Polyolefin-Based Footwear Sole Structures for Chunking Resistance
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Solution Overview
Problem
Existing polyolefin-based resins used in footwear and sporting equipment suffer from poor mechanical properties, such as susceptibility to scratching, fracturing, and 'chunking', as well as stress whitening under cold conditions, leading to reduced durability and appearance issues.
Innovation Solution
Combining a thermoplastic vulcanizate (TPV) with a polyolefin copolymer and a polymeric resin modifier, particularly a propylene-ethylene copolymer, to create a polyolefin-based resin composition that enhances durability and resistance to cracking and fracturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyolefin-based resin is used to reduce cost and improve recyclability, then manufacturing cost and environmental sustainability are improved, but mechanical durability and resistance to scratching and fracturing deteriorate
Solution Approach 1:
The patent applies composite materials by combining polyolefin copolymer with thermoplastic vulcanizate (TPV) and polymeric resin modifier. This creates a multi-component system where the polyolefin copolymer provides base structure and cost-effectiveness, while the TPV (crosslinked elastomer in thermoplastic matrix) contributes toughness and crack resistance, and the resin modifier enhances flexibility and stress distribution. This composite approach maintains the cost and recyclability advantages of polyolefin while significantly improving mechanical durability and resistance to scratching and fracturing.
Solution Approach 2:
The patent employs parameter changes by modifying the molecular structure and physical properties of the polyolefin resin through controlled copolymerization and addition of functional additives. The resin composition parameters (molecular weight distribution, crystallinity, crosslink density) are optimized to achieve a balance between cost-effectiveness and mechanical performance. The TPV content and resin modifier concentration are adjusted to transform the brittle characteristics of pure polyolefin into a more durable, flexible material.
2Adaptability or versatility
If polyolefin-based resin is used to improve recyclability, then environmental sustainability is improved, but resistance to stress whitening and cracking under cold conditions deteriorates
Solution Approach 1:
The composite material system addresses cold-condition durability by incorporating TPV, which contains crosslinked elastomer domains that remain flexible at low temperatures. The elastomeric phase prevents stress concentration and crack propagation in cold environments, while the thermoplastic matrix maintains processability and recyclability. The resin modifier further enhances low-temperature flexibility and prevents stress whitening by improving stress distribution throughout the material structure.
Solution Approach 2:
The patent modifies the thermal and mechanical parameters of the polyolefin resin through controlled formulation. The glass transition temperature (Tg) and crystallinity are adjusted to ensure flexibility and crack resistance at cold temperatures. The crosslink density in the TPV component is optimized to provide low-temperature toughness while maintaining recyclability through controlled thermal processing windows.
3Ease of manufacture
If polyolefin-based resin is used to reduce material cost, then manufacturing cost is improved, but resistance to scratching and fracturing deteriorates
Solution Approach 1:
The patent creates a cost-effective durable material by combining inexpensive polyolefin copolymer with relatively small amounts of TPV and resin modifier. The polyolefin copolymer provides the bulk material at low cost, while the TPV (crosslinked elastomer) contributes scratch and fracture resistance through its tough, crack-resistant network. The resin modifier enhances surface hardness and scratch resistance. This composite structure achieves high scratch and fracture resistance at a lower material cost than using traditional high-performance polymers alone.
Solution Approach 2:
The patent optimizes the compositional parameters of the resin system to maximize durability per unit cost. The molecular weight distribution, crystallinity, and crosslink density are controlled to achieve optimal hardness and fracture resistance. The ratio of TPV to polyolefin copolymer is optimized to provide maximum scratch and fracture resistance at minimum material cost, creating a cost-effective solution that outperforms pure polyolefin in durability.
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 resin composition exhibits improved mechanical properties, including resistance to 'chunking' and stress whitening, making it suitable for use in footwear and sporting equipment components.
Implementation Method 1
combining a thermoplastic vulcanizate (TPV) with a polyolefin copolymer and a polymeric resin modifier, particularly a propylene-ethylene copolymer, to create a polyolefin-based resin composition that enhances durability and resistance to cracking and fracturing
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1F
AI summary
Sole structures for footwear (110) are provided, the sole structure having a first side and a second side, wherein the first side which is configured to be ground-facing includes a plurality of traction elements (118), the sole structure including polyolefin-based resin compositions comprising a polyolefin copolymer, a polymeric resin modifier and a thermoplastic vulcanizate (TPV). Articles of footwear (110) including the sole structures are also provided.