JPS6050809B2 - Method for producing acrylamide polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an acrylamide polymer.

Specifically, the present invention relates to a method for producing an acrylamide polymer that has excellent solubility and flocculating ability and is particularly suitable as a flocculant. Polyacrylamides are used for many purposes such as flocculants, soil settling agents, and paper strength enhancers. Among these, flocculants are in the spotlight because they have excellent effects on various types of wastewater. Regardless of the application, polyacrylamides are required to have excellent solubility and flocculating ability, and the requirements for use as flocculants are particularly severe.

However, it is generally recognized that when either solubility or aggregation ability is improved, the other decreases.
It has been extremely difficult to improve the performance of both. The present inventors have conducted extensive research into improving the performance of polyacrylamides that have such a tendency, and have found that if acrylamides are polymerized in the presence of a specific salt,
The present invention was achieved by discovering that polyacrylamides with excellent solubility and aggregation ability and extremely high commercial value can be obtained without impairing the stability of polyacrylamides.

That is, the gist of the present invention is characterized in that when acrylamide or acrylamide and a monomer copolymerizable therewith are polymerized in an aqueous medium, an organic sulfonate containing no polymerizable unsaturated bond is present. The present invention relates to a method for producing an acrylamide polymer. To explain the present invention in detail, the acrylamide used as a raw material in the present invention is not particularly limited, and acrylamide is reacted with water and sulfuric acid to form an acrylamide sulfate salt, which is then neutralized with an alkali. Acrylamide obtained by
or acrylamide obtained by catalytically hydrating acrylonitrile in the presence of a metal-containing catalyst.

In particular, when the method of the present invention is applied to an aqueous acrylamide solution obtained as an aqueous solution by the latter method, particularly excellent effects can be achieved.

Examples of monomers that can be copolymerized with acrylamide include acrylic acid, acrylic acid sorter, acrylic ester, and vinyl acetate.

As a method for polymerizing acrylamide or acrylamide and the other five monomers in an aqueous medium, well-known polymerization methods for producing acrylamide polymers such as aqueous solution polymerization and emulsion polymerization can be applied.

For example, aqueous solution polymerization is 70% or less, preferably 11 to 5
0% acrylamide aqueous solution with peroxides such as potassium persulfate, ammonium peroxide, hydrogen peroxide, benzoyl peroxide, etc.
Azobisisobutyronitrile, 2,2! -Azobis (2
-amidinopropane) dihydrochloride or the like is added in an amount of 0.001 to 2% by weight based on acrylamide, and the reaction is usually carried out by heating the mixture to 40 to 80°C. Of course, a so-called redox initiator, which is a combination of a metal salt such as sodium sulfite or a tertiary amine and a peroxide, may be used, and this polymerization can be carried out at a lower temperature. In addition, emulsion polymerization is 70% or less, preferably 30%
~60% acrylamide aqueous solution with carbon tetrachloride, chlorinated hydrocarbons such as dichloroethane, trichlorethylene, aliphatic or alicyclic hydrocarbons such as hexane or cyclohexane, or aromatic hydrocarbons such as benzene or xylene. The polymerization is carried out by emulsifying the polymer in an organic medium such as and heating in the presence of the same initiator as in the case of aqueous solution polymerization.

The weight ratio of the organic medium to the acrylamide aqueous solution is usually 1 to 3.

As the emulsifier, nonionic surfactants such as polyoxyethylene alkyl ether type, polyoxyethylene alkylphenol ether type, polyoxyethylene alkyl ester type, sorbitan alkyl ester type, polyoxyethylene alkyl amide type, or conventional surfactants can be used. Cationic and anionic surfactants are employed.

jDepending on the type of emulsifier, for example, FLB3
．． When oil-soluble emulsifiers 5 to 6 are used, a water-in-oil emulsion is formed, and when water-soluble emulsifiers FII, B8 to 18 are used, an oil-in-water emulsion is formed. The emulsifier concentration is usually between 0.0 and 5%.
3 These methods are also applied when copolymerizing acrylamide with other monomers. Therefore, in the present invention, the polymerization of acrylamide in an aqueous medium is carried out in the presence of an organic sulfonate containing no polymerizable unsaturated bonds.

Examples of organic sulfonic acid salts that do not contain polymerizable unsaturated bonds include acids such as monovalent or polyvalent saturated aliphatic sulfonic acids, alicyclic sulfonic acids, aromatic sulfonic acids, and heterocyclic sulfonic acids; Examples include salts with inorganic bases such as sodium oxide, urium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, ammonium hydroxide, and organic bases such as trimethylamine and didamethylamine.

More specific examples include sodium benzenesulfonate, sodium toluenesulfonate, sodium methanesulfonate, sodium ethanesulfonate, and salts thereof with other bases. O Industrially, the above-mentioned salts of sulfonic acid and sodium hydroxide are often employed from the viewpoint of ease of acquisition and handling, or from the viewpoint of environmental pollution.

In the method of the present invention, the amount of organic sulfonate is usually 0.05 to 5%, preferably 70.1 to 5% based on acrylamide.
1% by weight is used.

The timing of addition of the organic sulfonate is not particularly limited, and may be added immediately before or during polymerization.

Alternatively, a salt may be added to the acrylamide aqueous solution in advance. Furthermore, the present invention is achieved by the presence of a salt obtained by treating an aqueous acrylamide solution in advance with an organic or inorganic base as described above and neutralizing it with an organic sulfonic acid during polymerization. .

The polymer thus obtained is usually dehydrated by precipitation in a water-soluble solvent such as methanol or acetone, or dehydrated by azeotropic distillation, and then subjected to various uses.

The acrylamide polymer obtained by the method of the present invention has excellent solubility and flocculating ability, and exhibits excellent effects as a flocculant, particularly in treating valve wastewater.

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 the gist thereof is exceeded.

Example 1 Acrylamide aqueous solution obtained by catalytic hydration of acrylonitrile in the presence of a copper-containing catalyst (acrylamide concentration 5
%) was collected for 125y, and after adding 0.32y of sodium benzenesulfonate, demineralized water was added to make a 500y aqueous solution.

This acrylamide aqueous solution was transferred to a separable flask with an internal volume of 700 mL, and N
2 gas was blown into the flask, and 3.1 mt of a 1% by weight aqueous solution of ammonium persulfate was added. After adding ammonium persulfate,
The temperature of the water bath is raised to 50°C at a rate of 1°C per minute.

Polymerization starts during the temperature rise. The bath temperature was maintained at 50°C for 1 hour, then the bath temperature was raised to 60°C at the same rate of increase as above, and maintained at 60°C for 2 hours. After holding the flask, remove it from the bathtub and cool it with water.

A portion of the polymer thus obtained is taken out and suspended in methanol to remove water.

The white powdered polymers were dried under reduced pressure and then ground further.

The performance of the polymer thus obtained was compared with respect to the following items.

Solubility: Add 0.2q of dry polymer to a beaker.
200T111 water was added to this, and the solubility after stirring for 4 hours was compared.

0: Small lumps of gel-like polymer remain floating.

×: A large amount of gel-like polymer lumps remained. Aggregation ability:
400 ppm of sulfuric acid was added to Kraft valve wastewater, and the equivalent of 1 ppm of polyacrylamide at pH 6 was added, and flocculation was performed using a jar tester using a conventional method. Judgments were made based on the size of the flocs produced.

O mark: Diameter 3-4? Δ mark: Diameter 1 to 3 TFrIn × mark: Diameter less than 17 m Various organic sulfonate salts were similarly polymerized and the performance of the obtained polymers was tested.

Claims (1)

[Claims] 1. A water-soluble acrylamide polymer characterized by the presence of an organic sulfonate containing no polymerizable unsaturated bonds when acrylamide or acrylamide and a monomer capable of copolymerizing it are polymerized in an aqueous medium. manufacturing method.