Non-silane Polymeric Coupler for Silica Rubber Bonding
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Solution Overview
Problem
Conventional silica fillers in rubber reinforcement, such as carbon black, face challenges in achieving low rolling resistance, reduced abrasive wear, and improved wet-skid resistance, which are only realized when the silica surface is pretreated with silane agents, limiting their effectiveness in high-performance tires.
Innovation Solution
A non-silane polymeric coupler with a dendritic polymer core and reactive end-groups, such as thiol or sulfide, is used to bridge silica and diene-based rubber, providing an alternative to traditional silane coupling agents like Si-69 and Si-363, enhancing the dispersion and interaction of silica in rubber compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silane coupling agents are used to treat silica surface, then the mechanical properties and wet skid resistance are improved, but VOC emissions and processing hazards increase
Solution Approach 1:
The invention changes the chemical composition parameters of the coupling agent by replacing silane-based compounds with polymeric couplers containing specific functional groups (carboxylic acid, phenolic hydroxyl, or sulfonic acid groups). This parameter change maintains the coupling effectiveness for improving wet skid resistance while eliminating the VOC emissions associated with conventional silane agents.
Solution Approach 2:
The patent employs polymeric couplers that function as effective coupling agents without requiring the long-chain silane structures that decompose to release VOCs. These polymeric couplers provide the necessary coupling function through their functional groups attached to the polymer backbone, avoiding the harmful byproducts of silane decomposition.
2Strength
If conventional silane coupling agents are used, then silica-rubber bonding is enhanced, but the complexity of the coupling mechanism increases
Solution Approach 1:
The coupling mechanism is segmented into two distinct functional parts: the polymeric backbone providing structural framework and the specific functional groups (carboxylic acid, phenolic hydroxyl, or sulfonic acid) providing the coupling chemistry. This segmentation simplifies the overall mechanism by separating the structural support function from the chemical bonding function, making the coupling process more controllable and predictable.
Solution Approach 2:
The polymeric coupler acts as an intermediary substance with a dual-function structure: the polymeric backbone serves as the structural mediator while the functional groups serve as the chemical mediators that bond to both silica and rubber. This intermediary approach simplifies the coupling mechanism by providing a well-defined molecular structure with predictable interaction sites, avoiding the complex decomposition and recombination steps of silane agents.
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 non-silane polymeric coupler achieves comparable or superior performance to conventional sulfur-containing organosilicon coupling agents, improving the mechanical properties and wet skid resistance of vulcanizable rubber compositions, particularly in pneumatic tire treads, while reducing VOC emissions and processing hazards.
Implementation Method 1
Bifunctional silanes capable of producing covalent bonds between the silica and the rubber are usually necessary particularly for the tire industry. The at least one reactive end-group may be selected from the group consisting of thiol, thioester, thioether, sulfanyl, mercapto, sulfide, and disulfide.
Data Source
AI summary
The present disclosure relates to a non-silane polymeric coupler. The non-silane polymeric coupler may include a dendritic polymer core having at least one reactive end group. The at least one reactive end-group may be selected from the group consisting of thiol, thioester, thioether, sulfanyl, mercapto, sulfide, and disulfide.