Lightweight Polymer Outsole via Composite Material Design
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Solution Overview
Problem
Conventional outsoles are heavy due to their high density, making it difficult to achieve a lightweight shoe, as there is no suitable low-density polymer crosslinked product available for forming the outsole.
Innovation Solution
A polymer crosslinked product is developed by blending a thermoplastic resin with rubber, which has a specific relationship between storage moduli at different temperatures and a density of 1.0 g/cm3 or less, providing a lightweight and strong outsole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a conventional outsole made of crosslinked rubber product is used, then the outsole has sufficient strength and durability, but the outsole weight is high
Solution Approach 1:
The patent uses a composite material system consisting of rubber and thermoplastic resin in specific proportions (rubber 95-99 parts, thermoplastic resin 1-5 parts by mass). This composite structure allows the outsole to achieve both lightweight properties and sufficient strength, resolving the contradiction between weight reduction and strength maintenance.
Solution Approach 2:
The patent changes the compositional parameters by controlling the ratio of rubber to thermoplastic resin within specific ranges, and by controlling the storage modulus ratio (E23/E160) to be within 0.05-5.0. These parameter changes enable the outsole to achieve optimal balance between weight and strength.
2Weight of moving object
If the density of the polymer crosslinked product is reduced to achieve lightweight, then the outsole weight decreases, but the mechanical properties may deteriorate
Solution Approach 1:
The composite of rubber and thermoplastic resin provides both lightweight properties and stable mechanical properties. The thermoplastic resin component (1-5 parts by mass per 100 parts rubber) reinforces the rubber matrix, ensuring that reducing density does not compromise mechanical reliability.
Solution Approach 2:
By controlling the storage modulus ratio (E23/E160) within 0.05-5.0, the patent ensures that the material maintains appropriate mechanical properties across temperature variations while achieving lightweight density (1.0 g/cm³ or less).
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 solution results in an outsole with improved lightweight properties and mechanical strength, reducing the overall shoe weight while maintaining necessary durability and flexibility.
Implementation Method 1
a reinforcing effect is exerted on a rubber by blending a thermoplastic resin in the rubber
Implementation Method 2
a polymer crosslinked product including a rubber and a thermoplastic resin is formed to have a certain relationship between a storage modulus at an ordinary temperature and a storage modulus at a high temperature
Data Source
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AI summary
Provided in the present invention is an outsole formed of a polymer crosslinked product having a JIS A hardness of 90 or less and a tear strength of 40 kgf/cm or more and having a certain relationship between a storage modulus (E23) at 23 °C and 10 Hz and a storage modulus (E160) at 160 °C and 10 Hz, to reduce the weight of a shoe.