High-Molecular-Weight Rosin Ester Rubber Composition for Tire Processability
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Solution Overview
Problem
Current rubber compositions for Ultra High Performance (UHP) and summer tires face challenges with processability issues such as tackiness, high viscosity, and lack of green strength, which compromise properties like wet grip, rolling resistance, and tire wear, leading to a trade-off between processing properties and performance criteria.
Innovation Solution
A rubber composition incorporating a higher-molecular-weight rosin ester, prepared with rosin having an acid number of 130 to 190 mg KOH/g and an alcohol with a molecular weight of at least 200 g/mol and not more than seven hydroxyl groups, improves the Mooney viscosity and enhances tire properties like grip, wear, and rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high proportion of resin is added to improve tyre grip and wear resistance, then tyre performance is improved, but processability deteriorates due to increased viscosity and tackiness
Solution Approach 1:
The patent changes the molecular weight parameter of the rosin ester additive from conventional lower molecular weights to higher molecular weights (≥200 g/mol), which fundamentally alters the additive's behavior in the rubber compound. This parameter change allows the additive to provide adequate lubrication and processing aid functionality while having reduced adverse effects on the final tyre performance properties, thus resolving the contradiction between processability and tyre performance.
2Ease of manufacture
If processing aids are used to improve processability, then manufacturing ease is improved, but tyre performance deteriorates due to lower stiffness and increased wear
Solution Approach 1:
The patent applies the local quality principle by using a higher molecular weight rosin ester that exhibits different functional characteristics at different stages: during mixing and processing, it provides adequate lubrication and processability improvement, while in the final vulcanized tyre, it has minimal negative impact on stiffness and wear resistance. The higher molecular weight ensures the additive remains primarily in the processing phase rather than migrating into the final product structure.
3Ease of manufacture
If conventional rosin ester additives are used to improve processability, then manufacturing ease is improved, but tyre performance deteriorates due to poorer handling and increased rolling resistance
Solution Approach 1:
The patent changes the molecular weight parameter of the rosin ester additive from conventional lower molecular weights to higher molecular weights (≥200 g/mol), which fundamentally alters the additive's behavior in the rubber compound. This parameter change allows the additive to provide adequate lubrication and processing aid functionality while having reduced adverse effects on the final tyre performance properties, thus resolving the contradiction between processability and tyre performance.
Data Source
AI summary
The present invention relates to a rubber composition containing rubber and at least one rubber additive based on a higher molecular weight colophony rosin ester. The at least one rubber additive comprises colophony rosin ester made from colophony rosin and at least one alcohol, wherein the colophony rosin used for producing the colophony rosin ester has an acid number of 130 to 190 mg KOH/g and the at least one employed alcohol has not more than seven hydroxyl groups and a molecular weight of at least 200 g/mol. The present invention further relates to the use of the rubber additive in a rubber composition, to a tire, where at least one component part is at least partially produced from the rubber composition according to the invention, and to processes for the production thereof.