JP7498049B2 - Method for producing post-foamable composition - Google Patents

Description

The present invention relates to a method for producing a post-foamable composition. More specifically, the present invention relates to a method for producing a post-foamable composition that contains a hydrofluoroolefin having a boiling point of 5 to 25°C as a foaming agent, but can be discharged in a gel form while suppressing foaming of the foaming agent during discharge, and can be foamed by applying shear with a finger or the like to the discharged gel.

Patent Document 1 discloses a method for producing an aerosol product in which an aqueous concentrate for aerosols and a low-boiling-point solution are fed into a mixing means using a constant-volume pressure delivery means, mixed, and the mixture is filled into a container. In particular, Patent Document 1 discloses that the aqueous concentrate and the low-boiling-point solvent are heated or cooled to a temperature below the boiling point by heat exchange before being fed to the constant-volume pressure delivery means.

Japanese Patent Application Laid-Open No. 2-251261

In the invention described in Patent Document 1, isopentane is used as the low boiling point solution. Isopentane is flammable. Therefore, in order to suppress flammability, it is conceivable to replace the low boiling point solution with a hydrofluoroolefin, which is less flammable. However, hydrofluoroolefin has a lower boiling point than isopentane. Therefore, aerosol products containing hydrofluoroolefin are prone to vaporization when discharged. As a result, the discharged material is prone to foaming when discharged, making it difficult to discharge in a gel form.

The present invention has been made in consideration of such conventional problems, and aims to provide a method for producing a post-foamable composition that can be discharged in a gel form while suppressing foaming of the foaming agent even when it contains a hydrofluoroolefin with a boiling point of 5 to 25°C as a foaming agent, and that can be foamed by applying shear with a finger or the like to the discharged gel.

The present invention, which solves the above problems, mainly includes the following configurations:

(1) A method for producing a post-foamable composition comprising an aqueous stock solution containing water and a surfactant, and a foaming agent containing a hydrofluoroolefin having a boiling point of 5 to 25°C, the method comprising a degassing step for reducing the amount of air dissolved in the foaming agent to the saturated solubility amount at 25°C or less, an emulsification step for mixing the degassed foaming agent with the aqueous stock solution to emulsify, and a filling step for filling the obtained emulsion into a discharge container.

According to this configuration, the compressed gas (air) dissolved in the hydrofluoroolefin having a boiling point of 5 to 25°C is degassed by the degassing process. As a result, foaming originating from the dissolved air is easily suppressed in the discharged post-foamable composition. Therefore, the post-foamable composition can be discharged in a gel state. The post-foamable composition discharged in a gel state can be easily foamed by applying shear with a finger or the like.

(2) The method for producing a post-foamable composition according to (1), wherein the degassing step includes a heating step of heating the foaming agent to a temperature equal to or higher than the boiling point.

With this configuration, the method for producing the post-foamable composition makes it easy to adjust the amount of air dissolved in the foaming agent.

(3) The method for producing a post-foamable composition according to (2), wherein the emulsification step is a step of heating the aqueous concentrate to a temperature equal to or higher than the boiling point of the foaming agent, and mixing the heated aqueous concentrate with the heated foaming agent.

With this configuration, the viscosity of the mixture of the aqueous concentrate and the foaming agent increases slowly during the emulsification process. Therefore, the aqueous concentrate and the foaming agent are easily mixed uniformly. As a result, the resulting post-foamable composition is easily discharged stably.

(4) The method for producing a post-foamable composition according to (2) or (3), wherein the heating step includes a discharging step of discharging gas from the container or piping that contains the foaming agent to the outside.

With this configuration, the air dissolved in the foaming agent can be discharged to the outside during the discharging process. This makes it possible to prevent the air from redissolving in the foaming agent. As a result, the resulting post-foamable composition is more likely to suppress foaming during discharge and is more likely to be discharged in a gel-like form.

(5) The method for producing a post-foamable composition according to any one of (1) to (4), wherein the emulsification step is a step of emulsifying the aqueous concentrate and the foaming agent at 30 to 80°C.

With this configuration, the viscosity of the mixture of the aqueous concentrate and the foaming agent is less likely to increase during the emulsification process. This makes it easier to maintain the temperature of the mixture and to fill it into the discharge container. The viscosity of the filled mixture (post-foamable composition) is then likely to increase.

According to the present invention, even if a hydrofluoroolefin having a boiling point of 5 to 25°C is used as a foaming agent, the foaming of the foaming agent can be suppressed during extrusion, and the composition can be extruded in a gel form, and the extruded gel can be foamed by applying shear with a finger or the like. This provides a method for producing a post-foamable composition.

<Post-foamable composition and method for producing post-foamable composition>
The method for producing a post-foamable composition according to one embodiment of the present invention is a method for producing a post-foamable composition comprising an aqueous concentrate containing water and a surfactant, and a foaming agent containing a hydrofluoroolefin having a boiling point of 5 to 25° C. The method for producing a post-foamable composition includes a degassing step for reducing the amount of air dissolved in the foaming agent to a saturated solubility amount or less at 25° C., an emulsification step for mixing the degassed foaming agent and the aqueous concentrate to emulsify, and a filling step for filling a discharge container with the obtained emulsion. Each step will be described below. In the following description, the post-foamable composition, which is the target product, will be described first for clarity.

The post-foamable composition of this embodiment contains an aqueous concentrate containing water and a surfactant, and a foaming agent containing a hydrofluoroolefin having a boiling point of 5 to 25°C.

(Aqueous stock solution)
The aqueous concentrate contains water and a surfactant.

Water: Water is used as the main solvent of the aqueous concentrate. By including water, the aqueous concentrate is emulsified with a foaming agent containing a hydrofluoroolefin having a boiling point of 5 to 25°C to form a stable post-foamable composition. The post-foamable composition becomes a gel-like substance when discharged, and the gel-like substance gradually foams thereafter, or foams when sheared with a finger or the like to form a foam, which is easy to apply and spread on application sites such as the face, hair, arms, hands, and legs.

The water is not particularly limited. Examples of the water include purified water, ion-exchanged water, saline solution, deep sea water, etc.

The water content is not particularly limited. For example, the water content in the post-foamable composition is preferably 30% by mass or more, more preferably 40% by mass or more. The water content in the post-foamable composition is preferably 90% by mass or less, more preferably 80% by mass or less. When the water content is within the above range, the aqueous concentrate is emulsified with the foaming agent containing hydrofluoroolefin to form a stable post-foamable composition, which becomes gel-like when discharged and then easily foams to form a foam.

Surfactant The surfactant is blended to emulsify the aqueous concentrate and the hydrofluoroolefin to form a stable post-foamable composition. The surfactant is also blended for the purposes of stably holding the hydrofluoroolefin in a gel state during discharge and foaming the aqueous concentrate by vaporizing the hydrofluoroolefin to form a foam, etc.

The surfactant is not particularly limited. Examples of the surfactant include anionic surfactants such as fatty acid soap, alkyl sulfate, polyoxyethylene alkyl ether sulfate, alkyl phosphate, and polyoxyethylene alkyl ether phosphate; polyoxyethylene alkyl ether, polyglycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene polyoxypropylene alkyl ether, polyethylene glycol fatty acid ester, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkyl ether fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and polyoxyethylene sorbitan fatty acid ester. nonionic surfactants such as fatty acid esters; associative thickeners such as (acrylic acid/steareth itaconate) copolymer, (acrylic acid/ceteth itaconate) copolymer, and acrylic acid/aminoacrylate/C10-30 alkyl PEG-20 itaconate copolymer; cationic surfactants such as alkyl ammonium salts and polyoxyethylene alkylamines; amphoteric surfactants such as alkyl betaines and fatty acid amidopropyl betaines; silicone surfactants; amino acid surfactants such as N-acyl glutamate, N-acyl glutamic acid, N-acyl glycine salts, and N-acylalanine salts. Surfactants may be used in combination.

Among these, the surfactant is preferably a fatty acid soap or a polyoxyethylene alkyl ether, from the viewpoints that the viscosity slowly increases in the emulsification process in which the aqueous concentrate and the hydrofluoroolefin are emulsified, making it easier to form a uniform composition, making it easier to fill the post-foamable composition into a discharge container, and the viscosity increases after filling into the discharge container to form a stable post-foamable composition that is easy to discharge in a gel-like form, and fatty acid soap is more preferable. The fatty acid soap is preferably a saponification product of a fatty acid containing lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, etc. and an alkali, and more preferably a saponification product of myristic acid, palmitic acid, and an organic amine such as triethanolamine or diisopropanolamine, or an inorganic alkali such as sodium hydroxide or potassium hydroxide. In addition, it is preferable to use a polyoxyethylene alkyl ether having an HLB value of 10 or more, from the viewpoints that the post-foamable composition has excellent foamability and is easy to form fine bubbles, and that it contains a solid oil described later, suppresses foaming immediately after discharge, and prevents precipitation of the solid oil when it is easy to discharge in a gel-like form.

The surfactant content is not particularly limited. For example, the surfactant content in the post-foamable composition is preferably 3% by mass or more, and more preferably 5% by mass or more. The surfactant content in the post-foamable composition is preferably 30% by mass or less, and more preferably 25% by mass or less. When the surfactant content is within the above range, the viscosity of the emulsion increases slowly in the emulsification process, making it easier to form a uniform composition, and easier to fill the discharge container.

Optional Components In addition to the water and surfactant described above, the post-foamable composition may contain optional components such as active ingredients, oils, alcohols, monosaccharides, water-soluble polymers, powders, etc., as appropriate.

The active ingredient can be appropriately selected depending on the application and purpose of the product. For example, the active ingredient may be various fragrances such as natural fragrances and synthetic fragrances; styling agents such as amphoteric resins such as dialkylaminoalkyl (meth)acrylate-(meth)acrylic acid alkyl ester copolymers, alkyl acrylate amide-hydroxyalkyl acrylate-alkylaminoalkyl methacrylate copolymers, and emulsion resins such as alkyl acrylate copolymer emulsions, alkyl acrylate-styrene copolymer emulsions, vinylpyrrolidone-styrene copolymer emulsions, and acrylic acid-hydroxyester acrylic acid copolymer emulsions; cooling agents such as l-menthol, camphor, and peppermint oil; retinol, retinol acetate, retinol palmitate, pantothenic acid, and the like. vitamins such as calcium ascorbate, magnesium ascorbyl phosphate, sodium ascorbate, dl-α-tocopherol, tocopherol acetate, tocopherol, tocopherol nicotinate, dibenzoylthiamine, riboflavin and mixtures thereof; antioxidants such as ascorbic acid, α-tocopherol, dibutylhydroxytoluene, butylhydroxyanisole; amino acids such as glycine, alanine, leucine, serine, tryptophan, cysteine, methionine, aspartic acid, glutamic acid, arginine; moisturizers such as collagen, hyaluronic acid, caronic acid, sodium lactate, dl-pyrrolidone carboxylate, keratin, casein, lecithin, urea, etc.; paraoxybenzoic acid esters, Preservatives such as sodium benzoate, potassium sorbate, and phenoxyethanol; bactericidal disinfectants such as benzalkonium chloride, benzethonium chloride, chlorhexidine chloride, and parachlormetacresol; extracts such as royal jelly extract, peony extract, loofah extract, rose extract, lemon extract, aloe extract, calamus root extract, eucalyptus extract, sage extract, tea extract, seaweed extract, placenta extract, and silk extract; astringents such as zinc oxide, allantoin hydroxyaluminum, tannic acid, citric acid, and lactic acid; anti-inflammatory agents such as allantoin, glycyrrhetinic acid, dipotassium glycyrrhizinate, and azulene; methacrylate laurate, methyl benzoate, methyl phenylacetate, and geranyl clotreol. deodorants such as hexyl benzoate, acetophenone myristate, benzyl acetate, benzyl propionate, and green tea extract; ultraviolet absorbers such as diethylaminohydroxybenzoylhexyl benzoate, 2-ethylhexyl paramethoxycinnamate, ethylhexyl triazone, oxybenzone, hydroxybenzophenone sulfonic acid, dihydroxybenzophenone sodium sulfonate, and dihydroxybenzophenone; ultraviolet scattering agents such as zinc oxide, titanium oxide, and octyltrimethoxysilane-coated titanium oxide; whitening agents such as arbutin and kojic acid; antiperspirants such as chlorohydroxyaluminum and isopropylmethylphenol; and anti-inflammatory analgesics such as methyl salicylate, indomethacin, felbinac, and ketoprofen.

When an active ingredient is blended, the content of the active ingredient is not particularly limited. For example, the content of the active ingredient in the post-foamable composition is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more. The content of the active ingredient in the post-foamable composition is preferably 20% by mass or less, and more preferably 15% by mass or less. By having the content of the active ingredient within the above range, the effect of blending the active ingredient is easily obtained, and the foamability of the post-foamable composition is less likely to be reduced by the active ingredient.

Oil agents are blended in the process of emulsifying the aqueous concentrate and the hydrofluoroolefin for the purposes of slowly increasing the viscosity to facilitate the formation of a uniform composition, making it easier to fill the emulsion, etc. In addition, oil agents are blended in for the purposes of suppressing the evaporation of the hydrofluoroolefin during discharge to facilitate discharging it in a gel state, etc.

The oil is not particularly limited. Examples of the oil include ester oil, hydrocarbon oil, oils and fats, silicone oil, liquid higher fatty acids, liquid higher alcohols, solid hydrocarbons, solid higher fatty acids, solid higher alcohols, and alkyl glucosides. These may be used in combination.

In addition, in order to make it easier to form a uniform composition by slowly increasing the viscosity during the emulsification process and to make it easier to fill the emulsion, and also to suppress the evaporation of the hydrofluoroolefin during discharge and make it easier to discharge in a gel state, it is preferable to add a liquid oil that is liquid at 25°C, such as ester oil, hydrocarbon oil, oils and fats, silicone oil, liquid higher fatty acids, and liquid higher alcohols.

The ester oil is not particularly limited. Examples of the ester oil include methyl pentanediol dineopentanoate, diethyl pentanediol dineopentanoate, diethyl sebacate, diisopropyl adipate, diethylhexyl naphthalene dicarboxylate, dibutyl octyl sebacate, neopentyl glycol di-2-ethylhexanoate, neopentyl glycol dicaprate, propylene glycol dilaurate, ethylene glycol distearate, diethylene glycol dilaurate, diethylene glycol distearate, diethylene glycol diisostearate, diethylene glycol dioleate, triethylene glycol dilaurate, distearate, Examples of suitable oleic acid salts include triethylene glycol phosphate, triethylene glycol diisostearate, triethylene glycol dioleate, propylene glycol monostearate, propylene glycol monooleate, ethylene glycol monostearate, glyceryl tri-2-ethylhexanoate, tri(caprylic/capric acid)glycerin, isononyl isononanoate, isotridecyl isononanoate, diethoxyethyl succinate, diisostearyl malate, isopropyl myristate, isopropyl palmitate, ethyl linoleate, cetyl isooctanoate, octyl hydroxystearate, and ethylhexyl hydroxystearate. Among these, the ester oil is preferably an ester of a straight-chain fatty acid and a lower alcohol, such as isopropyl myristate, isopropyl palmitate, or ethyl linoleate, or a polybasic acid ester, such as methyl pentanediol dineopentanoate, diethyl pentanediol dineopentanoate, diethyl sebacate, diisopropyl adipate, diethylhexyl naphthalene dicarboxylate, or dibutyl octyl sebacate, because it is easy to emulsify the aqueous concentrate and the hydrofluoroolefin to form a homogeneous phase.

The hydrocarbon oil is not particularly limited. Examples of the hydrocarbon oil include liquid paraffin, kerosene, squalene, squalane, and isoparaffin. Among these, the hydrocarbon oil is preferably liquid paraffin, etc., because it is easy to emulsify the aqueous concentrate and the hydrofluoroolefin to form a uniform composition.

The oils and fats are not particularly limited. Examples of the oils and fats include avocado oil, camellia oil, turtle oil, macadamia nut oil, corn oil, mink oil, olive oil, rapeseed oil, sesame oil, castor oil, linseed oil, safflower oil, jojoba oil, malt oil, coconut oil, palm oil, etc.

The silicone oil is not particularly limited. Examples of the silicone oil include methyl polysiloxane, methyl phenyl polysiloxane, methyl hydrogen polysiloxane, methyl polycyclo siloxane, etc.

The liquid higher fatty acid is not particularly limited. Examples of liquid higher fatty acids include oleic acid, isostearic acid, linoleic acid, and linolenic acid.

The liquid higher alcohol is not particularly limited. Examples of liquid higher alcohols include oleyl alcohol and isostearyl alcohol.

In addition, in order to increase the viscosity of the post-foamable composition after it has been filled into the discharge container and to further suppress the evaporation of the hydrofluoroolefin during discharge, it is preferable to blend a solid oil that is solid at 25°C, such as a solid hydrocarbon, a solid higher fatty acid, a solid higher alcohol, or an alkyl glucoside. When a solid oil is used, it is preferable to dissolve the solid oil in a liquid oil to make it liquid before use.

The solid hydrocarbon is not particularly limited. Examples of solid hydrocarbons include paraffin, beeswax, lanolin, candelilla wax, carnauba wax, etc. Among these, paraffin is preferable as the solid hydrocarbon because it can be easily prepared into a liquid oil and is easy to handle.

The solid higher fatty acid is not particularly limited. Examples of higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid.

The solid higher alcohol is not particularly limited. For example, the higher alcohol may be a straight-chain alcohol such as lauryl alcohol, cetyl alcohol, stearyl alcohol, behenyl alcohol, or myristyl alcohol, or a branched-chain alcohol such as lanolin alcohol, hexyldodecanol, cetostearyl alcohol, or octyldodecanol.

The alkyl glucoside is not particularly limited. Examples of the alkyl glucoside include cetearyl glucoside, decyl glucoside, lauryl glucoside, myristyl glucoside, alkyl (C8-16) glucoside, alkyl (C12-20) glucoside, arachyl glucoside, coconut oil glucoside, POE methyl glucoside, and POE methyl dioleate glucoside. The alkyl glucoside may be used in combination. Among these, the alkyl glucoside is preferably cetearyl glucoside, decyl glucoside, lauryl glucoside, myristyl glucoside, alkyl (C8-16) glucoside, alkyl (C12-20) glucoside, arachyl glucoside, coconut oil glucoside, and the like, and more preferably coconut oil glucoside, in view of the ease of emulsifying the aqueous concentrate and the hydrofluoroolefin to form a uniform phase.

When an oil is added, the content of the oil is not particularly limited. For example, the content of the oil in the post-foamable composition is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. The content of the oil in the post-foamable composition is preferably 10% by mass or less, and more preferably 8% by mass or less. When the content of the oil is within the above range, the viscosity increases slowly in the emulsification process, making it easier to form a uniform composition and to fill the emulsion. In addition, evaporation of the hydrofluoroolefin during discharge is suppressed, making it easier to discharge in a gel state.

Alcohol is preferably used as a solvent for active ingredients that are poorly soluble in water. It is also preferably used for purposes such as adjusting the foaming properties.

The alcohol is not particularly limited. For example, the alcohol may be a monohydric alcohol having 2 to 3 carbon atoms, such as ethanol or isopropanol, or a polyhydric alcohol, such as propylene glycol, 1,3-butylene glycol, hexylene glycol, dipropylene glycol, glycerin, or diglycerin.

When alcohol is blended, the content of alcohol is not particularly limited. For example, the content of alcohol in the post-foamable composition is preferably 1% by mass or more, and more preferably 3% by mass or more. The content of alcohol in the post-foamable composition is preferably 30% by mass or less, and more preferably 25% by mass or less. By having the alcohol content within the above range, the effect of blending alcohol is easily obtained, and the foamability of the post-foamable composition is less likely to be reduced by the alcohol.

Monosaccharides are preferably added for purposes such as adjusting the foaming properties.

The monosaccharides are not particularly limited. Examples of monosaccharides include sugar alcohols such as sorbitol, erythritol, arabitol, galactitol, glucitol, maltitol, mannitol, and xylitol; tetroses such as erythritol, D-erythrose, and D-threose; pentoses such as D-arabinose, L-arabinose, D-xylose, D-lyxose, L-lyxose, D-ribose, D-xylulose, L-xylulose, D-ribulose, and L-ribulose; and hexoses such as D-altrose, L-altrose, D-galactose, L-galactose, D-glucose, D-talose, D-mannose, L-sorbose, D-tagatose, D-psicose, and D-fructose.

When monosaccharides are blended, the content of the monosaccharides is not particularly limited. For example, the content of the monosaccharides in the post-foaming composition is preferably 0.5% by mass or more, and more preferably 1% by mass or more. The content of the monosaccharides in the post-foaming composition is preferably 20% by mass or less, and more preferably 15% by mass or less. When the content of the monosaccharides is within the above range, the effect of blending the monosaccharides is easily obtained.

Water-soluble polymers are preferably blended to increase the foaming properties of the post-foamable composition and to adjust the foam retention, hardness, elasticity, extensibility, etc.

The water-soluble polymer is not particularly limited. Examples of water-soluble polymers include dimethyl diallyl ammonium chloride (Polyquaternium 4), dimethyl diacryl ammonium chloride-acrylamide copolymer (Polyquaternium 7), chloride-O-[2-hydroxy-3-(trimethylammonio)propyl] hydroxyethyl cellulose (Polyquaternium 10), dimethyl diallyl ammonium chloride-acrylic acid copolymer (Polyquaternium 22), chloride-O-[2-hydroxy-3-(lauryldimethylammonio)propyl] hydroxyethyl cellulose (Polyquaternium 24), acrylamide-acrylic acid-dimethyl diallyl ammonium chloride copolymer (Polyquaternium 39), 2-methacryloyloxyethyl phosphorylcholine-butyl methacrylate copolymer liquid (Polyquaternium 51), N,N-dimethylaminoethyl diethyl methacrylate sulfate-N,N-dimethylacrylamide-dimethacrylate poly Cationic polymers such as ethylene glycol (polyquaternium 52), 2-methacryloyloxyethyl phosphorylcholine-stearyl methacrylate copolymer (polyquaternium 61), methacryloyloxyethylene phosphorylcholine, butyl methacrylate and sodium methacrylate (polyquaternium 65); cellulose-based polymers such as cellulose nanofiber, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose and sodium carboxymethylcellulose; gums such as xanthan gum, carrageenan, gum arabic, gum tragacanth, cationic guar gum, guar gum and gellan gum; dextran, sodium carboxymethyldextran, dextrin, pectin, sodium alginate, sodium hyaluronate, polyvinyl alcohol, carboxyvinyl polymer, etc.

When a water-soluble polymer is blended, the content of the water-soluble polymer is not particularly limited. For example, the content of the water-soluble polymer in the post-foamable composition is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more. The content of the water-soluble polymer in the post-foamable composition is preferably 5% by mass or less, and more preferably 3% by mass or less. By having the content of the water-soluble polymer within the above range, the effect of blending the water-soluble polymer is easily obtained, and the viscosity of the post-foamable composition does not become too high, and the foamability is not easily reduced.

Powder is ideally blended to improve the feel of the product, such as making it easier to slide on.

The powder is not particularly limited. Examples of the powder include talc, zinc oxide, titanium oxide, silica, zeolite, kaolin, mica, magnesium carbonate, calcium carbonate, zinc silicate, magnesium silicate, aluminum silicate, calcium silicate, etc.

When powder is blended, the powder content is not particularly limited. For example, the powder content in the post-foamable composition is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more. The powder content in the post-foamable composition is preferably 5% by mass or less, and more preferably 3% by mass or less. By having the powder content within the above range, the effect of blending the powder is easily obtained, and the post-foamable composition is less likely to clog the discharge passage when it is discharged.

The method for preparing the aqueous concentrate is not particularly limited. The aqueous concentrate can be prepared by a conventional method. For example, the aqueous concentrate can be prepared by adding a surfactant and optional ingredients such as an active ingredient and alcohol to water or warm water. In addition, when an oil is contained, the aqueous concentrate may be made into an emulsion.

The content of the aqueous concentrate in the post-foamable composition is preferably 60% by mass or more, and more preferably 65% by mass or more. The content of the aqueous concentrate in the post-foamable composition is preferably 95% by mass or less, and more preferably 90% by mass or less. When the content of the aqueous concentrate is within the above range, the post-foamable composition is more likely to form a uniform emulsion and is more likely to be discharged in a gel form.

Hydrofluoroolefins having a boiling point of 5 to 25° C. Hydrofluoroolefins having a boiling point of 5 to 25° C. are emulsified with an aqueous concentrate to form a post-foamable composition. When discharged from a discharge container to the outside, the hydrofluoroolefins having a boiling point of 5 to 25° C. are vaporized and used as a foaming agent that foams the aqueous concentrate.

The hydrofluoroolefin having a boiling point of 5 to 25°C is preferably trans-1-chloro-3,3,3-trifluoropropene (HFO-1233zd(E), boiling point 19°C). When discharged, the hydrofluoroolefin having a boiling point of 5 to 25°C is inhibited from vaporizing and becomes gel-like, and then gradually vaporizes and foams, so that the resulting foam is easy to spread and can be efficiently cooled by the heat of vaporization of the hydrofluoroolefin, making it easy to become cold.

The content of the hydrofluoroolefin having a boiling point of 5 to 25°C in the post-foamable composition is preferably 3% by mass or more, and more preferably 5% by mass or more. The content of the hydrofluoroolefin having a boiling point of 5 to 25°C in the post-foamable composition is preferably 30% by mass or less, and more preferably 25% by mass or less. By having the content of the hydrofluoroolefin having a boiling point of 5 to 25°C within the above range, the post-foamable composition is more likely to be discharged in a more stable gel-like form, gradually foams after being discharged, and an appropriate cooling sensation is more likely to be obtained.

In the post-foamable composition of this embodiment, other low-boiling point solvents may be used in combination as a foaming agent in addition to hydrofluoroolefins having a boiling point of 5 to 25°C. Examples of such low-boiling point solvents include hydrofluoroolefins having a boiling point of less than 5°C, such as trans-1,3,3,3-tetrafluoroprop-1-ene (HFO-1234ze, boiling point -19°C) and trans-2,3,3,3-tetrafluoroprop-1-ene (HFO-1234yf, boiling point -29°C), hydrofluoroolefins having a boiling point of more than 25°C, such as cis-1-chloro-3,3,3-trifluoropropene (HFO-1233zd(Z), boiling point 39°C), aliphatic hydrocarbons having 3 to 5 carbon atoms, such as propane, normal butane, isobutane, isopentane, and mixtures thereof, dimethyl ether, and liquefied gases such as mixtures thereof.

When a low-boiling solvent is blended, the content of the low-boiling solvent is not particularly limited. As an example, the content of the low-boiling solvent in the post-foamable composition is preferably 0.5% by mass or more, and more preferably 1% by mass or more. The content of the low-boiling solvent in the post-foamable composition is preferably 5% by mass or less, and more preferably 3% by mass or less. By having the content of the low-boiling solvent within the above range, the foaming state of the post-foamable composition can be easily adjusted.

(Compressed Gas)
The compressed gas may be blended as a pressurizing agent for discharging the post-foamable composition. The compressed gas is not particularly limited. Examples of the compressed gas include nitrogen, air, oxygen, hydrogen, carbon dioxide, and nitrous oxide.

When compressed gas is used, the compressed gas is preferably filled so that the pressure inside the discharge container at 25°C is 0.2 MPa or more, and more preferably 0.3 MPa or more. The compressed gas is preferably filled so that the pressure inside the discharge container at 25°C is 0.8 MPa or less, and more preferably 0.7 MPa or less. By filling the compressed gas so that the pressure is within the above range, the hydrofluoroolefin is likely to maintain a uniform emulsified state with the aqueous concentrate even inside the discharge container. Therefore, the post-foamable composition is likely to be discharged in a gel-like form.

Next, a method for producing a post-foamable composition containing the aqueous concentrate and a foaming agent will be described. The method for producing a post-foamable composition includes a degassing step for reducing the amount of air dissolved in the foaming agent to the saturated solubility amount or less at 25°C, an emulsification step for mixing the degassed foaming agent with the aqueous concentrate to emulsify, and a filling step for filling the obtained emulsion into a discharge container.

(Degassing process)
The degassing process is a process for reducing the amount of air dissolved in the foaming agent to the saturated solubility or less at 25° C. In the degassing process, the specific method for reducing the amount of air dissolved in the foaming agent to the saturated solubility or less at 25° C. in the degassing process is not particularly limited. As an example, the degassing process can be carried out by adopting a process such as a process of heating the foaming agent (hydrofluoroolefin) (heating process), a process of reducing the pressure inside a tank storing the hydrofluoroolefin (pressure reduction process), and a process of ultrasonically treating the hydrofluoroolefin (ultrasonic treatment process). Hereinafter, as an example, a case where a heating process is adopted will be illustrated.

(Heating process)
The heating step is a step of heating the blowing agent to above its boiling point, and is preferably carried out in the degassing step. The heating step can be carried out, for example, by filling a blowing agent containing hydrofluoroolefin in a storage container such as a tank and heating it to above the boiling point of the hydrofluoroolefin, or by heating it to above the boiling point of the hydrofluoroolefin in a pipe connected from the storage container to the emulsifier. This allows the air dissolved in the hydrofluoroolefin to be degassed and removed.

The reason for removing the air dissolved in the hydrofluoroolefin by degassing is as follows. That is, hydrofluoroolefin dissolves a large amount of compressed gas such as air. Therefore, when hydrofluoroolefin with a large amount of dissolved air is discharged to the outside, the dissolved air vaporizes and expands, which starts to promote the vaporization of the hydrofluoroolefin, making the discharged product more likely to foam. Therefore, in the past, it was impossible to discharge a discharged product containing hydrofluoroolefin in a gel state and then post-foam it by shearing or the like. However, in this embodiment, by adopting such a degassing process (warming process), the hydrofluoroolefin is heated to a temperature above the boiling point, thereby reducing the amount of dissolved air. As a result, even if the hydrofluoroolefin is discharged to the outside, the amount of dissolved air is less than that in the case where degassing is not performed, and vaporization is less likely to be promoted. As a result, the post-foamable composition produced by the manufacturing method of this embodiment can be discharged in a gel state with suppressed foaming during discharge.

In addition, by adopting a heating process, the manufacturing method of this embodiment makes it easy to adjust the amount of air dissolved in the foaming agent. In addition, the viscosity of the mixture of the aqueous concentrate and the foaming agent increases slowly in the emulsification process described below. Therefore, the aqueous concentrate and the foaming agent are easily mixed uniformly. As a result, the resulting post-foamable composition is easily discharged stably.

The heating step may include a discharge step of discharging gas from the container (storage container) containing the foaming agent or from the piping to the outside. By carrying out such a discharge step, the air dissolved in the foaming agent is easily discharged to the outside. This makes it possible to prevent the air from redissolving in the foaming agent. As a result, the resulting post-foamable composition is easily suppressed from foaming during discharge and is easily discharged in a gel state. The discharge step may be carried out by a known vent mechanism or the like.

(Emulsification process)
The emulsification step is a step of mixing and emulsifying the degassed foaming agent and the aqueous concentrate. The emulsification step can be carried out, for example, by sending the heated hydrofluoroolefin and the aqueous concentrate to a batch emulsifier or a continuous emulsifier, respectively, and mixing them.

When a heating step is employed in the degassing step, it is preferable that the aqueous concentrate is also heated to a temperature equal to or higher than the boiling point of the hydrofluoroolefin. This allows the viscosity of the mixture of the aqueous concentrate and the hydrofluoroolefin to increase slowly, making it easier to mix uniformly. As a result, the resulting post-foamable composition is easier to discharge stably.

In particular, the aqueous concentrate and the hydrofluoroolefin are preferably emulsified under conditions of 30 to 80°C, and more preferably under conditions of 35 to 70°C. This makes it more difficult for the viscosity of the mixture of the aqueous concentrate and the foaming agent to increase during the emulsification process. This makes it easier to maintain the temperature of the mixture, and to fill it into the discharge container. The filled mixture (post-foamable composition) is then more likely to increase in viscosity within the discharge container.

(Filling process)
The filling step is a step of filling the obtained emulsion into a discharge container, thereby obtaining a discharged product filled with the post-foamable composition.

The discharge container is not particularly limited. As an example, the discharge container is composed of a container body having an opening, a valve that seals the opening, and a discharge member that operates the valve to discharge.

The container body is a pressure-resistant container in which the post-foamable composition is filled. The container body may be a single container, or may be a double container consisting of an outer container and a flexible inner container housed within the outer container.

The material of one container or the outer container is not particularly limited. For example, the material may be metal such as aluminum or tinplate, various synthetic resins, pressure-resistant glass, etc. The inner container is not particularly limited. For example, the inner container may be a flexible container such as an inner bag made by blow-molding synthetic resin such as polyethylene, polyethylene terephthalate, EVAL, or nylon into a single-layer or multi-layer bag shape, or a pouch made by bonding together sheets of polyethylene, polyethylene terephthalate, aluminum, etc. Hydrofluoroolefins tend to foam when compressed gas dissolves in them. Therefore, it is preferable that the inner container is a multi-layer inner bag made of synthetic resin with gas barrier properties such as EVAL or nylon, or a laminated pouch made of a sheet of light metal such as aluminum.

The valve is a member for closing and sealing the opening of the container body. The valve mainly comprises a housing, a stem with a stem hole formed therein that communicates between the inside and outside of the container body, and a stem rubber attached around the stem hole to close the stem hole. The housing accommodates the stem. The stem is a substantially cylindrical part, and an internal stem passage is formed through which the post-foamable composition taken into the housing during discharge passes. A stem hole is formed near the lower end of the internal stem passage that communicates the space inside the housing with the internal stem passage. A discharge member for discharging the post-foamable composition is attached to the upper end of the stem. The stem rubber is a member attached around the stem hole to appropriately block the internal space of the housing from the outside. The stem rubber is a disc-shaped member, and when not being discharged, the inner peripheral surface of the stem is in close contact with the outer peripheral surface of the stem in which the stem hole is formed, to close the stem hole.

The discharge member is a member for discharging the post-foamable composition by opening and closing the valve, and is attached to the upper end of the stem. The discharge member mainly comprises a nozzle portion and an operating portion that is operated by the user with a finger or the like. The nozzle portion is a substantially cylindrical portion, and has a discharge passage through which the post-foamable composition passes. An opening (discharge hole) is formed at the tip of the discharge passage. The post-foamable composition is discharged from the discharge hole. The number and shape of the discharge holes are not particularly limited. There may be multiple discharge holes. The shape of the discharge hole may also be substantially circular, substantially angular, etc.

In the discharge product of this embodiment, when the discharge member is pressed down, the stem of the valve is pressed down. This causes the stem rubber to bend downward and the stem hole to open. As a result, the inside of the container body (inner container) is connected to the outside. When the inside of the container body is connected to the outside, the post-foamable composition is taken into the housing by the pressure difference between the pressure inside the container body and the outside, then passes through the stem hole and the stem internal passage, is sent to the discharge member, and is then discharged from the discharge hole.

As described above, according to the method for producing the post-foamable composition of this embodiment, the compressed gas (air) dissolved in the hydrofluoroolefin having a boiling point of 5 to 25°C is degassed by the degassing step. As a result, foaming originating from the dissolved air is easily suppressed in the discharged post-foamable composition. Therefore, the post-foamable composition can be discharged in a gel state. The post-foamable composition discharged in a gel state can be easily foamed by applying shear with a finger or the like.

The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples.

Example 1
According to the following recipe (unit: mass %), an aqueous stock solution was prepared in an emulsification tank, and the aqueous stock solution was heated and adjusted to 50°C. Hydrofluoroolefin (trans-1-chloro-3,3,3-trifluoropropene, HFO-1233zd(E)) with a boiling point of 19°C was used as a foaming agent, and the foaming agent was filled into an airtight tank and heated and adjusted to 50°C. The gas phase was discharged to the outside by the vent mechanism of the airtight tank to reduce the concentration of air dissolved in the hydrofluoroolefin (heating step, degassing step). The hydrofluoroolefin was injected into the emulsification tank so that the content of the post-foamable composition was 20% by mass, mixed with the aqueous stock solution, and emulsified (emulsification step). A valve and a container body equipped with a multi-layered pouch (polyethylene/aluminum/polyethylene) were used to pressurize the space between the container body and the pouch with nitrogen, and a double container was prepared by fixing the valve and sealing it. The emulsion (post-foamable composition) was filled from the emulsification tank into the pouch from the stem of the valve (filling step). The pressure inside the discharge vessel was 0.7 MPa (25° C.).

<Aqueous concentrate>
Liquid paraffin (*1) 2.0
Paraffin (*2) 2.0
Purified water 61.9
Oleth-20 (*3) 2.0
Cocamide DEA (*4) 5.0
Palmitic acid (*5) 6.8
Myristic acid (*6) 1.0
Glycerin (*7) 10.0
Sorbitol/water (*8) 5.0
Methylparaben (*9) 0.1
Triethanolamine (*10) 4.2
Total 100.0 (mass%)
*1: Hicol K-350 (trade name), manufactured by Kaneda Co., Ltd. *2: Paraffin Wax-125 (trade name), manufactured by Nippon Seiro Co., Ltd. *3: BO-20V (trade name), manufactured by Nikko Chemicals Co., Ltd. *4: Amizol CDE (trade name), manufactured by Kawaken Fine Chemical Co., Ltd. *5: Lunac P-95 (trade name), manufactured by Kao Corporation *6: Lunac MY-98 (trade name), manufactured by Kao Corporation *7: Concentrated Glycerin (trade name), manufactured by Kao Corporation *8: Sorbitol Kao (trade name), manufactured by Kao Corporation *9: Mekkins M (trade name), manufactured by Ueno Pharmaceutical Co., Ltd. *10: Triethanolamine-S (trade name), manufactured by Nippon Shokubai Co., Ltd.

Example 2
The temperature of the hydrofluoroolefin was adjusted by heating to 40°C, and the temperature of the aqueous concentrate was adjusted by heating to 40°C. In the same manner as in Example 1, except that the temperature was adjusted by heating to 40°C, the post-foamable composition was filled and a discharged product was produced.

Example 3
The temperature of the hydrofluoroolefin was adjusted by heating to 30°C, and the temperature of the aqueous concentrate was adjusted by heating to 30°C. In the same manner as in Example 1, except that the temperature of the hydrofluoroolefin was adjusted by heating to 30°C, the post-foamable composition was filled and a discharged product was produced.

Example 4
The temperature of the hydrofluoroolefin was adjusted by heating to 60°C, and the temperature of the aqueous concentrate was adjusted by heating to 60°C. In the same manner as in Example 1, except that the temperature of the hydrofluoroolefin was adjusted by heating to 60°C, the post-foamable composition was filled and a discharged product was produced.

Example 5
The post-foamable composition was filled and a discharged product was prepared in the same manner as in Example 1, except that the temperature of the hydrofluoroolefin was adjusted to 50°C and the temperature of the aqueous concentrate was adjusted to 25°C.

(Comparative Example 1)
The temperature of the hydrofluoroolefin was cooled and adjusted to 15°C, and the temperature of the aqueous concentrate was cooled and adjusted to 15°C. Except for this, the post-foamable composition was filled in the same manner as in Example 1 to prepare a discharged product.

Using the discharged products prepared in Examples 1 to 5 and Comparative Example 1, the discharged state of the post-foamable composition and the foaming state when shear was applied were evaluated by the following evaluation methods. The results are shown in Table 1.

<State of the material when discharged>
The discharged product was immersed in a thermostatic water bath adjusted to 25° C. for 1 hour, and the post-foamable composition was adjusted to 25° C. The discharged product was removed from the thermostatic water bath, and 1 g of the product was discharged onto the palm of a hand. The state of the post-foamable composition upon discharge was evaluated according to the following evaluation criteria.
(Evaluation criteria)
⊚: The post-foamable composition was discharged in the form of a transparent gel.
◯: The post-foamable composition was slightly cloudy but discharged in a gel state.
×: The post-foamable composition was discharged in a partially foamed gel state.

<State of extruded material after shearing>
After being dispensed onto the palm of the hand, the foamable composition was stirred with the fingers. After stirring, the state of the foamable composition was evaluated according to the following evaluation criteria.
(Evaluation criteria)
⊚: The post-foamable composition foamed slowly to form a uniform, finely grained foam.
◯: The post-foamable composition foamed slowly to form finely granular foam.
×: The post-foamable composition foamed slowly, but the size of the bubbles was uneven.

As shown in Table 1, the post-foamable compositions obtained by the manufacturing methods of Examples 1 to 5 were discharged in a transparent gel form and could be slowly foamed by stirring with fingers, resulting in finely granular foam. On the other hand, the post-foamable composition obtained by the manufacturing method of Comparative Example 1, in which the heating step (degassing step) was not performed, foamed when discharged and slowly foamed by stirring with fingers, but the size of the bubbles was uneven.

Claims (5)

A method for producing a post-foamable composition, comprising: an aqueous concentrate containing water and a surfactant; and a foaming agent containing a hydrofluoroolefin having a boiling point of 5 to 25°C,
a degassing step of reducing the amount of air dissolved in the foaming agent to a saturated solubility amount at 25°C or less;
an emulsification step of mixing the degassed foaming agent and the aqueous concentrate to emulsify;
and filling the obtained emulsion into a discharge container. The method for producing a post-foamable composition according to claim 1, wherein the degassing step includes a heating step of heating the foaming agent to a temperature equal to or higher than the boiling point. The method for producing a post-foamable composition according to claim 2, wherein the emulsification step is a step of heating the aqueous concentrate to a temperature equal to or higher than the boiling point of the foaming agent, and mixing the heated aqueous concentrate with the heated foaming agent. The method for producing a post-foamable composition according to claim 2 or 3, wherein the heating step includes a discharging step of discharging gas from a container or pipe containing the foaming agent to the outside. The method for producing a post-foamable composition according to any one of claims 1 to 4, wherein the emulsification step is a step of emulsifying the aqueous concentrate and the foaming agent at 30 to 80°C.