Polycarbonate Resin Composition Chemical Resistance
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Solution Overview
Problem
Polycarbonate resin used in portable electronic devices faces challenges with mechanical properties and impact strength due to penetration of paint diluents, leading to insufficient transparency and impact resistance when painted, and existing solutions like blending with ester-based or sulfone-based polymers do not fully address these issues.
Innovation Solution
A polycarbonate resin composition comprising aromatic polycarbonate, siloxane-based polycarbonate, and syndiotactic polystyrene, with specific weight percentages and molecular weight ranges, that enhances fluidity, injection moldability, impact strength, chemical resistance, and transparency, while allowing for the inclusion of additives like UV stabilizers and pigments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polycarbonate resin is used as exterior material for portable electronic devices, then transparency and impact strength are improved, but chemical resistance deteriorates due to penetration of paint diluents
Solution Approach 1:
The patent uses a composite material system consisting of polycarbonate resin blended with acrylic resin to create a material that combines the impact strength of polycarbonate with the chemical resistance of acrylic, resolving the contradiction between these two properties
Solution Approach 2:
The patent changes the chemical composition parameters by controlling the blending ratio of polycarbonate and acrylic resins, and adjusts molecular weight parameters to optimize both impact strength and chemical resistance simultaneously
2Reliability
If polycarbonate resin is blended with ester-based polymers or sulfone-based polymers to improve chemical resistance, then chemical resistance is improved, but transparency and impact strength deteriorate
Solution Approach 1:
The patent changes the resin type parameter from ester-based or sulfone-based polymers to acrylic resin, which has different chemical properties that maintain transparency and impact strength while providing chemical resistance
Solution Approach 2:
The patent applies acrylic resin specifically to provide chemical resistance at the surface level where paint diluent contact occurs, while maintaining the bulk polycarbonate structure that provides impact strength and transparency
3Strength
If rubber-based impact reinforcing agent is added to polycarbonate resin to improve impact strength, then impact strength is improved, but transparency deteriorates
Solution Approach 1:
The patent changes the impact reinforcement mechanism from rubber-based particulate reinforcement to acrylic resin blending, which maintains the amorphous transparent structure while providing impact resistance through molecular-level compatibility
Data Source
AI summary
A polycarbonate resin composition includes: (A) an aromatic polycarbonate in an amount of about 5 to about 95% by weight, (B) a siloxane-based polycarbonate in an amount of about 5 to about 90% by weight, and (C) a syndiotactic polystyrene in an amount of 0 to about 5% by weight. The polycarbonate resin composition can have excellent flowability, injection moldability, impact strength, chemical resistance, and transparency.In a preferred embodiment the siloxane-based polycarbonate comprises a compound represented by the following formula in the main chain thereof: