JPH09221408A - Melanin pigment decomposing substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new melanin pigment decomposing substance by using a specific substance having properties capable of acting on a melanin pigment contained in a microorganism, a plant, an animal, etc., and depolymerizing or decomposing the pigment. SOLUTION: An optical semiconductive substance is used. Zinc oxide, titanium dioxide, tungsten oxide, silicone, a polyacetylene, polythiophene, etc., may be cited as the optical semiconductive element. Titanium dioxide is especially preferable. The melanin pigment decomposing effect is improved by further adding a small amount of electroconductive powder to the optical semiconductive substance. Carbon black, silver, copper, etc., may be cited as the electroconductive powder. Tin oxide containing 0.1-20wt.% of antimony oxide is preferable due to high electroconductivity. The amount of the electroconductive substance is preferably about 1-100 pts.wt. based on 100 pts.wt. of the optical semiconductive substance. When the optical semiconductive substance is coated with a porous substance and used, advantageously deterioration caused by contact of the optical semiconductive substance with a base component can be avoided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a melanin pigment decomposing substance.

[0002]

BACKGROUND OF THE INVENTION Melanin is a high-molecular substance having a black to brown color that is synthesized by the action of an oxidase called polyphenol oxidase using a phenolic compound such as tyrosine or dihydroxyphenylalanine (dopa) as a substrate. Widely distributed in nature such as animals. BACKGROUND ART Conventionally, many products in which sodium hypochlorite is blended are used for decolorizing melanin pigments such as mold attached to the surfaces of walls, tiles, plastics, joints and the like in houses. Although sodium hypochlorite has a high decolorizing effect and is inexpensive, it may generate chlorine gas when mixed with other products containing an acid. This chlorine gas is harmful to the human body, and if it is generated in a closed room, it may be dangerous to the human body, and it is necessary to exercise caution when using it.

When human beings are exposed to strong ultraviolet rays, melanin pigments are produced on the skin, which absorbs harmful ultraviolet rays and prevents a deeper area from reaching a so-called biological defense mechanism. However, abnormal production of local melanin pigment causes spots and freckles. In order to suppress the excessive production of this melanin pigment, inhibitors for arbutin, kojic acid, ascorbic acid and other enzymes involved in the production of melanin pigment have been used. These substances do not have the effect of decomposing the melanin pigment once produced. On the other hand, as a low molecular weight compound that decomposes a melanin pigment, a melanin-decomposing substance extracted from seaweed is disclosed (JP-A-3-251514), but it has not been put to practical use.

[0004]

The present invention provides a novel melanin pigment decomposing substance.

[0005]

The melanin-decomposing substance of the present invention is characterized by containing a photo-semiconductor.

<Photosemiconductor> As the photosemiconductor of the present invention, zinc oxide, titanium dioxide (hereinafter, simply referred to as "titanium oxide"), tungsten oxide, styrontium titanate, ferric oxide. Metal oxides such as; metal chalcogenides such as zinc sulfide, cadmium sulfide, lead sulfide, zinc selenide, cadmium selenide; Group IV elements such as silicon and germanium; gallium-phosphorus, gallium-arsenic, indium-phosphorus, etc. Group III-V compounds; organic semiconductors such as polyacetylene, folipyrrole, polythiophene, polyaniline, and polyvinylcarbazole.

Of the above-mentioned photo-semiconductors, metal oxides such as titanium oxide and tungsten oxide are preferable from the practical viewpoint. Titanium oxide is the easiest to use because it is easily available.Amorphous, rutile, and anatase types are known, but any of them can be used, and when used for antibacterial purposes, anatase-type oxidation Titanium has the best antibacterial activity. Further, in many cases, titanium oxide, which is generally used as a white pigment, is not preferable because the surface thereof is completely covered with alumina or silica, which lowers the photocatalytic action. The above-mentioned photo-semiconductors may be used alone or in combination of two or more kinds.

<Conductive Material> The above-mentioned photo-semiconductive material is used together with a conductive material to improve its catalytic effect. As the conductive substance, carbon powder or fibrous carbon, which is generally used for imparting conductivity, metal powder or fibrous metal, can be used. Examples include carbon black, silver, copper, gold, iron, aluminum, nickel, platinum, palladium, tin oxide, indium oxide and the like. Alternatively, a non-conductor may be used as a core material and the surface thereof may be coated with a conductor. Examples thereof include silver-plated fine particles, aluminum-coated fine particles, and barium sulfate fine particles whose surface is coated with tin oxide.

Among the above conductive materials, tin oxide fine particles, which are easily available and are relatively inexpensive, and barium sulfate fine particles whose surface is coated with tin oxide are preferable from the practical viewpoint.
Tin oxide to which 0.1 to 20% by weight of antimony oxide is added exhibits high conductivity and is preferably used.

The amount of the conductive material added to the light semiconducting material is 1 to 100 with respect to 100 parts by weight of the light semiconducting material.
It is preferably in parts by weight. If the amount is less than this, the effect of adding the conductive substance is difficult to recognize. If the amount is larger than this, the effect is not further increased, but it does not hinder the photocatalytic effect, and when it is also used as the carrier of the photo-semiconductor, the addition amount may be increased. .

<Coating with Porous Material> Since the photo-semiconductor material is generally a fine powder, it is often necessary to immobilize it for use. However, the photo-semiconductor is
When left in direct contact with a substrate constituent component such as an organic polymer that is generally widely used, it has a problem of degrading the organic polymer or the like. The above-mentioned deterioration is considered to be caused by radicals generated during the photocatalytic reaction by the photo-semiconductor.

When used for the purpose of removing spots and freckles, which is one of the application fields of melanin pigment decomposition,
It is expected that radicals will cause rough skin when the photoconductive substance comes into direct contact with the skin.

In a mode of utilization in which the generation of radicals is not preferable as described above, as a means for exerting a catalytic action without directly contacting the photo-semiconductor with the substrate constituent components, skin, etc., A photo-semiconductor material can be coated with a porous material for use. Examples thereof include porous microcapsules containing a photo-semiconductor material, a so-called sandwich structure in which a photo-semiconductor material is sandwiched between layers made of a porous material, and the like.

Depending on the mode of use, it is not necessary for the porous material to cover the entire surface of the light semiconducting material. If the base component does not need to consider the problem of deterioration, a light semiconducting substance is supported on the surface of the substrate, and the surface of the substrate is coated with a porous substance only on the surface. It can give melanin pigment decomposing ability and prevent the photo-semiconductor from being exposed on the surface. According to this method
Compared with the case where the optical semiconductor is dispersed in the entire base material, a small amount of the light semiconductive material can be efficiently used.

Considering the convenience of use, the form of porous microcapsules encapsulating a photo-semiconductor is considered suitable. The porous microcapsules containing the above-mentioned photo-semiconductor will be described in detail below.

As the above-mentioned porous microcapsules, those obtained by a generally used method for preparing an oil-in-water type (O / W type) or a water-in-oil type (W / O type) emulsion can be used. I can. It is also possible to control the particle size and porosity of the powder by a known microcapsule forming method as disclosed in Japanese Patent Publication No. 54-6251. The porosity of the porous microcapsules encapsulating the photo-semiconductor of the present invention is not particularly limited, but if the photo-semiconductor is completely covered, the catalytic action is lowered.

When coming into contact with the skin, it is preferable that the photo-semiconductor is completely encapsulated. In order to completely encapsulate the photo-semiconductor, a microcapsule having a multi-layer structure can be prepared by a method of preparing a multi-phase emulsion of so-called (O / W) / O type or (W / O) / W type. I can. The microcapsules having a multilayer structure can be obtained by combining the known method as exemplified above and the method for preparing a multiphase emulsion.

The size of the porous microcapsules is not particularly limited, but the diameter (major axis) is 0.4 μm when transparency is imparted or coloring is not preferable.
m or less is preferable.

The material constituting the wall of the microcapsule containing the above-mentioned photo-semiconductor is a material which can be dissolved or dispersed in a solvent used for preparing an emulsion and can be cured. Among them, those that do not easily deteriorate even if they come into direct contact with the photo-semiconductor are selected. Materials that satisfy this condition include inorganic substances such as silica and alumina, and Teflon resin. More specifically, an emulsion is prepared using water glass and aluminum chloride, and after curing, microcapsules having silica and alumina walls can be obtained.

As a method of making the microcapsules porous, a method of preparing an emulsion using an inorganic material mixed with an organic substance and baking the organic substance alone after the formation of the microcapsules or dissolving it with a solvent is used. Examples thereof include a method in which a water-soluble or oil-soluble salt or the like is mixed and then this is dissolved.

If the amount of the photo-semiconductor contained in the microcapsules is too large, the photoconductive substance cannot be completely encapsulated and floats outside the microcapsules. If the amount is too small, the melanin pigment decomposing effect is not exhibited. An appropriate amount is 0.
It is from 01 to 70 parts by weight.

The conditions of the porous material covering the photo-semiconductor material and the method of making the material porous are the same as described above, except for the case of the microcapsules.

<Method of Utilization> As a method of utilizing the photo-semiconductor of the present invention, the objective substance is added directly to the material constituting the objective substance to which the melanin pigment decomposing function is added, and the objective substance is added to the coating composition. And the like. The amount of addition
For example, when the target is made of synthetic resin, it is preferably 1 to 1000 parts by weight with respect to 100 parts by weight of the synthetic resin. If it is 1 part by weight or less, the melanin pigment decomposing property is not sufficient, and if it exceeds 1000 parts by weight, the handling of the resin composition becomes difficult, or the surface condition of the finished product after processing, molding, etc. becomes poor. Or strength may decrease. More preferably, it is 10 to 500 parts by weight.

When the product of the present invention is used as a cosmetic material, it is preferable to coat it with a light semiconductive substance in order to avoid rough skin. The addition amount may be extremely small compared to the case of the above synthetic resin. In general, the same cosmetic material is used by repeatedly applying and cleaning the same material every day. Therefore, even if the amount of the photoconductive substance added is small, the purpose can be achieved by using it multiple times. Considering the possibility of causing skin irritation, efforts should be made to minimize the amount of melanin degrading.

[0025]

【Example】

Example 1 Titanium oxide (manufactured by Ishihara Sangyo Co., anatase type, particle size 7n
m) Powder was used.

Example 2 Titanium oxide (manufactured by Ishihara Sangyo Co., anatase type, particle size 7n
m) (50 g) was added to an aqueous solution of sodium silicate (4 mol / l in terms of silicon dioxide) (500 ml) and stirred for 10 minutes to prepare a uniform suspension. The above suspension was added to 1 l of a sorbitan monostearate solution in toluene (1% by weight), and the mixture was shaken for 5 minutes using a shaker to give a W / O type (water-in-oil type) emulsion. Was prepared. Next, the above emulsion was added to 4 l of an ammonium sulfate aqueous solution (1 mol / l) with stirring and reacted for 30 minutes. After completion of the reaction, the mixture was filtered, washed with water, and dried at 110 ° C. for 24 hours to obtain a spherical composite powder having titanium oxide inside and constituted by a wall made of silica and having an average particle diameter of 7 μm.

Example 3 Titanium oxide (manufactured by Ishihara Sangyo Kaisha, anatase type, particle size 7n
m) 9 parts by weight and 1 part by weight of antimony oxide-containing tin oxide (“T-1” manufactured by Mitsubishi Materials Corporation, particle size 0.02 μm) were mixed to use a powder.

Example 4 A wall made of silica having titanium oxide and tin oxide inside was prepared in the same manner as in Example 2 except that the titanium oxide / tin oxide mixed powder used in Example 3 was used. A spherical composite powder having an average particle size of 7 μm was obtained.

<Evaluation of Degradability of Melanin Pigment: Powder> 10 mg of melanin (manufactured by Nacalai Tesque, Inc.) was dissolved in 1 ml of dimethyl sulfoxide (DMSO), and 9 ml of water was further added to prepare a melanin solution. 5m of the above melanin solution
50 mg of the titanium oxide powder or the composite powder produced in Examples 1 to 4 was added to 1 l and shaken at 25 ° C., and after 2 hours and 18 hours, 1.0 ml of this solution was recovered. After the collected solution was centrifuged at 5000 rpm for 5 minutes, 0.5 ml of the supernatant was sampled and the absorbance at 475 nm was measured (10% by volume DMSO aqueous solution was used as a blank). For comparison, the same evaluation as above was performed without adding the titanium oxide powder or the composite powder to the melanin solution. The results are shown in Table 1. It was confirmed that although the melanin solution alone progressed in the formation of melanin, the melanin was decomposed in the examples in which titanium oxide was added.

[0030]

[Table 1]

<Preparation of test plate> Examples 1 to 4 above
10 parts by weight of the titanium oxide powder or the composite powder of 10% of unsaturated polyester (“V-262G” manufactured by Mitsui Toatsu Chemicals, Inc.)
It was mixed in 0 part by weight and dispersed for 4 hours using a disperser. Further, 4 parts by weight of methyl ethyl ketone peroxide (MEKP) 55% by weight dimethyl phthalate solution as a thermal polymerization initiator and 2 parts by weight of cobalt naphthenate (metal content 6% by weight) as a curing accelerator were added and mixed. This composition was applied to a FRP mold for trial production of a flat plate sample, which had been previously treated with a release agent, to a thickness of about 200 μm, and was once cured at 80 ° C. for 15 minutes. After cooling, a resin solution obtained by adding 55% by weight of MEKP dimethyl phthalate solution to the above unsaturated polyester resin and mixing it on the obtained coating was poured into a mold, and after curing, the mold was released from the FRP mold to form a melanin pigment decomposable resin layer. A test plate with was prepared.

<Evaluation of Degradability of Melanin Pigment: Test Plate> After dropping 5 ml of the melanin solution on the above test plate,
After standing for 2 hours at 25 ° C. and after 2 hours and 18 hours, 0.5 ml of this solution was collected and the absorbance at 475 nm was measured (10% by weight DMSO aqueous solution was used as a blank). For comparison, a plate containing no titanium oxide powder or composite powder was prepared and evaluated in the same manner as above. The results are shown in Table 1. It was confirmed that although the melanin solution alone progressed in the formation of melanin, the melanin was decomposed in the examples in which titanium oxide was added.

<Weather resistance> An accelerated weather resistance test was conducted using a test device using a sunshine carbon arc lamp specified in JIS-A1415, and the color difference of the plate after irradiation for 200 hours was measured by a color difference meter (Tokyo Denshoku Co., Ltd.). Manufactured by Color Analyzer TC-1800MK), and the absolute value of the color difference changed from before the test is shown. Further, the surface of the plate after the test was lightly rubbed with a finger to observe the presence or absence of chalking. ○ No chalking is observed × The results of the chalking are shown in Table 1. It was confirmed that Examples 2 and 4, which are porous microcapsules encapsulating titanium oxide, did not deteriorate as compared with Examples 1 and 3 in which titanium oxide was directly added. This indicates that when a photoconductive substance is added to a material such as an organic polymer such as unsaturated polyester used for the test plate, deterioration can be suppressed by encapsulation with porous microcapsules. .

[0034]

INDUSTRIAL APPLICABILITY The present invention provides a novel melanin pigment degrading substance by utilizing the property that a photoconductive substance acts on a melanin pigment possessed by microorganisms, plants, animals and the like to lower the molecular weight or decompose it. Using the melanin pigment-decomposing substance of the present invention,
It is possible to decolor mold stains adhering to the surfaces of walls, tiles, plastics, joints, etc. in houses and to remove stains, freckles, etc. generated on human skin. Furthermore, the effect of melanin pigment decomposition is improved by adding a small amount of conductive powder. In addition, by using the light semiconducting substance coated with a porous substance, deterioration due to contact between the light semiconducting substance and the constituent components of the substrate is avoided, and the substrate constitution is not limited by the above deterioration. Since the components can be selected, it is advantageous in various usage forms.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B01J 35/02 B01J 35/02 J

Claims (4)

[Claims] 1. A melanin pigment decomposing substance comprising a photo-semiconductive substance. 2. A melanin pigment decomposing substance comprising a photo-semiconductive substance and a conductive substance. 3. The melanin pigment decomposing substance according to claim 1, wherein the photo-semiconductor substance is coated with a porous substance. 4. The melanin pigment-decomposing substance according to claim 1, wherein the photo-semiconductor is titanium dioxide.