Puncture resistant material
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Solution Overview
Problem
Existing shoe sole materials lack the combination of puncture resistance, flexibility, and low weight/thickness, as steel plates are inflexible and uncomfortable, while fabric-based solutions fail to meet desired performance standards.
Innovation Solution
A puncture-resistant material is created by weaving high-strength continuous filament polypropylene fibers and needle-punching thermoplastic fibers perpendicularly, followed by heat treatment and calendaring to increase density and form a monolithic, flexible shoe sole material that meets ASTM standards for puncture resistance and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel plate is used for shoe sole protection, then puncture resistance is improved, but flexibility and comfort deteriorate
Solution Approach 1:
The patent uses composite materials consisting of woven polypropylene fabric layers combined with thermoplastic fiber batting. This composite structure achieves puncture resistance equivalent to steel while maintaining flexibility and comfort, as the layered composite can deform and conform to foot movement unlike rigid steel plates
Solution Approach 2:
The patent changes the physical parameters of the protective material by using high-density polypropylene fibers with specific tensile strength properties and controlling the density of the thermoplastic batting. The heat treatment process further modifies the material parameters by melting and bonding the thermoplastic fibers to the woven fabric, creating a unified composite structure with optimized mechanical properties
2Strength
If steel plate is used for shoe sole protection, then puncture resistance is improved, but weight and thickness increase
Solution Approach 1:
The patent employs lightweight polypropylene-based materials that can be mass-produced at low cost and provide adequate protective performance for the intended application lifecycle. The thermoplastic fiber batting and woven fabric combination offers sufficient puncture resistance without the excessive weight of steel, making it suitable for consumer footwear where weight sensitivity is high
Solution Approach 2:
The composite structure of woven fabric and thermoplastic batting achieves steel-level puncture resistance with fraction of the weight, as the layered architecture distributes and absorbs puncture forces across multiple interfaces rather than relying on dense metallic material
3Ease of operation
If fabric composite is used for shoe sole protection, then flexibility is improved, but puncture resistance deteriorates
Solution Approach 1:
The patent creates a composite material system where woven polypropylene fabric provides structural integrity and flexibility, while embedded thermoplastic fiber batting provides puncture resistance. The combination achieves both flexibility for comfort and sufficient puncture protection, overcoming the limitations of single-material fabric composites
Solution Approach 2:
The patent applies different material properties to different functional requirements: the woven fabric layers provide flexibility and conformability in areas requiring movement, while the denser thermoplastic fiber batting provides localized puncture resistance where needed, creating a spatially differentiated protective structure
4Strength
If density is increased through heat treatment and calendaring, then puncture resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses heat treatment to change the physical state of thermoplastic fibers, melting them to bond with the woven fabric and increase material density. This parameter change approach achieves enhanced puncture resistance through a relatively simple thermal processing step rather than complex mechanical consolidation equipment
Solution Approach 2:
The patent replaces complex mechanical compression or bonding systems with a simpler thermal field approach. By heating the thermoplastic fibers above their melting point and then cooling them, the material self-bonds to the woven fabric and densifies, eliminating the need for sophisticated mechanical pressing or adhesive application equipment
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 resulting material provides enhanced puncture resistance and flexibility while maintaining a low weight and suitable thickness, passing ASTM standards for both properties, making it suitable for shoe soles and other protective applications.
Implementation Method 1
The consolidated material is heated above the glass transition temperature of the fibers to thermally shrink the fibers thus increasing the density of the material
Implementation Method 2
needlepunching the batting material in a perpendicular direction into the woven layer to form a consolidated material
Data Source
AI summary
A puncture resistant material is made from high modulus continuous filament polypropylene yarns which are twisted and woven into a tight weave. Batting materials are placed adjacent the woven layer (which may comprise one or more individual woven layers) to form a stack and the stack is needlepunched to form a consolidated material. The material is heat treated and calendared and the finished product may be used in applications where puncture resistance is required, such as in a shoe insole material.