JPH1129760A - Ultraviolet protecting agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ultraviolet protecting agent at a low cost from a clay mineral by forming an ion-exchanging clay/calcium silicate composite or by intercalating a metal ion between layers of calcium silicate. SOLUTION: A smectite clay mineral contg. amorphous silicic acid (e.g. a kaolin mineral or a smectite mineral) can be used as the material for a clay/ calcium silicate composite. The ion-exchanging claw/calcium silicate composite is obtd. by reacting clay mineral particles, such as of smectite clay, with a calcium compd. A pref. calcium compd. is calcium oxide or hydroxide. For example, acid clay contg. amorphous silica is reacted with lime as shown by the formula to form calcium silicate. A salt of a metal, pref. selected from among metals of the iron group and the aluminum group, is used for the intercalation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an ultraviolet ray protective agent obtained from an ion exchanger using clay minerals as a raw material.

[0002]

2. Description of the Related Art Ultraviolet rays have an adverse effect on human skin, such as causing suntan, sunburn, photosensitive dermatitis, promoting skin aging, and causing skin cancer. In recent years, this has been widely recognized, and attempts have been made to impart an ultraviolet ray preventing function to various things such as cosmetics and clothing. For example, in the case of cosmetics, an ultraviolet ray preventing effect is imparted by blending an inorganic ultraviolet ray scattering agent composed of fine particles of titanium oxide or an organic ultraviolet ray absorbent composed of a phenolic substance having a conjugated double bond. However, inorganic ultraviolet scattering agents have problems such as deterioration of usability due to fine particles, reaggregation of dispersed fine particles, and decrease in light resistance due to photocatalytic activity. In the case of an organic ultraviolet absorber, there is a problem that the amount that can be prescribed is limited. Further, organic UV protective agents are often used by dissolving them in an oily solvent, and their uses are limited. For this reason, there has been a demand for the development of a novel ultraviolet ray protective agent which has an excellent ultraviolet ray preventing effect, is chemically stable, and is not easily restricted by its formulation by being mixed with various kinds and forms of materials. On the other hand, Japanese Patent Application Laid-Open No.
No. 0256 discloses a layered silicate mineral in which metal ions are intercalated between layers, and describes that it has an ultraviolet protection function. When this layered silicate mineral powder is obtained from a clay raw material, it is usually necessary to separate only fine clay particles having ion exchange ability by elutriation. However, when using natural mineral resources as raw materials,
The content of clay particles is usually 70% or less. Furthermore, since only fine particles are collected by elutriation, the powder that can be used as a raw material has a low yield, and the elutriated residue is discarded and wasted. Further, since the production cost increases after the elutriation step, the development of a less expensive ultraviolet ray protective agent has been desired.

[0003]

Accordingly, the present invention provides
It is an object of the present invention to provide an inexpensive ultraviolet ray protective agent using clay mineral as a raw material without performing elutriation operation.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, it has been found that a clay raw material is made into a complex with calcium silicate to impart ion exchangeability. It was found that intercalation of a metal ion between the layers of this compound causes an ultraviolet blocking effect, and based on this finding, the present invention has been accomplished. That is, the present invention provides (1) an ultraviolet ray protective agent characterized in that a metal ion is intercalated between layers of an ion-exchangeable clay-calcium silicate composite or calcium silicate; (1) the ultraviolet ray protective agent according to item (1), which is a metal selected from iron group, aluminum group, titanium group, zinc group, copper group, alkaline earth metal or chromium group; The ultraviolet ray protective agent according to item (1), which is nickel, zirconium, zinc, copper, barium or titanium, (4)
The ultraviolet protective agent according to (1), (2) or (3), wherein the ion-exchangeable clay-calcium silicate composite is obtained by reacting a calcium compound with a clay containing reactive silica. And (5) the ultraviolet-protecting agent according to (1), (2), (3) or (4), wherein the ion-exchangeable calcium silicate is obtained by reacting silica with a calcium compound. It is. In the present invention, the term "ion-exchange property" refers to a property capable of performing an ion-exchange reaction and a property capable of intercalating metal ions between layers.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The clay used as a raw material of the ion-exchangeable clay-calcium silicate composite used in the present invention is, for example, a smectite-based clay such as a kaolin-group mineral or a smectite-group mineral, which is an amorphous silica. Minerals containing acids can be used. Amorphous silicic acid is formed by changing part of smectite due to weathering of clay. Smectite clay consists of a combination of a tetrahedral sheet in which a silica-oxygen tetrahedron is continuous two-dimensionally in a network and an octahedral sheet in which an octahedron such as aluminum-oxygen is continuous in a net-like manner. Can be taken. The surface of the layer has the property of adsorbing cations because it has a negative charge, but the cations that have entered the layer have weaker bonds than ionic bonds and can be freely exchanged with other cations. For this reason, various ion exchange reactions can be performed on the layer surface.

The smectite clay is roughly classified into four types depending on the degree of weathering: sodium bentonite, calcium bentonite, B-type acid clay, and A-type acid clay. Among them, the most weathered A-type acid clay is abundant throughout Japan, but has little use. Activated clay with high adsorptivity and many uses can be produced only in a small part of Niigata and Yamagata prefectures. Is almost unused. The clay-calcium silicate composite used in the present invention can also be obtained using this A-type acid clay.

The ion-exchangeable clay used in the present invention
The calcium silicate complex can be obtained by reacting a clay compound with the above-described smectite-based clay or other clay mineral particles and a calcium compound. As calcium compounds,
For example, calcium oxide, calcium hydroxide, calcium chloride, calcium nitrate and the like can be mentioned. From the viewpoint of cost, calcium oxide and calcium hydroxide are preferably used. For example, when acid clay containing amorphous silica and lime are reacted, it is considered that calcium silicate is generated as described below.

[0008]

Embedded image

Usually, a calcium compound is reacted with a clay mineral in an aqueous solution at normal pressure or under pressure. The amount of the calcium compound is preferably 10 to 60% by weight, more preferably 20 to 50% by weight in terms of CaO, based on the total amount of the clay mineral and the calcium compound. If the amount of the calcium compound is too small, the formation of calcium silicate may be insufficient, and the silica compound may remain and the adsorption characteristics may not be improved. If the calcium compound is too large, unreacted calcium compound remains as it is and the particles grow,
Again, it may not be suitable for use in the ultraviolet protection agent of the present invention. Further, when calcium chloride is used, sodium carbonate is preferably added, and when calcium nitrate is used, sodium hydroxide is preferably added in an amount of 1 to 5% by weight based on the total amount of the clay mineral and the calcium compound. As for the amount of water used, the liquid / solid ratio (weight ratio, hereinafter the same) is preferably 10 to 30. Complexing is usually carried out at 80 to 250 ° C, preferably 90 to 200 ° C for 1 to 24 hours, preferably 5 to 1 hour.
Obtained by stirring the above proportions of clay and calcium compound with water for 0 hours. It is carried out under normal pressure or under pressure, preferably at normal pressure to 10 kgf / cm ² .

In the reaction between a clay and a calcium compound, the type of starting materials and the reaction conditions affect the structure and properties of the resulting composite. For example, in acid clay, sodium bentonite is acidified by weathering and interlayer ions of clay particles are replaced by H ⁺ and Ca ²⁺ , but the smectite mineral in the raw ore is partially amorphous silica by weathering. Has been replaced by This amorphous silica easily reacts with an alkaline earth metal compound and easily reacts with lime or the like to form a silicate. Clay minerals-silicates can be synthesized in the same way with other clay minerals containing other silica compounds.However, silica compounds in minerals that have not progressed to weathering contain less reactive amorphous silica, Since there are many such substances, it is necessary to carry out a hydrothermal reaction for a long time or to promote the reaction at a high pressure. When the proportion of amorphous silica is high, the composite obtained has a high ion-exchange property, and a composite using clay in which amorphous silica is 10% or more of the silica compound (clay-
Low crystalline calcium silicate complex) is preferred. At this time, it is naturally possible to use acid clay or the like having little amorphous silicic acid after acid treatment. Alternatively, a tobermorite-clay composite in which calcium silicate particles are grown can be used as the ion-exchange composite. In the synthesis of the tobermorite-clay composite, a clay with a large amount of crystalline silica that has not progressed to weathering can also be used, and further promotes a hydrothermal reaction in addition to the above-described complexation reaction, and reduces the calcium silicate particles. Grow and manufacture.

On the other hand, calcium silicate also has ion exchange properties as one of the inorganic ion exchangers. These are a basic unit layer in which a single chain of SiO ₄ tetrahedron sandwiches a sheet of Ca—O in a sandwich shape, and Ca ²⁺ ions or H 2
_{It is} a kind of layered mineral compound containing ₂ O molecules, and can perform various ion exchange reactions like clay particles.

[0012] The calcium silicate used in the present invention can be obtained by reacting silica with a calcium compound.
Silica is preferably amorphous silica, and a product obtained by purifying a natural mineral raw material or a commercially available product can be used without any particular limitation. As the calcium compound, the same ones as mentioned in the production of the composite can be used, and the amount of silica and calcium compound used is usually 0.44 to 3 in terms of SiO ₂ and CaO (CaO / SiO ₂ (weight)). .0,
Preferably it is 0.5-1.7. Furthermore, Al / Si
(Weight) is 0.01 to 0.13, preferably 0.05 to
It is preferable to use an aluminum compound so as to be 0.10. As the aluminum compound, for example, aluminum hydroxide, aluminum oxide, or the like can be used. These raw materials are slurried with water in a liquid / solid ratio of usually 10 to 30, preferably 15 to 25, usually at 70 to 100 ° C, preferably 5 to 10 at 80 to 95 ° C.
After stirring for an hour, using an autoclave, usually 100 to 100
250 ° C, preferably normal pressure to 15k at 100 to 180 ° C
gf / cm ² , preferably at normal pressure to 10 kgf / cm ² for 5 to 10 hours, followed by drying.

The above-mentioned complex or calcium silicate used in the present invention focuses on amorphous silica formed by decomposition of a clay mineral, and has an adsorptive property and a filtering function by secondary acid treatment or complex formation. Is given.

In the present invention, the intercalation
Metal salts, preferably iron group such as iron or nickel, aluminum group such as aluminum, titanium group such as titanium or zirconium, zinc group such as zinc, homologous group such as copper, alkaline earth metal such as barium or chromium such as tungsten It can be performed using a metal salt of a metal selected from the genus. Examples of such metal salts include iron chloride, aluminum chloride, nickel chloride, zirconium chloride, zinc chloride, copper chloride, barium chloride, titanium chloride and the like. Water is added to the above-mentioned clay-calcium silicate composite or calcium silicate, and for example, a metal chloride or the like is added and stirred, and intercalation is performed by a usual method. Next, the liquid is filtered to separate a solid content, which is dried and, if necessary, crushed to obtain a desired ultraviolet protective agent. The amount of the metal salt added is determined by the cation exchange capacity of the clay-calcium silicate complex or calcium silicate, and is often 2 to 100 parts by weight of the clay-calcium silicate complex and / or calcium silicate. It is more than 3 parts by weight, preferably 3 to 20 parts by weight, but is not limited thereto. The intercalation reaction is carried out so that the cation exchange rate of the clay-calcium silicate complex and / or calcium silicate is preferably at least 85%, particularly preferably at least 90%. During the intercalation, the pH of the solution is preferably 10 or less, and the temperature is usually room temperature. The ultraviolet protective agent in which the metal ions are intercalated is used as a dry powder or dispersed in a predetermined amount of an aqueous medium.

[0015]

Next, the present invention will be described in more detail with reference to examples. In addition, the ratio in an Example is a weight ratio, and the usage-amount (weight%) of each metal salt is a ratio with respect to a clay-calcium silicate composite or calcium silicate. Example 1 An acid clay (manufactured by Kunimine Industry Co., Ltd.) was treated with a ball mill for 24
The mixture is pulverized for a period of time, and calcium chloride or calcium nitrate is used as a calcium compound.
O = 70: 30, water was added so that the liquid / solid ratio became 20, and a slurry was obtained.
Heated. When calcium chloride was used, sodium carbonate was added, and when calcium nitrate was used, sodium hydroxide was added at 1 to 5% by weight. The slurry was filtered, washed with water, and dried to obtain a clay-calcium silicate composite.
From the X-ray diffraction results of the composite, cristobalite and α-
The peak of a silica compound such as quartz disappears, and low-crystalline calcium silicate (Calcium-Silicate-H
ydrate: CSH) was confirmed to be produced. The ion exchange capacity of this complex is 90 meq / 1.
00 g. 3 kg of the obtained clay-calcium silicate complex was put into a 5 liter beaker together with 5 liters of water, and 6.3 g of iron chloride was added while stirring with a stirrer. Next, the mixture was placed in a Buchner funnel and filtered by suction.
It was dried at 05 ± 5 ° C. and pulverized to obtain an ultraviolet protective agent (particle size: 10 μm) in which iron ions were intercalated between layers. The ion exchange rate with iron chloride was 99.5%.

Example 2 The procedure of Example 1 was repeated, except that 7.6% by weight of nickel chloride was added instead of iron chloride.
m, ion exchange rate 99.2%).

Example 3 The procedure of Example 1 was repeated, except that 7.0% by weight of cobalt chloride was added instead of iron chloride.
m, ion exchange rate 98.4%).

Example 4 Silicon dioxide (amorphous silicic acid, manufactured by Kanto Chemical Co., Ltd.) as silica, aluminum hydroxide (manufactured by Kanto Chemical Co., Ltd.) as an aluminum compound, lime as a calcium compound, C
aO / SiO ₂ = 20 and Al / Si = 0.05, and water was added so as to have a liquid / solid ratio of 10 to form a slurry. The mixture was stirred at 90 ° C. for 5 hours, and then autoclaved. The mixture was treated at 180 ° C. under a pressure of 10 kgf / cm ² for 24 hours to synthesize calcium silicate. The ion exchange capacity of this calcium silicate was 60 meq / 100 g. Water and 7.6% by weight of nickel chloride were added thereto, and nickel ions were intercalated in the same manner as in Example 1 to give an ultraviolet ray protective agent (particle size: 30 μm, ion exchange rate: 8
9.0%).

The ultraviolet protective agent obtained in Examples 1 to 4 was used as a suspension having a concentration of 0.125%.
0 nm) was measured with a self-recording spectrophotometer U-3200 (manufactured by Hitachi, Ltd.). For comparison, the ultraviolet transmittance was similarly measured for an untreated acid clay powder (particle size: 30 μm). Table 1 shows the results.

[0020]

[Table 1]

As shown in Table 1, by reacting with a calcium compound to form a complex and intercalating a metal ion between the layers, the acid clay particles which had a low ultraviolet protection effect and could not be used as an ultraviolet protection agent were remarkably blocked by ultraviolet rays. It can be seen that the effect has occurred. In addition, the results of Example 4 show that even when metal ions are intercalated into calcium silicate, an ultraviolet protective agent having the same effect as that obtained by using the clay-calcium silicate composite is obtained.

[0022]

As is clear from the above results, the ultraviolet protective agent of the present invention is excellent in the effect of blocking ultraviolet rays,
It has excellent dispersion stability and is chemically stable and hardly deteriorates. The ion-exchangeable complex or calcium silicate used for the ultraviolet ray protective agent of the present invention can be obtained without using an elutriation step even using a clay raw material produced and used in various parts of Japan, and the residue is discarded. A UV protection agent can be provided at low cost without generating any. This UV protection agent can be used for various uses such as cosmetics, resins, paints, and fibers.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Mikuni 3045-19 Yoshida, Yamaguchi, Yamaguchi Prefecture (72) Inventor, Kiyoji Miyoshi 1163-3 Asada, Yamaguchi, Yamaguchi 1182-3 Higashisue (72) Inventor Masahiro Maeno 4-8-39 Higashi Kobayama, Ube City, Yamaguchi Prefecture (72) Inventor Touhou Kuwahara 4-821 Miharacho, Kuroiso City, Tochigi Prefecture

Claims (5)

[Claims] 1. An ultraviolet protective agent comprising a metal ion intercalated between layers of an ion-exchangeable clay-calcium silicate composite or calcium silicate. 2. The ultraviolet protective agent according to claim 1, wherein the metal ion is a metal selected from iron group, aluminum group, titanium group, zinc group, copper group, alkaline earth metal and chromium group. 3. The ultraviolet protective agent according to claim 1, wherein the metal ion is iron, aluminum, nickel, zirconium, zinc, copper, barium or titanium. 4. The ion-exchangeable clay-calcium silicate composite is obtained by reacting a calcium compound with a reactive clay containing silica.
The ultraviolet protective agent according to the above. 5. The ultraviolet protective agent according to claim 1, wherein the ion-exchangeable calcium silicate is obtained by reacting silica with a calcium compound.