JPS5815510A - Production of crosslinked copolymer - Google Patents

Abstract

PURPOSE:To obtain a crosslinked copolymer useful in the production of poultice compositions, by introducing a water-soluble portion into a copolymer, pH<=8, prepared by polymerizing a monomer mixture consisting of an alpha,beta-unsaturated carboxylic acid and its alkali metal salt in the presence of a polyfunctional crosslinking agent. CONSTITUTION:The titled crosslinked copolymer is prepared by polymerizing a monomer mixture consisting of an alpha,beta-unsaturated carboxylic acid of formulaI, wherein R is H, COOH or COOX, R1 is H, CH3, CH2COOH or CH2COOX and X and X1 are each an alkali metal or a derivative thereof and an alkali metal salt of an alpha,beta-unsaturated carboxylic acid of formula II, wherein R2 is H, COOH or COOX3, R3 is H, CH3, CH2COOH or CH2COOX4 and X2, X3 and X4 are each an alkali metal, in the presence of 10<-3>-1mol%, based on the monomer, polyfunctional crosslinking agent and introducing 10-70wt% water-soluble portion into the resulting copolymer, pH<=8, (pH control can be made by selecting monomer blending ratios).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a crosslinked polycarboxylic acid copolymer having a water-soluble portion of 10 to 70% by weight. Conventionally, polycarboxylic acid polymers have been used for various purposes, but
The present manufacturing method is particularly intended for application to cloth agent compositions.

The so-called tofu agent is a slurry consisting of a powder base material such as kaolin, bentonite, zinc oxide, etc., a wetting agent such as glycerin, propylene glycol 2 tulpitutol, and water, and a volatile medicinal agent such as menthol, camphor, methyl salicylate, etc. The composition is prepared by spreading and coating a cloth such as flannel or lint cloth, and then attaching a releasable protective film such as polyethylene/film to the drug surface.

This tofu agent is effective in eliminating inflammation and pain relief for fractures, bruises, sprains, stiff shoulders, etc. When used, this patch can be applied immediately to the affected area after peeling off the protective film from the drug side.The action of the main ingredient and water gives a cooling sensation to the skin surface, and the evaporation of water promotes fever reduction in the affected area. Overall, it is expected to have therapeutic effects such as anti-inflammatory and analgesic effects.

The quality of the tomoe agent composition is that it has good miscibility during kneading, is flexible and adheres well to the skin, has good water retention and remains moist on the skin for a long time, and has a firm overall appearance. Conventionally, in order to give the above-mentioned performance to the dressing composition, sodium polyacrylate was added as an active ingredient, and sodium polyacrylate was combined with carboxymethyl cellulose, gelatin, sodium alginate, xanthan gum, etc., and a pH adjuster was added. Attempts have been made to mix them together, but nothing satisfactory has yet been achieved.

The present inventors have discovered that water-soluble polymers are effective in terms of miscibility and water retention as active ingredients that enhance the miscibility and water retention of a dressing composition and provide stability over time to medicinal ingredients. Focusing on the effectiveness of cross-linked polymers and the effectiveness of neutral polymers in maintaining the stability of medicinal ingredients over time, we conducted various research into methods for producing polymers that have all of these properties. The present invention was completed based on the knowledge that it is possible to produce a polymer having high performance as a drapery composition by elucidating the n-bridge hexamer polymerized under the following conditions. That is, the present invention has the following formula:
or 0H2000Xle. In addition, X and xl represent an alkali metal, α/β-unsaturated carboxylic acid or its derivative represented by 0 and the general formula (wherein, R2 represents 11.000 H or 000 X5, R6 represents ■), OH5 , OH2000H or Cl
−12a o ox4 is shown. In addition, x2. x5
and X4 represents an alkali metal, so a mixed monomer prepared from the alkali metal salt of the α/β-unsaturated carboxylic acid represented by
Examples of the α/β-unsaturated carboxylic acid represented by the general formula (1) or its derivative used in the present invention include acrylic acid, methacrylic acid, (5) Fumaric acid, maleic acid, itaconic acid and other monounsaturated carboxylic acids or derivatives thereof having the general formula 1%
You may use a mixture of more than one species.

In addition, examples of the alkali metal salts of α/β-unsaturated carboxylic acids represented by the general formula (2) include sodium acrylate, potassium acrylate, lithium acrylate, sodium methacrylate, potassium methacrylate, and methacrylic acid. Examples include lithium, sodium maleate, sodium itaconate, and other substances contained in general formula (2). These alkali metal salts of α/β-unsaturated carboxylic acids may be used alone or in combination of two or more.

α/β-unsaturated carboxylic acid or its derivative and α/β-
The mixing ratio of the unsaturated carboxylic acid with the alkali metal salt is such that the monomer mixture is copolymerized in the presence of a polyfunctional crosslinking agent so that the crosslinked copolymer obtained has a pH of 8 or less. Ru. Even better 1
Or, the pH is in the range of 6 to 8 and two polymerizable double bonds (
Examples include (1) di- or polyvinyl compounds (di- or trivinylbenzene, divinyltoluene, divinylxylene, divinyl ether, divinyl keto/etc.), (i+
) Di- or poly-esters of unsaturated mono- or polycarboxylic acids and polyols [di- or tri(meth)acrylic acid esters of polyols (ethylene glycol, trimethylolpropane, glycerin, polyethylene glycol, polypropylene glycol, etc.), the above polyols and unsaturated carboxylic acid (maleic acid, etc.)], (1111 bis(meth)acrylamide (N,N'-methylenebisacrylamide, etc.),
IV polyisocyanate (TD■, IID■, MDI
etc., and a carbamyl ester obtained by the reaction of a NOO group-containing prepolymer obtained by reacting these with an active hydrogen-containing compound) and a hydroxyl group-containing monomer [a diacetate of hydroxyethyl (meth)acrylate and the above diisocyanate]. (meth)acrylic acid carbamyl ester, etc.)
, (V) di- or poly-(meth)allyl ether (polyethylene glycol diallyl ether, allylated starch, allylated cellulose, etc.) of polyol (alkylene glycol, glycerin, polyalkylene glycol, carbohydrate, etc.), (vD polycarboxylic acid) Di- or poly(meth)allyl esters (diallyl phthalate, diallyl adipate, etc.), esters of mono(meth)allyl ether of zero polyol and unsaturated carboxylic acid [polyethylene glycol monoallyl ether (meth)acrylate, etc.], etc. .

These polyfunctional crosslinkers have a 10-3
As a method for obtaining a polymerization rate of 1 molar, preferably 10-2 to 10-1 molar, any conventionally known method may be used, such as using water, methanol, ethanol, tetrahydrofuran, acetone, or a mixture thereof as a polymerization solvent. , a method of polymerization using a radical polymerization catalyst, a method of polymerization using a so-called redox catalyst that combines a persulfate and an organic amine, etc.;
It is also possible to employ a so-called water-in-oil suspension polymerization method in which an aqueous solution is suspended in an organic medium.

The polymerization temperature varies depending on the type of catalyst used, but is usually in the range of 0 to 100°C, preferably 0 to 50°C.

The reaction time is suitably 1 to 9 hours, and the reaction may be carried out either in air or under a nitrogen gas atmosphere, but it is preferable to carry out the reaction under a nitrogen gas atmosphere.

The reaction product can be obtained by directly clarifying the water-containing gel of the powder by precipitation or evaporation using a water-soluble solvent such as methanol or acetone, or by adding the recovered powder to water or water using a conventional polymer recovery method. Alternatively, it may be clarified in a swollen state in a mixture of water and a suitable water-miscible solvent.

The present invention will be explained in more detail below with reference to Examples.

Example 1 263f of a 1% aqueous solution of methylene bisacrylamide was added to a 500-monocarbon tube equipped with a nitrogen inlet tube and a thermometer. After purging with N2 for 1 hour, the mixture was kneaded in a 1-thiopersulfuric acid oven to give a clarifying effect. The water-containing gel extracted from the meat grinder was washed with a mixed water/methanol solution, dried with hot air at 120°C for a day and night, and then made into a powder.The pH of the 1% aqueous solution of the resulting powder was 6.2. . In addition, the same aqueous solution 4002 was separated using a 200-mesh wire mesh,
The gel was washed with 2,000 g of water, the remaining gel was dried, and the amount of water-soluble portion was calculated from its weight, which was 35 g based on the total weight.

Example 2 1% methylenebisacrylamide], 31 f was added. After replacing with N2, ammonium persulfate aqueous solution 2.
A polymer powder was obtained in the same manner as in Example 1 by adding 43f and 243v of a 2% aqueous sodium sulfite solution. 5 tons of this powder was swollen in 1.25 Of water and then subjected to high-speed stirring using a homomixer.

Thereafter, this liquid was poured into methanol to recover the polymer, which was again dried to form a powder.

The PI-1 of an aqueous solution of this powder was 71.

Further, the amount of water-soluble portion of this polymer was 52%.

Comparative Example 1 When polymerization was carried out under the same conditions as in Example 1 without clarification using a meat grinder, the proportion of water-soluble portion of the polymer was 3%.

Comparative Example 2 When polymerization was carried out under the same conditions as in Example 2 without high-speed stirring using a homomixer, the water-soluble portion of the polymer was 2.

Patent applicant: Showa Denko Co., Ltd. Representative Patent Attorney Sei Kikuchi

Claims (1)

[Claims] General formula % formula % (wherein R represents I(,000H or coox, R
1 is I(, OH5, OH20001-1 or 0■2c
o o Xj is shown. In each case, X and Xl represent an alkali metal. ) and the general formula % formula % (wherein ear 2 represents ■(,000H or 000
112c o o x4 is shown. Note that x2, X5 and X4 represent alkali metals. ) A mixed monomer consisting of an alkali metal salt of an α/β-unsaturated carboxylic acid represented by
l) I-18 or less polycarboxylic acid crosslinking agent obtained by polymerization in the presence of 1 mol of a polyfunctional crosslinking agent? 1 = clear coalescence, the polymer is 10-70% by weight