Brake Fluid-Resistant Rubber Composition With Higher Tear Strength

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Solution Overview

Problem

Ethylene-propylene rubbers used in brake fluid-resistant applications face challenges with low tear strength after peroxide vulcanization, leading to unqualified products and increased production costs, while ethylene/1-octene copolymers have difficulty in crosslinking due to steric hindrance, affecting processing efficiency and product performance.

Innovation Solution

A rubber composition incorporating branched polyethylene with a degree of branching of at least 50 branches/1000 carbon atoms, combined with EPM and EPDM, and peroxide vulcanization, to enhance aging resistance and crosslinking performance, thereby improving tear strength and compression set resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If peroxide vulcanization is used on ethylene-propylene rubber, then aging resistance is improved, but tear strength decreases

Engineering Contradiction:
Improveaging resistanceVSAvoidtear strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters of the rubber by incorporating branched polyethylene with specific branching degree (50-200 branches/1000 carbon atoms) and controlling the content of EPM and EPDM within specific ranges. This parameter optimization allows the rubber to achieve both good aging resistance through peroxide vulcanization and adequate tear strength by reducing tertiary carbon content to 5-30 mol%

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite rubber system combining branched polyethylene, EPM, and EPDM in specific proportions. This composite formulation leverages the complementary properties of each component: branched polyethylene provides structural framework with controlled branching, EPM contributes to aging resistance, and EPDM enhances crosslinking capability, achieving a balance between aging resistance and tear strength

Inventive Principle:
Principle #40Composite materials

2Reliability

If EPM is used to improve aging resistance, then aging resistance increases, but mechanical strength decreases

Engineering Contradiction:
Improveaging resistanceVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the content of EPM within 10-80 parts by weight and controls the propylene content and branching degree of the polyethylene components. By adjusting these parameters, the formulation achieves adequate aging resistance from EPM while compensating for its low mechanical strength through the reinforcing effect of branched polyethylene and crosslinking from EPDM

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent formulates a composite system where EPM is combined with branched polyethylene and EPDM. The branched polyethylene provides structural support and the EPDM contributes to crosslinking, compensating for EPM's low mechanical strength while maintaining its aging resistance benefits

Inventive Principle:
Principle #40Composite materials

3Reliability

If degree of branching is reduced to improve aging resistance, then aging resistance improves, but crosslinking ability decreases

Engineering Contradiction:
Improveaging resistanceVSAvoidcrosslinking ability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent precisely controls the degree of branching within 50-200 branches/1000 carbon atoms and tertiary carbon content at 5-30 mol%. This optimized parameter range maintains sufficient aging resistance while ensuring adequate crosslinking ability through the balanced composition of branched polyethylene, EPM, and EPDM

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system where the crosslinking ability is distributed across multiple components: branched polyethylene provides crosslinking sites through its branches, EPM contributes to the crosslinked network, and EPDM with its diene groups enhances crosslinking density. This composite approach ensures adequate crosslinking even with reduced branching degree

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 improved aging resistance, mechanical properties, and crosslinking performance, reducing the probability of tearing and enhancing processing efficiency, while minimizing the use of plasticizers and their extraction by brake fluid.

Implementation Method 1

peroxide vulcanization

Methodology Applied
Scientific EffectFree radical reaction:

Implementation Method 2

crosslinking performance

Methodology Applied
Scientific EffectCrosslinking:

Implementation Method 3

difficulty in crosslinking due to steric hindrance

Methodology Applied
Scientific EffectSteric hindrance:

Data Source

PatentUS12180355B2Rubber composition, processing method thereof, and braking-resistant liquid product using the same
Publication Date: 2024.12.31 HANGZHOU XINGLU TECHNOLOGIES CO LTD

AI summary

The present invention discloses a rubber composition, a processing method thereof, and also a brake fluid-resistant product using the rubber composition and a production method thereof. The rubber composition comprises, in parts by weight, 100 parts of a rubber matrix; 1.5-8 parts of a crosslinking agent 40-140 parts of a reinforcing filler; and 0-40 parts of a plasticizer, wherein the rubber matrix comprises, based on 100 parts by weight of the rubber matrix, a branched polyethylene with a content represented as A, in which 0<A≤100 parts; an EPM with a content represented as B, in which 0≤B<100 parts; and an EPDM with a content represented as C, in which 0≤C<100 parts. The rubber composition is useful in the production of brake fluid-resistant brake rubber hose and brake rubber diaphragm. The beneficial effect is that since the rubber composition comprises the branched polyethylene, the tear strength of the rubber compound is improved, thereby reducing the probability of tearing of the product during the production process and improving the overall processing performance.