JP2012158546A - Near infrared inhibitor and method for evaluating inhibitory effect of near infrared ray - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new near infrared inhibitor capable of effectively inhibiting a near infrared ray.SOLUTION: The near infrared inhibitor contains a reflection component of a near infrared ray and the reflection component is formed by coating a metal particle dispersed in a hydrophobic solvent with a hydrophilic surfactant and/or an absorbing component of the near infrared ray. The absorbing component is formed by coating an outer layer of a water absorbing polymer coated with an oil phase or a hydrophilic surfactant with a polymeric emulsifier.

Description

  The present invention relates to a near-infrared inhibitor and a method for evaluating a near-infrared inhibitory effect using the near-infrared ray.

  Near-infrared rays with a long wavelength (wavelength range of about 800 to 2,500 nm) occupy about half of solar energy among solar rays, have high skin permeability, penetrate deep into the skin, and are in skin tissue. It is known to be absorbed by hemoglobin and water. Taking advantage of the properties of near-infrared light, near-infrared light is a medical infrared irradiation device for improving blood circulation, medical tools such as cerebral blood flow measurement, vein authentication, and optical interference from breast diagnostic equipment. It is widely used for diagnostic devices such as tomographic image diagnostic devices; heating equipment such as household heaters; cooking utensils;

  However, very recently, adverse effects on living bodies due to near infrared rays have been reported. For example, Patent Document 1 reports that long-term exposure to near infrared rays causes skin injuries such as skin erythema, blistering, thickening, and muscle tissue atrophy. It has also been reported that these skin disorders are caused by atrophy of muscle tissue (Non-Patent Document 1). Among solar rays, ultraviolet rays, which are known to cause skin damage such as sunburn, occupy only about 6 to 7% of solar energy, whereas near infrared rays are solar energy. Moreover, since it reaches the deep part of the skin, there is a strong concern that the near-infrared rays will adversely affect the living body.

  As one of skin disorders caused by near infrared rays, for example, photosensitivity can be mentioned. Photosensitivity is a rash that develops due to exposure of the skin to sunlight and is accompanied by itching. Photosensitivity is also called sunlight allergy, 1) endogenous (genetic factors) polyphyllosis, pellagra, urticaria, systemic lupus erythematosus, varicella-like blistering, 2) exogenous drug-induced photosensitivity, In addition to photocontact dermatitis, 3) polymorphic sun rash and chronic photodermatitis, the cause of which is completely unknown.

  Until now, photosensitivity has been considered as one of ultraviolet-dependent diseases. Therefore, diagnosis of photosensitivity is generally performed on the back of the back by UVA (wavelength: 315 nm to 400 nm) or UVB (wavelength: 280 nm to 315 nm). The sunscreen agent which inhibits ultraviolet rays is used for the prevention. However, since ultraviolet rays having a short wavelength reach only the surface layer of the skin, there are cases where sunburn (Sunburn) in which the skin is red and inflamed and suntan (Suntunning) in which melanin is deposited on the skin surface are caused by ultraviolet irradiation. However, it is difficult to think that apparent skin damage such as erythema and water bubbles develops only by ultraviolet irradiation, and the influence of near infrared rays reaching the deep part of the skin cannot be ignored.

  In fact, locally irradiated infrared therapy devices used for the treatment of neuritis, neuralgia, rheumatism, arthritis, bruises, sprains, muscle pain and back pain are contraindicated for use in patients with photosensitivity. It should be considered that the cause of photosensitivity is not only ultraviolet rays.

  In any case, whatever the mechanism of action of photosensitivity, light is still a direct inducer, and the development of effective inhibitors that can inhibit near infrared radiation is eagerly desired. Therefore, Patent Document 1 described above discloses a near-infrared damage preventing agent composed of titanium oxide and zinc oxide powder, and further improvement of the near-infrared inhibiting action is desired.

  In addition, as described above, near infrared rays penetrate deep into the skin and cause skin injury. Therefore, SPF (Sun Protection Factor) and PA (Protection Grade), which are international evaluation methods for UV inhibition, are used. The establishment of a simple and safe evaluation method that replaces human test methods such as of UVA (UVA protection index) is underway.

International Publication No. 2009/017104 Pamphlet

Tanaka Y, Matsuo K, Yuzuriha S .; Long-Lasting Muscle Thinning Induced by Infrared Irradiation Specialized With Wavelengths and Contact Cooling; A Preliminary Report. ePlasty. ; 2010; 10: e40

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a novel near-infrared inhibitor capable of effectively inhibiting near-infrared rays.

  Another object of the present invention is to provide a simple, safe and non-invasive method for evaluating near-infrared inhibition, which is an alternative to methods such as SPF and PA, which are international assessment methods for ultraviolet inhibition. It is to provide.

  The first near-infrared inhibitor according to the present invention that has achieved the above object (hereinafter sometimes abbreviated as first inhibitor) includes a near-infrared reflective component, and the reflective component is hydrophobic. The gist of the present invention is that the metal particles dispersed in the hydrophilic solvent are coated with a hydrophilic surfactant.

  In a preferred embodiment of the present invention, the metal particles are at least one selected from the group consisting of titanium oxide, zinc oxide, iron oxide, and talc.

  In a preferred embodiment of the present invention, the hydrophobic solvent is at least one selected from the group consisting of hexane, methylene chloride, and ethyl acetate.

  In preferable embodiment of this invention, the mass ratio of the said metal particle which occupies in a near-infrared inhibitor is 0.1% or more and 10% or less.

  Further, the second near-infrared inhibitor according to the present invention that has achieved the above object (hereinafter sometimes abbreviated as second inhibitor) includes a near-infrared absorbing component, and the absorbing component is The outer layer of the water-absorbing polymer coated with the oil phase or the hydrophilic surfactant is coated with a polymer emulsifier.

  In preferable embodiment of this invention, the mass ratio of the said water absorbing polymer in a near-infrared inhibitor is 0.1% or more and 50% or less.

  In addition, the third near-infrared inhibitor according to the present invention that has achieved the above object (hereinafter sometimes abbreviated as "third inhibitor") includes a near-infrared reflective component and a near-infrared absorbing component. The reflective component is a metal particle dispersed in a hydrophobic solvent coated with a hydrophilic surfactant, and the absorbing component is coated with an oil phase or a hydrophilic surfactant. The outer layer of the water-absorbing polymer is coated with a polymer emulsifier.

  In preferable embodiment of this invention, the mass ratio of the said water absorbing polymer in a near-infrared inhibitor is 0.1% or more and 50% or less.

  In a preferred embodiment of the present invention, the water-absorbing polymer is at least one selected from the group consisting of carboxyvinyl polymer, polyvinyl polymer, gellan gum, trehalose, sodium polyacrylate, and hyaluronic acid.

  In a preferred embodiment of the present invention, the hydrophilic surfactant is selected from the group consisting of polyoxyethylene hydrogenated castor oil, polyglyceryl monolaurate, polyglyceryl monostearate, glycerin fatty acid ester, and sucrose fatty acid ester polyglycerin fatty acid ester. Is at least one kind.

  In a preferred embodiment of the present invention, the oil phase is at least one selected from the group consisting of fats and oils, higher fatty acids, higher alcohols, and wax esters.

  In a preferred embodiment of the present invention, the polymer emulsifier is an acrylic acid / alkyl methacrylate copolymer.

  Further, the near-infrared inhibitory effect evaluation method according to the present invention that has solved the above problems is a method for evaluating the near-infrared inhibitory effect using the near-infrared inhibitor according to any one of the above, The gist is that the temperature difference between the application site of the infrared inhibitor and the non-application part is measured by thermography.

  If the 1st-3rd near-infrared inhibitor which concerns on this invention is used, compared with the conventional near-infrared inhibitor comprised only from the metal particle which is not masked, it was able to inhibit near infrared rays efficiently. . In particular, when an inhibitor containing a predetermined absorption component and a predetermined reflection component is used like the third inhibitor according to the present invention, it is closer than the first and second inhibitors containing these alone. Infrared rays could be inhibited even more efficiently.

  Moreover, if the evaluation method according to the present invention is used, the degree of inhibition of near infrared rays can be evaluated simply, safely and non-invasively.

FIG. 1 is a diagram schematically showing a configuration of a near-infrared inhibitor according to the present invention. FIG. 2 is a diagram schematically showing an inhibitory action (reflection / absorption) when the near-infrared inhibitor of the present invention is applied to the skin. FIG. 3 is a graph showing the relationship between the titanium oxide concentration and the near infrared ray inhibition rate when using each sample in Example 1. FIG. 4 is a graph showing the relationship between the concentration of the water-absorbing colloid and the near infrared ray inhibition rate in Example 2. FIG. 5 is a photograph obtained by measuring the effect of blocking near-infrared rays emitted from the skin surface by thermography in Example 3 using the near-infrared inhibitor of the present invention.

1. About the near-infrared inhibitor of this invention As mentioned above, the near-infrared inhibitor of this invention contains the 1st-3rd inhibitor.

  For reference, FIG. 1 schematically illustrates the near-infrared inhibitor. In short, the near-infrared inhibitor of the present invention contains metal particles masked as a near-infrared inhibitor in the water-containing base (W) or the water-containing base (O / W) containing an oil component (No. 1). 1), or a water-in-oil (W / O) type water-absorbing polymer gel as a near-infrared inhibitor (second or third inhibitor). . In (a) above, depending on the type of water-absorbing polymer, a hydrophilic surfactant may be used instead of an oil component (details will be described later), but in FIG. 1 and FIG. It is represented by.

  FIG. 2 schematically shows the inhibitory action (reflection / absorption) when the near-infrared inhibitor is applied to the skin. Among these, the characteristic part of the 1st near-infrared inhibitor (1st inhibitor) which concerns on this invention is a near-infrared reflective action (namely, the effect of having a high electron density and reflecting near-infrared without transmitting). Rather than using known metal particles such as titanium oxide and zinc oxide as a near-infrared inhibitor as they are, the metal particles are masked (wrapped with a water-soluble film). As a result, the metal particles can be prevented from flocing and the dispersibility is improved, so that the metal particles can be uniformly dispersed in the preparation. Therefore, when the inhibitor is applied to, for example, the skin, the skin surface is densely covered with the inhibitor, so that near infrared light that penetrates deep into the skin can be efficiently inhibited.

  In addition, the second near-infrared inhibitor (second inhibitor) according to the present invention does not use the near-infrared reflecting action as described above, but makes good use of the property that the near-infrared absorbs water. The water-absorbing polymer was masked [specifically, the water-containing gel (water-absorbing gel) of the absorbent polymer was wrapped in an oil phase, and the surrounding area was masked with a polymer emulsifier (a fat-soluble surfactant)). There is a feature.

  Moreover, the 3rd near-infrared inhibitor (3rd inhibitor) which concerns on this invention combines the reflective component and absorption component which comprise the 1st and 2nd inhibitor mentioned above. That is, the characteristic part of the third inhibitor does not cause the near-infrared inhibiting action to be expressed only by the near-infrared reflecting action or the absorbing action, unlike the first or second inhibitor described above. By the two-stage action of reflection and absorption, the near-infrared inhibitory action is remarkably enhanced as compared with the first or second inhibitor. According to the third inhibitor, it is possible to efficiently capture near-infrared rays that have passed through the gap between the reflection components and have been transmitted by the absorption component.

  Hereinafter, the constituent requirements of each inhibitor will be described in detail.

(1) 1st near-infrared inhibitor (1st inhibitor) which concerns on this invention
The first near-infrared inhibitor according to the present invention includes a near-infrared reflective component, and the reflective component is obtained by coating metal particles dispersed in a hydrophobic solvent with a hydrophilic surfactant.

(Metal particles)
The metal particles constituting the reflection component may be any one that reflects near-infrared rays, for example, at least one selected from the group consisting of titanium oxide, zinc oxide, iron oxide, and talc, which are widely used in cosmetics and the like. Is mentioned. These may be used alone or in combination of two or more. A commercial item may be used for these metal particles. Of these, titanium oxide and zinc oxide are preferred from the viewpoint of the near-infrared reflecting action (that is, the near-infrared inhibiting action), and titanium oxide is more preferred.

  A preferable average particle diameter of the metal particles is about 10 nm to 10 μm, and thereby a higher near infrared ray inhibiting action can be obtained. A more preferred upper limit is 100 nm or less, and even more preferred is 50 nm or less. Commercially available products may be used as the metal particles whose average particle diameter is controlled within the above range.

(Hydrophobic solvent)
The metal particles are dispersed in a hydrophobic solvent. Examples of the hydrophobic solvent used in the present invention include hexane, methylene chloride, ethyl acetate, benzene, toluene, diethyl ether, chloroform and the like. Among these, at least one selected from the group consisting of hexane, methylene chloride, and ethyl acetate is preferable. These may be used alone or in combination of two or more.

(Hydrophilic surfactant)
The present invention is characterized in that the metal particles dispersed in the above-described hydrophobic solvent are coated (masked) with a hydrophilic surfactant. Since metal particles are easy to make flocs, it is difficult to disperse them precisely in the preparation, but according to the present invention, since metal particles are coated with a hydrophilic surfactant, it is possible to prevent the formation of flocs of metal particles. As a result, the near-infrared inhibitory action by the metal particles is effectively exhibited.

  The hydrophilic surfactant used for masking preferably has a melting point of 25 ° C. or higher and an HLB value (Hydrophilic Lipophilic Balance) of 6.0 or higher.

  Examples of such hydrophilic surfactants include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. These may be used alone or in combination of two or more. Can be used.

  Among these, examples of the anionic surfactant include carboxylic acid type, sulfonic acid type, sulfate ester type, and phosphate ester type surfactants. Specifically, for example, fatty acid soap, naphthenic acid soap, long-chain alcohol sulfate, polyoxyethylene alkylphenyl ether sulfate, fatty acid monoglyceride sulfate, fatty acid monoalkanolamide sulfate, alkali sulfonate, α-sulfo Fatty acid salts, dialkyl sulfosuccinates, polyoxyethylene octyl phenyl ether sulfonates, alkyl benzene sulfonates, polyoxyethylene alkyl phenol ether phosphates, polyoxyethylene alkyl ether phosphates, sodium lauryl sulfate, etc. are used .

  Examples of the cationic surfactant include quaternary ammonium salt types, alkylamine salt types, and pyridine ring surfactants. Specifically, for example, a long-chain primary amine salt, alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkylpyridinium salt, polyoxyethylene alkylamine, and alkylimidazoline are used.

  Examples of the amphoteric surfactant include alkyl betaine type, fatty acid amidopropyl betaine type, alkyl imidazole type, amino acid type, and amine oxide type surfactants. Specifically, for example, N-alkyl β-aminopropionate, N-alkyl β-iminodipropionate and the like are used.

  Examples of the nonionic surfactant include ester type, ether type, ester ether type, alkanolamide type, alkyl glycoside type, and higher alcohol type surfactants. Specifically, for example, higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, Fatty acid ethylene oxide adducts, glycerin fatty acid esters, pentaerythritol fatty acid esters, polyhydric alcohol alkyl ethers, alkanolamine fatty acid amides, and the like are used.

  Among the hydrophilic surfactants mentioned above, sorbitol and sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyethylene glycol fatty acid ester, polyoxysorbitol fatty acid ester, sucrose fatty acid ester, polyoxyethylene castor oil, polyoxyethylene Hardened castor oil, polyoxyethylene polypropylene glycol copolymer, polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether, polyalkylene alkyl ether, glycerin fatty acid ester, polyglycerin fatty acid ester and the like are preferably used.

  Among these, as the polyoxyethylene sorbitan fatty acid ester, in particular, polyoxyethylene (6) sorbitan monostearate (for example, trade name: Rheodor TW-S106V, Kao Corporation), which is a polyoxyethylene sorbitan fatty acid ester, Polyoxyethylene sorbitan tristearate (for example, trade name: Rheodor TW-S320V, Kao Corporation) is more preferably used.

  Examples of the polyethylene glycol fatty acid ester include polyethylene glycol monostearate (for example, trade name: Emanon 3199V, Kao Corporation), polyethylene glycol distearate (for example, trade name: Emanon 3299V, Kao Corporation), Ethylene glycol distearate (for example, trade name: Emanon 3199RV, Kao Co., Ltd.) and polyoxyethylene hydrogenated castor oil are suitable. Among them, polyoxyethylene hydrogenated castor oil 40 (for example, trade name: Cremophor CO40, BASF Japan) Co., Ltd.), polyoxyethylene hydrogenated castor oil 60 (for example, trade name: Cremophor CO60, BASF Japan Ltd.) and the like are more preferably used.

  Further, as the polyoxyethylene polyoxypropylene glycol copolymer, polyoxyethylene (160) polyoxypropylene (30) glycol (for example, trade name: Emulgen PP-290, Kao Corporation) and the like are more preferably used. It is done.

  Examples of the sucrose fatty acid ester include sucrose palmitate esters (for example, trade name: P-1615, 1616, Mitsubishi Chemical Foods Co., Ltd.), sucrose myristate esters (for example, trade name: J-1416, Mitsubishi Chemical Foods Co., Ltd.) Sucrose stearates (eg, trade names: J-1809, 1811, 1811F, 1815, 1816, Mitsubishi Chemical Foods Co., Ltd.), sucrose laurates (eg, trade name: J -1216, Mitsubishi Chemical Foods Co., Ltd.), sucrose oleate (for example, trade name: J-1715, Mitsubishi Chemical Foods Co., Ltd.) and the like are more preferably used.

  Examples of the polyoxyethylene alkyl ether and the polyalkylene alkyl ether include polyoxyethylene lauryl ether (for example, trade name: Emulgen 123P, Kao Corporation), polyoxyethylene cetyl ether (for example, trade name: Emulgen 210, Kao). Co., Ltd.), polyoxyethylene stearyl ether (for example, trade name: Emulgen 320P, Kao Corporation), polyoxyethylene oleyl ether (for example, trade name: Emulgen 409V, 420, Kao Corporation) and the like are more preferably used. It is done.

  As the glyceric acid fatty acid ester, glycerol monostearate (for example, trade name: Rheidol MS-165V, Kao Corporation) is more preferably used.

  In addition to the above components, the first near-infrared inhibitor described above may contain additives ordinarily used in cosmetics and pharmaceuticals.

  In the first inhibitor, the mass ratio of the metal particles in the near-infrared inhibitor is preferably 0.1% or more and 20% or less. If the above ratio is less than 0.1%, the near-infrared reflecting action by the metal particles is not exhibited effectively. On the other hand, if it exceeds 20%, there is a problem of texture on the preparation such as elongation when applied. A more preferable mass ratio of the metal particles is 0.1% or more and 10% or less.

(Production method)
The first near-infrared inhibitor is obtained by dispersing the metal particles in the hydrophobic solvent, adding the hydrophilic surfactant, and heating and dissolving at a temperature of about 60 ° C. or more. Can be manufactured.

  Here, the mass ratio between the metal particles and the hydrophobic solvent differs depending on the type of the component used, and may be appropriately adjusted depending on the component, etc. It is preferable to add and disperse the organic solvent at a ratio of approximately equal to 50 times the amount.

  In addition, the ratio of the metal particles dispersed in this manner and the hydrophilic surfactant differs depending on the type of component used and the like, and may be appropriately adjusted appropriately according to the component. It is preferable to mask by adding a hydrophilic surfactant at a ratio of about 4 to 50 times with respect to 1 part by mass of the particles.

  In masking, it is preferable to dissolve the hydrophilic surfactant at a temperature of about 60 ° C. or higher. The upper limit is not particularly limited, but it is preferably about 150 ° C. or lower in view of the stability of the surfactant. The heating time varies depending on the ratio of metal particles and solvent constituting the inhibitor, the temperature, and the like, but it is preferable to control the heating time to about 30 minutes to 3 hours.

(2) Second near-infrared inhibitor according to the present invention (second inhibitor)
The second near-infrared inhibitor according to the present invention includes a near-infrared absorbing component, and the absorbing component is coated with an outer layer of a water-absorbing polymer coated with an oil phase or a hydrophilic surfactant with a polymer emulsifier. It has been done.

(Water-absorbing polymer)
Examples of the water-absorbing polymer used in the present invention include polyacrylate-based, polyvinyl alcohol-based, polyacrylamide-based, polyoxyethylene-based, starch-based, and cellulose-based synthetic polymers; water-soluble polymers; Examples include sugars. These may be used alone or in combination of two or more. Moreover, these can also use a commercial item.

  Among the polyacrylate polymers, a superabsorbent polymer (hereinafter referred to as “SAP”) having a cross-linked structure, having a water absorption capacity of 10 times or more of its own weight, and hardly releasing water even under pressure is preferable. Used.

  Specifically, as the synthetic polymer, a polyacrylate polymer compound such as sodium polyacrylate; a vinylpyrrolidone polymer compound such as polyvinylpyrrolidone or polyvinylpyrrolidone-vinyl acetate copolymer; carboxypolyvinyl alcohol; Vinyl alcohol polymer compounds such as polyvinyl alcohol and polyvinyl butyral; acidic vinyl ether polymer compounds such as vinyl methyl ether / butyl maleate; acrylic acid alkyl ester / methacrylic acid alkyl ester / diacetone acrylamide / methacrylic acid copolymer liquid, Acrylic acid polymer such as alkyl acrylate copolymer, acrylic acid / acrylic acid amide / ethyl acrylate copolymer; N-methacryloyloxyethyl-N, N-dimethylammo Amphoteric acrylic polymer such as um-α-N-methylcarboxybetaine / alkyl methacrylate copolymer, acrylic octylamide / hydroxypropyl acrylate / butylaminoethyl methacrylate copolymer; hydroxyethyl cellulose dimethyl diallylammonium chloride Copolymer: Hydroxyethylcellulose hydroxypropyltrimethylammonium chloride, vinylpyrrolidone / N, N'-dimethylaminoethyl methacrylic acid copolymer diethyl sulfate solution, homopolymer of dimethylallyl ammonium chloride, dimethyldiallylammonium chloride / acrylamide copolymer And nitrogen-containing cationic polymer compounds.

  In particular, carboxypolyvinyl alcohol, sodium polyacrylate, polyvinylpyrrolidone, carboxymethylcellulose and the like are suitable.

  Examples of water-soluble polymers include alginic acid, sodium alginate, chitosan, carrageenan, xanthan gum, locust bean gum, pullulan, pectin, gellan gum, gum arabic, hyaluronic acid, heparin, dermatan sulfate, chondroitin sulfate polyglutamic acid and collagen. The water-absorbing polymer is not limited to those listed here, and any water-absorbing polymer can be selected as long as it has water retention and can be used for pharmaceuticals, cosmetics, foods and the like.

  Furthermore, saccharides may be used in addition to these water-soluble polymers, and sugars such as disaccharides such as trehalose and sucrose, oligosaccharides such as galactooligosaccharide and fructooligosaccharide, glycerin, sorbitol, erythritol, xylitol, mannitol and the like However, the method of use is not limited to addition to the water-soluble polymer, and the use of saccharides themselves can also be selected.

  Among the water-absorbing polymers described above, at least one selected from the group consisting of carboxyvinyl polymer, polyvinyl polymer, gellan gum, trehalose, sodium polyacrylate, and hyaluronic acid is particularly preferable. These may be used alone or in combination of two or more.

  The water-absorbing polymer is coated with an oil phase or a hydrophilic surfactant.

(Hydrophilic surfactant)
Here, the said hydrophilic surfactant is as having demonstrated in the 1st inhibitor mentioned above.

(Oil phase)
Examples of the oil phase include at least one selected from the group consisting of fats and oils, higher fatty acids, higher alcohols, and wax esters (waxes). These may be used alone or in combination of two or more. Moreover, these can also use a commercial item.

  Among these, examples of the fats and oils include natural fats and oils and / or synthetic glycerides. It is preferable to use those having a melting point of 25 ° C. or higher.

  Specifically, as natural fats and oils used in the present invention, vegetable oils (palm oil, soybean oil, cottonseed oil, rapeseed oil, sesame oil, corn oil, peanut oil, safflower oil, sunflower oil, olive oil, perilla oil, shea butter, etc. ), Mineral oil, animal oil (beef tallow, pork oil, horse tallow, fish oil, etc.) can be used. Examples of the synthetic glyceride used in the present invention include hydrogenated vegetable oils such as hydrogenated castor oil having a melting point of 60 ° C. or higher, hydrogenated cottonseed oil, hydrogenated soybean oil, and glycerin fatty acid esters such as triacylglycerol. . These may be used alone or in combination of two or more.

  Examples of the higher fatty acid used in the present invention include lauric acid, myristic acid, palmitic acid, stearic acid, and isostearic acid.

  Examples of the higher alcohol used in the present invention include cetanol, stearyl alcohol, behenyl alcohol, and myristyl alcohol, and alkyl glyceryl ethers such as chimyl alcohol, ceralkyl alcohol, and batyl alcohol.

  Examples of the wax ester used in the present invention include beeswax, white wax, carnauba wax, cetyl palmitate and the like.

(Polymer emulsifier)
The outer layer of the water-absorbing polymer coated with the oil phase or hydrophilic surfactant described above (ie, around the oil phase or hydrophilic surfactant) is coated with a polymer emulsifier as shown in FIG. .

  Examples of the polymer emulsifier include, for example, acrylic acid / alkyl methacrylate copolymer, alkyl acrylate copolymer, polyacrylic acid, polyacrylic acid Na, polyalkyl acrylate, methyl methacrylate cross-polymer, (methyl vinyl ether / Maleic acid) crosspolymer, dextrin myristate, (palmitic acid / ethylhexanoic acid) dextrin, dextrin palmitate, inulin stearate and the like. These may be used alone or in combination of two or more. Moreover, these may use a commercial item. Of these, acrylic acid / alkyl methacrylate copolymers are preferred.

  In addition to the above components, the second near-infrared inhibitor described above may contain additives ordinarily used in cosmetics and pharmaceuticals.

  In the second near-infrared inhibitor, the mass ratio of the water-absorbing polymer in the near-infrared inhibitor is preferably 0.1% or more and 50% or less. If the ratio is less than 0.1%, the near-infrared absorbing action by the water-absorbing polymer is not effectively exhibited. On the other hand, if it exceeds 50%, there are problems in preparation such as gelation of the polymer. A more preferable mass ratio of the water-absorbing polymer is 0.1% or more and 20% or less.

(Production method)
The second near-infrared inhibitor can be produced as follows. First, the water-absorbing colloid containing sufficient water-absorbing polymer is dispersed by adding the above oil phase or hydrophilic surfactant, and the gel base (oil base) is added and mixed as appropriate. A functional polymer (masking). Subsequently, the desired inhibitor is obtained by adding the above-mentioned polymer emulsifier and emulsifying it.

  Hereinafter, each step will be described in detail.

  First, water-absorbing polymer is hydrated in water to obtain a water-absorbing colloid (hydrated gel). The water-containing conditions are different depending on the type of the water-absorbing polymer to be used, and it is difficult to uniquely describe, but generally, about 1 to 10 parts by weight of water is added to 1 part by weight of the water-absorbing polymer, Generally, it is preferable to leave it for 1 to 24 hours.

  Next, a hydrophilic surfactant is added to the water-absorbing colloid or an oil phase is added and dispersed. When adding an oil phase, it is preferable to dissolve by heating in advance. For example, it is preferable to heat and dissolve at a temperature of about 60 ° C. or higher (depending on the type, about 85 ° C. or higher), and then lower the temperature to about 40 to 60 ° C. to obtain a solution.

  Here, the mass ratio between the water-absorbing colloid (water-absorbing polymer added with water) and the hydrophilic surfactant or oil phase varies depending on the type of components used, but generally, the water-absorbing colloid It is preferable to add a hydrophilic surfactant or an oil phase in the range of about 4 to 50 parts by mass with respect to 1 part by mass of the colloid.

  For example, a mode in which an oil phase is added to the above water-absorbing colloid and dispersed is as follows. However, the present invention is not limited to this.

  For example, as one aspect, hydrogenated vegetable oils such as hydrogenated castor oil, hydrogenated cottonseed oil and hydrogenated soybean oil having a melting point of 60 ° C. or higher; and the oil phase of wax esters such as beeswax and carnauba wax are once heated to about 85 ° C. Then, after stirring and completely dissolving, medium chain fatty acid triglyceride and / or fat-soluble surfactant is added at a ratio of about 0.1 to 20 parts by mass with respect to 100 parts by mass of the oil phase. The solution is lowered to a temperature of about 40 to 60 ° C. while confirming the above.

  As another aspect, a predetermined solution may be obtained using a hydrophobic substrate (oil-based substrate). For example, a mixture of higher fatty acid ester triglyceride / diglyceride / monoglyceride (Sasol German GmbH; witepsol W-35, witepsol E85), which is a hydrophobic base material, is heated to about 85 ° C. and dissolved. On the other hand, after adding and dissolving about 1 to 30 parts by weight of beeswax, it may be lowered to a temperature of about 40 to 60 ° C. to obtain a fat and oil solution.

  Here, the oil-based substrate is preferably used for adjusting the melting point of the mixed fat or oil using a hard fat such as hardened oil or beeswax. The oily base is not particularly limited as long as it is a low-melting-point oil component usually used in pharmaceuticals, cosmetics, foods, etc. For example, vegetable oils, animal oils, neutral lipids (mono-substituted, di-substituted, or tri-substituted) Glyceride), synthetic fats and oils, sterol derivatives and the like.

  Examples of the oil component used in the oily base material include vegetable oils, mineral oils, petroleum jelly, paraffins, fats and oils composed of saturated fatty acids such as medium chain saturated fatty acids, unsaturated fatty acids, waxes, lanolin, glycerin fatty acid esters, propylene. Glycolic fatty acid ester, polyglyceryl monolaurate, polyglyceryl monostearate, glycerin fatty acid ester, sucrose fatty acid ester, polyethylene glycol monostearate, polyethylene glycol monolaurate, polyethylene glycol monooleate, polyoxyethylene sorbite monolaurate, polytetraoleate poly Oxyethylene sorbit, polyethylene glycol distearate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan isostearate Vitan, polyoxyethylene cholestanol ether, polyoxyethylene sorbitan monostearate, glyceryl polyoxyethylene oleate, polyoxyethylene coconut oil fatty acid sorbitan polyoxyethylene lauryl ether sodium phosphate, polyoxyethylene lanolin, polyoxyethylene alkyl ( 12-15) Ether phosphoric acid, polyoxyethylene glyceryl monostearate, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyoxyethylene lanolin alcohol, polyoxyethylene phytosterol , Polyoxyethylene polyoxypropylene cetyl ether, sorbitan fatty acid ester, lecithin Acetyl glycerine fatty acid ester, polyethylene glycol, propylene glycol, polyoxyethylene polyoxypropylene glycol, triethyl citrate, triacetin, myristyl alcohol, cetanol, stearyl alcohol, glycerol, ethanol and the like. These may be used alone or in combination of two or more.

  Of the oil components, polyglyceryl monolaurate, polyglyceryl monostearate, glycerin fatty acid ester, and sucrose fatty acid ester are preferable.

  Moreover, as vegetable oil used for the said oily base material, soybean oil, cottonseed oil, rapeseed oil, sesame oil, corn oil, peanut oil, safflower oil, sunflower oil, olive oil, perilla oil etc. are mentioned, for example.

  Moreover, as animal oil used for the said oil-based base material, beef tallow, pig oil, fish oil etc. are mentioned as animal oil, for example.

  Examples of the neutral lipid used in the oily base include triolein, trilinolein, tripalmitin, tristearin, trimyristin, triarachidonin, squalane and squalene.

  Moreover, as synthetic oil and fat used for the said oil-based base material, Azone etc. are mentioned, for example.

  Examples of the sterol derivative used for the oily substrate include cholesteryl oleate, cholesteryl linoleate, cholesteryl myristate, cholesteryl palmidate, and cholesrelyl arachidate.

  Among the above, preferable oil components for adjusting the melting point of the mixed oil using a hard fat include medium-chain fatty acid triglycerides and vegetable oils mainly composed thereof.

  Next, the masked water-absorbing colloid (water-absorbing polymer coated with the above-described oil phase or hydrophilic surfactant) thus obtained is added to the above-mentioned lipophilic emulsifier and emulsified to obtain the desired. To obtain a second inhibitor.

  Here, the preferred mass ratio of the water-absorbing colloid after coating and the lipophilic emulsifier varies depending on the types of components used, etc., but in general, the lipophilic emulsifier is generally added to 1 part by mass of the water-absorbing colloid. It is preferable to add in the range of 10 to 10 times the amount.

(3) Third near-infrared inhibitor (third inhibitor) according to the present invention
The third near-infrared inhibitor according to the present invention includes the above-described first inhibitor (near-infrared reflective component) and second inhibitor (near-infrared absorbing component). Details of the components constituting each inhibitor are as described above.

  In the third inhibitor, the mass ratio of the metal particles in the near-infrared inhibitor is preferably 0.1% or more and 20% or less. If the above ratio is less than 0.1%, the near-infrared reflecting action by the metal particles is not exhibited effectively. On the other hand, if it exceeds 20%, there is a problem of texture on the preparation such as elongation when applied. A more preferable mass ratio of the metal particles is 0.1% or more and 10% or less.

  In the third inhibitor, the mass ratio of the water-absorbing polymer in the near-infrared inhibitor is preferably 0.1% or more and 50% or less. When the above ratio is less than 0.1%, the near-infrared absorbing action by the water-absorbing polymer is not effectively exhibited, while when it exceeds 50%, there are problems in preparation such as gelation of the polymer. A more preferable mass ratio of the water-absorbing polymer is 0.1% or more and 20% or less.

  Further, in the third inhibitor, the above-described reflection component (in summary, masked metal particles) and the above-described absorption component (in summary, the outer layer of the water-absorbing polymer is coated with a hydrophilic surfactant. The mixture ratio (in terms of mass) of which the periphery is coated with a polymer emulsifier is preferably approximately reflective component: absorbing component = 0.1-20: 0.1-50, It is more preferable that it is 10: 0.1-20.

(Production method)
The third near-infrared inhibitor is produced by preparing the first and second inhibitors by the above-described method, adding them to the base material, mixing, kneading and the like. be able to.

  The base is not particularly limited as long as it is usually used for cosmetic gels, creams, lotions, bases for oil preparations, pharmaceuticals and the like.

  Here, in the preparation of the third inhibitor (further, the first and second inhibitors), the apparatus used for mixing and stirring is not particularly limited as long as a fine emulsified state can be obtained. It is possible to use those commonly used in the distribution of cosmetics and medicines. For example, a thin-film swirl type high-speed stirrer, a hydromax mixer, an impeller stirrer, an ajihomo mixer, and the like can be given. Specifically, for example, the above mixing and stirring steps can be performed using a nanomizer machine that is an ultra-high pressure emulsifier. Alternatively, instead of such mechanical stirring, a liquid phase laser ablation apparatus or an emulsification apparatus using ultrasonic waves may be used.

  The dosage form of the 1st-3rd inhibitor which concerns on this invention is not specifically limited, For example, a gel agent, a cream agent, an oil formulation, a lotion etc. can select a suitable dosage form suitably according to the intended purpose. it can.

2. About the near-infrared inhibitory effect evaluation method of this invention Next, the method to evaluate the near-infrared inhibitory effect is demonstrated. The evaluation method of the present invention is a method for evaluating the near-infrared inhibitory effect using the near-infrared inhibitor according to any one of the above, and the temperature difference between the application part of the near-infrared inhibitor and the non-applied part It is characterized by measuring with thermography.

  In this evaluation method, when the inhibitor is applied to the back of a human hand or the like, near-infrared rays radiated from the body surface are applied to each of the applied part (applied part) and the peripheral part not applied (non-coated part) This is based on the fact that the degree is different. The temperature of each part is measured by thermography, and the temperature difference between the two is evaluated as the near-infrared inhibitory effect of the inhibitor of the present invention. Here, thermography is a method of measuring near infrared rays emitted from an object using an infrared receiver and imaging the temperature distribution of the object. The temperature distribution of the measurement object can be easily and non-contacted. It is widely used as a method that can be measured.

  As shown in the examples described later, when the temperature difference between the application site and the non-application site of the inhibitor of the present invention was measured by thermography, a clear difference was observed between the two. Therefore, the evaluation method of the present invention for determining by thermography using the change in body surface temperature due to near-infrared irradiation as an index is extremely useful as a simple, safe and non-invasive method for evaluating the degree of inhibition of near-infrared rays. .

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples, and can be implemented with modifications within a range that can meet the purpose described above and below. They are all included in the technical scope of the present invention.

Production Example 1 Preparation of first inhibitor (1)
A polyoxyethylene cured material in which 50 g of titanium oxide having an average particle size of 25 nm (Ishihara Sangyo Co., Ltd., TTO-51 (C)) was dispersed in 80 g of hexane and then heated to 85 ° C. and dissolved. An inhibitor (only reflective component) of Production Example 1 was obtained by adding to a solution of castor oil (Nikko Chemicals Co., Ltd., HCO-60) 100 g, stirring, and removing the solvent by drying under reduced pressure using an evaporator.

Production Example 2 Preparation of first inhibitor (2)
A solution of 180 g of polyoxyethylene hydrogenated castor oil (Nikko Chemicals Co., Ltd., HCO-60) in which 20 g of zinc oxide (Ishihara Sangyo Co., Ltd. FZO-50) having an average particle size of 21 nm is heated to 85 ° C. and dissolved. In addition to the above, the mixture was stirred and the solvent was removed by drying under reduced pressure using an evaporator to obtain the inhibitor of Production Example 2 (only the reflection component).

Production Example 3 Preparation of second inhibitor (1)
After adding 19 g of purified water to 1 g of Carbomer 980 (Nikko Chemicals Co., Ltd., a kind of carboxyvinyl polymer) and immersing it overnight, it was swollen and heated to 85 ° C. to dissolve shea butter RF (high grade) In addition to 80 g of Alcohol Industry Co., Ltd., the mixture was stirred and dispersed. This dispersion (water-absorbing colloid) is occupying in a 3% by mass aqueous solution of acrylic acid / alkyl methacrylate copolymer (Nikko Chemicals, PEMULEN TR-1) dissolved at 85 ° C. with heating. In addition, the inhibitor of Production Example 3 (only the absorbing component) was obtained by stirring and dispersing the mixture so that the ratio was 10% by mass (that is, the content of water-absorbing colloid was 10%).

Production Example 4 Preparation of second inhibitor (2)
After adding 19 g of purified water to 1 g of Rubiscol K30 (BASF Japan Co., Ltd., a kind of polyvinylpyrrolidone) and swelled by immersion overnight, this was heated to 85 ° C. and dissolved in polyoxyethylene cured castor A solution of 80 g of oil (Nikko Chemicals Co., Ltd., HCO-60) was added and stirred to disperse. This dispersion was heated to 85 ° C. and dissolved in an acrylic acid / methacrylic acid alkyl copolymer (Nikko Chemicals Co., Ltd., PEMULEN TR-1) 3 mass% aqueous solution. The inhibitor (only the absorption component) of Production Example 4 was obtained by adding, stirring, and dispersing so as to be 10% by mass.

Production Example 5 Preparation of second inhibitor (3)
19 g of purified water is added to 0.5 g of xanthan gum (Dainippon Pharmaceutical Co., Ltd .; trade name Echo Gum / Celtrol) and 0.25 g of purified locust bean gum (trade name: GENUGUM type RL-200-J). After being immersed overnight and allowed to swell with water, it was added to 80 g of Shea Butter RF (Higher Alcohol Industry Co., Ltd.) dissolved by heating at 85 ° C. and stirred to disperse. This dispersion was heated to 85 ° C. and dissolved in an acrylic acid / methacrylic acid alkyl copolymer (Nikko Chemicals Co., Ltd., PEMULEN TR-1) 3 mass% aqueous solution. The inhibitor (only the absorption component) of Production Example 5 was obtained by adding 10% by mass, stirring and dispersing.

Production Example 6: Preparation of second inhibitor (4)
Carrageenan (manufactured by Sanki Co., Ltd .; trade name GENUGEL carriage type type SWG-J) 0.5 g and refined locust bean gum (manufactured by Sanki Co., Ltd .; trade name GENUGUM type RL-200-J) 0.25 g and purified water 19 g After being immersed overnight and allowed to swell with water, it was added to 80 g of Shea butter RF (Higher Alcohol Industry Co., Ltd.) dissolved by heating at 85 ° C. and stirred to disperse. This dispersion was heated and dissolved at 85 ° C. in an acrylic acid / methacrylic acid alkyl copolymer (Nikko Chemicals Co., Ltd., PEMULEN TR-1) 3 mass% aqueous solution with a ratio of 10 mass in the total solution. %, And the mixture was stirred and dispersed to obtain the inhibitor of Production Example 6 (absorbing component only).

Production Example 7 Preparation of second inhibitor (5)
0.5 g of pectin (manufactured by Sanki Co., Ltd .; trade name GENU lectin type 121-J Slow Set) was dispersed in 10 g of glycerin, and 10 g of boiled sucrose 80% solution was added and dissolved. While keeping this solution at 85 ° C., it was added to 80 g of heated shea butter RF (Higher Alcohol Industry Co., Ltd.) and stirred and dispersed. This dispersion was heated and dissolved at 85 ° C. in an acrylic acid / methacrylic acid alkyl copolymer (Nikko Chemicals Co., Ltd., PEMULEN TR-1) 3 mass% aqueous solution with a ratio of 10 mass in the total solution. %, And the mixture was stirred and dispersed to obtain the inhibitor of Production Example 7 (absorbing component only).

Production Example 8 Preparation of second inhibitor (7)
0.3 g of sodium alginate (Kimika Co., Ltd .; Kimika Algin IL-6 g) was dispersed in 2 g of glycerin, and 14 g of boiled water was added and dissolved. While keeping this solution at 85 ° C., it is added to 80 g of heated shea butter RF (High Alcohol Industry Co., Ltd.) and stirred and dispersed. While dispersing, slowly add 3 g of 1% aqueous calcium chloride solution at 1 mL per minute. This dispersion was added to a 3% by weight aqueous solution of an acrylic acid / alkyl acrylate copolymer (Nikko Chemicals, PEMULEN TR-1) dissolved at 85 ° C. with heating, stirred and dispersed. The inhibitor of Production Example 8 (absorbing component only) was obtained.

Production Example 9 Preparation of second inhibitor (8)
0.7 g of gellan gum (manufactured by Sanki Co., Ltd .; Kelcogel AFT) was dispersed in 2 g of glycerin, and 16.3 g of boiled water was added and dissolved. While maintaining this solution at 85 ° C., it was added to a solution of 80 g of polyoxyethylene hydrogenated castor oil (Nikko Chemicals Co., Ltd., HCO-60) dissolved by heating to 85 ° C., and the mixture was stirred and dispersed. This dispersion was heated to 85 ° C. and dissolved in an acrylic acid / methacrylic acid alkyl copolymer (Nikko Chemicals Co., Ltd., PEMULEN TR-1) 3 mass% aqueous solution. The inhibitor of Production Example 9 (absorbing component only) was obtained by adding to 10% by mass, stirring and dispersing.

Production Example 10: Preparation of third inhibitor (1)
To 3450 g of purified water, 150 g of glycerin and 20 g of carbomer 980 (Nikko Chemicals Co., Ltd., a kind of carboxyvinyl polymer) were added, and the mixture was stirred and dissolved while heating at 85 ° C. After the temperature was lowered to 65 ° C., 200 g of olive squalane, 150 g of jojoba oil, and 30 g of phenoxyethanol were added and mixed. The temperature was further lowered to 40 ° C., 50 g of 10% NaOH was added and stirred, and then the temperature was lowered to 25 ° C. To this, 450 g of the inhibitor of the above Production Example 1 (first inhibitor) and 500 g of the inhibitor of the above Production Example 3 (second inhibitor) are added, and then stirred and dispersed to make Production Example 10 Inhibitors (reflection component + absorption component) were obtained.

Production Example 11 Preparation of first inhibitor (2)
To 3950 g of purified water, 150 g of glycerin and 20 g of carbomer 980 (Nikko Chemicals Co., Ltd., a kind of carboxyvinyl polymer) were added, and the mixture was stirred and dissolved while heating at 85 ° C. After the temperature was lowered to 65 ° C., 200 g of olive squalane, 150 g of jojoba oil, and 30 g of phenoxyethanol were added and mixed. The temperature was further lowered to 40 ° C., 50 g of 10% NaOH was added and stirred, and then the temperature was lowered to 25 ° C. The inhibitor of the said manufacture example 1 (1st inhibitor) was added there, Then, the inhibitor of the manufacture example 11 (only a reflective component) was obtained by stirring and disperse | distributing.

Production Example 12: Preparation of metal particles (without masking) (Comparative Example)
150 g of glycerin and 20 g of Carbomer 980 (Nikko Chemicals, Inc., a kind of carboxyvinyl polymer) were added to 4250 g of purified water, and the mixture was stirred and dissolved while heating at 85 ° C. After the temperature was lowered to 65 ° C., 200 g of olive squalane, 150 g of jojoba oil, and 30 g of phenoxyethanol were added and mixed. The temperature was further lowered to 40 ° C., 50 g of 10% NaOH was added and stirred, and then the temperature was lowered to 25 ° C. To this, 150 g of titanium oxide having an average particle size of 25 nm (Ishihara Sangyo Co., Ltd., TTO-51 (C)) was added, stirred, and dispersed to obtain Production Example 12 (Comparative Example).

Production Example 13: Preparation of oil phase (base) only for first inhibitor (control example)
To 4100 g of purified water, 150 g of glycerin and 20 g of Carbomer 980 (Nikko Chemicals Co., Ltd., a kind of carboxyvinyl polymer) were added and stirred while heating at 85 ° C. to dissolve. After the temperature was lowered to 65 ° C., 200 g of olive squalane, 150 g of jojoba oil, and 30 g of phenoxyethanol were added and mixed. The temperature was further lowered to 40 ° C., 50 g of 10% NaOH was added and stirred, and then the temperature was lowered to 25 ° C. Thereto, 300 g of polyoxyethylene hydrogenated castor oil (Nikko Chemicals Co., Ltd., HCO-60) was added, stirred and dispersed to obtain Production Example 13 (Comparative Example).

Production Example 14: Preparation of only the second inhibitor (base) (control example)
To 3600 g of purified water, 150 g of glycerin and 20 g of carbomer 980 (Nikko Chemicals Co., Ltd., a kind of carboxyvinyl polymer) were added, and the mixture was stirred and dissolved while heating at 85 ° C. After the temperature was lowered to 65 ° C., 200 g of olive squalane, 150 g of jojoba oil, and 30 g of phenoxyethanol were added and mixed. The temperature was further lowered to 40 ° C., 50 g of 10% NaOH was added and stirred, and then the temperature was lowered to 25 ° C. Into this, 300 g of polyoxyethylene hydrogenated castor oil (Nikko Chemicals Co., Ltd., HCO-60) was added, stirred and dispersed to obtain Production Example 14.

Production Example 15: Preparation of Second Inhibitor Manufactured by adding 500 g of the inhibitor (second inhibitor) of Production Example 3 to the base of Production Example 14, followed by stirring and dispersing. Example 15 (second inhibitor) was obtained.

Example 1 Evaluation of Near Infrared Inhibitory Effect (1)
The production example 10 (third inhibitor) and the production example 11 (second inhibitor) are used as test samples, the production example 12 is used as a comparative sample, and UV / visible manufactured by Shimadzu Corporation.・ The near-infrared spectrophotometer UV-3600 scans the near-infrared region (800 nm to 2,500 nm) at a pitch of 2 nm and receives light using a large sample chamber with an integrating sphere attached to the spectrophotometer. The permeation amount of each sample was determined. Using the above Production Example 13 as a standard sample, the amount of permeation was measured in the same manner as described above, and the amount of permeation of the test sample and the comparative sample was corrected.

The inhibition rate of near infrared rays (nIR, 800 nm to 2,500 nm) was calculated as follows.
nIR inhibition rate (%)
= [Permeation amount of test sample (A _t ) / permeation amount of standard sample (A _s )] × 100

  These results are shown in FIG. The vertical axis in FIG. 3 represents the near infrared ray inhibition rate (%), and the horizontal axis represents the titanium oxide concentration (%). FIG. 3 also shows the results when the titanium oxide concentration was variously changed for each sample.

  From FIG. 3, when the third inhibitor (Production Example 10, in the figure, ◆) and the first inhibitor (Production Example 11, in the figure) according to the present invention are used, it depends on the titanium oxide concentration. It can be seen that the near-infrared inhibition rate is improved. On the other hand, in Production Example 12 (indicated by ▲ in the figure) using untreated titanium oxide that was not subjected to masking treatment, even if the titanium oxide concentration was changed, almost no inhibitory effect was obtained. Therefore, it was demonstrated that the near-infrared inhibiting effect is improved by masking titanium oxide.

  Furthermore, when the third inhibitor (Production Example 10) and the first inhibitor (Production Example 11) are compared, when an absorption component (water-absorbing colloid) is added as in the case of the third inhibitor, the first inhibitor It was found that the inhibitory effect was further improved compared to. Therefore, it was proved that near-infrared rays can be extremely effectively inhibited by reflection by masked titanium oxide and absorption by a water-absorbing colloid using a water-absorbing gel.

Example 2 Evaluation of Near-Infrared Inhibitor (2)
The inhibition rate was determined in the same manner as in Example 1 using Production Example 15 (second inhibitor) as a test sample and Production Example 14 as a standard sample.

  The result is shown in FIG. FIG. 4 also shows the results when the content of the water-absorbing colloid is variously changed.

  From FIG. 4, it was found that when the second inhibitor according to the present invention (♦ in the figure) was used, the near-infrared inhibition rate was improved depending on the content (%) of the water-absorbing colloid.

Example 3 Evaluation by Thermography Here, it was measured how much the infrared rays emitted from the skin surface can be blocked by the inhibitor of the present invention.

  Specifically, 0.5 g of the inhibitor of Production Example 10 (first inhibitor) is applied to the left back of a healthy adult in a range of 25 mm × 25 mm, and the skin temperature after application is separated from the application surface by 30 cm. The images were taken using a thermography (CPA-B0306 from FLIR systems manufactured by CHINO). For comparison, the skin temperature of the non-application part around the application part was photographed in the same manner.

  These results are shown in FIG. FIG. 5 shows thermographic photographs before application, immediately after application, 10 minutes after application, and 20 minutes after application.

  As shown in FIG. 5, before the inhibitor of the present invention (Production Example 5) was applied, the back side of the left hand was at a uniform temperature as a whole, whereas after application, the inhibitor was released from the skin surface. Since the infrared rays to be shielded are cut off, the temperature of the coating part was lowered. Therefore, it can be seen that the inhibition effect of the near-infrared inhibitor can be evaluated non-invasively by using the method of the present invention.

  As described above, when near-infrared rays are exposed to human skin for a long time, erythema and water bubbles develop, but in other words, the influence of near-infrared rays can be confirmed by the onset of such skin injury. However, there has been no evaluation method based on whether or not human skin injury is suppressed, and a non-invasive evaluation method has been demanded. The evaluation method according to the present invention responds excellently to such a request, and can be said to be an extremely effective method for human tests that is simple and reproducible and that can evaluate and determine the influence of near infrared rays.

Claims (13)

Contains a near infrared reflection component,
The near-infrared inhibitor, wherein the reflection component is a metal particle dispersed in a hydrophobic solvent coated with a hydrophilic surfactant.   The near-infrared inhibitor according to claim 1, wherein the metal particles are at least one selected from the group consisting of titanium oxide, zinc oxide, iron oxide, and talc.   The near-infrared inhibitor according to claim 1 or 2, wherein the hydrophobic solvent is at least one selected from the group consisting of hexane, methylene chloride, and ethyl acetate.   The near-infrared inhibitor according to any one of claims 1 to 3, wherein a mass ratio of the metal particles in the near-infrared inhibitor is 0.1% or more and 20% or less. Contains a near-infrared absorbing component,
The near-infrared inhibitor, wherein the absorbing component is an outer layer of a water-absorbing polymer coated with an oil phase or a hydrophilic surfactant, coated with a polymer emulsifier.   The near-infrared inhibitor according to claim 5, wherein a mass ratio of the water-absorbing polymer in the near-infrared inhibitor is 0.1% to 50%. Including a near-infrared reflective component and a near-infrared absorbing component,
The reflective component is one in which metal particles dispersed in a hydrophobic solvent are coated with a hydrophilic surfactant,
The near-infrared inhibitor, wherein the absorbing component is an outer layer of a water-absorbing polymer coated with an oil phase or a hydrophilic surfactant, coated with a polymer emulsifier.   The near-infrared inhibitor according to claim 7, wherein a mass ratio of the water-absorbing polymer in the near-infrared inhibitor is 0.1% to 50%.   The near-infrared ray inhibition according to any one of claims 5 to 8, wherein the water-absorbing polymer is at least one selected from the group consisting of carboxyvinyl polymer, polyvinyl polymer, gellan gum, trehalose, sodium polyacrylate, and hyaluronic acid. Agent.   The hydrophilic surfactant is at least one selected from the group consisting of polyoxyethylene hydrogenated castor oil, polyglyceryl monolaurate, polyglyceryl monostearate, glycerin fatty acid ester, and sucrose fatty acid ester polyglycerin fatty acid ester. The near-infrared inhibitor which consists of a metal compound in any one of 1-9.   The near-infrared inhibitor according to any one of claims 5 to 10, wherein the oil phase is at least one selected from the group consisting of fats and oils, higher fatty acids, higher alcohols, and wax esters.   The near-infrared inhibitor according to claim 5, wherein the polymer emulsifier is an acrylic acid / alkyl methacrylate copolymer. A method for evaluating the near-infrared inhibitory effect using the near-infrared inhibitor according to claim 1,
A method for evaluating a near-infrared inhibitory effect, characterized by measuring by a temperature difference thermography between a site where a near-infrared inhibitor is applied and a non-coated portion.