JPS591287B2 - Method for producing water-soluble polymer - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing a water-soluble polymer.

More specifically, the present invention relates to a method for producing a water-soluble polymer containing a quaternary ammonium salt of dialkylaminoalkyl (meth)acrylates as a polymer constituent unit. Water-soluble polymers containing quaternary ammonium salts of dialkylaminoalkyl (meth)acrylates as constituent units can be used as polymer electrolytes, flocculants, fiber treatment agents, paper strength enhancers, antistatic agents, synthetic fiber modifiers, It is useful as a filter aid for sludge, a fixing agent for paper sizing agents, etc.

Conventionally, the quaternary ammonium salt of dialkylaminoalkyl (meth)acrylate, which is a raw material, has been used as a quaternizing agent in a polar organic solvent such as dimethylformamide or dimethyl sulfoxide because dialkylaminoalkyl (meth)acrylates are unstable in water. The resulting quaternary ammonium salt was filtered and dried, and then subjected to polymerization alone or together with other copolymerizable monomers.

As the polymerization method, methods such as aqueous solution polymerization and suspension polymerization in an aqueous medium are employed. However, in such conventional methods, the organic solvent used in the production of the quaternized product remains attached to the ammonium salt and acts as a chain transfer agent in the polymerization process, making it difficult to obtain a polymer with a high degree of polymerization. Ta.
In addition, when the quaternized product is collected by filtration and drying from the quaternization reaction solution, a part of the quaternized product may polymerize, which may deteriorate the quality of the polymer or cause unexpected trouble in the subsequent polymerization process. There is.

As a result of repeated studies to eliminate the deficiencies in such conventional methods, the present inventors succeeded in quaternizing dialkylaminoalkyl (meth)acrylates in an aqueous medium by selecting specific conditions. However, the inventors have realized that the desired water-soluble polymer can be advantageously produced by directly subjecting the in-water quaternization reaction solution to polymerization, thereby achieving the present invention.

That is, the gist of the present invention is that the general formula (wherein R represents a hydrogen atom or a methyl group, R1 and R2
represents a lower alkyl group and Y represents a lower alkylene group or a hydroxyalkylene group) A 50 to 80% (by weight) aqueous solution of acrylate or methacrylates represented by A method for producing a water-soluble polymer, characterized in that acrylates are quaternized and then polymerized in the presence of a radical polymerization catalyst.

To explain the present invention in detail, (
Examples of meth)acrylates include dimethylaminoethyl acrylate, dimethylaminopropyl acrylate, dimethylaminobutyl acrylate, methylethylaminoethyl acrylate, diethylaminoethyl acrylate, 3-dimethylamino-2-hydroxypropyl acrylate, dibutylaminoethyl acrylate, and others. Mention may be made of the corresponding methacrylates.

In the present invention, a (meth)acrylate quaternary ammonium salt is produced by contacting an aqueous solution of such (meth)acrylates with an alkyl halide or an aralkyl halide, at which time the concentration of (meth)acrylates is 50 to 80 (
By using a highly concentrated aqueous solution, preferably 65 to 75% (weight)%, it is possible to obtain a quaternary ammonium salt in high yield without causing hydrolysis of (meth)acrylates.

If a (meth)acrylate aqueous solution with a concentration lower than the above range is used, hydrolysis of (meth)acrylate will occur;
At high concentrations, it is not only difficult to handle due to its high viscosity, but also tends to cause undesirable side reactions such as polymerization. Examples of the alkyl halide or aralkyl halide used in the quaternization reaction include methyl chloride, ethyl chloride, benzyl chloride,
Examples include methyl bromide, ethyl bromide, and ethyl iodide.

It is desirable to keep the reaction temperature as low as possible; if it is carried out at a high temperature, hydrolysis and undesirable side reactions are likely to occur.

The temperature is usually selected from the range of 10 to 50°C, preferably 25 to 40°C. Further, in order to avoid polymerization during the quaternization reaction, a known polymerization inhibitor may be added.

After the completion of the quaternization reaction, if necessary, unreacted alkyl halide or aralkyl halide is removed by appropriate means to obtain an aqueous solution of (meth)acrylate quaternary ammonium salt, which can be used as it is as an aqueous solution of polymerization reaction monomers. For the polymerization, a conventional method used for the polymerization of water-soluble vinyl compounds of this type using a radical polymerization catalyst is employed. For example, as a polymerization catalyst, a peroxide such as ammonium persulfate, potassium persulfate, sodium chlorate, benzoyl peroxide, an azo compound such as azobisisobutyronitrile, or a redox catalyst such as ammonium persulfate and sodium bisulfite, Polymerization is carried out using ammonium persulfate, sodium thiosulfate, etc., and by a method such as aqueous solution standing polymerization or suspension polymerization.

In the case of suspended polymerization, an aqueous monomer solution is suspended in an organic solvent such as cyclohexane, benzene, toluene, etc., and polymerized. Furthermore, in addition to the quaternary ammonium salt, unsaturated monomers such as acrylamide, methacrylamide, vinyl acetate, styrene, acrylonitrile, and methyl methacrylate may be added as monomers for copolymerization.

According to the method of the present invention, there is no need for complicated operations such as separation and purification of quaternary ammonium salts, and there is no risk of molecular weight reduction due to chain transfer of residual organic solvents. can be obtained.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 (Quaternization reaction) In a 100CC pressure-resistant glass reactor equipped with a three-necked electromagnetic stirrer, 18.75% of dimethylaminoethyl methacrylate and 7.7% of water were added.
57 and further added 100 ppm of methylhydroquinone as a polymerization inhibitor to the aminoacrylate.

Methyl chloride pressure (3.

5 to 4.5 atm, room temperature 25 to 30°C) and reacted for 3 hours.

After the reaction is completed, the reaction system is slowly returned to normal pressure and excess methyl chloride is removed from the system. In this way, an aqueous solution of a quaternary ammonium salt of dimethylaminoethyl methacrylate (quaternization rate: 99.6%) was obtained. (Polymerization reaction) Quaternary ammonium salt aqueous solution obtained in the above reaction 3.82
Add 6.08 y of water to y, add 0.17 y of 10% ammonium persulfate aqueous solution as a catalyst, and heat at 50°C after replacing with nitrogen.
Stationary polymerization was carried out for a period of time.

After the polymerization was completed, acetone was added to precipitate the polymer.
The yield of the produced polymer was 86%, and the ring element viscosity ηSp/C was 3.
．． It was 3. (ηSp/C was measured using a 1N NaCl aqueous solution at a polymer concentration of 0.1% and 30°C. Comparative Example 1 Methyl chloride gas was blown into 100 y of dimethylformamide and dissolved for 7.5 y.

Add 15% of dimethylaminoethyl methacrylate to this solution.
77 was added and reacted at 50°C for 4 hours. As the reaction progressed, the quaternized monomer turned into powder and a slurry was obtained. The slurry was separated using a Nutssie filter, and then thoroughly washed (twice) with 100 ml of benzene. The obtained powder is 177! Dry at room temperature under a vacuum of UHg for 4 hours. A trace amount of polymer was present in this crystalline monomer. Using this monomer, static polymerization was carried out at 50 DEG C. for 3 hours at the same monomer concentration and catalyst concentration as in Example 1, and the yield was 85% and .eta.Sp/C-2.1. Example
2 0.4% benzyl chloride based on the ammonium salt was added to the quaternary ammonium salt aqueous solution obtained in Example 1, and the solution was heated to 1.
Stirred for hours to react 847, water 251? , acrylamide 537, 1% triethylamine aqueous solution 87,
Cyclohexane 4007 and polyoxyethylene nonyl phenyl ether emulsifier 107 were charged into a four-loop flask, and nitrogen was added. Substitution was carried out, and finally 3.2 g of a 10% aqueous ammonium persulfate solution was added to carry out emulsion polymerization.

After 2.5 hours, the reaction product was dehydrated with acetone to obtain a white powdered polymer.

The yield was 99%, ηSp/C=6.5.

Comparative Example 2 Using the powdered quaternized monomer synthesized in Comparative Example 1, polymerization was carried out under the same conditions as in Example 2. The yield was 9.
9%, ηSp/C=6.0.

The monomer used was partially polymerized, and the emulsification was not complete and there was a slight amount of deposits.

Claims (1)

[Claims] 1. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R represents a hydrogen atom or a methyl group, and R^1 and R
^2 represents a lower alkyl group, Y represents a lower alkylene group or a hydroxyalkylene group) A 50 to 80% (by weight) aqueous solution of an acrylate or methacrylate is contacted with an alkyl halide or an aralkyl halide to form the acrylate or methacrylate. A method for producing a water-soluble polymer, which comprises quaternizing a compound and then polymerizing it in the presence of a radical polymerization catalyst.