JPS6045207B2 - Production method of water-soluble polycarboxylate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a water-soluble polycarphonate, and provides a method for producing a highly polymerized product of the above-mentioned polymer with less insoluble matter by economically advantageous and easy production operations. It is something to do.

Aqueous solution polymerization and bar polymerization of sodium acrylate are known as methods for obtaining water-soluble polycarboxylate salts, such as sodium polyacrylate, but it is difficult to obtain a product with a high degree of polymerization, and the monomer The solubility in water is at most 40
% (same below weight %), polymerization due to low concentration is unavoidable, and when obtaining a powder product, in addition to economic disadvantage due to subsequent drying, there are many troubles due to the formation of insoluble matter.
On the other hand, a method of polymerizing an aqueous solution of sodium acrylate in a water-soluble organic solvent has been carried out, but the polymer may be cake-like and adhere to the reactor wall, or the polymer may have a high water content and many insoluble matter. There are some drawbacks.

It has also been proposed to prepare the entire amount of acrylic acid in a water-soluble organic solvent and add an alkali to carry out the acid neutralization reaction all at once, but the polymerization becomes cake-like and causes damage to the walls of the reactor. However, there still remain disadvantages such as adhesion to stirring blades and difficulty in manufacturing operations. The present inventors have conducted extensive research in an attempt to solve the above-mentioned drawbacks of producing water-soluble polycarboxylic acid salts and to obtain the desired product using an extremely advantageous method. A neutralization reaction is carried out during the polymerization by sequentially introducing a saturated carboxylic acid or a monomer mixture containing this as a main component and other copolymerizable vinyl compounds, and at the same time, alkali is sequentially introduced, thereby causing a reaction. The present inventors have discovered that water-soluble polycarboxylic acid salts can be produced easily and economically while minimizing the water content of the system, leading to the completion of the present invention. As mentioned above, the present invention involves simultaneous polymerization of an α,β monounsaturated carboxylic acid monomer or a monomer mixture mainly composed of this in a water-soluble organic solvent, and alkali neutralization. In this case, the monomers are added to the solvent and the alkali solution is added for neutralization, rather than the so-called batch preparation in which they are added all at once prior to polymerization. It is necessary to continuously or intermittently add the so-called sequential addition during the neutralization reaction.

Moderate α,β monounsaturated carboxylic acid and its neutralized α
, a metal salt of a β-monounsaturated carboxylic acid, or . There is a significant difference in solubility in water-soluble organic solvents from ammonium salts, and in general, the solubility of α,β-monounsaturated carboxylic acids in water-soluble organic solvents is said to range from high concentration to infinite. When neutralized with ammonia, it becomes insoluble or dissolves only in a trace amount, and in this case, the solubility can be improved by adding an appropriate amount of water to the water-soluble organic solvent.

Furthermore, there is also a difference in solubility in a mixture of an appropriate amount of water and a water-soluble organic solvent between monovalent alkali metal or ammonium salt monomers of α,β monounsaturated carboxylic acids and their polymers. However, the solubility of the polymer is much lower than that of the monomer, and the polymer can be precipitated by adjusting the mixing ratio of water.

The above-mentioned sequential addition of the present invention cleverly utilizes this knowledge.In the case of the above-mentioned one-time injection, since the ratio of water to polymer is large in the early stage of polymerization, it becomes cake-like and forms on the walls of the equipment, stirring blades, etc. However, according to the method of the present invention, a small amount of the monomer is added to a water-soluble organic solvent, and at the same time, a small amount of water or an alkali dissolved in the water-containing organic solvent is added concurrently with the addition of the monomer. By adding small amounts of water and controlling the rate of addition, water is uniformly supplied in small amounts, and the polymer is precipitated in the form of a slurry, eliminating the troublesome problems mentioned above.

Such sequential addition makes it easy to adjust the amount of water supplied, and by properly adjusting the amount of water, the monomer can be sufficiently dissolved. In addition, it is possible to ensure the precipitation of the polymer, and in particular, when manufacturing powder products, conventionally, polymerization with a low monomer concentration of 40% or less is forced, and there is a great economic disadvantage due to drying. As mentioned above, according to the method of the present invention, the amount of precipitated polymer can be easily reduced to 40% or more by using a solid-liquid separator such as a centrifuge or filter press, which is economical in this respect. The benefits are extremely large. The amount of water in the method of the present invention may be in the range of 10 to 250% of the amount of salt monomer produced by alkali neutralization, including water for adjusting the concentration of alkali and water produced by neutralization. Desirably, if it is less than 10%, the solubility of the salt monomer itself in water-soluble organic solvents will be poor, and if it exceeds 250%, excess water will tend to form a cake-like polymer, which will lead to the above-mentioned troubles. Therefore 10 to 250%
It is desirable to select optimal conditions within the range of . The amount of the water-soluble organic solvent is preferably 30 to 60% based on the total amount of the solvent, water, and salt monomer. Examples of α,β monounsaturated carboxylic acids applicable to the method of the present invention include acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, maleic acid, fumaric acid, glutaconic acid, itaconic acid, and sorpic acid. Examples of alkaline substances for neutralization include sodium hydroxide, potassium hydroxide, soda carbonate, ammonia, etc., and water-soluble organic solvents include solvents that are insoluble to the produced polymer. Examples include alcohols such as methanol, ethanol, propanol, isopropanol, and butanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, dimethylformamide, and ethyl acetate.

In the neutralization polymerization reaction of the present invention, if the neutralization reaction is biased toward the extreme alkaline side, the polymerization reaction proceeding at the same time tends to become non-uniform, and the polymerization reaction at the extremely acidic side tends to cause the reaction of the produced polymer to become uneven. This may cause adhesion to walls, stirrers, etc., and may also cause problems in terms of physical properties such as agglomeration, resulting in poor yield and formation of water-insoluble substances.

Therefore, it is desirable to maintain the degree of neutralization in the range of approximately 30 to 100n101% of the α,β-monounsaturated carbonic acid during the polymerization reaction.

The polymerization is carried out in the presence of a conventional polymerization initiator, and it is desirable that the polymerization initiator be dissolved in a water-soluble organic solvent in advance. Next, by simultaneously adding a polyfunctional monomer sequentially during the neutralization polymerization reaction of the present invention, a moderately crosslinked water-soluble polymer is obtained, and a polymer having quasi-plastic flow characteristics is obtained. I can do it. The polymer having quasi-plastic flow characteristics is gel-like, has a constant crosslink density, and is relatively stable against heat and strong alkalis. Most polyfunctional monomers used for this purpose are compounds that have two or more active carbon-carbon double bonds in the same molecule and are soluble in water-soluble organic solvents. ,
Specifically, (1) acrylates and methacrylates of polyhydric alcohols such as butanediol diacrylate, butanetriol trimethacrylate, butanediol dimethacrylate, and diethylene glycol diacrylate, (2) Shugar allyl ether, maltose allyl ether, and lacquer. Polyhydric alcohol allyl ethers such as toz allyl ether, butanediol allyl ether, butanetriol triallyl ether, and glycerin triallyl ether; (3) glyogyzar alkenyl compounds such as glyogyzaal tetraallyl ether and glyogyzaal tetramethallyl ether; .

(4) Aluminum of acrylic acid or methacrylic acid,
Polyvalent metal salts such as calcium, magnesium or iron salts.

(5) Other examples include divinylsulfone, divinylbenzene, triallylamine, methylenebisacrylamide, and the like.

The general range of use of these polyfunctional monomers is as follows:
It is approximately 0.5 to 30% of the mixed monomer containing alpha, beta monounsaturated carboxylic acid or other copolymerizable vinyl compounds mainly composed of this, but it is There are particularly optimum ranges for the amount added depending on the type, and the main ones are as follows.

That is, (a) 3 to 15% of the acrylate and methacrylate of the polyhydric alcohol shown in (1) above (b) 0.5 to 15% of the polyhydric alcohol allyl ether shown in (2)
(c) 0.5 to 10% of the glyogyzal alkenyl compound shown in (3) (d) 2 to 30% of the polyvalent metal salt of acrylic acid or methacrylic acid shown in (4). If too little is used, the quasi-plastic flow properties due to crosslinking at low viscosity will be lost, resulting in properties similar to those without polyfunctional monomers, while if too much is used, the crosslinking density will decrease. increases, making it difficult to dissolve in water,
It shows a tendency to produce a lot of insoluble matter.

The salt polymer obtained by the present invention can be used as a thickener or dispersant in hand creams, hair creams, shaving creams, cleansing creams, etc. in the cosmetics industry, and as a stabilizer in lotion baby oil, etc., in the pharmaceutical industry. Aluminum hydroxide,
As a solid suspension stabilizer for magnesium hydroxide, gypsum, etc.
As a sizing agent for warps, printing, washing, etc. in the textile industry, as a thickening agent for latex for flocking, as a binder for non-woven fabrics, as a dispersant for glass fibers, as a fiber wall sizing agent, special coating material, and spatula-coated walls in the construction industry. As a thickener for lumber, plywood adhesives, plaster cement, rubber cement, polyurethane cement, vinyl chloride resin cement, ricin spraying materials, emulsion stabilizers, suspension stabilizers, etc., as a thickener for wallpaper removers, etc.
As an additive for fabric excipients, refractory bricks, and refractory mortars in the ceramic industry, as a thickener for water-soluble paints and emulsion paints in the paint industry, and as a pigment dispersant for mold paints.
As a thickener and extensibility improver for tar asphalt emulsions in the civil engineering industry, as a water-stop gelling agent, as a spreading agent or emulsion dispersion stabilizer for agricultural chemicals in the agricultural industry, as a thickening pigment dispersant for water-based printing inks in the printing ink industry. As a thickener for various latex emulsions in the rubber and resin industries, as a thickener for cold-vulcanizable silicone rubber pastes, as a thickener for liquid detergents and Jumpu in the detergent industry, and as an excipient for bar soaps, as a fire extinguishing liquid. It is useful as a thickener, a foam stabilizer, and as a thickener, gelling agent, dispersant, and adhesive in many other fields.

In particular, in the case of salt polymers crosslinked using polyfunctional monomers, the aqueous solution is a transparent gel-like high viscosity quasi-plastic fluid, and polyfunctional monomers are not used. Although it has a significantly higher viscosity than the obtained polymer, it has excellent fluidity due to low stress and high shaping power, and can be used in the various applications mentioned above in a wide concentration range. Examples and comparative examples are listed and explained below, but in these, 1 part and 1% are based on weight, and the physical property measurement methods used in these are as follows. It is.

(1) Viscosity, B type viscometer 25°C (2) Flow characteristics, visual observation.

Example 1 18 parts of acrylic acid and 20.8 parts of a 48% caustic soda aqueous solution were added to 6 parts of isopropanol and 0.1 parts of benzoyl peroxide.
The mixture was continuously added to the solution in which 1 part was dissolved at 80°C over 3 hours.

After aging for 1 hour, it was cooled and the solid and liquid were separated.

Sodium polyacrylate was successively precipitated in the form of powder during 3 hours of continuous addition, and finally became a slurry. The separated powder was dried at 150° C. for 1 hour, resulting in a polymer powder of over 98%. It should be noted that there was no problem of the polymer adhering to the walls of the vessel during the polymerization operation. Example 2 21.5 parts of methacrylic acid and 28 parts of a 50% methanol solution of caustic potassium were continuously added to a solution of 0.05 part of azobisisobutyronitrile dissolved in methanol at 65°C over 5 hours. added to.

Powder of polypotassium methacrylate is successively precipitated during polymerization,
No polymer adhesion problems occurred. Comparative Example 1 When each raw material was added to a solvent at once and polymerized using the same recipe as in Example 1, bumping of the reaction solution occurred due to insufficient heat removal, and a rice cake-like polymer formed on the wall of the reaction vessel and the stirring blade. It was attached to.

Example 3 56.9k9 methanol in a 0.2d autoclave
Add 0.1k9 of benzoyl peroxide powder to this and separately add 20k of acrylic acid while maintaining the temperature at 65℃.
9 and glycerin triarylether 0.3k9 and a 48% sodium hydroxide aqueous solution 23.1k9 were prepared, each was divided into two powders, and added to the methanol at intervals of one powder to carry out a neutralization polymerization reaction. When carried out, the neutralization polymerization reaction was completed in about 9 hours.

The polymer mainly composed of sodium polyacrylate produced in the methanol water bath had fine particles and formed a slurry. This slurry polymer was separated using a centrifuge, and the polymer was obtained as a 45 to 55% solid mass. The mass was then dried at 100 to 120°C in a 20 to 4-powder ventilation dryer to obtain a white fine powder polymer with a volatile content of 2% or less, with a yield of about 95%. This polymer can be used to obtain a transparent, high-viscosity quasi-plastic liquid simply by dissolving it in water without any complicated operations such as dispersion and swelling in water or neutralization reaction with an alkali substance, for example, 0.5%. The aqueous solution of was 7,00 ('PS) at 25°C.

Comparative Example 2 In Example 3, 20k9 of acrylic acid, 0.3k9 of glycerin triallyl ether, and 23.1kg of 48% sodium hydroxide were added all at once to the reactor.

As a result, due to the rapid neutralization reaction, heat removal cannot be carried out smoothly, the reaction solution bumps, and furthermore, even during polymerization, not only can only a product with a significant amount of unreacted monomer remain, but also the polymer The adhesion to the reactor walls and stirring blades was so severe that it could not be used as an industrial production method. Example 4 In the autoclave used in Example 3, 66 kg of ethanol and 0.3 kg of azobisisobutyronitrile were added.
of acnolylic acid while maintaining the temperature at 75°C.
8k9, styrene 2k9, magnesium acrylate 2k
9 and 7.5k9 of 28% ammonia water were continuously added to the ethanol bath, and the polymerization reaction was simultaneously carried out while neutralizing acrylic acid with ammonia.

The rate of addition of the mixed monomer and ammonia was adjusted so that the neutralization rate of acrylic acid in the reaction system was 65%, and the entire amount was added continuously over 6 hours. Then, when the polymerization reaction was continued for 2 hours, about 99% of the reaction mixture was converted into a polymer, and a milky white fine particle-dispersed slurry polymerization liquid was obtained. This is immediately cooled, the polymerized product is made into a mass using a centrifuge, and then dried for 2 hours in a tray dryer at 90 to 100°C, resulting in a high yield of 97% and a white fine powder with a volatile content of less than 1%. A powdered polymer was obtained. This polymer mainly composed of ammonium polyacrylate has a 0.2% aqueous solution viscosity of 1,500 CPS/2
It became a transparent quasi-plastic flowing liquid at 5°C. Example 50.2m
Add 56.9 kg of methanol to the autoclave in step 3, dissolve 0.1k9 of benzoyl peroxide powder in it, and make 65
While maintaining the temperature at ℃, separately prepare a 48% aqueous sodium hydroxide solution 23.1k9 and a mixed monomer of acrylic acid and glyogysal tetraallyl ether shown in Table 1, and add this 48% aqueous sodium hydroxide solution. Each of the mixed monomers was divided into 2 parts and sequentially added to the methanol at intervals of 1 part to carry out neutralization and polymerization reactions.

As a result, the reaction was completed in about 9 hours, and a polymer containing sodium polyacrylate as a main component was obtained in the form of a slurry.
This slurry polymer is separated by centrifuge,
The polymer concentration was obtained as a solid mass of 45-55%.

The mixture was then dried in a ventilation dryer at 100 to 120°C for 30 to 50 minutes to obtain a white fine powder polymer with a volatile content of 2% or less in high yield. A 1% aqueous solution of this fine white powder had the results shown in Table 1 in terms of viscosity and flow characteristics. Example 6 Methanol 56.9k9 in a 0.2 world autoclave,
Add 0.1 kg of benzoyl peroxide powder, and while maintaining the temperature at 65°C, separately add 23.1 k9 of a 48% aqueous sodium hydroxide solution and the mixed monomers of acrylic acid and acrylic acid sugar ester shown in Table 2. Prepare this for 100y
/T$t into the methanol bath continuously.

Claims (1)

[Claims] 1. A monomer mixture containing α,β-unsaturated carboxylic acid or other copolymerizable vinyl compounds mainly composed of α,β-unsaturated carboxylic acid is introduced into a water-soluble organic solvent and polymerized. 2. A method for producing a water-soluble polycarboxylic acid, which is characterized by simultaneously carrying out a neutralization reaction during polymerization by sequentially adding alkali. 2. Polymerization is carried out by sequentially adding a monomer mixture of α,β-unsaturated carboxylic acid or other copolymerizable vinyl compounds containing this and a polyfunctional monomer into a water-soluble organic solvent. A method for producing a water-soluble polycarboxylic acid salt, which is characterized in that, at the same time, a neutralization reaction is carried out during polymerization by sequentially adding alkali. 3. As a polyfunctional monomer, one or more selected from glyogyzal alkenyl compounds are mixed with α,β-unsaturated carboxylic acid or other copolymerizable vinyl compounds mainly composed of this. 0.5 to 10% by weight based on the amount
The manufacturing method according to claim 2, which is used within the scope of claim 2. 4. As a polyfunctional monomer, one or more selected from acrylates and methacrylates of polyhydric alcohols are combined with α,β-unsaturated carboxylic acids, or other copolymerizable vinyl compounds mainly containing this. 3 for monomers mixed with
The manufacturing method according to claim 2, wherein the amount is used in the range of 15% by weight. 5. As a polyfunctional monomer, one or more polyhydric alcohol allyl ethers are combined with α,β-unsaturated carboxylic acid,
or the manufacturing method according to claim 2, in which the monomer is used in an amount of 0.5 to 15% by weight based on the mixed monomer with other copolymerizable vinyl compounds. 6 As a polyfunctional monomer, one or more polyvalent metal salts of acrylic acid, methacrylic acid and methacrylic acid are used as α, β
- 2 to 30% of the monomer mixture with unsaturated carboxylic acid or other copolymerizable vinyl compounds based on unsaturated carboxylic acid;
The manufacturing method according to claim 2, wherein the amount is used in a range of % by weight.