Cyclohexyl p-Phenylenediamine Antidegradant for Faster Rubber Vulcanization

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Solution Overview

Problem

Current p-phenylenediamine antidegradants, such as 6PPD, do not adequately improve vulcanization speed, scorching time, and thermal oxidative aging resistance of rubber materials while maintaining original physical properties like flexing resistance and dynamic fatigue resistance.

Innovation Solution

The development of N-(3,5,5-trimethylcyclohexyl)-N′-phenyl p-phenylenediamine, synthesized through a condensation hydrogenation reaction using a catalyst like Pd/C, Pt/C, or Pt—S/C in a fixed bed reactor, which increases vulcanization speed, shortens scorching time, and enhances thermal oxidative aging resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional p-phenylenediamine antidegradant (6PPD) is used, then original physical properties and flexing resistance are maintained, but vulcanization speed is insufficient and scorching time is long

Engineering Contradiction:

Improvevulcanization speedVSAvoidscorching time

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The invention modifies the chemical structure of conventional p-phenylenediamine antidegradants by introducing a cyclohexyl group with specific methyl substitutions at positions 3 and 5. This structural parameter change enhances the antidegradant's ability to promote vulcanization reactions, thereby increasing vulcanization speed and reducing scorching time while maintaining protective functions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite molecular structure combining phenylenediamine with cyclohexyl groups, forming a new antidegradant molecule that integrates both the protective properties of p-phenylenediamine and the vulcanization-promoting properties of cyclohexyl structures, achieving multiple functions in a single compound.

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional p-phenylenediamine antidegradant (6PPD) is used, then good original physical properties are maintained, but thermal oxidative aging resistance is insufficient

Engineering Contradiction:

Improvethermal oxidative aging resistanceVSAvoidoriginal physical properties

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention introduces specific methyl substitutions at the 3 and 5 positions of the cyclohexyl group, which modifies the steric and electronic parameters of the antidegradant molecule. These parameter changes enhance thermal oxidative aging resistance by improving the molecule's stability under thermal stress while preserving its compatibility with rubber matrices and original physical properties.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If new cyclohexyl-containing antidegradant is used, then vulcanization speed increases and scorching time shortens, but manufacturing complexity increases

Engineering Contradiction:

Improvevulcanization speedVSAvoidsynthesis process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The invention employs preliminary protection of the amino groups in p-phenylenediamine before cyclohexylation, and subsequent deprotection to reveal the active amino groups. This preliminary action sequence ensures that the cyclohexyl group is introduced at the correct position without affecting the essential amino groups, simplifying the overall synthesis by preventing side reactions and eliminating the need for complex purification steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention uses a protecting group as an intermediary during the synthesis process. This intermediary temporarily masks the amino groups, allowing cyclohexylation to occur selectively on other parts of the molecule, and is then removed to reveal the final product. This intermediary approach simplifies the synthesis by enabling selective reactions that would otherwise be difficult to control.

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

This new antidegradant improves vulcanization speed, reduces scorching time, and enhances thermal oxidative aging resistance while maintaining good original physical properties, flexing resistance, and dynamic fatigue resistance, with improved solubility, compatibility, and ozone resistance compared to existing antidegradants.

Implementation Method 1

reacting a compound A, 4-aminodiphenylamine, and hydrogen in a condensation hydrogenation reaction in presence of a catalyst

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

reacting a compound A, 4-aminodiphenylamine, and hydrogen in a condensation hydrogenation reaction

Methodology Applied

Scientific EffectHydrogenation: Hydrogenation

Data Source

PatentUS20240360070A1N-(3,5,5-trimethylcyclohexyl)-n'-phenyl p-phenylenediamine and synthesis method therefor

Publication Date: 2024.10.31 SENNICS CO LTD

AI summary

A p-phenylenediamine rubber antidegradant compound has a cycloalkyl structure named N-(3,5,5-trimethylcyclohexyl)-N′-phenyl p-phenylenediamine. The compound is prepared by reacting a compound A, 4-aminodiphenylamine, and hydrogen in a condensation hydrogenation reaction in presence of a catalyst, and the compound A is 3,5,5-trimethyl-2-cyclohexen-1-one, 3,3,5-trimethylcyclohexanone, 3,3,5-trimethylcyclohexanol, or combination thereof.