PBT Polyester Ethylene Copolymer Hydrolytic Stability
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Solution Overview
Problem
Polybutylene terephthalate (PBT) deteriorates in high temperature and humid environments due to hydrolysis, affecting its mechanical and electrical properties, limiting its use in applications like automotive and electronic components.
Innovation Solution
A composition comprising polyester and an ethylene copolymer with an epoxy comonomer, such as glycidyl methacrylate, which enhances hydrolytic stability, allowing the material to retain tensile strength and impact resistance in hostile environments with high humidity and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PBT is used in humid and high temperature environment, then the material provides good mechanical and electrical properties at lower temperatures, but the material undergoes hydrolysis and deteriorates
Solution Approach 1:
The patent combines PBT with ethylene copolymer containing epoxy groups to create a composite material system. The epoxy groups react with carboxyl end groups of PBT to form crosslinked structures, creating a composite that maintains the base PBT's mechanical properties while adding hydrolytic stability through the crosslinked network that resists water attack.
Solution Approach 2:
The ethylene copolymer with epoxy groups acts as an intermediary that reacts with the carboxyl end groups of PBT. This intermediary substance modifies the PBT's chemical structure by forming crosslinks, thereby preventing direct hydrolysis of the PBT ester bonds while maintaining the desired mechanical properties.
2Adaptability or versatility
If PBT is used in automotive under-hood applications, then the material meets standard operating conditions, but it fails under higher temperature and humidity trends
Solution Approach 1:
The patent changes the chemical parameters of PBT by introducing crosslinked structures through epoxy-carboxyl reactions. This parameter change (from linear to crosslinked structure) fundamentally alters the material's response to environmental conditions, enabling it to withstand higher temperatures and humidity that would otherwise cause hydrolysis and failure.
Solution Approach 2:
By creating a composite system of PBT and ethylene copolymer with epoxy groups, the material achieves enhanced environmental adaptability. The crosslinked network formed by the epoxy groups creates a more robust structure that can tolerate the extreme parameter variations found in modern automotive under-hood environments.
3Ease of manufacture
If pure PBT is used to produce articles, then the production process is simple and cost-effective, but the articles lack sufficient hydrolytic stability
Solution Approach 1:
The patent employs a composite material approach where PBT is combined with ethylene copolymer containing epoxy groups. This composite formulation maintains manufacturing simplicity as both components are processable by standard PBT processing techniques, while simultaneously providing the hydrolytic stability needed for long-term durability in humid environments.
Solution Approach 2:
The invention modifies the compositional parameters of PBT by adding a small amount of ethylene copolymer with epoxy groups. This parameter change (composition modification) enables hydrolytic stability without significantly complicating the manufacturing process, as the modified material can be processed using conventional PBT extrusion and molding equipment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The addition of ethylene copolymer with epoxy comonomers significantly improves the retention of tensile strength and impact resistance of PBT-based articles, maintaining at least 50% of their properties after exposure to high humidity and temperature, making them suitable for use in harsh conditions.
Implementation Method 1
At high temperature, water or water vapor hydrolyzes the ester bond and forms hydroxyl group and carboxyl group.
Implementation Method 2
A composition comprising polyester and an ethylene copolymer with an epoxy comonomer, such as glycidyl methacrylate, which enhances hydrolytic stability
Data Source
AI summary
An article and process for using the article under a high temperature and high humidity condition are disclosed. The article comprises or is produced from polyester, at least one ethylene copolymer, and optionally an additive and includes one or more automobile parts and electronic or electrical connectors. The process comprises employing the composition or an article in a hostile environment including a temperature of 60° C. or higher and a relative humidity of at least 60%.