JPH0448095B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sheet that utilizes the phenomenon of light interference to create an extremely elegant pearlescent iris color, and is mainly used as a decorative material. It is intended for use.

[Conventional technology]

The most familiar example of iris color is the hue of a soap bubble, which is characterized by its hue changing variously depending on the viewing angle, but the reason why iris color appears has been known for a long time ( For example, "Knowledge of Optics" by Kogoro Yamada (June 10, 1961, Tokyo Denki University Press, p. 234, etc.).

In other words, by forming a transparent thin film layer (interference layer) with an optical thickness equivalent to an odd multiple of 1/4 of a predetermined wavelength, the light reflected on the surface of the interference layer and the light once incident inside the interference layer are separated. Interference occurs between the light reflected from the surface and the light that emerges from the surface, creating the color of the iris.

Conventional technology related to iris sheets applying this principle includes, for example, as shown in Japanese Patent Publication No. 51-33589, an interference resin film is provided on a light reflective layer, and a semi-transparent layer is provided on top of the interference resin film. An example is an iris sheet.

[Problems to be solved by the present invention]

Although the iris sheet having the above-mentioned structure produces a vivid iris color, it only provides an iris color with so-called glittering transparency.

Depending on the field in which the iris sheet is used, sheets with noticeable glare may not be preferred. If an iris sheet that has an iris color but is opaque, that is, has a pearlescent appearance, can be expected to have a wide range of applications.

An iris sheet with such a pearly feel was completely unknown.

[Means for solving problems]

In view of the above, the present invention has been made as a result of intensive research for the purpose of obtaining an iris sheet with a pearly appearance. To obtain an iris sheet with a pearly feel, characterized in that an interference layer made of brushed resin is provided thereon.

The phenomenon of brushing has been known in the paint industry for a long time. For example, when a paint made of nitrocellulose is applied during the humid summer season, the paint film turns white during drying. This is called water brushing and is explained as follows. If a solvent that evaporates too quickly is used as a solvent for nitrocellulose, the coating surface will lose heat due to the evaporation of the solvent, resulting in a temperature below the dew point, and moisture contained in the atmosphere will reach the uncured coating surface. This water condenses and is dissolved in a solvent such as alcohol that is miscible with water and is included in the paint film, and as the solvent evaporates, the proportion of water increases, causing nitrocellulose to precipitate and brushing of the paint film. It is considered.

In addition to this, another known brushing phenomenon is resin brushing. This is thought to be due to the fact that when mixed solvents are used, the evaporation of each solvent is not well balanced, and the residual solvent's ability to dissolve the resin decreases, causing the resin to precipitate and whiten the paint film.

Needless to say, brushing is an undesirable phenomenon in the paint industry, and in order to prevent it, people add brushing inhibitors such as butyl alcohol, and pay attention to the type and ratio of mixed solvents used. This is the current situation.

The present inventors paid attention to this brushing phenomenon, and
By applying this to the interference layer of an iris sheet, the inventors discovered that a completely new iris sheet with a pearlescent appearance could be obtained, and completed the present invention.

Next, the configuration of the present invention will be explained in more detail.

In the present invention, for example, when creating an iris sheet with a pearly feel using a transparent plastic film as a base, a reflective layer is formed on the plastic film, and then an interference layer made of brushed resin is formed, or vice versa. This can be achieved by first forming an interference layer made of brushed resin on a plastic film, and then forming a reflective layer. At this time, the film does not have to be colorless or may be lightly colored.

If the base is opaque, such as coated paper, it will naturally be necessary to form the reflective layer first, followed by the interference layer of brushed resin. In any of these cases, the iris color is visually recognized from the interference layer side.

The reason why an iris color with a pearlescent appearance can be visually recognized with the above configuration is considered as follows. Brushing of a resin means that a portion of the incident light is diffusely reflected by the surface, and this diffusely reflected light and the light that passes through the interference layer, is reflected by the reflective layer, and comes out to the surface. The color of the iris is visible due to interference between the iris and the other light, but because the resin is whitened (blushing), the pearlescent appearance is greatly emphasized. The inventors previously filed a patent application in 1983-
In No. 225037, we filed a patent application for a pearl-like iris sheet in which a semi-transparent light layer was further provided on this brushed interference resin layer, but even without the semi-transparent layer, a pearl-like iris sheet could be obtained. We have discovered that coloring appears and have filed a new application for the present invention. The iris sheet described in Japanese Patent Publication No. 51-33589 mentioned above has a non-whitened resin layer as an interference layer, so there is very little reflection on the surface of the resin layer, and therefore a semi-transparent layer is formed on the resin layer. Unless it forms, the iris color cannot be clearly seen.

Moreover, the iris color obtained in this way becomes a transparent and glittering iris color as described above.

The reflective layer of the present invention can be made of, for example, aluminum, gold,
A metal such as silver, copper, tin, chromium, nickel, or titanium is formed on a base such as a film or paper using a known method such as a vacuum evaporation method, a sputtering method, or an ion plating method. Further, a metal foil with excellent surface gloss may be used as it is or in the form of being bonded to another sheet.

In the case of a metal thin film formed by vacuum evaporation or the like, if the film is too thin, it will not be able to function as a reflective layer, so it must be formed to have a white light transmittance of 55% or less. In the case of an aluminum thin film, a white light transmittance of 55% corresponds to a thickness of approximately 50 Å.

The present invention requires that the interference resin layer be brushed as described above. If the degree of brushing is too low, the pearly iris color that is the objective of the present invention cannot be obtained;
Moreover, if the amount is too large, the resin layer becomes opaque and naturally does not function as an interference layer. Further, the thickness of the interference layer must be formed within a range that causes interference, and although the thickness varies depending on the desired hue, it is usually formed within the range of 1500 Å to 25000 Å. Therefore, the degree of brushing may be adjusted as appropriate depending on the thickness of the interference film and the desired degree of pearlescent appearance. Also, the degree to which brushing occurs varies widely depending on humidity, so
It is also necessary to control humidity appropriately. Further, the degree of brushing can be increased by adding a small amount of water to a hydrophilic solvent such as alcohol or acetone in advance.

As a result of various studies, the present inventors found that when the light transmittance of the interference resin layer for white light without brushing is 100%, the transmittance when brushing occurs is 30% to 95%. It has been found that this is a preferable range in which the object of the present invention can be achieved. The method for causing brushing may be either the water brushing or resin brushing described above.

As the resin, nitrocellulose, epoxy resin, acrylic resin, and other known resins may be used alone or in combination of two or more. At this time, there is no problem in using a colorant together with the resin as long as it does not impede the purpose of the present invention. Rather, by coloring, an iris sheet with a pearly feel rich in layered elegance can be obtained. In addition, when forming the interference resin layer, for example, by periodically moving a wire bar, a hairline pattern can be formed, or by adding silicone to partially change the thickness of the resin layer, it is possible to create a more elegant pattern. It is possible to produce an iris sheet with a rich pearly feel. Furthermore, by forming several interference layers brushed with resins with different refractive indexes, a more elegant iris color can be expressed.

The pearlescent iris sheet of the present invention can also be bonded to other sheet materials such as paper, nonwoven fabric, cloth, leather, synthetic leather, and plastic sheets.
It can also be embossed. Possible uses include wallpaper, furniture upholstery, interior decoration, box exteriors, book bindings, book covers, paper bags, origami, artificial flowers, gold and silver paper, toys, labels, and a wide range of other products.

Example 1 A light reflecting layer was formed on a 12 μm thick polyester film by depositing aluminum to a thickness of 500 Å using a vacuum deposition apparatus at 1.0×10 ⁻² Pa according to a conventional method. Next, an interference resin layer having the following composition was coated using a reverse roll coater with a target thickness of 7500 Å. The coating film causes brushing, and when applied under the same conditions to a film without a reflective layer, the transmittance of white light is approximately
It was 92%.

Methyl methacrylate resin 65 parts by dry weight Nitrocellulose 4 Acetone 110 parts by weight Toluene 150 The obtained iris sheet had an extremely elegant pearly iris color that could be visually recognized.

Example 2 A coating liquid with the following composition was applied to a 12 μm thick polyester film using a gravure roll coater. Immediately after coating, a hairline pattern was created by bringing a #3 wire bar into contact with the coated surface and periodically moving it from side to side. An interference layer with an average thickness of about 4500 Å was formed. At this time, the average transmittance of white light was 75%.

Methyl methacrylate resin 65 parts by dry weight Nitrocellulose 6 Acetone 110 parts by weight Toluene 150 Next, using a vacuum evaporation apparatus and according to a conventional method, a light reflective layer of aluminum was deposited at a pressure of 1.1×10 ^-2 Pa at a pressure of 500 Pa.
Å was deposited. When the obtained iris sheet was viewed from the film surface, an extremely elegant hairline pattern with a pearlescent iris color was visible.

Claims (1)

[Claims] 1. On the light reflective layer, with a thickness of 1500 to 25000 Å,
An iris sheet with a pearly feel characterized by having a brushed resin layer with a light transmittance of 30 to 95%.