JPH0539400A - Acrylic resin plate - Google Patents

Abstract

PURPOSE:To obtain an acrylic resin plate excellent in glare shielding effect by mixing a methyl methacrylate polymer with a fine talc powder and a fine barium sulfate powder each in a specified amount and forming the mixture so as to give surface irregularities at specified intervals. CONSTITUTION:100 pts. methyl methacrylate polymer is mixed with 0.5-7 pts. fine talc powder and 0.5-5 pts. fine barium sulfate powder and/or fine calcium carbonate powder by stirring in, e.g. a Henschel mixer. The mixture is fed to rolls having fine surface irregularities to form a plate provided with surface irregularities at intervals of 40-200mum, thus producing acrylic resin plate. By this technique, an acrylic resin plate through which a light source is not visible and which has a matte side with an excellent glare shielding effect, has high total light transmittance, and is excellent in energy effect can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic resin plate, particularly a matte surface acrylic resin plate having an excellent antiglare effect, which is suitable for applications such as lighting covers.

[0002]

2. Description of the Related Art Methyl methacrylate polymer is used as a plate-shaped product for signboards, displays, lighting covers and the like. Among them, so-called opalescent semi-transparent plate products are often used after secondary heat processing such as press working and vacuum working for the purpose of lighting covers, which increases the lighting efficiency in the interior and interior of vehicles and prevents them. Due to the glare effect, its use has become very popular recently. The point of performance that should be considered when using an acrylic resin milky color semi-transparent plate for a lighting cover is a lighting effect that the surface is frosted and soft like a frosted glass because the light source cannot be seen through, that is, eye health. It has an excellent “anti-glare effect”, a large total light transmittance, an excellent energy effect, and excellent beauty.

Conventionally, in order to obtain a milky semitransparent plate, an inorganic substance such as barium sulfate was used as a light diffusing agent, but only a glossy surface was obtained. Further, as a method of delustering the surface, a method of making the surface of the plate-like product finely uneven by using a matte roll having a finely uneven surface on the forming roll is used. It was

[0004]

However, in these methods, it is necessary to add a considerable amount of a light diffusing agent so that the light source cannot be seen through, and as a result, the total light transmittance is inevitably small. There was a problem that it would end up.

[0005]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a technique for eliminating the “translucency” of a light source and minimizing the reduction of the total light transmittance, and as a result, talc was added to a methyl methacrylate polymer. Fine powder and calcium carbonate fine powder and / or barium sulfate fine powder are blended, kneaded and extruded, and then molded using a roll with fine irregularities on the surface to give irregularities to the surface of the plate-like product That is, the present invention has been completed.

That is, the present invention relates to (1) 0.5 to 7 parts of talc fine powder (2) 0.5 to 5 parts of calcium carbonate fine powder and / or barium sulfate fine powder to 100 parts of methyl methacrylate polymer. And an acrylic resin plate having a surface unevenness of 40 to 200 μm. INDUSTRIAL APPLICABILITY 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, has an “antiglare effect”, has a large total light transmittance, and has an excellent energy effect.

The present invention will be described in detail below. The methyl methacrylate methyl polymer referred to in the present invention includes a copolymer or homopolymer containing 85% or more of methyl methacrylate, to which a trace amount of additives such as an ultraviolet absorber, a brightening agent and a heat stabilizer is added. It does not matter to include it. The molecular weight is not particularly limited in the present invention, but is generally 50,000 to 500,000, preferably 70,000 to 300,000 in view of easiness of kneading and physical properties.

The talc fine powder used in the present invention is a fine powder obtained by mechanically crushing a plate-shaped crystal talc rough containing naturally-occurring magnesium silicate as a product, and its particle size is 1 to 10 μm. It is preferably 3 to 7 μ. The calcium carbonate used in the present invention usually has a particle size of 0.5 to 20 μm.
And preferably 1 to 10 μm. The barium sulphate used in the present invention usually has a particle size of 1 to 6 μm, preferably 2
~ 4μ.

The blending amount of the talc fine powder varies depending on the intended use, but 0.5 to 7 parts are required to obtain good optical characteristics and beauty. If it is less than 0.5 part, the energy efficiency for antiglare effect is not good, and if it exceeds 7 parts, the whiteness is lowered and the beauty is deteriorated. The amount of calcium carbonate fine powder and / or barium sulfate fine powder mixed varies depending on the intended use, but in order to obtain good optical characteristics and beauty, it is 0.5
Parts to 5 parts are required. If it is less than 0.5 part, the transparency is impaired, that is, the antiglare effect is impaired. On the other hand, if it exceeds 5 parts, the total light transmittance is lowered and the energy efficiency is impaired.

In the method for producing an acrylic resin plate of the present invention, for example, a Henschel mixer is used for stirring and mixing, and a single screw type extruder with a kneading mechanism is used to obtain a resin temperature of 20.
At a temperature of about 0 to 300 ° C, a mixture of (1) methyl methacrylate polymer, (2) talc fine powder, (3) calcium carbonate fine powder and / or barium sulfate is prepared,
Next, the compound is made into a plate-like product by applying an unevenness to the surface of the plate-like product by using a roll having a fine unevenness on the surface and cooling. The unevenness of the surface of the plate product is 40 to 20.
It needs to be 0 μ, and if it is less than 40 μ or exceeds 200 μ, the energy efficiency for the antiglare effect decreases.

As used herein, the interval between surface irregularities is JI.
S B0601 “Average roughness interval (Sm) of irregularities” shown in the explanation of “Definition and display of surface roughness” and is represented by the following formula.

[0012]

[Equation 1]

[0013]

EXAMPLES Specific examples of the present invention will be described below.

[0014]

Example 1 100 parts of beads of a methyl methacrylate copolymer (molecular weight 180,000) containing 95% of methyl methacrylate and 5% of methyl acrylate was used, and the average particle size was 4
0.5 parts of talc fine powder of μ, 3.0 parts of 7.0 parts and 1.0 part of calcium carbonate fine powder of average particle size 5 μ, respectively.
Parts, 2.5 parts, 4.0 parts, and 1.0 part of fine barium sulfate fine powder having an average particle size of 3μ, respectively.
A mixture of 2.5 parts and 4.0 parts, and calcium carbonate fine powder having an average particle size of 5μ and an average particle size of 3μ, respectively.
0.5 parts and 0.5 parts of fine powder of barium sulfate of 1.2,
Mixing 5 parts and 1.25 parts, 2.0 parts and 2.0 parts by stirring with a Henschel mixer, and then kneading with a single screw with a kneading extrusion mechanism (90 mmφ, pent type) and width After being extruded into a plate shape at a resin temperature of 260 ° C. by a 1000 mm T-type die, a combination of the surface smoothing roll 2 shown in FIG. 1 and the satin finish rolls 3 and 4 having the fine irregularities on the surface (the sizes of the irregularities are the same) A plate-like product having a thickness of 2 mm and a width of 1000 mm was molded by using the three rolls.

The total light transmittance of the plate-like product was measured by an integrating sphere light transmittance measuring device in accordance with JIS K-7105. In addition, the "translucency" of the light source was changed by the device shown in FIG. 2 with various distances between the light source and the sample, and the brightness of the central part of the sample and the brightness of the light source part were measured.
It is represented by the distance (mm) between the light source and the sample, which is 00 nt or less. Further, the interval between the irregularities on the surface of the plate was measured by a surface roughness measuring device manufactured by Tokyo Seimitsu Co., Ltd., and “Sm” was calculated. The results are shown in Table 1.

[0016]

[Example 2] Example 1 except that 3.0 parts of fine talc powder and a satin roll having different surface roughness were used.
A plate-shaped product was molded in the same manner as in, and the same measurement as in Example 1 was performed. The results are shown in Table 1.

[0017]

[Comparative Example 1] A plate-like product was molded in the same manner as in Example 1 except that three rolls having 0 and 3.0 parts of talc fine powder and a smooth surface shown in FIG. 3 were used. Example 1
The same measurement was performed. The results are shown in Table 2.

[0018]

Comparative Example 2 A plate-like product was molded in the same manner as in Example 1 except that the talc fine powder was 0 parts, and the same measurement as in Example 1 was performed. The results are shown in Table 2.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Comparative Examples 3 and 4] Same as Example 1 except that 3.0 parts of talc fine powder and a satin roll (same as that used in Example 2) having different surface roughness are used. Then, a plate-shaped product was molded and the same measurement as in Example 1 was performed. The results are shown in Table 2. The correlation between "total light transmittance (energy efficiency)" and "transparency (antiglare effect)" in Tables 1 and 2 of the results of Examples 1 and 2 and Comparative Examples 1, 2, 3, and 4 is shown. As shown in FIG.

As is apparent from FIG. 3, Comparative Examples 1, 2,
Compared with the conventional plate-shaped products shown in 3 and 4, the talc fine powder and the barium sulfate fine powder and / or calcium carbonate fine powder of the present invention are blended, kneaded and extruded, and then molded with a roll having a fine surface. The plate-shaped product with fine irregularities on the surface is "total light transmittance" against "transparency".
Is big. That is, it can be seen that the "antiglare effect" is excellent and the "energy efficiency" is excellent.

[0023]

The surface matte acrylic resin plate of the present invention is
Compared to conventional products, the total light transmittance is higher than that of conventional products.
It is excellent in so-called anti-glare effect and also excellent in energy efficiency. Furthermore, the acrylic resin plate-like product of the present invention has a matte surface, has a soft-feeling lighting effect, is good for eye protection, and has a very useful performance for a lighting cover and the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a molding machine used in Example 1 of the present invention.

FIG. 2 is a side view of a method for measuring the “translucency” of the plate-shaped product of the present invention.

FIG. 3 is a cross-sectional view of a molding machine used in Comparative Example 1 of the present invention.

FIG. 4 is a correlation diagram between “total light transmittance (energy efficiency)” and “transparency (antiglare effect)” of Examples 1 and 2 of the present invention and Comparative Examples 1 to 4.

[Explanation of symbols]

 1 T-type die 2 Surface smooth roll 3,4 Surface fine uneven roll 5 Plate product

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Claims (1)

[Claims] 1. To 100 parts of a methyl methacrylate polymer, 0.5 to 7 parts of (1) talc fine powder, (2) barium sulfate fine powder and / or calcium carbonate fine powder 0.1.
Includes 5 to 5 parts and has a surface irregularity interval of 40 to 200
An acrylic resin plate that is μ.