JPS61138607A - Polymerization of water-soluble cationic polymer - Google Patents

Abstract

PURPOSE:To obtain a water-soluble cationic polymer useful as a flocculant for waste-water treatment, dehydration agent, and paper chemicals, easily and economically, in the form of precipitate, by (co)polymerizing a specific cationic monomer in the precipitation polymerization of the objective polymer in an aqueous solution of a salt. CONSTITUTION:A cationic monomer of formula (R1 is H or CH3; R2 and R3 are 1-3C alkyl; A is O or NH; B is 2-4C alkylene or hydroxypropylene; X<-> is anionic counter ion)[e.g. dimethylaminoethyl (meth)acrylate] and other monomer copolymerizable therewith [e.g. (meth)acrylamide] are polymerized at a molar ratio of 100:0-5:95 in an aqueous solution of a salt (e.g. NaCl, Na2SO4, etc.) which does not dissolve the (co)polymer of said monomers. The objective polymer is obtained as a precipitate.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a novel method for polymerizing cationic water-soluble polymers used as flocculants for wastewater treatment, dehydrating agents, and papermaking chemicals used in papermaking processes. It is something.

(Prior art) Conventionally, methods for producing cationic water-soluble polymers used as flocculants for wastewater treatment or as agents for paper manufacturing include static polymerization in an aqueous solution and water-in-oil emulsion polymerization (
JP-A-54-102388) and suspension polymerization in a hydrophobic solvent (JP-A-54-69196). Furthermore, precipitation polymerization in an aqueous ammonium sulfate solution has been disclosed as a method for obtaining nonionic or anionic water-soluble polymers (Japanese Patent Laid-Open No. 70489/1989).

(Objective of the invention) The present invention overcomes the above drawbacks and obtains a polymer as a precipitate by polymerizing or copolymerizing a cationic monomer by precipitation polymerization of a cationic water-soluble polymer in an aqueous salt solution. The purpose is to provide a method to do so.

(Problems to be Solved by the Invention) In the aqueous solution stationary polymerization method, in order to obtain a high molecular weight polymer, polymerization is performed at a monomer concentration of 10 weight or more.
The product is in the form of a water-containing lump and is difficult to dissolve as it is, so it must be further diluted to sell as a fluid, low-concentration solution, or it must be dried and powdered. When commercially available at a low concentration, transportation costs are high, and when powdered, it is inefficient if it is left in a hydrated form, so it must be chopped using a meat chopper, etc., which complicates the manufacturing process. have.

Water-in-oil emulsions are flammable and have the disadvantage of wasting valuable organic solvents.
Since suspension polymerization in a hydrophobic solvent uses flammable substances such as cyclohexane and toluene, it has the drawback of requiring a large amount of production equipment.

JP-A-50-70489 discloses a method of precipitation polymerization in ammonium sulfate, which is a good method with low cost in terms of equipment. However, the specification only describes a polymerization method for nonionic or anionic polymers, and when this method is applied to the production of cationic water-soluble polymers, the commonly used trimethylaminoethyl methacrylate When copolymerizing cationic polymers, they were dissolved without precipitation, and the production of cationic polymers was still unfinished.

(Means for Solving the Problems) The present inventors overcame these drawbacks and conducted various studies on precipitation polymerization of cationic water-soluble polymers in salt aqueous solutions. It has been found that precipitation polymerization in an aqueous salt solution is possible by polymerizing or copolymerizing a polyester, and the present invention was achieved based on this finding.

That is, the present invention comprises one or more cationic monomers represented by the following formula (I) and other monomers copolymerizable therewith in a molar ratio of 100:0 to 5=95. Polymerization of a cationic water-soluble polymer, characterized in that the polymerization is carried out in an aqueous salt solution that does not dissolve the monomer polymer or copolymer, and the polymer is obtained as a precipitate. It is about the method.

(In the formula, R1 is H or OH3; R2+ R3 is an alkyl group having 1 to 3 carbon atoms; A is an oxygen atom or NH; B is an alkyne group or hydroxypropylene group having 2 to 4 carbon atoms; X- is an anionic counter ion ) This formula (I
) are representative of the cationic monomers shown in
Examples include those obtained by quaternizing dimethylaminoethyl (meth)acrylate, diethylamine ethyl (meth)acrylate, dimethylaminohydroxypropyl (meth)acrylate, and trimethylaminozolopyl (meth)acrylamide with benzyl chloride. Any monomer satisfying I) can be used.

Representative examples of monomers copolymerizable with the cationic monomer of formula (I) include (meth)acrylamide, N,N-methyl(meth)acrylamide, dimethylaminoethyl (
Examples include meth)acrylates and their quaternized products with methyl chloride, trimethyl sulfate, etc., dimethylaminopropyl (meth)acrylamide and their quaternized products with methyl chloride, trimethyl sulfate, etc., and other monomers There are no particular limitations on the copolymer as long as the copolymer is water-soluble. Furthermore, hydrophobic monomers such as styrene and methyl methacrylate can also be used in amounts that maintain water solubility of the copolymer. It is also possible to copolymerize two or more types of copolymerizable monomers.

In the method of the present invention, a polymer can be obtained as a precipitate both in homopolymerization of the cationic monomer of formula (I) and in copolymerization using up to 95 mol of other copolymerizable monomers. can.

Regarding the aqueous salt solution used in the present invention as a dispersion medium for polymerization, it is necessary that the polymerization product is not misunderstood. Typical salts include sodium sulfate, ammonium sulfate, magnesium sulfate, aluminum sulfate, sodium chloride, sodium dihydrogen phosphate, or a mixture of two or more of these salts. Salts other than these are within the scope of the present invention as long as they do not dissolve the polymerization product.

The concentration of the aqueous salt solution is not particularly limited, depending on the molar ratio of the cationic monomers of formula (I) and the salt used, but is
A range of 5% by weight or more up to the limits of solubility is generally preferred.

Next, the polymerization method will be described in detail in Examples, but its outline is as follows.

A predetermined monomer is charged into an aqueous salt solution, deoxygenated with nitrogen gas, a polymerization initiator is added, and polymerization is started while stirring. When the polymerization is completed, polymer particles having a particle size of 2 to 3 square meters are separated. The monomer concentration at this time may be any amount of 5 parts by weight or more based on 100 parts by weight of the aqueous salt solution, and if it is less than 5 parts by weight, the efficiency will be poor.

The polymerization temperature varies depending on the type of polymerization initiator, and is not particularly limited as long as it is a temperature at which the initiator functions. Also,
The polymerization initiator is not limited and may be any commonly used redox type or azo type.

This precipitated polymer can be separated from the aqueous salt solution using a door cloth, etc., transferred to a drying process, and sold as a powder product.
It can also be commercially available by increasing the viscosity and forming a stable dispersion.

(Function) The feature of the present invention is that a specific monomer, that is, the formula (
The monomer containing I) is polymerized under stirring, and the resulting polymer is obtained as a precipitate.

At this time, the salt aqueous solution is used to prevent the formed polymer from dissolving. The cationic monomer of formula (summer) has a highly hydrophobic benzyl group bonded to the amino group, and as a result, despite being a cationic water-soluble polymer, it becomes difficult to dissolve in salt aqueous solutions and separates. .

(Examples) Next, the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Example 1 112.5 ml of ammonium sulfate was placed in a 5-necked 16-2 pull flask equipped with a thermometer, nitrogen inlet, reflux condenser, and stirrer. , ion exchange water 337.5 f.

Acrylamide 35.1? and acryloyloxyethyltmethylbenzyl ammonium chloride 14.9
f was charged, stirred to dissolve, heated to 5,000 ℃, and purged with nitrogen.

To this, 1% of 2,2'-azobis(
2-aminogro-sen) hydrochloride aqueous solution was added and polymerized for 10 hours at 5oC under stirring, resulting in a particle size of 2-3+ m.
A precipitate of i was obtained.

Example 2 Into the same gable flask used in Example 1, 951% sodium sulfate and 380% ion-exchanged water were added. , acrylamide 1
7.6F and acryloyloxyethyldimethylpennolammonium chloride 7.42 were charged, stirred to dissolve, heated to 50°C, and purged with nitrogen.

To this, 1 liter of 2,2'-azobis(2-amidinopropane) hydrochloride aqueous solution was added and stirred at 5 o'clock for 10 min.
After time polymerization, a precipitate with a particle size of 2 to 3 mm was obtained.

Example 3 Into the 7-paraple flask used in Example 1, 127.5 f of ammonium sulfate and 297.5 f of ion-exchanged water were added. .

Methacryloyloxyethyldimethylbennolammonium chloride 75? Prepare, stir and dissolve, 5
It was heated to 0°C and replaced with nitrogen.

To this, 0.75 f of 10% 2,2'-azobis(2-amitunopropane) hydrochloride aqueous solution was added, and the mixture was stirred for 5 minutes.
After 10 hours of polymerization in ooc, a precipitate with a particle size of 2-3 m was obtained.

Example 4 Add 45f of aluminum sulfate, 45t of sodium sulfate, and 3 t of ion-exchanged water to the same gable flask used in Example 1.
60? , 21.8 F of methacryloyloxyethylammonium chloride, and 28.2 F of acryloyloxyethyl dimethylbenzyl ammonium chloride were charged, stirred to dissolve, heated to 50°C, and purged with nitrogen.

To this was added 0.51 of an aqueous solution of 2,2'-azobis(2-amidinopropane) hydrochloride and polymerized with stirring at 50°C for 10 hours, yielding a precipitate with a particle size of 2 to 3 cm. .

Example 5 Into the separable flask used in Example 1, add 157.5 f1 of sodium dihydrogen phosphate and 292.52 f1 of io/exchanged water.
1 Acrylamide 15. 'l, acrylamide propylzmethylbennolammonium chloride 34°11
was charged, stirred to dissolve, heated to 50°C, and purged with nitrogen.

In addition to this, 5chi of 2,2'-azobis (2-amitsunopro,
0.51 of an aqueous hydrochloride solution was added and polymerized for 10 hours at 0C with stirring, yielding a precipitate with a particle size of 2 to 3 mm.

Example 6 The polymers obtained in Examples 1 to 5 were dried separately using a cloth, and ground as necessary to obtain powdered polymers. The pure content of the polymer was determined by correcting these moisture and salt content, and the viscosity of the polymer at a low concentration of 5% was measured in a 3% sulfuric acid aqueous solution, and the results were as shown in Table (I).

Table (I) Example 7 When homopolymer 51 of methacryloyloxyethyltrimethylammonium chloride was added and dissolved in the aqueous salt solution containing the polymer obtained in Example 1, the viscosity increased and the adhesion of the particles decreased. A stable polymer dispersion was obtained.

(Effects) As can be seen from Examples 6 and 7, the cationic water-soluble polymer obtained by the polymerization method of the present invention has a particle size of 2 to 3 fi, so it can be easily dried and A stable polymer dispersion can be obtained by adding a polymer that dissolves in an aqueous salt solution.

Claims (1)

[Claims] 1. One or more cationic monomers represented by the following formula (I) and another monomer copolymerizable therewith in a molar ratio of 100:0 to 5. : When copolymerizing in the range of 95, the polymerization is carried out in an aqueous salt solution that does not dissolve the polymer or copolymer of the monomer, and the polymer is obtained as a precipitate.Cationic water-soluble. Method of polymerization of polymers. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R_1 is H or CH_3; R_2 and R_3 are alkyl groups with 1 to 3 carbon atoms; A is an oxygen atom or NH; B is an alkyl group with 2 to 4 carbon atoms. alkylene group or hydroxypropylene group; X is an anionic counterion).