JPS59140202A - Production of spherical polymer particles - Google Patents

Abstract

PURPOSE:To produce spherical water-soluble particles of a large diameter stably by a simple and convenient method, by effecting the reversed phase suspension polymerization of a water-soluble ethylene monomer in the presence of a specified dispersant and a specified additive. CONSTITUTION:A copolymer obtained by graft-polymerizing methacrylic acid and an oil-soluble ethylenic monomer (e.g., ethyl methacrylate) with an ethylene- propylene-diene copolymer is used as a dispersant and a carboxyl group-free compound which is soluble in both aqueous and oil phases (e.g., acetone or methanol) is used as an additive. Namely, an aqueous solution of a water- soluble ethylenic monomer (e.g., a qauternary salt of dimethylaminoethyl methacrylate with methyl chloride) is polymerized in an organic medium immiscible with said solution (e.g., hexane) in the presence of the above dispersant and the additive to produce spherical polymer particles of a diameter of about 50- 1,000mu.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing water-soluble or water-swellable spherical polymers. More specifically, water-soluble polymers used in paper-making sizing agents, coating agents, textile glues, wastewater treatment agents, water-soluble thickeners, filter aids, and high-grade products used in sanitary products, agricultural water retention agents, etc. This invention relates to a method for producing an aqueous polymer in a spherical form without agglomerating or agglomerating it.

The most common method for polymerizing water-soluble ethylene monomers is aqueous solution polymerization, but other methods include precipitation polymerization, reverse-phase emulsion polymerization, and reverse-phase suspension polymerization. Among these methods, the reversed-phase suspension polymerization method is superior in that supermolecular weight polymers can be efficiently obtained in the form of spheres.

However, nonionic surfactants such as sorbitan fatty acid esters, which are generally known as dispersants for reverse-phase suspension polymerization, protective colloids such as cellulose derivatives, or
When polymerizing fine solid substances such as kaolin, the entire polymerization system sometimes becomes one lump, and even if the polymerization is successful, the resulting polymer is very fine.
The desired large particle size polymer cannot be obtained. Also, adhesion to the reaction tank is a drawback that cannot be overlooked from an industrial standpoint.

At least one macromolecule solvable in a liquid monomer phase and at least one macromolecule solvable in an organic medium as a dispersant as a method for preventing the formation of agglomerates and obtaining a polymer with a large particle size. A method of carrying out reverse-phase suspension polymerization using a macromolecular compound consisting of 50% is proposed (Japanese Patent Publication No. 55-8521).

However, even this method has drawbacks such as agglomeration of grains during polymerization, depending on the combination of the type of dispersant and the type of polymerization monomer, and is not fully satisfactory for industrial purposes.

The present inventors have developed a water-soluble polymer obtained by polymerizing a monomer mixture mainly composed of a water-soluble ethylene monomer by a stable and simple method without causing the above-mentioned disadvantages. As a result of intensive research to find a method for producing spherical particles with a large particle size, we have found that by carrying out polymerization in the presence of specific dispersants and additives, we can produce polymers with a large particle size without causing gelation of the particles. The present invention was completed based on the discovery that it is possible to produce the same.

That is, the present invention involves preparing a dissolved mixture of a water-soluble ethylene monomer and water in an organic medium that is substantially incompatible with the mixture, using an ethylene-propylene-diene monomer copolymer (hereinafter referred to as EPDM) as a dispersant. ) using a copolymer obtained by graft-polymerizing methacrylic acid and an oil-soluble ethylene monomer, and in the presence of a compound that is soluble in both oil and aqueous phases and does not contain carboxyl groups, reverse phase This is a method for producing a spherical polymer, which is characterized by polymerization using a suspension polymerization method.

In the method of the present invention, a graft copolymer obtained by graft-polymerizing methacrylic acid and an oil-soluble ethylene monomer to an ethylene-propylene-diene copolymer is used as the dispersant.

Such a graft copolymer is generally an ethylene-propylene-diene monomer copolymer (,
grpm), methacrylic acid, an oil-soluble ethylene monomer, and an oil-soluble radical initiator under stirring in a nitrogen atmosphere, preferably at a temperature of 40°C or higher and 100°C or lower. It is a water emulsion or solution.

When carrying out graft polymerization, it is essential that one component of the graft monomer is methacrylic acid, and this monomer makes it possible for the first time to produce a polymer having a large particle size with good dispersion. The oil-soluble ethylene monomers mentioned above include ethyl methacrylate, probyl methacrylate, butyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, methyl methacrylate, styrene, ethyl acrylate, and acrylic. Butyl acid, etc. can be used. In particular, ethyl methacrylate, propyl methacrylate, butyl methacrylate, etc. are preferably used.

The charging ratio of EPDM, methacrylic acid, and oil-soluble ethylene monomer is 100 parts by weight in total (EPi)
M80-901i parts, methacrylic acid 2-40 parts by weight,
The amount of oil-soluble ethylene monomer is preferably 2 to 40 parts by weight.

Examples of organic solvents that can dissolve EPDM include aliphatic hydrocarbons such as pentane, hexane, cyclohexane, heptane, and octane, and aromatic hydrocarbons such as benzene, toluene, and xylene.

The amount of dispersant used is generally 0.0% based on the monomer solution.
It is 5 to 4% by weight, preferably 0.1 to 2M%.

In the method of the present invention, the water-soluble ethylene monomers include dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dipropylaminoethyl methacrylate, dimethylamine propyl methacrylate,
In addition to salts in which amino groups such as diethylaminopropyl methacrylate, dipropylaminopropyl methacrylate, and vinyl pyridine are quaternized with alkyl halides such as methyl chloride, ethyl chloride, methyl chloride, and ethyl promite, and alkylating agents such as dimethyl sulfate, Examples include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid or their sodium or ammonium salts or acrylamide, and N-vinylpyrrolidone.

In particular, the method of the present invention is effective for copolymerizing a water-soluble ethylene monomer containing a quaternary amino group alone or a mixture with 70% by weight or less of another water-soluble ethylene monomer that can be copolymerized with it. It is.

In the present invention, organic media include aliphatic hydrocarbons such as butane, pentane, hexane, heptane, octane, and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, and chlorinated hydrocarbons such as chloroform, dichloromethane, ethyl chloride, and dichloroethane. Hydrogen etc. can be used.

The charging ratio of the water-soluble tyrenic monomer aqueous solution and the organic liquid is 40 to 6 parts by weight of the organic medium per 100 parts by weight of the monomer aqueous solution.
00 parts by weight is preferred.

In the present invention, it is highly soluble in both the aqueous phase and the oil phase.

As the compound that does not contain a carboxyl group, for example, ketones such as acetone and methyl ethyl ketone, and alcohols such as methanol and ethanol are preferably used. 50 parts by weight, preferably 8-80 parts by weight.

In the present invention, if polymerization is carried out in the absence of a compound that is soluble in both phases, a polymer that exhibits little dispersibility and becomes lumpy will be produced; however, if this compound is present in the coexistence, the polymer can be stably suspended in the reverse phase. Turbid polymerization progresses and a spherical polymer having a particle size of about 60-1000 microns can be obtained.

As the radical initiator, a water-soluble radical initiator such as potassium persulfate, ammonium persulfate, hydrogen peroxide, or a combination system of these with an appropriate reducing agent such as sodium bisulfite, sodium thiosulfite, sodium pyrosulfite, or Rongalit, etc. is used. Water-soluble azo initiators such as 2,2'-(azobis-2-amidi)pumpane dihydrochloride and azobiscyanopentanoic acid are preferably used.

The amount of initiator used is not particularly limited, but is preferably 0.005% by weight or more and 1M% or less based on the monomer.

According to the method of the present invention as detailed above, the polymer does not form lumps during polymerization, which causes operational difficulties, such as the inability to stir, leading to damage to the equipment, and adhesion to the reaction tank. It is possible to obtain a remarkable effect of avoiding such inconveniences.

Furthermore, since the spherical polymer produced by the method of the present invention has a large particle size, it has the great advantage that separation operations such as filtration are easy.

Hereinafter, the method of the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 (Synthesis of dispersant) No. 11 equipped with a stirring device, a Dimroth cooler, and a thermometer.
425 g of hexane in a separable flask, E P D
M (Product name manufactured by Sumitomo Chemical Co., Ltd.; Nisprene 80
1A) After charging 52.5F and dissolving it under reflux, add acid LL89.5F to methacrylic acid at room temperature. 11.8 grams of butyl methacrylate and 0.229 grams of azobisisobutyronitrile were added, and the temperature was raised to 66° C. under a nitrogen atmosphere, followed by reaction for 12 hours. The obtained dispersant was a white emulsion with a solid content concentration of 14.4% by weight.

(Production of spherical polymer) Quaternary salt 8 obtained by quaternizing dimethylaminoethyl methacrylate with methyl chloride in a separable flask equipped with a stirrer, a Dimroth condenser, a thermometer, and a dropping funnel.
07, water 40y1 acetone 7no, 2.2'-azobis-
0.14F of 2-amidinopropane hydrochloride, 50y1 of n-hexane, and 16F of the n-hexane solution of the dispersant synthesized above were charged. 25 Orpm after nitrogen replacement
The temperature was raised to 60° C. with stirring, and the temperature was kept at the same temperature for 2 hours, and then the temperature was raised to reflux temperature and azeotropic dehydration was performed for 2 hours to remove 35 g of water from the system.

This suspension was filtered through a glass filter to remove 10% of the polymer.
After washing with 0-n-hexane, it was dried in a ventilation dryer at 50° C. for 10 hours.

The obtained polymer is a spherical body with an average particle size of 850μ,
[η] −7,1(tN, N, r 8 in NO3 aqueous solution
0°C).

Comparative Example 1 An experiment similar to Example 1 was conducted except that acetone was not added. After 20 minutes of heating, the mixture became lumpy and no spherical particles were obtained.

Example 2 In a separable flask equipped with a stirrer, a Dimroth condenser, a thermometer, and a dropping CI-tube, 45 parts of quaternary salt obtained by quaternizing dimethylaminoethyl methacrylate with methyl chloride, 35 parts of acrylamide, and 46 parts of water were added. , ethanol 12P, 2.2'-azobis-2-amidinopro/man hydrochloride 0.141i', n-hexane 48y1, and 8 volumes of the dispersant solution synthesized above were charged, and the following operations were the same as in Example 1. Ta.

The obtained polymer was spherical with an average particle diameter of 250μ,
[η]=4.9.

Comparative Example 2 The same operation as in Example 2 was performed except that ethanol was not added. After 20 minutes of heating, the mixture became lumpy and no spherical particles were obtained.

Claims (3)

[Claims] (1) A dissolved mixture of water-soluble ethylene monomer and water,
In an organic medium that is substantially incompatible with the mixture, a graft copolymer obtained by graft-polymerizing methacrylic acid and an oil-soluble ethylene monomer to an ethylene-propylene-diene monomer copolymer is used as a dispersant, and 1. A method for producing a spherical polymer, which comprises polymerizing by a reversed-phase suspension polymerization method in the presence of a compound that is soluble in both a phase and an aqueous phase and does not contain a carboxyl group. (2) Claim 1, wherein the compound is soluble in both the oil phase and the water phase and does not contain a carboxyl group in an amount of 1 to 50 parts by weight based on 100 parts by weight of the water-soluble monomer. Method described. (3) The method according to claim 1, wherein the compound that is soluble in both the oil phase and the aqueous phase and does not contain a carboxyl group is a ketone or an alcohol.