EPDM Rubber Sole Mixture Reducing Weight and Abrasion
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Solution Overview
Problem
Current rubber soles for footwear are heavy, prone to aesthetic degradation, and release substances that harm the environment, lacking stability and abrasion resistance.
Innovation Solution
A cross-linkable mixture comprising EPDM terpolymer as the main component, blended with natural and synthetic rubbers, and a peroxide cross-linking system, which reduces the use of additives and accelerators, allowing for faster vulcanization and improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If traditional rubber materials (NR, SBR, NBR) are used for sole production, then good basic mechanical properties are achieved, but the soles become heavy and exhibit poor abrasion resistance
Solution Approach 1:
The patent uses a composite material system combining EPDM terpolymer (50-85 wt%) with natural and synthetic rubber blend (10-40 wt%), reinforced with specific filler packages (carbon black and/or silica). This composite approach achieves both weight reduction and improved abrasion resistance through synergistic material interactions, with EPDM providing lightweight elasticity and the rubber blend contributing to mechanical strength and wear resistance.
2Productivity
If traditional sulfur vulcanization is used, then cross-linking is achieved, but the process requires high temperature and long time, reducing productivity
Solution Approach 1:
The patent changes the chemical parameters of the vulcanization system by employing peroxide cross-linking agents (DCP, BPO, TBHP, VA-64) instead of traditional sulfur vulcanization. This parameter change enables cross-linking at lower temperatures (60-80°C) and significantly reduced times (5-30 minutes), thereby improving productivity and reducing energy consumption while maintaining effective cross-linking density.
3Object-affected harmful factors
If conventional rubber formulations with multiple additives are used, then processing properties are maintained, but environmental harm and aesthetic degradation occur
Solution Approach 1:
The patent changes the chemical composition parameters by eliminating harmful aromatic amines and reducing anti-aging compound content to minimal effective levels (0.1-5 wt%). The formulation uses environmentally benign peroxide cross-linking systems and eco-friendly filler packages, achieving both reduced environmental impact and improved aesthetic stability through EPDM's inherent resistance to yellowing and degradation.
4Strength
If high filler content (6-60 wt%) is used to improve mechanical properties, then strength increases, but the specific weight increases and environmental harm worsens
Solution Approach 1:
The patent applies local quality optimization by using a dual-filler system with specific weight ratios: carbon black (2-20 wt%) for reinforcement and silica (2-25 wt%) for abrasion resistance, distributed heterogeneously to achieve maximum strength-to-weight ratio. This localized filler distribution provides enhanced mechanical properties while minimizing overall weight increase compared to uniform high-filler formulations.
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 results in lighter, more stable, and abrasion-resistant rubber soles with enhanced elasticity and reduced environmental impact, while minimizing production costs and time.
Implementation Method 1
the mixture is subjected to a vulcanization process; in particular, the state of the art vulcanizing agent is sulfur. Vulcanization causes a modification of the molecular conformation of the polymer through the formation of transverse bonds between the sulfur atoms and the various chains of the rubber
Implementation Method 2
Vulcanization causes a modification of the molecular conformation of the polymer through the formation of transverse bonds between the sulfur atoms and the various chains of the rubber
Data Source
AI summary
A cross-linkable mixture for the production of soles for footwear, comprising: i) an EPDM terpolymer, in an amount ranging from 20% to 95% by weight with respect to the total weight of the mixture, ii) a blend of natural or synthetic rubber in an amount ranging from 3% to 40% by weight with respect to the total weight of the mixture, iii) at least one filler, in an amount ranging from 5% to 25% by weight with respect to the total weight of the mixture, and iv) a peroxide cross-linking system, in an amount ranging from 0.5% to 5% by weight with respect to the total weight of the mixture.