JPH0777840B2 - Decorative article with multicolor effect - Google Patents

Abstract

An article exhibiting a multicolor effect is obtained by combining a transparent substrate, an interference pigment and an absorption colorant, the pigment and colorant preferably united in the form of a combination pigment, in which the absorption colorant is of a color which is different from the transmission color of the interference pigment or the complement thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to decorative articles having a multicolor effect.

b. Composition of the invention Historically, interference pigments have been a type of pearlescent pigment, ie a pigment that has an effect similar to natural pearls. This pigment consists of thin platelets that are transparent in the visible region of the spectrum. The plaque is very smooth and reflects some of the light striking it and some of it. Some of the transmitted light is then reflected by another layer of the platelet. As a result, many reflections occur from many layers, creating a depth of gloss because the human eye cannot focus on one particular layer.

The reflections that occur are diametrically opposite, as the angle of incidence and angle of reflection are equal. The amount of light reflected at the diffuse reflection angle is small, and the amount of reflected light decreases rapidly as it deviates from the specular reflection angle. Therefore, pearlescent pigments are extremely sensitive to the viewing angle. The platelets must be extremely smooth to maximize the amount of light reflected. Rough surfaces scatter light diffusely, reducing the gloss effect.

For maximum reflectivity, the platelets should be arranged parallel to each other and parallel to the support. Without this alignment, the light would be reflected indiscriminately, with a corresponding reduction in gloss. The amount of light reflected depends on the refractive index of the platelet. The higher the refractive index, the greater the amount of reflected light.
In most cases, the platelets will be present in the film-forming material with a refractive index of about 1.5, so the refractive index of the platelets should be well above 1.5.

In the case of natural pearls, the layer of reflective material is composed of calcium carbonate interposed between each layer of organic material. Synthetic pearlescent pigments are made by growing crystals of basic lead carbonate and bismuth oxychloride. Both the basic lead carbonate and bismuth oxychloride can be grown into extremely smooth crystals. Recently, titanium dioxide, which by itself does not grow into smooth crystals, has been used coated onto thin, smooth platelets of mica that act as carriers. The ideal length of this mica platelet is 5 to 50 microns. The titanium dioxide coating applied usually has a thickness of 60 to 160 nanometers.

It is known that coating titanium dioxide with a thickness of 60 nanometers on mica gives pearlescent or white lustrous pigments. Increasing the thickness of titanium dioxide causes interference of light and causes iridescence. Therefore, it is possible to create a color using only a transparent layer of titanium dioxide. The colors found in oil slicks or soap bubbles are examples of interference colors. The color of the oil film or soap bubbles disappears when the oil film or soap bubbles disappears. However, the color from the interference pigment is permanent and, when mixed with the film-forming material, can impart color to the film-forming material. Not only do interference pigments impart color, but their structure can also act to impart gloss.

Other materials besides titanium dioxide can also be used as the mica coating. Examples of such substances include ZrO ₂ and Sn.
O _2, ZnO, there is _{Fe 2 O 3, Cr 2 O} 3, V 2 O 5 and their hydrate. These oxides exist in various crystal forms. For example,
TiO ₂ may be anatase or rutile or a mixture of both. Combinations of two or more metal oxides can be used in various crystalline forms.

Interference pigments can reflect any color in the visible spectrum, provided they are of suitable thickness. These colors range from yellow to red, blue and green. It is also possible to vary slightly between these colors. Complementary colors are created by transmission, as reflected colors are created by interference effects. Thus, if red is produced by reflection from the interference pigment, green can be seen in the transmitted light of the pigment.

When interference pigments are added to the film-forming material and coated on a white background, two colors can be seen depending on the viewing angle. That is, the reflected color can be seen near the regular reflection angle, and the transmitted color can be seen at another angle.

To increase the reflected color, absorbing pigments are added to the interference pigments. In most cases, the absorbing pigment is deposited on the interference pigment,
Generate the essential parts of the plaque. Thus, for example, depending on the viscosity, depositing yellow to red Fe ₂ O ₃ on the yellow interference color will intensify the yellow color. The yellow color of Fe ₂ O ₃ increases the interference yellow color, producing a shiny deep yellow color. The above pigment obtained by adding an absorbing pigment to an interference pigment to enhance the color strength is called a combination pigment.

Besides Fe ₂ O ₃ , other colorants have also been used. Dark blue is added to increase the interference color of red and Cr ₂ O ₃ is added to increase the green color.

When mica is coated with a colored oxide, the final absorption color changes in combination with the added colorant. The absorption color does not change when mica is used in the coating as colorless oxides.

The concentration of the absorbing pigment is adjusted so that the intensity of the color produced is comparable to the interference color. If the concentration of colorant is too high, the absorbing colorant will obscure the interference color and no color enhancement will occur. To enhance color, in the case of TiO ₂ coated mica, the colorant is added at a concentration of about 2% to 5% by weight of the titanium dioxide coated mica.

For various interference colors, not only absorption pigments of the same color as this interference color, but also various absorption colorants can be added. Thus, for example, it is possible to add a red absorbing pigment (carmine) to a blue interference pigment.

If the color of the absorbing colorant differs from the interference color, an interesting color effect will result, depending on the background and the viewing angle. The colorant concentration is so low that when the combined pigment is spread over a black background, the black absorbs the color of the colorant and only the reflected color of interference is observed. This can be actually confirmed by observing the pigment at a normal angle or at a glancing angle.

When the combined pigment is dispersed in the film-forming material and coated on a white background, two different colors can be observed, depending on the viewing angle. At normal viewing angles, the reflected color of the interference pigment is visible. At the divergence or glancing angle, the reflected color of the interference pigment is no longer observed, but the color of the absorbing pigment is visible. Thus, by changing the viewing angle from the normal sensitivity to the glancing angle, the color changes from the interference reflection color to the absorption pigment color. For this reason, a very beautiful and aesthetically pleasing color effect can be obtained.

Combination pigments are used to coat white, gray or black substrates and can be added to cosmetic formulations such as eye shadows where a color change is desired.

A third color that can be generated has now been found and is the subject of the present invention. A third color is seen when the known combination pigments are added to a transparent film-forming material and coated on a transparent support such as glass, acrylic sheets and the like. This third color is different from both the reflective color and the color of the absorbing pigment. The third color is produced by mixing the transmitted color of the interference pigment and the color of the absorbing pigment. Until now, the third color was not seen because the combination pigment was not used on a transparent support.

Interference pigments made from titanium dioxide coated mica were used as the basic support to illustrate the colors that could be produced. Four types of interference colors, yellow, red, blue and green were used. In addition, yellow (Fe ₂ O ₃ ), red (carmine), and blue (Cr ₂ O ₃ ) were used as absorbing pigments. A total of 16 samples were prepared by depositing each absorbing colorant on the interference pigment. The concentration of the colorant was 2% to 5%. Other colorants can be used in place of the colorants selected in these examples.

After appropriate treatment, the combination pigment was added to a 9.5% solids nitrocellulose lacquer at a concentration of 3%. A film in which the combined pigments were dispersed in a nitrocellulose lacquer was formed on a glass slide using a bird film applicator. This resulted in a wettable film of about 0.08 millimeters (about 0.003 inches).
When the film was dried, the platelets were aligned parallel to the film.

The above dry film was observed at normal incidence, at a diffusion angle or a glancing angle, and finally at a specular color by transmission, and a visual inspection was conducted during the daytime. The observer stood against the sun and grasped the slide so that the light hits the surface of the slide and reflects like a mirror back to the observer. In the case of diffuse reflection, the slide was held toward the light so that the light hits the slide surface at a glancing angle and is reflected to the viewer. For transmission,
The slide was gripped against the light. Record the colors you see,
The results of these observations are shown in Table 1. For comparison, Table 1 also shows the results of observations made with interference pigments containing no absorbing pigment. The combinations that show the most sharp three-color effect are marked with an asterisk.

These examples demonstrate that a new color is produced when the color of the absorbing pigment differs from the reflective color of the interference pigment or its complement (transmission color). For example, a red colorant deposited on a yellow interference pigment (transmitted color is blue) produced a third color upon passage, namely purple. A green colorant on the same yellow interference pigment produced a bluish green color upon transmission.

From the above, various colors can be produced depending on the type and concentration of the absorbing colorant used. The higher the concentration of the colorant, the closer the color obtained will be to the color of the colorant. If the concentration of the coloring agent is too high, the transmitted color is suppressed and becomes unclear, and only the absorbing coloring agent is seen. Therefore, the concentration of absorbing colorant is determined by the intensity of the transmitted color. In the case of commercial interference pigments, it has been found that an interesting third color is obtained with absorbing pigment concentrations of 2% to 5%.

The combination pigments listed in the table to demonstrate the third color effect had the absorbing pigment deposited directly on its surface. A similar effect can be obtained by separately dispersing the absorbing colorant and the interference pigment in the film-forming material. In this case, the absorbing colorant is dispersed throughout the film rather than being concentrated in each platelet. This gives nearly similar results, although not exactly equal. As expected, different concentrations of colorant are required and these concentrations can be easily determined with a few routine experiments.

The object coated with the combination pigment, as long as it is transparent or translucent, transmits some light, can be coated with the combination pigment, or can be mixed with this pigment,
Any object will do. Examples of such an object include a glass pin, a glass sheet, a transparent acrylic sheet, and a polyester sheet.

c. Examples Example 1 A combination pigment of a yellow absorbing colorant and a red interference pigment was added,
Dispersed in water based acrylic polymer emulsion. This dispersion was prepared by adding about 3 g of emulsion to 3.0 g of the combined pigment and stirring thoroughly. Then 94g
The above emulsion was gradually added with stirring to prepare a combined pigment in the form of an emulsion having a concentration of 3%. The pigment emulsion was then applied with a brush to a 6.4 millimeter (1/4 inch) thick clear colorless acrylic sheet and the emulsion dried. Pieces were then cut from this sheet. When viewed at specular angles, each piece showed a red interference color, a yellow at glancing angle and a yellow-green at transmission.

Similar pieces were prepared from various combination pigments. These pieces were pasted on a large acrylic panel and various patterns were drawn to create a stained glass-like object.

Example 2 A combination pigment of a blue interference pigment and a red absorbing colorant,
Dispersed in clear thermoset acrylic enamel (AT56, Rohm & Hass Co.) and diluted 2: 1 with xylene.
Add about 3 g of thermosetting acrylic resin to the combination pigment of g,
Prepared by thorough stirring. Then 94 g of acrylic enamel was added with stirring. The pigment acrylic enamel was applied to a large clear glass ball approximately 60 centimeters (24 inches) in diameter. This application was performed using a conventional air spray gun. This coating formed two layers. The coating was cured in an oven at 120 ° C for 30 minutes. When looking directly at the ball, it looked blue reflected.
The side surface of the ball showed a red absorption color, and the back surface of the ball showing the transmission color showed an orange color. These colors are a mixture of several colors, producing interesting aesthetic effects and pleasing the eyes of the viewer.

Example 2A The ingredients of the combined pigment of Example 2 were added to the acrylic lacquer of Example 2. First, the red colorant and then the blue interference pigment were dispersed therein. The color effect of the coated balls was similar to that of Example 2.

Example 3 A combination pigment of a yellow interference pigment and a red absorbing pigment was dispersed in a nitrocellulose lacquer. This dispersion is 3.
Prepared by mixing 0 g of pigment with 3 g of 9.5% solids nitrocellulose lacquer. After mixing well, add another 94
g of nitrocellulose lacquer was added with stirring.
Next, the Bird Film Applicator
Applicator) was used to form a film on a glass slide with particles dispersed in nitrocellulose. This gives about 0.076 mm (about 0.003 inch)
Of a wet film was formed. The film was then air dried. Next, the glass slide was cut into rectangular pieces measuring 5 cm (2 inches) in width and 7.6 cm (3 inches) in length, and these piece slides were processed so that they could be hung with wire or string.

Similar slides were prepared using a combination of red colorant and yellow interference pigment and a combination of yellow colorant and dyed interference pigment. Next, when the slides were hung from strings such as mobiles, each slide slowly rotated due to the flow of air, and a beautiful color effect was seen, and in other aspects, various colors were seen due to reflection and transmission. .

Example 4 A combination pigment of blue colorant and green interference pigment was dispersed in low density polyethylene. 950 g of Eastman Chemicals Tenite 19
25F was put into the Banbury mixer. The plastic was mixed and melted. Then add 50 to this molten plastic.
Grams of the above combined pigments were gradually added and mixed with stirring for 10 minutes. After mixing, throw the colored plastic into the pan and immediately start the boling stewart.
d) Place in a hot rolling mill and press the colored plastic between two hot rolls to a thickness of 0.64 cm (1/2
A slab of from 1 inch to 1.3 cm (1/4 inch) was formed. The slab was scored with a razor, cooled and crushed into small pieces. This was then coarsely crushed in a Cumberland Granulator. After crushing, the material was placed in a Killian Extruder and extruded through a sheet forming die to form a sheet about 4 mils thick. Green was seen at the specular angle, blue was seen at the glancing angle, and purple was seen by transmission. Similar sheets were made using different combinations of pigments, all of these sheets were cut into various shapes and affixed to a transparent support (for example between two sheets of glass) for a myriad of colors. I was able to create an artistic work that I had.

As can be seen from the above examples, the combination pigments can be applied to the support by methods known in the art. As a coating method, a brush, a roll, a knife, a pressure roll, an engraving roll, dipping, an air blade,
There are methods such as using air spray, electrostatic spray, airless spray, and fluidized bed. The colored plastic can be molded by any known method. Such methods include compression molding, injection molding, extrusion and blow molding. These plastics also
It can be cast in various ways.

Examples of usable thermoplastics include cellulose acetate, cellulose acetate butyrate, polycarbonate, polyethylene, polypropylene and polystyrene.
Thermosetting plastics include epoxy resin, phenol-formaldehyde acrylic resin, polyester, polystyrene, polyurethane and the like.

Claims (19)

[Claims] 1. A transparent object, an interference pigment and an absorbing colorant, the absorbing colorant having a color different from the reflection color of the interference pigment or its complementary color, and the interference pigment and the absorbing colorant on the transparent object. Characterized in that it is coated or contained in said transparent object, whereby it is able to exhibit a reflection color of the interference pigment, a color of the absorbing colorant and a third color different from said two colors. An article that exhibits a multicolor effect. 2. An interference pigment and an absorbing colorant are combined,
The article of claim 1 producing a combination pigment. 3. The article of claim 1, wherein the interference pigment and the absorbing colorant are separately dispersed in the body. 4. An article according to claim 1 wherein the absorbing colorant is selected from the group consisting of iron oxide, carmine, dark blue and chromium oxide. 5. An article according to claim 1, wherein the interference pigment is titanium dioxide coated mica. 6. The interference pigment is titanium dioxide coated mica,
The article of claim 4, wherein the amount of absorbing colorant is about 2-5% by weight, based on the weight of the interference pigment. 7. The article according to claim 1, wherein the interference pigment exhibits a gold color and the absorbing pigment exhibits a purple color. 8. An article according to claim 1, wherein the interference pigment exhibits a red color and the absorbing pigment exhibits a yellow or green color. 9. An article according to claim 1, wherein the interference pigment exhibits a blue color and the absorbing pigment exhibits a red color or a green color. 10. An article according to claim 1, wherein the interference pigment exhibits a green color and the absorbing pigment exhibits a yellow or blue color. 11. A multicolor effect characterized in that an interference pigment and an absorbing colorant having a color different from the reflection color of the interference pigment or its complementary color are coated on or contained in the transparent object. Of manufacturing an article showing. 12. The method of claim 11, wherein the interference pigment and the absorbing colorant are combined to form a combined pigment. 13. The method of claim 12 wherein the absorbing colorant is selected from the group consisting of iron oxide, carmine, dark blue and chromium oxide. 14. The method of claim 11 wherein the interference pigment is selected from the group consisting of titanium dioxide coated mica and iron oxide coated mica. 15. The interference pigment is titanium dioxide coated mica and the amount of absorbing colorant is about 2 to 5 relative to the weight of the interference pigment.
15. The method of claim 14, which is in weight percent. 16. The method according to claim 13, wherein the interference pigment exhibits a gold color and the absorbing pigment exhibits a purple color. 17. The method according to claim 13, wherein the interference pigment exhibits a red color and the absorbing pigment exhibits a yellow color or a green color. 18. The method according to claim 11, wherein the interference pigment exhibits a blue color and the absorbing pigment exhibits a red color or a green color. 19. The method according to claim 11, wherein the interference pigment exhibits a green color and the absorbing pigment exhibits a yellow or blue color.