JPH0632973A - Light-scattering polycarbonate resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. high in light transmittance and excellent in light-scattering properties, heat resistance, mechanical characteristics, flame- retardance, etc., by compounding a polycarbonate resin with a specified amt. of a specific acrylic resin. CONSTITUTION:100 pts.wt. polycarbonate resin (e.g. Upilon E-2000F, a product of Mitsubishi Gas Chemical Co., Inc.) is compounded with 1-30 pts.wt. crosslinked acrylic resin beads which have a mean particle diameter of 1-20mum and are obtd. by the suspension polymn. of a monomer mixture comprising 100 pts.wt. noncrosslinking monomer component consisting of 50-100wt.% acrylic monomer, 0-50wt.% arom. vinyl monomer, and 0-20wt.% other vinyl monomers (e.g. methyl methacrylate) and 0.5-10 pts.wt. crosslinking monomer (e.g. allyl methacrylate).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light diffusing polycarbonate resin composition having a high light diffusing property and a high light transmittance. The light-diffusing polycarbonate resin molded body obtained by using the composition of the present invention makes the image of the light source provided behind it invisible regardless of blinking, and makes the light emitted from the light source have a uniform brightness. Since it is diffused and transmitted through, it is preferably used for protective applications such as signboards, illuminators, and indicator lights, and optical applications such as liquid crystal backlight diffuser plates and display panels.

[0002]

2. Description of the Related Art Conventionally, an acrylic resin has been used as a base resin for a light diffusing plate, but recently, due to diversifying market needs, improvement in heat resistance, mechanical properties, flame retardancy, etc. and weight reduction have been achieved. Is desired. As means for imparting light diffusion performance,
A general method is to disperse an inorganic filler such as glass fiber, barium sulfate, titanium oxide, or talc in the base resin, or mechanically emboss the surface with a processing machine such as an embossing roll.

However, when the inorganic filler is added, there are problems that the light transmittance is generally remarkably reduced, and the molecular weight is reduced and the coloring is caused by the hydrolysis of the polycarbonate resin. In particular, when glass fibers are used, the glass fibers may be oriented in the resin flow direction during molding, or the glass fibers may float on the surface of the molded product, impairing the appearance. Further, the glass fibers wear the cylinders and screws of the molding machine during molding. on the other hand,
Although a mechanical method can obtain a molded article having a light diffusing effect to some extent, it has a drawback that surface irregularity is lost when the secondary processing is performed and the light diffusing property is reduced.

[0004]

The object of the present invention is to solve the above-mentioned problems in the prior art, to provide uniform and excellent light diffusivity and high light transmittance, heat resistance, mechanical properties and difficulty. An object of the present invention is to provide a resin composition for light diffusion and transmission, which has excellent flammability, can be formed into a film, and does not lose its light diffusion property even after secondary processing.

[0005]

Means for Solving the Problems As a result of intensive studies on the light diffusing polycarbonate resin composition, the inventors have found that
Focusing on the transparency of the acrylic resin and the difference in the refractive index between the two resins, the acrylic resin having a bead-like crosslinked structure is blended with the polycarbonate resin, and the above-mentioned problems can be solved by molding the resin composition. They found things and reached the present invention. That is, in the present invention, 100 parts by weight of the polycarbonate resin (A) is mixed with 100 parts by weight of the non-crosslinking monomer (a) containing 0.5 to 10 parts by weight of the crosslinking monomer (b). The present invention relates to a light diffusing polycarbonate resin composition obtained by blending 1 to 30 parts by weight of a bead-shaped crosslinked acrylic resin (B) having a particle diameter of 1 to 20 μm obtained by turbid polymerization. (A) Non-crosslinkable monomer Acrylic monomer 50 to 100% by weight Aromatic vinyl monomer 0 to 50% by weight Other vinyl monomer 0 to 20% by weight

The polycarbonate resin (A) used in the present invention is produced by reacting an aromatic dihydroxy compound with phosgene or a carbonic acid diester by a melting method or a solution method. As typical examples of aromatic dihydroxy compounds, 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A), 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4- Hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) sulfidebis Examples thereof include (4-hydroxyphenyl) sulfone, and among these, bisphenol A is particularly preferable.

The bead-shaped crosslinked acrylic resin (B) used in the present invention contains 0.5 to 1 of (b) the crosslinking monomer in 100 parts by weight of the non-crosslinkable monomer (a) consisting of the following components.
It is obtained by suspension polymerization of 0 part by weight. The above-mentioned (a) non-crosslinkable monomer is a mixture of the following components as follows. Acrylic monomer 50-100% by weight Aromatic vinyl monomer 0-50% by weight Other vinyl monomer 0-20% by weight

As the acrylic monomer, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethyl-hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, etc. may be used alone or in combination. However, methylmethacrylate is particularly preferable.

The above-mentioned aromatic vinyl monomer can be used in a range not exceeding 50% by weight in the non-crosslinking monomer, and specific examples thereof include styrene, α-methylstyrene and vinyltoluene. When it exceeds 50% by weight, the light diffusing effect cannot be expected because it is close to the refractive index of the polycarbonate resin.

The above-mentioned other vinyl monomers may not be particularly used, but they can be used in a range not exceeding 20% by weight in the non-crosslinking monomer. Specifically, fumaric acid, maleic acid and the like are used together. Polymerizable carboxylic acid and its ester can be illustrated.

As the (b) crosslinkable monomer used in the present invention, a compound having two or more unsaturated bonds in the molecule is used. Particularly, at least one of the two or more unsaturated bonds is used. Having an allyl group is desirable. Examples of the crosslinkable monomer (b) include allyl methacrylate, triallyl cyanurate, triallyl isocyanate, ethylene glycol dimethacrylate, propylene glycol diallyl ether, divinylbenzene, diethylene glycol dimethacrylate, and 1,6-hexanebiol dimethacrylate. .

The amount of the crosslinkable monomer added is 0.5 to 10 per 100 parts by weight of the total amount of the non-crosslinkable monomers.
Parts by weight, preferably 1 to 5 parts by weight. Is. If the amount is less than 0.5 part by weight, the heat resistance of the obtained beads is low due to incomplete crosslinking, and the beads may be deformed after molding. On the other hand, if the amount exceeds 20 parts by weight, the light diffusion effect is not particularly promoted, which is economically disadvantageous.

The bead-shaped crosslinked acrylic resin (B) used in the present invention is produced by a conventional suspension polymerization method by blending the non-crosslinking monomer (a) and the crosslinking monomer (b) in a fixed ratio. In the present invention, the average particle size of the crosslinked polymer is preferably 1 to 20 μm. The average particle size is 20 μm above
When the average particle size is less than 1 μm, a sufficient light diffusion effect cannot be obtained. Further, it is particularly desirable that 80% or more of the particle diameter of the cross-linked polymer is within the above range of 1 to 20 μm.

The crosslinked acrylic resin is blended as a base resin in an amount of 1 to 30 parts by weight based on 100 parts by weight of the polycarbonate resin. If the blending ratio of the crosslinked acrylic resin is less than 1 part by weight, a sufficient light diffusion effect cannot be obtained, while if it is blended in excess of 30 parts by weight, it does not particularly improve the light diffusing performance. Transmittance, appearance,
Inconvenience occurs due to deterioration of physical properties, economy, etc.

The light-diffusing resin composition of the present invention may be mixed with various additives such as flame retardant, stabilizer, pigment, dye, aggregate, fiber reinforced material, etc. within a range that does not impair the object of the present invention. can do. In preparing the light diffusing resin composition of the present invention, a conventionally known method may be adopted, and a method of kneading with an extruder, a Banbury mixer, a roll or the like is appropriately selected.

[0016]

EXAMPLES The present invention will be described in detail with reference to examples. The following methods were adopted for the measurement of each physical property value. 1) Total light transmittance, haze value Measured by a haze meter manufactured by Nippon Denshoku Industries Co., Ltd. 2) Diffusivity Measured by a transmission method using an automatic goniophotometer manufactured by Murakami Color Research Laboratory Co., Ltd. Diffusivity (%) = (100) x (20 ° brightness value + 70 ° brightness value) / (5
Luminance value x 2) 3) Dispersion Dispersion: When the amount of transmitted light when γ = 0 ° (linear direction) is 100 when light is applied to the sample, γ when the transmitted light amount becomes 50 Angle (angle with linear direction).

Example 1 100 parts by weight of a polycarbonate resin (trade name: Iupilon E-2000F, manufactured by Mitsubishi Gas Chemical Co., Inc.),
As a light diffusing agent, 5 parts by weight of a crosslinked acrylic resin (MR-13G, manufactured by Soken Chemical Industry Co., Ltd.) having an average particle diameter of 13 μm was mixed and stirred with a mixer, and the mixture was extruded through a T-die with a vent extruder, and the thickness was three rolls. It was processed into a 1.0 mm extruded plate. This extruded plate has a total light transmittance of 80% and a haze value of 92.
%, The diffusivity was 46%, and the dispersity was 28 °. Also,
A light source was placed behind the molded product and the light diffusion property was visually observed, but no image of the light source was observed. The evaluation results are summarized in Table 1.

Example 2 An extruded plate was obtained in the same manner as in Example 1 except that 0.3 part by weight of titanium oxide was further added as a pigment to the resin composition of Example 1. The extruded plate had a total light transmittance of 66%, a haze value of 92%, a diffusivity of 57%, and a dispersity of 32 °. The surface condition of the extruded plate was the same as that of the extruded plate of Example 1, and a good opalescent plate was obtained. The evaluation results are summarized in Table 1.

Comparative Example 1 As a light diffusing agent, the fiber diameter was 10 μm and the fiber length was 100 to 200.
An extruded plate was prepared in the same manner as in Example 1 except that 15 parts by weight of short glass fiber having a diameter of μm and 0.3 part by weight of titanium oxide were used as a pigment. The extruded plate had a total light transmittance of 57%, a haze value of 92%, a diffusivity of 39%, and a dispersity of 19 °, even though glass short fibers corresponding to three times the amount of the crosslinked acrylic resin were added. The light diffusion was poor. Further, the surface condition of the extruded plate showed irregularities due to the glass fiber. The evaluation results are summarized in Table 1.

[0020]

[Table 1] Total light transmittance Haze value Diffusivity Dispersity Plate thickness excess rate (%) (%) (%) (°) (mm) Example 1 80 92 46 28 28 1.0 Example 2 66 92 57 32 32 1.0 Comparative example 1 57 92 39 19 1.0

[0021]

The effects of the present invention are listed below. (1) A high light transmittance and a uniform and excellent light diffusing performance can be obtained by adding a smaller amount of diffusing agent than the conventional method. (2) No reduction in molecular weight or coloring due to hydrolysis of the polycarbonate resin. (3) The molding process can be performed in substantially the same manner as the case of using the polycarbonate resin alone. (4) The wear of the cylinder and the screw of the molding machine is reduced.

 ─────────────────────────────────────────────────── --Continued front page (72) Inventor Shoichi Inoue 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa Sanryo Gas Chemical Co., Ltd. Plastics Center

Claims (1)

[Claims] 1. A non-crosslinking monomer (a) comprising the following components per 100 parts by weight of a polycarbonate resin (A).
An average particle size of 1 to 20 μm obtained by suspension polymerization of 100 parts by weight of 0.5 to 10 parts by weight of the crosslinking monomer (b).
A light-diffusing polycarbonate resin composition obtained by mixing 1 to 30 parts by weight of the bead-shaped crosslinked acrylic resin (B) of m. (A) Blending ratio of non-crosslinkable monomer Acrylic monomer 50 to 100% by weight Aromatic vinyl monomer 0 to 50% by weight Other vinyl monomer 0 to 20% by weight