroxy-3-phenylpropyl methacrylate, hydroxybutyl methacrylate, half ester of glycidyl methacrylate and methacrylic acid or acrylic acid. compound, half ester of bisphenol type epoxy resin and methacrylic acid or acrylic acid, acrylic acid 2
-Hydroxyethyl, hydroxypropyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate, hydroxybutyl acrylate,
Hydroxy group-containing vinyl monomers such as half esters of glycidyl acrylate and methacrylic acid or acrylic acid, acrylic acid, methacrylic acid, maleic acid, fumaric acid, mesaconic acid, itaconic acid, citraconic acid, formula: (In the formula, R ₁ represents hydrogen or a methyl group, R ₂ represents an alkylene group having 1 to 10 carbon atoms, and R ₃ represents an alkylene group having 1 to 10 carbon atoms, an aromatic ring, or a derivative thereof. , n is an integer of 1 to 3), carboxyl group-containing vinyl monomers such as adducts of maleic acid, fumaric acid, itaconic acid, or citraconic acid with glycidyl acrylate, glycidyl methacrylate, or epoxy resin, and acetic acid. vinyl, acrylamide,
Although there are methacrylamide and the like, hydroxyl group-containing vinyl monomers and carboxyl group-containing vinyl monomers are mainly used.

Other vinyl monomers that can be copolymerized with the hydrophilic group-containing vinyl monomer include styrene, α-methylstyrene, p-methylstyrene, pt-butylstyrene, p-chlorostyrene, and other styrene derivatives, methyl methacrylate, and methacrylate. ethyl acid,
Propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, Butoxyethyl methacrylate, methoxydiethylene glycol methacrylate, ethoxydiethylene glycol methacrylate, methoxyethylene glycol methacrylate, butoxytriethylene glycol methacrylate, methoxydipropylene glycol methacrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol methacrylate, methacrylic acid Phenoxytetraethylene glycol, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyloxyethyl methacrylate, N-vinyl-2-pyrrolidone methacrylate,
glycidyl methacrylate, methacrylonitrile,
N-methylolmethacrylamide, diacetone acrylamide, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,
Pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, methoxyethyl acrylate, propoxyethyl acrylate, butoxyethyl acrylate, methoxy acrylate Diethylene glycol, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, butoxytriethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxytetraethylene glycol acrylate, acrylic acid Benzyl, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, N-vinyl-2-pyrrolidone acrylate, glycidyl acrylate, acrylonitrile,
Vinyl monomers having one vinyl group in each molecule such as N-methylolacrylamide and diacetone acrylamide, divinylbenzene, reaction products of glycol and methacrylic acid or acrylic acid, such as ethylene glycol dimethacrylate, 1,3 -butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate,
1,5-pentanediol methacrylate, 1,
6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tripropylene glycol dimethacrylate, hydroxypivalic acid neopentyl glycol ester dimethacrylate, trimethylolethane trimethacrylate, Trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythritate tetramethacrylate, trismethacryloxyethyl phosphate, bis(methacryloyloxyethyl)hydroxyethyl isocyanurate, tris(methacryloyloxyethyl)isocyanurate, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate,
1,5-pentanediol diacrylate, 1,
6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene diacrylate, hydroxypivalate neopentyl glycol diacrylate, trimethylolethane triacrylate, trimethylol propane triacrylate,
Two or more vinyl groups in one molecule, such as pentaerythritol triacrylate, pentaerythritate tetraacrylate, trisacryloxyethyl phosphate, bis(methacryloyloxyethyl)hydroxyethyl isocyanurate, tris(methacryloyloxyethyl)isocyanurate, etc. Examples include vinyl monomers having the following.

Among these, preferred vinyl monomers having one vinyl group in one molecule include styrene, styrene derivatives, methacrylic esters, acrylic esters, etc.
In particular, alkyl esters of methacrylic acid or acrylic acid having 1 to 5 carbon atoms in the alkyl group are preferred, and vinyl monomers having 2 or more vinyl groups in one molecule include divinylbenzene and 2 to 6 carbon atoms. Dimethacrylate and diacrylate of methylene glycol are preferred. These are used in an amount of 0 to 20% by weight based on the total vinyl monomers.

As a polymerization initiator, acetyl peroxide, decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4 peroxide
-dichlorobenzoyl, diisopropyl perdicarbonate, di-2-ethylhexyl perdicarbonate, acetylcyclohexane sulfonyl peroxide, tert-butyl peracetate, tert-butyl perisobutyrate, azobisisobutyronitrile, 2-ethylhexane peroxide Tert-butyl acid, tert-butyl perbenzoate, etc. can be used. These polymerization initiators are preferably used in an amount of 0.1 to 15% by weight based on the total amount of vinyl monomers. Moreover, it is preferable to use these by dissolving them in a vinyl monomer.

In the present invention, dispersants include gelatin, gum tragacanth, starch, methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, partially saponified polyvinyl alcohol, water-soluble polymeric substances such as polyacrylic acid, organic dispersants such as alginate, barium sulfate, Any conventionally known dispersants can be used, such as calcium sulfate, calcium carbonate, barium carbonate, magnesium carbonate, tricalcium phosphate, and sparingly soluble inorganic dispersants such as talc, pentonite, diatomaceous earth, and clay. The amount of organic dispersant is 1×10 ^-4 to 5% by weight, and the amount of inorganic dispersant is 0.01 to 5% by weight based on the total amount of vinyl monomer used.
Preferably it is used in an amount of 3% by weight.

In addition, as dispersion aids, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, alkyl sulfonates with SO ₃ Na directly bonded to the alkyl group, β-tetrahydronaphthalene sulfonates, and sodium N-isopropylcyclohexylamide sulfonates. Anionic surfactants such as amidosulfonic acid salts such as amide sulfonates and higher fatty acid salts such as sodium oleate can be used in combination with the above-mentioned dispersants. In particular, when an inorganic dispersant is used as a dispersant, it is preferable to use a dispersion aid together. The dispersion aid is preferably used in an amount of 1.times.10.sup. ^-4 to 0.01% by weight based on the total amount of vinyl monomers used.

In the present invention, the water-soluble polymerization inhibitor includes:
Examples include sodium nitrite, potassium nitrite, cupric chloride, etc., but sodium nitrite is particularly preferred from the viewpoint of effectiveness. The amount of polymerization inhibitor added is 0.001 to 1% by weight, preferably 0.001 to 0.5% by weight, particularly preferably 0.005 to 1% by weight based on the total vinyl monomer.
It is 0.05% by weight. The amount added is 0.001% by weight
If it is less than that, emulsion polymerization cannot be prevented, and the amount of adhesion to the reaction container increases or fine particles are generated. When it exceeds 1% by weight, it tends to become cake-like during polymerization. In addition, when the amount of polymerization inhibitor increases, the particle size of the polymer particles increases, which not only makes it difficult to stir, but also makes it inconvenient to handle when making toner. The content is preferably 0.5% by weight or less.
The polymerization inhibitor is preferably dissolved in an aqueous medium in advance.

In the present invention, water is mainly used as the aqueous medium. A dispersant and, if necessary, a dispersion aid are added to this medium in advance.

In the present invention, the vinyl monomer is added dropwise to an aqueous medium, but at this time the aqueous medium is already heated to a temperature at which the vinyl monomer can polymerize. Here, the polymerizable temperature is equal to or higher than the decomposition start temperature of the polymerization initiator used. This temperature varies depending on the polymerization initiator used, but for example, benzoyl peroxide, tert-2-ethylhexanoate,
When butyl or the like is used, the temperature is 50°C or higher, and when diisopropyl perdicarbonate or di2-ethylhexyl perdicarbonate is used, the temperature is 30°C or higher. When the vinyl monomer is dropped into a medium that has not been heated to a temperature at which the vinyl monomer can be polymerized, caking occurs as in conventional methods. There are no particular restrictions on the total amount A of the vinyl monomer used and the amount B of the aqueous medium used, but if the A/B ratio is too large, suspension polymerization will not be able to be carried out smoothly. It is preferably 75/25 or less, particularly preferably 60/40 or less.

The vinyl monomer addition rate should be determined on average per 1 kg of vinyl monomer and aqueous medium used.
It is preferable to set it to 16.7 g/min or less. This addition rate (unit: g/min.Kg) is obtained by dividing the dropping rate of the vinyl monomer (unit: g/min) by the total amount of the vinyl monomer and water used (unit: kg). If the addition rate exceeds an average of 16.7g/min・Kg,
During polymerization, there is a tendency to form cakes. If the addition rate is too low, the polymerization time will become long, so it is preferably 1.38 g/min.Kg or more, particularly preferably 4 to 8.5 g/min.Kg. The addition rate is
Uniformity is preferred during the addition, but variations may be allowed. In this case, it is preferred that the addition rate does not exceed 16.7 g/min.Kg. This addition rate can be commonly applied even when the ratio of the aqueous medium to the vinyl monomer and the amounts used thereof are varied.

Examples Next, the present invention will be described in detail based on examples.
The present invention is not limited to this.

Example 1 Part by weight (1) Medium water 1000 Polyvinyl alcohol (Denka Poval W-
24, Denki Kagaku Kogyo Co., Ltd. trade name) 3 Nitrium nitrite 0.1 (0.01% by weight based on vinyl monomer) (2) Dropping liquid Styrene 500 n-butyl methacrylate 100 β-hydroxyethyl methacrylate 400 Benzoyl peroxide 30 Put the medium consisting of the composition of (1) above into a reaction container,
After raising the liquid temperature to 90°C, the dropping liquid having the composition (2) above was added dropwise at a uniform rate over a period of 1.5 hours, and the temperature was maintained at the same temperature for 4 hours. The amount of adhesion to the reaction vessel is
0.2% (based on total vinyl monomers), and the resulting polymer was granular with an average size of 1 mm. 200
Using mesh cloth, it can be filtered without clogging, and the polymer yield is 99%.
It was hot. The addition rate in this example is 5.6g/
It was hot in minutes/Kg. Incidentally, the dropping rate of the vinyl monomer was 11.1 g/min.

Example 2 Parts by weight (1) Medium water 1000 Polyvinyl alcohol (Gohsenol GH-
20, Nippon Gosei Kagaku Kogyo Co., Ltd. (trade name) 3 Sodium nitrite 0.3 (0.03% by weight based on vinyl monomer) (2) Dropping liquid Styrene 600 n-butyl acrylate 100 β-hydroxypropyl methacrylate 300 Peroxide Benzoyl 50 Put the medium consisting of the composition of (1) above into a reaction container,
After raising the liquid temperature to 90°C, the dropping liquid having the composition (2) above was added dropwise at a uniform rate over a period of 1 hour, and the temperature was maintained at the same temperature for 4 hours. The amount of adhesion to the reaction vessel is
0.1% (based on the total vinyl monomer), and the resulting polymer was granular with a diameter of about 1 mm.
Using a 200 mesh cloth, it can be passed through without clogging, and the yield of polymer is
It was 99%. The addition rate in this example is 8.3
g/min・Kg. Note that the vinyl monomer dropping rate was 16.7 g/min.

Example 3 Parts by weight (1) Medium Water 1200 Polyvinyl alcohol (Gohsenol GH-20
4 Sodium nitrite 0.5 (0.05% by weight based on vinyl monomer) (2) Dropped liquid Styrene 450 Ethyl methacrylate 100 n-butyl acrylate 100 β-hydroxypropyl methacrylate 150 Benzoyl peroxide 50 From the composition of (1) above Put the medium into the reaction vessel,
After raising the liquid temperature to 90°C, the dropping liquid having the composition (2) above was added dropwise at a uniform rate over 1 hour, and the temperature was maintained at the same temperature for 5 hours. The amount attached to the reaction vessel is 0.13
% (based on the total vinyl monomer), and the obtained polymer was granular with a diameter of about 1.5 mm. Using a 200 mesh cloth, it could be passed through without clogging, and the yield of the polymer was 99%. The addition rate in this example is 7.6 g/min.
It was Kg. In addition, the dropping speed of vinyl monomer is
It was 16.7 g/min.

Example 4 A hydrophilic group-containing vinyl polymer was produced in exactly the same manner as in Example 2 except that sodium nitrite was replaced with potassium nitrite. As a result, the amount of adhesion to the reaction vessel was
0.2%, and the resulting polymer was granular with an average size of 1 mm. Even when 200 mesh cloth was used, it could be passed through without clogging, and the yield was 99%.

Comparative Example 1 The reaction proceeded in exactly the same manner as in Example 1 except that sodium nitrite was removed. As a result, the amount of adhesion to the reaction vessel was 2.3% (based on the total vinyl monomer).
The obtained polymer was granular with an average particle size of 1 mm. Also, passing through a 200-mesh cloth caused clogging, and the cloth had to be changed three times to pass through all the polymer. The yield was 90%.

Effects of the Invention According to the present invention, a hydrophilic group-containing vinyl polymer can be produced with high working efficiency and high yield.

Claims (1)

[Scope of Claims] 1. A vinyl monomer containing a hydrophilic group-containing vinyl monomer is added dropwise to an aqueous medium heated to a temperature at which the vinyl monomer can be polymerized, and suspension polymerization is performed to produce a vinyl monomer containing a hydrophilic group. A method for producing a hydrophilic group-containing vinyl polymer, characterized in that a water-soluble polymerization inhibitor is previously dissolved in the aqueous medium in an amount of 0.001 to 1% by weight based on the total vinyl monomers. 2. The method for producing a hydrophilic group-containing vinyl polymer according to claim 1, wherein the water-soluble polymerization inhibitor is sodium nitrite, potassium nitrite, or cupric chloride. 3. A method for producing a hydrophilic group-containing vinyl polymer according to claim 1 or 2, wherein the vinyl monomer contains 10% by weight or more of a hydrophilic group-containing monomer. 4. The method for producing a hydrophilic group-containing vinyl polymer according to claim 1, 2 or 3, wherein the hydrophilic group-containing monomer is a hydroxyl group-containing vinyl monomer and/or a carboxyl group-containing vinyl monomer.