Modified Conjugated Diene Rubber Silane Coupling
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Solution Overview
Problem
Conventional methods for modifying conjugated diene rubber are complex and difficult to practice, necessitating a novel technique to improve the bonding between conjugated diene rubber and reinforcing agents like silica and carbon black for enhanced mechanical properties and reduced rolling resistance.
Innovation Solution
A two-step modification process involving an alkali metal ion-containing conjugated diene rubber reacted with a first alkoxysilane modifier and then a second oxygen- or nitrogen-containing modifier, followed by hydrolysis and reaction with water, to introduce alkoxysilane groups and improve bonding with silica.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional two-stage modification processes are used with multiple coupling agents, then bonding between rubber and reinforcing agents is improved, but process complexity increases significantly
Solution Approach 1:
The patent combines multiple modification functions into a single silane coupling agent that contains both the coupling function (triethoxysilylethyl group) and the reinforcing agent interaction function (polymerizable double bond). This single agent performs both the bonding to rubber and the bonding to silica/carbon black, eliminating the need for sequential two-stage modification processes and reducing overall process complexity while maintaining bonding strength.
Solution Approach 2:
The silane coupling agent used in this invention serves multiple functions simultaneously: it acts as a coupling agent to bond rubber chains to reinforcing agents, provides polymerizable double bonds for incorporation into the rubber matrix, and creates silane crosslinks after hydrolysis. This multi-functionality replaces the need for separate coupling agents and modifiers used in conventional two-stage processes.
2Strength
If multiple modifiers are applied in sequence, then bonding performance is enhanced, but manufacturing time and cost increase
Solution Approach 1:
The silane coupling agent is designed with pre-installed functional groups (triethoxysilylethyl and polymerizable double bonds) that enable it to perform multiple functions in a single application step. The ethoxysilane groups are pre-positioned to hydrolyze and crosslink, while the double bonds are pre-positioned to polymerize with the rubber matrix, eliminating the need for sequential addition of multiple modifiers and reducing manufacturing time.
3Reliability
If silica and carbon black are added as reinforcing agents, then rolling resistance and wet-skid resistance are improved, but bond strength between rubber and fillers is insufficient without modification
Solution Approach 1:
The silane coupling agent acts as an intermediary between the rubber matrix and the inorganic reinforcing agents (silica and carbon black). The triethoxysilylethyl groups hydrolyze to form silane crosslinks that bond to the rubber chains, while the polymerizable double bonds incorporate the coupling agent into the rubber matrix. This creates a bridging structure that strongly bonds the organic rubber to the inorganic fillers, enabling improved wet-skid resistance and steering stability.
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 modified conjugated diene rubber exhibits improved mechanical properties, reduced rolling resistance, and enhanced wet-skid resistance, resulting in better steering stability and reliability for tire applications.
Implementation Method 1
followed by hydrolysis and reaction with water, to introduce alkoxysilane groups
Data Source
AI summary
A method of forming modified conjugated diene rubber includes (a) reacting an alkali metal ion-containing conjugated diene rubber with a first modifier having a structural formula (I),wherein R1, R2, R3 are each independently selected from the group consisting of C1-C12 of alkyl and C2-C12 of alkenyl groups and C6-C12 of aromatic group, and R4 is selected from the group consisting of C1-C12 of alkyl, C2-C12 of alkenyl, C1-C12 of alkoxy groups and C6-C12 of aromatic group; and (b) adding a second modifier having a structural formula (II) after (a),HO—R5—Y (II)wherein R5 is selected from the group consisting of C1-C12 of alkylene, C2-C12 of alkenylene, C3-C12 of alicyclic groups and C6-C12 of aromatic group, and Y is selected from the group consisting of oxygen-containing C1-C12 group and nitrogen-containing, C1-C12 group, wherein Y has the oxygen atom or the nitrogen atom directly connected to a carbon atom of R5.