Connector Waterproof Body Using Thermoplastic Elastomer
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Solution Overview
Problem
Conventional connectors for wiring harnesses in vehicles lack sufficient adhesiveness to electrical wire coverings, thermal resistance, and flexibility, leading to inadequate waterproofing due to thermal decomposition of syndiotactic polystyrene-based polymers during heat forming operations.
Innovation Solution
A connector design incorporating a thermoplastic elastomer composition comprising a blend of acid-modified and unmodified styrene-based elastomers with syndiotactic polystyrene-based polymers, along with a polyphenylene ether component, which enhances adhesion, thermal resistance, and flexibility while maintaining waterproof properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If syndiotactic polystyrene-based polymer is used for heat resistance, then thermal resistance is improved, but mechanical properties decrease due to thermal decomposition during heat forming operation
Solution Approach 1:
The patent uses a composite material system consisting of syndiotactic polystyrene-based polymer combined with thermoplastic elastomer and specific antioxidants. This composite approach allows the syndiotactic polystyrene to provide thermal resistance while the elastomer and antioxidants compensate for mechanical property losses caused by thermal decomposition during processing.
Solution Approach 2:
The patent converts the harmful effect of thermal decomposition into a benefit by adding specific antioxidants (phenolic antioxidant and triphosphate/diphosphate) that control the decomposition process. The antioxidants transform the harmful thermal decomposition into a controlled process that maintains mechanical properties while still allowing the syndiotactic polystyrene to provide its thermal resistance benefits.
2Ease of manufacture
If thermoplastic elastomer material is used for waterproof body, then flowability is improved, but adhesiveness to covering portion and thermal resistance are insufficient
Solution Approach 1:
The patent creates a composite material system where thermoplastic elastomer provides flowability for easy manufacturing, while syndiotactic polystyrene-based polymer contributes thermal resistance and specific additives enhance adhesiveness to the covering portion. This composite approach allows all three requirements to be met simultaneously.
Solution Approach 2:
The patent applies different material properties to different aspects of the waterproof body: thermoplastic elastomer provides flowability for molding, syndiotactic polystyrene provides thermal resistance, and acid-modified components provide adhesiveness to the covering portion. Each component is optimized for its specific function within the composite system.
3Reliability
If curing resin potting approach is used for waterproof treatment, then waterproof properties are improved, but manufacturing time increases and shape retention is insufficient before curing
Solution Approach 1:
The patent uses thermoplastic elastomer and syndiotactic polystyrene-based polymer that can be processed through melting and cooling phase transitions, eliminating the need for chemical curing. This allows the waterproof body to be formed rapidly through injection molding or similar processes, significantly reducing manufacturing time compared to curing resin approaches.
Solution Approach 2:
The patent changes the material state from requiring chemical curing (time-consuming) to using thermal processing (rapid). By selecting thermoplastic materials and optimizing processing temperature and cooling parameters, the patent achieves rapid formation of the waterproof body with good shape retention, eliminating the time delay associated with curing processes.
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 proposed connector achieves improved adhesiveness, thermal resistance, flexibility, and waterproofing by optimizing the mass ratios of styrene-based elastomers and syndiotactic polystyrene-based polymers, ensuring effective sealing against water penetration and maintaining mechanical integrity under elevated temperatures.
Implementation Method 1
the polymer, due to thermal decomposition occurring during the heat forming operation at the elevated temperature, has a tendency to decrease its molecular weight, thereby decreasing mechanical properties
Data Source
AI summary
The present invention provides a connector, which may comprise a terminal fitting, a connector housing having a terminal receiving chamber in which the terminal fitting is at least partly disposed, and a waterproof body formed of thermoplastic elastomer composition. The thermoplastic elastomer composition may comprise (A) styrene-based elastomer component and (B) syndiotactic polystyrene-based polymer component. (A) Styrene-based elastomer component may comprise (A1) acid-modified styrene-based elastomer and (A2) unmodified styrene-based elastomer. The mass ratio of (A1) acid-modified styrene-based elastomer to the sum of (A1) acid-modified styrene-based elastomer, and (A2) unmodified styrene-based elastomer (A1/(A1+A2)) may be from 0.9 to 0.1. The mass ratio of the (A) styrene-based elastomer component to (B) syndiotactic polystyrene-based polymer component may be from 60:40 to 90:10.