PCT Polyester Composition Heat Aging Resistance
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Solution Overview
Problem
Existing poly(cyclohexylene-dimethylene) terephthalate compositions fail to maintain mechanical properties over long-term high temperature exposure, leading to unacceptable deterioration due to thermo-oxidation, which limits their suitability for high-temperature applications.
Innovation Solution
A polyester composition comprising poly(cyclohexylene-dimethylene) terephthalate polymer, copolyester elastomers, and specific ethylene copolymers such as thermoplastic ethylene alkyl-(meth)acrylate, ethylene acid, and ethylene epoxide copolymers, which are mixed and processed to enhance mechanical properties at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heat stabilizers and impact modifiers are added to polyester compositions, then heat aging resistance is improved, but mechanical properties deteriorate due to thermo-oxidation during long-term high temperature exposure
Solution Approach 1:
The patent employs a composite material system consisting of poly(cyclohexylene-dimethylene) terephthalate polymer combined with specific ethylene copolymers (thermoplastic ethylene alkyl-(meth)acrylate, ethylene acid, and ethylene epoxide copolymers). This composite formulation creates synergistic effects where the ethylene copolymers provide impact modification and heat stabilization while the PCT matrix maintains structural integrity, thereby improving both heat aging resistance and retaining mechanical properties during long-term high temperature exposure
Solution Approach 2:
The patent utilizes parameter changes by selecting specific types of ethylene copolymers with controlled composition and properties. The copolymers contain specific functional groups (alkyl-(meth)acrylate, acid, and epoxide) in controlled amounts, and the patent optimizes their concentration and molecular characteristics to achieve the desired balance between heat resistance and mechanical property retention under thermal aging conditions
2Temperature
If high-heat rubber composites and braided PTFE are used in high temperature environments, then temperature resistance is improved, but structural complexity and cost increase
Solution Approach 1:
The patent achieves temperature resistance through parameter changes in the polymer composition itself rather than adding complex structural elements. By incorporating specific ethylene copolymers with controlled functional groups and optimizing their concentration, the patent elevates the thermal performance of the polyester composition to withstand high temperature environments, thereby avoiding the need for complex multi-layer structures or braided reinforcements
3Adaptability or versatility
If plastic parts are exposed to high temperatures for prolonged periods, then application suitability is improved, but mechanical properties decrease due to thermo-oxidation
Solution Approach 1:
The patent converts the harmful effect of thermal exposure into a beneficial outcome by incorporating ethylene copolymers with specific functional groups that act as thermal stabilizers. These copolymers, particularly those containing acid and epoxide groups, neutralize the detrimental thermo-oxidative effects through chemical interactions, thereby enabling the plastic parts to maintain mechanical properties even after prolonged exposure to high temperatures in automotive and electrical/electronics applications
Data Source
AI summary
The invention relates to polyester compositions comprising a) a poly(cyclohexylene-dtmethylene) terephthalate (PCT) resin, b) at least one copolyester elastomer and c) at least three ethylene copolymers chosen among c1) one or more ethylene alkyl-(meth)acrylvate copolymers; c2) one or more ethylene acid copolymers and/or ionomers thereof; and c3) one or more ethylene epoxide copolymers. The disclosed polyester compositions are particularly well suited for manufacturing articles that maintain good mechanical properties against long-term high temperature exposure, i.e. for high temperature applications.