JPH0234589A - Selective light transmitting powder material - Google Patents

Abstract

PURPOSE:To obtain a powdery material capable of isolating ultraviolet rays and infrared rays and transmitting visible rays by forming a selective light transmitting film on the surface of transparent mica. CONSTITUTION:A selective light transmitting film is formed on the surface of transparent mica such as muscovite. Preferred selective light transmitting film is one comprising (A) three layers of a transparent oxide having high refractive index, thin metallic film, and a transparent oxide having high refractive index, laminated successively in the described order, (B) two layers of a transparent oxide having high refractive index and a thin metallic film, laminated successively in the described order, or (C) two layers of a thin metallic film and a transparent oxide having high refractive index laminated in the described order, on the surface of mica. Suitable thin metallic film is a thin film of Au, Ag, Cu, Pd, etc., or an alloy thereof prepd. by sputtering and having 50-250Angstrom thickness, and suitable transparent oxide having high refractive index is thin film of TiO2, BaS, Ba titanate, etc., prepd. by sputtering and having 100-600Angstrom thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a powder material having selective light transmittance using mica.

[Prior Art] Mica is a naturally produced mineral and is generally a transparent substance. Furthermore, as will be described later, mica is a layered material consisting of regular tetrahedrons, so it has the characteristic that it can be easily formed into a thin film in the C-axis direction. Therefore, this crushed material can be used for cosmetics,
It is used to add a pearlescent tone to paints, etc.

Furthermore, in recent years, mica whose surface is coated with a thin film of a metal oxide having a high refractive index such as Ti0z (titanium dioxide) has been proposed. This material has the effect of transmitting visible light and infrared light and cutting off ultraviolet light. Therefore, this product can be incorporated into cosmetics and used as a sunscreen cream.

[Problem to be solved]

However, it is not limited to sun protection cream.

In transparent resins, sunglasses, automobile paints, etc., there is a desire to block infrared light as well as ultraviolet light.

In view of such conventional problems, the present invention focuses on the use of mica having the above-mentioned characteristics, and has a selective light transmittance that allows visible light to pass through but infrared light and ultraviolet light to be blocked. The aim is to provide powder materials.

[Means for solving problems]

The present invention resides in a selective light transmitting powder material, which is a powder material formed by forming a selective light transmitting film on the surface of transparent mica.

The mica used in the present invention has a visible light transmittance of 90% or more. It is preferable to use a transparent mica, and mica has the following types and characteristics. That is, the most common type of mica is (AlSi3
0. . ) has a composition of 5-.

Muscovite is one in which 1/4 of this Si is replaced with AP. This muscovite has a unit of 5iO = /10. It has been replaced with a tetrahedron.

Al
are connected by + ions, and AN” itself uses OH- ions to complete the entrance position. Therefore, CAlz
CAl5 Is O+. )(OH) Two layers are stacked alternately with the composition:

An appropriate number of + ions are inserted in between to maintain electrical neutrality.

All micas are monoclinic and have a hexagonal plate shape with a completely cleaved base. Muscovite and phlogopite are colorless or light-colored, and biotite is dark-colored, and mica has strong birefringence and exhibits pearly or metallic luster.

The reason why the above-mentioned cleavage property is remarkable in mica is that the bonding along the + ion layer is weak.

On the other hand, A2, which plays the role of binding JW, is Mg.

K between the sand inches tends to be replaced with Na, and various similar structures are easily formed. For this reason, in addition to muscovite, biotite K (Mg, Fe)s (AI!, 5iso
lo) ・ (OH)! , phlogopite K M g s
(A l Si0+.).(OH)t, iron mica, soda mica, *mica, Chinwald mica, etc. also exist.

Next, as a selective light transmission film to be formed on the surface of mica,
It allows visible light to pass through, but hardly any infrared light or ultraviolet light. Use a membrane.

As such a selective light transmitting film, for example, a laminate in which one or both sides of a metal thin film is coated with a transparent high refractive index oxide is used.

That is, a selective light transmission film consisting of three layers in the order of a transparent high refractive index oxide, a metal thin film, and a transparent high refractive index oxide on the surface of mica, or a transparent high refractive index oxide and a metal thin film on the mica surface in this order. or a metal thin film and a transparent high refractive index oxide in this order. Further, the selective light transmission film is formed on one or both sides of the mica. These are then ground into powder and added to cosmetics, etc., as described below.

The metal thin film is gold, which has a small absorption loss in the visible light region, 1 m, w4. Palladium and alloys thereof are preferred, and the thickness of the metal thin film is not particularly limited as long as it satisfies the requirements as a selective light transmitting film.
If transparency is to be utilized, the thickness is preferably 250 Å or less, and the lower limit is preferably 50 λ or more, which can form a continuous film.

Vacuum deposition is a method for forming a metal thin film layer.

Dry plating methods such as sputtering are suitable.

Sputtering is most suitable for forming a transparent high refractive index oxide on the metal thin film.

This metal thin film is formed on the transparent high refractive index oxide formed on the mica surface or on the mica surface.

The transparent high refractive index oxide provided on one or both sides of the metal thin film has a refractive index of 1.8 or more for visible light.

It preferably has a visible light transmittance of 2.0 or more and a visible light transmittance of 80% or more, preferably 90% or more.

The film thickness may be any thickness as long as a desired selective light transmitting film can be obtained, but it is usually 100 to 600, preferably 150 to 400. Examples of materials that meet these conditions include titanium oxide, zinc sulfide, and barium titanate.

The method for forming the transparent high refractive index oxide is also the same as the method for forming the metal thin film, and sputtering is preferred.

Thus, the mica on which the selective light transmitting film has been formed as described above is ground into a powder to obtain a powder material according to the present invention. This powder material may be in the form of small pieces or scales,
Preferably, the diameter is 1 μm to 5 mm and the thickness is 1 to 100 μm. If the diameter is less than 1 μm, the selective light transmitting film formed on the mica will easily peel off, while if it exceeds 5 mm, it will be difficult to add it to resins etc. as a powder, especially for cosmetics. When added to a paint, it is preferably a powder material with a diameter of 100 μm or less.

The powder material of the present invention is suitable for cosmetics, resins, and glass.

Used by mixing with various paints, etc.

[Action and effect]

The selective light transmitting powder material of the present invention is formed by forming a selective light transmitting film on the surface of mica. And mica has transparency,
It is also a material with high birefringence.

Therefore, due to the birefringence of mica and the visible light selectivity of the two-selective light transmitting film, it has pearlescent properties and can transmit visible light but block infrared and ultraviolet light. A transparent powder material can be provided.

However, since this product is in powder form, it is especially useful for cosmetics,
When added to paints, it is uniformly dispersed within the paint and functions as a fine selective light-transmitting substance.

Additionally, since the base material is mica, which is an inorganic material, it has excellent heat resistance. Furthermore, it is possible to use mica as a base material, which is a natural product, and is inexpensive. Furthermore, when muscovite is used as the mica, since muscovite has a large birefringence, it exhibits very excellent selective light transmittance.

〔Example〕

As shown in FIG. 2, a selective light transmitting film 2 is formed on one surface of mica 1 as a base material, and then this is crushed to form a first
A selective light transmitting powder material according to the present invention as shown in the figure was prepared.

The selective light transmitting film 2 includes a Ti0z film 21 as a transparent high refractive index oxide on the surface of the mica 1. On top of that is an Ag film 22 as a metal thin film. Furthermore, a TiCh film 21 as a transparent high refractive index oxide is formed on the top surface.

As the mica 1, flaky muscovite having a size of 30×50 m and a thickness of 50 μm was used. Next, the surface of the mica base coat film was degreased with isopropyl alcohol, and then the substrate was etched in an argon (Ar) gas atmosphere of 7×10-'Torr. The output at this time is 15
The etching time was 20 minutes at 0W.

Next, in forming the selective light transmitting film 2, a Tie and a target (purity 99.99%) metal-bonded to a copper plate were first used to form a TiOz film 21 as a transparent high refractive index oxide as a lower layer. R using high frequency
RF output 600W with F magnetron sputtering equipment,
#21 as a transparent high refractive index oxide was formed on mica at an Ar pressure of 7×10''' Torr.

Next, an Ag target (99,99%) was used to form the Ag film 22 as a metal thin film, and 100 people were exposed to A as a metal thin film at a DC (direct current) output of 0.5A x 550V.
A g film 22 was formed. after that.

Furthermore, in order to form a transparent high refractive index oxide as the uppermost layer, an upper layer of T is formed on the Ag film 22 under the same conditions as the lower layer Tie and film 21.
300 people formed i Oz M 21.

As a result of the above, a two-selective light-transmitting film-forming mica lO was obtained (FIG. 2).

Next, the selective light transmission film-forming mica 10 was pulverized using a pulverizer. As a result, as shown in FIG. 1, the selective light transmitting film 2 is provided on the surface of the mica 1. Diameter 30~
A selectively transparent powder material 15 of 500 um was obtained.

The light transmittance of the selective light transmission film-forming mica 10 (sample 1) was measured in the wavelength range of 300 to 2500 nm. The result.

Figure 3 shows the wavelength (nm) on the horizontal axis and the light transmittance (%) on the vertical axis.
As shown in the figure,

It can be seen that the product of the present invention exhibits a transmittance of 70% or more in the visible light region, but the transmittance of infrared light and ultraviolet light is extremely low.

In addition, a sample No. 2 was prepared in which a selective light transmitting film similar to that on one side of the mica 1 was formed on both sides of the mica 1. The measurement results are also shown in the figure. It can be seen that the sample Nα2 has a greater ability to block infrared light and ultraviolet light than the case of Nα1.

In addition, for comparison, measurements were also made on only muscovite without a selective light transmission film formed thereon. As a result, as shown in the same figure, it is found that the material exhibits high light transmittance in both visible light and infrared light regions, and does not have selective light transmittance.

[Brief explanation of the drawing]

The figures show examples, and FIG. 1 is a perspective view of a selective light transmitting powder material, and FIG. 2 is an explanatory cross-sectional view of mica forming a selective light transmitting film.9 FIG. 3 is a light transmittance of the selective light transmitting powder material. FIG. 1゜15゜2゜21゜22゜mica. Selective light transmitting powder material ゛Selective light transmitting film. TiO□ film. Ag film. Applicant: Toyoda Gosei Co., Ltd. Toyota Central Research Laboratory Co., Ltd.

Claims (1)

[Claims] A selective light transmitting powder material, characterized in that it is a powder material formed by forming a selective light transmitting film on the surface of transparent mica.