JPS60233111A - Manufacturing method of acrylamide polymer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing an acrylamide polymer.

[Conventional technology and its problems]

Acrylamide-based polymers are water-soluble polymers and are widely used, for example, as flocculants. Polymerization is usually carried out in an aqueous solution, but when used as a flocculant, it is desirable that the molecular weight of the polymer is as large as possible. In order to obtain a polymer with a large molecular weight, it is usually necessary to reduce the amount of polymerization catalyst used and to carry out the polymerization at a low temperature. fC, the solubility of the polymer in water tends to decrease when attempting to produce a polymer with a high molecular weight. For example, when using a redox catalyst consisting of acidic sodium sulfite, potassium persulfate, or ferrous sulfate-hydrogen peroxide, the oxidizing agent itself can initiate polymer crosslinking at a low temperature. Furthermore, when an azo catalyst such as λ'-azobisamidinopropane hydrochloride is used, polymerization starts slowly at low temperatures, and if the amount used is small, the polymerization rate may increase. The remaining monomers therefore tend to crosslink the polymer. So far, methods have been proposed in which a redox catalyst and an azo catalyst are combined as polymerization catalysts, but these methods are still not satisfactory.

[Means for solving problems]

The Ministry of Invention, etc. has the ability 1. As a result of various studies on methods of producing a higher molecular weight acrylamide polymer powder without reducing its solubility in water, it was found that polymer 1 satisfying these conditions could be obtained by using a stannous compound as a polymerization catalyst. They discovered that it is possible to do this, and completed the present invention.

The Honkai Meikai will be explained in detail below.

When polymerizing an aqueous monomer solution containing acrylamide, the polymer used is usually acrylamide alone or a combination of acrylamide and, for example, (meth)acrylic acid, sodium (meth)acrylate, ethyl (meth)acrylate, etc. A mixture with anionic monomers appears.

In the present invention, the combination of acrylamide and anionic monomer 1
The content of the anionic monomer in the monomer mixture is usually from /-jO mol, preferably from 3" to po mol. is not particularly limited, and for example, a method of obtaining a polymer as an aqueous solution or a water-containing gel by charging an aqueous seven-mer solution into a polymerization tank as it is and subjecting it to adiabatic polymerization, or mixing the entire aqueous monomer solution in an organic solvent. Examples include a method of obtaining a polymer in the form of whole powder or beads by emulsification or suspension polymerization.

The concentration of the monomer aqueous solution varies depending on the type of polymerization, but is usually selected from a range of 10-to-itf%.

31 The present invention requires the use of a 7th tin compound in monomanila polymerization as described above. Examples of the stannous compound include stannous chloride, stannous sulfate, stannous acetate, stannous iodide, stannous oxalate, stannous sulfide, stannous tartrate, and stannous oxide. Examples include stannous, and among these, water-soluble inorganic acid salts are preferred. The amount of this compound to be used is usually / -, 5000 ppm, preferably 1
If the amount is too small, polymerization will not be carried out well, and if it is too large, a polymer with a high molecular weight will not be obtained.

The polymerization catalyst of the present invention may be added to the polymerization system by any method, but it is usually preferable to treat it as an aqueous solution.

Further, the polymerization catalyst of the present invention can also be used in combination with conventionally known redots, couscous catalysts, or azo catalysts. For example, acidic sodium sulfite, ar
Examples of azo catalysts include combinations of reducing agents such as ferrous iron and triethanolamine with oxidizing agents such as potassium persulfate, ammonium persulfate, hydrogen peroxide, and benzoyl peroxide.
Examples of 'i1 include coazobi, samidinopropane hydrochloride, λ,-'-azobis(lIt-methoxy-4,≠-dimethylvaleronitrile), and the like. Furthermore, in the present invention, various additives such as urea, ethanol, amines, λ-mercaptobenzothiazole, and ethylenethiourea may be used in combination.

The polymerization conditions in the present invention are not restricted in any way, but are usually at a temperature of io to 1ooC and a temperature of O0j to 70C.
time, polymerized. There is no need to particularly adjust the pH during polymerization, but depending on the target monomer, the pH may range from 2 to 2.
Adjusted to IO range. In this case, if the pH is in the alkaline range, a part of acrylamide will be hydrolyzed and an anionic polymer will be obtained. The polymer after polymerization is usually dried according to a conventional method, and finally recovered as a powder or bead-like product having a water content of 10% or less.

〔Effect of the invention〕

As described above, according to the present invention, by using a specific compound as a polymerization catalyst when polymerizing a monomer containing acrylamide, a polymer having a high molecular weight and good water solubility can be obtained. be. Therefore, the method of the present invention can produce a flocculant with higher performance.

〔Example〕

Next, the present invention will be explained in detail with reference to examples, but the present invention is not limited to the following examples as long as the purpose is not exceeded.

Examples 1 to 3 and Comparative Examples/~ Acrylamide 2/II r, acrylic acid 2≠tv, and water 721rO were placed in a polymerization tank whose inner surface was coated with polyethylene.
Add 4 tons of 7% aqueous sodium hydroxide solution consisting of
After aerating the system with nitrogen gas at a temperature of 0C, a polymerization catalyst shown in Table m7 was charged as an aqueous solution, and polymerization was carried out for 5 hours.

After polymerization, the resulting hydrogel-like polymer is finely granulated and then dried with hot air at a temperature of toC for 2 hours to form a hydrous -j7f.
i110ju-jli! -% or less of granular polymer was obtained.

The granular polymer thus obtained was measured for viscosity and examined for solubility in water, and the results shown in Table 1 were obtained.

Table 1 7- Note 1) Measuring method of viscosity Viscosity in CojC when polymer f is dissolved in saline solution at 96% by weight. Aj rotor).

Note 2) Solubility in water The state of the polymer when dissolved in clean water to form an aqueous solution of Polymer 1)/Xi% was determined according to the following criteria.

= 8- 〇・・・・・・Completely dissolved in water △・・・・・・There is some insoluble matter ×・・・・・・
...Contains a considerable amount of insoluble matter Note 3) An azo catalyst, 2.2'-azobisamidinofuropane salt #R salt, was used.

Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - Others/names

Claims (5)

[Claims] (1) A method for producing an acrylamide-based polymer, characterized in that a stannous compound is used as a polymerization catalyst in polymerizing an aqueous monomer solution containing acrylamide. (2) The method according to claim 1, wherein the stannous compound is a water-soluble inorganic acid salt. (3) The amount of polymerization catalyst used is /~11 relative to the monomer.
Claim 1 characterized in that it is 000pp.
The method described in section. (4) The method according to claim 1, wherein the monomer is a mixture of acrylamide and an anionic monomer, and the content of the anionic monomer in the monomer mixture is /~jOmol. (5) The method according to claim V, wherein the anionic monomer is sodium (meth)acrylate.