JP3447156B2 - Polycarbonate resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polycarbonate resin composition having a transmitted light hue similar to that of a polymethylmethacrylate opalescent plate containing a titanium oxide composition containing a trace amount of a polyhydric alcohol.

[0002]

2. Description of the Related Art Polycarbonate resins, which are excellent in transparency, heat resistance and impact resistance, are used in various fields such as vehicles, light electric appliances and household products. When used as a milky board for a signboard or a signboard, a transmitted light color similar to that of an existing milky board, polymethylmethacrylate milky board, is required.

As a method for obtaining a milky white and translucent material based on a polycarbonate resin, a combination of calcium carbonate and titanium oxide has already been used (Japanese Patent Publication No. 57-2481).
6) or a combination of calcium carbonate and zinc sulfide (JP-A-4-2)
58662) and the like are known. However, lighting lamp covers and signboard opacifiers made of these polycarbonate resin compositions have a drawback that transmitted light is reddish as compared with those made of polymethylmethacrylate resin.

[0004]

Means for Solving the Problems The inventors of the present invention have made it possible to transmit a polycarbonate resin without sacrificing excellent transparency, mechanical strength, and light diffusivity of a light diffusing filler, which are inherent features of the polycarbonate resin. As a result of diligent research on a material having an improved color tone of light, in a polycarbonate resin composition containing a light diffusing filler, by using a titanium oxide composition containing a trace amount of a polyhydric alcohol, polymethylmetha The present invention has been completed by finding that a polycarbonate resin composition having a transmitted light hue similar to that of an acrylate opalescent plate can be produced.

That is, the present invention uses 100 parts by weight of the polycarbonate resin (A) and 0.01 to 100 parts of the light diffusing filler (B).
5 parts by weight, and titanium oxide composition (C) 0.0001-
In a polycarbonate resin composition consisting of 5 parts by weight, the titanium oxide composition (C) comprises titanium oxide and polyhydric alcohols, and the polyhydric alcohol is 0.0
A titanium resin composition (C) containing 001 to 0.05% by weight is used, and a polycarbonate resin composition having a transmitted light hue similar to that of a polymethylmethacrylate opalescent plate, and an illumination lamp cover comprising the composition ,
It is intended to provide a milky board for signs. Hereinafter, the present invention will be specifically described.

The polycarbonate resin used in the present invention is known as a phosgene method in which various dihydroxydiaryl compounds are reacted with phosgene, a known transesterification method in which a dihydroxydiaryl compound is reacted with a carbonic acid ester such as diphenyl carbonate. A polymer obtained by law, and as a typical one,
A polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] can be mentioned.

Examples of the dihydroxydiaryl compound include bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 2,2-bis (4-hydroxyphenyl), in addition to bisphenol A.
Butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4 -Hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane,
2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3,
Bis (hydroxyaryl) alkanes such as 5-dichlorophenyl) propane, bis (hydroxyaryl) such as 1,1-bis (4-hydroxyphenyl) cyclopentane and 1,1-bis (4-hydroxyphenyl) cyclohexane Cycloalkanes, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-
Dihydroxy diaryl ethers such as 3,3′-dimethyldiphenyl ether, 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxy-3,
Dihydroxydiaryl sulfides such as 3'-dimethyldiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-
Examples include dihydroxydiaryl sulfoxides such as 3,3′-dimethyldiphenyl sulfoxide, 4,4′-dihydroxydiphenyl sulfone, and dihydroxydiaryl sulfones such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone. To be These may be used alone or in admixture of two or more, but in addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4′-dihydroxydiphenyl and the like may be mixed and used.

Further, the above-mentioned dihydroxyaryl compound and a phenol compound having a valence of 3 or more as shown below may be mixed and used. As trihydric or higher phenol, phloroglucin, 4,6-dimethyl-2,4,6-tri-
(4-Hydroxyphenyl) -heptene-2,4,6-
Dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -Ethane and 2,2-bis-
[4,4- (4,4′-dihydroxydiphenyl) -cyclohexyl] -propane and the like can be mentioned.

The viscosity average molecular weight of the polycarbonate resin is usually 10,000 to 100,000, preferably 15,000.
~ 40,000. In producing such a polycarbonate resin, a molecular weight modifier, a catalyst and the like can be used if necessary.

Examples of the light diffusing filler (B) used in the present invention include known ones such as calcium carbonate, barium sulfate and various polymer light diffusing agents (for example, JP-A-3-58840). Two or more kinds can be used. Calcium carbonate is particularly preferable. The particle size of the light diffusing filler used in the present invention is not particularly limited, but it is 0.1 to 0.1 in terms of impact resistance, transparency and light diffusing property of the final composition.
30 μm is preferable.

The titanium oxide used as the component (C) in the present invention may be titanium oxide produced by either the chlorine method or the sulfuric acid method. The titanium oxide is usually used in the form of fine powder of 0.1 to 0.5 μm.

The polyhydric alcohols used in the present invention include trimethylolethane, pentaerythritol, glycols such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, polyethylene glycol and polypropylene glycol, and glycerin. And the like, and one kind or two or more kinds can be used. Trimethylolethane is particularly preferable.

The content of polyhydric alcohols in the titanium oxide composition (C) is as small as 0.0001 to 0.05% by weight. If it is less than 0.0001% by weight, the hue of transmitted light cannot be improved, and if it exceeds 0.05% by weight, the physical properties inherent to the polycarbonate resin such as heat discoloration are adversely affected.
Particularly, 0.0005 to 0.03% by weight is preferable.

There is no limitation on the method for preparing the titanium oxide composition (C) from titanium oxide and polyhydric alcohols, but polyhydric alcohols are usually prepared by mechanical mixing of titanium oxide and polyhydric alcohols. It is possible to obtain a titanium oxide composition by incorporating the above into titanium oxide or by adhering it to the surface of titanium oxide.

In the present invention, the titanium oxide composition (C) containing a polyhydric alcohol is mixed with a polycarbonate resin. In a composition in which a polycarbonate resin, titanium oxide and a polyhydric alcohol are mixed together, the effect of blending the polyhydric alcohol is not exhibited. Therefore, as in the present invention, it is necessary to produce a titanium oxide composition (C) containing a polyhydric alcohol and then mix it with a polycarbonate resin.

The compounding ratio of the polycarbonate resin (A) to the light diffusing filler (B) and the titanium oxide composition (C) is such that the light diffusing filler (B) is 0 per 100 parts by weight of the polycarbonate resin (A). 0.01 to 5 parts by weight and 0.0001 to 5 parts by weight of the titanium oxide composition (C). When the light diffusing filler (B) is less than 0.01 parts by weight, the light diffusing property is poor, and when it exceeds 5 parts by weight, the transparency and mechanical strength are poor, which is not preferable. Further, if the titanium oxide composition (C) is less than 0.0001 parts by weight, the light shielding property is inferior, and if it exceeds 5 parts by weight, the mechanical strength is inferior, which is not preferable. From the viewpoints of light diffusivity, transparency, mechanical strength and the like of the final composition, 100 parts by weight of the polycarbonate resin (A), the light diffusing inorganic filler (B)
0.01 to 3 parts by weight and titanium oxide composition (C) 0.
01 to 3 parts by weight is particularly preferred.

The mixing method of the titanium oxide composition (C) containing the polycarbonate resin (A), the light diffusing inorganic filler (B) and the polyhydric alcohol is not particularly limited, and a known mixer is used. For example, it can be performed by mixing with a tumbler, a ribbon blender, a high speed mixer or the like, and melt kneading.

Upon mixing, if necessary, known additives such as release agents, antistatic agents, antioxidants, ultraviolet absorbers, flame retardants, dyes and pigments (titanium oxide, etc.), and other thermoplastics. Resins such as polymethylmethacrylate, polybutylene terephthalate, polyethylene terephthalate, and styrene resins can be blended.

The present invention will be specifically described below with reference to examples, but the invention is not limited to these examples. Moreover, "part" is based on a weight basis.

Example A commercially available titanium oxide C-i (containing no polyhydric alcohols, particle size 0.4 μm) and the polyhydric alcohols shown in Table 1 were mixed in a mixing ratio of 110 with a mixer. The titanium oxide compositions C-1 to C-5 were manufactured by mixing at 0 ° C.

[0021]

[Table 1]

Examples 1 to 5 and Comparative Examples 1 to 100 Polycarbonate resin (viscosity average molecular weight 22000 consisting of bisphenol A and phosgene) 100 parts, calcium carbonate (particle size 4.5 μm) 2.5 parts and oxidation shown in Table 1. Titanium (composition) C-i, C-1 to 5, and C-ii (commercial titanium oxide, polyhydric alcohol-free, particle size 0.18)
μ), C-iii (commercially available titanium oxide, polyhydric alcohols-free, particle size 0.35 μ) and 1.0 part of each were mixed in a tumbler, then granulated at 270 ° C. in an extruder and pelletized. did. The obtained pellets are treated with an injection molding machine at 30
A two-stage plate having 1 mm and 2 mm thick portions was molded at 0 ° C. Using the 1 mm thick portion of the injection plate, the hue was measured according to JIS Z8705 and a * and b * were recorded. The results are shown in Table 2. In the reference example, a commercially available 1 mm thick polymethylmethacrylate opalescent plate was measured as it was. As is clear from Table 2, when a titanium oxide composition containing a polyhydric alcohol was used, a hue similar to that of a polymethylmethacrylate opalescent plate could be obtained.

[0023]

[Table 2]

[0024]

INDUSTRIAL APPLICABILITY In a polycarbonate resin composition containing a light diffusing filler, by using a titanium oxide composition containing a trace amount of polyhydric alcohols, excellent transparency and mechanical properties which are inherent features of the polycarbonate resin can be obtained. It is possible to provide a polycarbonate resin composition having a transmitted light hue similar to that of a polymethylmethacrylate opalescent plate, without sacrificing the optical strength and the light diffusibility by blending the light diffusing filler.

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-63-265918 (JP, A) JP-A-57-36157 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 69/00

Claims (3)

(57) [Claims] 1. A polycarbonate resin composition comprising 100 parts by weight of a polycarbonate resin (A), 0.01 to 5 parts by weight of a light diffusing filler (B), and 0.0001 to 5 parts by weight of a titanium oxide composition (C). In the product, a titanium oxide composition (C) comprising titanium oxide and a polyhydric alcohol and containing 0.0001 to 0.05% by weight of a polyhydric alcohol is used as the titanium oxide composition (C). A characteristic polycarbonate resin composition. 2. A lighting lamp cover made of the polycarbonate resin composition according to claim 1. 3. A milky board for signs, comprising the polycarbonate resin composition according to claim 1.