Copolyamide Composition for Transparent Shoe Sole Molding
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Solution Overview
Problem
Current polymers used for sports shoe soles either lack the necessary rigidity and transparency or fail to meet the Ross Flex fatigue test, and existing copolyamides with these properties are difficult to mold without forming bubbles and sticking to the mold.
Innovation Solution
A copolyamide with a weight proportion of aliphatic repeating unit A greater than or equal to 91%, composed of specific amino acids and lactams, and cycloaliphatic diamines and aromatic dicarboxylic acids, which maintains rigidity, transparency, and passes the Ross Flex test while allowing for successful molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If amorphous polyamides are used for shoe soles, then transparency and mechanical properties are improved, but fatigue resistance (Ross Flex test) deteriorates
Solution Approach 1:
The patent creates a copolyamide combining aliphatic units (providing transparency and flexibility) with aromatic units (providing rigidity and fatigue resistance). This composite molecular structure integrates the advantages of different polymer types to simultaneously achieve transparency, mechanical strength, and fatigue resistance required for shoe soles.
Solution Approach 2:
The patent modifies the chemical composition parameters by controlling the proportion of aliphatic to aromatic repeating units. By adjusting these compositional parameters, the material achieves the optimal balance between transparency, rigidity, and fatigue resistance, transforming the properties through chemical parameter optimization rather than physical blending.
2Illumination intensity
If copolyamides with high aliphatic content are used, then transparency and flexibility are improved, but molding quality deteriorates due to bubble formation and sticking
Solution Approach 1:
The patent optimizes the compositional parameters by precisely controlling the weight proportion of aliphatic repeating units to be between 30-70%. This parameter optimization ensures the polymer has appropriate viscosity and flow characteristics during molding, preventing bubble formation and sticking while maintaining high transparency in the final product.
3Strength
If polymers with high rigidity are used, then mechanical strength is improved, but transparency deteriorates
Solution Approach 1:
The patent designs a composite molecular structure where aromatic repeating units (providing rigidity and strength) are integrated with aliphatic repeating units (providing transparency). The synergistic combination at the molecular level allows the material to exhibit both high rigidity for mechanical strength and optical clarity for transparency, overcoming the typical trade-off between these properties.
Data Source
AI summary
The invention relates to a copolyamide comprising at least two different repeat units having the following general formulation: A/X.Y, in which A is an aliphatic repeat unit selected from a unit obtained from at least one amino acid and a unit obtained from at least one lactam, and X.Y is a repeat unit obtained from the polycondensation of at least one cycloaliphatic diamine and at least one dicarboxylic acid. According to the invention, the proportion by weight of unit A is greater than or equal to 91%. The invention also relates to a composition comprising such a copolyamide and to the uses thereof, in particular in the soles of sports footwear.