JPS6125733B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a powdered crosslinked carboxyl group-containing copolymer suitable for use as a thickening agent for various aqueous solutions. The first industrially produced synthetic thickeners were obtained by direct polymerization of acrylic acid and methacrylic acid, followed by a neutralization reaction, or alternatively by polymerization of polymethyl acrylate solution or polyacrylic acid. They were polyacrylic acid salts or polymethacrylic acid salts obtained by hydrolyzing an ethyl solution or polyacrylonitrile powder. The conventional thickeners thus obtained are highly viscous solutions that require dilution to a concentration of 5 to 10% to handle them, and furthermore, it is difficult to dry the products. Therefore, the thickening agent had to be stored at moderate concentrations, which is quite uneconomical from an industrial point of view. Subsequently, more or less reticulated aqueous emulsions of copolymers of acrylic acid and acrylic esters were developed, and these improved copolymer products
Thickening can be achieved using the form of an emulsion containing 40% to 40% solids, but it is difficult to dry on an industrial scale, and although it has a high viscosity when dissolved in water, it cannot be used as a thickening agent. It was not of a satisfactory nature. The present invention essentially relates to a process for the preparation of a new industrial product which is almost 100% dry solids, can also be obtained in powder form, and has properties suitable as a thickening agent to give a concentrated liquid of low concentration and high viscosity. It is something. That is, the present invention provides carboxyl type monomers and general formula

[Formula] or

[Formula] (In the formula, R ¹ represents hydrogen or an alkyl group. R ² is an x-valent organic aromatic compound, organic alicyclic compound, organic heterocyclic compound, or organic aliphatic hydrocarbon compound, or the formula

[Formula] (In the formula, R ³ represents hydrogen or an alkyl group, and n is a positive integer satisfying 0<n≦500.)
x represents a positive integer from 2 to 8. ) is preferably copolymerized and crosslinked in an aqueous solution and used as it is, or more preferably, in a medium that dissolves both of these monomers but does not dissolve the resulting crosslinked copolymer, for example, known By copolymerizing and crosslinking using a polymerization initiator, a crosslinked copolymer having networked carboxyl groups is produced. After neutralization, the product has properties suitable as a thickening agent, giving very high viscosity concentrates at low concentrations. General formula () or () used in the present invention
For example, the corresponding polyhydric phenol,
Polyvalent hydroxy organic aromatic compounds such as polyvalent naphthol, polyvalent hydroxy organic alicyclic compounds such as polyvalent cyclohexanol, polyvalent hydroxy organic heterocyclic compounds such as polyvalent hydroxyquinoline, ethylene glycol, Polyvalent hydroxy organic aliphatic hydrocarbon compounds such as propylene glycol and tetramethylene glycol, polyalkylene glycol compounds such as polyethylene glycol and polypropylene glycol, and allylcarboxylic acid, methallylcarboxylic acid, 2-ethyl-1-butenoic acid, etc. , or polyvalent carboxy organic aromatic compounds such as phthalic acid, trimellitic acid, benzene-1,2,4,5-tetracarboxylic acid, polyvalent carboxy organic alicyclic compounds such as hexahydrophthalic acid,
Polyvalent carboxy organic heterocyclic compounds such as dicarboxypyridine, polyvalent carboxy organic aliphatic hydrocarbon compounds such as glutaric acid, adipic acid, malonic acid, polyethylene oxide dicarboxylic acid, polypropylene oxide dicarboxylic acid, etc., allyl alcohol, methallyl It is obtained by reacting alcohol, 2-ethylpropylene alcohol, etc. In the present invention, one or a mixture of two or more compounds selected from the group of compounds represented by the general formula () or () is used. The compounds represented by these general formulas () or () can also be used as crosslinking agents for monomers having other unsaturated bonds, and are particularly useful as crosslinking agents for water-soluble monomers such as acrylamide and vinylpyrrolidone. When used, a highly viscous crosslinked product suitable for use as a collector, for example, can be obtained. In order to obtain the desired thickening properties of the crosslinked copolymer produced, the amount of the compound represented by the general formula () or () varies depending on the type of these compounds, but usually the monomer Approximately 0.1% to 30% of the total amount
%, preferably 0.5% to 10%. The present invention is characterized by the use of a compound represented by the general formula () or () as a crosslinking agent, which allows conventional thickening agents such as allyl sucrose, trimethylolpropane triacrylate or Produces a better thickening agent that provides a thicker liquid with a higher viscosity than conventional copolymers of polyfunctional acrylic monomers such as pentaerythritte tetramethacrylate and α,β-unsaturated acids. You can. Carboxyl type monomers useful in the present invention include:
an olefinically unsaturated carboxylic acid containing at least one active carbon-carbon olefinic double bond and at least one carboxyl group;
In other words, it is an easily polymerizable acid in which the olefinic double bond is present at the α or β position relative to the carboxyl group in the monomer molecule, or as a terminal methylene group, such as acrylic acid. , methacrylic acid, itaconic acid, chloroacrylic acid, cyanoacrylic acid, α-phenylacrylic acid, α-benzylacrylic acid, crotonic acid, maleic acid, fumaric acid, sorbic acid and other olefinically unsaturated carboxylic acids. It is one or a mixture of two or more selected from the group. The production method of the present invention is preferably carried out by mixing and dissolving a compound represented by the general formula () or () as a crosslinking agent and an olefinic unsaturated carboxylic acid, and carrying out the process in a solvent that does not dissolve the resulting copolymer. ,
For example, solvents such as toluene, benzene, n-hexane, ethyl acetate, and cyclohexane are used. Further, as the polymerization initiator used in this method, azo-based, peroxide-based, redox-based radical polymerization initiators, etc. can be used without any problem. For example, azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,
4-dimethyl-4-methoxyvaleronitrile),
Benzoyl peroxide, cumene hydroperoxide, tertiary butyl hydroperoxide,
These include persulfates, combinations of persulfates and percarbonates, combinations of persulfates and sulfites, and the like. Of course, the polymerization temperature varies depending on the type of catalyst used, the type of monomer, etc., but generally it is 30°C.
Preferably, the temperature is between 90°C and 90°C. After the polymerization reaction is completed, the precipitate is filtered and dried, and the carboxyl groups of the crosslinked copolymer are neutralized to obtain the maximum viscosity in water at a neutral or basic pH value. Bases commonly used to neutralize carboxyl groups include inorganic bases such as sodium hydroxide, ammonium hydroxide, potassium hydroxide, sodium carbonate, and potassium bicarbonate, and organic bases such as triethanolamine, dodecylamine, and triethylamine. A base is used. The polymerized and crosslinked carboxyl monomer obtained by this method is used as a various thickening agent for thickening cosmetic creams, paints, sizing baths, etc. The amount of said polymer incorporated for thickening purposes will vary depending on the particular composition of the medium to be thickened, but generally an amount of 1% or less is sufficient to obtain the desired viscosity. The concentrated liquid made using the polymerized cross-linked product of carboxyl type monomers produced by this method has a higher viscosity than conventional products, so even when used in small amounts, it exhibits considerable thickening power. It is an extremely useful thickening agent. The present invention will be further explained by referring to Reference Examples and Examples below. In the examples, parts expressed are parts by weight. Example 1 59 parts of acrylic acid, 540 parts of benzene, 0.3 parts of azobisisobutyronitrile, and 2 parts of diallyl adipate were introduced into a reaction vessel equipped with a thermometer, a stirring device, and a nitrogen introduction tube, and the mixture was heated at 50°C. 1.5 hours, 70℃
React for 2 hours under nitrogen. The mixture was cooled, filtered and dried to obtain 60.2 parts of a white, low density fine powder. Disperse 1 part of this powder in 500 parts to make a 0.2% solution, neutralize with 10% caustic soda aqueous solution, and dissolve at pH 7.
CPS viscosity and yield value were measured. For comparison, the results obtained using a conventional crosslinking agent are also shown. *Conducted at 25℃ using a B8H type rotational viscometer. *Yield value was calculated using the following formula. Yield value (dyne/cm ² ) = (apparent viscosity at 0.5 rpm -
Apparent viscosity at 1.0 rpm) x 1/100

[Table] Example 2 Using the same equipment as in Example 1, 59 parts of acrylic acid,
540 parts of cyclohexane, 2,2'-azobis (2,
0.25 part of 4-dimethylvaleronitrile) and the crosslinking agent shown in the table below were introduced, and the mixture was heated at 50°C for 30 minutes and then at 70°C.
React under nitrogen for 1.5 h. The mixture was cooled, filtered and dried to obtain a white, low density powder. One part of this powder was dispersed in 500 parts of water, neutralized with a 0.2% solution and a 20% aqueous sodium carbonate solution, and the CPS viscosity at pH 7 was measured.

[Table] Example 3 Using the same equipment as in Example 1, 59 parts of acrylic acid,
540 parts of n-hexane, benzoyl peroxide
0.3 parts of the crosslinking agent shown in the table below was introduced and the mixture was heated to 50
C. for 1 hour and 70.degree. C. for 1 hour under nitrogen.
The mixture was cooled, filtered and dried to obtain a white, low density powder. Disperse 1 part of this powder in 500 parts and mix with 0.2% solution and 10% sodium hydroxide aqueous solution at pH 7.
CPS viscosity was measured.

[Table] Example 4 Methacrylic acid 67 using the same equipment as Example 1
1 part, 600 parts of ethyl acetate, 0.3 part of azobisisobutyronitrile, and diallyl adipate in various proportions shown in the table below, and the mixture was heated at 50°C for 1.5 hours.
React at 70°C for 1 hour under nitrogen. The mixture was cooled, filtered and dried to obtain a white, low density powder. This powder 3
1 part was dispersed in 500 parts of water to make a 0.6% solution, which was neutralized with a 10% aqueous solution of caustic soda, and the CPS viscosity at pH 7 was measured.

【table】

【table】

Claims (1)

[Claims] 1. When polymerizing and crosslinking olefinic unsaturated carboxylic acids, a crosslinking agent of the general formula [Formula] or [Formula] (wherein R ¹ represents hydrogen or an alkyl group, R ² represents an x-valent group) is used as a crosslinking agent. An organic aromatic compound, organic alicyclic compound, organic heterocyclic compound, or organic aliphatic hydrocarbon compound of the formula [Formula] (wherein R ³ represents hydrogen or an alkyl group, and n represents 0<n≦500 x is a positive integer of 2 to 8. x is a positive integer of 2 to 8. manufacturing method.