Conjugated Diene Rubber Composition Silica Processability
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Solution Overview
Problem
Conjugated diene rubber compositions incorporating silica face challenges with poor processability, heat buildup, and inadequate wet-grip and abrasion resistance, despite efforts to enhance silica affinity and mechanical properties.
Innovation Solution
A conjugated diene rubber composition is developed, comprising branched conjugated diene rubber with polyorganosiloxane bonding and a conjugated diene rubber reacted with specific functional groups, optimizing molecular weight and structure to improve silica interaction and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If silica is incorporated into conventional rubber composition, then heat build up is reduced, but processability deteriorates and abrasion resistance is insufficient
Solution Approach 1:
The patent uses silane coupling agents as intermediary substances between silica and rubber. Specifically, organosilane compounds with reactive groups (such as alkoxy or hydroxyl groups) are introduced to bridge the interface between silica particles and rubber matrix, improving interfacial adhesion without compromising the low heat build-up property of silica. This mediator enables silica to maintain its thermal advantages while achieving acceptable processability through improved dispersion and bonding.
Solution Approach 2:
The patent modifies the chemical parameters of the rubber by introducing functional groups (such as amino, carboxyl, or hydroxyl groups) through chemical reactions or additives. These parameter changes enhance the polarity and reactivity of the rubber matrix, improving its affinity for silica surfaces. By adjusting compositional parameters like silane content, curing agents, and processing conditions, the patent achieves a balance between processability and heat build-up reduction.
2Strength
If silane coupling agent is used to improve silica affinity, then abrasion resistance is enhanced, but cost increases and wet-grip property improvement is limited
Solution Approach 1:
The patent optimizes the concentration and type of silane coupling agents to achieve cost-effective abrasion resistance. By carefully controlling the silane content and selecting cost-efficient organosilane compounds, the patent achieves sufficient interfacial bonding without excessive material costs. Additionally, the patent explores alternative coupling mechanisms and rubber modifications that reduce dependence on expensive silane additives.
3Temperature
If rubber is modified to enhance silica affinity, then reduced heat build up is achieved, but processability deteriorates and balance between wet-grip and abrasion resistance is poor
Solution Approach 1:
The patent applies local quality modification by introducing functional groups at specific locations within the rubber structure or at the rubber-silica interface. Rather than uniformly modifying the entire rubber matrix, the patent uses targeted chemical modifications or surface treatments that enhance silica affinity locally where needed, while preserving the bulk rubber's processing characteristics. This localized approach maintains good processability while achieving low heat build-up through improved silica dispersion and bonding.
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 enhanced processability, reduced heat buildup, improved wet-grip property, and high abrasion resistance when silica is incorporated, addressing the limitations of previous silica-based rubber compositions.
Implementation Method 1
a conjugated diene rubber having a structure such that at least three conjugated diene polymer chains are bonded together through a polyorganosiloxane
Implementation Method 2
a conjugated diene rubber having a structure such that it has been allowed to react with a compound having in the molecule at least one functional group selected from the group consisting of a >C═O group, a >C═S group, an amino group, an imino group, an epoxy group, a pyridyl group, an alkoxyl group and a halogen
Data Source
AI summary
A conjugated diene rubber composition comprising (A) 5-95 wt. % of a conjugated diene rubber having a structure such that at least three conjugated diene polymer chains are bonded together through a specific polyorganosiloxane having groups containing alkylene glycol repeating units and (B) 95-5 wt. % of a conjugated diene rubber having reacted with a compound having in the molecule a functional group selected from >C═O, >C═S, amino, imino, epoxy, pyridyl, alkoxyl and halogeno. This rubber composition gives, when silica is incorporated therein, a vulcanizable rubber composition having good processability and giving a rubber vulcanizate exhibiting sufficiently reduced heat build up, and having good wet-grip property and good abrasion resistance.