JPH0476083A - Ultraviolet-screening film - Google Patents

Abstract

PURPOSE:To obtain the title film having sufficient ability to transmit visible light and excellent in the ability to screen ultraviolet rays in the region near the visible light region by incorporating a specified metal oxide into cerium oxide. CONSTITUTION:An ultraviolet-screening film made of a compound oxide consisting of cerium oxide and an oxide of a metal having a valence higher than that of cerium, with the content of this metal oxide being 5-50wt.%. It can sufficiently screen ultraviolet rays of a wavelength of 380nm or shorter and sufficiently transmit visible light of a wavelength in the range from 380-780nm. Since it is obtained as a film, not a powder, it is not necessary to care about, e.g. the particle diameter of a product; further, when it is used as ultraviolet-screening material, it is not necessary to pay attention to, e.g. dispersion in a dispersant.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an ultraviolet shielding film made of an oxide mainly composed of cerium oxide, and more specifically, it has sufficient visible light transparency and ultraviolet ray shielding film. The present invention relates to an ultraviolet shielding film that has excellent ultraviolet shielding ability in a region close to the visible light region.

[Prior art and its problems]

Conventionally, polymer materials used in automobile interior parts are required to have very strong weather resistance such as ultraviolet resistance because they are exposed to sunlight for long periods of time. However, this polymeric material is generally sensitive to UV rays, so it is desirable to add UV shielding properties to the material or to prevent the effects of UV rays before the material is exposed to sunlight. There is.

In the former case, the application of the polymer material may be affected, such as the need to use a polymer material with excellent ultraviolet shielding ability or to coat the polymer material with a functional material that has excellent ultraviolet shielding ability. will be restricted.

In the latter case, the range of application of polymeric materials can be expanded by, for example, attaching a UV-shielding film to window glass or a sky roof to block UV rays before the interior components are irradiated with the light. I can do it.

There are various substances such as organic substances and inorganic substances that have ultraviolet shielding ability, and materials having ultraviolet shielding ability using these substances are actively being developed. However, when applying this to automobile window glass, sky roofs, etc., organic substances do not have a sufficient ultraviolet shielding effect, and there are many restrictions in terms of weather resistance, making it difficult to meet these requirements. I'm not satisfied with that.

On the other hand, an example of using an inorganic material is an "optical functional element" in which the substrate surface is coated with titanium oxide, cerium oxide, etc. to improve the wettability and ultraviolet shielding properties of the substrate surface (Japanese Patent Laid-Open No. 104028/1983). ) has been proposed. However, although this optical functional element has an excellent ability to block ultraviolet rays in the wavelength range of 360 nm or less, it has an insufficient ability to block ultraviolet rays in the wavelength range of 360 to 380 nm, which is close to the visible light range. was there.

[Purpose of the invention]

An object of the present invention is to provide an ultraviolet shielding film that has the property of sufficiently blocking ultraviolet rays having a wavelength of 380 nm or less and sufficiently transmitting visible light having a wavelength of 380 to 780 nm.

The present inventors have focused on the following regarding the problems of the prior art described above. That is, first, we focused on the light transmittance characteristics of cerium oxide, which is a material that has excellent ultraviolet shielding ability and excellent weather resistance. However, although this cerium oxide has excellent light transmittance in the visible light range of wavelengths from 380 nm to 780 nm and excellent UV shielding ability in the wavelength range of 360 nm or less, it UV shielding ability in the ultraviolet region is low. Therefore, in order to improve the ability to shield ultraviolet light in the ultraviolet region close to visible light, we focused on adding a second oxide.

Then, we focused on a composite oxide with a metal whose valence is higher than that of cerium, and created a UV-shielding film using a composite material consisting of cerium oxide and at least one metal oxide among niobium oxide, vanadium oxide, and tungsten oxide. By configuring this, we have achieved an excellent ultraviolet shielding ability in the ultraviolet region of 360 to 380 nm, which is close to visible light.

[Description of the first invention] Structure of the invention The ultraviolet shielding film of the first invention is a composite oxide consisting of cerium oxide and an oxide of a metal having a higher valence than cerium, and contains the oxide of the metal. It is characterized by a weight of 5 to 50 and a weight of 96.

Effect of the Invention The mechanism by which the ultraviolet ray shielding film of the present invention exhibits excellent ultraviolet ray shielding ability is not yet fully clear, or may be considered as follows.

That is, the ultraviolet shielding film of the present invention is made of cerium oxide and an oxide of a metal having a higher valence than cerium. Although this cerium oxide has excellent light transmittance in the visible light range with a wavelength of 380 nm to 780 nm and excellent ultraviolet shielding ability in the wavelength range of 360 nm or less,
The ability to block ultraviolet rays in the ultraviolet region close to 0 nm visible light is low.

However, the ultraviolet shielding film is made of cerium oxide, niobium, vanadium, which is a metal whose valence is higher than that of cerium, and which does not inhibit light transmittance in the visible light range.
By forming a composite oxide with a metal such as tungsten, it is possible to create a new energy level at a level that does not exist only with cerium oxide or with oxides of metals with a higher valence than cerium. . As a result, one of the energy gaps in the level absorbs ultraviolet rays, producing the remarkable effect of effectively blocking ultraviolet rays in the ultraviolet region close to visible light of 360 to 380 nm. I think that the. From this, the ultraviolet shielding film of the present invention can sufficiently block ultraviolet rays with a wavelength of 380 nm or less, and
It seems that a useful film that sufficiently transmits visible light in the range of 80 to 780 nm could be realized.

That is, the short wavelength limit of visible light is 380 nm, and this wavelength corresponds to a band gap of 3.26 eV when converted into energy. Ce O2 to Nb2O5, to 1205
By adding an oxide of a metal with a higher valence than cerium such as WO3, the wavelength limit can be increased to 360 nm (3
, 44 eV) to approach 380 nm (3,26 eV). On the other hand, in visible light, 380nm (3,26eV) ~780n
m (1,58 eV), a composite oxide of cerium oxide-an oxide of a metal with a higher valence than cerium, that is, Ce
O□-Nb205 system, Ce (L-V2O3 system, CeO
The 2-WO3 system has no absorption and is transparent. In other words, there is no change in optical characteristics in the visible range.

Effects of the Invention The ultraviolet shielding film of the present invention can sufficiently block ultraviolet rays with a wavelength of 380 nm or less, and can
This film has the property of sufficiently transmitting visible light in the 780 nm range.

Furthermore, since it is obtained as a film rather than a powder, there is no need to pay attention to the particle size of the product, and when used as an ultraviolet shielding material, there is no need to pay attention to dispersion in a dispersion medium.

[Description of the second invention] Below, a second invention that is a more specific version of the first invention will be described.

The ultraviolet shielding film of the present invention is a composite oxide consisting of cerium oxide and an oxide of a metal with a higher valence than cerium, and the a content of the oxide of a metal with a higher valence than cerium is 5 to 50. The weight is 06.

The oxide of a metal having a higher valence than cerium is preferably at least one of niobium oxide, vanadium oxide, and tungsten oxide.

When niobium oxide is used as an oxide of a metal having a higher valence than cerium, the content of niobium oxide is 10 to 40
Preferably, it is % by weight. When the content of the niobium oxide is less than 10% by weight, the wavelength is 360~3
This is because the ability to block ultraviolet light in the ultraviolet region close to the visible light region of 80 nm cannot be sufficiently improved. Also,
If the content exceeds 40% by weight, the wavelength is 360~
- This is because the ultraviolet shielding ability in the 380 nm ultraviolet region decreases. In addition, the content of the niobium oxide is 25
When the weight is 96 to 35, it is possible to sufficiently improve both the ultraviolet shielding ability in the entire ultraviolet region and the ultraviolet shielding ability in the ultraviolet region with a wavelength of 360 to 380 nm, which is close to the visible light region. It is more preferred because it can improve permeability. Further, it is particularly preferable that the content is about 30% by weight and that cerium oxide and niobium oxide are uniformly dispersed because the shielding area becomes the maximum for the composite of the present system.

Further, when using batdium oxide as the oxide of a metal having a higher valence than cerium, the content of the vanadium oxide is preferably 5 to 50% by weight. Also,
When using tungsten oxide, it is preferable that the content of the tungsten oxide is 10 to 30% by weight. If the content is below the lower limit, the wavelength is 360 to 38
This is because the UV shielding ability in the ultraviolet region close to the visible light region of 0 nm cannot be sufficiently enhanced, and if the content exceeds the upper limit, the ultraviolet shielding ability in the ultraviolet region with a wavelength of 360 to 380 nm cannot be sufficiently enhanced. This is because the value decreases. In particular, the content of vanadium oxide is about 10% by weight, 96%,
Alternatively, when the content of tungsten oxide is about 25% by weight and cerium oxide and vanadium oxide or tungsten oxide are uniformly dispersed, it is particularly preferable because the shielding area is maximized for the composite of this system.

Further, the thickness of the ultraviolet shielding film is preferably about 50 to 500 nm, since the thicker the film, the better the ultraviolet shielding effect will be, or at the same time, the visible light transmittance will be lowered. This is 5
If the thickness is less than 0 nm, no shielding effect can be expected. Also, 500
This is because, if the thickness exceeds 100 nm, even if the film thickness is increased further, the efficiency of the shielding ability relative to the film thickness will only deteriorate. In particular, when the film thickness is 100 to 200 nm, each element is well balanced, which is more preferable.

Next, one of the uses of the ultraviolet shielding film of the present invention is as a highly functional composite material having ultraviolet shielding properties.

The second composite material consists of a substrate made of glass or resin material, cerium oxide formed on the surface of the substrate, and a small amount of niobium oxide, vanadium oxide, and tungsten oxide, which are oxides of metals with a higher valence than the cerium. It is one kind of thing.”
- an ultraviolet shielding layer comprising a composite oxide with an oxide, and the content of the metal oxide is 5 to 50% by weight. This composite material has excellent UV-shielding ability, and the substrate and UV-shielding layer do not separate easily.
Furthermore, the ultraviolet shielding performance does not deteriorate even at temperatures of about 100°C. Note that when this ultraviolet shielding film is formed using transparent glass as a substrate, the composite material maintains sufficient transparency or is lightly colored. The color is reddish-purple or blue.

The ultraviolet shielding film of the present invention can be obtained by forming the film on a substrate made of an inorganic material such as glass or ceramics, or an organic material such as resin.

A specific example of the method for producing the ultraviolet shielding film of the present invention will be briefly described below.

First, an inorganic material such as glass or ceramics, or an organic material such as resin is prepared as a substrate. Next, on the second part of the substrate,
A composite oxide film consisting of cerium oxide and an oxide of a metal having a higher valence than cerium is formed by a physical vapor deposition method such as a sputtering method, a vacuum evaporation method, or an ion blating method.

Among these methods, when the ultraviolet shielding film is formed by sputtering, the substrate is first cleaned and then placed in a vacuum processing apparatus such as a multi-sputtering apparatus.
Evacuate to about 0-6 Torr. Next, a rare gas such as argon gas is introduced to a pressure of about 3 to 5.times.10@-3 Torr, and RF ion etching is performed on the substrate surface. As for the etching conditions, it is sufficient to perform the etching at 30 to 100 W for about 5 minutes. Note that if the substrate is an organic material, the heat resistance is low, so it is preferable that the heating time be 2 minutes or less.

Note that this ion etching may be omitted. Next, a sputtering atmosphere gas such as argon gas or a mixed gas of argon gas and oxygen gas is introduced, and cerium oxide as the target of the present invention and an oxide of a metal having a higher valence than cerium are sputtered into a desired film by RF sputtering. Coat with thick composite oxide.

In addition, in the vacuum evaporation method or the ion blating method, metal pellets I, which are raw materials for the composite oxide film of the present invention, that is, cerium oxide and an oxide of a metal with a higher valence than cerium, are used to coat the substrate with the composite oxide film. Coat metal oxide.

In addition to these physical vapor deposition methods, chemical vapor deposition methods and sol
The composite oxide film can also be formed by a gel method.

Among them, when using the sputtering method,
This is preferable for the following reasons. That is, an oxide can be used directly as a target, and there is no need to include an oxidation reaction in the film formation process, which is convenient.

Through the above steps, the ultraviolet shielding film according to the present invention can be obtained.

The ultraviolet shielding film of the present invention thus obtained can effectively block ultraviolet rays by coating the film, and can also be used as a window glass for automobiles by utilizing its visible light transmittance.
Sky roofs, mirrors, residential window glass, Zanroofs,
It can be used in materials such as eyeglass lenses, as well as automobile interior parts and drug containers, mainly due to its ability to block ultraviolet rays.

〔Example〕

The present invention will be explained in detail below.

First Example A transparent quartz glass was used as the substrate, and cerium oxide (CeO□) and niobium oxide (N b 2○5) were added to the surface of the substrate.
A composite material according to the present invention was manufactured by coating a composite oxide film consisting of the following, and a performance evaluation test of the material was conducted.

First, transparent quartz with a thickness of 2 mm was prepared as a substrate, and the substrate was sufficiently dried.

Next, the prepared substrate was placed in a four-element simultaneous sputtering device, and the cerium dioxide sintered body and the niobium pentoxide sintered body were attached as targets, and the shutters of the remaining two elements of the device were closed). After evacuating the inside of the device to 1.2 x 10-6 Torr, argon gas was pumped to 5.0 x 10 Torr.
-”Introduce up to Torr, R,F.

Two-dimensional simultaneous sputtering was performed using magnetron sputtering.

Cerium dioxide is 500W, niobium pentoxide is 200W
of electricity was input. The substrate was not heated. As a result, a composite material consisting of the substrate of this example and an ultraviolet shielding film having a film thickness of approximately 1100 nm was obtained (sample number 1).

A performance evaluation test of the obtained composite material was performed by a light transmission property evaluation test and a substance identification test.

First, the light transmittance of this sample was determined by
It was measured using a type 0 self-recording spectrophotometer. The results are shown in FIG. Note that NJ in FIG. 1 indicates the results of this example.

Next, the composition of this sample was measured using Rutherford backscattering, and it was found that it contained about 30% by weight of niobium pentoxide.

For comparison, a comparative film was prepared in the same manner as in the above example except that cerium dioxide was used instead of tarded.
7 (thickness: approximately 10,100 nm).The spectral characteristics of the comparison sample were measured in the same manner as above.The results are also shown in Figure 1. In addition, the spectral characteristics of a transparent quartz substrate similar to that described above on which nothing is deposited are also shown in Fig. 1. In the same figure, "C21" shows the spectral curve of a transparent substrate.

As is clear from FIG. 1, it can be seen that the curve "1" according to this example in which niobium pentoxide is mixed shows the highest ultraviolet shielding ability.

The transmittance at a wavelength of 380 nm, which is near the boundary between ultraviolet light and visible light, is that of the comparative film rc deposited with cerium dioxide.
While it is 63% for N, it is 3% for film “1” of this example.
3%, and it can be seen that by mixing niobium pentoxide, the ultraviolet shielding ability near the boundary between ultraviolet and visible light is significantly improved.

In addition, the light transmittance of visible light in the wavelength range of 380 to 780 nm is 82% on average for the comparison film "CI" made of only cerium dioxide, while it is 74% for the film NJ of this example. No significant decrease was found.

As shown in 2 below, the ultraviolet shielding film of this example has a wavelength of 380.
This film has a remarkable effect in satisfying the delicate requirements of shielding at wavelengths less than nm and transmitting at wavelengths larger than nm.

Second Example A UV-shielding film was created by changing the amount of niobium pentoxide added.
A performance evaluation test of the shielding film was conducted to investigate differences in spectral curves depending on the amount of niobium pentoxide added. Below, the first
The explanation will focus on the differences from the embodiment.

The substrate, gas, target, method of coating the substrate with the composite oxide film, etc. are the same as in the first embodiment. The amount of diotide pentoxide added was controlled by the input power. Table 1 shows the input power and composition of each sample. The thickness of each film is approximately 1100 nm.

The amount of niobium pentoxide added is also shown below.

Table 1 The light transmittance of these samples, especially near the visible-ultraviolet boundary region, is shown in FIGS. 2 and 3. The sample numbers in Table 1 correspond to the sample numbers in FIGS. 2 and 3.

As is clear from FIGS. 2 and 3, sample "4" containing 28% by weight of niobium pentoxide exhibits the highest ultraviolet shielding ability. No matter whether the amount of niobium pentoxide added is increased or decreased, the ultraviolet shielding ability of the sample decreases. Although "2" in FIG. 2 contains 10% by weight of niobium pentoxide, its ultraviolet shielding ability is not so high, and if the amount added is less than this, hardly any ultraviolet shielding function can be expected.

On the other hand, "6" in Figure 3 contains 43% by weight of niobium pentoxide, and its ultraviolet shielding ability has already decreased considerably, especially on the low wavelength side.
The shielding ability is lower than that of ``3''.

From these results, it can be seen that in this example, the amount of niobium pentoxide added is preferably in the range of 10 to 40% by weight.

Third Example A transparent quartz glass was used as the substrate, and cerium oxide (CaC2) and vanadium pentoxide (V2O3) were added to the surface of the substrate.
A composite material according to the present invention was produced by coating a composite oxide film consisting of the following in the same manner as in the second example, and a performance evaluation test of the material was conducted in the same manner as in the second example.

That is, ultraviolet shielding films were prepared with varying amounts of vanadium pentoxide added, and a performance evaluation test of the shielding films was conducted to examine differences in spectral curves depending on the amount of vanadium pentoxide added. Hereinafter, the differences from the second embodiment will be mainly explained.

The substrate, gas, target, method of coating the substrate with a composite oxide film, etc. are the same as in the second embodiment. The amount of vanadium pentoxide added was controlled by input power.

Table 2 shows the input power and composition of each sample. The thickness of each film is approximately 1100 nm. In addition, cases in which the amount of vanadium pentoxide added is outside the scope of the present invention are also shown.

Table 2 Of the light transmittances of these samples, especially near the visible-ultraviolet boundary region is shown in FIG. The sample numbers in Table 2 correspond to the sample numbers in FIG.

As is clear from FIG. 4, sample "7" containing 10% by weight of vanadium pentoxide exhibits the widest ultraviolet shielding ability. In sample numbers "8" and "9", as the concentration of vanadium pentoxide increases, the ultraviolet shielding area becomes narrower. However, even sample number "9" containing about 30% by weight of vanadium pentoxide has a considerably wider ultraviolet shielding area than comparative sample "C4" which does not contain vanadium pentoxide.

From these results, it can be seen that in this example, when the amount of vanadium pentoxide added is in the concentration range of about 5 to 50% by weight, it is good as an ultraviolet shielding material.

Fourth Example A transparent quartz glass was used as the substrate, and cerium oxide (Ce02) and tungsten trioxide (WO,) were used on the surface of the substrate.
A composite material according to the present invention was produced by coating a composite oxide film consisting of the following in the same manner as in the third example, and a performance evaluation test of the material was conducted in the same manner as in the third example.

That is, a UV shielding film was created by varying the amount of tungsten trioxide added, and a performance evaluation test of the shielding film was conducted.
We investigated the difference in spectral curves depending on the amount of tungsten trioxide added. Hereinafter, the explanation will focus on the differences from the third embodiment.

The substrate, gas, target, method of coating the substrate with a composite oxide film, etc. are the same as in the third embodiment. The amount of tungsten trioxide added was controlled by input power. Table 3 shows the input power and composition of each sample. The film thickness is
Both are about 1100n. Note that the amount of tungsten trioxide added is also shown, which is outside the scope of the present invention.

Table 3 Among the light transmittances of these samples, especially the vicinity of the visible-ultraviolet boundary region is shown in FIG. The sample numbers in Table 3 correspond to the sample numbers in FIG.

As is clear from Figure 5, tungsten trioxide is 25
The sample containing 1% by weight showed the widest UV-shielding ability. As shown in sample number "10", as the concentration of tungsten trioxide decreases, the ultraviolet shielding area becomes narrower. However, even sample number "10" containing about 13% by weight of tungsten trioxide has a considerably wider ultraviolet shielding area than comparative sample "C5" which does not contain tungsten trioxide.

From these results, it can be seen that in this example, when the amount of tungsten trioxide added is in the concentration range of about 10 to 30% by weight, it is good as an ultraviolet shielding film.

2, 3.4, 5, 6... Ultraviolet shielding film C3 of the second example... Comparative film of the second example 7.8.9... Ultraviolet shielding film C4 of the third example
... Comparative film 10.11 of the third example ... Ultraviolet shielding film C5 of the fourth example
... Comparative membrane of the fourth example

[Brief explanation of drawings]

FIG. 1 is a diagram showing the light transmission characteristics of the ultraviolet shielding film according to the first embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing the light transmission characteristics of the ultraviolet shielding film according to the second embodiment of the present invention. FIG. 4 is a diagram showing the light transmission characteristics of the ultraviolet shielding film according to the third embodiment of the present invention, and FIG. 5 is a diagram showing the light transmission characteristics of the ultraviolet shielding film according to the fourth embodiment of the present invention. FIG.

Claims (1)

[Claims] (1) A composite oxide consisting of cerium oxide and an oxide of a metal with a higher valence than cerium, and the ultraviolet shielding film is characterized in that the content of the metal oxide is 5 to 50% by weight. .