JP2000017026A - N-vinylcarboxamide-based crosslinking copolymer resin and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the storage stability of an emulsion by conducting crosslinking polymerization of a specific N-vinylcarboxamide with an oil-soluble vinyl compound containing a polymeric unsaturated group in organic solvents in the presence of an initiator for polymerization and a crosslinking agent, to thereby increase viscosity of the resulting water-in-oil type emulsion and gelate it. SOLUTION: This N-vinylcarboxamide-based crosslinking copolymer resin which has retention amount of 500-3000 in oil, mol.wt. of 10,000-400,000 and an average particle size of 0.1-100 μm is obtained by dissolving (A) 1-30 mol.% N-vinylcarboxamide represented by the formula CH2=CHNR1COR2 (wherein R1 and R2 are and each H or methyl) and (B) 70-99 mol.% of an oil-soluble vinyl compound which has a polymeric unsaturated group in the molecule and whose solubility in 100 g water is not more than 1 g at 20 deg.C, into organic solvents which dissolve components (A) and (B) but not the generated copolymer, and by crosslinking polymerization of the obtained solution at 0-100 deg.C for 1-24 hr in the presence of 0.00001-1 wt.% crosslinking agent per the total amount of the components (A) and (B) in hydrophilic solvents.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an N-vinylcarboxylic acid amide-based crosslinked copolymer resin and a method for producing the same. More specifically, the present invention relates to an N-vinylcarboxylic acid amide-based cross-linked copolymer having a function of absorbing oil even from a water-in-oil (W / O) emulsion, thickening and gelling the entire system, and stably maintaining the oil. The present invention relates to a resin and a method for producing the resin.

[0002]

2. Description of the Related Art Conventional synthetic resin-based oil absorbing agents include, for example, a copolymer of t-butylstyrene / divinylbenzene, a crosslinked polymer of t-butyl methacrylate and / or neopentyl methacrylate, and a crosslinked polymer of methyl methacrylate. Combination, alkyl (meth) having 10 to 16 carbon atoms
Crosslinked polymers of acrylate and the like can be mentioned. Since these oil absorbents absorb oil by absorbing and swelling the oil inside the molecule having a hydrophobic structure, only oil can be selectively used for oil-water mixed oils and thin film oils floating on the water surface. It has advantages such as excellent oil retention after being absorbed once. For example, an oil absorbing agent described in JP-A-5-32708 or JP-A-7-80295 can be used.

[0003]

However, the conventional oil-absorbing agent takes an extremely long time to absorb the oil and absorbs the oil well, but does not have the ability to thicken the water-in-oil emulsion itself. In addition, their fields of use are also limited. For example, in the field of paints and the like, it is required to increase the viscosity of the water-in-oil emulsion itself, and to improve the storage stability of the emulsion and to improve the feeling of use. No oil absorbent is found.

[0004] Until now, various measures have been taken to increase the surface area of the oil absorbing agent by processing the oil absorbing agent into fine particles, but the particles tend to agglomerate as the particles become finer, which is practically expected. The effect is not enough.

An object of the present invention is to improve the disadvantages of the conventional oil absorbing agent, to increase the viscosity of the water-in-oil emulsion itself, to further gel the emulsion, and to improve the storage stability of the emulsion.

It is to provide.

[Means for Solving the Problems]

Thus, the present inventors have conducted various studies, and as a result,
The N-vinyl carboxylic acid amide represented by the general formula CH ₂ ＣＨCHNR ₁ COR ₂ (wherein R ₁ and R ₂ independently represent hydrogen or a methyl group) and the oil-soluble vinyl compound at a specific ratio N- obtained by polymerization and crosslinking with
The present inventors have found that a vinylcarboxylic acid amide-based crosslinked copolymer resin is effective in solving the above-mentioned problems, and have further studied to complete the present invention.

That is, the present invention provides: 1) N-vinyl represented by the general formula (I): CH ₂ ＣＨCHNR ₁ COR ₂ (wherein R ₁ and R ₂ independently represent hydrogen or a methyl group) 1 to 30 mol% of carboxylic acid amide and 70 to 99 mol% of an oil-soluble vinyl compound having one polymerizable unsaturated group in a molecule (hereinafter may be simply referred to as “oil-soluble vinyl compound”). And N-vinylcarboxylic acid amide-based cross-linked copolymer resin characterized by cross-linking and copolymerizing the following. 2) The average particle size of the N-vinyl carboxylic acid amide-based cross-linked copolymer resin particles is 0.1 to 100 μm. The N-vinylcarboxylic acid amide-based crosslinked copolymer resin according to the above item 1), 3) the N-vinylcarboxylic acid amide represented by the general formula (I) is N-vinylacetamide. Do Serial 1) above, wherein the N- vinylcarboxamide-based crosslinked copolymer resin, 4) 1 to 30 mol% of N- vinylcarboxamide of the formula (I) and an oil-soluble vinyl compound from 70 to 99
Mol% of the polymerizable monomer is dissolved in an organic solvent that dissolves the polymerizable monomer but does not dissolve the produced copolymer, and is polymerized and cross-linked in the presence of a polymerization initiator and a cross-linking agent. Method for producing N-vinylcarboxylic acid amide-based crosslinked copolymer resin, 5) Polymerization and crosslinking by further adding a resin particle dispersion stabilizer, wherein N-vinylcarboxylic acid amide-based crosslinking according to the above item 4) 6) The method for producing an N-vinylcarboxylic acid amide-based crosslinked copolymer resin according to 4) above, wherein the organic solvent is an alcohol or an aqueous alcohol. 7) The organic solvent. Is a hydrated aliphatic ketone, The method for producing an N-vinylcarboxylic acid amide-based crosslinked copolymer resin according to the above item 4), wherein

In the N-vinylcarboxylic acid amide-based crosslinked copolymer resin of the present invention, the copolymer resin has the general formula (I)
And an oil-soluble vinyl compound represented by the following formula (1) as at least a monomer. In the following description, “N represented by the general formula (I)”
-Vinylcarboxylic acid amide and oil-soluble vinyl compound "
May be simply referred to as a polymerizable monomer.

The N-vinylcarboxylic acid amide represented by the general formula (I) is indispensable for imparting the effect of improving viscosity and improving stability when a crosslinkable copolymer resin is used as a thickener. Examples thereof include N-vinylformamide, N-vinylacetamide, N-methyl-Nvinylformamide and N-methyl-N-vinylacetamide, among which the copolymer resin obtained has a high affinity for water. Thus, N-vinylacetamide is particularly preferred.

On the other hand, any oil-soluble vinyl compound may be used as long as it has one polymerizable unsaturated group in its molecule.
g or less are preferably used. Examples of such an oil-soluble vinyl compound include ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and 2-ethylhexyl (meth).
Acrylate, n-octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, phenyl (meth) acrylate, octylphenyl (meth) acrylate, nonylphenyl (meth) acrylate, dinonylphenyl (meth) acrylate,
Unsaturated carboxylic esters such as cyclohexyl (meth) acrylate, menthyl (meth) acrylate, isobornyl (meth) acrylate, dibutyl maleate, didodecyl maleate, dodecyl rotonate, didodecyl itaconate; (di) butyl (meth) Acrylamide, (di) dodecyl (meth) acrylamide,
(Di) stearyl (meth) acrylamide, (di) butylphenyl (meth) acrylamide, (di) octylphenyl (meth) acrylamide and other (meth) acrylamide having a hydrocarbon group; 1-hexene, 1-octene, isooctene, Α-olefins such as 1-nonene, 1-decene and 1-dodecene; alicyclic vinyl compounds such as vinylcyclohexane; allyl ethers having a hydrocarbon group such as dodecyl allyl ether; vinyl caproate, vinyl laurate, palmitic acid Vinyl esters having a hydrocarbon group such as vinyl and vinyl stearate;
Vinyl ethers having a hydrocarbon group such as butyl vinyl ether and dodecyl vinyl ether; aromatic vinyl compounds such as styrene, t-butyl styrene, and octyl styrene; and the like. Use of one or more of these vinyl compounds Can be. Among these, at least one aliphatic hydrocarbon group having 3 to 30 carbon atoms is preferable in that it can provide the N-vinylcarboxylic acid amide-based crosslinked copolymer resin as the target substance with more excellent gelling performance. One or two selected from the group consisting of alkyl (meth) acrylate, alkylaryl (meth) acrylate, alkyl (meth) acrylamide, alkylaryl (meth) acrylamide, fatty acid vinyl ester, alkylstyrene and α-olefin having The above vinyl compounds are particularly preferred. In particular, it is preferable to use a vinyl compound having a glass transition point of 20 ° C. or higher, such as t-butyl methacrylate, t-butyl styrene or stearyl methacrylate, as a monomer.

The ratio of the N-vinylcarboxylic acid amide of the general formula (I) to the oil-soluble vinyl compound in the copolymer of the present invention is in the range of 1 to 30 mol%: 70 to 99 mol%, respectively. Within this range, it has an appropriate oil-absorbing property for absorbing oils, sebum, or oils containing water, is excellent in gelling the entire system, and has characteristics preferable as a thickener. More preferably, the N-vinylcarboxylic acid amide is 5 to 20 mol%, and the oil-soluble vinyl compound is
~ 95 mol%.

[0013] The N-vinylcarboxylic acid amide-based crosslinked copolymer resin of the present invention is constituted as described above. However, as long as the oil absorbing property and oil retaining property are not reduced, a vinyl compound having a solubility in 100 g of water exceeding 1 g is used. A small amount may be contained. Examples of such a vinyl compound include methyl methacrylate, (meth) acrylic acid, acrylonitrile, maleic anhydride, fumaric acid, hydroxyethyl (meth) acrylate, polyethylene glycol (meth) acrylate, and methoxypolyethylene glycol (meth) acrylate. Can be mentioned. Next, as the crosslinking agent in the present invention, a crosslinking vinyl compound having at least two polymerizable unsaturated vinyl compounds in a molecule is preferably used. Examples of such a crosslinkable vinyl compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polyethylene glycol-polypropylene glycol di (meth) acrylate, and propylene glycol di (meth) acrylate. Acrylate, polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, N, N'-methylenebis Acrylamide, N, N'-propylenebisacrylamide, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra Preferred are (meth) acrylates, polyfunctional (meth) acrylates and divinylbenzene obtained by esterification of an alkylene oxide adduct of a polyhydric alcohol (for example, glycerin, trimethylolpropane or tetramethylolmethane) with (meth) acrylic acid. For example, one or more of these can be used.

The amount of the cross-linking agent used is determined by the amount of N-
Although the determination of the amount is important because it affects the viscosity of the vinyl carboxylic acid amide crosslinked copolymer particles, the N-
It is often used in the range of 0.0001 to 1% by weight based on the total amount of vinylcarboxylic acid amide and oil-soluble vinyl compound. Specifically, an appropriate amount may be determined in consideration of the amount of N-vinylcarboxylic acid amide used, the type of crosslinking agent, and the degree of thickening performance of the target product.

In the present invention, it is preferable that the crosslinked copolymer resin particles can hold an oil amount of 500 to 3,000 parts by weight based on 100 parts by weight of the resin particles.

The amount of oil retained here indicates how much oil the crosslinked copolymer resin particles absorb and retains per unit weight. Is different. That is, the oil retention here is represented by the sum of the oil absorption of the resin itself in the crosslinked resin particles and the amount of oil retained between the particles,
Such a holding amount is considered to be a characteristic affecting the viscosity increase. Specifically, the retained amount is determined by gently pouring oil into the crosslinked resin particles, allowing the oil to stand for one day, and then centrifuging (1,500 rpm).
m, 10 minutes) to remove the supernatant, measure the weight increase, and calculate the amount of oil retained per 100 parts by weight of the crosslinked copolymer resin particles. In order to exhibit the function as a thickener while maintaining the stability of the emulsion, the oil retention amount is preferably from 500 to 3,000. If this value is less than 500, the oil retention is too small to maintain the stability of the emulsion, and it is not preferable to exceed 3,000.

Next, a method for producing the N-vinylcarboxylic acid amide-based crosslinked copolymer resin of the present invention will be described.

In this production method, N in the general formula (I)
-The vinylcarboxylic acid amide and the oil-soluble vinyl compound are subjected to the polymerization reaction in the above-mentioned ratio. As the reaction solvent at this time, a hydrophilic organic solvent system that dissolves the polymerizable monomer but does not dissolve the copolymerized target product is selected. Here, when a hydrophobic organic solvent is used alone instead of the hydrophilic organic solvent, the entire reaction system undergoes gelation during polymerization,
It becomes difficult to obtain the target substance as a simple powder to be used.

As the above-mentioned hydrophilic solvent, alcohol, hydrated alcohol, or hydrated aliphatic ketone is preferable. Examples of the alcohol include lower alcohols having 6 or less carbon atoms, such as methanol, ethanol, propanol, butanol, and pentanol, and water-containing media. Examples of aliphatic ketones include acetone, methyl ethyl ketone, and methyl propyl having 3 to 6 carbon atoms. Ketones or methyl butyl ketone are particularly preferably used. When water is added to the hydrophilic medium, the amount depends on the type and amount of the organic solvent and monomer used or the degree of uniform solubility, but generally, up to 60% by weight of the whole medium. Used within range.

The polymerization reaction is carried out by dissolving a polymerizable monomer, a cross-linking agent and a polymerization initiator in the hydrophilic organic solvent system and then appropriately heating the resin, whereby the cross-linked copolymerized resin is obtained. Are sequentially deposited. The ratio of the polymerizable monomer to the hydrophilic organic solvent is generally in the range of 1: 3 to 1: in order to remove the heat of reaction, secure a stable polymerization reaction system, and increase the productivity.
A range of 15 is preferred.

As the polymerization initiator, any ordinary radical polymerization initiator can be used as long as it can be uniformly dissolved in the reaction medium in which the polymerizable monomer is dissolved. For example, organic peroxides such as benzoyl peroxide, lauroyl peroxide and cumene hydroperoxide; azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobisdimethylvaleronitrile; Can be used.

In this polymerization reaction system, when a polymer compound which is soluble in the reaction medium and does not participate in the polymerization reaction is added as a resin particle dispersion stabilizer, the crosslinked copolymer resin is in This is extremely advantageous in industrial production because it is deposited with almost no binding state in between and can be prevented from adhering to the wall surface of the reaction vessel. As such a resin particle dispersion stabilizer, a polymer compound having a hydrophilic group and a hydrophobic group is used. Examples of the hydrophilic group include a hydroxyl group, a carboxyl group, and an amide group, and examples of the hydrophobic group include an aliphatic group and an aromatic hydrocarbon group.
The molecular weight is preferably from 10,000 to 400,000, and if it is less than 10,000, sufficient dispersion stability cannot be obtained, and if it is more than 400,000, the viscosity of the reaction system is significantly increased. As a specific example, polyvinyl pyrrolidone, polyvinyl alcohol or polyacrylic acid is preferably used. These resin particle dispersion stabilizers are preferably used in a range of 0.5 to 5 parts by weight based on 100 parts by weight of the reaction medium.

The polymerization temperature varies depending on the type of the polymerizable monomer and the polymerization initiator, but is preferably in the range of 0 to 100 ° C.
Further, it is more preferable to carry out at 60 ° C. or lower. The reaction is appropriately carried out until the polymerization is completed,
4 hours.

After the completion of the polymerization reaction, the precipitated cross-linked copolymer resin is separated by filtration or the like, and if necessary, dried and pulverized to obtain a final product.

The average particle size of the crosslinked copolymer resin is preferably from 0.1 to 100 μm, more preferably 0.2.
５０50 μm. When the particle diameter exceeds 100 μm, it becomes difficult to impart a viscosity increase. The smaller the average particle size, the higher the viscosity and the stability of the emulsion, but it is practically difficult to obtain a powder smaller than the above. The value of the average particle size in the present specification is a value measured by a Coulter counter.

The N-vinylcarboxylic acid amide-based crosslinked copolymer resin of the present invention has a function of well absorbing oil even from a water-in-oil emulsion, and has a function of thickening and gelling the entire system to stably maintain the oil. Since this resin has a hydrophobic portion and a hydrophilic portion, it also plays a role of a kind of surfactant. That is, while the hydrophilic portion is adsorbed on the surface of the water droplet in the emulsion, the hydrophobic portion absorbs and gelates the oil around the water droplet. Therefore, an oil-absorbing gel exists around the water droplets,
It is considered that the emulsion functions as a thickener while maintaining the stability of the emulsion.

The conventional oil-absorbing agent does not have a hydrophilic portion, and thus does not have a surfactant effect. Although the effect of temporarily thickening the emulsion is observed, the emulsion separates with the passage of time. No effect of thickening is observed. The N-vinylcarboxylic acid amide-based crosslinked copolymer resin of the present invention can exhibit such excellent effects.

The crosslinked copolymer resin of the present invention can be used as a base material or a quality improving agent for gel products in the field of, for example, paints. At the time of use, the emulsion itself is thickened simply by adding and mixing under stirring so that the powder of the crosslinked copolymer resin has a concentration of usually 5 to 15% by weight with respect to the emulsion to be thickened and gelled. Can gel.

[0029]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, Comparative Examples and Test Examples, but the present invention is not limited thereto.

Example 1 In a 500 ml four-neck separable flask connected to a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, t-butyl methacrylate (monomer) was used as a monomer.
29.1 g (corresponding to 95 mol%) of 0.9 g (corresponding to 5 mol%) of 1,6-hexanediol as a crosslinking agent 0.15 dimethacrylate
g, 2,2 azobis 2,4 dimethylvaleronitrile 0.1 g.
After 3 g and 210 g of methanol were taken and uniformly dissolved, the atmosphere was sufficiently replaced with nitrogen gas. Next, the temperature was raised to 40 ° C. to start the polymerization reaction. The mixture was left as it was for 24 hours while stirring, and after completion of the polymerization, cooling, filtration,
Drying and pulverization were performed to obtain a white powder having an average particle diameter of 5 microns.

Example 2 In Example 1, t-butyl methacrylate was added at 26.
Except that 1 g (corresponding to 80 mol%) and N-vinylacetamide were changed to 3.9 g (corresponding to 20 mol%), the same treatment as in Example 1 was carried out to obtain a white powder having an average particle diameter of 2 μm. I got

Example 3 In Example 1, t-butyl methacrylate was replaced with stearyl methacrylate (solubility in water at 0 ° C: 0.0
0 g / 100 g, equivalent to 89 mol%), and replacing methanol with ethanol, and using polyvinylpyrrolidone (GAF Co., K-60) as a resin particle dispersion stabilizer.
Except for using 3 g, the same treatment as in Example 1 was performed to obtain a white powder having an average particle diameter of 8 μm. At this time, no resin adhered to the wall surface of the flask.

Example 4 In a 500 ml four-neck separable flask connected to a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, 14.3 g (26 g) of stearyl methacrylate was added.
Mol%), t-butyl methacrylate 14.
3 g (corresponding to 63 mol%), 1.4 g (corresponding to 11 mol%) of N-vinylacetamide, 0.15 g of 1,6 hexanediol diacrylate, 0.3 g of 2,2 azobis 2,4 dimethylvaleronitrile , Ethanol 2
After 50 g and 50 g of water were taken and uniformly dissolved, the atmosphere was sufficiently replaced with nitrogen gas. The temperature was raised to 40 ° C. to initiate polymerization. After holding for about 24 hours, cooling, filtration, drying, and pulverization were performed to obtain a white powder having an average particle diameter of 5 microns.

Example 5 In Example 4, t-butyl methacrylate was added to 14.9 g of t-butyl styrene (0.000 g / 100 g of solubility in water at 20 ° C., corresponding to 60 mol%) with N
A white powder having an average particle diameter of 1 micron was obtained by treating in the same manner as in Example 4, except that 1.5 g (corresponding to 11 mol%) of -vinylacetamide was respectively used.

Example 6 In Example 4, acetone 150 was used instead of ethanol.
g of water and 150 g of water, except that a mixed solvent containing 150 g of water was used to obtain a white powder having an average particle diameter of 1 micron.

Example 7 In Example 4, polyvinyl alcohol [Nippon Synthetic Chemical Industry Co., Ltd.] was used as a stabilizer for dispersing resin particles in ethanol.
[GL-05] was dissolved in the same manner as in Example 4 except that 9 g of a white powder having an average particle diameter of 2 μm was obtained. At this time, no resin adhered to the wall surface of the flask.

Comparative Example 1 The procedure of Example 1 was repeated, except that only 30 g (100 mol%) of t-butyl methacrylate was used as a monomer. A powder was obtained.

Comparative Example 2 In Example 1, the amount of t-butyl methacrylate was changed to 2
The same procedure as in Example 1 was repeated, except that the amount of N-vinylacetamide was changed to 1.5 g (corresponding to 60 mol%) and the amount of N-vinylacetamide was changed to 8.5 g (corresponding to 40 mol%). A white powder with a diameter of 5 microns was obtained.

Comparative Example 3 The procedure of Example 1 was repeated, except that ethanol was replaced with acetone. However, the entire processing system was solidified and a fine powder could not be obtained.

Comparative Example 4 In Example 4, stearyl methacrylate and t
-28.6 g of methyl methacrylate instead of butyl methacrylate (solubility in water at 20 ° C. 1.72 g /
100 g of water, corresponding to 96 mol%)
The same treatment as in Example 4 was performed to obtain a white powder having an average particle diameter of 5 μm.

Test Example 1 (Measurement of Oil Retention Amount) 1.0 g of the cross-linked copolymer resin was weighed into a centrifuge tube, and toluene and cetyl octanoate were gently poured and left overnight. Centrifugation (1,500 rpm, 10
After that, the supernatant was removed, the weight (a) was measured, and the oil retention was calculated by the following equation.

Oil retention (parts by weight) = (a-1) g × 100 The results of measuring the oil retention of the crosslinked copolymer resins obtained in Example 1, Comparative Examples 2 and 4 by the above method. Are shown in Table 1.

[0043]

[Table 1] As shown in the results of Table 1, the N-carboxylic acid amide-based cross-linked copolymer resin of the present invention obtained in Example 1 had a sufficient oil retention when poured with toluene or ethyl octanoate and allowed to stand. Indicated. On the other hand, even when the polymer obtained in Comparative Example was used, the oil retention amount was not sufficient.

Test Example 2 (Test for Evaluating Thickening of W / O Emulsion) The following formulation was emulsified using a homogenizer to prepare a W / O emulsion.

Emulsion 1 Cetyl octanoate 80 g Deionized water 20 g Sorbitan monooleate 1.0 g Emulsion 2 Toluene 80 g Deionized water 20 g Sorbitan monooleate 1.0 g Obtained in the above Examples and Comparative Examples in 100 g of each emulsion. 10 g of the obtained powder was added and dispersed sufficiently, and allowed to stand still at room temperature. The emulsion state immediately after dispersion and 30 days later was visually observed and evaluated according to the following criteria. The viscosity of the emulsion at that time was measured at room temperature using a B8H type viscometer (rotational speed: 20 rpm). Table 2 shows the results.

…: No change or slight emulsion separation is observed.

X: Either the emulsion was considerably separated or completely separated into two layers.

The same evaluation was performed for the emulsion when the amount of the powder obtained in each of the above Examples and Comparative Examples was 5 g in 100 g of the above emulsion. Table 3 shows the results.

[0049]

[Table 2] As shown in the results in Table 2, when the N-vinylcarboxylic acid amide-based cross-linked copolymer resin of the present invention was added to the W / O emulsion and treated, the emulsion itself became thick and no fluidity was observed (gelation). ), That state could be maintained for a long time. On the other hand, with the polymer obtained in Comparative Example, the emulsion could not be gelled, or even if gelled, the gel was not stable for a long period of time and separated into two layers, and the viscosity was lowered.

[0050]

[Table 3] As shown in the results in Table 3, when the N-vinylcarboxylic acid amide-based crosslinked copolymer resin of the present invention was added to the W / O emulsion and treated, the emulsion itself was thickened and the emulsion was stably maintained for a long period of time. Could be maintained. On the other hand, when the polymer obtained in the comparative example was used, the emulsion appeared to be stable at an early stage, but it was found that the emulsion separated over time and was inferior in the thickening effect.

[0051]

The N-vinylcarboxylic acid amide-based cross-linked copolymer resin of the present invention is excellent in the function of thickening and further gelling the water-in-oil emulsion itself. It can be suitably used as a quality improving agent for enhancing the storage stability and improving the usability.

[0052]

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) (C08F 246/00 226: 02) (C08F 220/18 226: 02) F term (Reference) 4J011 HA03 HA08 4J038 CB111 CB121 CC021 CC071 CE022 CE051 CF011 CG032 CG141 CG151 CG171 CJ141 CK032 FA072 FA092 FA102 FA122 FA272 JA19 JA33 JA66 JB16 KA03 KA06 KA09 NA26 4J100 AA15Q AA16Q AA19Q AA20Q AA21Q AB02R AB03R AE02R AE05Q AG02R AG05Q AL03Q AL04Q AL05Q AL08Q AL14Q AL34Q AL44Q AM19Q AM21Q AN04P BA12P BA13P BC02Q BC04Q BC07Q BC43Q CA04 CA31 DA36 FA02 FA03 FA30 HA53 HC36 HC42 JA01 JA05

Claims (7)

[Claims] 1. An N-vinylcarboxylic acid amide represented by the general formula CH ₂ ＣＨCHNR ₁ COR ₂ (wherein R ₁ and R ₂ independently represent hydrogen or a methyl group) in an amount of 1 to 30 mol%. An N-vinyl carboxylic acid amide-based cross-linked copolymer resin obtained by cross-linking and copolymerizing 70 to 99 mol% of an oil-soluble vinyl compound having one polymerizable unsaturated group in the molecule. 2. The crosslinked N-vinylcarboxylic acid amide resin according to claim 1, wherein the average particle size of the N-vinylcarboxylic acid amide crosslinked copolymer resin particles is 0.1 to 100 μm. . 3. The crosslinked N-vinylcarboxylic acid amide resin according to claim 1, wherein the N-vinylcarboxylic acid amide is N-vinylacetamide. 4. An N-vinylcarboxylic acid amide represented by the general formula CH ₂ ＣＨCHNR ₁ COR ₂ (wherein R ₁ and R ₂ independently represent hydrogen or a methyl group) in an amount of 1 to 30 mol%. And 70 to 99 mol% of an oil-soluble vinyl compound having one polymerizable unsaturated group in the molecule is dissolved in an organic solvent which dissolves these polymerizable monomers but does not dissolve the produced copolymer. A method for producing an N-vinylcarboxylic acid amide-based crosslinked copolymer resin, which comprises polymerizing and crosslinking in the presence of a polymerization initiator and a crosslinking agent. 5. The method for producing an N-vinyl carboxylic acid amide-based crosslinked copolymer resin according to claim 4, wherein the polymerization and crosslinking are carried out by further adding a resin particle dispersion stabilizer. 6. The method for producing an N-vinylcarboxylic acid amide-based crosslinked copolymer resin according to claim 4, wherein the organic solvent is an alcohol or an aqueous alcohol. 7. The method according to claim 4, wherein said organic solvent is a hydrated aliphatic ketone.