Ethylene-Diene Rubber Composition With Polyethylene for Low Hysteresis
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Solution Overview
Problem
Rubber compositions for tire internal layers face challenges in achieving high stiffness while reducing hysteresis and eliminating the need for reinforcing resins, which typically increase hysteresis and have environmental concerns due to formaldehyde release.
Innovation Solution
A rubber composition based on an elastomer matrix with over 50 phr of a copolymer containing ethylene and diene units, combined with 0 to 50 phr of reinforcing filler and at least 3 phr of polyethylene, and a crosslinking system, which replaces conventional reinforcing fillers and resins, thereby reducing hysteresis and maintaining or improving stiffness and elongation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large amounts of reinforcing fillers are introduced into rubber compositions to obtain high stiffness, then stiffness is improved, but hysteresis increases and rolling resistance worsens
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber matrix by using a specific copolymer with controlled ethylene-diene ratio and incorporating polyethylene at 3-50 phr. This compositional parameter change enables achieving high stiffness (up to 80% of steel belt stiffness) while maintaining low hysteresis, as the polyethylene-modified matrix provides structural rigidity without the energy losses associated with traditional filler-rubber interactions
Solution Approach 2:
The patent creates a composite rubber composition by combining the copolymer matrix with polyethylene and a crosslinking system. This composite approach, where polyethylene acts as a reinforcing agent within the rubber matrix, achieves the desired stiffness-hysteresis balance by leveraging the complementary properties of the different materials rather than relying solely on traditional fillers
2Strength
If reinforcing resins such as phenoplast resins are used to increase stiffness, then stiffness is improved, but hysteresis increases and limiting properties degrade
Solution Approach 1:
The patent extracts and eliminates reinforcing resins from the composition entirely, replacing their stiffening function with a combination of polyethylene and crosslinking system. This removal of harmful resins not only reduces hysteresis but also eliminates formaldehyde release, while the polyethylene-copolymer matrix maintains the necessary mechanical properties through alternative mechanisms
Solution Approach 2:
The patent replaces expensive, environmentally problematic reinforcing resins with a simpler, more sustainable combination of polyethylene and crosslinking agents. This substitution uses readily available, environmentally friendly materials that achieve the same functional outcome without the harmful side effects
3Loss of energy
If reinforcing fillers are reduced or eliminated to lower hysteresis, then hysteresis is improved, but stiffness decreases
Solution Approach 1:
The patent changes the matrix composition parameters by incorporating polyethylene at 3-50 phr into the copolymer system and optimizing the crosslinking density. This parameter modification allows the rubber matrix itself to provide sufficient stiffness (comparable to or exceeding traditional filled compositions) while maintaining low filler content and thus low hysteresis
Solution Approach 2:
The patent discards the traditional approach of relying on high filler loading for stiffness and recovers the stiffening function through the polyethylene-copolymer matrix system. The matrix itself, when properly formulated and crosslinked, recovers the structural support function previously provided by fillers, enabling low-filler or filler-free compositions with adequate stiffness
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 significantly reduces hysteresis and maintains or improves stiffness and elongation at break, addressing the limitations of traditional compositions without using reinforcing resins, thus enhancing the mechanical properties of tire internal layers.
Implementation Method 1
an elastomer matrix containing more than 50 phr of at least one copolymer containing ethylene units and diene units
Implementation Method 2
on a crosslinking system
Data Source
AI summary
A rubber composition exhibits high stiffness, without using high amounts of reinforcing filler or without using reinforcing resins, while at the same time possesses improved limiting properties. This composition is based on at least one elastomer matrix containing more than 50 phr of at least one copolymer containing ethylene units and diene units, on from 0 to 50 phr of reinforcing filler, on at least 3 phr of a polyethylene and on a crosslinking system.