JP2022090046A - Composition having upper critical solution temperature - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition having an upper critical solution temperature suitable for use as a cosmetic or skin external preparation, or having a temperature at which the solubility thereof rapidly increases.

SOLUTION: According to the present invention, after determination of the upper critical solution temperatures of aqueous solutions of six different copolymers of acrylamide and acrylonitrile with different monomer mass-feeding ratios, a surfactant, such as an anionic surfactant, was added to the aqueous solutions containing the respective copolymers. As a result, the mixed solutions of copolymers showed lowered upper limit critical solution temperatures, respectively.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to the use of a composition having an upper critical solution temperature containing a copolymer of acrylamide and acrylonitrile, and more particularly to the above composition for use as a cosmetic or an external preparation for the skin.

Cosmetics are often required to have the opposite performance, such as smoothness and close contact, and long-lasting makeup that is easy to remove. For example, polymer polymers used in film mascara are required to exhibit their functions in response to a specific stimulus, such as not falling off with water but falling off with hot water.

As the above stimulus, pH, light and the like are known in addition to temperature, but poly (N-isopropylacrylamide) is well known as a temperature-responsive polymer that causes a structural change depending on temperature, and poly (N-acryloyl) is known. There are also reports on glycinamide) and the like (see, for example, Non-Patent Document 1). Although studies have been conducted on the formulation of such temperature-responsive polymers in cosmetics, it cannot be said that their application to cosmetics is being promoted. One of the reasons is that the properties change due to the temperature stimulus even in situations where the expression of function is not desired. For example, in a product containing a temperature-responsive polymer, it is said that the stability of quality may be impaired due to the change in properties in a high temperature environment.

On the other hand, polyacrylamide is dissolved in water, polyacrylonitrile is dissolved only in polar solvents such as N, N-dimethylformamide (DMF) and dimethylsulfoxide (DMSO), and DMSO- _H2O is freely mixed. , The solubility of the copolymer of acrylamide (AAm) and acrylonitrile (AN) has been investigated, and the synthesis of the copolymer has been carried out in the range of AAm / AN composition ratio = 0/100 to 100/0. The composition of the obtained copolymer is analyzed by an infrared and ultraviolet absorption spectrum method, a specific gravity method, etc., and its solubility in various solvents is measured (see, for example, Non-Patent Document 2). It has also been reported that the aqueous solution of the copolymer of acrylamide (AAm) and acrylonitrile (AN) has an upper limit critical solution temperature, and the upper limit critical solution temperature can be adjusted by changing the AAm / AN composition ratio. (See, for example, Non-Patent Document 3).

On the other hand, when using cosmetics and external skin preparations, it is often necessary to wash off after a certain period of time in consideration of the duration of effect and purpose of use, but regarding the temperature of water suitable for washing the face. Has various opinions. For example, if you wash your face with hot water at around 40 ° C, which is slightly higher than the skin temperature, pores will open and you will be able to remove cosmetics etc. It is said that water may be lost from the skin. On the other hand, washing the face with cold water can tighten the pores, but it is said that the pores may remain clogged with cosmetics or the like. In addition, it may be necessary to maintain or easily remove cosmetics and external skin preparations even in special environments such as tropical areas, cold regions, and underwater, and the compositions used as cosmetics and external skin preparations are wide-ranging. It is also required to be able to cope in the temperature range.

Howard C. H., Norman W. S., Polymer letters vol.2 (1964) Takahashi et al., Industrial Chemistry Magazine Vol. 70, No. 6 (1967), pp. 988-992 Seuring et al., Macromolecules 2012, 45, 3910-3918

An object of the present invention is to provide a composition having an upper critical solution temperature suitable for use as a cosmetic or an external preparation for skin.

The present inventors use acrylamide (AAm) and acrylonitrile (AN) as monomers, and by variously changing the monomer mass charging ratio ([(AAm) :( AN)]), acrylamide and acrylonitrile can be combined. Six kinds of random copolymers ([poly (AAm-co-AN)]) were synthesized by free radical polymerization. The upper limit critical solution temperature of each copolymer-containing aqueous solution is measured by dissolving these six types of copolymers in water, lowering and raising the temperature of each copolymer-containing aqueous solution, and measuring the change in light transmittance. It was confirmed that the upper limit critical solution temperature of the copolymer-containing aqueous solution increased as the ratio of AN in [(AAm): (AN)] increased. Next, it was found that when a surfactant was added to the above-mentioned 6 kinds of [poly (AAm-co-AN)] -containing aqueous solutions, the upper limit critical solution temperature of each copolymer-containing aqueous solution was lowered. Therefore, it was confirmed how much the upper limit critical solution temperature was lowered when each copolymer was dissolved in the surfactant-containing aqueous solution as compared with the case where each copolymer was dissolved in the aqueous solution.

Next, 6 types of [poly (AAm-co-AN)] were synthesized by Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization, and each copolymer was dissolved in water to contain each copolymer. The upper limit critical solution temperature of each copolymer-containing aqueous solution was determined by lowering and raising the temperature of the aqueous solution and measuring the change in the light transmittance. It was found that the [poly (AAm-co-AN)] -containing aqueous solution synthesized by RAFT polymerization had a large change in transmittance per unit temperature in the aqueous solution as compared with the case where it was synthesized by free radical polymerization, and therefore the aqueous solution. It was confirmed that the sensitivity of the temperature response of the above was increased, and the present invention was completed.

That is, the present invention is as specified by the following matters.
[1] A composition having an upper critical solution temperature containing a copolymer of acrylamide and acrylonitrile or a temperature at which the solubility rapidly increases for use as a cosmetic or a skin external preparation.
[2] The composition according to the above [1], wherein the copolymer has a monomer mass charging ratio of acrylamide: acrylonitrile = 77.5: 22.5 to 85:15.
[3] The composition according to the above [1] or [2], wherein the copolymer has a weight average molecular weight of 8,000 to 200,000.
[4] The composition according to any one of the above [1] to [3], wherein the copolymer is a random copolymer.
[5] The composition according to the above [4], wherein the random copolymer is a random copolymer synthesized by free radical polymerization.
[6] The composition according to the above [4], wherein the random copolymer is a random copolymer synthesized by reversible addition-fragmentation chain transfer polymerization.
[7] The composition according to any one of the above [1] to [6], which has temperature sensitivity when 1 to 20 mM of sodium dodecyl sulfate is added.
[8] The above-mentioned [6] or [7], wherein the maximum value of the differential curve of the light transmittance-temperature curve in a 1 w / v% aqueous solution containing no surfactant is 50 d% T / dT or more. Composition.
[9] The feature is that the surfactant is brought into contact with a cosmetic or skin external preparation comprising a composition having an upper limit critical solution temperature containing a copolymer of acrylamide and acrylonitrile or a temperature at which the solubility rapidly increases. A method of lowering the upper limit critical solution temperature or the temperature at which the solubility rises sharply.
Further, as another aspect of the present invention, [10] a cosmetic or a skin external preparation having an upper limit critical solution temperature containing a copolymer of acrylamide and acrylonitrile, or a temperature at which the solubility rapidly increases, [11] cosmetic. Use of a composition having an upper critical solution temperature containing a copolymer of acrylamide and acrylonitrile, or a temperature at which the solubility increases rapidly, for producing a drug or an external preparation for skin, [12] cosmetic ingredient or skin. A method for producing a cosmetic or skin external preparation having an upper limit critical solution temperature characterized by blending a copolymer of acrylamide and acrylonitrile as an external preparation component or a temperature at which the solubility rapidly increases, [13]. The present invention relates to a composition containing a copolymer of acrylamide and acrylonitrile having an upper limit critical solution temperature or a temperature at which the solubility increases rapidly for use as a cosmetic or an external preparation for skin.

The composition for use as the cosmetic or skin external preparation of the present invention is a cosmetic or skin external preparation containing a polymer of acrylamide and acrylonitrile having an upper critical solution temperature and a cosmetic component or a skin external preparation component. Since it has an upper limit critical solution temperature or a temperature at which the solubility rises sharply, it cannot be removed (dissolved) by water or sweat, but can be easily removed (dissolved) by warm water. Further, according to the composition of the present invention, the upper limit critical solution temperature or the temperature at which the solubility rapidly increases is lowered by adding a surfactant to the aqueous solution in which the copolymer of acrylamide and acrylonitrile is dissolved. Therefore, it is possible to provide cosmetics and skin external preparations having a high cleaning effect according to the application and the operating temperature environment. For example, when washed with water at a specific temperature, it does not show solubility, but the interface. When the face is washed with water using a cleaning agent containing an activator, the upper limit critical solution temperature or the temperature at which the solubility rises sharply becomes lower, so that the polymer in the composition is contained even at the above specific temperature. Since it dissolves easily and the face can be washed at a lower temperature than before, the burden on the skin is reduced.

Further, according to the composition of the present invention, by adding a salt (for example, NaCl) contained in sweat to an aqueous solution in which a copolymer of acrylamide and acrylonitrile is dissolved, the upper critical solution temperature or abruptly Since the temperature at which the solubility increases does not decrease, the cosmetics are not removed by sweat, and the cosmetics and external preparations for skin can be effectively removed only when the user wants to wash.

Further, when a random copolymer synthesized by RAFT polymerization is used instead of free radical polymerization as the copolymer of acrylamide and acrylonitrile in the composition of the present invention, the sensitivity of the temperature response of the composition solution becomes high. That is, since the change in the transmittance of the composition solution per unit temperature becomes large, even when the concentration of the surfactant in the water used for washing is very low or the surfactant is not contained, cosmetics and the like can be used. The cleaning effect is remarkably enhanced by being easily melted at a specific narrow range of temperatures.

Random copolymers (poly (AAm-co-AN)) with different monomer mass charging ratios of acrylamide and acrylonitrile ([(AAm): (AN)]) (hereinafter, simply [poly (AAm-co-AN)] (Also also referred to as), and for each of the six types of [poly (AAm-co-AN)] (F1 to F6) synthesized by free radical polymerization, the light transmittance (vertical axis) of each 1 w / v% aqueous solution. And the temperature of the solution (horizontal axis) are plotted in a graph. For F1 to F6, a graph is shown in which the light transmittance and the temperature of the solution are plotted for a mixed solution in which a final concentration of 100 mM sodium dodecyl sulfate (SDS) is added to each 1 w / v% aqueous solution. A 1 w / v% aqueous solution of [Poly (AAm-co-AN)] [82.5: 17.5] (F3) synthesized by free radical polymerization at a final concentration of 5 mM, 10 mM, 15 mM, 20 mM, 30 mM and 100 mM. The graph which plotted the light transmittance of each mixed solution to which SDS was added and the temperature of a solution is shown. For F1 to F6, the graph which plotted the light transmittance and the temperature of the mixed solution which added the cetyltrimethylammonium chloride (CTAC) of the final concentration of 100 mM to each 1w / v% aqueous solution is shown. For F1 to F6, a graph showing the light transmittance and the temperature of the mixed solution in which NaCl with a final concentration of 100 mM is added to each 1 w / v% aqueous solution is plotted. [Poly (AAm-co-AN)] [82.5: 17.5] synthesized by RAFT polymerization, 1w / v% aqueous solution and 0.1w of the copolymer of R1 having Mw of 12400. The graphs (A) and (A1) plotting the transmittance and the temperature of the solution for the / v% aqueous solution and their differential curves (a) and (a1) are shown. Further, graphs (F) and (F1) plotting the transmittance and the temperature of the solution for a 1 w / v% aqueous solution and a 0.1 w / v% aqueous solution of the F1 copolymer, and their differential curves (f). And (f1). A 1w / v% aqueous solution of each of four types of [Poly (AAm-co-AN)] [82.5: 17.5] (R1 to R4) synthesized by RAFT polymerization and having different weight average molecular weights (Mw). Graphs (A) to (D) plotting the light transmittance and the temperature of the solution of the above and their differential curves are shown in (a) to (d), respectively. Graphs (E), (B), (G), (H) plotting the transmittance of the aqueous solution of the copolymer of R5, R2, R6, and a mixture of R5 and R6 1: 1 and the temperature of the solution. And their differential curves are shown in (e), (b), (g), and (h), respectively.

The composition of the present invention may be a composition having an upper critical solution temperature containing a copolymer of acrylamide and acrylonitrile for use as a cosmetic or an external preparation for skin, or a composition having a temperature at which the solubility rapidly increases. However, the composition is not particularly limited, and includes, in addition to the above-mentioned copolymer, a cosmetic component and a skin external preparation component. Further, as a method for lowering the upper limit critical solution temperature of the cosmetic or skin external preparation of the present invention, or the temperature at which the solubility rapidly increases, a composition having an upper limit critical solution temperature containing a copolymer of acrylamide and acrylonitrile is used. The method is not particularly limited as long as it is a method of contacting an object with a surfactant such as an anionic surfactant. In the present invention, the "composition for use as a cosmetic or an external preparation for skin" means that the composition is used for a limited purpose as a cosmetic or an external preparation for skin, and is also "a composition for use". The "composition having an upper critical solution temperature or a temperature at which the solubility increases sharply" is a temperature at which the solution containing the composition has an upper critical solution temperature under specific conditions or the solubility increases sharply. Means a composition that will have.

As the copolymer of the above acrylamide and acrylonitrile, a copolymer (poly) synthesized by polymerizing the acrylamide represented by the following formula (1) and the acrylic nitrile represented by the following formula (2) as a monomer. (acrylamide-co-acrylonitrile)) (poly (AAm-co-AN)) can be mentioned, and the form of the above-mentioned copolymer may be either a random copolymer or a block copolymer, but is a functional group. From the viewpoint of uniform dispersibility, a random copolymer represented by the following formula (3) is preferable.

As a method for synthesizing the above random copolymer (poly (AAm-co-AN)), a radical reaction in which a polymer chain is extended with a radical as a reaction center can be mentioned, and specifically, a wide molecular weight distribution can be obtained. A synthesis method by free radical polymerization that can obtain the polymer to be possessed, and a synthesis method by living radical polymerization that enables control of the molecular structure while maintaining the convenience and versatility of radical polymerization, especially the molecular weight distribution (Mw / Mn). Examples thereof include a synthesis method by RAFT polymerization capable of producing a copolymer having a smaller radical.

As the above-mentioned synthesis method by free radical polymerization, in order to copolymerize acrylamide and acrylic nitrile as a monomer, a polymerization initiator that sufficiently generates a radical at the polymerization temperature and a solvent suitable for the polymerization reaction are used. , Conventionally known methods can be mentioned. Since impurities such as unreacted monomers coexist in the reaction solution of the synthesized copolymer, by further purifying the reaction solution, [poly (AAm-) co-AN)] is preferably prepared.

The synthesis method by RAFT polymerization includes a polymerization initiator that sufficiently generates radicals at the polymerization temperature in order to copolymerize acrylamide and acrylic nitrile as monomers, a solvent suitable for the polymerization reaction, and a terminal. A conventionally known method using a reversible additive-fragmentation chain transfer (RAFT agent) for controlling the reactivity of active radicals and advancing the polymerization in a pseudo-living manner can be mentioned. can.

The monomer mass charging ratio [(AAm) :( AN)] of the copolymer acrylamide and acrylonitrile is preferably 1:99 to 99: 1, preferably 50:50 to 95: 5, and 70:30 to 90. : 10 is more preferable, and 77.5: 22.5 to 85:15 is most preferable. In addition, other monomer components can be used as long as the effect of the present invention is exhibited.

Examples of the polymerization initiator include 2,2'-azobis (isobutyronitrile) (AIBN), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2'-azobis (2,2'-azobis). 2-Amidinopropane) dihydrochloride, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate Salts, azo-based polymerization initiators such as 2,2'-azobis (N, N'-dimethyleneisobutyramidin); persulfates such as potassium persulfate and ammonium persulfate; benzoyl peroxides, t-butyl hydroperoxides, A peroxide-based polymerization initiator such as hydrogen peroxide; and the like can be mentioned.

Examples of the solvent suitable for the polymerization reaction include DMSO, water, DMF and the like.

Examples of the RAFT agent include O-ethyl-S- (1-phenylethyl) dithiocarbonate, O-ethyl-S- (2-propoxyethyl) dithiocarbonate, and O-ethyl-S- (1-cyano-1-methyl). Ethyl) Dithiocarbonates such as dithiocarbonate, cyanoethyl dithiopropionate, benzyl dithiopropionate, benzyl dithiobenzoate, dithioesters such as acetoxyethyl dithiobenzoate, S-benzyl-N, N-dimethyldithiocarbamate, benzyl- Examples thereof include dithiocarbamates such as 1-pyrrolecarbodithioate, trithiocarbonates such as dibenzyltrithiocarbonate and cyanomethyl dodecyl trithiocarbonate (CMDT).

In RAFT polymerization, the number of moles of the RAFT agent to be blended is preferably 0.0001 to 0.01, more preferably 0.0002 to 0.005, and even more preferably 0. 0003 to 0.003 can be mentioned.

As a specific preparation method of [poly (AAm-co-AN)] of the present invention by free radical polymerization, acrylonitrile is dissolved in DMSO, and a solution to which acrylamide is added is degassed to prepare a starting solution, such as AIBN. (See Non-Patent Document 1 above), in which the initiator is added and reacted at 50 to 70 ° C. for 5 to 10 hours, or each ratio of acrylonitrile and acrylamide is added to deoxidized water, and potassium persulfate and polymerization are added. An initiator such as a ferrous sulfate ammonium solution is added to potassium bisulfite and polymerized at 40 ° C. for 10 minutes in a nitrogen stream, and the polymerization reaction product is immediately dropped into methanol or water to precipitate after the reaction is stopped. After washing and drying, the obtained precipitate is dissolved in DMSO or water according to the ratio of acrylonitrile and acrylamide, and reprecipitated in methanol for purification (SEN-I GAKAISHI, Vol.32, No.1). (1976)). Further, the charged monomer composition was set to 0.25 mol AN + AAm, 0.3% / monomer K ₂ S ₂ O ₈ , 0.78% / monomer NaHSO ₃ , acetate 0.05 mL, 203 mL H ₂ O. A copolymer having an AAm / AN = 0/100 to 30/70 mol composition having a polymerization time of 1 to 3 hours and a polymerization temperature of 40 ° C., and a charged composition of 0.146 mol AN + AAm, 0.0485% / monomer K. ₂ S ₂ O ₈ , 88 mL of H ₂ O, 1.54 mL of isopropanol, a copolymer having an AAm / AN = 70/30 to 100/0 mol composition with a polymerization time of 2 hours and a polymerization temperature of 50 ° C. The composition is 0.25 mol AN + AAm, 0.14% / monomer BPO, 50 mL DMF, and the polymerization time is 1 to 4 hours and the polymerization temperature is 60 ° C. AAm / AN = 0/100 to 100/0 mol composition. Examples thereof include a method of synthesizing a copolymer and purifying it using an appropriate purification solvent such as DMF, water, methanol and ethanol (see Non-Patent Document 2 above).

As a specific preparation method of [poly (AAm-co-AN)] in the present invention by RAFT polymerization, a monomer such as acrylamide or acrylonitrile is dissolved in DMSO, and a RAFT agent such as CMDT is added to degas. As the starting solution, add an initiator such as AIBN to the starting solution, react at 60 to 80 oC for 2 to 7 hours, cool to room temperature, pour the cooled reaction solution into methanol, and precipitate the copolymer. Can be exemplified by a method of drying the mixture at 30 to 50 ° C. for about 12 to 48 hours (Polym. Chem. 2016, 7, 1979-1986, etc.).

Acrylonitrile is highly volatile and may volatilize during deaeration. Therefore, in order to obtain a copolymer having a composition ratio close to the charged amount, that is, a copolymer having a target upper limit critical solution temperature, acrylonitrile is a gas immediately before the reaction solution is heated to start the polymerization reaction. It is desirable to add using a tight syringe or the like.

The weight average molecular weight (Mw) of [poly (AAm-co-AN)] in the present invention may be 8000 to 200,000 in the case of a copolymer by free radical polymerization [poly (AAm-co-AN)]. It is possible, preferably 25,000 to 175,000, more preferably 50,000 to 150,000, even more preferably 85,000 to 120,000, and in the case of a copolymer by RAFT polymerization [poly (AAm-co-AN)], 8,000 to 200,000 can be mentioned. It is preferably 8500 to 100,000, more preferably 9000 to 90000. As a method for calculating the weight average molecular weight, a method of measuring using gel permeation chromatography (GPC), preparing a calibration curve using a standard substance, and then calculating the weight average molecular weight can be mentioned.

The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of poly (AAm-co-AN) in the present invention is preferably 1.0 to 5.0, preferably 1.1 to 4 .5 is more preferable. Further, in the case of [poly (AAm-co-AN)] by free radical polymerization, 1.5 to 3.0 can be preferably mentioned, and in the case of [poly (AAm-co-AN)] by RAFT polymerization. In this case, 1.1 to 2.0 can be preferably exemplified.

The cosmetic component or skin external preparation component constituting the composition of the present invention together with the copolymer includes components generally used for cosmetics or skin external preparations, such as alcohols, moisturizers, gelling agents, and powders. , UV absorbers, preservatives, antibacterial agents, antioxidants, pH regulators, skin-beautifying ingredients, fragrances, water and the like.

Examples of the alcohols include lower alcohols such as ethanol and isopropanol, and many alcohols such as glycerin, diglycerin, polyglycerin, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-butylene glycol, and erythritol. Examples thereof include valence alcohols, sugar alcohols such as sorbitol, maltose, xylitol, and martitol, and sterols such as cholesterol, citosterol, phytosterol, and lanosterol. Examples of the moisturizer include urea, hyaluronic acid, chondroitin sulfate, pyrrolidone carboxylate and the like.

The gelling agent is not particularly limited as long as it is an aqueous gelling agent or an oily gelling agent generally used for external skin preparations or cosmetics. For example, the aqueous gelling agent includes Arabic gum, tragacant gum, galactan, and the like. Plant-based polymers such as carob gum, guar gum, karaya gum, carrageenan, pectin, agar, quince seed (derived from malmero, etc.), starch (derived from rice, corn, potato, wheat, etc.), algae colloid, tranth gum, locust bean gum, etc. , Xanthan gum, dextran, succinoglucan, purulan and other microbial polymers, collagen, casein, albumin, gelatin and other animal polymers, carboxymethyl starch, methyl hydroxypropyl starch and other starch polymers, and methyl cellulose. , Hydroxypropylmethyl cellulose, Carboxymethyl cellulose, Hydroxymethyl cellulose, Hydroxypropyl cellulose, Sodium cellulose sulfate, Sodium carboxymethyl cellulose and other cellulose-based polymers, Sodium alginate, Alginic acid propylene glycol ester and other alginic acid-based polymers, Sodium polyacrylate, Vinyl-based polymers such as carboxyvinyl polymer, alkyl-modified carboxyvinyl polymer, polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, ethylene oxide propylene oxide copolymer, bentonite, aluminum magnesium silicate, raponite, hectrite, anhydrous Examples thereof include inorganic gelling agents such as silicic acid and thickeners, and examples of the oil-based gelling agent include metal slakes such as aluminum esterate, magnesium esterate, and zinc millistate, and N-lauroyl-L-glutamic acid. , Α, γ-di-n-butylamine and other amino acid derivatives, dextrin derivatives such as dextrinpurumic acid ester, dextrin stearate ester, dextrin 2-ethylhexanoic acid palmitic acid mixed ester, fatty acid ester, sucrose palmitate ester. , Sucrose fatty acid esters such as sucrose stearic acid ester, benzylidene derivatives of sorbitol such as monobenzylidene sorbitol and dibenzylidene sorbitol, and organic modifications such as dimethylbenzyldodecylammonium montmorillonite clay and dimethyldioctadecylammonium montmorillonite clay. Clay minerals and the like can be mentioned.

Examples of the powder include inorganic powder, organic powder, metal soap powder, colored pigment, pearl pigment, metal powder, tar pigment, natural pigment and the like, and the particle shape (spherical, needle-shaped, It does not matter the particle size (smoke-like, fine particles, pigment grade, etc.) and particle structure (porous, non-porous, etc.). These powders may be used as they are, or a composite of two or more kinds of powders may be used, or surface treatment may be performed with an oil agent, a silicone compound, a fluorine compound or the like.

Examples of the ultraviolet absorber include benzoic acid-based ultraviolet absorbers such as paraaminobenzoic acid, anthranilic acid-based ultraviolet absorbers such as methyl anthranilate, salicylic acid-based ultraviolet absorbers such as methyl salicylate, and paramethoxykei skin. Examples thereof include a silicate-based ultraviolet absorber such as octyl acid, a benzophenone-based ultraviolet absorber such as 2,4-dihydroxybenzophenone, and a urocanic acid-based ultraviolet absorber such as ethyl urocanate.

Examples of the preservatives and antibacterial agents include paraoxybenzoic acid ester, benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, phenoxyethanol, salicylic acid, phenolic acid, parachlormethacresol, hexachlorophene, benzalconium chloride, and chloride. Examples thereof include chlorhexidine, trichlorocarbanilide, photosensitizer, isopropylmethylphenol and the like. Examples of the antioxidant include tocopherol, butylhydroxyanisole, dibutylhydroxytoluene and the like.

Examples of the pH adjuster include lactic acid, lactate, citric acid, citrate, glycolic acid, succinic acid, tartrate acid, malic acid, potassium carbonate, sodium hydrogencarbonate, ammonium hydrogencarbonate and the like.

Examples of the skin-beautifying component include whitening agents such as albutin, glutathione, and yukinoshita extract, cell activators and rough skin improving agents such as royal jelly, photosensitizers, and cholesterol derivatives, nonyl acid valenylamide, and nicotinic acid benzyl ester. Nicotinic acid β-butoxyethyl ester, capsaicin, zincerone, cantalist tincture, ictamol, caffeine, tannin acid, α-borneol, tocopherol nicotinate, inositol hexanicotinate, cyclanderlate, cinnaridine, trazoline, acetylcholine, verapamil, cepharanthin , Γ-Oryzanol and other blood circulation promoters, zinc oxide, tannic acid and other skin astringent agents, and sulfur, thiantolol and other antilipolytic agents.

Since the composition for use as a cosmetic or skin external preparation of the present invention contains a copolymer of acrylamide having an upper critical solution temperature and acrylonitrile, a solution containing the composition of the present invention (composition solution). Has an upper critical solution temperature or a temperature at which the solubility rises sharply. Examples of the solvent in the solution containing such a composition include a solvent for cleaning cosmetics and skin external preparations applied to body hair such as hair, eyebrows, and eyebrows, skin, lips, and nails. Examples of the washing water include water and washing water, and examples of the washing water include washing water which is a mixed solvent in which a surfactant for lowering the upper limit critical solution temperature is added to the water. Further, other cleaning components and the like can be further included as long as the effects of the present invention are exhibited. The solution containing the composition of the present invention having the upper limit critical solution temperature or the temperature at which the solubility increases rapidly is a suspension having a light transmittance of 0% from a clear solution having a transmittance of 100%. include.

The above water is not particularly limited as long as it can be used for cleaning cosmetics and external skin preparations, and is tap water, natural water, purified water, distilled water, ion-exchanged water, pure water, and milli-Q water. Such as ultra-pure water can be exemplified.

Examples of the surfactant include anionic surfactants such as SDS and sodium deoxycholate; cationic surfactants such as CTAC and benzalkonium chloride; but anionic surfactants. Can be preferably mentioned.

The concentration of the above-mentioned surfactant is not particularly limited as long as it is a normal concentration that can be contained in a detergent or a rinsing solution, and may be more than 0 mM, 5 mM or more, 10 mM or more, 15 mM or more, 20 mM or more, 30 mM or more, 100 mM or more. It can be exemplified, for example, 1 to 20 mM can be preferably exemplified.

As a method for determining the upper limit critical solution temperature of the composition in the present invention or the temperature at which the solubility rapidly increases, for example, the composition solution in which the above composition is dissolved in water at a ratio of 1 w / v% is cooled, and then the composition solution is cooled. When the temperature of the cooling composition solution is raised at any rate of 0.3 to 2.0 ° C. per minute and the light transmittance of the composition solution is measured every 0.5 ° C., 1) obtained. A method of determining the temperature at the intersection of the linear portion where the transmittance is changing and the horizontal line representing the transmittance (100%) of the clear aqueous solution as the upper limit critical solution temperature in the obtained transmittance-temperature curve. 2) In the obtained transmittance-temperature curve, there is a method of determining the temperature at which the transmittance rapidly increases as the temperature at which the solubility increases rapidly. The rate of increase in temperature of the cooling composition solution can be appropriately determined according to the magnitude of the change in the transmittance of the solution containing each composition.

The method for measuring the light transmittance is not particularly limited as long as it is a method for measuring using light having a wavelength suitable for measuring the change in the light transmittance in the composition solution, and the wavelength may be used. The wavelength in the visible light region is preferable, and specific examples thereof include wavelengths of 650 to 700 nm, preferably 660 to 680 nm. The temperature inside the cell holder when measuring the light transmittance can be maintained by using a temperature control device such as a temperature controller.

The upper limit critical solution temperature in the composition of the present invention is not particularly limited as long as it is suitable for the usage mode and cleaning conditions of cosmetics and external skin preparations, and the upper limit critical solution temperature of the composition is 10 to 70 ° C. 20 to 60 ° C. is preferable, 30 to 50 ° C. is more preferable, and 35 to 45 ° C. is particularly preferable. Further, the upper limit critical solution temperature of the composition of the present invention constituting such cosmetics and external preparations for skin is, for example, 5 to 50 ° C., 10 to 30 ° C., 15 to higher by adding a surfactant to water. The temperature is preferably lowered by 25 ° C., 10 to 15 ° C., and 5 to 10 ° C.

Further, in the composition using [Poly (AAm-co-AN)] by RAFT polymerization, 50d is used as a differential curve of the light transmittance-temperature curve in a 1 w / v% aqueous solution when washed away with water containing no surfactant. The case where it is% T / dT or more, preferably 85d% T / dT or more can be mentioned as a preferable embodiment. Such a composition is a composition in which the change in transmittance per unit temperature is large, and the solution exhibits a change in dissolution / aggregation in a narrow temperature range of 7 ° C. or lower, preferably 5 ° C. or lower, and more preferably 3 ° C. or lower. .. In Poly (AAm-co-AN) by RAFT polymerization, the reason why the change in transmittance per unit temperature is large is considered to be that the unit ratio of each polymer chain is the same, so that the change in properties becomes large even with a slight temperature change. .. Therefore, when two or more types of RAFT polymerization [Poly (AAm-co-AN)] are mixed and used, the change in transmittance per unit temperature may be small.

The composition of the present invention can be used as a cosmetic or a skin external preparation having a high cleaning effect according to various uses and operating temperature environments. For example, when Poly (AAm-co-AN) [85:15] by free radical polymerization, which is the composition of the present invention, is used as a cosmetic, when washed with water only at 22 ° C., the aqueous solution of the above composition is used. Since the temperature of the upper limit critical solution is 28 ° C, it is difficult to wash off the cosmetics, but when washed with water at 22 ° C using a cleaning agent containing a surfactant (SDS), the upper limit critical solution As the temperature drops, Poly (AAm-co-AN) [85:15] dissolves and the cosmetics fall off very well, which is advantageous when it is difficult to supply warmed water.

Further, when a composition containing a polymer having a Mw of about 28,300, which is Poly (AAm-co-AN) [85:15] by RAFT polymerization, which is the composition of the present invention, is used as a cosmetic, it is said to be such. The composition has a high change in permeability per unit temperature in an aqueous solution, and the composition that is insoluble in water at 35 ° C near the body surface temperature is completely dissolved in hot water at 40 ° C. However, since it is possible to wash the face with only hot water, it can be used as a very excellent cosmetic product with less burden on the skin.

The composition of the present invention contains one or more types of poly (AAm-co-AN) and is used as a cosmetic or an external preparation for skin. The cosmetic in the present invention includes a cosmetic water, a cream, and the like. Basic cosmetics such as milky lotion and beauty liquid, hair cosmetics such as shampoo, rinse and treatment, makeup cosmetics such as foundation, teak, eyeliner, eye shadow, mascara, eyebrow, face powder, and sunscreen makeup. Examples of base cosmetics (including non-medicinal products) and manicure can be exemplified, and examples of external skin preparations include external medicines such as liniments, lotions, and ointments.

The blending ratio of the above poly (AAm-co-AN) to the cosmetic or skin external preparation of the present invention is not particularly limited as long as the effect of the present invention is exhibited, but is usually the whole cosmetic or skin external preparation. On the other hand, 0.01 to 80% by mass is preferable, 0.1 to 50% by mass is more preferable, 1 to 20% by mass is further preferable, and one kind or two or more kinds may be appropriately combined and blended.

Examples of the form of the cosmetic or skin external preparation comprising the composition of the present invention include a liquid, a milky liquid, a cream, a gel, and a solid.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the technical scope of the present invention is not limited to these examples.

[Example 1]
(Synthesis of [Poly (AAm-co-AN)] by free radical polymerization)
The monomer mass charging ratio [acrylamide (AAm): acrylonitrile (AN)] was 77.5: 22.5, 80:20, 82.5: 17.5, 85:15, 87.5: 12.5, respectively. Six kinds of random copolymers Poly (AAm-co-AN) having a ratio of 90:10 were synthesized by a free radical polymerization method according to the following procedure with reference to the above-mentioned Non-Patent Document 3.

Acrylamide and AIBN were dissolved in DMSO (12 mL), and dissolved oxygen was removed by blowing argon gas for 30 minutes. Acrylonitrile in a proportion corresponding to acrylamide was added using a gas tight syringe to prepare a reaction solution, and the reaction was carried out at 60 ° C. for 5.5 hours in an argon atmosphere, and then cooled to room temperature. The cooled reaction solution was poured into 250 mL of methanol, and the precipitated copolymer was collected by filtration. The obtained copolymer was further washed with 150 mL of methanol and then dried in a desiccator overnight.

For the unit ratio of AAm and AN in the copolymer, the ratio of the peak derived from the amino group of AAm (near 1659 cm ^-1 ) and the peak derived from the cyano group of AN (near 2242 cm ^-1 ) by IR measurement was used as the standard sample. Determined by comparison. As a standard sample, a sample prepared by mixing AAm homopolymer and AN homopolymer at a molar fraction of 80:20, 85: 15, 90: 10, 95: 5 was used. The IR measurement was performed using a Nicolet iS10 Fourier transform infrared spectroscope (manufactured by Thermo Fisher Scientific) and a total reflection measurement (ATR) method.

The weight average molecular weight (Mw) and number average molecular weight (Mn) of the copolymer were determined by gel permeation chromatography (GPC). A JASCO PU-2080 pump, a JASCO RI-2031 differential refractometer, a JASCO 2060 column oven (all manufactured by JASCO Corporation), and a Shodex GPC KD806-M column (manufactured by Showa Denko Corporation) were used for the measurement. The calibration curve was prepared using a Pullulan standard sample (manufactured by Showa Denko), and DMSO was used as the mobile phase.

The characteristics of the six types of Poly (AAm-co-AN) (F1 to F6) synthesized by free radical polymerization are shown in Table 1 below.

[Example 2]
[Measurement of upper critical solution temperature of copolymer-containing aqueous solution synthesized by free radical polymerization]
The above F1 to F6 copolymers were dissolved in water as a solvent, and the temperature of the 1 w / v% aqueous solution was lowered and raised in 0.5 ° C. increments to determine the solubility of each copolymer at the transmittance at 670 nm. Confirmed by measuring the change. The rate of temperature increase or decrease was set to 1 ° C./min, respectively, and the measurement was started immediately after the measurement temperature was reached. After that, the reproducibility of the temperature response was confirmed by repeating the temperature change for the same sample (1stCooling-1stHeating-2ndCooling-2ndHeating). When the measurement temperature was 15 ° C. or lower, the measurement was performed while flowing argon gas through the cell holder in order to prevent dew condensation on the cell. The light transmittance was measured using a JASCO-V650 ultraviolet-visible absorptiometer (manufactured by JASCO Corporation), and the temperature inside the cell holder was adjusted using a JASCO ETC-717 temperature controller (manufactured by JASCO Corporation). The results are shown in FIGS. 1 (a) to 1 (f) as graphs plotting the light transmittance (vertical axis) and the temperature (horizontal axis) of each solution. The upper limit critical solution temperature was set as the intersection of the straight line portion where the transmittance changes and the horizontal line representing 100% transmittance in the obtained transmittance-temperature curve.

(result)
As is clear from FIGS. 1 (a) to 1 (f), a light transmittance-temperature curve was drawn for each of the aqueous solutions containing the above F1 to F6 copolymers. In addition, although there was a difference in the upper limit critical solution temperature, the reversible dissolution / aggregation phenomenon was repeated in all the copolymer-containing aqueous solutions.

In FIG. 1, the upper limit critical solution temperature at the time of raising the temperature and the upper limit critical solution temperature at the time of lowering the temperature of the 1 w / v% aqueous solution of the above F1 to F6 copolymers were as follows.
The upper limit critical solution temperature of Poly (AAm-co-AN) [77.5: 22.5] of F1 at the time of temperature rise is 68 ° C., and the upper limit critical solution temperature at the time of temperature decrease is 66 ° C. (FIG. 1 (a)). ;
The upper limit critical solution temperature of Poly (AAm-co-AN) [80:20] of F2 at the time of temperature rise is 58 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 56 ° C. (FIG. 1 (b)).
The upper limit critical solution temperature of Poly (AAm-co-AN) [82.5: 17.5] of F3 at the time of temperature increase is 45.5 ° C., and the upper limit critical solution temperature at the time of temperature decrease is 42.5 ° C. (FIG. 1). (C));
The upper limit critical solution temperature of Poly (AAm-co-AN) [85: 15] of F4 at the time of temperature rise is 31 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 28 ° C. (FIG. 1 (d)).
The upper limit critical solution temperature of Poly (AAm-co-AN) [87.5: 12.5] of F5 at the time of raising the temperature is 19.5 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 16.5 ° C. (FIG. 1). (E));
The upper limit critical solution temperature at the time of raising the temperature of Poly (AAm-co-AN) [90:10] of F6 is 9 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 6.5 ° C. (FIG. 1 (f)).

In each of the copolymer-containing aqueous solutions in Table 1, it was confirmed that as the acrylamide monomer charging ratio increased, both the upper limit critical solution temperature at the time of temperature rise and the upper limit critical solution temperature at the time of lowering the temperature decreased.

[Example 3]
[Measurement of upper critical solution temperature of copolymer mixed solution]
As a cleaning solution model for cleaning cosmetics and external skin preparations, a copolymer mixed solution using a mixed solvent in which SDS was added to an aqueous solution was investigated. The solubility of the copolymer mixed solution in which SDS was added to a 1 w / v% aqueous solution of the F1 to F6 polymers so as to have a final concentration of 100 mM was confirmed in the same manner as in Example 2. The results are shown in FIG.

(result)
As is clear from FIG. 2, in the copolymer-containing mixed solution of F1 to F6, when the monomer charging ratios are [77.5: 22.5] and [80:20], the mixed solution transmits light. A rate-temperature curve was drawn, and although there was a difference in the upper limit critical solution temperature, the reversible dissolution / aggregation phenomenon was repeated.

More specifically, the upper limit critical solution temperature of the F1 Poly (AAm-co-AN) [77.5: 22.5] + SDS100 mM mixed solution at the time of temperature rise is 70 ° C. or higher, and the upper limit critical solution temperature at the time of lowering the temperature is At 69 ° C., there was no significant difference in the upper limit critical solution temperature compared to before the addition of SDS (FIG. 2 (a)). The upper limit critical solution temperature of the F2 Poly (AAm-co-AN) [80:20] + SDS100 mM mixed solution at the time of temperature rise is 53 ° C., the upper limit critical solution temperature at the time of lowering the temperature is 47 ° C., and the light transmittance-temperature. The slope of the curve became gentle, and the upper limit critical solution temperature at the time of temperature rise and temperature decrease became low (Fig. 2 (b)). F3 Poly (AAm-co-AN) [82.5: 17.5] + SDS100 mM mixed solution (FIG. 2 (c)), F4 [Poly (AAm-co-AN)] [85:15] + SDS100 mM Mixed solution (FIG. 2 (d)), F5 Poly (AAm-co-AN) [87.5: 12.5] + SDS100 mM mixed solution (FIG. 2 (e)), F6 Poly (AAm-co-). AN) [90:10] + SDS 100 mM mixed solution (FIG. 2 (f)) did not draw a light transmittance-temperature curve, and the mixed solution remained dissolved without showing agglomeration.

[Example 4]
Further studies were continued on the F3 Poly (AAm-co-AN) [82.5: 17.5].

SDS is added to a 1 w / v% aqueous solution of Poly (AAm-co-AN) [82.5: 17.5] of F3 so that the final concentrations are 5 mM, 10 mM, 15 mM, 20 mM, 30 mM, and 100 mM, respectively. The solubility of each mixed solution was confirmed in the same manner as in Example 2. The results are shown in FIGS. 3 (a) to 3 (f).

(result)
The upper limit critical solution at the time of temperature rise of the mixed solution in which SDS was added so that the final concentration was 5 mM to the 1 w / v% aqueous solution of Poly (AAm-co-AN) [82.5: 17.5] of F3. The temperature is 44.5 ° C., the upper limit critical solution temperature at the time of lowering is 41 ° C (Fig. 3 (a)), and the upper limit critical solution temperature at the time of raising the temperature of the mixed solution to which SDS is added so that the final concentration is 10 mM. Is 36 ° C., the upper limit critical solution temperature at the time of temperature decrease is 29.5 ° C., and the upper limit critical solution temperature at the time of temperature increase and temperature decrease is about 15 ° C. lower than that when SDS is not added to the aqueous solution. (Fig. 3 (b)).
The upper limit critical solution temperature at the time of temperature rise is 27 ° C, the upper limit critical solution temperature at the time of temperature decrease is 17 ° C, and the upper limit at the time of temperature rise and temperature decrease of the mixed solution to which SDS is added so that the final concentration is 15 mM. The critical solution temperature was lower at around 20 ° C. than when SDS was not added to the aqueous solution (FIG. 3 (c)).
The upper limit critical solution temperature at the time of lowering the temperature of the mixed solution to which SDS was added so that the final concentration was 20 mM was 9.5 ° C. The light transmittance-temperature curve at the time of temperature rise was not drawn (FIG. 3 (d)).
In the mixed solution to which SDS was added so that the final concentration was 30 mM and 100 mM, the light transmittance-temperature curve was not drawn, and the mixed solution remained dissolved without showing cohesiveness (FIG. 3 (e)). And (f)).

[Example 5]
As the surfactant, CTAC (final concentration 100 mM), which is a cationic surfactant, was used instead of SDS (final concentration 100 mM), and the same study as in Example 3 was conducted. The results are shown in FIGS. 4A to 4F.

(result)
As is clear from FIG. 4, for the CTAC mixed solution of the above F1 to F6 copolymers, the monomer charging ratio is F1 [77.5: 22.5] and F2 [80:20] excluding F6 [90:10]. ], F3 [82.5: 17.5], F4 [85:15] and F5 [87.5: 12.5], a light transmittance-temperature curve was drawn. Further, although there was a difference in the upper limit critical solution temperature in the five copolymer-containing mixed solutions, the reversible dissolution / aggregation phenomenon was repeated.

The upper limit critical solution temperature at the time of raising the temperature and the upper limit critical solution temperature at the time of lowering the temperature of the CTAC (final concentration 100 mM) mixed solution containing the above F1 to F6 copolymers were as follows.
The upper limit critical solution temperature at the time of raising the temperature of the CTAC mixed solution of F1 is 66 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 62.5 ° C. (FIG. 4A);
The upper limit critical solution temperature at the time of raising the temperature of the CTAC mixed solution of F2 is 54 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 50 ° C. (FIG. 4 (b)).
The upper limit critical solution temperature at the time of raising the temperature of the CTAC mixed solution of F3 is 42 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 38 ° C. (FIG. 4 (c)).
The upper limit critical solution temperature at the time of raising the temperature of the CTAC mixed solution of F4 is 27.5 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 23.5 ° C. (FIG. 4 (d)).
The upper limit critical solution temperature at the time of raising the temperature of the CTAC mixed solution of F5 is 17.5 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 13 ° C. (FIG. 4 (e)).
The CTAC mixed solution of F6 did not show cohesiveness (FIG. 4 (f)). In any of the CTAC mixed solutions of F1 to F5 excluding the CTAC mixed solution of F6, the upper limit critical solution temperature was shifted to the low temperature side. However, the lowering effect was weaker than that of SDS.

[Comparison example]
Sodium chloride (final concentration 100 mM) was used instead of SDS (final concentration 100 mM), and the same study as in Example 3 was conducted. The results are shown in FIGS. 5 (a) to 5 (f).

(result)
As is clear from FIGS. 5 (a) to 5 (f), when sodium chloride is added to the aqueous solutions of these six F1 to F6 copolymers, the change in the upper limit critical solution temperature is almost observed in all the copolymer solutions. I couldn't.

[Example 6]
(Synthesis of [Poly (AAm-co-AN)] by RAFT polymerization)
Poly (AAm-co-AN), 6 types of random copolymers in which the monomer mass charging ratio [acrylamide (AAm): acrylonitrile (AN)] is in the range of 80:20 to 85:15 and the content of CMDT is different. ) (R1 to R6 in Table 2) were synthesized by the RAFT polymerization method according to the following procedure with reference to Polymer. Chem. 2016, 7, 1979-1986.

Acrylamide and AIBN were dissolved in DMSO (6 mL), CMDT was added to further dissolve the mixture, and then the dissolved oxygen was removed by blowing argon gas for 30 minutes. Acrylonitrile in a proportion corresponding to acrylamide was added using a gas tight syringe to prepare a reaction solution, which was reacted at 70 oC for 3.5 hours in an argon atmosphere and then cooled to room temperature.
The cooled reaction solution was poured into 150 mL of methanol, and the precipitated copolymer was collected by filtration. The obtained copolymer was further washed with 150 mL of methanol and then dried in a desiccator overnight.

The unit ratio of AAm and AN in the copolymer, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the copolymer are determined by the above-mentioned [Synthesis of Poly (AAm-co-AN) copolymer by free radical polymerization. ], The measurement was performed using the method described in.

The characteristics of the six types of [Poly (AAm-co-AN)] (R1 to R6) synthesized by RAFT polymerization are shown in Table 2 below.

[Example 7]
[Measurement of Upper Critical Solution Temperature of Copolymer-Containing Aqueous Solution Synthesized by RAFT Polymerization 1]
The above R1 copolymer is dissolved in water as a solvent, and the temperature of the 1 w / v% aqueous solution or the 0.1 w / v% aqueous solution is lowered and raised in 0.5 ° C. increments to improve the solubility of each copolymer. confirmed. Since the copolymer synthesized by RAFT polymerization has a large change in transmittance per unit temperature, the rate of temperature rise or fall was set to 0.5 ° C./min, respectively, and the [By free radical polymerization] of Example 2 was used. Measurement of the upper limit critical solution temperature of the synthesized copolymer-containing aqueous solution] was used for the measurement. The results are shown in FIGS. 6 (A) and 6 (A1) as graphs plotting the light transmittance (vertical axis) and the temperature (horizontal axis) of each solution. Further, the differential curves of the graph of the copolymer-containing aqueous solution of R1 are shown in FIGS. 6A and 6A, respectively. For comparison, the same study results for the 1 w / v% aqueous solution and the 0.1 w / v% aqueous solution of the F3 copolymer synthesized by free radical polymerization are shown in FIGS. 6 (F) and 6 (F1). The differential curves are shown in FIGS. 6 (f) and 6 (f1).

(result)
As is clear from FIG. 6, the upper limit critical solution temperature at the time of raising the temperature of the 1 w / v% aqueous solution of [Poly (AAm-co-AN)] [82.5: 17.5] of R1 is 30 ° C., and the upper limit at the time of lowering the temperature. The critical solution temperature is 27.5 ° C. (FIG. 6 (A)), the upper limit critical solution temperature at the time of raising the temperature of the 0.1 w / v% aqueous solution is 28 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 25.5 ° C. (FIG. 6 (A1)). On the other hand, the upper limit critical solution temperature at the time of raising the temperature of the 1w / v% aqueous solution of [Poly (AAm-co-AN)] [82.5: 17.5] of F3 is 45.5 ° C., and the upper limit criticality at the time of lowering the temperature. The solution temperature is 42.5 ° C. (FIG. 6 (F)), the upper limit critical solution temperature at the time of raising the temperature of the 0.1 w / v% aqueous solution is 39.5 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 37 ° C. ( FIG. 6 (F1)).

Further, the aqueous solution of [Poly (AAm-co-AN)] synthesized by RAFT polymerization is a 1 w / v% aqueous solution (FIG. 6 (a)) and a 0.1 w / v% aqueous solution (FIG. 6 (a1)). The maximum value of the change in transmittance per unit temperature of the upper limit critical solution temperature at that time is 190 d% T / dT and 90 d% T / dT, respectively, and of [Poly (AAm-co-AN)] synthesized by free radical polymerization. The unit temperature is compared with the respective values of 27 d% T / dT and 6 d% T / dT in the 1 w / v% aqueous solution (FIG. 6 (f)) and the 0.1 w / v% aqueous solution (FIG. 6 (f1)). The change in transmittance per hit was remarkably large.

[Example 8]
[Measurement of Upper Critical Solution Temperature of Copolymer-Containing Aqueous Solution Synthesized by RAFT Polymerization 2]
Among the above-mentioned 6 kinds of synthesized copolymers Poly (AAm-co-AN), the above-mentioned R1 to R4 copolymers having a unit ratio of [82.5: 17.5] and different Mw. The temperature of the 1 w / v% aqueous solution was lowered and raised in 0.5 ° C. increments, and the solubility of each copolymer was confirmed by measuring the change in transmittance at 670 nm. The method described in Example 2 [Measurement of Upper Limit Critical Solution Temperature of Copolymer-Containing Aqueous Solution Synthesized by Free Radical Polymerization] except that the rate of temperature increase or decrease was set to 0.5 ° C./min. The measurement was performed at. The results are shown in FIGS. 7A to 7D as graphs plotting the light transmittance (vertical axis) and the temperature (horizontal axis) of each solution. Further, the differential curves thereof are shown in FIGS. 7 (a) to 7 (d), respectively.

(result)
As is clear from FIGS. 7A to 7D, a light transmittance-temperature curve was drawn for each of the aqueous solutions of the above-mentioned R1 to R4 copolymers. Moreover, although there was a difference in the upper limit critical solution temperature, the reversible dissolution / aggregation phenomenon was repeated in all the copolymer-containing solutions.

In FIG. 7, the upper limit critical solution temperature at the time of raising the temperature and the upper limit critical solution temperature at the time of lowering the temperature of the 1 w / v% aqueous solution of the copolymers of R1 to R4 were as follows.
The upper limit critical solution temperature of Poly (AAm-co-AN) [82.5: 17.5] (Mw: 9970) of R1 at the time of raising the temperature is 30 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 27.5 ° C. (Fig. 7 (A));
The upper limit critical solution temperature of Poly (AAm-co-AN) [82.5: 17.5] (Mw: 26400) of R2 at the time of temperature rise is 30 ° C., and the upper limit critical solution temperature at the time of temperature decrease is 28.5 ° C. (Fig. 7 (B));
The upper limit critical solution temperature at the time of raising the temperature of Poly (AAm-co-AN) [82.5: 17.5] (Mw: 38700) of R3 is 32.5 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 29. 5 ° C (Fig. 7 (C));
The upper limit critical solution temperature of Poly (AAm-co-AN) [82.5: 17.5] (Mw: 74800) of the above R4 at the time of temperature rise is 30 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 29 ° C. (Fig.). 7 (D));

As is clear from the results of FIGS. 7A to 7D, in each aqueous solution containing [Poly (AAm-co-AN)] by four types of RAFT polymerization having the same unit ratio but different Mw. , The upper limit critical solution temperature at the time of temperature rise and the temperature decrease was not so different. However, as is clear from FIGS. 7 (a) to 7 (d), when the change in transmittance per unit temperature is examined, the change in transmittance is larger than that of the aqueous solution of F3 in FIG. It was confirmed that the sensitivity of the temperature response in the aqueous solution was high. Specifically, in R1, the maximum value of d% T / dT at the time of temperature decrease was 190, in R2 it was 105, in R3 it was 100, and in R4 it was 115. Further, the smaller the molecular weight, the larger the degree of change in transmittance tended to be, and among them, the change in transmittance was remarkably large in R1 having the smallest molecular weight.

[Example 9]
[Measurement of Upper Critical Solution Temperature of Copolymer-Containing Aqueous Solution Synthesized by RAFT Polymerization 3]
For the above-mentioned mixture of R5, R2, R6 and R5 and R6 of 1: 1, the temperature was lowered and raised in 0.5 ° C. increments for a 1 w / v% aqueous solution in which water was dissolved as a solvent, and each copolymer was subjected to temperature reduction and temperature rise. Solubility was confirmed. The method described in Example 2 [Measurement of Upper Limit Critical Solution Temperature of Copolymer-Containing Aqueous Solution Synthesized by Free Radical Polymerization] except that the rate of temperature increase or decrease was set to 0.5 ° C./min. The measurement was performed at. The results are shown as a graph in which the light transmittance (vertical axis) and the temperature (horizontal axis) of each solution are plotted. Plots are shown in FIGS. 8 (E), (B), (G), and (H). The differential curves thereof are shown in plots 8 (e), (b), (g), and (h), respectively.

(result)
As is clear from FIGS. 8 (E), (B), (G), and (H), all of the above-mentioned aqueous solutions of the copolymer of R5, R2, R6, and a mixture of R5 and R6 in a ratio of 1: 1 are used. A light transmittance-temperature curve was drawn. Moreover, although there was a difference in the upper limit critical solution temperature, the reversible dissolution / aggregation phenomenon was repeated in all the copolymer-containing solutions.

In FIG. 8, the upper limit critical solution temperature at the time of raising the temperature and the upper limit critical solution temperature at the time of lowering the temperature of the 1 w / v% aqueous solution of the copolymer of the above R5, R2, R6, and the mixture of R5 and R6 are 1: 1. It was as follows.
The upper limit critical solution temperature of Poly (AAm-co-AN) [85:15] of R5 at the time of temperature rise is 12.5 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 10.5 ° C. (FIG. 8 (E)). ;
The upper limit critical solution temperature of Poly (AAm-co-AN) [82.5: 17.5] of R2 at the time of temperature rise is 30 ° C., and the upper limit critical solution temperature at the time of temperature decrease is 28.5 ° C. (FIG. 8 (B). ));
The upper limit critical solution temperature of Poly (AAm-co-AN) [85:15] of R6 at the time of temperature rise is 37 ° C., and the upper limit critical solution temperature at the time of lowering the temperature is 36 ° C. (FIG. 8 (G)).
The upper limit critical solution temperature of the mixture of R5 and R6 of 1: 1 when the temperature was raised was 37.5 ° C, and the upper limit critical solution temperature when the temperature was lowered was 34 ° C (FIG. 8 (H)).

From the results of FIG. 8, in each aqueous solution containing one kind of [Poly (AAm-co-AN)] synthesized by RAFT polymerization such as (E), (B), (G), the upper limit at the time of temperature rise and the temperature decrease. It was confirmed that the critical solution temperature had a larger change in transmittance than the aqueous solution of F3 in FIG. 6, and the sensitivity of the temperature response in the aqueous solution of the copolymer was high. On the other hand, the change in transmittance per unit temperature of the aqueous solution containing two types of [Poly (AAm-co-AN)] synthesized by RAFT polymerization of (H) became very small, and the sensitivity of the temperature response decreased. From this, the increase in the transmittance change of [Poly (AAm-co-AN)] synthesized by RAFT polymerization means that the unit ratio of each polymer chain is the same in the copolymer synthesized by RAFT polymerization. It is thought that this is due to.

[Example 10]
Mascara was prepared by the following formulation and manufacturing method.
(Component) (% by mass)
(1) Hydrogenated polyisobutene remaining amount (2) Dextrin palmitate 2.0
(3) Beeswax 9.0
(4) Carnauba wax 5.0
(5) Polymethylsilsesquioxane 5.0
(6) Disteardimonium hectorite 1.0
(7) Talc 5.0
(8) Black iron oxide 5.0
(9) Silicic anhydride 1.0
(10) Purified water 10.0
(11) F3 of Example 1; poly (AAm-co-AN) [85:15] 1.0

(Production method)
A. The components (1) to (5) are heated and dissolved at 100 ° C. and cooled to 70 ° C.
B. Ingredients (6) to (9) are added to A and mixed uniformly.
C. After the components (10) to (11) were uniformly mixed and dissolved at 70 ° C., they were added to B and emulsified at 70 ° C. and cooled to room temperature to obtain mascara.

The mascara obtained as described above was not removed by water or sweat, but could be easily removed by using hot water and soap at 42 ° C. The soap contains sodium fatty acid as a surfactant component.

[Example 11]
An ointment was prepared according to the following formulation and manufacturing method.
(Component) (% by mass)
(1) Stearyl alcohol 18.0
(2) Japan wax 15.0
(3) Polyoxyethylene (20 mol) monooleic acid ester 0.3
(4) Tocopherol 0.1
(5) Vaseline 30.0
(6) Glycerin 10.0
(7) Remaining amount of purified water (8) R6 of Example 6; poly (AAm-co-AN) [80:20] 3.0

(Production method)
A: Ingredients (1) to (5) are uniformly mixed at 70 ° C.
B: After the components (7) and (8) are uniformly mixed and dissolved at 70 ° C., the component (6) is added and uniformly mixed.
C: B was added to A, emulsified at 70 ° C., and cooled to room temperature to obtain an ointment.

The ointment obtained as described above was not removed by water or sweat, but could be easily removed by using hot water at 42 ° C.

The present invention is very useful in the fields of cosmetics and external skin preparations.

Claims (9)

A composition having an upper critical solution temperature containing a copolymer of acrylamide and acrylonitrile or a temperature at which the solubility rapidly increases for use as a cosmetic or an external preparation for skin. The composition according to claim 1, wherein the copolymer has a monomer mass charging ratio of acrylamide: acrylonitrile of 77.5: 22.5 to 85:15. The composition according to claim 1 or 2, wherein the copolymer has a weight average molecular weight of 8,000 to 200,000. The composition according to any one of claims 1 to 3, wherein the copolymer is a random copolymer. The composition according to claim 4, wherein the random copolymer is a random copolymer synthesized by free radical polymerization. The composition according to claim 4, wherein the random copolymer is a random copolymer synthesized by RAFT polymerization. The composition according to any one of claims 1 to 6, wherein the composition has temperature sensitivity when 1 to 20 mM of sodium dodecyl sulfate is added. The composition according to claim 6 or 7, wherein the maximum value of the differential curve of the light transmittance-temperature curve in a 1 w / v% aqueous solution containing no surfactant is 50 d% T / dT or more. An upper limit characterized by contacting a surfactant with a cosmetic or skin external preparation comprising a composition having an upper limit critical solution temperature containing a copolymer of acrylamide and acrylonitrile or a temperature at which the solubility rapidly increases. A method of lowering the critical solution temperature or the temperature at which the solubility rises rapidly.

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