Functionalized Diene Elastomer for Low Hysteresis and Cold Flow Control

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Solution Overview

Problem

The tire industry faces challenges in reducing hysteresis in rubber compositions while maintaining processability and preventing cold flow, which affects storage and transportation, and existing solutions often compromise on hysteresis or processability.

Innovation Solution

A functionalized diene elastomer composed of a block copolymer functionalized with a tin group at the chain end or middle, a star-branched copolymer with a tin-derived agent, and a non-tin-functional block copolymer in limited quantities, achieving a balance in hysteresis, processability, and cold flow resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If functional groups are attached at chain ends to interact with reinforcing filler, then hysteresis is reduced, but processability deteriorates

Engineering Contradiction:

ImprovehysteresisVSAvoidprocessability

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent changes the molecular weight parameters of the polyisoprene blocks to a specific range (2,500-20,000 g/mol) and controls the overall molecular weight (50,000-350,000 g/mol) to achieve a balance where functional groups provide sufficient filler interaction for reduced hysteresis while maintaining adequate processability

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If narrow molecular distribution is used, then hysteresis is reduced, but cold flow increases

Engineering Contradiction:

ImprovehysteresisVSAvoidcold flow

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the molecular weight parameters within specific ranges and controls polydispersity to be less than 1.3, achieving a balance where narrow distribution reduces hysteresis while the specific molecular weight parameters prevent excessive cold flow

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite block copolymer structure combining polyisoprene blocks with diene elastomer blocks, where the specific architecture and composition balance the competing effects of narrow molecular distribution on hysteresis and cold flow

Inventive Principle:

Principle #40Composite materials

3Object-affected harmful factors

If molecular weight is increased to reduce cold flow, then processability deteriorates

Engineering Contradiction:

Improvecold flowVSAvoidprocessability

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent establishes an optimal molecular weight range (50,000-350,000 g/mol) that is high enough to reduce cold flow but not so high as to severely compromise processability, representing a carefully balanced parameter optimization

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9109109B2Functional diene block elastomer with a low PI and improved cold flow, and rubber composition containing same

Publication Date: 2015.08.18 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

The invention relates to a functionalized diene elastomer composed a) of a specific block copolymer functionalized, at the chain end or in the middle of the chain, by a tin functional group, b) of a specific block copolymer star-branched by tin and c) of a content of less than 15% by weight, with respect to the total weight of the functionalized diene elastomer, of a specific non-tin-functional block copolymer.