Rubber Composition Silica Dispersion Low Heat Generation
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Solution Overview
Problem
Current rubber compositions containing silica face challenges in achieving optimal low-heat-generation properties due to silica aggregation, despite the use of silane coupling agents, and there is a need for further enhancement in this area.
Innovation Solution
A rubber composition is developed with a specific dispersion state of silica, utilizing a rubber component, silica with a n-hexadecyltrimethylammonium bromide adsorption specific surface area of 140-180 m²/g, and a silane coupling agent, with an average aggregated aggregate area of silica reduced to 2,300 nm² or less through precise measurement and processing methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If silica is added to rubber composition to reduce rolling resistance, then low-heat-generation property is improved, but silica aggregation occurs due to hydroxyl groups on silica surface
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance between silica particles and rubber matrix. The silane coupling agent contains both hydrophilic groups that interact with silica surface hydroxyl groups and hydrophobic groups that interact with the rubber matrix, thereby preventing silica aggregation while maintaining low-heat-generation properties
Solution Approach 2:
The surface properties of silica are modified by controlling the CTAB adsorption specific surface area within a specific range (150-250 m²/g) and regulating the average aggregated aggregate area to 2,300 nm² or less. These parameter changes optimize the balance between preventing aggregation and maintaining low rolling resistance
2Stability of the object's composition
If silane coupling agent is used to prevent silica aggregation, then dispersion state is improved, but the activity of coupling function needs to be increased through various trials
Solution Approach 1:
The coupling efficiency is optimized by controlling specific parameters: the CTAB adsorption specific surface area of silica is maintained within 150-250 m²/g, and the average aggregated aggregate area is regulated to 2,300 nm² or less. These parameter specifications provide a clear guideline for achieving effective coupling without requiring extensive trial-and-error optimization
Solution Approach 2:
The complex process of optimizing coupling agent activity through multiple trials and measurements is replaced by establishing specific quantitative criteria (CTAB adsorption surface area and aggregate area thresholds). This substitution transforms an empirical optimization process into a more systematic approach based on defined parameters
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 composition exhibits improved low-heat-generation properties, as measured by reduced hysteresis properties (tanδ) and enhanced dispersion state, leading to better tire performance and reduced rolling resistance.
Implementation Method 1
silica aggregates (owing to the hydroxyl group in the surface of silica), and therefore, for preventing the aggregation, a silane coupling agent is used
Implementation Method 2
silica having a n-hexadecyltrimethylammonium bromide (CTAB) adsorption specific surface area of 140 m 2/g or more and 180 m 2/g or less
Data Source
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AI summary
The present invention provides a rubber composition containing: (A) a rubber component containing 10% by mass or more of at least one kind of rubber selected from diene rubber synthesized by emulsion polymerization and natural rubber and 90% by mass or less of another kind of diene rubber; (B) silica having a n-hexadecyltrimethylammonium bromide (CTAB) adsorption specific surface area of 140 m2/g or more and less than 180 m2/g measured according to a method described in ASTM D3765-92; (C) at least one silane coupling agent selected from a polysulfide compound and a thioester compound; and (D) a vulcanization accelerator, the rubber composition after vulcanization having an average aggregated aggregate area (nm2) of the silica of 2, 300 or less, and thus provides a rubber composition that is improved in low-heat-generation property.