Polypropylene Outsole Composition for Slip Resistance and Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polypropylene-based shoe outsoles suffer from high hardness, poor slip resistance, and difficulty in adhering to other footwear components without using adhesives, which complicates recycling.
Innovation Solution
A polypropylene-based outsole material comprising a polypropylene homopolymer (5-25 wt%), a thermoplastic polypropylene copolymer (70-87 wt%), and a maleic anhydride-grafted polyolefin elastomer modifier (0-10 wt%), allowing direct bonding to a midsole via a foaming process without adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polypropylene is used to make outsole, then cost is reduced and durability is improved, but hardness increases and slip resistance deteriorates
Solution Approach 1:
The patent uses a composite material system consisting of polypropylene homopolymer (5-25 wt%), thermoplastic polypropylene copolymer (70-87 wt%), and maleic anhydride-grafted polyolefin elastomer modifier (0-10 wt%). This composite formulation allows the outsole to achieve both durability from the polypropylene base and improved slip resistance from the elastomer modifier, resolving the contradiction between strength and ease of operation.
2Ease of manufacture
If polypropylene is used to make outsole, then manufacturing simplicity is maintained, but adhesion to midsole deteriorates without adhesive
Solution Approach 1:
The maleic anhydride-grafted polyolefin elastomer modifier provides self-adhesive functionality to the polypropylene outsole, enabling direct bonding to the midsole without requiring separate adhesive applications. This maintains manufacturing simplicity while achieving the necessary adhesion strength through the modifier's inherent bonding capabilities.
3Strength
If adhesive is used to bond outsole to midsole, then adhesion is improved, but recyclability deteriorates
Solution Approach 1:
The patent extracts and eliminates the need for adhesive by incorporating bonding functionality directly into the polypropylene outsole material through the maleic anhydride-grafted polyolefin elastomer modifier. This allows the outsole to bond directly to the midsole without adhesive, thereby maintaining adhesion strength while improving recyclability by removing the adhesive layer that would complicate separation and recycling processes.
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 solution provides a polypropylene outsole with appropriate hardness, high slip resistance, and strong bonding to the midsole, facilitating easy recycling and reducing environmental impact.
Implementation Method 1
a midsole made of a midsole material including a polyolefin elastomer, the midsole being bonded onto a surface of the outsole by subjecting the midsole material to a foaming process, followed by solidification
Data Source
AI summary
A polypropylene-based outsole material, which includes, based on 100 wt % of the polypropylene-based outsole material, a polypropylene homopolymer present in an amount ranging from 5 wt % to 25 wt %, a thermoplastic polypropylene copolymer present in an amount ranging from 70 wt % to 87 wt %, and a modifier present in an amount greater than 0 wt % and not greater than 10 wt %. The modifier is a maleic anhydride-grafted polyolefin elastomer. A footwear sole structure including an outsole made of the polypropylene-based outsole material, and a footwear article including the footwear sole structure are also provided.