JPH07304135A - Composite resin sheet - Google Patents

Abstract

PURPOSE:To obtain a decorating resin sheet which possesses favorable abrasion resistance and high texture and is capable of bending processing further. CONSTITUTION:A resin composition which contains at least 20wt.% inorganic powder which has Mohs hardness of at least 4, a difference in indexes of refraction of not exceeding 0.1, and an aspect ratio of particles of not exceeding 5 on the basis of the total quantity of resin and the inorganic powder and transmission factor of visible light is at least 30% is taken as the first layer and a resin composition which has a transmission factor of the visible light of at least 10% and is colored is taken as the second layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite resin sheet, particularly a composite resin sheet having a high texture and good scratch resistance, which can be preferably used for a decorative board or the like.

[0002]

2. Description of the Related Art Heretofore, compositions in which glass fibers and calcium carbonate are mixed with various transparent resins have been known. However, in the case of calcium carbonate, the surface hardness of the molded product is low and the translucency is also low. Further, in the case of glass fiber, although the light-transmitting property is high, the surface hardness of the molded product is low and it is easily scratched. Therefore, a resin sheet having high translucency and hardly scratched is not known.

On the other hand, an acrylic or silicon type hard coat is known for imparting scratch resistance. However, since this hard coat is a cross-linked resin, it cannot be heat-bent, and special equipment is required to increase the cost of the product, which is not preferable. Further, a sheet in which a pattern printing sheet is laminated on the back surface of a transparent sheet for improving the texture of the sheet is known, but the texture is insufficient, and a sheet having a deep and high texture is not known.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin sheet having good scratch resistance, high texture, and capable of being bent.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an inorganic powder having a Mohs hardness of 4 or more, a refractive index difference from a resin of 0.1 or less, and an aspect ratio of particles of 5 or less is used as a total amount of the resin and the inorganic powder. 20% by weight or more, the visible light transmittance is 30
% Or more of the resin composition as the first layer, and the visible light transmittance is 10
% Of the resin composition is provided as a second layer to provide a composite resin sheet.

The composite resin sheet of the present invention is a composite resin sheet in which a first layer having a high light-transmitting property and a high scratch resistance and a second layer having a design property are laminated. When it is used as a decorative plate, the first layer is attached to the base material with the first side facing up. First
The thickness of the layer is about 0.2 to 2 mm, and the thickness of the second layer is 0.2.
About 2 mm is suitable.

The resin composition for the first layer must have a visible light transmittance (average transmittance in the wavelength range of 400 to 800 nm) of 30% or more. When the visible light transmittance is less than 30%, the color pattern of the second layer becomes unclear, and a deep and high texture cannot be obtained. Further, in order to obtain a high texture, it is effective to add a color pattern or pattern to the first layer, but in this case as well, the visible light transmittance needs to be maintained at 30% or more.

The resin used for the first layer is not particularly limited and various resins can be used. In particular,
A transparent resin such as an acrylic resin such as a methyl methacrylate homopolymer or a copolymer thereof, a vinyl chloride resin such as a vinyl chloride homopolymer or a copolymer thereof, or an unsaturated polyester resin is preferable.

The inorganic powder used for the first layer preferably has a refractive index close to that of the resin, and the difference in refractive index must be 0.1 or less.
When the difference in refractive index exceeds 0.1, high translucency cannot be obtained, which is unsuitable. The Mohs hardness of the inorganic powder needs to be 4 or more. When the Mohs hardness is less than 4, high scratch resistance cannot be obtained, which is unsuitable.
The inorganic powder has a particle aspect ratio of 5 or less. As such an inorganic powder, silica, glass, nepheline and the like are suitable. Regarding silica, crystalline silica is particularly preferable because it has a refractive index close to that of vinyl chloride resin.

The average particle size of the inorganic powder is preferably 1 to 50 μm. If the average particle size is less than 1 μm, the viscosity becomes high especially in the case of a highly filled composition, molding becomes difficult, and the translucency may decrease, which is not preferable. When the average particle size exceeds 50 μm,
It is not preferable because mechanical strength, especially impact strength, is lowered.

The blending ratio of the resin and the inorganic powder needs to be 20% by weight of the inorganic powder with respect to the total amount of the resin and the inorganic powder. When the content of the inorganic powder is less than 20%, sufficient scratch resistance cannot be imparted, which is unsuitable. The blending ratio of the inorganic powder is preferably 70% by weight or less. If the inorganic powder exceeds 70% by weight, molding becomes difficult,
In addition, both strength and translucency may decrease, which is not preferable. If necessary, a heat stabilizer, a plasticizer, a lubricant, an ultraviolet absorber and the like can be added to this resin composition.

The second layer is a resin sheet having a color pattern and a pattern, and the visible light transmittance needs to be 10% or more. If it is 10% or less, a deep and high-quality texture cannot be obtained. The same resin as the first layer can be used as the resin. If necessary, a filler such as an inorganic powder, a heat stabilizer, a plasticizer, a lubricant, an ultraviolet absorber, or the like can be optionally added to the second layer.

[0013]

In the present invention, a hard inorganic powder having a refractive index close to that of the resin is used for the surface layer, whereby high scratch resistance and translucency can be obtained. A high-quality texture can be obtained by combining the lower layer with the color pattern and the surface layer. This is due to the translucency of the surface layer and the light diffusivity of the inorganic powder. By adding a color pattern to the surface layer, the color pattern overlaps with the color pattern in the lower layer, and a higher texture can be obtained.

[0014]

【Example】

Example 8% by weight of ethylene having a refractive index of 1.54 Copolymerized vinyl chloride 1
To 100 parts, 100 parts of glass powder having an average particle size of 25 μm and a refractive index of 1.55, dibutyltin mercaptide 2
Parts and 0.5 parts of green colored mica particles are kneaded at 170 ° C. in a Labo Plastomill, and then press-formed to a thickness of 1 mm.
Sheet was molded. The visible light transmittance of this sheet is 50
%Met. This sheet is the first layer.

On the other hand, 8% by weight of ethylene having a refractive index of 1.54
After kneading 100 parts of copolymerized vinyl chloride with 50 parts of glass fiber having a diameter of 10 μm and an average length of 3 mm, 2 parts of dibutyltin mercaptide and 0.05 parts of a pink pigment at 170 ° C. in a Labo Plastomill, A sheet having a thickness of 1 mm was formed by press molding. The visible light transmittance of this sheet was 20%. This sheet is the second layer.

The first layer and the second layer were laminated by pressing to obtain a composite resin sheet. This sheet was a patterned sheet with a sense of transparency and depth. Regarding the surface of the first layer side, in the scratch resistance test with steel wool (10 reciprocations under a load of 200 g / cm ² ), there was no deterioration in gloss due to scratches.

Comparative Example A first layer was obtained by molding in the same manner as in Example except that magnesium hydroxide (refractive index: 1.56, average particle size: 20 μm) was used as the inorganic powder of the first layer. The visible light transmittance of this sheet was 10%. A composite resin sheet was obtained by laminating the second layer of the example. Since this sheet lacked transparency, it had no depth and texture. In addition, the surface of the first layer had a decreased gloss in the steel wool test.

[0018]

EFFECTS OF THE INVENTION The composite resin sheet of the present invention has good scratch resistance and has a deep and high texture due to the combination of the first layer having a high light-transmitting property and the second layer having a color pattern. When the color pattern is also applied to the first layer, the color pattern overlaps with the color pattern of the second layer, and a higher texture can be obtained. Also, unlike the conventional hard-coated resin sheet, it can be bent.

Claims (3)

[Claims] 1. An inorganic powder having a Mohs hardness of 4 or more, a refractive index difference with a resin of 0.1 or less, and an aspect ratio of particles of 5 or less is contained in an amount of 20% by weight or more based on the total amount of the resin and the inorganic powder. A composite resin sheet having a resin composition having a visible light transmittance of 30% or more as a first layer and a colored resin composition having a visible light transmittance of 10% or more as a second layer. 2. The composite resin sheet according to claim 1, wherein the resin of the first layer is an acrylic resin, a vinyl chloride resin or an unsaturated polyester resin. 3. The composite resin sheet according to claim 1, wherein the inorganic powder is silica, glass or nepheline.