Polycarbonate Resin Composition with Acrylic Copolymer for Scratch Resistance
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Solution Overview
Problem
Polycarbonate resin compositions face challenges in achieving high transparency, scratch resistance, and moldability due to poor compatibility and high melting viscosity, limiting their use in complex-shaped and thin-film electronic appliance housings.
Innovation Solution
A polycarbonate resin composition comprising 40-99% polycarbonate resin and 1-60% acrylic copolymer with a high refractive index and flexible structure, optionally including additional acrylic resin, to enhance compatibility, fluidity, and scratch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If acrylic resin is mixed with polycarbonate resin to improve scratch resistance, then scratch resistance is improved, but transparency and coloring properties deteriorate due to low compatibility and refractive index difference
Solution Approach 1:
The patent changes the chemical composition parameters of the acrylic resin by introducing specific copolymers with controlled refractive indices (1.49-1.56) and compatibility factors. This parameter optimization reduces the refractive index difference between polycarbonate and acrylic components, thereby maintaining transparency while achieving scratch resistance.
Solution Approach 2:
The patent creates a composite resin composition combining polycarbonate with specifically selected acrylic copolymers (such as polymethyl methacrylate, polyethyl methacrylate, or their copolymers with controlled composition). This composite approach leverages the scratch resistance of acrylic while maintaining polycarbonate's transparency through optimized compatibility.
2Strength
If polycarbonate/acrylic resin blends are used to improve scratch resistance, then scratch resistance is improved, but moldability deteriorates due to high melting viscosity
Solution Approach 1:
The patent optimizes the molecular weight and composition parameters of the acrylic copolymer to control the blend's melting viscosity. By selecting copolymers with specific weight average molecular weights and compositions (5-95% methacrylate monomer), the patent achieves a balance where scratch resistance is improved but melt flow characteristics remain suitable for injection molding.
3Strength
If conventional acrylic resin is used to improve scratch resistance, then scratch resistance is improved, but compatibility with polycarbonate deteriorates leading to phase separation
Solution Approach 1:
The patent systematically adjusts the chemical composition parameters of the acrylic resin, specifically using copolymers with 5-95% methacrylate monomer content and controlled refractive indices (1.49-1.56). This parameter optimization enhances interfacial compatibility between polycarbonate and acrylic phases, reducing phase separation while maintaining scratch resistance.
Data Source
AI summary
A polycarbonate resin composition of the present invention comprises about 40 to about 99% by weight of a polycarbonate resin (A), about 1 to about 60% by weight of an acrylic copolymer (B) having a high refractive index and a flexible structure, and about 0 to about 60% by weight of acrylic resin (C). A polycarbonate resin composition of the present invention can have excellent transparency and scratch resistance without requiring extra compatibilizers by including an acrylic copolymer having a high refractive index and a flexible structure with the polycarbonate resin.