Thermoset Polyurethane Shoe Upper with Textile Reinforcement
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Solution Overview
Problem
Existing shoe upper materials, particularly those using thermoplastic polyurethane (TPU), face issues such as yellowing when exposed to light, susceptibility to hydrolysis leading to delamination, and the need for additional adhesive layers which increase weight and impair material quality, while omitting adhesives can result in inadequate bonding.
Innovation Solution
A composite material for shoe uppers comprising an inner and outer thermoset polyurethane layer with a textile reinforcing layer in between, where the polyurethane layers bond through apertures in the textile layer under heat and pressure, eliminating the need for additional adhesives and enhancing mechanical and chemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TPU is used as the material for shoe upper, then the material provides good flexibility and bonding, but it discolors when exposed to light and is susceptible to hydrolysis leading to delamination
Solution Approach 1:
The patent changes the chemical composition parameters by using thermoset polyurethane instead of thermoplastic polyurethane (TPU). This material substitution fundamentally alters the chemical stability parameters, providing resistance to yellowing and hydrolysis while maintaining the required mechanical properties for shoe upper material.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers including textile material and polyurethane layers. This composite approach combines the advantages of different materials to achieve both flexibility and improved chemical stability, resolving the contradiction between material performance and long-term durability.
2Strength
If an adhesive layer is added to bond TPU with other materials, then the bonding is improved, but the weight increases and material quality is impaired
Solution Approach 1:
The patent merges the bonding function directly into the polyurethane layer itself through hot-melt bonding, eliminating the need for a separate adhesive layer. The polyurethane material is applied in a molten state and bonds directly to the textile substrate, achieving strong adhesion without adding extra weight or compromising material quality.
Solution Approach 2:
The patent extracts and removes the adhesive layer from the material structure entirely. By using hot-melt bonding where the polyurethane itself serves as the bonding agent, the separate adhesive component is eliminated, reducing weight and avoiding the quality issues associated with additional adhesive layers.
3Weight of moving object
If the polyurethane layer is made thinner to reduce weight, then the weight is reduced, but the abrasion resistance and stability decrease
Solution Approach 1:
The patent changes the physical and chemical parameters of the polyurethane material, specifically using thermoset polyurethane with enhanced mechanical properties. This allows for thinner layer thickness while maintaining or improving abrasion resistance and structural stability compared to conventional thermoplastic materials.
Solution Approach 2:
The patent uses a composite structure with textile material and polyurethane layers working together. The textile substrate provides structural support and abrasion resistance, allowing the polyurethane layer to be thinner while maintaining overall material strength and durability.
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 a lightweight shoe upper with improved durability, abrasion resistance, and UV stability, maintaining elasticity without the drawbacks of TPU, while ensuring a strong bond between layers without additional weight or quality impairment.
Implementation Method 1
The material may be pressed under heat so that the inner polyurethane layer and the outer polyurethane layer bond to each other through a plurality of the apertures of the textile reinforcing layer
Data Source
AI summary
Described are materials for a shoe upper, in particular for soccer shoes, with a particularly low weight. The material includes an inner polyurethane layer, an outer polyurethane layer, and a textile reinforcing layer. The textile reinforcing layer is arranged between the inner polyurethane layer and the outer polyurethane layer. The inner polyurethane layer and the outer polyurethane layer comprise thermoset polyurethane. The textile reinforcing layer comprises apertures through which the inner polyurethane layer and the outer polyurethane layer are connected to each other.