Polyolefin Compound Co-Continuous Phase Footwear Shock Absorption
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Solution Overview
Problem
Current footwear shock absorption materials, such as traditional foamed midsoles, face challenges in providing optimal mechanical strength, adhesion, and aesthetic appeal while maintaining lightweight and comfortable designs, often requiring expensive high-performance polymers like TPU and PEE.
Innovation Solution
Development of a polyolefin compound comprising a thermoplastic olefin copolymer and a functional polymer, such as ethylene vinyl acetate, which forms a co-continuous phase for enhanced adhesion and shock absorption, allowing for the creation of cost-effective, injection-molded shock-absorbing layers with improved thermal resistance and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional foamed midsoles are used for shock absorption, then comfort and shock absorption are improved, but mechanical strength and adhesion deteriorate
Solution Approach 1:
The patent uses a composite material system consisting of polyolefin elastomer (POE) combined with polypropylene (PP) and ethylene vinyl acetate (EVA). This composite formulation allows the material to simultaneously achieve shock absorption properties from the elastomeric POE component and enhanced mechanical strength from the PP and EVA components, resolving the contradiction between comfort and structural integrity.
Solution Approach 2:
The patent optimizes the molecular weight distribution and composition ratios of the polyolefin elastomer and its components. By controlling the molecular weight range (Mw/Mn ratio) and the proportions of POE, PP, and EVA, the material achieves optimal balance between shock absorption and mechanical strength, allowing the same material to provide both cushioning and structural support.
2Strength
If high-performance polymers like TPU and PEE are used, then mechanical strength and adhesion are improved, but material cost increases
Solution Approach 1:
The patent employs polyolefin elastomer (POE), polypropylene (PP), and ethylene vinyl acetate (EVA) as cost-effective alternative materials to expensive high-performance polymers like TPU and PEE. These materials provide sufficient mechanical strength and adhesion for footwear applications at lower cost, making the shoe more affordable while maintaining acceptable performance levels.
Solution Approach 2:
By formulating a composite of POE, PP, and EVA, the patent achieves cost reduction without significant sacrifice in performance. The synergistic combination allows each component to contribute its strengths: POE provides elasticity and shock absorption, PP provides structural stability, and EVA provides adhesion, collectively replacing the need for expensive single-material systems like TPU or PEE.
3Reliability
If thicker midsole layers are added for shock absorption, then shock absorption is improved, but weight increases
Solution Approach 1:
The patent optimizes the material density and composition to achieve maximum shock absorption with minimum material usage. By carefully selecting the molecular weight distribution and composition ratios of the POE/PP/EVA system, the material provides high shock absorption performance per unit weight, allowing thinner midsole construction that reduces overall shoe weight while maintaining protective function.
Data Source
Figure 1A~2B
Figure 3A~3B
AI summary
A polyolefin compound including: A) at least one thermoplastic olefin copolymer including the reaction product of olefin 1 and olefin 2, wherein: olefin 1 is a C2 based olefin and olefin 2 is a C3 to C8 a-olefin or olefin 1 is a C3 based olefin and olefin 2 is a C4 to C8 a-olefin; B) at least one functional polymer, the functional polymer content in the polyolefin compound being between 1 and 75 weight percent of the combined components A and B; wherein the thermoplastic olefin copolymer and the functional polymer form a co- continuous phase; wherein: a) an 12 melt index of the polyolefin compound is from about 1 to about 15 as measured using ASTM D 1238; b) a Shore A hardness of the polyolefin compound is from about 55 to about 100 as measured using ASTM D2240; c) a flexural modulus of the polyolefin compound is from about 0.8 to about 30 kpsi as measured using ASTM D790.