Resin Composition for Transparent Automobile Meter Panel Covers
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Solution Overview
Problem
Methacrylic resins used in automobile transparency members lack sufficient heat resistance, despite their excellent transparency and mechanical properties, and existing solutions do not adequately address this issue while maintaining other desired characteristics like surface hardness and impact resistance.
Innovation Solution
A resin composition comprising 55-70% styrene-based copolymer and 30-45% methacrylic resin, where the styrene-based copolymer includes 45-85% aromatic vinyl monomer, 5-45% (meth)acrylic ester monomer, and 10-30% unsaturated dicarboxylic anhydride monomer units, with a weight average molecular weight of 100,000 to 300,000, providing enhanced heat resistance, transparency, and impact strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If methacrylic resin is used for transparent automobile members, then transparency and mechanical properties are improved, but heat resistance deteriorates
Solution Approach 1:
The patent uses a composite resin system combining methacrylic resin with styrene-based copolymer and unsaturated dicarboxylic anhydride to achieve both transparency and heat resistance. The specific composition (5-50 mass% styrene-based copolymer, 50-95 mass% methacrylic resin, and 0.1-5 mass% unsaturated dicarboxylic anhydride) creates a material that maintains the optical clarity of methacrylic resin while gaining the heat resistance of the styrene-based components.
2Temperature
If styrene-based copolymer is blended with methacrylic resin to improve heat resistance, then heat resistance is improved, but surface hardness may deteriorate
Solution Approach 1:
The patent optimizes the composition parameters within specific ranges: 5-50 mass% styrene-based copolymer, 50-95 mass% methacrylic resin, and 0.1-5 mass% unsaturated dicarboxylic anhydride. By precisely controlling these parameter ranges, the invention achieves the optimal balance between heat resistance improvement and surface hardness maintenance, preventing the surface hardness deterioration that can occur with excessive styrene-based copolymer content.
3Temperature
If high proportion of styrene-based copolymer is used to improve heat resistance, then heat resistance is improved, but transparency deteriorates
Solution Approach 1:
The patent establishes the optimal parameter range for styrene-based copolymer content as 5-50 mass%, with the upper limit set at 50 mass% to prevent transparency deterioration. This parameter control ensures that sufficient heat resistance is achieved through the styrene-based components while maintaining the high transparency characteristic of methacrylic resin-based materials.
Data Source
AI summary
A resin composition capable of producing a molded article excellent in transparency, heat resistance, surface hardness, impact resistance and hue is provided. According to the present invention, there is provided a resin composition comprising 15 to 100 mass% of a styrene-based copolymer (A) and 0 to 85 mass% of a methacrylic resin(B), wherein the styrene-based copolymer (A) comprises 45 to 85 mass% of an aromatic vinyl monomer unit, 5 to 45 mass% of a (meth)acrylic ester monomer unit, and 10 to 30 mass% of an unsaturated dicarboxylic anhydride monomer unit, and has a weight average molecular weight(Mw) of 100,000 to 300,000, and a total light transmittance of 89 % or more for a thickness of 2 mm.