Rubber Composition Using HDPA for Low Viscosity and Cured Cohesion

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Solution Overview

Problem

Existing rubber compositions face a challenge in reducing uncured viscosity for easier processing while maintaining or improving cured rubber's rigidity and cohesiveness, as adding plasticizers often compromises cured properties.

Innovation Solution

Incorporating 3-hydroxydiphenylamine (3-HDPA) or 4-hydroxydiphenylamine into rubber compositions without using methylene donors, which reduces uncured viscosity and enhances cured cohesiveness without affecting rigidity, by using a cross-linkable elastomer composition with a highly unsaturated diene elastomer and reinforcing fillers like carbon black or silica.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If plasticizers such as petroleum derived oils and low molecular weight resins are added to minimize uncured viscosity, then uncured viscosity is reduced for easier processing, but cured rigidity and cohesive properties are degraded

Engineering Contradiction:
Improveuncured viscosityVSAvoidcured cohesiveness
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent changes the chemical parameter of the rubber composition by incorporating 3-HDPA or 4-HDPA, which have specific molecular structures that interact with the rubber polymer chains. These compounds modify the viscosity characteristics without the harmful side effects of traditional plasticizers, achieving lower uncured viscosity while preserving cured cohesiveness through their unique chemical properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive or harmful plasticizers with 3-HDPA or 4-HDPA that serve their function temporarily during processing (reducing viscosity) and then become part of the cured network structure, contributing to both processing ease and final product strength without needing to be removed or replaced

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Ease of operation

If plasticizers are added to reduce uncured viscosity, then processing is easier, but cured rigidity is compromised

Engineering Contradiction:
Improveuncured viscosityVSAvoidcured rigidity
Core Design Contradiction:
Ease of operationVSStress or pressure

Solution Approach 1:

The patent modifies the chemical composition parameters by introducing 3-HDPA or 4-HDPA, which alter the rheological properties of the uncured rubber to reduce viscosity. Simultaneously, these compounds participate in the curing reaction to form a rigid cross-linked network, thus improving cured rigidity rather than compromising it

Inventive Principle:
Principle #35Parameter changes

3Strength

If methylene donors such as hexamethylenetetramine or hexamethoxymethylmelamine are used with HDPA to harden, then rubber physical properties are improved, but processability and cured cohesiveness are compromised

Engineering Contradiction:
Improvecured physical propertiesVSAvoidprocessability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent removes the methylene donor component from the traditional HDPA vulcanization system. By eliminating hexamethylenetetramine or hexamethoxymethylmelamine, the patent avoids the associated processing difficulties and cohesiveness issues while maintaining the beneficial effects of HDPA through alternative curing mechanisms

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses 3-HDPA or 4-HDPA as an intermediary substance that can facilitate cross-linking without requiring a methylene donor. These compounds act as both the cross-linking agent and the hardening agent, eliminating the need for separate methylene donor chemicals and improving overall processability

Inventive Principle:
Principle #24Intermediary (Mediator)

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 addition of HDPA significantly decreases uncured viscosity and increases elongational and tearing cohesiveness of the rubber, while maintaining or improving the cured rigidity, as demonstrated by reduced Mooney viscosity and increased break and tear strains without compromising MA10 modulus.

Implementation Method 1

Particular the invention uses 3-hydroxydiphenylamime or 4-hydroxydiphenylamine or their combinations in a rubber composition yielding a rubber composition having a low uncured viscosity for rubber processing

Methodology Applied
Scientific EffectMolecular interaction:

Implementation Method 2

Incorporating 3-hydroxydiphenylamine (3-HDPA) or 4-hydroxydiphenylamine into rubber compositions without using methylene donors, which reduces uncured viscosity and enhances cured cohesiveness

Methodology Applied
Scientific EffectCross-linking:

Implementation Method 3

a cross-linkable elastomer composition comprising, per 100 parts by weight of rubber (phr), a highly unsaturated diene elastomer

Methodology Applied
Scientific EffectVulcanization:

Implementation Method 4

a highly unsaturated diene elastomer, a reinforcing filler, and a property modifier

Methodology Applied
Scientific EffectReinforcement:

Data Source

PatentUS20240059869A1Method for forming rubber composition
Publication Date: 2024.02.22 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

A rubber composition is disclosed and more particularly, a rubber composition having low uncured viscosity for better green rubber handling and high cured cohesiveness desired cured article properties, methods for making them and articles made from such rubber compositions. Particularly the invention uses 3-hydroxydiphenylamime or 4-hydroxydiphenylamine or their combinations in a rubber composition yielding a rubber composition having a low uncured viscosity for rubber processing and a high cured cohesion and rigidity for the cured rubber product. Such a composition is particularly suitable for rubber applications including tires.