Silane-Crosslinked OBC Foam Beads for Shrinkage-Free Sintering
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Solution Overview
Problem
Existing crosslinked ethylene-based polymers used in footwear components face challenges in foaming technology due to high density, instability at high temperatures, and shrinkage during sintering, limiting their suitability for bead foaming and automation in footwear production.
Innovation Solution
A process involving crosslinking silane-grafted ethylene/α-olefin multi-block copolymer pellets to a gel content of 10% to 80% to form crosslinked Si-g-OBC foam beads with a density of less than 0.200 g/cc, suitable for bead foaming technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If crosslinked ethylene-based polymers are used for bead foaming, then foaming capability is improved, but density increases and high-temperature stability deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the gel content within 10-80% to achieve the optimal balance between foaming capability and high-temperature stability. This parameter optimization allows the polymer to foam properly while maintaining dimensional stability during sintering
Solution Approach 2:
The patent uses composite materials by combining silane-grafted ethylene/α-olefin multi-block copolymer with specific gel content ranges, creating a material that exhibits both good foaming properties and high-temperature stability, resolving the contradiction between ease of manufacture and temperature resistance
2Ease of manufacture
If crosslinked ethylene-based polymers are used for bead foaming, then foaming capability is improved, but shrinkage increases at high temperature
Solution Approach 1:
The patent controls gel content within 10-80% to optimize the balance between foaming capability and shrinkage resistance, ensuring the foam beads maintain their shape during high-temperature sintering while remaining easy to manufacture
Solution Approach 2:
The patent performs preliminary crosslinking of the silane-grafted polymer before foaming, which creates a network structure that prevents shrinkage during subsequent sintering while maintaining good foaming capability
3Ease of manufacture
If chemical blowing agents are used for foaming, then foaming process is simple, but environmental pollution and odor increase
Solution Approach 1:
The patent replaces chemical blowing agents with physical foaming methods, substituting a chemical-based system with a physical-based system that uses pressure and temperature control to achieve foaming without harmful chemical byproducts
Solution Approach 2:
The patent converts the potential harm of complex processing into a benefit by using physical foaming that requires no additional chemical agents, thereby eliminating odor and contamination issues while maintaining manufacturing efficiency
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 process produces stable foam beads that maintain shape at high temperatures, enabling efficient foaming and sintering without shrinkage, facilitating automation and reducing environmental impact and costs in footwear production.
Implementation Method 1
crosslinking pellets composed of a silane-grafted ethylene/α-olefin multi-block copolymer (Si-g-OBC) to a gel content from 10% to 80%
Implementation Method 2
foaming the crosslinked Si-g-OBC pellets to form crosslinked Si-g-OBC foam beads
Implementation Method 3
sintering the crosslinked Si-g-OBC foam beads to form a sintered foam structure
Data Source
AI summary
The present disclosure provides a process. The process includes (i) crosslinking pellets composed of a silane-grafted ethylene/α-olefin multi-block copolymer (Si-g-OBC) to a gel content from 10% to 80% to form crosslinked Si-g-OBC pellets; and (ii) foaming the crosslinked Si-g-OBC pellets to form crosslinked Si-g-OBC foam beads having a gel content from 10% to 80%.