JPS5918406B2 - Manufacturing method of water-soluble polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a water-soluble polymer,
Specifically, the present invention relates to a method for producing a polymer containing a neutralized salt or quaternized dialkylaminoalkyl (meth)acrylate (hereinafter referred to as DAA).

Homopolymer of DAA or DAA,! , a copolymer with acrylamide is widely used as a flocculant, and its production method includes, for example, adding a monomer aqueous solution to a mixture of a hydrocarbon dispersion medium, water, and dispersion stabilizer while stirring, and adding a polymerization initiator to the copolymer. A method of polymerizing in the presence of is known.

In this method, the resulting granular polymer is present in an organic dispersion medium in a water-containing state, so the mixture after polymerization is usually heated to evaporate and dehydrate to remove water, and then the polymer is separated and dried. Ru. However, since the polymer containing DAA is a water-soluble and highly adhesive polymer, there is a drawback that a large amount of polymer adheres to the inner wall of the apparatus during evaporation and dehydration.

If the amount of polymer adhering to the inner wall of the equipment increases, the heat from the heating jacket will not be effectively transferred to the inside, so it will take time to heat the mixed liquid to the specified temperature, and as a result, the evaporation and dehydration process will take longer. The drawback was that it took a long time. In view of the above circumstances, the present inventors have investigated various ways to reduce the amount of polymer adhering to the inner wall of the apparatus during evaporative dehydration, and found that it is possible to add a DAA-containing polymer having a specific water content and particle size during evaporative dehydration. The present invention was completed based on the discovery that the above-mentioned drawbacks can be significantly improved.

That is, the gist of the present invention is to use a neutralized salt or quaternized dialkylaminoalkyl (meth)acrylate monomer alone, or a mixture of the monomer and a copolymerizable monomer with a hydrocarbon dispersion medium, water, and dispersion stabilizer. When heating and evaporating and dehydrating the mixture of the granular polymer and the dispersion medium obtained by polymerizing in the presence of a polymerization initiator under stirring in a mixture of Or, a cationic water-soluble polymer whose main constituent unit is a monomer common to the produced polymer, with a water content of 15% or less and a particle size of 1♂ or less, in an amount of 1 to 30% of the produced polymer. A method for producing a water-soluble polymer, characterized by adding % by weight and performing evaporative dehydration.

The present invention will be explained in detail below. D targeted by the present invention
AA represents the following general formula (1) (wherein, R1 is a hydrogen atom or a methyl group, R2 and R3 are straight chain or branched alkyl groups having 1 to 4 carbon atoms, R2 and R3 may be the same, and R4 represents a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, a hydroxy-substituted alkyl group having 1 to 4 carbon atoms, or a benzyl group.

Y represents an alkylene group having 2 to 4 carbon atoms or a hydroxy-substituted alkylene group. X8 represents a halogen ion such as Ct or Br, a sulfate ion, a nitrate ion, a phosphate ion, a carboxylate ion, a sulfonate ion, an alkyl sulfate ion having an alkyl group having 1 to 8 carbon atoms, or the like. ) is a compound represented by.

For example, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate,
Neutralized salts of dibutylaminoethyl acrylate, dibutylaminoethyl methacrylate, etc. and acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, propionic acid, benzenesulfonic acid, etc., and β-methacryloyloxyethyltrimethylammonium chloride, β- methacryloyloxyethyltrimethylammonium methylsulfate,
β-methacryloyloxyethyldimethylethylammonium bromide, β-methacryloyloxyethyldimethylethylammonium monoethyl sulfate, β-methacryloyloxyethyldimethyl'benzylammonium chloride, β-acryloyloxyethyltrimethylammonium chloride, β-acryloyloxy Ethyltriethylammonium bromide, 2
Examples include quaternized products such as -hydroxy-3-methacryloyloxypropyltrimethylammonium chloride.

The cationic high molecular weight water-soluble polymer that is the object of the present invention is a monomer that can be copolymerized with the compound represented by the general formula (1) alone or with the compound represented by the general formula (1), such as acrylamide, methacrylamide, Examples include neutralized vinylpyridine salts or quaternized salts, and copolymers with dimethyldiallylammonium compounds. In the case of this copolymer, the content of DAA is usually 5 mol% or more, preferably 10 mol% or more. As the dispersion medium used in the present invention, it is usually preferable to select a hydrocarbon that is azeotropic with water because dehydration can be performed at a relatively low temperature, but when using a dispersion medium that is not azeotropic with water, the boiling point is ,130℃
The lowest one below is better.

Specific examples of these dispersion media include alicyclic hydrocarbons such as cyclohexane, cyclopentane, cycloheptane, methylsilclohexane, and cyclooctane, benzene,
Examples include hydrocarbons such as aromatic hydrocarbons such as toluene, xylene, ethylbenzene, chlorobenzene, and dichlorobenzene. These dispersion media are usually used in an amount of 1 to 10 times the weight of the monomer, preferably 1 to 5 times the weight of the monomer. Dispersion stabilizers typically include known surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, and polyoxyethylene nonylphenyl ester.

The amount of dispersion stabilizer used is usually 1 to 30% based on the monomer.
% by weight, preferably from 5 to 20% by weight. Examples of polymerization initiators include peroxides such as ammonium persulfate, potassium persulfate, and benzoyl peroxide; (propane) hydrochloride, azo compounds such as azobisisobutyronitrile, and combinations thereof.

The amount of polymerization initiator used is usually 10 to 1 per monomer.
0,000ppm, preferably 20-5,000ppm
is within the range of In the present invention, monomers are polymerized in the presence of a dispersion medium containing a dispersion stabilizer as described above and a polymerization initiator. Mix as an aqueous solution and stir.
While degassing the system with N2 gas, for example, 10 to 70
The polymerization is carried out at a temperature of 1 to 5 hours, preferably 30 to 60 degrees Celsius.

The polymer-containing mixture after polymerization is then subjected to azeotropic dehydration to remove water in the system to usually 10% by weight or less, preferably 5% by weight or less, but in the present invention, at this time, specific fine powder is The addition of a polymer is an essential requirement.

The water content of the finely divided polymer to be added is 15% by weight or less, preferably 10% by weight or less, and the particle size is 1 to 1, preferably 0.5 or less, particularly preferably 0.2 to 1. .

If the water content and particle size are larger than the above ranges, it is not preferable because the polymer adhering to the inner wall of the apparatus during evaporation and dehydration cannot be sufficiently suppressed. The fine powder polymer used here is preferably the same as the produced polymer, and it is usually preferable to classify the product polymer obtained from the same manufacturing process and recycle a part of it. However, it is also useful to use an appropriate cationic water-soluble polymer whose main constituent unit is a monomer common to the produced polymers and polymers, as long as the purpose of use of the produced polymer is not impaired. The amount of the finely divided polymer added is 1 to 30% by weight, preferably 5 to 20% by weight, based on the resulting polymer, and if the amount added is too small, sufficient effect cannot be achieved.

Evaporative dehydration uses a distillation apparatus with a conventional heating jacket, and heating is continued until a predetermined amount of water is removed.

After evaporation and dehydration, the mixed liquid is separated into solid and liquid according to a conventional method.
After simply drying and removing the solvent adhering to the polymer, the product polymer can be recovered. As described above, according to the present invention, polymer adhesion to the inner wall of the apparatus during evaporative dehydration is significantly suppressed.

Therefore, the heat from the heating jacket is effectively transmitted to the processing liquid, and the heating time to reach a predetermined temperature is shortened, which is preferable.Next, the present invention will be explained in more detail by examples, but the gist of the present invention is as follows. It is not limited to the following examples as long as it does not exceed.

Example 1 Cyclahexane 35 was added as a dispersion medium to a reactor equipped with a thermometer, a jacket for temperature adjustment, an N2 gas inlet, and a stirrer.
09, polyoxyethylene nonyl phenyl ether 99 and β-methacryloyloxyethyltrimethylammonium chloride (hereinafter referred to as DMC) 103 g and AAM 23 g (DMCt/AAM=0.6) as dispersion stabilizers.
A 45wt0/) monomer aqueous solution 2809 containing (0.4 molar ratio) was charged, and the system was stirred to form a stable oil-in-water emulsion.N2 gas was then blown in to degas the mixture. The temperature was raised to 50°C, and 2,2″-azobis(2-amidinopropane) hydrochloride 0.3789 (3,00% based on monomer) was added as a polymerization initiator.
0 ppm) was added, and polymerization was carried out for 5 hours while maintaining the temperature in the range of 60 to 70°C.

After completion of polymerization, the mixture containing the water-containing polymer with a particle size of 1~'2~ is transferred to a jacketed container equipped with a distillation device on the top, and the following mixture is added with a water content of 10wt01) and a particle size of 0.2~. Polymer powder of the same composition is produced 1 for the polymer
0 wt % was added, and the mixture at a liquid temperature of 70° C. was heated to 800 C (temperature at which the water content in the polymer was 5 wt %), and dehydration was performed using an azeotropic composition of cyclohexadi-water. The mixture after azeotropic dehydration was filtered through F to remove the polymer, and then dried at 90° C. for 1 hour to recover a polymer having a particle size of 0.2 to 2.0.

The time required to raise the temperature for azeotropic dehydration by the above operation was measured, and the results shown in Table 1 were obtained.

Examples 2 to 3 The same treatment as in Example 1 was carried out except that the amount of polymer fine powder added during azeotropic dehydration was changed to the amount shown in Table 1.

Comparative Example The same treatment as in Example 1 was carried out without adding polymer fine powder during azeotropic dehydration.

Claims (1)

[Scope of Claims] 1 Neutralized salt or quaternized dialkylaminoalkyl (meth)acrylate monomer alone, or a mixture of the monomer and a copolymerizable monomer, from a hydrocarbon dispersion medium-water-dispersion stabilizer. When heating and evaporating a mixture obtained by polymerizing the granular polymer and the dispersion medium with stirring in the presence of a polymerization initiator in a mixture of the following: A cationic polymeric water-soluble polymer whose main constituent unit is a monomer common to the produced polymer, with a water content of 15% or less and a particle size of 1 m/m or less, is added in an amount of 1 to 30% of the produced polymer. A method for producing a water-soluble polymer, which comprises adding % by weight and performing evaporative dehydration. 2. The method for producing a water-soluble polymer according to claim 1, which uses a hydrocarbon dispersion medium that is azeotropic with water.