JP3805531B2 - Oil-absorbing agent comprising N-vinylcarboxylic acid amide-based crosslinked copolymer resin and method for producing the same - Google Patents

Description

表１の結果に示されるように、実施例１で得られた本発明のＮ−カルボン酸アミド系架橋共重合樹脂は、トルエンまたはオクタン酸エチルを注いで放置するとき、十分な油保持量を示した。一方、比較例で得られた重合体を用いても油保持量が十分でなかった。
【００４４】
試験例２
（Ｗ／Ｏエマルジョンの増粘性評価試験）
下記の配合物を、ホモジナイザーを用いて乳化し、Ｗ／Ｏエマルジョンを調製した。
【００４５】
エマルジョン１
オクタン酸セチル ８０ｇ
脱イオン水 ２０ｇ
ソルビタンモノオレエート １.０ｇ
エマルジョン２
トルエン ８０ｇ
脱イオン水 ２０ｇ
ソルビタンモノオレエート １.０ｇ
各エマルジョン１００ｇ中に、上記の実施例および比較例で得られた粉末１０ｇを加え十分に分散させ、室温下に静置し、分散直後および３０日後のエマルジョン状態を肉眼観察して、下記の基準で評価した。また、その時のエマルジョンの粘度を室温でＢ８Ｈ型粘度計（回転数：２０ｒｐｍ）を用いて測定した。その結果を表２に示す。
【００４６】
○…変化なしかあるいはエマルジョン分離がわずかに見られる。
【００４７】
×…エマルジョンの分離がかなり見られるかあるいは完全に二層に
分離している。
【００４８】
また、上記エマルジョン１００ｇ中に上記実施例および比較例で得られた粉末の添加量が５ｇの時のエマルジョンについても同様に評価した。その結果を表３に示す。
【００４９】
【表２】

表２の結果に示されるように、本発明のＮ−ビニルカルボン酸アミド系架橋共重合樹脂をＷ／Ｏエマルジョンに加えて処理すると、エマルジョンそのものが増粘し流動性が見られなくなり（ゲル化）、その状態では長期間にわたり保持することができた。一方、比較例で得た重合体ではエマルジョンをゲル化できないか、あるいはゲル化できたとしてもそのゲルは長期間安定せず二層に分離し、粘度も低下した。
【００５０】
【表３】

表３の結果に示されるように、本発明のＮ−ビニルカルボン酸アミド系架橋共重合樹脂をＷ／Ｏエマルジョンに加えて処理すると前記エマルジョンそのものを増粘させると共に、長期間にわたってエマルジョンを安定に維持することができた。一方、比較例で得た重合体を用いるとエマルジョンは初期には安定に見えたが、経時によって、分離し、また増粘効果にも劣ることが判った。
【００５１】
【発明の効果】
本発明のＮ−ビニルカルボン酸アミド系架橋共重合樹脂は、油中水型エマルジョンそのものを増粘、さらにはゲル化する機能に優れているため、塗料等の分野における製品の保存安定性を高めたり、使用感をよくなどの品質改良剤として好適に使用することができる。
【００５２】[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an N-vinylcarboxylic acid amide-based crosslinked copolymer resin and a method for producing the same. In more detail, the present invention absorbs oil even from a water-in-oil (W / O) emulsion, thickens the entire system, and has a function of stably maintaining the N-vinylcarboxylic acid amide-based cross-linking copolymer. The present invention relates to a resin and a method for producing the same.
[0002]
[Prior art]
Examples of conventional synthetic resin-based oil absorbents include copolymers of t-butylstyrene / divinylbenzene, cross-linked polymers of t-butyl methacrylate and / or neopentyl methacrylate, cross-linked polymers of methyl methacrylate, and 10 carbon atoms. -16 alkyl (meth) acrylate cross-linked polymers and the like. These oil-absorbing agents absorb oil by absorbing and swelling oil inside the molecules that have a hydrophobic structure. Therefore, only the oil content is selective to the oil content of the oil-water mixture system and the thin film oil floating on the water surface. In addition, it has advantages such as excellent oil retaining ability after absorption. For example, the oil absorbing agent described in JP-A-5-32708 or JP-A-7-80295 can be mentioned.
[0003]
[Problems to be solved by the invention]
However, conventional oil absorbents have a very long time to absorb the oil and absorb oil well but have no ability to thicken the water-in-oil emulsion itself. Yes. For example, in the field of paints and the like, it is required to thicken the water-in-oil emulsion itself, to improve the storage stability of the emulsion, and to improve the feeling of use, which is suitable for such purposes. There is no oil absorber.
[0004]
So far, the oil absorbing agent has been processed into fine particles to increase the surface area of the oil absorbing agent. A sufficient effect has not been obtained.
[0005]
The object of the present invention is to improve the shortcomings of conventional oil absorbents, increase the viscosity of the water-in-oil emulsion itself, further gelate it, and improve the storage stability of the emulsion.
It is to provide .
[Means for Solving the Problems]
[0007]
Therefore, as a result of various studies, the present inventors have found that N-vinylcarboxylic acid represented by the general formula CH ₂ = CHNR ₁ COR ₂ (wherein R ₁ and R ₂ independently represent hydrogen or a methyl group). An N-vinylcarboxylic acid amide-based crosslinked copolymer resin obtained by polymerizing and crosslinking an acid amide and an oil-soluble vinyl compound having a solubility in 100 g of water of 1 g or less at 20 ° C. is effective in solving the above problems. As a result, the inventors have further studied and completed the present invention.
[0008]
That is, the present invention
1) General formula (I)
CH ₂ = CHNR ₁ COR ₂
(Wherein R ₁ and R ₂ independently represent hydrogen or a methyl group) 1 to 30 mol% of N-vinylcarboxylic acid amide represented by 1 and one polymerizable unsaturated group in the molecule. and, and oil-soluble vinyl compound solubility in water 100g is 1g or less at 20 ° C. obtained by crosslinking copolymerization of a 70 to 99 mol% (hereinafter, simply is abbreviated as "oil-soluble vinyl compound") An oil absorbent comprising an N-vinylcarboxylic acid amide-based cross-linked copolymer resin,
2) The oil-absorbing agent according to 1) above, wherein the N-vinylcarboxylic acid amide-based crosslinked copolymer resin particles have an average particle size of 0.1 to 100 μm,
3) The oil absorbing agent according to 1) above, wherein the N-vinylcarboxylic amide represented by the general formula (I) is N-vinylacetamide,
4) 1-30 mol% of the N-vinylcarboxylic acid amide represented by the general formula (I) and 70-99 mol% of the oil-soluble vinyl compound are dissolved in these polymerizable monomers. The polymer is dissolved in an organic solvent that does not dissolve, and in the presence of a polymerization initiator and a crosslinking agent, the polymer is crosslinked to obtain an N-vinylcarboxylic acid amide-based crosslinked copolymer resin, and the copolymer resin is used as an oil absorbing agent. A method for producing an oil-absorbing agent ,
5) The method for producing an oil absorbent as described in 4) above, wherein an N-vinylcarboxylic acid amide-based crosslinked copolymer resin obtained by further adding a resin particle dispersion stabilizer and polymerizing and crosslinking is used as the oil absorbent. ,
Above 4) manufacturing method of claim wherein the oil agent 6) said organic solvent is characterized in that an alcohol or a hydrous alcohol.
7) the 4) method of manufacturing claim wherein the oil agent, wherein the organic solvent is water-containing aliphatic ketones.
[0009]
In the N-vinylcarboxylic acid amide-based cross-linked copolymer resin of the present invention, the copolymer resin is composed of at least monomers of N-vinylcarboxylic acid amide represented by the general formula (I) and an oil-soluble vinyl compound. The In the following description, the “N-vinylcarboxylic acid amide represented by the general formula (I) and the oil-soluble vinyl compound” may be collectively referred to as a polymerizable monomer.
[0010]
The N-vinylcarboxylic acid amide represented by the general formula (I) is essential for imparting a thickening improvement effect and a stability improvement effect when a crosslinkable copolymer resin is used as a thickening agent. , N-vinylformamide, N-vinylacetamide, N-methyl-N vinylformamide, N-methyl-N-vinylacetamide, etc., among which N is particularly preferred because the resulting copolymer resin has a high affinity for water. -Vinylacetamide is preferred.
[0011]
On the other hand, any oil-soluble vinyl compound may be used as long as it has one polymerizable unsaturated group in its molecule, and those having a solubility in 100 g of water of 1 g or less at 20 ° C. are preferably used. Examples of such oil-soluble vinyl compounds include ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 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, cyclohexyl (meth) ) Unsaturated carboxylic acids such as acrylate, menthyl (meth) acrylate, isobornyl (meth) acrylate, dibutyl maleate, didodecyl maleate, dodecyl crotonate, didodecyl itaconate Esters; (di) butyl (meth) acrylamide, (di) dodecyl (meth) acrylamide, (di) stearyl (meth) acrylamide, (di) butylphenyl (meth) acrylamide, (di) octylphenyl (meth) acrylamide, etc. (Meth) acrylamide having a hydrocarbon group; α-olefin such as 1-hexene, 1-octene, isooctene, 1-nonene, 1-decene, 1-dodecene; alicyclic vinyl compound such as vinylcyclohexane; dodecyl allyl ether An allyl ether having a hydrocarbon group such as vinyl ester having a hydrocarbon group such as vinyl caproate, vinyl laurate, vinyl palmitate and vinyl stearate; a vinyl ether having a hydrocarbon group such as butyl vinyl ether and dodecyl vinyl ether; Styrene, t- butyl styrene, and aromatic vinyl compounds such as octyl styrene can be mentioned, may be used alone or two or more of these vinyl compounds. Among these, at least one aliphatic hydrocarbon group having 3 to 30 carbon atoms in that it can give better gelling performance to the target N-vinylcarboxylic acid amide-based crosslinked copolymer resin. 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 The above vinyl compounds are particularly preferred. Among them, it is preferable to use as a monomer a vinyl compound having a glass transition point of 20 ° C. or higher, such as t-butyl methacrylate, t-butyl styrene, or stearyl methacrylate.
[0012]
In the copolymer of the present invention, the ratio of the N-vinylcarboxylic acid amide of the general formula (I) to the oil-soluble vinyl compound having a solubility in 100 g of water of 1 g or less at 20 ° C. is 1 to 30 mol%: 70 to It is in the range of 99 mol%. If it is this range, it has the moderate oil-absorbing performance which absorbs the oil agent containing oil agent, sebum, or water, is excellent in the performance which makes the whole system gelatinize, and has a characteristic preferable as a thickener. More preferably, N-vinylcarboxylic acid amide is 5 to 20 mol%, and the oil-soluble vinyl compound is 80 to 95 mol%.
[0013]
The N-vinylcarboxylic acid amide-based cross-linked copolymer resin of the present invention is constituted as described above, but contains a small amount of a vinyl compound having a solubility in 100 g of water exceeding 1 g as long as its oil absorption and oil retention are not lowered. It may be. Examples of such vinyl compounds 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 crosslinkable vinyl compound having at least two polymerizable unsaturated vinyl compounds in the molecule is preferably used. Examples of such crosslinkable vinyl compounds 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, 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, tetramethylol methane tetra Preference is given to polyfunctional (meth) acrylates and divinylbenzene obtained by esterification of (meth) acrylic acid with alkylene oxide adducts of (meth) acrylates and polyhydric alcohols (eg glycerin, trimethylolpropane or tetramethylolmethane) Illustrated, one or more of these may be used.
[0014]
The amount of the crosslinking agent used affects the thickening of the N-vinylcarboxylic acid amide crosslinked copolymer particles that are the target product, and therefore determination of the amount is important. Usually, however, N-vinylcarboxylic acid amide and oil It is often used in the range of 0.0001 to 1% by weight based on the total amount with the soluble vinyl compound. Specifically, an appropriate amount of use may be determined in consideration of the amount of N-vinylcarboxylic acid amide used, the type of crosslinking agent, the degree of thickening performance of the target product, and the like.
[0015]
In the present invention, it is preferable that the cross-linked copolymer resin particles can hold an oil amount of 500 to 3,000 parts by weight with respect to 100 parts by weight of the resin particles.
[0016]
The oil retention amount here indicates how much oil the crosslinked copolymer resin particles absorb and retain per unit weight, and is different from the oil absorption capacity of the oil-absorbing resin itself. That is, the oil retention amount here is expressed as the sum of the oil absorption amount of the resin itself in the crosslinked resin particles and the oil amount retained between the particles, and the retention amount affects the viscosity increase. It is considered a characteristic. Specifically, the retained amount was measured by measuring the increase in weight when the oil was gently poured into the cross-linked resin particles and allowed to stand for 1 day, then centrifuged (1,500 rpm, 10 minutes) to remove the supernatant. The amount of oil retained per 100 parts by weight of the cross-linked copolymer resin particles is calculated. In order to exhibit the function as a thickener while maintaining the stability of the emulsion, the oil retention amount is preferably 500 to 3,000. When this value is less than 500, the amount of oil retained is too small to make it difficult to maintain the stability of the emulsion, and it is not preferable to exceed 3,000.
[0017]
Next, the manufacturing method of the N-vinylcarboxylic acid amide type | system | group crosslinked copolymer resin of this invention is demonstrated.
[0018]
In this production method, the N-vinylcarboxylic acid amide of the general formula (I) and the oil-soluble vinyl compound having a solubility in 100 g of water of 1 g or less at 20 ° C. are subjected to the polymerization reaction at the aforementioned 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 at the time of polymerization, making it difficult to obtain the target product as a simple powder to use.
[0019]
As the hydrophilic solvent, alcohol, hydrous alcohol, or hydrous aliphatic ketone is preferable. Examples of the alcohol include lower alcohols such as methanol, ethanol, propanol, butanol and pentanol having 6 or less carbon atoms or water-containing media thereof, and aliphatic ketones include acetone, methyl ethyl ketone and methylpropyl 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 entire medium. Used within range.
[0020]
The polymerization reaction is carried out by dissolving a polymerizable monomer, a crosslinking agent, and a polymerization initiator in the hydrophilic organic solvent system, and then appropriately heating, whereby a crosslinked copolymerized resin is sequentially deposited. It will be. In general, the ratio of the polymerizable monomer to the hydrophilic organic solvent is preferably in the range of 1: 3 to 1:15 in order to secure removal of heat of reaction and a stable polymerization reaction system to increase productivity.
[0021]
As the polymerization initiator, an ordinary radical polymerization initiator can be used as long as it is 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.
[0022]
In this polymerization reaction system, when a polymer compound that is soluble in the reaction medium and does not participate in the polymerization reaction is added as a resin particle dispersion stabilizer, the cross-linked copolymer resin is in the form of a powder and is bonded between the particles. This is very advantageous in industrial production because it is deposited in a state where there is almost no adhesion, and can be prevented from adhering to the wall 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 10,000 to 400,000, and if it is 10,000 or less, sufficient dispersion stability cannot be obtained, and if it exceeds 400,000, the viscosity of the reaction system increases remarkably, which is not preferable. As specific examples, polyvinylpyrrolidone, polyvinyl alcohol, or polyacrylic acid is preferably used. These resin particle dispersion stabilizers are preferably used in the range of 0.5 to 5 parts by weight with respect to 100 parts by weight of the reaction medium.
[0023]
Although polymerization temperature changes with kinds of a polymerizable monomer and a polymerization initiator, the range of 0-100 degreeC is preferable, and also it is more preferable to implement at 60 degrees C or less. The reaction is appropriately carried out until the polymerization is completed, but it is 1 to 24 hours.
[0024]
After the completion of the polymerization reaction, the precipitated cross-linked copolymer resin is separated by filtration or the like, and dried, pulverized, or the like as necessary to obtain a final product.
[0025]
The average particle size of the crosslinked copolymer resin is preferably 0.1 to 100 μm, and more preferably 0.2 to 50 μm. When the particle diameter exceeds 100 μm, it is difficult to impart thickening. As the average particle size decreases, the thickening and emulsion stability improve, but in practice it is difficult to obtain a powder smaller than the above. The value of the average particle diameter in the present specification is a value measured by a Coulter counter.
[0026]
The N-vinylcarboxylic acid amide-based cross-linked copolymer resin of the present invention has a function of absorbing oil well even from a water-in-oil emulsion and thickening and gelling the entire system to keep it stable. Since this resin has a hydrophobic part and a hydrophilic part, it also plays a kind of surface active role. That is, while the hydrophilic portion is adsorbed on the surface of the water droplet in the emulsion, the hydrophobic portion absorbs oil around the water droplet. Therefore, since the oil-absorbing gel exists in a form surrounding the water droplets, it is considered that the function as a thickener is exhibited while maintaining the stability of the emulsion.
[0027]
The conventional oil absorbent does not have a hydrophilic part, so there is no surfactant effect, and although the effect of temporarily thickening the emulsion is seen, the emulsion separates with time and eventually increases. There is no sticky effect. The N-vinylcarboxylic acid amide-based crosslinked copolymer resin of the present invention can exhibit such excellent effects.
[0028]
The crosslinked copolymer resin of the present invention can be used as a base material or a quality improver for gel-like products in the field of paints, for example. In use, the emulsion itself is thickened simply by adding and mixing the agglomerated copolymer resin powder under stirring to the emulsion to be thickened and gelled so that the concentration is usually 5 to 15% by weight. It can be gelled.
[0029]
【Example】
EXAMPLES Next, although an Example, a comparative example, and a test example are given and this invention is demonstrated further in detail, this invention is not limited to this.
[0030]
Example 1
In a four-necked separable flask having a capacity of 500 milliliters connected with a stirrer, thermometer, reflux condenser and nitrogen gas introduction tube, t-butyl methacrylate as a monomer (solubility in water at 20 ° C .: 0.05 g) / 100 g) of 29.1 g (corresponding to 95 mol%), 0.9 g of N-vinylacetamide (corresponding to 5 mol%), 0.15 g of 1,6-hexanediol dimethacrylate as a crosslinking agent, 2,2 After taking 0.3 g of azobis 2,4 dimethylvaleronitrile and 210 g of methanol and dissolving them uniformly, the gas was sufficiently replaced with nitrogen gas. Next, the temperature was raised to 40 ° C. to initiate the polymerization reaction. The mixture was allowed to stand for 24 hours with stirring, and after the polymerization was completed, cooling, filtration, drying and pulverization were performed to obtain a white powder having an average particle size of 5 microns.
[0031]
Example 2
In Example 1, the same procedure as in Example 1 was performed except that 26.1 g (corresponding to 80 mol%) of t-butyl methacrylate and 3.9 g (corresponding to 20 mol%) of N-vinylacetamide were replaced. Processing gave a white powder with an average particle size of 2 microns.
[0032]
Example 3
In Example 1, t-butyl methacrylate was replaced with stearyl methacrylate (solubility in water at 20 ° C .: 0.00 g / 100 g, corresponding to 89 mol%), and methanol was replaced with ethanol as a resin particle dispersion stabilizer. A white powder having an average particle size of 8 microns was obtained in the same manner as in Example 1 except that 3 g of polyvinylpyrrolidone (manufactured by G.A.F.Co, K-60) was used. At this time, no resin was observed on the wall of the flask.
[0033]
Example 4
In a 500 ml four-necked separable flask connected with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 14.3 g of stearyl methacrylate (corresponding to 26 mol%), t-butyl methacrylate 14. 3 g (corresponding to 63 mol%), 1.4 g of N-vinylacetamide (corresponding to 11 mol%), 0.15 g of 1,6 hexanediol diacrylate, 0.3 g of 2,2 azobis 2,4 dimethylvaleronitrile Then, 250 g of ethanol and 50 g of water were taken and dissolved uniformly, and then sufficiently substituted 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 size of 5 microns.
[0034]
Example 5
In Example 4, 14.9 g of t-butylmethacrylate (0.00 g / 100 g of water solubility at 20 ° C., corresponding to 60 mol%) was added to 1.5 g of N-vinylacetamide (11%). A white powder having an average particle diameter of 1 micron was obtained in the same manner as in Example 4 except that each was replaced with (corresponding to mol%).
[0035]
Example 6
In Example 4, a white powder having an average particle diameter of 1 micron was obtained in the same manner as in Example 4 except that a mixed solvent containing 150 g of acetone and 150 g of water was used instead of ethanol.
[0036]
Example 7
In Example 4, the treatment was performed in the same manner as in Example 4 except that 9 g of polyvinyl alcohol (GL-05, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was dissolved in ethanol as a resin particle dispersion stabilizer. A white powder with a diameter of 2 microns was obtained. At this time, no resin was observed on the wall of the flask.
[0037]
Comparative Example 1
In Example 1, a treatment was performed in the same manner as in Example 1 except that only 30 g (100 mol%) of t-butyl methacrylate was used as a monomer to obtain a white powder having an average particle diameter of 5 microns.
[0038]
Comparative Example 2
In Example 1, the amount of t-butyl methacrylate was changed to 21.5 g (corresponding to 60 mol%) and the amount of N-vinylacetamide was changed to 8.5 g (corresponding to 40 mol%). The same treatment as in No. 1 was performed to obtain a white powder having an average particle diameter of 5 microns.
[0039]
Comparative Example 3
In Example 1, treatment was performed in the same manner as in Example 1 except that ethanol was replaced with acetone. However, the entire treatment system was solidified and fine powder could not be obtained.
[0040]
Comparative Example 4
In Example 4, instead of stearyl methacrylate and t-butyl methacrylate, 28.6 g of methyl methacrylate (1.72 g of water solubility at 20 ° C./100 g of water, corresponding to 96 mol%) was used. The same treatment as in No. 4 was performed to obtain a white powder having an average particle diameter of 5 microns.
[0041]
Test example 1
(Measurement of oil retention)
1.0 g of a cross-linked copolymer resin was weighed into a centrifuge tube, and toluene and cetyl octanoate were poured gently and left for a whole day and night. After centrifugation (1,500 rpm, 10 minutes), the supernatant was removed, the weight (a) was measured, and the oil retention was calculated according to the following formula.
[0042]
Oil retention (parts by weight) = (a-1) g × 100
Table 1 shows the results of measuring the oil retention amount of the crosslinked copolymer resins obtained in Example 1, Comparative Example 2 and Comparative Example 4 by the above method.
[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 has a sufficient oil holding amount when poured with toluene or ethyl octoate and allowed to stand. Indicated. On the other hand, even when the polymer obtained in the comparative example was used, the oil retention amount was not sufficient.
[0044]
Test example 2
(Thickening evaluation test of W / O emulsion)
The following formulation was emulsified using a homogenizer to prepare a W / O emulsion.
[0045]
Emulsion 1
80g cetyl octoate
20g of deionized water
Sorbitan monooleate 1.0g
Emulsion 2
Toluene 80g
20g of deionized water
Sorbitan monooleate 1.0g
In 100 g of each emulsion, 10 g of the powder obtained in the above Examples and Comparative Examples was added and sufficiently dispersed, allowed to stand at room temperature, and the emulsion state immediately after dispersion and 30 days later was observed with naked eyes. It was evaluated with. Further, the viscosity of the emulsion at that time was measured at room temperature using a B8H viscometer (rotation speed: 20 rpm). The results are shown in Table 2.
[0046]
○: No change or slight emulsion separation.
[0047]
X: There is considerable separation of the emulsion or it is completely separated into two layers.
[0048]
Further, the evaluation was similarly made for the emulsion when the amount of the powder obtained in the above Examples and Comparative Examples was 5 g in 100 g of the emulsion. The results are shown in Table 3.
[0049]
[Table 2]

As shown in the results of Table 2, when the N-vinylcarboxylic acid amide-based cross-linked copolymer resin of the present invention is added to a W / O emulsion for treatment, the emulsion itself thickens and no fluidity is observed (gelation). ), And could be held for a long time in that state. On the other hand, with the polymer obtained in the comparative example, the emulsion could not be gelled, or even if gelled, the gel was not stable for a long time and separated into two layers, and the viscosity also decreased.
[0050]
[Table 3]

As shown in the results of Table 3, when the N-vinylcarboxylic acid amide-based crosslinked copolymer resin of the present invention is added to a W / O emulsion, the emulsion itself is thickened and the emulsion is stabilized over a long period of time. Could be maintained. On the other hand, when the polymer obtained in the comparative example was used, the emulsion looked stable at the beginning, but it was found that it separated with time and was inferior in the thickening effect.
[0051]
【The invention's effect】
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, thereby improving the storage stability of products in the field of paints and the like. Or can be suitably used as a quality improver with a good feeling of use.
[0052]

Claims (7)

₁ to 30 mol% of N-vinylcarboxylic acid amide represented by the general formula CH ₂ ═CHNR ₁ COR ₂ (wherein R ₁ and R ₂ independently represent hydrogen or a methyl group) and 1 in the molecule N-vinylcarboxylic acid amide type cross-linkage obtained by cross-linking copolymerization of 70 to 99 mol% of an oil-soluble vinyl compound having one polymerizable unsaturated group and having a solubility in 100 g of water of 1 g or less at 20 ° C. An oil absorbent made of a copolymer resin. The oil-absorbing agent according to claim 1, wherein the N-vinylcarboxylic acid amide-based crosslinked copolymer resin particles have an average particle size of 0.1 to 100 µm. The oil absorbing agent according to claim 1, wherein the N-vinylcarboxylic acid amide is N-vinylacetamide. ₁ to 30 mol% of N-vinylcarboxylic acid amide represented by the general formula CH ₂ ═CHNR ₁ COR ₂ (wherein R ₁ and R ₂ independently represent hydrogen or a methyl group) and 1 in the molecule 70-99 mol% of an oil-soluble vinyl compound having 1 polymerizable unsaturated group and having a solubility in 100 g of water of 1 g or less at 20 ° C. was produced to dissolve these polymerizable monomers. dissolved in an organic solvent which does not dissolve the copolymer, in the presence of a polymerization initiator and a crosslinking agent, is polymerized crosslink to give N- vinylcarboxamide-based crosslinked copolymer resins, and oil absorbents its copolymer resin A method for producing an oil-absorbing agent . 5. The method for producing an oil absorbing agent according to claim 4, wherein an N-vinylcarboxylic acid amide-based crosslinked copolymer resin obtained by adding a resin particle dispersion stabilizer and polymerizing and crosslinking is used as the oil absorbing agent . The method for producing an oil absorbing agent according to claim 4, wherein the organic solvent is an alcohol or a hydrous alcohol. The method for producing an oil absorbing agent according to claim 4, wherein the organic solvent is a hydrous aliphatic ketone.