Thermoplastic resin composition for light reflector, formed article for light reflector, light reflector, and method for producing formed article for light reflector
View Patent ↗Thermoplastic resin compositions for a light reflector contain 2 to 45 parts by mass per 100 parts by mass of a thermoplastic resin (A) of an inorganic filler (B1) treated with a fatty acid type surface treating agent and having an average particle diameter of not more than 3 μm, or 2 to 45 parts by mass of an inorganic filler (B2) having a refractive index α of 1.61≦α≦2.5 and having an average particle diameter of not more than 3 μm, 0.01 to 3 parts by mass of glycerol triester of a fatty acid and/or a glycerol diester of a fatty acid (C1), and 0.01 to 3 parts by mass of a glycerol monoester of a fatty acid (C2). A molded article for a light reflector and a light reflector in which a light reflecting metal layer is directly formed on at least a part of the surface of the molded article is produced from one of such thermoplastic resin compositions.
1. A thermoplastic resin composition for a light reflector comprising:
a thermoplastic resin (A); and
barium sulfate;
wherein
a content of the barium sulfate is 2 to 45 parts by mass per 100 parts by mass of the thermoplastic resin (A),
a refractive index α of the barium sulfate is from 1.61 to 2.5 and
an average particle diameter of the barium sulfate is from 0.05 to 1 μm;
the thermoplastic resin (A) comprises:
polybutylene terephthalate;
polyethylene terephthalate; and
from 4 to 10 mass % of at least one vinyl copolymer thermoplastic resin selected from the group of vinyl thermoplastic resins consisting of an acrylonitrile-styrene copolymer resin having a mass ratio of acrylonitrile to styrene of from 20/80 to 45/55, an epoxy group containing acrylonitrile-styrene copolymer resin having a % by mass composition of 0.1 to 0.4% glycidyl methacrylate, 15 to 40% acrylonitrile and 60 to 84.9% styrene and a maleimide copolymer resin of N-phenyl maleimide/styrene/acrylonitrile having 15 to 60 mass % N-phenyl maleimide;
wherein
a mass ratio of polybutylene terephthalate to polyethylene terephthalate is from 95/5 to 55/45.
2. A molded article for a light reflector comprising the thermoplastic resin composition defined in claim 1 .
3. The molded article for a light reflector according to claim 2 wherein
a light reflectance, at the surface of the molded article is 65% or more at a wave length of light in the range of from 420 to 700 nm and
a linear shrinkage of the molded article is not more than 1.6%.
4. The molded article for a light reflector according to claim 3 wherein the light reflectance, at the surface of the molded article, is 70% or more at a wave length of light in the range of from 420 to 700 nm.
5. A light reflector, comprising:
the molded article defined in claim 3 ; and
a light reflecting metal layer;
wherein the light reflecting metal layer is directly on at least a part of the surface of the molded article.
6. The thermoplastic resin composition for a light reflector according to claim 1 wherein the barium sulfate is a settleable barium sulfate.
7. The thermoplastic resin composition for a light reflector according to claim 6 wherein the particle diameter of the settleable barium sulfate is from 0.1 to 0.3 μm.