JP2015151336A - Thickener for mildly acidic cosmetic, and mildly acidic cosmetic containing the thickener - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cosmetic which does not cause creases even if containing a hydrophilic thickener, and have a refreshed feeling of use, in a mildly acidic cosmetic.SOLUTION: The invention provides: a thickener for a mildly acidic cosmetic, obtained by polymerizing a water-soluble unsaturated carboxylic acid monomer under the presence of a water-soluble crosslinker, and containing resin particles with a degree of neutralization of 50% or less and a median particle diameter of 5-30 μm; and the mildly acidic cosmetic containing the thickener.

Description

  The present invention relates to a thickener for weakly acidic cosmetics. Moreover, it is related with the weakly acidic cosmetics which mix | blend the said thickener.

  In medicinal creams, whitening creams, whitening emulsions, hair cosmetics, etc., as an acidic substance, anti-inflammatory agents, anti-acne agents (for example, salicylic acid, salicylic acid derivatives, retinoic acid, and derivatives thereof), acidic anti-aging agents (for example, ascorbine) Many products containing acid (vitamin C), etc., adjusted to a weak acidity of about pH 4-6 are manufactured. Even in such cosmetics, a refreshing tactile sensation is preferred, so a hydrophilic polymer having a carboxyl group such as a carboxyl vinyl polymer or an alkyl-modified carboxy vinyl polymer is used as a thickener, a dispersant or an emulsion stabilizer. Has been. However, these hydrophilic polymers show excellent thickening with a small amount of use, and a refreshing and fresh feeling of use can be obtained, but if a large amount is not used under acidic conditions, the desired thickening effect cannot be obtained, At that time, problems such as stickiness and twisting occur. In addition, from the viewpoint of salt thickening resistance, polysaccharide water-soluble polymers such as hydroxyethyl cellulose and xanthan gum may be used, but a refreshing and fresh tactile sensation cannot be obtained.

  The hydrophilic thickener described in Patent Document 1 enables the preparation of a lighter tactile cosmetic material that is lighter than the conventional carboxyvinyl polymer, but contains an acidic substance and is weakly acidic (for example, pH 4-6). ) Cosmetics are reduced in viscosity and stickiness, and a refreshing and fresh feeling of use cannot be obtained.

  Patent Document 2 proposes an emulsion composition in which tranexamic acid is used in combination with an alkyl-modified carboxyvinyl polymer, but in order to obtain a desired cream, it is necessary to increase the blending amount of the alkyl-modified carboxyvinyl polymer. It causes problems such as twisting.

  Patent Document 3 describes that a stable water-in-oil emulsion composition can be obtained by blending a salicylic acid derivative such as alkoxysalicylic acid together with salts and polyethylene glycol having a predetermined molecular weight. However, it is not satisfactory from the viewpoint of a refreshing and light feeling.

International publication 2012/160919 pamphlet JP 09-263510 A JP 2005-132807 A

  The object of the present invention is that the conventional carboxyvinyl polymer and the hydrophilic thickener described in Patent Document 1 cause problems such as stickiness and distortion, and there is no generation of distortion even in acidic cosmetics containing acidic substances. An object of the present invention is to provide a hydrophilic thickener capable of achieving a light and light feeling of use. Moreover, it is providing the cosmetics which have the said feeling of use.

  The present inventors have obtained resin particles having a neutralization degree of 50% or less and a median particle diameter of 5 to 30 μm obtained by polymerizing a water-soluble unsaturated carboxylic acid monomer in the presence of a water-soluble crosslinking agent. However, it has been found that it has an excellent thickening effect under weakly acidic conditions, and has been further improved to complete the present invention.

That is, the present invention includes, for example, the subject matters described in the following sections.
Item 1.
For weakly acidic cosmetics containing resin particles obtained by polymerizing a water-soluble unsaturated carboxylic acid monomer in the presence of a water-soluble crosslinking agent and having a neutralization degree of 50% or less and a median particle diameter of 5 to 30 μm Thickener.
Item 2.
The water-soluble crosslinking agent is at least selected from the group consisting of ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, N, N′-methylenebisacrylamide, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and water-soluble sucrose allyl ether. Item 1. The thickening agent for weakly acidic cosmetics according to Item 1, which is one type.
Item 3.
Item 2. The thickening agent for weakly acidic cosmetics according to Item 1, wherein the water-soluble crosslinking agent is water-soluble sucrose allyl ether.
Item 4.
Claims 1-3 wherein the water-soluble unsaturated carboxylic acid monomer is at least one selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid. The thickening agent for weakly acidic cosmetics according to any one of the above.
Item 5.
Item 5. A weakly acidic cosmetic comprising the thickener according to any one of Items 1 to 4.
Item 6.
Item 6. The weakly acidic cosmetic according to Item 5, further comprising an acidic substance.
Item 7.
Item 7. The weakly acidic cosmetic according to Item 5 or 6, further comprising a polysaccharide water-soluble polymer.

Term A.
Including resin particles having a neutralization degree of 50% or less, obtained by polymerizing a water-soluble unsaturated carboxylic acid monomer in the presence of a water-soluble crosslinking agent,
The resin particles are swollen and the median particle diameter is 40 to 300 μm.
Weakly acidic cosmetics.
Term B.
The water-soluble crosslinking agent is at least selected from the group consisting of ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, N, N′-methylenebisacrylamide, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and water-soluble sucrose allyl ether. The weakly acidic cosmetic according to Item A, which is one type.
Term C.
The weakly acidic cosmetic according to Item A, wherein the water-soluble crosslinking agent is a water-soluble sucrose allyl ether.
Term D.
Terms A to C, wherein the water-soluble unsaturated carboxylic acid monomer is at least one selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid The weakly acidic cosmetic according to any one of the above.

  In the present invention, a resin particle having a neutralization degree of 50% or less and a median particle diameter of 5 to 30 μm obtained by polymerizing a water-soluble unsaturated carboxylic acid monomer in the presence of a water-soluble crosslinking agent is used as a thickener. By using as, even in weakly acidic cosmetics, by adding a small amount of the thickening agent, it is possible to provide a cosmetic with a refreshing touch without stickiness.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The thickener for weakly acidic cosmetics of the present invention is obtained by polymerizing a water-soluble unsaturated carboxylic acid monomer in the presence of a water-soluble crosslinking agent, and has a neutralization degree of 50% or less and intermediate particles. It comprises resin particles having a diameter of 5 to 30 μm. The resin particles are preferably hydrophilic. And it is preferable that the thickener of this invention is hydrophilic.

  As described above, the thickener for weakly acidic cosmetics of the present invention includes a polymer (resin) of a water-soluble unsaturated carboxylic acid monomer that is cross-linked by a water-soluble cross-linking agent. The polymer can be obtained, for example, by a method including a step of polymerizing a water-soluble unsaturated carboxylic acid monomer by suspension polymerization in the presence of a water-soluble crosslinking agent. Among suspension polymerization methods, reverse-phase suspension polymerization method in which a polymerization reaction is carried out while dispersing water phase droplets containing a water-soluble unsaturated carboxylic acid monomer, a water-soluble crosslinking agent and water in a hydrophobic solvent. Is preferred.

The water-soluble unsaturated carboxylic acid monomer is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid. Of these, acrylic acid and methacrylic acid are preferable. A water-soluble unsaturated carboxylic acid monomer can be used individually by 1 type or in combination of 2 or more types.
In the present invention, the neutralization degree of the resulting polymer can be easily adjusted by neutralizing the carboxyl group of the water-soluble unsaturated carboxylic acid with an alkali. In the present invention, the degree of neutralization means the ratio of the number of moles of neutralized groups to the total number of moles of carboxyl groups of the water-soluble unsaturated carboxylic acid. Examples of the alkali used for neutralization include sodium hydroxide, potassium hydroxide, triethanolamine, diisopropylamine and the like. The neutralization method is not particularly limited, and examples thereof include a method of previously neutralizing a water-soluble unsaturated carboxylic acid monomer and a method of neutralizing a polymer obtained by polymerization.

  The degree of neutralization of a polymer (resin) obtained by polymerizing a water-soluble unsaturated carboxylic acid monomer in the presence of a water-soluble crosslinking agent is 50 from the viewpoint of compatibility with weakly acidic cosmetics and salt resistance. % Or less, preferably 45% or less, and more preferably 40% or less. When the degree of neutralization is greater than 50%, the viscosity of the weakly acidic cosmetic prepared by blending the polymer is low, and the practicality is poor.

  As a water-soluble crosslinking agent, Preferably, the compound which has 2 or more of a polymerizable unsaturated group and / or a reactive functional group is mentioned. The reactive functional group is a functional group that can react with the carboxyl group of the water-soluble unsaturated carboxylic acid monomer to form a crosslinked structure. Specific examples thereof include a glycidyl group. Examples of the water-soluble crosslinking agent having two or more glycidyl groups include ethylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether. Examples of water-soluble crosslinking agents having two or more polymerizable unsaturated groups include N, N'-methylenebisacrylamide, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and water-soluble sucrose allyl ether. Among these, water-soluble sucrose allyl ether is preferably used. In addition, a water-soluble crosslinking agent can be used individually by 1 type or in combination of 2 or more types.

  The degree of etherification of the water-soluble sucrose allyl ether is preferably 2.0 to 3.5, more preferably 2.2 to 3.2. When the degree of etherification of the water-soluble sucrose allyl ether is low, there is a tendency that the allyl group, which is a functional group involved in the cross-linking reaction, is insufficient and the cross-linking reaction is difficult to proceed effectively. If the degree of etherification of the water-soluble sucrose allyl ether is high, the solubility in water slightly decreases, so that the crosslinking reaction between the sucrose allyl ether and the water-soluble unsaturated carboxylic acid monomer proceeds slightly in the aqueous phase. It tends to be difficult. This degree of etherification is the average value of the molar ratio of allyl ether groups to sucrose. The degree of etherification can be calculated from the amount of acetic anhydride consumed by reacting the hydroxyl group remaining in sucrose allyl ether with acetic anhydride in pyridine.

  The water-soluble sucrose allyl ether can be obtained, for example, by adding sodium hydroxide as a catalyst to an aqueous sucrose solution to convert sucrose to alkaline sucrose and then adding allyl bromide dropwise to perform etherification. it can. At this time, a water-soluble sucrose allyl ether can be efficiently obtained by adjusting the amount of allyl bromide to a range of 2 to 6 times mol, preferably 2 to 5 times mol of sucrose. . The etherification reaction temperature is, for example, about 80 ° C. Usually, the reaction is completed in about 3 hours after the addition of allyl bromide. Water-soluble sucrose allyl ether can be recovered by adding alcohol to the aqueous phase separated from the reaction solution, filtering out precipitated salts, and distilling off excess alcohol and water.

  As the hydrophobic solvent used for the reverse phase suspension polymerization, for example, a petroleum hydrocarbon solvent selected from aliphatic hydrocarbons, alicyclic hydrocarbons and aromatic hydrocarbons is used. Examples of the aliphatic hydrocarbon include n-pentane, n-hexane, and n-heptane. Examples of the alicyclic hydrocarbon include cyclopentane, methylcyclopentane, cyclohexane, and methylcyclohexane. Aromatic hydrocarbons include benzene, toluene and xylene. In particular, at least one hydrophobic solvent selected from n-hexane, n-heptane, cyclohexane and toluene is suitably used as an industrial general-purpose solvent. The ratio of the hydrophobic solvent is, for example, 100 to 200 parts by mass with respect to 100 parts by mass of the aqueous phase containing the water-soluble unsaturated carboxylic acid monomer and the like.

  In the reverse phase suspension polymerization, the aqueous phase containing a water-soluble unsaturated carboxylic acid monomer or the like, or the hydrophobic solvent may contain other components such as a surfactant and a radical initiator.

  Surfactants are mainly used to stabilize the suspension during polymerization. The surfactant is not particularly limited as long as it is usually used in reverse phase suspension polymerization. Preferably, sorbitan fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, sorbitol fatty acid ester, modified polyethylene wax, modified polypropylene wax, polyvinyl alcohol, polyethylene oxide, cellulose ether (hydroxyethyl cellulose, ethyl cellulose, etc.), sodium alkylbenzene sulfonate, And one or more surfactants selected from polyoxyethylene alkylphenyl ether sulfates.

  The amount of the surfactant is preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass with respect to the water-soluble unsaturated carboxylic acid monomer. If the amount of the surfactant is small, there may be some problems in the stability of the suspension state during polymerization, and if the amount of the surfactant is large, it tends to be economically disadvantageous.

  The radical initiator is not particularly limited as long as it is used for normal radical polymerization, but potassium persulfate, ammonium persulfate, sodium persulfate, azo initiators, and the like are preferably used. For example, 2,2'-azobis (2-methylpropionamidine) dihydrochloride can be used as a radical initiator.

  The amount of the radical initiator is preferably 0.01 to 0.5 mass%, more preferably 0.02 to 0.2 mass%, based on the water-soluble unsaturated carboxylic acid monomer. When the amount of the radical initiator is within this range, the polymerization reaction can proceed more efficiently, and it is more excellent in thickening when the resulting polymer is used as a hydrophilic thickener.

  During the reverse phase suspension polymerization, the size of the droplets containing the water-soluble unsaturated carboxylic acid monomer and the like is closely related to the size of the polymer particles obtained. Depending on conditions such as reaction vessel and production scale, for example, when a 2 L flask is used as a reaction vessel, a polymer of an appropriate size can be obtained by carrying out reverse phase suspension polymerization at a stirring speed of 800 to 1000 rpm. It is likely that particles can be obtained. Thus, resin particles having a median particle diameter of 5 to 30 μm can be obtained by adjusting the stirring speed during the polymerization reaction and controlling the size of the polymer particles (resin particles). The polymer particles thus obtained have a spherical shape and are retained in aqueous liquids such as cosmetics, and therefore have a positive effect on various properties, touch and use feeling in cosmetics using them. it is conceivable that.

  The median particle diameter of the particles is the median particle diameter of the volume average particle diameter measured by a laser diffraction method in which the particles are dispersed in n-hexane. For example, SALD-2000A (manufactured by Shimadzu Corporation) can be used as a measuring device (laser diffraction particle size distribution measuring device) by this method.

  In the present invention, the median particle diameter of the particles is 5 to 30 μm as described above, preferably 5 to 25 μm, and more preferably 6 to 20 μm. When the median particle diameter is not within the above range, the feel (soft and light feel) when a weakly acidic cosmetic comprising the particles is applied to the skin is inferior, and twisting tends to occur.

  Other conditions for the polymerization reaction, such as the amount of radical initiator, polymerization reaction temperature, reaction time, etc., are also adjusted as appropriate. The polymerization reaction temperature is, for example, 50 to 80 ° C., and the reaction time is, for example, 30 minutes to 3 hours. For example, when a 2 L flask is used as a reaction vessel, the polymerization temperature can be started by adjusting the bath temperature to 60 ° C. In this case, the start of the polymerization reaction can be confirmed from the fact that the temperature in the reaction vessel rises to about 70 ° C. by the polymerization heat. Thereafter, the polymerization reaction is usually completed by conducting an aging reaction for about 30 minutes to 3 hours. If the aging time is shorter than that, the reaction may not be completed sufficiently, and the remaining water-soluble unsaturated carboxylic acid monomer may increase. After the aging reaction, the product can be obtained by raising the bath temperature and distilling off the water and the petroleum hydrocarbon solvent in the reaction vessel.

  The thick acid thickener for weak acid cosmetics of the present invention may contain a known water-soluble thickener other than the resin particles as long as the effects of the present invention are not impaired. Examples of such water-soluble thickeners include polysaccharide water-soluble polymers such as hydroxyethyl cellulose and xanthan gum, carboxyvinyl polymers, and alkyl-modified carboxyvinyl polymers. In addition, it is preferable that the thickener for weakly acidic cosmetics of this invention consists of the said resin particle.

  The pH of the 0.5 mass% aqueous solution of the thickener for weakly acidic cosmetics of this invention is preferably 4-7, and more preferably 4.5-6.5. Moreover, it is preferable that the viscosity of the said 0.5 mass% aqueous solution is 10,000-20,000 (mPa * s), and it is more preferable that it is 12,000-19,000 (mPa * s).

  Moreover, as above-mentioned, this invention also includes the weak acid cosmetics which mix | blend the said thickener for weak acid cosmetics. The weakly acidic cosmetic may further contain an acidic substance.

  In the present invention, the weakly acidic cosmetic is a cosmetic having a pH of 4 or more and less than 7, preferably a cosmetic having a pH of 4 to 6.5, and more preferably a cosmetic having a pH of 4 to 6. Moreover, in this invention, it is preferable that the viscosity of weakly acidic cosmetics is 12,000-20,000 (mPa * s).

  In addition, pH and the viscosity in the 0.5 mass% aqueous solution of the said thick acid cosmetics for weak acids, and the weak acid cosmetics of this invention are all measured by the following method.

  That is, the pH is a value measured at 25 ° C. using a pH meter. For example, HORIBA D-51 (Horiba, Ltd.) can be used as the pH meter. The viscosity was measured 1 minute after starting the rotation of the rotor at 25 ° C. using a BH type rotational viscometer (rotor No. 6 or 7 was used and the rotation speed was 20 rotations per minute). Value.

  When the resin particles contained in the thick acid cosmetic thickener of the present invention are blended into the weak acid cosmetic, the resin particles absorb water and swell. About 8-10 times. The median particle diameter of the absorbed resin particles is preferably about 40 to 300 μm, and more preferably about 50 to 250 μm. In addition, the said median particle diameter is a median particle diameter of the volume average particle diameter measured by the laser diffraction method. For example, SALD-2000A (manufactured by Shimadzu Corporation) can be used as a measuring device (laser diffraction particle size distribution measuring device) by this method.

  The acidic substance used in the present invention may be any component that is acidic in an aqueous solution and is known to be used in cosmetics. For example, known anti-inflammatory agents, humectants, keratolytic agents, astringents, acidic anti-aging agents, anti-fat deposits, whitening agents, anti-acne agents, etc., that exhibit acidity in aqueous solutions.

  Specifically, lactic acid, glycolic acid, malic acid, citric acid, tartaric acid, gluconic acid, mandelic acid, benzylic acid, azelaic acid, α-lipoic acid, salicylic acid, α-hydroxybutyric acid, β-hydroxybutyric acid, aspartic acid, Examples thereof include glutamic acid, ascorbic acid (vitamin C)), ascorbic acid glucoside, salicylic acid, salicylic acid glycol, retinoic acid and the like.

  Although the content of the acidic substance in the weakly acidic cosmetic of the present invention varies depending on the components contained, it is preferably contained in an amount of 0.5 to 5% by mass with respect to the total components.

  The type of cosmetic according to the present embodiment is not particularly limited. For example, medicated cream, lotion, milky lotion, serum, cream, cream pack, massage cream, cleansing cream, cleansing gel, gel cream, facial cleansing foam, moisturizing Gel, hair setting gel, sunscreen, styling gel, eyeliner, mascara, lipstick and foundation. Moreover, as other components contained in the cosmetics of the present invention, as long as the effects of the present invention are not impaired, there are no particular limitations as long as they are known components blended in cosmetics, for example, water, powder components, Liquid oil, solid oil, wax, hydrocarbon oil, higher fatty acid, higher alcohol, ester oil, silicone oil, anionic surfactant, cationic surfactant, amphoteric surfactant, nonionic surfactant, humectant, water-soluble Polymer, film agent, UV absorber, sequestering agent, lower alcohol, polyhydric alcohol, sugar, amino acid, organic amine, polymer emulsion, pH adjuster, skin nutrient, vitamin, antioxidant, antioxidant assistant Agents, fragrances and the like.

  When the cosmetics according to this embodiment are used as cream cosmetics such as creams, cream packs, massage creams and cleansing creams, or gel cosmetics such as cleansing gels, gel creams, moisturizing gels, hair setting gels and styling gels Even if it is blended at a high concentration, a refreshing feeling and lightness are imparted without causing twisting, and the merit is particularly great.

  For example, emulsions and creams that are oil-in-water emulsified cosmetics, in addition to oily ingredients, water and thickeners for weakly acidic cosmetics of the present invention, if necessary, active substances such as acidic substances and plant extracts, It may be composed of components such as surfactants, chelating agents (such as sodium edetate), preservatives, and fragrances. Generally, an oil-in-water emulsified cosmetic is produced by a step of heating and dissolving a water phase and an oil phase at around 70 ° C., emulsifying with a homomixer, and then cooling with stirring. The thick acid cosmetic thickener of the present invention is considered to function as a rheology control agent and an emulsion stabilizer for these products.

  The blending amount of the thick acid cosmetic thickener in the weak acid cosmetic of the present invention can be appropriately set according to the type of the cosmetic and the required viscosity. For example, it may be 0.3-2% by mass. In addition, the compounding quantity of the thick acid agent for weakly acidic cosmetics in weakly acidic cosmetics is the addition amount of the thickener in normal cosmetics, for example, is 0.1-0. 3% by mass, and about 0.2-2% by mass in a general cream. This is because generally 1% by mass or more tends to cause stickiness and twist. However, in the weakly acidic cosmetic of the present invention, about 1 to 2% by mass of the thickener for weakly acidic cosmetics can be preferably blended from the viewpoint of obtaining a desired viscosity.

  Among weakly acidic cosmetics, an emulsion and cream that are oil-in-water emulsified cosmetics will be described below.

  The oil component is not particularly limited, but may be natural oil, silicone oil, ester oil, or the like in consideration of the texture to the skin, familiarity, appearance, slipperiness, and the like.

  Examples of natural oils include paraffinic hydrocarbons such as liquid paraffin, olive oil, macadamia nut oil, castor oil, jojoba oil, orange luffy oil, beeswax, lanolin, mineral oil, and squalane.

  Examples of the silicone oil include modified silicone oils such as methylpolysiloxane, methylphenylpolysiloxane, cyclic methylsiloxane, and silicone polyether copolymer.

  Examples of the ester oil include various fatty acid esters. For example, octyldodecyl ester of each fatty acid such as oleic acid, erucic acid, myristic acid, ricinoleic acid is preferable.

  These oily components may be used alone or in combination of two or more.

  A whitening agent and a humectant may be blended. In addition, the component which shows acidity in aqueous solution in a whitening agent and a moisturizer is an acidic substance.

  As the whitening agent, sodium ascorbate, ascorbic acid glucoside, ascorbic acid 2 glucoside and the like are used.

  The humectant is suitably selected from glycerin, propylene glycol, sorbit, polyethylene glycol, dipropylene glycol, 1,3-butylene glycol, diglycerin, mannitol, POE methyl glycoside, and the like.

  As the surfactant, nonionic glycerin monostearate, POE sorbitan fatty acid ester, sorbitan fatty acid ester, and the like are often used. However, anionic, cationic or amphoteric surfactants can also be used.

  Further, in the case where the weakly acidic cosmetic is a gel-type cosmetic such as a moisturizing gel and a hair setting gel, for example, water, a moisturizing agent, and a drug such as a hair setting agent if necessary, and a thickener for the weakly acidic cosmetic Containing. The amount of the thickener is preferably 0.3 to 2% by mass based on the mass of the gel cosmetic.

  Further, the weakly acidic cosmetic of the present invention may further contain a hydrophilic thickener as long as the effects of the present invention are not impaired. Examples of such hydrophilic thickeners include polysaccharide water-soluble polymers such as hydroxyethyl cellulose and xanthan gum, carboxyvinyl polymers, and alkyl-modified carboxyvinyl polymers. Among these, xanthan gum is particularly preferable because the thickening effect is further enhanced by using it in combination with the thick acid cosmetic thickener of the present invention. In addition, these hydrophilic thickener further mix | blended with weak acidic cosmetics can be used individually by 1 type or in combination of 2 or more types.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

<Synthesis of water-soluble sucrose allyl ether>
(Production Example 1)
A stirrer, a reflux condenser, and a dropping funnel were attached to a 1000 mL separable flask. In this separable flask, 48 g (1.2 mol) of sodium hydroxide was dissolved in 144 g of water. 136.8 g (0.4 mol) of sucrose was added thereto, and the mixture was stirred at 70 to 85 ° C. for 120 minutes to prepare an alkaline sucrose aqueous solution. To this alkaline sucrose aqueous solution, 145.2 g (1.2 mol) of allyl bromide was added dropwise at 70 to 85 ° C. over 1.5 hours, and then aged at 80 ° C. for 3 hours to obtain sucrose. Was allyl etherified. After cooling, 440 g of water was added, and excess oil was separated with a separatory funnel to obtain a crude sucrose allyl ether aqueous solution. After adjusting the pH to 6-8 by adding hydrochloric acid to this crude sucrose allyl ether aqueous solution, water was removed using a rotary evaporator until the mass of the aqueous solution reached 480 g. Then, 200 g of ethanol was added to precipitate a by-product salt such as sodium bromide, and the precipitate was removed from the aqueous solution by filtration. Further, excess water was removed from the aqueous solution by using an evaporator to obtain 166 g of purified water-soluble sucrose allyl ether having a degree of etherification of 2.4.

<Synthesis of resin (polymer of water-soluble unsaturated carboxylic acid monomer crosslinked by water-soluble crosslinking agent)>
(Production Example 2)
A 500 mL separable flask was equipped with a stirrer, a reflux condenser, and a dropping funnel. In this separable flask, 72 g of acrylic acid and water were put to prepare 90 g of an 80% by mass acrylic acid aqueous solution. Furthermore, 56 g of ion-exchanged water, 0.023 g of the water-soluble sucrose allyl ether of Production Example 1 as a crosslinking agent (0.25% by mass with respect to the aqueous acrylic acid solution), and 2,2′-azobis (2 -Methylpropionamidine) dihydrochloride (V-50 manufactured by Wako Pure Chemical Industries, Ltd.) (0.04 g) was added to prepare a water-soluble unsaturated carboxylic acid monomer aqueous solution.

  Separately, 330 g of n-heptane was put into a 2 L separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a nitrogen gas introduction tube, and sorbitan monostearate (NOF CORPORATION) as a surfactant. (Nonion SP-60R, 2.7 g) was added, and this was dispersed and dissolved in n-heptane. The water-soluble unsaturated carboxylic acid monomer aqueous solution prepared previously was added there. In order to remove oxygen present in the atmosphere, raw materials and solvent in the reaction vessel, nitrogen gas was blown into the solution to replace the system with nitrogen, while the bath temperature was maintained at 60 ° C. and the stirring rate was 1000. Polymerization was carried out by the reverse phase suspension polymerization method over 1 hour with stirring at rotation / min. After completion of the polymerization, water and n-heptane were distilled off to obtain a polymer of acrylic acid and its sodium salt, which was crosslinked with water-soluble sucrose allyl ether. 62 g of powder was obtained (hereinafter, this resin is referred to as “resin A”).

(Production Example 3)
A 500 mL separable flask was equipped with a stirrer, a reflux condenser, and a dropping funnel. In this separable flask, 72 g of acrylic acid and water were put to prepare 90 g of an 80% by mass acrylic acid aqueous solution. While cooling the aqueous acrylic acid solution, 27 g of a 30% by weight aqueous sodium hydroxide solution was added dropwise to neutralize the aqueous solution. Furthermore, 56 g of ion-exchanged water, 0.023 g of the water-soluble sucrose allyl ether of Production Example 1 as a crosslinking agent (0.25% by mass with respect to the aqueous acrylic acid solution), and 2,2′-azobis (2 -Methylpropionamidine) dihydrochloride (V-50 manufactured by Wako Pure Chemical Industries, Ltd.) (0.04 g) was added to prepare a water-soluble unsaturated carboxylic acid monomer aqueous solution.

  Separately, 330 g of n-heptane was put into a 2 L separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a nitrogen gas introduction tube, and sorbitan monostearate (NOF CORPORATION) as a surfactant. (Nonion SP-60R, 2.7 g) was added, and this was dispersed and dissolved in n-heptane. The water-soluble ethylenically unsaturated monomer aqueous solution prepared previously was added there. In order to remove oxygen present in the atmosphere, raw materials and solvent in the reaction vessel, nitrogen gas was blown into the solution to replace the system with nitrogen, while the bath temperature was maintained at 60 ° C. and the stirring rate was 1000. Polymerization was carried out by the reverse phase suspension polymerization method over 1 hour with stirring at rotation / min. After completion of the polymerization, water and n-heptane were distilled off to obtain a polymer of acrylic acid and its sodium salt, which was a polymer crosslinked with water-soluble sucrose allyl ether. 80 g of powder was obtained (hereinafter, the resin is referred to as Resin B).

(Production Example 4)
90 g of resin powder having a neutralization degree of 40% was obtained in the same manner as in Production Example 3 except that the 30% by mass sodium hydroxide aqueous solution was changed to 54 g (hereinafter referred to as resin C).

(Production Example 5)
90 g of resin powder having a neutralization degree of 40% was obtained in the same manner as in Production Example 4 except that the stirring rotation speed was changed to 800 rotations (hereinafter, this resin is referred to as “resin D”).

(Production Example 6)
90 g of resin powder having a neutralization degree of 40% was obtained in the same manner as in Production Example 4 except that the stirring rotation speed was changed to 600 rotations (hereinafter, this resin is referred to as “resin E”).

(Production Example 7)
Except for changing the 30% by mass aqueous sodium hydroxide solution to 94 g, 102 g of resin powder having a neutralization degree of 70% was obtained in the same manner as in Production Example 3 (hereinafter, the resin is referred to as Resin F).

<Synthesis of carboxyvinyl polymer>
(Production Example 8)
In a 500 mL four-necked flask equipped with a stirrer, thermometer, nitrogen blowing tube and cooling tube, 45 g (0.625 mol) of acrylic acid, 0.27 g of pentaerythritol allyl ether, 150 g of normal hexane and 2,2 ′ -A reaction liquid was prepared by charging 0.081 g (0.00035 mol) of azobismethylisobutyrate. After stirring the reaction liquid and mixing the respective raw materials uniformly, nitrogen gas was blown into the solution in order to remove oxygen present in the atmosphere of the reaction vessel, the raw materials and the solvent. Next, the reaction solution was kept at 60 to 65 ° C. for 4 hours under a nitrogen atmosphere. After completion of the reaction, the resulting slurry was heated to 90 ° C. to distill off n-hexane, and further dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 42 g of white fine powdery carboxyvinyl polymer powder. Got.

<Characteristic evaluation of resin and carboxyvinyl polymer>
<Measurement of median particle size>
Each resin obtained in Production Examples 2 to 7 and the carboxyvinyl polymer powder obtained in Production Example 8 were dispersed in n-hexane, respectively, and volume was measured using a Shimadzu laser particle size measuring device (SALD2000 flow cell used). The median particle size of the average particle size was measured. The results are shown in Table 1.

<Measurement of 0.5 mass% aqueous liquid viscosity>
Each resin and carboxyvinyl polymer were mixed with water to prepare respective aqueous liquids (concentration 0.5% by mass). When the resin contains acrylic acid sodium salt as a monomer unit, the mass% of the resin was calculated based on the mass of the acrylic acid monomer unit. The pH of each aqueous liquid containing resins B to F was 4.8 to 7.0. About each aqueous liquid containing resin A and a carboxy vinyl polymer, while adjusting pH to 6.0 using a predetermined amount of 6 mass% sodium hydroxide aqueous solution as a neutralizing agent, the resin concentration is 0.5 mass%. It was. The viscosity of each 0.5 mass% aqueous liquid was measured using a BH type rotational viscometer. The rotation speed of the spindle rotor was set to 20 rotations per minute, and the viscosity value one minute after starting the rotation of the rotor at 25 ° C. was read. Resins A to F are rotor nos. 6. Carboxyvinyl polymer is rotor no. 7 was used. The results are shown in Table 1.

<Adjustment of cosmetics>
<Whitening cream A>
Example 1
The following oil components 1 to 4 are mixed, resin A is added thereto and dispersed with a homomixer, and a uniform mixed solution obtained by dissolving components 6 to 10 in water is added, followed by emulsification with a homomixer (13000 rpm). Whitening cream A-1 was obtained.

Oil phase Liquid paraffin 5%
2. Squalane 5%
3. Isopropyl palmitate 5%
4). Tri (capryl / capric acid) glyceryl 5%
5. Resin A 1.5%
Aqueous phase 6. Polyoxyethylene glyceryl isostearate (20E.O.) 3%
7). Ascorbic acid glucoside 1.5%
8). Phenoxyethanol 0.5%
9.6% sodium hydroxide Purified water residue

(Example 2)
A whitening cream A-2 was prepared in the same manner as in Example 1 except that the resin A was changed to the resin B.

(Example 3)
A whitening cream A-3 was prepared in the same manner as in Example 1 except that the resin A was changed to the resin C.

Example 4
A whitening cream A-4 was prepared in the same manner as in Example 1 except that the resin A was changed to the resin D.

(Comparative Example 1)
A whitening cream A-5 was prepared in the same manner as in Example 1 except that the resin A was changed to the resin E.

(Comparative Example 2)
A whitening cream A-6 was prepared in the same manner as in Example 1 except that the resin A was changed to the resin F.

(Comparative Example 3)
A whitening cream A-7 was prepared in the same manner as in Example 1 except that the resin A was changed to carboxyvinyl polymer.

<Whitening cream B>
(Example 5)
The following oil components 1 to 4 are mixed, and resin C is added thereto and dispersed with a homomixer. Further, a uniform mixed solution obtained by dissolving components 6 to 11 in water is added and emulsified with a homomixer (13000 rpm). Whitening cream B-1 was obtained.

Oil phase Liquid paraffin 5%
2. Squalane 5%
3. Isopropyl palmitate 5%
4). Tri (capryl / capric acid) glyceryl 5%
5. Resin C 1%
Aqueous phase 6. Polyoxyethylene glyceryl isostearate (20E.O.) 3%
7). Ascorbic acid glucoside 1.5%
8). Xanthan gum 0.5%
9. Phenoxyethanol 0.5%
10.6% sodium hydroxide appropriate amount11. Purified water residue

(Comparative Example 4)
In Example 5, a whitening cream B-2 was obtained in the same manner as in Example 5 except that the resin C was not used.

<Medicated cream>
(Example 6)
The following oil components 1 to 4 are mixed, resin C is added thereto and dispersed with a homomixer, and a uniform mixed solution obtained by dissolving components 6 to 10 in water is added, followed by emulsification with a homomixer (13000 rpm). I got a medicated cream.

Oil phase Liquid paraffin 5%
2. Squalane 5%
3. Isopropyl palmitate 5%
4). Tri (capryl / capric acid) glyceryl 5%
5. Resin C 1.5%
Aqueous phase 6. Glycerin 5%
7. 1,3-butylene glycol 5%
8). Polyoxyethylene glyceryl isostearate (20E.O.) 3%
9. Glycol salicylate 1.5%
10. Phenoxyethanol 0.5%
11.6% sodium hydroxide appropriate amount 12. Purified water residue

(Comparative Example 5)
A medicated cream was prepared in the same manner as in Example 6 except that the resin C was changed to the resin F in Example 6.

(Comparative Example 6)
A medicated cream was prepared in the same manner as in Example 6 except that the resin C was changed to carboxyvinyl polymer in Example 6.

<Characteristic evaluation of cosmetics>
About the cosmetics obtained in Examples 1-6 and Comparative Examples 1-6, pH, a viscosity, tactile sensation, and twist property were evaluated by the following methods. The results are shown in Table 2.

<pH>
It measured using pH meter HORIBA D-51 (Horiba, Ltd.) at 25 degreeC.

<viscosity>
Measurement was performed using a BH type rotational viscometer. The rotation speed of the spindle rotor was set to 20 rotations per minute, and the viscosity value one minute after starting the rotation of the rotor at 25 ° C. was read. The viscosity of 1000 (mPa · s) or less is the rotor No. 2, viscosity 8000-20000 (mPa · s) is the rotor No. 6 was used.

<Tactile sense>
The tactile sensation was evaluated as follows by 5 males and 5 females (10 in total). An appropriate amount of cosmetic was applied to the back of the hand, and the refreshing feeling and lightness when stretched with fingers were evaluated as the texture based on the following criteria.

Evaluation criteria (circle): There were 8 or more testers who evaluated refreshing feeling and lightness as good.
X: Seven or fewer testers evaluated that the refreshing feeling and lightness were good.

<Laterity>
The tactile sensation was evaluated as follows by 5 males and 5 females (10 in total). When 0.5 g of cosmetic material was taken on the skin and applied to the forearm with a coating time of 1 minute, the occurrence of twists (aggregates) was confirmed.

Evaluation criteria x: 9 or more out of 10 people evaluated that there was a large amount of aggregates.
Δ: 2 to 8 out of 10 people evaluated that there was a slight agglomeration.
○: Nine or more out of 10 people evaluated that there was almost no aggregate.

  As shown in Table 2, according to Examples 1 to 4 and Example 6 using resins A to D, even in cosmetics containing an acidic substance, a good cosmetic that has a light, light touch and no twist. was gotten. These specific resins (resins with a degree of neutralization of 50% or less obtained by polymerization in the presence of a water-soluble crosslinking agent and a median particle size of 5 to 30 μm) are used as hydrophilic thickeners, particularly in acidic cosmetics. It turned out to be suitable for.

  Furthermore, according to Example 5, a thickening synergistic effect was recognized by using the specific resin and xanthan gum together.

Claims (7)

  For weakly acidic cosmetics containing resin particles obtained by polymerizing a water-soluble unsaturated carboxylic acid monomer in the presence of a water-soluble crosslinking agent and having a neutralization degree of 50% or less and a median particle diameter of 5 to 30 μm Thickener.   The water-soluble crosslinking agent is at least selected from the group consisting of ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, N, N′-methylenebisacrylamide, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and water-soluble sucrose allyl ether. The thickener for weakly acidic cosmetics according to claim 1, which is one type.   The thickener for weakly acidic cosmetics according to claim 1, wherein the water-soluble crosslinking agent is water-soluble sucrose allyl ether.   The water-soluble unsaturated carboxylic acid monomer is at least one selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and itaconic acid. 4. The thickener for weakly acidic cosmetics according to any one of 3.   A weakly acidic cosmetic comprising the thickener according to any one of claims 1 to 4.   Furthermore, the weakly acidic cosmetics of Claim 5 containing an acidic substance.   The weakly acidic cosmetic according to claim 5 or 6, further comprising a polysaccharide water-soluble polymer.