Polycarbonate Blends with Modified ABS for Electroplate Adhesion
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Solution Overview
Problem
Thermoplastic blends of polycarbonate and acrylonitrile-butadiene-styrene (ABS) face challenges in achieving improved electroplate adhesion, especially with increased polycarbonate content, which often results in reduced adhesion values and issues like 'bald-spots' and failures such as worm-tracking and thermal-shock.
Innovation Solution
Incorporating a primary and secondary impact modifier into the thermoplastic compositions, with specific weight percentages of polycarbonate resins, acrylonitrile butadiene styrene terpolymers, and emulsion polymerized acrylonitrile butadiene styrene, to enhance electroplate adhesion while allowing for higher polycarbonate content without compromising adhesion values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polycarbonate content is increased in PC/ABS blends, then heat resistance and structural properties are improved, but electroplate adhesion deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the ABS component by incorporating specific rubber particles with controlled butadiene content (20-40 wt%) and using copolymerized units with ester groups. This parameter modification allows the blend to maintain high polycarbonate content (40-80 wt%) while preserving electroplate adhesion through the modified rubber phase that prevents bald-spot formation
Solution Approach 2:
The patent creates a composite material system where polycarbonate is blended with modified ABS containing rubber-reinforced styrene resin. The composite structure combines the heat resistance of polycarbonate with the improved adhesion properties of the modified rubber-containing ABS, achieving both desired properties simultaneously
2Strength
If polycarbonate content is increased in PC/ABS blends, then mechanical strength and rigidity are improved, but electroplate adhesion deteriorates
Solution Approach 1:
The patent modifies the ABS component parameters by incorporating rubber particles with specific butadiene content (20-40 wt%) and adding ester-containing copolymerized units. This parameter change enables the blend to achieve high mechanical strength from polycarbonate while maintaining adhesion through the modified rubber phase that ensures adequate butadiene distribution
Solution Approach 2:
The modified rubber-containing ABS acts as an intermediary phase between the polycarbonate matrix and the electroplate coating. The rubber particles with controlled butadiene content serve as active species that mediate adhesion, preventing the bald-spot defects that would otherwise occur at high polycarbonate concentrations
3Reliability
If neat ABS is used, then electroplate adhesion is excellent, but impact resistance and toughness are reduced
Solution Approach 1:
The patent creates a composite material where modified ABS (containing 20-40 wt% rubber) is blended with polycarbonate. This composite structure combines the excellent adhesion of ABS with the enhanced impact resistance and structural properties of polycarbonate, achieving a balance between adhesion and mechanical performance
Solution Approach 2:
The patent modifies the ABS composition parameters by incorporating rubber particles with controlled butadiene content (20-40 wt%). This parameter modification allows the material to maintain good electroplate adhesion while significantly improving impact resistance compared to neat ABS
Data Source
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AI summary
The present disclosure relates to thermoplastic polycarbonate blends compositions having, among other characteristics, improved electroplate adhesion properties. In particular, the disclosure relates to such polycarbonate compositions comprising a polycarbonate component, a primary ABS impact modifier, and a secondary impact modifier chemically different from the primary impact modifier. Also included herein are methods for preparing and/or using the same, as well as articles formed from such compositions/blends.