JPS61118406A - Production of water-soluble polyvinylamine - Google Patents

Abstract

PURPOSE:N-vinylformamide polymer is combined with ammonia or an amine, then subjected to basic hydrolysis to give a water-soluble polyvinylamine of high molecular weight and high quality. CONSTITUTION:N-vinylformamide polymer is combined with ammonia, a primary or secondary amine such as methylamine or N-methylethanolamine, preferably in an amount of 0.01-0.2 equivalent per the amide groups in the polymer and they are kept usually at 10-80 deg.C for 10-200min, then the hydrolysis is carried out using a basic substance such as sodium or potassium hydroxide. EFFECT:Hydrolysis can be effected by no use of a strong acid which tends to hurt the polymerizer. It is in no need of purification of N-vinylformamide polymer. USE:Coagulant for organic sludge, water-filtration improver or loading yield improver in paper industry.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a water-soluble polyvinylamine having excellent performance as a flocculant for dewatering organic sludge, a furnace aqueous property improver in the paper industry, or a filler retention agent. Relating to a manufacturing method.

[Conventional technology and its problems]

It is known from JP-A-5R-23ROY that water-soluble polyvinylamine can be obtained by hydrolyzing a polymer obtained by radical polymerization of N-vinylformamide.

Polyvinylamine with good water solubility can be obtained by basic hydrolysis after the N-vinylformamide polymer obtained by polymerization of N-vinylformamide is purified using a hydrophilic solvent such as methanol. When hydrolyzed, a crosslinking reaction occurs as the reaction progresses, producing a water-insoluble polymer and coloring the polymer brown.

The reason for this is not necessarily clear, but impurities contained in the M-vinylformamide polymer decompose under basic conditions to produce acetaldehyde, which undergoes a crosslinking reaction with polyvinylamine produced by hydrolysis of the polymer. It is presumed that the purpose was to cause trouble.

Purifying the N-vinylformamide polymer as described above requires a large amount of precipitation solvent and washing solvent, so it is not an industrially desirable method, and high molecular weight water-soluble polyvinylamine can be obtained without purification. A method to do this has been long awaited.

[Means for solving problems]

That is, the object of the present invention is to produce an N-vinylformamide polymer obtained by polymerizing N-vinylformamide.
*The purpose is to provide a method for producing water-soluble polyvinylamine by basic hydrolysis without
This is achieved by adding ammonia, primary amines or co-class amines to N- and diN formamide polymers, followed by basic hydrolysis.

The present invention will be explained in detail below.

In the present invention, as the N-vinylformamide polymer, not only a homopolymer of N-vinylformamide but also a copolymer with other vinyl monomers can be used. As such nyl monomers, water-soluble nyl monomers are preferred, such as (meth)acrylamide, N-
Alkyl (meth)acrylamide, N,N-dialkyl (meth)acrylamide, N,N-dialkylaminoalkyl (meth)acrylamide, (meth)acrylamidoalkyltrimethylammonium salt, (meth)acrylamide alkyl/sulfonate, (meth) Acrylonitrile, (meth)acrylate, dialkylaminoalkyl (meth)acrylate, N-vinylpyrrolide 7, N-
Alkyl-N-vinylformamide, N-alkyl-N
-vinylacetamide, diallyldialkylammonium salt, vinylpyridi/, vinylimidazole, vinylbenzyl triplekylammonium salt, vinylsulfonate and the like.

The polymerization or copolymerization of N-vinylformamide can be carried out using a radical polymerization initiator, especially co-, 2'-7zobis-coamidinobronobrono or azobis-N,N'-dimethyleneisobuteramide/. Water-soluble azo compounds such as hydrochloride, sulfuric acid or acetate, or alkali metal salts or ammonium salts of Hiro', Hiro'-azobis-φ-quanovaleric acid, based on the monomer, / 00 to / 0000 ppm
, preferably using j 00 to j 000 ppm, 3
It is carried out at a temperature of 0 to IOθ°C, preferably 0 to 20°C.

The type of polymerization is not particularly limited, and polymerization may be carried out in a solvent that dissolves the polymer to obtain a polymer solution or precipitate, or polymerization may be carried out using an aqueous monomer solution having a weight of about -00 weight or less. How to obtain an aqueous polymer solution, about 20-? jiii
A method of polymerizing using a highly concentrated aqueous solution of a monomer to obtain a water-containing solid polymer; a method of obtaining a polymer dispersion by suspending a highly concentrated aqueous monomer solution in an organic solvent and polymerizing it; The method or bulk polymerization method can be selected as appropriate.

The present invention is applied to the basic hydrolysis of the N-vinylformamide polymer thus obtained, and is particularly effective in hydrolyzing high molecular weight polymers. This is remarkable when applied to the hydrolysis of polymers whose viscosity (measured in water at a polymer concentration of 0./f/dA) is 3 or more.

By adding ammonia, a 7th-class amine, or a secondary amine to an N-vinylformamide polymer and then performing basic hydrolysis, crosslinking reaction during the hydrolysis reaction can be avoided and coloring of the polymer can also be prevented. . It is preferable to use a lower amine as the 1R or secondary amine,
Examples include methylamine, ethylamine, n-butylamine, ethanolamine, ethylenediamine, diethylenetriamine, dimethylamine, diethylamine, jetanolamine, N-methylethanolamine, and morpholine. These ammonia and amines are usually added to the N-vinylformamide polymer in the form of an aqueous solution or dissolved in a suitable solvent, but ammonia and amines with a low boiling point are added in the form of a gas to the aqueous solution or dispersion of the polymer. You can also. The amount of ammonia, primary amine, or primary amine added is within the range of 0.00/~l equivalent, preferably 0.0/~0.2 equivalent, based on the amide group of the N-vinylformamide polymer. is selected. The addition time may be before the basic hydrolysis of the polymer substantially starts, but after addition, the strong basic substance should be added as a hydrolysis catalyst after being held at 1o-to℃ for 10-200 minutes. is preferred.

Examples of the strong basic substance include alkali metal hydroxides, alkaline earth metal hydroxides, and primary ammonium hydroxide, with sodium hydroxide and potassium hydroxide being particularly preferred. These strongly basic substances are usually! N as an aqueous solution in the range of weight % to saturation concentration.
- Vinylformamide polymer 711 [, N-vinylformamide polymer hydrated solid or N-vinylformamide polymer is added to the dispersion medium in which it is dispersed, and
The hydrolysis reaction is carried out at oo<0>C, preferably from 50 to 100[deg.]C. The amount of strong basic substance used is usually 3 times the amide group to be hydrolyzed in order to obtain the desired hydrolysis rate, and when obtaining a hydrolysis rate of to% or less,は／ −／, にだいだう is appropriate. In the present invention, water-soluble polyvinylamine having an arbitrary hydrolysis rate can be obtained by appropriately adjusting the conditions, mainly the amount of the strong basic substance used. Further, if desired, after the basic hydrolysis is completed, it can be neutralized with an acid to obtain a water-soluble polyvinylamine salt.

〔Example〕

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 departs from the gist thereof.

Comparative Examples/~Co Examples/~6 N-vinyl synthesized by thermal decomposition of KN-(α-methoxyethyl)formamide Formamide! Jjt, demineralized water tys, riV and 10M
Negative λ, λ'-azobis-2-amidinopropane cohydrochloride aqueous solution/,! 1 was introduced, and polymerization was carried out for 7 hours on a RO'R while stirring under a nitrogen gas stream. The amounts of N-vinylformamide and Bl-(α-methoxyethyl)formamide contained in the product were 0.3% and 0.1%, respectively, based on the weight of the aqueous polymer solution. The polymer was dissolved in normal saline at a concentration of o, it/dt, and the reduced viscosity measured at 25° C. using an Ostwald viscometer was ηBT) 10−4 jl. Desalinated water A & 19 was added to the obtained aqueous polymer solution, stirred and diluted uniformly, and then the aqueous polymer solution λotsr was placed in a 3-Solo flask equipped with a stirrer, a cooling tube, and a thermometer. Next, add the types and amounts of additives shown in Table 1 and heat at 0°C.
After stirring for 0 minutes, λoz amount of sodium hydroxide aqueous solution Jj
Immediately after adding f, the temperature was raised and hydrolysis was carried out at 7r°C for 7 hours. After cooling, the pH of the product was adjusted to 7. Adjusted to OK.

The results are shown in Table 7.

The hydrolysis rate was calculated from the colloid titration value of an aqueous solution of the product using a polyvinyl potassium sulfate aqueous solution of normal l/≠00 under pHJ conditions using toluidine blue as an indicator.

*/) Insoluble in water and cannot be neutralized with hydrochloric acid.

*λ) Aqueous ammonia was added after adding sodium hydroxide.

*3) Thickened during hydrolysis reaction.

〔Effect of the invention〕

According to the present invention, it is possible to obtain a high molecular weight water-soluble polyvinylamine by cyclic hydrolysis without purifying an N-vinylformamide polymer obtained by polymerizing N-vinylformamide. High-quality water-soluble polyvinylamine can be produced without hydrolysis under strongly acidic conditions, which is problematic due to the material of the reactor.

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

Claims (1)

[Claims] (1) A method for producing water-soluble polyvinylamine, which comprises adding ammonia, a primary amine or a secondary amine to an N-vinylformamide polymer, and then subjecting it to basic hydrolysis.