JPH0368883B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for stably producing an aqueous resin dispersion having excellent mechanical suitability and coating workability by a multi-stage emulsion polymerization method. It has been known to produce aqueous resin dispersions by multi-stage emulsion polymerization for the purpose of achieving high solidity differentiation, improving fluidity, controlling particle size and particle size distribution, and improving various properties of dried films. . However, when trying to produce large particles with excellent mechanical suitability and coating workability, large diameter, and narrow particle size distribution using conventional methods, the aqueous resin dispersion used as a seed in the first stage is added in the second stage. There was a problem in that it absorbs α,β-ethylenically unsaturated monomers, becomes swollen, tends to aggregate, and is difficult to industrially mass-produce in a stable state. One way to stabilize this is to use a large amount of emulsifier, but
This method has the disadvantage that the particle size cannot be increased and the water resistance of the film deteriorates, so that the original purpose cannot be fully achieved. As a result of intensive research in order to improve the above-mentioned problems, the present inventors have discovered that a polyvalent vinyl compound and/or a polyvalent allyl compound and an α,β-ethylenically unsaturated monomer having a sulfonic acid substituent , a water-soluble α,β-ethylenically unsaturated monomer and other α,
When an aqueous resin dispersion obtained by adding it to the main component consisting of β-ethylenically unsaturated monomer and emulsion polymerization is used as a seed, the aqueous resin dispersion has a large particle size and a narrow particle size distribution. The present invention was completed based on the discovery that the present invention can be obtained. That is, the present invention comprises 1 to 10% by weight of a water-soluble α,β-ethylenically unsaturated monomer (A), a polyvalent vinyl compound and/or a polyvalent allyl compound.
(B) 0.1 to 5% by weight, α,β-ethylenically unsaturated monomer having a sulfonic acid substituent (C) 0.1 to 3% by weight, and other copolymerizable α,β-ethylenically unsaturated monomers Monomer (D) 82 to 98.8% by weight is emulsion polymerized in water in the presence of a radical-generating catalyst, and using the resulting aqueous resin dispersion as a seed, α,β-ethylenically unsaturated monomer is further emulsion polymerized. The present invention provides a method for producing an aqueous resin dispersion characterized in that it increases the amount of water. The water-soluble α,β-ethylenically unsaturated monomer (A) used in the present invention is a monomer that is itself water-soluble and whose homopolymer is water-soluble. . Among them, preferable ones include, for example,
Examples include (meth)acrylic acid, dimethylaminomethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and (meth)acrylamide. Examples of the polyvalent vinyl compound and/or polyvalent allyl compound (B) include divinyl compounds and trimethacrylate compounds,
Examples of polyvalent allyl compounds include diallyl compounds and triallyl compounds. Among these, preferred examples include divinylbenzene, ethylene glycol dimethacrylate, 1,3-butylene dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and diallyl phthalate. Examples of the α,β-ethylenically unsaturated monomer (C) having a sulfonic acid substituent include vinyl aromatic sulfonic acids such as vinylbenzenesulfonic acid, vinylsulfonic acid, 2-sulfoethyl (meth)acrylate,
Examples include sulfoalkyl esters of α-methylenecarboxylic acid such as 2-sulfopropyl (meth)acrylate, and ammonium salts or metal salts thereof. Also included are sulfonic acids containing an allyl group or metaallyl group represented by the following general formula (1) or (2), and ammonium salts or metal salts thereof. (In the formula, R ₁ is hydrogen or a methyl group, R ₂ is an alkyl group, cycloalkyl group, oxyalkyl group, A is an alkylene group having 2 to 4 carbon atoms, n is O or a positive integer, M ₁ is an alkali metal or alkaline earth metals,
Ammonium, organic amine base or organic quaternary ammonium base. ) Specific examples of compounds represented by general formulas (1) and (2) include, for example: etc. Other copolymerizable α,β-ethylenically unsaturated monomers (D) include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2 - Alkyl esters of (meth)acrylic acid such as ethylhexyl (meth)acrylate, preferably alkyl esters having 1 to 8 carbon atoms, vinyl such as vinyl acetate, vinyl propionate, vinyl versatate (tertiary carboxylic acid), etc. Examples include esters, nitrogen-containing vinyl compounds such as acrylonitrile and N-vinylpyrrolidone, and aromatic unsaturated monomers such as styrene, α-styrene and vinyltoluene. The total amount of these monomers (A) to (D) to be used is
When 100% by weight, the water-soluble α,β-ethylenically unsaturated monomer (A) is usually 1 to 10% by weight, and the polyvalent vinyl compound and/or polyvalent allyl compound (B) is 0.1 to 10% by weight.
5% by weight, α,β-ethylenically unsaturated monomer (C) having a sulfonic acid substituent 0.1 to 3% by weight, other copolymerizable α,β-ethylenically unsaturated monomers
(D) The proportion is 82 to 98.8% by weight. When the amount of unsaturated monomer (A) used above is less than 1% by weight or more than 10% by weight, and when the amount of compound (B) or unsaturated monomer (C) used is less than 0.1% by weight, If the amount of the compound (B) exceeds 5% by weight or the unsaturated monomer (C) exceeds 3% by weight, stable production may not be possible due to the formation of aggregates. , it becomes difficult to obtain an aqueous resin dispersion with a large particle size and a narrow particle size distribution. In the first stage emulsion polymerization carried out in the present invention, known and commonly used chain transfer methods such as organic thiol compounds such as t-dodecyl mercaptan and lauryl mercaptan, and organic halogen compounds such as chloroform and carbon tetrachloride may be used as necessary. The molecular weight can also be adjusted by using an anionic emulsifier such as sodium dodecylbenzenesulfonate, sulfate of alkaryl polyether; polyoxyethylene nonylphenol ether, polyoxyethylene- Nonionic emulsifiers such as polypropylene block copolymers; cationic emulsifiers such as laurylpyridinium chloride, cetyltrimethylammonium bromide, etc. can also be used, but it is of course possible to conduct the process without using any of the known and commonly used emulsifiers as mentioned above. can. Radical generating catalysts commonly used in emulsion polymerization include hydrogen peroxide, ammonium persulfate,
Known and commonly used polymerization initiators such as potassium persulfate, t-butyl hydroperoxide, etc. can be used, and furthermore, such polymerization initiators are used in the form of a redox initiator in combination with a known reducing substance such as ascorbic acid or sulfite. I can also do things. or,
The polymerization temperature is preferably in the range of 30 to 90°C, and the resin solid content is preferably in the range of 3 to 70% by weight, preferably 5 to 50% by weight. In addition, it is preferable that the conversion rate of unsaturated monomers in the first stage emulsion polymerization is high, but if the conversion rate is 60% by weight or more, unreacted unsaturated monomers (A) to (D) is consumed in the second and subsequent reactions, so it does not pose a particular problem. The pH of the seed aqueous resin dispersion obtained by the reaction as described above is adjusted as desired, and subsequent polymerization reactions are carried out in the second and subsequent stages.Of course, the dispersion that is taken out after cooling is used. You may do so.
At that time, the amount of the aqueous resin dispersion used as the seed is 2
Usually 0.2 to 30 parts by weight of other α,β-ethylenically unsaturated monomers polymerized in the subsequent stages.
Parts by weight (solid weight). Other α,β-ethylenically unsaturated monomers and radical generation catalysts used in the second and subsequent stages include unsaturated monomers (A) used in producing the seed aqueous resin dispersion.
Although any of (D) can be used, it is preferable to use as little unsaturated monomer (C) as possible in order to narrow the particle size distribution. Further, the above-mentioned known and commonly used chain transfer agents can also be used for the purpose of adjusting the molecular weight, if necessary. As for the emulsifier, all known and commonly used emulsifiers that can be used when producing the aqueous resin dispersion that is the seed can be used, but of course it is also possible to use no emulsifier at all. For the purpose of obtaining a product with a narrow distribution, it is preferable to polymerize the emulsifier in a small amount or in the absence of the emulsifier in the second and subsequent reactions. The other α,β-ethylenically unsaturated monomers to be reacted in the second and subsequent stages may be added dropwise continuously or may be added in multiple stages. The reaction temperature in the second and subsequent stages is preferably in the range of 30 to 90°C, and the solid content of the finally obtained synthetic resin aqueous dispersion is preferably 30 to 65% by weight. The aqueous synthetic resin dispersion thus obtained can be used as it is as a main ingredient for textile processing, paints, adhesives, etc., but if necessary, known and commonly used stabilizers, thickeners, pigments, and fillers may be added. Appropriate amounts of additives, plasticizers, wetting agents, antifoaming agents, etc. may be added. The present invention will be specifically explained below by giving Examples and Comparative Examples. In addition, parts and percentages in the examples are based on weight unless otherwise specified. Example 1 1400 parts of deionized water and 1.5 parts of polyoxyethylene nonylphenol ether were added to a reaction vessel equipped with a stirrer, a condenser, a thermometer, and a dropping funnel, and the internal temperature was raised to 80°C while stirring. Furthermore, after introducing nitrogen gas into the container, 1 part of acrylic acid, 0.5 part of acrylamide, and divinylbenzene were added.
0.5 parts of sodium styrene sulfonate, 15 parts of styrene, 82.5 parts of ethyl acrylate, and 2 parts of ammonium persulfate. Then at the same temperature 1
The first stage reaction was completed by holding for a certain time. The polymerization conversion rate was 92%. Then 25% ammonia water 5
After injecting a mixture of 30 parts of acrylic acid, 300 parts of styrene, 670 parts of ethyl acrylate, 0.5 parts of t-dodecyl mercaptan, and a mixture of 3 parts of ammonium persulfate and 100 parts of deionized water at the same temperature, each The mixture was injected over 3 hours, kept at the same temperature for 1 hour, and then cooled to obtain the desired aqueous resin dispersion. Resin solid content is 40.8%, viscosity is
It was 150cps. Comparative Example 1 The first stage reaction was completed in the same manner as in Example 1, except that the addition of divinylbenzene and sodium styrene sulfonate was omitted and the amount of ethyl acrylate added was changed to 83.5 parts. The polymerization conversion rate was 95%. Next, a second stage reaction was carried out in the same manner as in Example 1 to obtain an aqueous resin dispersion for comparison. The resin solid content was 39.4% and the viscosity was 140 cps. Example 2 In a reaction vessel similar to Example 1, add 1470 ml of deionized water.
1 part, and 2 parts of polyoxyethylene nonylphenol ether were added, and the internal temperature was raised to 80°C while stirring. Furthermore, after introducing nitrogen gas into the container, 2 parts of methacrylic acid, 1 part of acrylamide, 1 part of diallyl phthalate, chemical formula

2 parts of the compound represented by the formula, 10 parts of methyl methacrylate, 20 parts of methyl acrylate, 64 parts of ethyl acrylate, and 2 parts of ammonium persulfate were charged. Thereafter, the same temperature was maintained for 1 hour to complete the first stage reaction. The polymerization conversion rate was 95%. Next, after injecting 5 parts of 25% ammonia water, 30 parts of methacrylic acid, 100 parts of methyl methacrylate, 200 parts of methyl acrylate, and 670 parts of ethyl acrylate were added at the same temperature.
0.5 parts of t-dodecyl mercaptan and a mixture of 3 parts of ammonium persulfate and 100 parts of deionized water were each divided into 6 parts, each 1 part was added in multiple stages every 30 minutes, and the entire amount was added. The mixture was further maintained at the same temperature for 1 hour and then cooled to obtain the desired aqueous resin dispersion. Resin solid content is 41.9
%, and the viscosity was 120 cps. Comparative Example 2 Diaryl phthalate and chemical formula

The first stage reaction was completed in the same manner as in Example 2, except that the addition of the compound represented by the formula was omitted and the amount of ethyl acrylate added was changed to 67 parts. Polymerization conversion rate is 90
It was %. Next, the second and subsequent reactions were carried out in the same manner as in Example 2 to obtain an aqueous resin dispersion for comparison. The resin solid content was 40.3% and the viscosity was 120 cps. Comparative Example 3 The first stage reaction was completed in the same manner as in Example 2, except that the addition of diacrylphthalate was omitted and the amount of ethyl acrylate added was changed to 65 parts. The polymerization conversion rate was 93%. Next, the second and subsequent reactions were carried out in the same manner as in Example 2 to obtain an aqueous resin dispersion for comparison. The resin solid content was 41.3% and the viscosity was 150 cps. Comparative example 4 Chemical formula

The first stage reaction was completed in the same manner as in Example 2, except that the addition of the compound represented by the formula was omitted and the amount of ethyl acrylate added was changed to 66 parts. The polymerization conversion rate was 90%. Next, the second and subsequent reactions were carried out in the same manner as in Example 2 to obtain an aqueous resin dispersion for comparison. Resin solid content is 41.0%, viscosity is
It was 120cps. Comparative Example 5 Addition amount of diallyl phthalate is 6 parts, chemical formula

The first stage reaction was completed in the same manner as in Example 2, except that the amount of the compound represented by the formula was changed to 5 parts and the amount of ethyl acrylate added was changed to 56 parts. Polymerization conversion rate is 93%
It was hot. Next, the second and subsequent reactions were carried out in the same manner as in Example 2 to obtain an aqueous resin dispersion for comparison. The resin solid content was 41.9% and the viscosity was 1000 cps. Example 3 In a reaction vessel similar to Example 1, add 1370 ml of deionized water.
1 part, 5 parts of 5% FeCl ₃ 6H ₂ O aqueous solution, and 2 parts of sodium pyrosulfite were added, and the internal temperature was brought to 60°C while stirring.
The temperature was raised to ℃. Furthermore, after introducing nitrogen gas into the container, 2 parts of methacrylic acid, 1 part of acrylamide,
1 part diallyl phthalate, chemical formula

2 parts of the compound represented by the formula, 10 parts of methyl methacrylate, 20 parts of methyl acrylate, 64 parts of ethyl acrylate
1 part, and 2 parts of ammonium persulfate.
Thereafter, the same temperature was maintained for 1 hour to complete the first stage reaction. The polymerization conversion rate was 91%. Then 25%
After pouring 5 parts of ammonia water, 30 parts of methacrylic acid, 100 parts of methyl methacrylate, 200 parts of methyl acrylate, 670 parts of ethyl acrylate at the same temperature.
part, a mixture of 0.5 parts of t-dodecyl mercaptan,
A mixture of 3 parts ammonium persulfate and 100 parts deionized water and a mixture of 3 parts sodium pyrosulfite and 100 parts deionized water were each injected over a period of approximately 3 hours and held at the same temperature for an additional hour. The desired aqueous resin dispersion was obtained by cooling. The resin solid content was 40.8% and the viscosity was 150 cps. Example 4 In a reaction vessel similar to Example 1, add 1400 ml of deionized water.
After adding 2 parts of polyoxyethylene nonylphenol ether and raising the internal temperature to 80℃ while stirring and introducing nitrogen gas into the container, 7 parts of methacrylic acid, 4 parts of divinylbenzene, and styrene sulfonate were added. 1 part of acid soda, 35 parts of styrene, 47.5 parts of ethyl acrylate, and 2 parts of ammonium persulfate were charged. Thereafter, the same temperature was maintained for 1 hour to complete the first stage reaction. The polymerization conversion rate at that time was 96%. Next, after injecting 5 parts of 25% ammonia water, at the same temperature, a mixture of 30 parts of acrylic acid, 300 parts of styrene, 670 parts of ethyl acrylate, and a mixture of 3 parts of ammonium persulfate and 100 parts of deionized water were injected. The mixture was injected over a period of time, kept at the same temperature for 1 hour, and then cooled to obtain an aqueous resin dispersion. The resin solid content was 40.5% and the viscosity was 130 cps. The amount of aggregates produced and the particle size (average particle size, coefficient of variation of particle size) of the aqueous resin dispersions obtained in Examples 1 to 3 and Comparative Examples 1 to 5 were measured. The results are shown in Table-1. Incidentally, the measurements were carried out as follows. (1) Measurement of the amount of aggregates produced: The aggregates in the aqueous resin dispersion are sieved through a 200-mesh wire mesh, dried, and the ratio to the gold solid weight is calculated. (2) Measurement of particle size: Measured using a transmission electron microscope "JEM-30 30B Super Scope" manufactured by JEOL Ltd. In addition, the coefficient of variation of particle size =
Standard deviation of particle diameter/average particle diameter.

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Claims (1)

[Claims] 1. Water-soluble α,β-ethylenically unsaturated monomer (A)
1 to 10% by weight, polyvalent vinyl compound and/or polyvalent allyl compound
(B) 0.1 to 5% by weight, α,β-ethylenically unsaturated monomer having a sulfonic acid substituent (C) 0.1 to 3% by weight, and other copolymerizable α,β-ethylenically unsaturated monomers Emulsion polymerization of 82 to 98.8% by weight of monomer (D) in water in the presence of a radical-generating catalyst, using the resulting aqueous resin dispersion as a seed, further emulsion polymerization of α,β-ethylenically unsaturated monomer 1. A method for producing an aqueous resin dispersion, the method comprising: