Conjugated Diene Rubber Coupling for Tire Abrasion and Heat
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Solution Overview
Problem
Current rubber compositions for tires lack sufficient mechanical strength, abrasion resistance, and reduced heat build-up, with existing methods failing to produce a conjugated diene rubber that effectively balances these properties.
Innovation Solution
A method involving the use of a specific coupling agent, such as silicon halides or alkoxysilanes, to react with a polymer having an active terminal obtained through polymerization of a monomer mixture containing conjugated diene and aromatic vinyl monomers, resulting in a conjugated diene rubber with a weight-average molecular weight of 10,000 to 3,000,000, enhancing mechanical strength, abrasion resistance, and reduced heat build-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If silica is added in place of carbon black to improve reduced heat build-up, then heat generation is reduced, but abrasion resistance deteriorates
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance between silica and rubber. The coupling agent contains both silane groups that bond with silica and organic functional groups that interact with rubber, creating a bridge that enhances the affinity between silica and rubber while maintaining the low heat build-up properties of silica
Solution Approach 2:
The invention creates a composite rubber composition containing rubber, silica, and silane coupling agent. This composite structure allows silica to provide low heat build-up while the silane coupling agent ensures strong interfacial bonding, thereby achieving both reduced heat generation and improved abrasion resistance simultaneously
2Strength
If a coupling agent is used to improve silica-rubber affinity, then abrasion resistance is improved, but reduced heat build-up may deteriorate
Solution Approach 1:
The invention optimizes the molecular weight parameters of the coupling agent (number-average molecular weight between 300-100,000) and the ratio of functional groups per polymer molecule (at least 5) to achieve the optimal balance between abrasion resistance and heat build-up reduction. By controlling these parameters, the coupling agent provides sufficient reinforcement without excessive heat generation
3Strength
If the coupling reaction is made more intensive to improve abrasion resistance, then mechanical strength is improved, but production stability deteriorates
Solution Approach 1:
The invention specifies precise parameter ranges for the coupling reaction: number-average molecular weight of 300-100,000 and at least 5 functional groups per polymer molecule. These controlled parameters ensure consistent and stable coupling reactions that produce reliable mechanical strength without causing production instability
Solution Approach 2:
The invention establishes clear quantitative criteria (molecular weight range and functional group ratio) that serve as feedback controls for the coupling reaction process. By monitoring and controlling these parameters, the production process achieves both high mechanical strength and stable, repeatable results
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 method stabilizes the production of conjugated diene rubber with desired molecular weights, leading to tires that exhibit improved mechanical strength, abrasion resistance, and reduced heat build-up, outperforming previous compositions.
Implementation Method 1
causing the polymer having an active terminal to react with a polyfunctional coupling agent such as tin tetrachloride to give a branched polymer
Data Source
AI summary
[PROBLEMS] To provide a conjugated diene polymer capable of giving a vulcanized rubber excellent in abrasion resistance, reduced heat build-up and the like, its manufacturing method, a rubber composition for tires containing the conjugated diene rubber, and a tire. [MEANS FOR SOLVING PROBLEMS] The manufacturing method comprises adding a compound represented by the following general formula (I) as a coupling agent to a solution that contains a polymer having an active terminal obtained through polymerization of a monomer mixture comprising a conjugated diene monomer or the like in an inert solvent using an organic active metal as an initiator, and causing the compound to react with the polymer having the active terminal. [Formula 1] SiX1pR13-p-(A1-A3-A2)n-SiX2qR23-q (I) {In the formula, X1 and X2 each represent a halogen atom or an alkoxy group having from 1 to 20 carbon atoms. In the compound of the formula, the total of the number of the halogen atoms and the number of the alkoxy groups having from 1 to 20 carbon atoms is at least 5. R1 and R2 each represent a monovalent hydrocarbon group having from 1 to 20 carbon atoms. A1 and A2 each represent a single bond or a divalent hydrocarbon having from 1 to 20 carbon atoms. A3 represent a group represented by the formula: -(SiX3rR32-r)m-, or the like.}