Azosilane Coupling Agent for Tire Rubber

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Solution Overview

Problem

The processing of rubber compositions containing inorganic fillers like silica is more difficult than those filled with carbon black, requiring coupling agents to facilitate bonding and dispersion, and existing coupling agents, such as bifunctional sulfurized silanes, while effective, can be improved for enhanced performance, especially in rubber matrices based on isoprene elastomers used in tire treads.

Innovation Solution

A new azosilane compound, specifically designed as a coupling agent with the formula (EtO)(RO)2Si-CH2-CH2-CH2-NH-CO-N=N-CO-NH-CH2-CH2-CH2-Si(OEt)(OR)2, is introduced to improve the bonding between diene elastomers and inorganic fillers, offering enhanced coupling performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional carbon black is used as filler, then processing is easier and good reinforcement is achieved, but rolling resistance is high and fuel consumption increases

Engineering Contradiction:

Improverolling resistanceVSAvoidprocessing difficulty

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent changes the chemical parameters of the filler from carbon black to inorganic fillers (silica, alumina), which have different surface properties and reinforcement mechanisms. This parameter change reduces hysteresis loss and rolling resistance while maintaining reinforcement through proper surface treatment with coupling agents

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces coupling agents as intermediary substances that mediate between the inorganic filler surface and the rubber matrix. These coupling agents improve the interfacial adhesion and facilitate processing, compensating for the initially poorer processability of inorganic fillers

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of energy

If inorganic fillers like silica are used, then rolling resistance is reduced and grip is improved, but processing becomes more difficult

Engineering Contradiction:

Improverolling resistanceVSAvoidprocessing difficulty

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent employs coupling agents as intermediary substances that mediate between the inorganic filler surface and the rubber matrix. These coupling agents improve the interfacial adhesion and facilitate processing, compensating for the initially poorer processability of inorganic fillers

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the surface parameters of inorganic fillers through chemical treatment with coupling agents, transforming them from poor-processability materials to well-dispersible, easily processable components that maintain the low rolling resistance benefit

Inventive Principle:

Principle #35Parameter changes

3Strength

If bifunctional sulfurized silanes are used as coupling agents, then good reinforcement and scorch safety are achieved, but coupling performance in isoprene elastomers can be further improved

Engineering Contradiction:

ImprovereinforcementVSAvoidcoupling performance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the chemical structure parameters of the coupling agent from sulfurized silanes to azosilane compounds. This structural parameter change provides better chemical compatibility and bonding performance specifically with isoprene elastomers, enhancing the coupling effectiveness while maintaining reinforcement

Inventive Principle:

Principle #35Parameter changes

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 new azosilane compound significantly improves the coupling performance in diene elastomers, particularly isoprene elastomers, leading to better reinforcement and reduced hysteresis in tire compositions, as demonstrated by improved tensile and dynamic properties in tests.

Implementation Method 1

a coupling agent providing the bond between the inorganic filler and the diene elastomer

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 2

an azosilane compound chosen from the following compounds: (EtO)(RO)2Si-CH2-CH2-CH2-NH-CO-N=N-CO-NH-CH2-CH2-CH2-Si(OEt)(OR)2

Methodology Applied

Scientific EffectSilane coupling: Chemical Bonding

Implementation Method 3

facilitating the dispersion of this filler inorganic within the elastomeric matrix

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentEP3395877B1Rubber composition for tyre comprising an azosilane coupling agent

Publication Date: 2020.05.13 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

The invention relates to a tire rubber composition based on at least one diene elastomer, an inorganic filler as a reinforcing filler, a coupling agent ensuring the bond between the inorganic filler and the diene elastomer, characterized in that the coupling agent is an azosilane compound selected from the following compounds: (EtO)(RO)2Si-CH2-CH2-CH2-NH-CO-N=N-CO-NH-CH2-CH2-CH2-Si(OEt)(OR)2, (RO)(EtO)2Si-CH2-CH2-CH2-NH-CO-N=N-CO-NH-CH2-CH2-CH2-Si(OR)(OEt)2 with Et=ethyl and R=C13H27(OCH2CH2)5.