Leather-like sheet
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Solution Overview
Problem
Sports shoes used in gymnasiums face challenges with frictional heat melting and bending resistance, requiring a leather-like sheet with high frictional melt resistance and bending resistance.
Innovation Solution
A leather-like sheet comprising a fiber base material, an intermediate resin layer, and a surface resin layer with polyether-based polyurethane and spherical fine particles that have heat resistance at 200°C, specific heat of 0.95 kJ/(kg·K) or more, and controlled particle size distribution, providing a combination of high frictional melt resistance and bending resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional leather-like sheet with resin skin layer is used, then the surface has basic wear resistance, but the surface melts due to frictional heat during repeated rubbing in gymnasium sports
Solution Approach 1:
The patent changes the physical parameters of the surface layer by incorporating spherical fine particles with specific heat capacity (0.95 kJ/(kg·K) or more) and controlled particle size distribution (D50: 2.5-10 μm, D50/D10≤3). These parameter changes enable the surface to dissipate frictional heat more effectively, preventing melting while maintaining surface integrity during repeated rubbing in gymnasium sports.
Solution Approach 2:
The patent creates a composite surface resin layer combining polyether-based polyurethane with spherical fine particles (melamine resin, benzoguanamine resin, or polytetrafluoroethylene resin). This composite structure provides both the elasticity needed for bending resistance and the thermal properties needed for frictional melt resistance, solving the problem of surface melting under repeated friction.
2Object-affected harmful factors
If the surface resin layer is made thicker to improve frictional melt resistance, then heat resistance improves, but bending resistance deteriorates due to cracking under repeated bending
Solution Approach 1:
The patent optimizes the particle size parameters of spherical fine particles (D50: 2.5-10 μm, D50/D10≤3) to achieve a balance between frictional melt resistance and bending resistance. The controlled narrow size distribution ensures uniform dispersion and stress distribution, allowing the surface resin layer to withstand repeated bending (300,000+ cycles) without cracking while maintaining heat resistance.
Solution Approach 2:
The patent creates local quality differentiation within the surface resin layer through the strategic distribution of spherical fine particles. The particles concentrate in regions experiencing high frictional heat, providing localized thermal management, while the polyether-based polyurethane matrix maintains overall flexibility and bending resistance throughout the layer.
3Object-affected harmful factors
If spherical fine particles with high specific heat are added to improve frictional melt resistance, then heat resistance improves, but the surface becomes rough and bending resistance decreases
Solution Approach 1:
The patent precisely controls the particle size parameters (D50: 2.5-10 μm, D50/D10≤3) to maintain surface smoothness while achieving high frictional melt resistance. The narrow size distribution ensures uniform particle packing and surface finish, preventing roughness that would compromise bending resistance, while the high specific heat particles (0.95 kJ/(kg·K) or more) effectively manage frictional heat.
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 leather-like sheet achieves a surface with high frictional melt resistance and bending resistance, with a flexing endurance test showing cracking at 300,000 cycles or more, maintaining mechanical properties and appearance.
Implementation Method 1
the spherical fine particles has a specific heat of 0.95 kJ/(kg·K) or more
Implementation Method 2
the surface resin layer contains a polyether-based polyurethane
Implementation Method 3
a particle size D50 (median diameter) at a cumulative distribution of 50 vol %, of 2.5 to 10 μm, and a particle size D10 at a cumulative distribution of 10 vol % of the spherical fine particles satisfies a condition that a particle size dispersity D50/D10≤3
Data Source
AI summary
A leather-like sheet includes: a fiber base material; an intermediate resin layer stacked on one surface of the fiber base material; and a surface resin layer stacked on the intermediate resin layer. The surface resin layer contains a polyether-based polyurethane and spherical fine particles having a heat resistance at 200° C., and has a content ratio of the spherical fine particles of 5 to 40 mass %. The spherical fine particles have a specific heat of 0.95 kJ/(kg·K) or more, a particle size D50 (median diameter) at a cumulative distribution of 50 vol %, of 2.5 to 10 μm, and a particle size D10 at a cumulative distribution of 10 vol % of the spherical fine particles which satisfies a condition that a particle size dispersity D50/D10≤3.