Rubber Composition Using Caprolactam Disulfide for Faster Curing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing rubber compositions for tire inner liners struggle to balance sufficient scorch time with improved curing time and breaking energy performance, often compromising on one aspect at the expense of others.

Innovation Solution

A rubber composition based on an elastomer matrix, a reinforcing filler, and a crosslinking system that includes a vulcanizing agent with N,N′-Caprolactam disulfide as a sulfur donor, without soluble or insoluble sulfur, to achieve optimal scorch time, curing time, and breaking energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If conventional vulcanizing agents (soluble or insoluble sulfur) are used, then curing time can be reduced, but scorch time becomes insufficient and breaking energy performance degrades

Engineering Contradiction:
Improvecuring timeVSAvoidscorch time and breaking energy performance
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the vulcanizing agent by using N,N′-Caprolactam disulfide instead of conventional soluble or insoluble sulfur. This parameter change enables simultaneous achievement of sufficient scorch time, reduced curing time, and maintained breaking energy performance, resolving the technical contradiction between curing speed and performance reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite vulcanizing system comprising N,N′-Caprolactam disulfide in combination with specific accelerators (2-mercaptobenzothiazole and/or N-cyclohexyl-2-benzothiazolesulfonamide) and activators (zinc oxide and stearic acid). This composite material approach optimizes both the kinetic aspects (scorch and curing time) and mechanical properties (breaking energy) that cannot be achieved with single-agent systems

Inventive Principle:
Principle #40Composite materials

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 rubber composition achieves sufficient scorch time, reduced curing time, and enhanced breaking energy performance, effectively addressing the limitations of previous compositions.

Implementation Method 1

the vulcanizing agent comprises more than 0.0 phr and less than 10 phr of a sulfur doner comprising N,N′-Caprolactam disulfide

Methodology Applied
Scientific EffectSulfur donation: Chemical Bonding

Implementation Method 2

a crosslinking system; wherein the crosslinking system comprises a vulcanizing agent

Methodology Applied
Scientific EffectVulcanization: Chemical Bonding

Data Source

PatentUS20250026924A1A rubber composition
Publication Date: 2025.01.23 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

A rubber composition, which allows a sufficient scorch time while maintaining or improving the curing time and the breaking energy performance, is based on at least an elastomer matrix, a reinforcing filler, and a crosslinking system. The crosslinking system comprises a vulcanizing agent. The vulcanizing agent comprises more than 0.0 phr and less than 10 phr of a sulfur donor comprising N,N′-Caprolactam disulfide, and the vulcanizing agent comprises neither a soluble sulfur nor an insoluble sulfur, or the vulcanizing agent further comprises less than 0.4 phr of sulfur selected from a soluble sulfur, an insoluble sulfur and a combination thereof.