Co-Cured Tire Tread Composition for HSBR Delamination Control
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Solution Overview
Problem
Hydrogenated styrene-butadiene rubber (HSBR) has limited co-curability with non-hydrogenated rubbers, leading to reduced tear strength and shorter tire tread life due to delamination, which affects the performance and durability of tires.
Innovation Solution
A tire composition that includes a first rubber component with 70-100 phr of hydrogenated styrene butadiene rubber and a second rubber component with non-hydrogenated diene-based rubbers, such as polybutadiene or polyisoprene, along with a polyoctenamer, which improves co-curability and reduces hysteresis, resulting in better fuel economy and extended tire life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hydrogenated styrene butadiene rubber is used to improve tensile properties and oxidative degradation resistance, then tensile strength and durability are improved, but co-curability with non-hydrogenated rubbers deteriorates leading to delamination
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance between the hydrogenated styrene butadiene rubber and non-hydrogenated rubber components. The silane coupling agent contains both hydrolyzable groups that react with the hydrogenated rubber and organic groups that are compatible with non-hydrogenated rubbers, thereby mediating the interface and improving co-curability while maintaining the tensile strength benefits of hydrogenated rubber.
Solution Approach 2:
The invention creates a composite rubber system where hydrogenated styrene butadiene rubber, non-hydrogenated rubber components, and silane coupling agent form a multi-phase composite material. This composite structure allows each component to contribute its advantageous properties while the silane coupling agent ensures strong interfacial bonding between the incompatible rubber phases.
2Duration of action of stationary object
If hydrogenated styrene butadiene rubber is used to improve oxidative degradation resistance, then service life is extended, but adhesion to non-hydrogenated rubber components deteriorates
Solution Approach 1:
The silane coupling agent serves as a mediator that bridges the hydrogenated rubber (providing oxidative degradation resistance) and non-hydrogenated rubber components (requiring good adhesion). The coupling agent's dual chemistry allows it to bond with both rubber types, ensuring strong adhesion while preserving the long service life benefits of hydrogenated rubber.
Solution Approach 2:
The invention changes the chemical parameters at the rubber-rubber interface by introducing silane groups that can undergo hydrolysis and condensation reactions. This parameter change creates a chemically active interface that enhances adhesion between the hydrogenated and non-hydrogenated rubber components, while the bulk properties of hydrogenated rubber continue to provide oxidative degradation resistance.
3Reliability
If polyoctenamer is added to improve co-curability, then adhesion between rubber components is improved, but hysteresis increases leading to higher rolling resistance
Solution Approach 1:
The invention optimizes the molecular weight and chemical structure parameters of the polyoctenamer to achieve the right balance. By controlling these parameters, the polyoctenamer provides sufficient co-curability improvement through enhanced interfacial bonding while minimizing the increase in hysteresis that would lead to higher rolling resistance.
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 tire composition enhances tear strength, reduces rolling resistance, and improves durability, leading to better fuel economy and extended tire service life by improving the co-curability of hydrogenated and non-hydrogenated rubber components.
Implementation Method 1
the first rubber component is cured (co-cured) to the second rubber component
Implementation Method 2
the level of hysteresis exhibited is reduced. A reduced level of hysteresis is indicative of reduced tire rolling resistance
Data Source
AI summary
The present invention is directed a tire comprising two rubber components which are co-cured together. The first rubber component comprises from 70 phr to 100 phr of a hydrogenated styrene butadiene rubber, 0 phr to 15 phr of a polybutadiene, 5 phr to 20 phr of a polyoctenamer, and 40 phr to 160 phr of a first filler. The second rubber component comprises 90 phr to 100 phr of a diene-based elastomer; and 20 phr to 160 phr of a second filler. Moreover, the present invention is directed to a rubber composition comprising a hydrogenated styrene butadiene rubber, 5 phr to 20 phr of a polyoctenamer, and 40 phr to 160 phr of a reinforcing filler.