Guayule Rubber Tire Tread with Hydrocarbon Resin
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Solution Overview
Problem
The tire industry faces challenges in using guayule natural rubber in passenger tire treads due to its low glass transition temperature (Tg), which limits wet traction characteristics without compromising rolling resistance or wear, and existing additives fail to effectively raise Tg without adverse effects.
Innovation Solution
Incorporating a hydrocarbon resin into guayule natural rubber tread compounds, with specific resins like cycloaliphatic and aliphatic hydrocarbon resins, to increase the Tg while maintaining compatibility and minimizing resin usage, thereby enhancing wet traction without affecting rolling resistance or wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional processing oils are used to compound pure natural rubber, then the Tg is lowered, but wet traction characteristics deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the elastomer system by incorporating guayule natural rubber (which has a higher Tg of approximately -50°C) instead of conventional natural rubber or synthetic rubbers. This parameter change in the elastomer's molecular structure and composition enables achieving a higher Tg while maintaining wet traction characteristics, resolving the contradiction between Tg and wet traction performance
Solution Approach 2:
The patent creates a composite elastomer system combining guayule natural rubber with specific synthetic rubber components (SBR and/or BR) in controlled ratios. This composite approach allows optimization of the overall Tg and wet traction properties by leveraging the complementary characteristics of different rubber types, achieving both high Tg and good wet traction that neither component could achieve alone
2Quantity of substance
If more natural rubber is used in passenger tire compounds, then cost is reduced, but Tg decreases and wet traction deteriorates
Solution Approach 1:
The patent changes the source and composition parameters of the natural rubber by using guayule-derived natural rubber instead of conventional Hevea natural rubber. Guayule natural rubber has inherently higher Tg properties, so increasing its quantity in the compound simultaneously achieves both cost reduction and Tg improvement, eliminating the trade-off between quantity and temperature characteristics
3Temperature
If additives are used to raise the Tg of guayule natural rubber, then wet traction is improved, but rolling resistance and wear may be adversely affected
Solution Approach 1:
The patent extracts and eliminates the need for Tg-raising additives by using guayule natural rubber as the primary elastomer component. The inherent high Tg properties of guayule natural rubber provide the desired wet traction performance without requiring additional chemical additives that could compromise rolling resistance or wear properties, thus resolving the contradiction through removal of harmful elements
Data Source
AI summary
A tire tread composition includes a quantity of an elastomer including guayule natural rubber, and a quantity of a hydrocarbon resin substantially evenly distributed throughout the elastomer. The elastomer of the tire tread composition may consist entirely of guayule natural rubber. The hydrocarbon resin may be selected to have a predetermined miscibility in the guayule natural rubber. The predetermined miscibility is measured by a deviation of actual Tg from predicted Tg for either the tire tread composition or an elastomer-resin mixture consistent with the elastomer and resin used in the tire tread composition. In particular, the predetermined miscibility in the guayule natural rubber is less than about six percent (6%) deviation in the actual Tg from the predicted Tg at a 20 phr loading.