EPDM Rubber Resin Composition for Heat-Resistant Cross-Linked Foam
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Solution Overview
Problem
Conventional cross-linked foams used in shoe soles lack desired physical properties such as strength and rebound resilience, especially in terms of heat resistance, despite modifications in polymer composition or blending ratios.
Innovation Solution
A resin composition comprising a thermoplastic resin, ethylene propylene diene monomer rubber with an ethylene content lower than 70 mass %, and a cross-linking agent, along with a foaming agent, is used to produce a cross-linked foam that balances strength and resilience, with specific ratios and additives to enhance heat resistance and foaming properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cross-linked foam is used with standard polymer composition, then heat resistance is achieved, but rebound resilience and strength are insufficient
Solution Approach 1:
The patent changes the chemical composition parameters by introducing EPDM rubber with specific ethylene content (lower than 70 mass %) and controlling its proportion (5 mass % or more of the sum of thermoplastic resin and EPDM). This parameter change resolves the contradiction by achieving both heat resistance and improved rebound resilience through the specific rubber composition and cross-linking structure.
Solution Approach 2:
The patent creates a composite material system combining thermoplastic resin, EPDM rubber, cross-linking agent, and foaming agent. This composite approach allows the foam to simultaneously achieve heat resistance from the cross-linked structure and improved rebound resilience from the rubber phase, resolving the contradiction between durability and physical performance.
2Temperature
If polymer composition is modified to improve heat resistance, then thermal stability increases, but strength and rebound resilience deteriorate
Solution Approach 1:
The patent modifies the composition parameters by specifying EPDM rubber with ethylene content lower than 70 mass % and controlling the ratio of EPDM to thermoplastic resin (5 mass % or more). This precise parameter control allows the foam to achieve both thermal stability and maintained rebound resilience, overcoming the trade-off between heat resistance and mechanical properties.
3Reliability
If cross-linking density is increased to improve heat resistance, then thermal stability improves, but strength and elasticity decrease
Solution Approach 1:
The patent controls the cross-linking parameters by selecting specific cross-linking agents and controlling their proportions, while simultaneously controlling the EPDM rubber content (5 mass % or more of the sum of thermoplastic resin and EPDM). This balanced parameter control achieves adequate heat resistance while preserving the strength and elasticity needed for shoe sole applications.
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 resulting cross-linked foam exhibits improved resilience and strength equivalent to conventional foams while maintaining low specific gravity, suitable for use in shoe soles, particularly in sports shoes that require heat resistance.
Implementation Method 1
a cross-linked foam made from a polymer such as a styrene-based thermoplastic elastomer has been suggested
Implementation Method 2
a resin composition to be cross-linked and foamed including a thermoplastic resin, a cross-linking agent, and a foaming agent
Data Source
AI summary
A resin composition to be cross-linked and foamed includes thermoplastic resin, a cross-linking agent, and a foaming agent, further including: ethylene propylene diene monomer rubber having an ethylene content lower than 70 mass %. The ethylene propylene diene monomer rubber amounts for 5 mass % or more of a sum of the thermoplastic resin and the ethylene propylene diene monomer rubber.