JPH0413362B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a water-soluble spherical polymer. More details include paper sizing agents, coating agents, fiber sizing agents, wastewater treatment agents, water-soluble thickeners,
This invention relates to a method for producing water-soluble polymers used in spherical products without gelation. As a method for polymerizing a monomer mixture mainly consisting of a water-soluble ethylene monomer having a quaternary amino group,
Aqueous solution polymerization is the most common, but other methods such as precipitation polymerization, reverse-phase emulsion polymerization, and reverse-phase suspension polymerization are also employed. Among these methods, the reverse-phase suspension polymerization method is superior in that it can efficiently obtain spherical polymers with high molecular weight. However, when polymerization is carried out using sorbitan, long-chain fatty acid esters of sugars, higher alcohol esters of phthalic acid, etc., which are generally known as dispersants for reversed-phase suspension polymerization, gelatinized products sometimes occur and inhibit the progress of polymerization. It has the disadvantage of peeling off, and even if polymerization can be carried out conveniently, the resulting polymer particles are extremely fine, making it difficult to pass through the mouth. At least one macromolecule solvable in a liquid monomer phase and at least one macromolecule solvable in an organic medium are used as a dispersant to prevent the formation of gelled products and obtain a polymer with a large particle size. A method of carrying out reverse-phase suspension polymerization using a macromolecular compound consisting of 100% has been proposed (Japanese Patent Publication No. 1985-8521). However, even this method has disadvantages such as gelation and aggregation of particles during polymerization depending on the combination of the type of dispersant and the type of polymerization monomer, etc., and is not fully satisfactory industrially. 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 any inconvenience as described above. 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 inventors have discovered that it can be manufactured, and have completed the present invention. That is, the present invention involves adding methacrylic acid and oil to an ethylene-propylene-diene monomer copolymer as a dispersant in an organic medium that is substantially incompatible with the dissolved mixture of a water-soluble ethylene monomer and water. A stable spherical water-soluble polymer obtained by carrying out polymerization in the presence of lower fatty acids in a method of producing a polymer by a reverse-phase suspension polymerization method using a graft copolymer of a soluble ethylene monomer. To provide a manufacturing method. The method of the present invention is effective in reverse-phase suspension polymerization of a dissolved mixture of water and water-soluble monomers, mainly water-soluble ethylene monomers. In carrying out 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 monomer copolymer (hereinafter abbreviated as EPDM) is used as a dispersant. Further, as the lower fatty acid to be present, a lower fatty acid that is soluble in the monomer aqueous solution is used. When carrying out reverse phase suspension polymerization of a dissolved mixture of water and a water-soluble monomer mainly consisting of a water-soluble ethylene monomer having a quaternary amino group in an organic medium that is substantially incompatible with the mixture, When a graft copolymer obtained by graft-polymerizing methacrylic acid and an oil-soluble ethylene monomer to EPDM is used as a dispersant, a polymer that shows almost no dispersion ability and gels in lumps is produced. Water-soluble fatty acid monomer 100%
1 to 50 parts by weight, preferably 3 to 25 parts by weight
If part by weight is co-present, reverse phase suspension polymerization will proceed stably and a spherical polymer with an average particle size of 50 to 1000 microns will be obtained. If the amount of lower fatty acids is less than 1 part by weight, stable dispersion will not be achieved and a gelatinized product will be formed, while if it is more than 50 parts by weight, a large amount of lower fatty acids will remain in the product polymer, which is not preferable. Examples of the lower fatty acids used in carrying out the method of the present invention include acetic acid, propionic acid, butyric acid, and lactic acid. In the method of the present invention, ethylene-
A graft copolymer obtained by graft-polymerizing methacrylic acid and an oil-soluble ethylene monomer to a propylene-diene copolymer is used. Such a graft copolymer is generally prepared by mixing an ethylene-propylene-diene monomer copolymer, methacrylic acid, an oil-soluble ethylene monomer, and an oil-soluble radical initiator dissolved in an organic solvent, preferably under a nitrogen atmosphere, with stirring. is a milky non-aqueous emulsion or solution obtained by polymerization at a temperature of 40°C or higher and 100°C or lower. In carrying out the method of the present invention, it is essential that one component of the graft monomer is methacrylic acid, and this monomer makes it possible to produce a polymer having a large particle size with good dispersion.
The oil-soluble ethylene monomers include ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-hydroxyethyl methacrylate,
2-hydroxypropyl methacrylate, methyl methacrylate, styrene, ethyl acrylate, butyl acrylate, 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 30 to 90 parts by weight of EPDM, 2 to 40 parts by weight of methacrylic acid, assuming that the total is 100 parts by weight.
The content of the oil-soluble ethylene monomer is preferably 2 to 40 parts by weight. If it is out of the above range, the dispersibility will decrease, which is not preferable. 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. If the dispersant is less than 0.05% by weight of the monomer solution, the dispersing ability will be insufficient, while if it exceeds 4% by weight, insoluble matter will increase in the product, so it is generally 0.05 to 4% by weight, Preferably, it is used in an amount of 0.1 to 2% by weight. Examples of water-soluble ethylene monomers used in the method of the present invention include dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dipropylaminoethyl methacrylate, dimethylaminopropyl methacrylate, diethylaminopropyl methacrylate, dipropylaminopropyl methacrylate, and vinylpyridine. Salts obtained by quaternizing amino groups with alkyl halides such as methyl chloride, ethyl chloride, methyl bromide, and ethyl bromide, alkylating agents such as dimethyl sulfate, and water-soluble ethylene monomers such as acrylic acid, methacrylic acid, and maleic acid. , fumaric acid, itaconic acid, metal salts or ammonium salts thereof such as sodium or potassium, acrylamide, N-vinylpyrrolidone, and the like. In particular, the method of the present invention uses 70% by weight of a water-soluble ethylene monomer containing a quaternary amino group alone or other water-soluble ethylene monomer copolymerizable therewith.
A mixture with the following amounts is effective for copolymerization. Organic liquids used as media include aliphatic hydrocarbons such as butane, pentane, hexane, heptane, octane, and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, and chlorine such as chloroform, dichloromethane, ethyl chloride, and dichloroethane. Hydrocarbons, etc. can be used. The charging ratio of the water-soluble ethylene monomer aqueous solution to the organic liquid is preferably 150 to 600 parts by weight of the organic liquid per 100 parts by weight of the monomer aqueous solution. 150
If it is less than 600 parts by weight, the dispersion stability will deteriorate, and if it exceeds 600 parts by weight, the volumetric efficiency will be significantly deteriorated, making it economically undesirable. As the radical initiator, a water-soluble radical initiator such as potassium persulfate, ammonium persulfate, hydrogen peroxide, or a combination system of these with a suitable reducing agent such as sodium bisulfite, sodium thiosulfite, sodium pyrosulfite, or Rongarit is used. Water-soluble azo initiators such as 2,2'-(azobis-2-amidei)pumpane dihydrochloride and azobiscyanopentanoic acid are preferably used. The amount of initiator used is not particularly limited, but it is preferably 0.005% by weight or more and 1% by weight or less based on the monomer. According to the method of the present invention as described in detail above, the polymer does not gel during the polymerization, and operational difficulties such as inability to stir and damage to the equipment can be avoided. effect can be achieved. Furthermore, since the water-soluble polymer produced by the method of the present invention is spherical and has a large particle size, it has the great advantage that it can be easily separated. Hereinafter, the method of the present invention will be explained in more detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples. Example 1 (Synthesis of dispersant) 425 g of hexane was placed in a separable flask equipped with a stirrer, a Dimroth condenser, and a thermometer.
After charging 52.5 g of EPDM (trade name: Esprene 301A, manufactured by Sumitomo Chemical Co., Ltd.) and dissolving it under reflux, 11.3 g of methacrylic acid, 11.3 g of butyl methacrylate, and 0.22 g of azobisisobutyronitrile were added at room temperature, and the mixture was heated under a nitrogen atmosphere. The temperature was raised to 66°C and the mixture was reacted for 12 hours. The obtained dispersant was a white emulsion with a solid content concentration of 14.4% by weight. (Production of water-soluble polymer) In a separable flask equipped with a stirrer, a Dimroth condenser, a thermometer, and a dropping funnel, add 80 g of quaternary salt obtained by quaternizing dimethylaminoethyl methacrylate with methyl chloride, and 20 g of acrylamide.
g, water 40g, acetic acid 5g, potassium persulfate 0.03g,
350g of hexane and the dispersant solution synthesized above 14
I prepared g. After purging with nitrogen, the temperature was maintained at 10° C. while stirring at 600 rpm, and a 1.5% by weight aqueous solution of sodium bisulfite was added dropwise from the dropping funnel at a rate of 1.5 ml/hour over 2 hours. After finishing the dripping, add 0.5g of sorbitan monolaurate.
was added, the temperature was raised to reflux temperature, and azeotropic dehydration was performed for 2 hours to remove 20 g of water from the system. The resulting suspension was uniformly dispersed. This suspension was filtered through a glass filter, the polymer was washed with 100 ml of hexane, and then dried under reduced pressure at 60° C. for 24 hours. The obtained polymer was spherical with an average particle diameter of 190μ, and [η]=4.5 (30°C in 1N NaNO ₃ aqueous solution). Comparative Example 1 An experiment similar to Example 1 was conducted except that acetic acid was not added, but from the start of dropping sodium bisulfite,
After a few minutes, the mixture gelled into lumps and no dispersed particles were obtained. Example 2 In an experiment similar to Example 1, propionic acid, butyric acid, or lactic acid was charged in the amount shown in Table 1 instead of acetic acid, and polymerization was carried out. When the obtained polymer was treated in the same manner as in Example 1, a polymer having the average particle diameter and viscosity shown in Table 1 was obtained.

[Table] Example 3 In a separable flask equipped with a stirrer, a Dimroth condenser, and a thermometer, 60 g of quaternized salt quaternized with dimethylaminoethyl methacrylate and ethyl bromide, 40 g of acrylamide, 40 g of water,
10 g of acetic acid, 0.02 g of potassium persulfate, 350 g of cyclohexane, and the dispersant solution synthesized in Example 1 14
I prepared g. After purging with nitrogen, the temperature was raised to 50°C with stirring at 600 rpm and polymerized for 2 hours. After adding 0.5 g of sorbitan monostearate and polymerizing with stirring for an additional 4 hours, the temperature was raised to reflux temperature and azeotropically dehydrated for 1 hour. 20g of water was removed from the system. The resulting suspension was passed through a 350 mesh wire mesh,
After further washing with 100ml of cyclohexane,
It was dried under reduced pressure at ℃ for 24 hours. The obtained polymer was spherical with an average particle diameter of 220μ, and [η]=3.8 (1N NaNO ₃ aqueous solution). For comparison, a similar experiment was conducted without adding acetic acid, and as a result, the polymer gelled into lumps 30 minutes after the start of polymerization and could not be obtained as particles.

Claims (1)

[Claims] 1. A dissolved mixture of a water-soluble ethylene monomer and water in an organic medium that is substantially incompatible with the mixture,
In a method for producing a polymer by a reverse phase suspension polymerization method using a graft copolymer obtained by graft-polymerizing methacrylic acid and an oil-soluble ethylene monomer to an ethylene-propylene-diene monomer copolymer as a dispersant, polymerization 1. A method for producing a spherical water-soluble polymer, comprising carrying out the step in the presence of lower fatty acids. 2. The method for producing a spherical water-soluble polymer according to claim 1, wherein the lower fatty acid is present in 1 to 50 parts by weight per 100 parts by weight of the water-soluble monomer. 3. The method for producing a spherical water-soluble polymer according to claim 1, wherein the lower fatty acid is present in an amount of 3 to 25 parts by weight based on 100 parts by weight of the water-soluble monomer. 4. The method for producing a spherical water-soluble polymer according to claim 1, 2 or 3, wherein acetic acid, propionic acid, butyric acid or lactic acid is used as the lower fatty acid.