Rubber Composition Epoxy Resin Amine Hardener Processability

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Solution Overview

Problem

Conventional rubber compositions for tires that use phenolic resin with hexamethylenetetramine (HMT) or hexamethoxymethylmelamine (H3M) as hardeners produce formaldehyde during vulcanization, posing environmental concerns, and have limitations in processability and production costs, while seeking to maintain stiffness and rolling resistance.

Innovation Solution

A rubber composition incorporating an epoxy resin with a specific amine-comprising hardener, featuring primary amine functional groups on a six-membered aromatic ring, which improves processability by enhancing scorch time and viscosity before curing, offering a superior processability/stiffness compromise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If phenolic resin with HMT or H3M hardener is used, then stiffness is improved, but formaldehyde is produced during vulcanization

Engineering Contradiction:

ImprovestiffnessVSAvoidformaldehyde production

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the hardener system by replacing HMT/H3M with alternative hardeners that do not produce formaldehyde, while maintaining the stiffness-enhancing functionality through the epoxy resin-hardener reaction system

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful formaldehyde-producing reaction into a beneficial alternative crosslinking mechanism using epoxy resin and compatible hardeners, which achieve similar or superior reinforcement without the harmful byproduct

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Strength

If conventional phenolic resin hardener system is used, then stiffness is achieved, but processability in raw state deteriorates

Engineering Contradiction:

ImprovestiffnessVSAvoidprocessability

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent optimizes the molecular weight, functional group density, and chemical structure parameters of the epoxy resin and hardener combination to achieve an optimal balance between raw state processability (viscosity, scorch time) and cured state stiffness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite crosslinking system combining epoxy resin with specific hardeners that provide both adequate processing time and final stiffness, leveraging the synergistic effects of the resin-hardener interaction

Inventive Principle:

Principle #40Composite materials

3Object-generated harmful factors

If epoxy resin with conventional hardener is used, then formaldehyde production is eliminated, but processability deteriorates

Engineering Contradiction:

Improveformaldehyde eliminationVSAvoidprocessability

Core Design Contradiction:

Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent adjusts critical parameters including epoxy resin molecular weight (200-1000 g/mol), hardener molecular weight (100-500 g/mol), and their molar ratio to optimize both processability and formaldehyde-free crosslinking performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses specific ratios of epoxy resin to hardener (0.8-1.2 molar ratio) to ensure adequate processing time while achieving complete crosslinking and stiffness development, avoiding both insufficient and excessive hardening

Inventive Principle:

Principle #16Partial or excessive action

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 composition achieves improved processability and stiffness, reducing production costs and environmental impact by eliminating formaldehyde formation, with enhanced scorch time and Mooney plasticity, suitable for internal layers and treads in tires.

Implementation Method 1

Crosslinking of the resin is then brought about, during the curing of the rubber matrix, by formation of methylene bridges between the carbons in the ortho and para positions of the phenolic nuclei of the resin and the methylene donor

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

the combination of a phenolic resin, methylene acceptor, with HMT or H3M, methylene donor, produces formaldehyde during the vulcanization of the rubber composition

Methodology Applied

Scientific EffectVulcanization:

Data Source

PatentUS11499036B2Rubber composition comprising an epoxide resin and a specific amine hardener

Publication Date: 2022.11.15 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

A rubber composition exhibiting an improved processability/stiffness compromise is based on at least a diene elastomer, a reinforcing filler, a crosslinking system, between 1 and 30 parts by weight per hundred parts by weight of elastomer, phr, of an epoxy resin and between 1 and 15 phr of a specific amine-comprising hardener comprising in particular at least two primary amine functional groups located on at least one six-membered aromatic ring and at least two Ri radicals, which are identical or different, selected from the group consisting of linear or branched C1-C6 alkyl radicals, halogens, and ethers, tertiary amines, thioethers, ketones, esters and amides, substituted by linear or branched C1-C6 alkyl radicals, the said ring not comprising a hydrogen atom located in the ortho position with respect to the primary amine functional groups.