Functionalized Diene Elastomer Cold Creep Resistance
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Solution Overview
Problem
Existing rubber compositions for tires face challenges in reducing hysteresis while maintaining processing properties, leading to issues like cold creep, which affects storage and transport, and compromises the use of elastomers in tire applications.
Innovation Solution
A functionalized diene elastomer with 75-95% of the chain end functionalized with a silanol function or polysiloxane block and 5-25% star-shaped or coupled with tin is used, which improves cold creep resistance and maintains hysteretic and processing properties suitable for tire applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If diene polymers are functionalized with alkoxysilane derivatives to reduce hysteresis, then hysteresis properties improve, but the mixture becomes too stiff for practical tire applications
Solution Approach 1:
The patent changes the chemical parameter of the silane functionalization by using specifically non-hydrolysable alkoxyl groups (such as tert-butoxyl) instead of hydrolysable ones. This parameter change maintains the hysteresis-reducing effect while avoiding the stiffening problem that would make processing difficult.
2Ease of operation
If the Mooney of the elastomer is reduced to improve processing properties, then ease of operation improves, but cold creep resistance deteriorates
Solution Approach 1:
The patent uses a coupling agent that copies or mimics the functional groups already present on the silica surface (such as silanes with hydroxyl groups). This allows the elastomer to interact with the filler in a way that maintains both processing properties and cold creep resistance without needing to reduce Mooney.
3Loss of energy
If diene elastomers are functionalized to improve interaction with filler, then hysteresis properties improve, but structural modifications during solvent elimination cause degradation
Solution Approach 1:
The patent performs the functionalization with non-hydrolysable alkoxysilane groups before the solvent elimination step. This preliminary action ensures that the elastomer chains are already stabilized with their final functional groups in place, preventing any detrimental structural modifications during subsequent processing steps.
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 solution significantly reduces cold creep, enhancing storage and transport resistance while maintaining dynamic and processing properties, making the rubber composition suitable for tire manufacturing with improved rolling resistance.
Implementation Method 1
functionalized with an alkoxysilane having at least one remains non-hydrolysable alkoxyl when mixed with silica
Implementation Method 2
a living diene elastomer with a polymerization degree of 500 to 1,500,000 is subjected to the action of a coupling or star agent based on tin
Data Source
AI summary
The present invention relates to a specific functionalized diene elastomer. Said functionalized elastomer has a reduced cold flow without weakening the properties of a reinforced rubber composition containing same, in particular the implementation properties and hysteretic properties. Said functionalized diene elastomer has, at a chain end, a silanol function or a polysiloxane block having a silanol end and is partially coupled or studded with tin.