Polyolefin Elastomer Foam with Crosslinked Network for High Rebound
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Solution Overview
Problem
Current foaming technologies in footwear applications typically achieve a rebound of only 60-65%, which is below the desired level of 70%, and struggle to maintain low foam density while ensuring good mechanical properties.
Innovation Solution
A high energy return foam is developed using a composition comprising 30 wt % to 100 wt % of a polyolefin elastomer with specific density and melt index (MI) ranges, combined with 0 wt % to 70 wt % of a polyolefin derivative, which is crosslinked and then foamed to achieve the desired properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional foaming technology is used, then foam can be produced, but rebound is limited to 60-65% and cannot reach the desired 70%
Solution Approach 1:
The patent applies parameter changes by precisely controlling the density (0.857-0.884 g/cc) and melt index (≤5 g/10 min) of the polyolefin elastomer, as well as the composition ratios of polymer components. These specific parameter ranges enable the foam to achieve rebound ≥70% while maintaining manufacturability through crosslinking and foaming processes.
Solution Approach 2:
The patent uses composite materials by combining polyolefin elastomer with specific polyolefin derivatives in defined weight ratios (30-100 wt% elastomer + 0-70 wt% derivative). This composite approach allows the foam to simultaneously achieve high rebound, low density, and good mechanical properties that cannot be obtained with single polymers.
2Reliability
If foam density is reduced to achieve low density foam, then energy return improves, but mechanical properties deteriorate
Solution Approach 1:
The patent changes parameters by optimizing the density range (0.857-0.884 g/cc) and melt index (≤5 g/10 min) of the polyolefin elastomer, and controlling the foaming process to achieve specific foam densities. These parameter optimizations enable the foam to simultaneously achieve high energy return (rebound ≥70%) and maintain good mechanical properties through the crosslinked network structure.
Solution Approach 2:
The patent employs composite materials consisting of polyolefin elastomer combined with polyolefin derivatives having specific density characteristics (less than 0.857 g/cc or greater than 0.884 g/cc). This composite structure allows the foam to achieve low overall density while the crosslinked network provides the necessary mechanical strength and energy return properties.
3Reliability
If polymer composition is optimized for high rebound, then processing difficulty increases
Solution Approach 1:
The patent applies parameter changes by specifying a melt index of not greater than 5 g/10 min for the polyolefin elastomer, which balances processability with final foam performance. This parameter control, combined with the defined density range (0.857-0.884 g/cc), enables both high rebound (≥70%) and reasonable processing conditions through crosslinking and foaming.
Solution Approach 2:
The patent uses composite materials where polyolefin elastomer (30-100 wt%) is combined with polyolefin derivatives (0-70 wt%). The derivative components can be selected to adjust processability while the elastomer provides the rebound characteristics. This composite approach allows optimization of both processing ease and final foam performance.
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 foam exhibits a rebound of not less than 70%, low density, and improved mechanical properties such as hardness, tensile strength, and elongation, while maintaining a high gel fraction and suitable processing conditions.
Implementation Method 1
crosslinking the polymers in the composition obtained in step a)
Implementation Method 2
foaming the resulting crosslinked polymers obtained in step b)
Data Source
AI summary
The present disclosure relates to a high energy return foam and method for preparing the same.