JPH0621025B2 - Synthetic mica - Google Patents

Description

TECHNICAL FIELD The present invention relates to a synthetic mica, particularly a synthetic mica having a high degree of whiteness, which can be incorporated into cosmetics, paints or plastics to obtain an ultraviolet absorbing effect.

[Conventional technology]

As one of the conventional UV absorbers, benzophenone-based,
Organic compounds such as bezotriazole, salicylate, and acrylonitrile have been added to plastics and cosmetics. However, all of the above-mentioned ultraviolet absorbers are easily decomposed by ultraviolet rays, so that not only the effect does not last, but also cosmetics may cause an allergic reaction to the skin, which is inconvenient.

Further, as JP-A-58-19379, an artificial mica containing one or more of nickel, cobalt, manganese, titanium, vanadium and barium as a main component is used.
An ultraviolet absorber having both visible light transmittance and ultraviolet absorption has been proposed.

Further, the inventors have proposed "ultraviolet absorbing flake glass" as Japanese Patent Laid-Open No. 63-307142.

[Problems to be Solved by the Invention] Among the artificial mica of JP-A-58-19379, the artificial mica containing nickel, cobalt, and manganese has a higher absorption coefficient in the visible region than in the ultraviolet region. Since it is several tens of times higher, it is difficult to obtain the target artificial mica with high whiteness, and the artificial mica containing titanium and barium has an extremely small absorption coefficient in both the ultraviolet and visible regions, which makes it difficult to absorb ultraviolet light. There is a disadvantage that it is difficult to obtain the artificial mica. Further, those containing vanadium have a high absorption in the ultraviolet region and a low absorption in the visible region, but vanadium pentoxide is toxic, so that it seems to cause a problem during production and use.

Further, the above-mentioned flake-shaped glass of JP-A-63-307142 is a material close to ideal because it has a high absorption in the ultraviolet region and a low absorption in the visible region, but it is produced when the flake thickness is 1 micron or less. There was an inconvenience that the property was low.

An object of the present invention is to solve the above-mentioned inconveniences in conventional ultraviolet absorbers.

That is, it is an object of the present invention to provide a synthetic mica which has high weather resistance, is harmless to the human body, has a sufficient whiteness and an ultraviolet absorbing effect, and has high productivity.

[Means for solving problems]

The gist of the present invention is represented by the general formula (1): Ce _{x KY} Mg ₃ Fe _Z Al _1-2 Si ₃ O ₁₀ F ₂ (wherein X, Y, and Z are 0.05 ≦ X ≦ 0.25. , 0.
25 ≦ Y ≦ 0.85, 0.10 ≦ Z ≦ 1.00) selected from the range)) is a synthetic mica.

[Action]

Ce has the function of oxidizing FeO into Fe203 in the melt in which synthetic mica precipitates. In a synthetic mica containing iron, the coloring of the synthetic mica is caused by FeO.
e has the effect of lowering the FeO content in the synthetic mica and increasing the whiteness of the synthetic mica. Further, Ce is an ultraviolet absorbing component together with Fe. In the general formula (1), X is 0.05
When it is less than the above, the effect of whitening of the synthetic mica is small, and when X exceeds 0.25, the synthetic mica is not generated.

K enters between layers composed of Mg3 (FeZA1-ZSi3O10F2). In the general formula (1), Y
Is less than 0.25, synthetic mica is not generated. Since Ce enters the same position as K, if Y exceeds 0.85, the Ce content cannot be increased and the whitening effect of Ce is lost.

Mg enters between the layers formed by (FeZAl1-ZSi3O10F2) and between the layers.

Fe forms a layered structure that forms a skeleton together with Al, Si, O, and F, and is an ultraviolet absorbing component. Since Fe is replaced by Al, the upper limit of Z in general formula (1) is 1.0
It is 0. When Z is less than 0.10, the effect of absorbing ultraviolet rays is small.

The synthetic mica according to the present invention is convenient for admixing it with cosmetics, paints or plastics to absorb ultraviolet rays. For that reason, flake-like fine particles having a thickness of 1 micron or less and a length of 50 micron or less are preferable. More preferably, it is flake-shaped fine particles having a thickness of 1 micron or less and a length of 5 micron or less.

〔Example〕

As raw materials, CeO2, K2SiF6, MgO, MgF
A batch was prepared by using 2, Fe2O3, Al2O3, and SiO2 so as to have the chemical composition shown in Table 1. At this time, F
Volatilizes, so the amount was adjusted to 1.5 times the required amount. Approximately 1 kilogram of the formulation was loaded into a platinum crucible and
It was melted in an electric furnace at 50 ° C. for 2 hours. Set the temperature of the electric furnace to 14
Crystallization was carried out by rapidly lowering the temperature to 00 ° C and then cooling to 950 ° C at a rate of 9 ° C per hour. The obtained crystallized product was pulverized with a vibration mill to obtain fine particles. Observation of the shape with an electron microscope revealed that the fine particles had a thickness of 1 micron or less and a length of 5 micron or less. In the BET method using nitrogen adsorption, the average particle size was 3 microns.

The characteristics of the fine particles are shown in Table 1. Table 1 also shows the characteristics of synthetic mica outside the scope of the present invention as a comparative example.

As for whiteness, the powder is put on a white transparent slide glass as a binder (TOSHIBA SPB-10FP: main component CH3COOC4H
9) was added and coated, dried and measured through glass.

The ultraviolet transmittance of the fine powder sample has a large light scattering effect, and it is difficult to obtain an accurate value even when the fine powder sample is dispersed and measured in various media. Here, 32 of Fe2O3 and CeO2 in soda, lime glass,
The optical absorption coefficient at 0 nanometer was 11.
43, the value estimated as 21.08 was shown.

The whiteness of the synthetic mica of the present invention is higher than that of the comparative example,
The low UV transmittance is apparent from Table 1.

〔The invention's effect〕

As described above, the artificial mica of the present invention has a high degree of whiteness, but can be used as a mixture with cosmetics, plastics, coating films, etc. for the purpose of remarkably preventing ultraviolet rays in a very thin thickness.

Claims (1)

[Claims] 1. A general _{formula: Ce X K Y Mg 3 Fe} Z Al 1-Z Si 3 O 1θ F 2
(1) (In the formula, X, Y, and Z are 0.05 ≦ X ≦ 0.25, 0.
25 ≦ Y ≦ 0.85, selected from the range of 0.10 ≦ Z ≦ 1.00)).