JPH0433284B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing amphoteric polymer particles, and more particularly to a method for obtaining an amphoteric polymer having a low impurity content in the form of particles. (Prior art and problems to be solved by the invention) Conventionally, aqueous solution polymerization method or reverse phase suspension polymerization method is known as a method for obtaining amphoteric polymer particles, but in aqueous solution polymerization, the particle size during polymerization is Not only is it impossible to increase the monomer concentration because it becomes difficult to remove the heat of polymerization, but it also has the drawback that drying and pulverization are difficult. Particulate polymers can also be obtained by so-called reverse-phase suspension polymerization, in which polymerization is performed with an aqueous solution of a monomer mixture dispersed or suspended in a hydrophobic solvent. In order to obtain a pure polymer, it is unavoidable that post-treatment steps become complicated because of the use of agents.
Furthermore, in order to obtain a polymer in particulate form, a special drying method is required, such as removing water from the polymer by azeotropic dehydration. Furthermore, if monomer remains in the polymer particles, it is not easy to remove the residual monomer in any polymerization method. The object of the present invention is to provide a method for producing amphoteric polymer particles which does not have the above-mentioned drawbacks. (Means for Solving the Problems) The object of the present invention is to contain an ethylenically unsaturated amine monomer 1, an ethylenically unsaturated carboxylic acid monomer 2, and a nonionic ethylenically unsaturated amide monomer 3. Using a radical polymerization initiator, the monomer mixture is
When polymerizing without using a dispersant in a lower alcohol that dissolves each monomer, the total amount of monomer 2 and monomer 3 in the monomer mixture is monomer 1,
This is achieved by using a method for producing amphoteric polymer particles characterized in that the amount of monomer 2 and monomer 3 is at least 30 mol % of the total amount. The feature of the present invention is that when obtaining hydrophilic polymer particles, a monomer mixture is polymerized without using a dispersant such as an oil-soluble surfactant, and the polymer is produced in the form of fine particles. Since almost no unreacted monomer remains in the polymerization method, there is an advantage that the process is extremely simplified compared to conventionally known polymerization methods. The ethylenically unsaturated amine monomer 1 used in the present invention has the general formula (In the formula, R ₁ is H or a methyl group, R ₂ is a C ₁ to C ₁₂ alkylene group, R ₃ and R ₄ are H or a C ₁ to C _{12 alkyl group, and A is a C 1 to C 12} alkyl group.

【formula】

It is a monomer represented by [Formula] or -O-), such as methylaminoethyl (meth)acrylate, t
- amino acids of ethylenically unsaturated carboxylic acids such as butylaminoethyl (meth)acrylate, dimethyl-aminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dibutylaminoethyl (meth)acrylate, etc. Alkyl esters; aminoalkylamides of ethylenically unsaturated carboxylic acids such as methylaminoethyl (meth)acrylamide, dimethylaminoethyl (meth)acrylamide, dimethylaminopropyl (meth)acrylamide; aminoethyl vinyl ether,
Examples include aminoalkyl vinyl ethers such as methylaminoethyl vinyl ether and dimethylaminoethyl vinyl ether. Furthermore, quaternized versions of these amine monomers can also be used. These monomers may be used alone or in combination. The ethylenically unsaturated carboxylic acid monomer 2 used in the present invention includes acrylic acid, methacrylic acid,
Crotonic acid, cinnamic acid, itaconic acid, fumaric acid,
Unsaturated carboxylic acids such as maleic acid, butenetricarboxylic acid, 3-butenoic acid, and 4-pentenoic acid; monoalkyl unsaturated dicarboxylic acids such as itaconic acid monoethyl ester, fumaric acid monobutyl ester, and maleic acid monobutyl ester Examples include esters, which may be used alone or in combination of two or more. These monomers may be used as alkali metal salts such as Na salts and K salts, or as ammonium salts. Examples of the nonionic ethylenically unsaturated amide monomer 3 used in the present invention include acrylamide, methacrylamide, diacetone acrylamide, N
-Hydroxymethylacrylamide and the like, these monomers may be used alone or in combination of two or more, but acrylamide is particularly preferred. In the present invention, it is necessary that the total amount of monomers 2 and 3 in the mixture of monomers 1, 2, and 3 is 30 mol% or more. is not obtained. Preferably 50 mol%
That's all. The amounts of Monomer 1 and Monomer 2 to be used are appropriately determined depending on the intended use of the amphoteric polymer, and the amounts used are not particularly limited in the present invention. Usually the ratio of monomer 1 to monomer 2 is 20 to 80 mol%80 to 80
It is 20 mol%. Furthermore, in the present invention, in addition to monomers 1 to 3, monomers copolymerizable with these monomers can be used within the range where the polymer can be obtained in the form of particles. In order to obtain an amphoteric polymer in the form of particles by polymerization, it is essential to meet the requirements for the monomers described above and to use a lower alcohol capable of dissolving each of the monomers as a polymerization solvent. Examples of lower alcohols used in the present invention include methyl alcohol, ethyl alcohol, and propyl alcohol. Amphoteric polymer particles can be prepared by dissolving a monomer mixture in a lower alcohol to a concentration of 5 to 50% by weight, preferably 10 to 40% by weight, and polymerizing the mixture using a radical polymerization initiator. Manufactured. Another feature of the present invention is that there is no need to use a dispersant during polymerization. As the radical polymerization initiator used in the present invention, conventionally known azo compounds, organic peroxides, etc. are used. For example, as an azo compound, 2,2'-
Examples of the organic peroxide include azobissuine butyronitrile and 2,2'-azobis(2-methyl-valeronitrile), and examples of the organic peroxide include acetyl peroxide, propionyl peroxide, and isobutyryl peroxide. You can, but
These may be used in appropriate combinations, as long as they are soluble in the solvent used at the polymerization temperature. The amount used is not particularly limited, and varies depending on the type of the initiator, but is usually used in a proportion of 0.005 to 5 parts by weight per 100 parts by weight of the monomer mixture. Further, the polymerization temperature varies depending on the type of solvent and the type of radical initiator used, but it is usually desirable to be in the range of 20 to 100°C. After the polymerization is completed, the amphoteric polymer in the form of particles or powder is separated from the solvent by filtration or decantation. By drying the obtained polymer particles, they become extremely pure polymer particles with almost no unreacted monomer present. The amphoteric polymer of the present invention is a water-soluble polymer if no crosslinking monomer is present in the monomers used,
It can be used as a surfactant, dispersant, oil recovery aid, fiber, paper processing agent, etc. Also,
In the monomer mixture, e.g. methylenebis(meth)
Acrylamide, ethylene glycol di(meth)
When a crosslinking monomer such as acrylate or trimethylolpropane trimethacrylate is present, the polymer becomes water-insoluble and can be used as a water-absorbing polymer. (Example) The present invention will be specifically described below with reference to Examples. Example 1 A 200 ml reactor equipped with a stirring blade, a cooling condenser, a nitrogen gas inlet tube, and a thermometer was sufficiently purged with nitrogen in advance. Separately prepared dimethylaminopropylacrylamide (abbreviated as DMAPAA), methacrylic acid (abbreviated as MAA), and acrylamide (abbreviated as AAM) of polymerization g shown in Table 1 were dissolved in ethyl alcohol, and the total weight was 99 g. Pour the solution into the reactor, then add 1 part of ethyl alcohol.
0.05 g of azobisisobutyronitrile was dissolved in the solution and added to the stirring reactor. The reactor was immersed in a constant temperature bath at 60°C, and polymerization was carried out for 6 hours. After polymerization, the polymer was precipitated and separated into an ethyl alcohol supernatant phase and polymer particles by decantation. The polymer particles were dried under reduced pressure at 60°C. The morphology of the polymer is
Also listed in the table.

[Table] Example 2 Dimethylaminoethyl methacrylate (DM), acrylic acid (AA), and acrylamide (AAM) were copolymerized using the same recipe as in Example 1, and the results shown in Table 2 were obtained.

[Table] Example 3 Into the same reactor as in Example 1, 14.73 g of dimethylaminoethyl methacrylate, 4.07 g of acrylic acid,
1.17 g of acrylamide and 0.09 g of methylenebisacrylamide dissolved in 79 g of ethyl alcohol were charged, and then 0.05 g of azobisisobutyronitrile was dissolved in 1 g of ethyl alcohol and added to the reactor while stirring. The reactor was immersed in a constant temperature bath at 60°C, and the polymerization reaction was carried out for 6 hours with stirring. After polymerization, the polymer was precipitated, the ethyl alcohol supernatant phase and the polymer particles were separated by decantation, and the polymer particles were dried under reduced pressure at 80°C. The obtained polymer was particulate and had high water absorption.

Claims (1)

[Claims] 1. Using a radical polymerization initiator, a monomer mixture containing 1 ethylenically unsaturated amine monomer, 2 ethylenically unsaturated carboxylic acid monomers, and 3 nonionic ethylenically unsaturated amide monomers, When polymerizing without using a dispersant in a lower alcohol that dissolves monomers, the total amount of monomer 2 and monomer 3 in the monomer mixture is equal to monomer 1 and monomer 2. and at least 30 mol% of the total amount of monomer 3.