Thermoplastic Elastomer Composition for Oil-Impermeable Auto Hoses

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Solution Overview

Problem

Olefin thermoplastic elastomers used in automobile parts have low oil resistance, making them unsuitable for applications where they come into contact with engine oil, lubricating oil, or grease.

Innovation Solution

A thermoplastic elastomer composition comprising an ethylene copolymer with a weight-average molecular weight of 350,000 or more, a crystalline olefin polymer, a crosslinking agent, and a plasticizer, where the plasticizer content is less than 130 parts by mass based on 100 parts by mass of the copolymer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If olefin thermoplastic elastomers are used in automobile parts, then the parts are lightweight and easy to recycle, but the parts have low oil resistance and cannot be used in applications contacting engine oil or lubricating oil

Engineering Contradiction:
Improveoil resistanceVSAvoidapplication range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention changes the chemical composition parameters of the thermoplastic elastomer by incorporating specific additives and modifying the polymer structure. The composition includes ethylene/α-olefin copolymer (50-90 parts), crystalline olefin polymer (10-50 parts), and specific additives, creating a material that maintains the original lightweight and recyclable properties while achieving oil resistance suitable for automobile parts contacting engine oil and lubricating oil.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite thermoplastic elastomer material by combining multiple polymer components and additives. The composite structure integrates ethylene/α-olefin copolymer with crystalline olefin polymer and functional additives, producing a material that exhibits both the processing advantages of thermoplastics and the oil resistance properties needed for demanding automobile applications.

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional thermoplastic elastomer composition is used, then the composition is easy to process, but the molded body has poor oil permeability resistance

Engineering Contradiction:
Improveoil permeability resistanceVSAvoidprocessing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention modifies the compositional parameters by specifying precise ratios of ethylene/α-olefin copolymer (50-90 parts per 100 parts total polymer) and crystalline olefin polymer (10-50 parts per 100 parts total polymer), along with controlled amounts of additives. This parameter optimization maintains good processability while achieving the required oil permeability resistance for automobile parts.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20250145813A1Thermoplastic elastomer composition and application thereof
Publication Date: 2025.05.08 MITSUI CHEMICALS INC

AI summary

An object of the present disclosure is to provide a thermoplastic elastomer composition with good oil permeability resistance (oil impermeability). The present disclosure pertains to a thermoplastic elastomer composition containing an ethylene copolymer (A) having a weight-average molecular weight of 350,000 or more, a crystalline olefin polymer (B), a crosslinking agent (C), and a plasticizer (D), wherein the content of the plasticizer (D) is less than 130 parts by mass based on 100 parts by mass of the copolymer (A).