JPS61221255A - Acrylic resin sheet having fine uneven surface - Google Patents

Abstract

PURPOSE:To provide the titled resin sheet having excellent glare protection effect, illuminating effect and energy efficiency and suitable for use as an illuminating cover, consisting of a methyl methacrylate polymer and fine white carbon powder and fine BaSO4 powder and/or fine CaCO3 powder. CONSTITUTION:0.5-5.0pts. fine white carbon powder having a particle size of 0.5-20mu, such as hydrated amorphous silica (SiO2.nH2O), and 0.5-5.0pts. fine BeSO4 powder having a particle size of 1-6mu and/or fine CaCO3 powder having a particle size of 0.5-20mu are mixed with 100pts. methyl methacrylate (co)polymer having a methyl methacrylate content of 100-85% and an MW of 50,000-500,000 in a Henschel mixer with stirring. The mixture is kneaded in a single-srew extruder having a kneading mechanism and passed between roller having a fine uneven surface to form a sheet having an uneven pattern on the surface thereof, thus obtaining the titled resin sheet whose surface has recesses and protrusions at intervals of 40-200mu.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an acrylic resin plate, particularly an acrylic resin plate with a matte surface and excellent anti-glare effect suitable for uses such as lighting covers.

(Prior Art and Problems) Methyl methacrylate polymers are used as plate-shaped products for signboards, displays, lighting covers, and the like. In particular, plate-shaped products such as so-called translucent laminated plates are often used for lighting covers after undergoing secondary heat processing such as press processing and vacuum processing, increasing the lighting/opening ratio in interiors and cars. Recently, its use has become very popular due to its anti-glare and anti-glare effects.◇The key to the performance of a lighting cover made of acrylic resin laminated translucent board is that the light source cannot be seen through it and the surface is like frosted glass. It has a matte and soft lighting effect, has an ``anti-glare effect'' that is excellent for eye health, has a high total light transmittance, has an excellent energy effect, and is also beautiful. .

Conventionally, an inorganic substance such as barium sulfate has been used as a light diffusing agent to obtain a translucent emulsion plate, but only a glossy surface can be obtained. As a method for removing gloss from the surface, a method is used to make the surface of a plate-shaped product matte by using a matte roll having a surface with fine irregularities as a forming roll to add fine irregularities to the surface of the plate-shaped product. but,
These methods have the disadvantage that in order to prevent the light source from being seen through, it is necessary to add a suitable amount of light diffusing agent, which inevitably reduces the total light transmittance.

(Means for Solving the Problems) Therefore, as a result of intensive research into a technology that eliminates the "transparency" of the light source and minimizes the decrease in total light transmittance, the present inventors developed a methyl methacrylate polymer. A white carbon fine powder, a calcium carbonate fine powder and/or a barium sulfate fine powder are blended into the mixture, and after cross-extrusion, the product is formed using a roll having a finely uneven surface to form a plate-like product with an uneven surface. The present invention was completed by discovering that it is possible by doing this.

That is, the present invention is a methyl methacrylate polymer Zo.

0 parts of white carbon fine powder and 0.5 to 5.0 parts of calcium carbonate fine powder and/or barium sulfate fine powder, and the surface unevenness interval is 40 to 200μ. It is an acrylic resin board.

The acrylic resin plate of the present invention is an acrylic resin plate in which the light source cannot be seen through, the surface is matte, the "anti-glare effect" is high, the total light transmittance is high, and the energy effect is excellent.

The methyl methacrylate polymer referred to in the present invention is
It contains a copolymer or homopolymer containing 85 or more methyl methacrylates, and there is no problem in containing a trace amount of additives such as an ultraviolet LSA absorber, a fluorescent brightener, and a heat stabilizer. Although the molecular weight is not particularly limited in the present invention, it is generally from 50,000 to 500,000, preferably from 70,000 to 300,000, from the viewpoint of ease of crosstalk and physical properties.

The white carbon fine powder used in the present invention is a fine powder of hydrated amorphous silica (SiOl.nH2O), and its particle size is usually 0.5 to 20 μm, preferably 0.5 to 10 μm.

Calcium carbonate used in the present invention usually has a particle size of 0.5
It is between 1 and 20μ, preferably between 1 and 10μ. Valicum sulfate used in the present invention usually has a particle size of 1 to 6 μm,
The blending amount of the white carbon fine powder, which is preferably 2 to 4μ, varies depending on the intended use, but in order to obtain good optical properties and beauty, it is preferably 0.5 parts to 5.0 parts. If it is less than the required 0.5 parts, the energy efficiency for the anti-glare effect is not good;
．． If it exceeds 0 parts, whitening will be reduced and beauty will be lost. The amount of calcium carbonate fine powder and barium sulfate fine powder varies depending on the intended use, but in order to obtain good optical properties and beauty,
0.5 parts to 5.0 parts are required. If it is less than 0.5 part, the transparency will be impaired, that is, the anti-glare effect will be impaired.

Moreover, if it exceeds 5.0 parts, the total light transmittance will decrease and energy efficiency will be impaired.

The method for manufacturing the acrylic resin plate of the present invention includes stirring and mixing with a Henschel mixer, for example, and using a single-screen extruder with a cross-wire mechanism, at a resin temperature of 200 to 300.
A mixture of methyl methacrylate polymer, white carbon fine powder, calcium carbonate fine powder and/or variecum sulfate is prepared at a temperature of approximately The surface of the shaped product is given an uneven shape and cooled to form a plate shaped product. The interval between the unevenness on the surface of the plate-shaped product must be 40 to 200μ,
When it is less than 40μ or more than 200μ, the energy efficiency for anti-glare effect decreases.

The interval between surface irregularities referred to here is JIS B12O.
3 "Definition and Display of Surface Roughness" 6 Average interval of unevenness (Sm)" shown in the explanation, and is calculated by the following formula.

No. Smi Sm1S (Example) Specific examples of the present invention will be described below.0 Example 1 Beads of methyl methacrylate copolymer (molecular weight 180,000) containing methyl acrylate tSS1. G 0 part, white carbon fine powder O, S part with an average particle size of 2μ, 3
．． 0 parts, 5.0 parts, and 1.0 parts, 2.5 parts, and 40.0 parts of calcium carbonate fine powder with an average particle size of 5 μ, respectively, and barium sulfate fine powder with an average particle size of 3 μ, respectively. 1.0 parts, 2.5 parts, and 4.0 parts of 1.0 parts, 2.5 parts, and 4.0 parts of powder, and 0 parts of calcium carbonate fine powder with an average particle size of 5 μ and 0 part of parinium sulfate fine powder with an average particle size of 3 μ.
．． The mixtures of 5 parts and 0.5 parts, 1.25 parts and 1.25 parts, and 2.0 parts and 2.0 parts were stirred and mixed using a Henschel mixer, and then a single screw with a cross-wire extrusion mechanism (90Mφ , bent type) to knead the width xoo
After extruding the resin into a plate shape using an osa T-type die at a resin temperature of 260°C, the roll 2 with a smooth surface and the satin-finished rolls 3 and 4 having fine irregularities on the surface (the size of the irregularities are the same) as shown in Fig. Using a combination of three rolls, a thickness of 20. A plate-shaped product with a width of 1000 am was produced.

The total light transmittance of the plate-shaped product was measured using an integrating sphere light transmittance measuring device in accordance with JIS K-7105. In addition, the "transparency" of the light source was measured using the method and apparatus shown in Figure 2, and the distance between the light source and the sample was varied, and the luminance difference between the center part of the sample and the light source part was measured.
It is expressed as the distance between the light source and the sample that becomes 0 nt or less.

Furthermore, the spacing between the unevenness on the surface of the plate was measured using a surface roughness measuring machine manufactured by Tokyo Seimitsu ■, and @Sm'' was calculated.The results are shown in Table 1.

Example 2 A plate-shaped product was molded in the same manner as in Example 1, except that 3.0 parts of white carbon fine powder was used and a matte roll with different surface roughness was used, and the same measurements as in Example 1 were carried out. I did this. The results are shown in Table 1.0 Comparative Example 1 White carbon fine powder was 0 parts and 3 parts, Figure 1 (6)
A plate-shaped product was molded in the same manner as in Example 1, except that three rolls of P-Role with a smooth surface were used, and the same measurements as in Example 1 were carried out. The result is the second
Shown in the table.

Comparative Example 2 A plate-shaped product was heated in the same manner as in Example 1, except that the white carbon fine powder was 0 parts, and the same measurements as in Example 1 were performed. The results are shown in Table 2.

Comparative Examples 3 and 4 Example 1 and 4 except that 3.0 parts of white carbon fine powder and satin-finished four-colors (same as those used in Example 2) with different surface roughness were used. A plate-shaped product was prepared in the same manner, and the same measurements as in Example 1 were performed. The results are shown in Table 2.

Examples (1) (2) and comparative examples (1) (2) (3)
In Table (1) and Table (2) of the results of (4), "total light transmittance (energy efficiency)" and "transparency (anti-glare effect)"
” is shown in Figure 3.

As is clear from Figure 3, comparative examples (1) (2) (
3) Compared to the conventional plate-shaped product shown in (4), the white carbon fine powder of the present invention, barium sulfate fine powder, and calcium carbonate fine powder are blended, and the surface becomes finely uneven after cross-wire extrusion. A plate-shaped product formed using a roll and having fine irregularities on its bare surface has a high ``total light transmittance'' compared to ``transparency.'' That is, it has excellent "anti-glare effect" and excellent "energy efficiency."

Further, the plate-shaped product of the present invention has a matte surface and a soft lighting effect, which is good for eye health, and has very useful performance as a lighting cover and the like.

Below margin

[Brief explanation of drawings]

FIG. 1 (4) is a sectional view of the molding machine used in Example 1. 1) is a sectional view of the molding machine used in Comparative Example 1. In FIG. 1, 1 is a T-shaped die, 2 is a roll with a smooth surface, 3 and 4 are rolls with finely uneven surfaces, and 5 is a plate-shaped product. FIG. 2 (4) is a side view of a method for measuring the "transparency" of a plate-shaped product. Figure 2 CB) (A) is a front view of the device for measuring the "transparency" of plate-shaped products, and Figure 2 ω) @) is a surface measurement view of the device shown in )0) in Figure 2. It is. In Figure 2; 10 is a light source enclosure box, 11 is a cylindrical fluorescent light source, 12 is a sample, 1
3 indicates a luminance meter. Figure 3 shows the first results of Example 1.2 and Comparative Examples 1 to 4.
．． It is a correlation diagram between "total light transmittance (energy efficiency)" and "transparency (anti-glare effect)" in Table 2. Patent applicant: Asahi Kasei Industries, Ltd. Figure 1 (A) (B) Figure 2 (A) (B) 31st! I 2 vertical + j marks (mm) (large - gate pay study)

Claims (1)

[Claims] 0.5 to 5.0 parts of white carbon fine powder and 0.5 to 5 parts of barium sulfate fine powder and/or calcium carbonate fine powder per 100 parts of methyl methacrylate polymer.
．． 0 part, and the distance between the unevenness on the surface is 40 to 200
μ acrylic resin plate