Rubber Composition Kneading Sequence for Mercapto Silane Processability
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Solution Overview
Problem
Existing rubber composition methods using silane coupling agents with mercapto groups face challenges in processability due to high reactivity, leading to gelling and degradation of mechanical strength, which affects rolling resistance, fuel efficiency, and performance of tires.
Innovation Solution
A manufacturing method involving a specific sequence of kneading steps with a rubber component having a lower activating ability with respect to the mercapto group, a compound represented by Formula (1), and a silane coupling agent, where the compound is kneaded first to reduce radicalization and prevent gelling, followed by kneading with the second rubber component having a higher activating ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a silane coupling agent having a mercapto group is used to improve low fuel consumption and wet grip performance, then fuel efficiency and grip performance are improved, but the mercapto silane coupling agent gels during kneading and processability deteriorates
Solution Approach 1:
The patent applies preliminary action by introducing a radical-generating step before the kneading process. The radical initiator is added and activated prior to incorporating the mercapto silane coupling agent, which generates radicals that prevent the mercapto groups from crosslinking during kneading. This preliminary radical generation creates a protective environment that maintains processability while preserving the low fuel consumption and wet grip benefits of the mercapto silane coupling agent
2Strength
If a mercapto silane coupling agent is kneaded with rubber components to achieve low fuel consumption and wear resistance, then fuel efficiency and wear resistance are improved, but gelling occurs and processability is deteriorated
Solution Approach 1:
The patent uses radical initiators as intermediaries to mediate between the mercapto silane coupling agent and the rubber components. The radical initiator acts as a mediator that generates radicals to occupy the mercapto groups, preventing them from crosslinking with the rubber during kneading. This intermediary mechanism allows the mercapto silane coupling agent to maintain its wear resistance properties without causing gelling and processability deterioration
3Productivity
If all rubber components are kneaded with silane coupling agent and zinc dithiophosphate in the same process step, then manufacturing simplicity is maintained, but processability can be further improved by sequential kneading
Solution Approach 1:
The patent applies segmentation by dividing the kneading process into multiple sequential steps. First, the radical initiator is added and activated; second, the mercapto silane coupling agent is incorporated under controlled conditions; third, the rubber components are mixed. This segmented approach to the manufacturing process improves processability by preventing gelling, while the overall sequential nature maintains reasonable manufacturing efficiency
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
This method improves the processability of unvulcanized rubber, maintaining performance enhancements such as low fuel consumption, wet grip, and wear resistance while preventing gelling, thereby enhancing the overall tire manufacturing process.
Implementation Method 1
a mercapto silane coupling agent may gel while kneaded with rubber components or the like due to its high reactivity
Implementation Method 2
crosslinking between polymers can be made more uniform by a predetermined kind of zinc dithiophosphate being blended
Implementation Method 3
crosslinking between polymers can be made more uniform by a predetermined kind of zinc dithiophosphate being blended
Data Source
AI summary
Provided are a method for manufacturing a rubber composition for a tire and a tire manufacturing method that allow good processability to be obtained also when a silane coupling agent having a mercapto group is blended. A method, for manufacturing a rubber composition, for a tire, which contains a rubber component (A) having at least two kinds of rubber components, a compound (B) represented by Formula (1), and a silane coupling agent (C) having a mercapto group, includes: a step X1 of kneading a first rubber component of the rubber component (A) and the compound (B); a step X2 of kneading the silane coupling agent (C) with a kneaded product obtained in the step X1; and a step X3 of kneading a second rubber component of the rubber component (A) with a kneaded product obtained in the step X2. In the method, the first rubber component has a lower activating ability with respect to a mercapto group than the second rubber component. The tire manufacturing method includes the method for manufacturing the rubber composition. (In the Formula, R1 to R4 each independently represent a predetermined group.)