Rubber Composition Ozone Resistance via Petroleum Wax Proportions

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Solution Overview

Problem

Existing rubber compositions face a trade-off between ozone crack resistance and discoloration resistance, with PTL 1 focusing primarily on static ozone resistance at high temperatures and neglecting dynamic ozone resistance and appearance issues.

Innovation Solution

A rubber composition comprising a rubber component, a petroleum wax with a C20-C34 hydrocarbon component and a C35 or higher hydrocarbon component in specific mass proportions, along with an antidegradant, to balance static ozone resistance, dynamic ozone resistance, and discoloration resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If increased amounts of antidegradants are compounded into rubber compositions to improve ozone crack resistance, then ozone resistance is improved, but discoloration resistance deteriorates due to color changes into brown during storage

Engineering Contradiction:
Improveozone crack resistanceVSAvoidappearance (color stability)
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The invention changes the molecular weight distribution parameters of the petroleum wax by specifying a particular proportion range (15-30% for C20-C34 hydrocarbon component and 70-85% for C35 or higher hydrocarbon component). This parameter optimization allows the wax to form an effective protective barrier against ozone while minimizing discoloration, thus resolving the contradiction between ozone resistance and appearance maintenance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite wax system combining two different hydrocarbon component ranges (C20-C34 and C35 or higher) in specific proportions. This composite approach creates a synergistic effect where the lighter components provide flexibility and the heavier components provide stability, achieving both ozone protection and color stability without requiring excessive antidegradant loading.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3530691B1Rubber composition and tire
Publication Date: 2021.12.01 BRIDGESTONE CORP

AI summary

Provided is a rubber composition in which static ozone resistance, dynamic ozone resistance and discoloration resistance are highly balanced. Also provided is a tire in which static ozone resistance, dynamic ozone resistance and discoloration resistance are highly balanced. The rubber composition comprises a rubber component, a petroleum wax, and an antidegradant, wherein the petroleum wax comprises a C20-C34 hydrocarbon component and a C35 or higher hydrocarbon component, and a proportion of the C20-C34 hydrocarbon component is 15% by mass to 30% by mass and a proportion of the C35 or higher hydrocarbon component is 70% by mass to 85% by mass, based on a total mass of the C20-C34 hydrocarbon component and the C35 or higher hydrocarbon component.