JPH03173626A - Manufacture of design sheet - Google Patents

Abstract

PURPOSE:To provide complementary color relation between the hue of reflected light and that of transmitted light and to effectively develop the same to the max. with good contrast by forming a film under a manufacturing condition of a specific draw ratio by an extrusion method in order to uniformly disperse and orient particles formed by coating the surfaces of fine scaly mica particles having specific thickness with titanium dioxide in a specific range of thickness in transparent plastic. CONSTITUTION:A resin is used as vehicle and scaly mica coated with titanium dioxide in a membrane form is dispersed in the resin. Titanium dioxide used herein may be a rutile type or an anatase type and the thickness thereof is pref. 30-500mum. As scaly mica, white mica nearest to a colorless and transparent state obtained by a wet method obtaining one having a smooth surface is pref. This white mica pref. has thickness of 0.05-2.0mum and a size of 10-20mum. A draw ratio is represented as the ratio of the lip gap of a die and the thickness of an actually obtained film sheet and, as a condition, by setting the draw ratio to 20-100, the sufficient orientation of particles is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a color-changing plastic sheet, a decorative sheet in which the colors of reflected light and transmitted light have a complementary color relationship. It is something.

[Conventional technology]

Conventionally, the most basic and widely used method for coloring plastics is to uniformly disperse inorganic or organic colorants into resins. With this method, the pigment absorbs part of the white light that is irradiated, and the other part is transmitted or reflected, resulting in a color that is produced by selective absorption, so the color of the plastic surface does not appear artificial or random. The flat colors give it a monotonous feel.

It is also common and often used to give indications or designs by applying multicolored letters or photographs to the surface of plastics using printing techniques such as gravure printing or offset printing. Using this printing technology, it becomes possible to freely add designs to the surface of plastics, and the amount of information that can be displayed becomes enormous. However, the design lacks depth in color and lacks three-dimensionality.

Recently, in order to create this three-dimensional effect, a method has been used to enhance the design by rolling light. For example, by creating fine irregularities on the surface in a certain direction, parts that reflect light and shadows are used. Parts are consciously created to create effects. Alternatively, metals such as aluminum, gold, and silver can be vapor-deposited on the surface, or particles can be printed with an appropriate vehicle to give a partially glossy appearance, or they can be made to look three-dimensional by using light interference like porodaram. This method is also becoming more popular.

Under these circumstances, a technology has been developed that uses particles of microbial scale-like mica coated with titanium dioxide (burr pigments) to produce iris colors or interference colors, giving it luster and a decorative effect such as metallicity and luxury. In the paint and printing methods, there is a method of orienting the paint in a certain direction depending on the characteristics of the paint itself, such as lacquer for imitation pearls, to fully realize its effect. Although there are methods for orienting molded products such as centrifugal casting, slide casting, and vibration methods, there is no sufficient method for molding techniques.

"Problem to be solved by the invention" The purpose of the present invention is to
By uniformly dispersing the pigment into transparent plastic without crushing it, and by orienting the pigment in one direction, the colors of the reflected light and transmitted light are complementary colors. The object of the present invention is to form a decorative sheet by an extrusion method that is durable, has good contrast, and can maximize its effects.

[Means to solve the problem]

That is, the present invention has a thin flake shape with a thickness of 0.5 to 2.
Draw 1L 20-100 was produced by an extrusion method in order to uniformly disperse particles coated with titanium dioxide with a film thickness in the range of 30 to 500 mμ in a transparent plastic and to orient them. This is a method for producing a decorative sheet, which is characterized by forming a film under certain conditions.

The transparent plastic used in the present invention may be any thermoplastic resin, regardless of whether it is crystalline or non-crystalline, as long as it can be processed into a film sheet by extrusion. For example, polyvinyl chloride (PV)
C), or polypropylene (PP), polyethylene (P
Olefin resins such as E) or polyester resins (
PET, PETG) or polycarbonate-1-(PC)
Engineering plastics such as polyacrylonitrile (PAN), polymethyl methacrylate (P
Acrylic resins such as MMA) or borisdylene (PS
) and other transparent resins.

Using this resin as a vehicle, flaky mica coated with a thin film of titanium dioxide is dispersed.

The titanium dioxide mentioned here may be of rutile type or anatase type, and its thickness is preferably 30 to 500 mμ. It is preferable that the scaly mica be obtained by a wet method, which produces muscovite which is closest to colorless and transparent and has a smooth surface. Also, its thickness is 0.05 to 2.0 lt m
However, the preferred size is 10 to 200 μm.

The principle behind how the Plus Deck sheet develops various hues is that among the light rays that enter the sheet, light is reflected at the boundary between the titanium dioxide-coated mica vehicle and titanium dioxide, and light is reflected at the boundary between titanium dioxide and mica. It appears when the light interferes with the light. Therefore, the color developed is determined by the thickness of the titanium oxide film and the mica layer, and with respect to the light that passes through the sheet, only the light of the wavelength that is transmitted without being reflected by the titanium dioxide-coated mica is visible. Therefore, the hue when the sheet is viewed with reflected light and the hue when viewed with transmitted light have a mutually complementary color relationship.

The strength of this color development, that is, the color density, depends on the amount of the titanium dioxide-coated mica added to the vehicle, and also changes in the arrangement of the titanium dioxide-coated mica in the vehicle. The amount added can be varied depending on the thickness of the film and the intended use, but is preferably from 0.5 to 10 parts thick. Regarding the arrangement, it is important that the plate-like surfaces of the scaly mica are arranged in a fixed direction in each particle, as shown in FIG. Even if they are not arranged, the hue will be shown, but the intensity of the color will be weak. Furthermore, if the particles are crushed into small pieces during manufacturing, the color development will be dull.

With these points in mind, when obtaining a decorative sheet as described above, extrusion is most suitable.

[For production]

The extrusion method is a method used for manufacturing thermoplastic resin films and sheets.The resin is heated to above its softening point in a barrel or cylinder, and the composition is uniformly mixed with a screw. In this method, the resin composition is mixed and diffused, extruded from a die, and then formed into a film sheet using a mirror-finished cooling roll and a guide roll, and then wound up.

At this time, when force is applied by pulling the resin in the flow direction (winding direction) in order to align the orientation of the titanium dioxide-coated mica in the resin, the plate-like surface of the mica particles becomes parallel to the surface of the film sheet. I found that it is lined up with . This pulling force can be applied by selecting the draw ratio and take-off ratio conditions. The draw ratio is expressed as the ratio between the lip gap of the die and the thickness of the film sheet actually obtained.
As for this condition, sufficient orientation of the particles can be obtained by setting the draw ratio to 20 to 100.

In addition, in order to finish the surface of the film sheet to a mirror finish, the resin released from the die is pressed with a metal roll on the first cooling roll (the first cooling roll), which causes the light reflected from the pearl pigment to be diffusely reflected. Since the color returns without any movement, the colors become even more vivid and enhance the effect.

〔Example〕

Example 1 Composition Part by weight Polycarphot (manufactured by Kijin Kasei: Panlite) 1
00 bar + c Hikoit'l (Made by Me11ri:
Ilitshishi235)・・・・・・1 With the above composition, both the cylinder temperature and die temperature are 290°C.
A sheet with an extrusion thickness of 0.3 m/m was obtained under the conditions of a draw ratio of 50 and a take-off ratio of 5. This sheet appeared bright green in reflected light, and a pale red polycarbonate sheet was obtained in transmitted light.

[Effects of the Invention] According to the present invention, the reflected light has pearlescent hues of gold, red, purple, blue, and green, and the transmitted light has complementary colors of each hue, that is, purple, green, yellow, orange, and red. In order to obtain a plastic sheet that has a functional design that looks like a pastel color and has a pale overall color tone, that is, a so-called pastel color pattern, this method is suitable as a method for producing a decorative sheet that can most effectively exhibit this effect. The decorative sheet obtained according to the manufacturing method of the present invention can be used in various fields such as laminated packaging films, packaging materials for plastic cases, lampshades, blinds, and roll curtains, giving an unprecedented design and luxurious feel. Create a product display effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the decorative sheet of the present invention, and FIG. 2 is a schematic diagram showing the shape of the pearl pigment.

Claims (2)

[Claims] (1) Particles of microflake-like mica with a thickness of 0.05 to 2.0 μm coated with titanium dioxide to a film thickness in the range of 30 to 500 μm are uniformly dispersed in a transparent plastic, and A method for producing a decorative sheet, which comprises forming a film by an extrusion method under production conditions of a draw ratio of 20 to 100 in order to achieve orientation. (2) A decorative sheet according to claim 1, characterized in that in a sheet having a thickness of 0.2 mm or more, the resin discharged from a die is pressed by a metal roll onto a cooling roll that comes into contact with it first. manufacturing method.