JPH03120351A - Additive for molding plastic and plastic molding containing same - Google Patents

Abstract

PURPOSE:To provide a color tone which varies when viewed from a different direction to a molding and also to provide a cubic impression to the color by coating the surfaces of a base material with optical interference films, reducing the above base material into powder or small pieces, and adding the resulting powder or small pieces to a molding material. CONSTITUTION:An interference film 2 is formed on the surface of a base material 1 made of mica, etc., by successively laminating a high-refraction film 3 of TiO2, etc., a low-refraction film 4 of SiO2, etc., and a high-refraction film 5 of TiO2, etc., on the above surface. The interference film 2 is also formed on the opposite surface of the base material 1 in a similar manner as above. This base material 1 is cut and further cleaved into a state of powder or small pieces. The resulting powder or small pieces are used as an additive for molding plastics and added to a transparent casting resin, and the resulting mixture is molded. When the light from outside penetrates into the resulting molding and strikes on the additive, a green color, as an interference color, is allowed to appear in various color tones by means of the interference action of the light due to the interference films 2. Since the interference films 2 are scattered at various angles, the color can be allowed to appear in different color tones according to the angles of view.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a plastic molding additive for coloring a plastic molded product, and a plastic molded product molded by adding this additive to a molding material. It is.

[Prior Art] Conventional plastic molded products use inorganic or organic pigments such as rutile titanium oxide, cadmium maroon, and calcium resol toner, or brass as molding materials.

Metal powders such as aluminum and gold were added to the molding material to create the desired color or metallic tone.

[Problem to be solved] Plastic molded products made by adding such additives have the same color throughout and have a monotonous color tone.
There is no change in color tone even when viewed from different directions, and the three-dimensional effect of colors is lacking. For this reason, when used as a member for which decorativeness is important, such as the outer frame of a watch, there are many cases in which a sufficient sense of satisfaction cannot be obtained.

The purpose of the present invention is to provide an additive for plastic molding that can give different color impressions when viewed from different directions and give a three-dimensional effect to the color of a molded product, and a highly decorative molded product made by adding this additive. Our goal is to provide plastic molded products.

[Means to solve the problem]

In order to achieve the above object, the additive for plastic molding of the present invention is made by powdering or pulverizing a base material whose surface is coated with an interference film having a thickness capable of producing a desired color by interference of light. This is what I did.

Moreover, the plastic molded article of the present invention is molded by adding this additive to a molding material.

[Operation] When light is incident on the interference coating on the surface of the base material, an interference color corresponding to the thickness of the coating appears. Molded products made by adding additives made from powdered or small pieces of such base materials to plastic molding materials have fine interference films of each of the additives mixed in the molding material in arbitrary orientations. , the angle of incidence of light is different, and various interference colors occur, resulting in a variety of color tones.

[Example] Example 1 As shown in the figure, in this example, mica, which is a material with high interfolding property, is used as the base material 1, and a high refractive film 3. Low refractive film 4. The high refractive films 5 were sequentially laminated to form an interference film 2 consisting of three layers.

A method for forming the three-layer interference coating 2 will be described below.

First, titanium oxide was coated on the surface of the base material 1 as the high refractive film 3 . In this example, a sputtering method is adopted, using metallic titanium (Ti) as a sputtering target, argon gas as a sputtering gas, and the pressure of oxygen injected into a chamber (not shown) that is reduced to a certain pressure. (oxygen partial pressure) 3 x 10-2
Direct current reactive sputtering was performed with a DC output of 4.6 W/c. At this time, so that the high refractive film 3 emits a green interference color, the thickness of the film is λ/4 of the wavelength λ of green light - 5500 angstroms.
The sputtering time was set to form up to 375 angstroms. In this way, titanium oxide (
A high refractive index s3 consisting of TIO2) was obtained.

Next, on the high refractive film 3, a low refractive film 3 made of silicon oxide (S t O2) is formed by sputtering.
was formed to have a thickness of 1375 angstroms, and furthermore, a high refractive film 5 made of T 102 was again formed to a thickness of 1375 angstroms, and the three layers were laminated to form the interference film 2. A three-layer interference coating 2 was also formed on the opposite side of the base material 1 using the same method.

The mica piece on which the interference wave l112 was formed in this way is cut into an appropriate size, and then cut into pieces of several to several tens of hours using a mortar or the like.
The mixture was folded and powdered to produce an additive for plastic molding according to the present invention.

The above-mentioned powdered additive material was added to a transparent casting resin such as acrylic, unsaturated polyester, or epoxy in an arbitrary ratio and molded to obtain a plastic molded article of the present invention. These plastic molded products have powdered additives mixed in a transparent body at an appropriate ratio, so when light from the outside enters the transparent body and hits these additives, each additive is Due to the interference effect of light caused by the interference coating 2 of the material, green, which is an interference color, appeared in various tones. Furthermore, since the interference wave II%2 is scattered at various angles, it appears in different tones depending on the viewing angle.

Example 2 An aluminum foil having a thickness of several tens of micrometers was used as a base material, and a three-layer interference coating was formed on the surface of the aluminum foil as a base material in the same manner as in Example 1. This was cut into small pieces of a desired size and used as an additive for plastic molding. This additive material has a high reflectance of the base material, so interference colors are likely to occur.
Depending on the viewing direction, interference colors may appear, or a silvery-white luster, which is the background color of aluminum, may appear.

This additive material was added in an appropriate ratio to a transparent acrylic casting resin and cured to obtain a plastic molded product.

Depending on the angle of the mixed additives, this molded product had parts where interference colors appeared inside, and parts where no interference colors appeared and the background color, silvery white, appeared, resulting in a discontinuous and diverse range of color tones. .

Other Modifications In Example 1, the high refractive film 3. An example was shown in which a three-layer interference coating 2 consisting of a 4° low refractive film and a high refractive film 5 was formed.
These three layers of interference coatings can also be formed by stacking them multiple times. This improves wavelength filtering performance and produces sharper color tones.

In these embodiments, the thickness of the interference coating 2 can be varied by varying the sputtering time to produce a molding additive that produces a desired interference color.

For example, red wavelength λ - 7200 angstrom λ/
By forming the coating No. 4, a red interference color can be obtained. In this way, several types of additives for plastic molding that appear in different interference colors such as red, yellow, blue, and green are manufactured, and if these are mixed and added in appropriate proportions to manufacture plastic molded products, even more The color will appear.

Furthermore, it is also possible to pelletize the resin mixed with the additive of Example 1 using a pelletizer and use it as an injection molding material.

It is also possible to use powder as a base material and form an interference film on the surface thereof by sputtering or the like. In this case, an interference film is formed around the entire circumference of each powder, so
Interference colors appear when viewed from any direction.

Examples of materials that form interference films are shown below along with their refractive indexes.

Since interference coatings made of these substances are chemically stable substances, they are less prone to fading or discoloration.

In the above examples, the sputtering method is used as the film forming method, but the coating method is not limited to this, and other methods that can produce interference films such as ion blating method and vacuum evaporation method are also possible. It is fine as long as it is something.

In the above example, the interference coating is formed of three layers, but the number of coatings is not limited to this, and it is possible to obtain a desired interference color with one layer. It is also possible to do so.

Furthermore, the molding method is not limited to the cast molding method.
Compression molding method, extrusion molding method, injection molding method if the oil additive is powdered, etc. are employed as appropriate.

[Effects] As explained above, the plastic molding additive of the present invention can provide a desired interference color to the container by changing the thickness of the interference film formed on the surface of the base material. In addition, since the additive interference coating is a chemically stable substance, there is little fading or discoloration, making it an extremely excellent additive for plastic molding. Plastic molded products made using this additive material can be colored in any desired color through the optical effects of the additive material, making it possible to obtain molded products that have different colors or shades of color depending on the viewing direction. . In addition, since the additives are placed facing various angles, the interference color has a rich three-dimensional effect and a variety of color tones.
It is ideal for cases where high decorativeness is required, such as in the frame of a watch.

[Brief explanation of the drawing]

The drawing is an enlarged sectional view showing the plastic molding additive of the present invention in a state before it is powdered or made into small pieces. 1...Base material, 2...Interference coating. that's all

Claims (2)

[Claims] (1) An additive for plastic molding made by powdering or breaking into small pieces a base material whose surface is coated with an interference film thick enough to produce a desired color by light interference. (2) A plastic molded article formed by adding the additive according to claim 1 to a molding material.