Low-Density Polyurethane Shoe Soles with High Rebound Resilience
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Solution Overview
Problem
Current methods for producing polyurethane shoe soles with low densities (100 to 350 g/L) face challenges in achieving uniform mechanical properties, particularly high rebound resilience and low compression set, due to irregular cell morphology and high costs associated with specific polyols and processes.
Innovation Solution
A process involving the reaction of organic polyisocyanates, polyols, a blowing agent (water), and optional crosslinking agents, where a prepolymer is formed at 110° C to 180° C, and then further reacted with remaining components in a mold to produce a polyurethane foam that can be shaped into shoe soles with improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If polyurethane shoe soles are produced with low densities (100 to 350 g/L), then the weight of the shoe sole is reduced, but the cell morphology becomes irregular and mechanical properties become nonuniform
Solution Approach 1:
The patent applies preliminary action by pre-mixing polyisocyanate, polyol, and crosslinking agent before introducing the blowing agent. This ensures uniform distribution of reactants and controlled foam formation, resulting in regular cell morphology and uniform mechanical properties even at low densities of 100 to 350 g/L
Solution Approach 2:
The patent utilizes parameter changes by controlling the reaction temperature (110°C to 180°C) and adjusting the ratio of components to achieve optimal foam structure. This enables production of low-density shoe soles with uniform cell morphology and consistent mechanical properties
2Weight of moving object
If conventional polyurethane foam is used with low densities, then the weight is reduced, but rebound resilience declines severely
Solution Approach 1:
The patent employs composite materials by combining polyisocyanate, polyol, and crosslinking agent in specific ratios to create a polyurethane foam with enhanced rebound resilience. The crosslinking agent forms a three-dimensional network structure that maintains elasticity and rebound properties even at low densities
Solution Approach 2:
The patent applies parameter changes by optimizing the reaction temperature (110°C to 180°C) and component ratios to achieve a foam structure with high rebound resilience. The controlled reaction conditions produce uniform cell structure that maintains mechanical performance at low densities
3Strength
If specific polyols are used to improve mechanical properties, then rebound resilience and compression set improve, but production cost increases
Solution Approach 1:
The patent applies parameter changes by optimizing the reaction temperature (110°C to 180°C) and component ratios to achieve high rebound resilience and low compression set using conventional, cost-effective polyols. This eliminates the need for expensive specific polyols while maintaining superior mechanical properties
Solution Approach 2:
The patent uses cost-effective conventional polyols instead of expensive specific polyols, achieving the same mechanical performance through optimized process parameters. The crosslinking agent and controlled reaction conditions compensate for the use of cheaper materials
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 process results in polyurethane shoe soles with high rebound resilience, low compression set, and cost-effective production, achieving densities of 100 to 350 g/L with enhanced mechanical properties such as hardness, tensile strength, and elongation.
Implementation Method 1
a first step comprises polyisocyanate (a), polyol (b) and any crosslinking and/or chain-extending agent (d) being mixed and reacted at a temperature of 110° C. to 180° C. to give a prepolymer having polyisocyanate groups
Implementation Method 2
a second step comprises the isocyanate-terminated prepolymer obtained and any remaining polyisocyanate (a) being mixed with any remaining polyol (b), blowing agent comprising water (c), and any remaining crosslinking and/or chain-extending agent (d) and also any catalyst (e) and other auxiliaries and/or additives (f), being introduced into a mold and allowed to fully react to give a polyurethane shoe sole
Implementation Method 3
a blowing agent comprising water (c)
Implementation Method 4
blowing agent comprising water (c)
Data Source
AI summary
A process for producing a polyurethane shoe sole having an article density of 100 to 350 g/L and being made from an organic polyisocyanate, a polyol, a blowing agent consisting of water, and optionally a crosslinking and/or chain-extending agent, a catalyst, and other auxiliaries and/or additives. First, polyisocyanate, polyol and any crosslinking and/or chain-extending agent are mixed and reacted at a temperature of 110° C. to 180° C. to give a prepolymer having polyisocyanate groups. Second, the isocyanate-terminated prepolymer obtained and any remaining polyisocyanate are mixed with any remaining polyol, blowing agent comprising water, and any remaining crosslinking and/or chain-extending agent and also any catalyst and other auxiliaries and/or additives are introduced into a mold and allowed to fully react to give a polyurethane shoe sole.