Polyester Elastomer Belt Resin Composition for Strength and Flex Fatigue

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Solution Overview

Problem

Existing resin belt materials face a trade-off between resin strength and flex fatigue resistance, with increased resin strength often leading to deteriorated flex fatigue resistance, particularly at low temperatures, and vice versa, which is problematic for applications requiring performance across a wide temperature range.

Innovation Solution

A thermoplastic polyester elastomer resin composition comprising 80-92.99% thermoplastic polyester elastomer, 7-19.99% glass fiber, and 0.01-5% crystal nucleator, with a specific polyester block copolymer structure and processing conditions to achieve balanced resin strength and flex fatigue resistance at both room and low temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If glass fiber is added to increase resin strength, then resin strength is improved, but flex fatigue resistance is deteriorated particularly at low temperature

Engineering Contradiction:
Improveresin strengthVSAvoidflex fatigue resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters by incorporating specific polyether segments (polyethylene oxide, polypropylene oxide, or copolymers) in controlled amounts (5-60 mass%) within the polyester elastomer structure. This compositional parameter adjustment enables the material to achieve both high resin strength and maintained flex fatigue resistance at low temperatures, resolving the trade-off between strength and flexibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite polyester block copolymer structure combining hard segments (crystalline aromatic polyester) for strength with soft segments (aliphatic polyether) for flexibility and low-temperature performance. This composite structure at the molecular level allows simultaneous achievement of high resin strength and excellent flex fatigue resistance even when glass fiber is added

Inventive Principle:
Principle #40Composite materials

2Strength

If resin strength is increased, then belt strength is improved, but flex fatigue resistance is deteriorated

Engineering Contradiction:
Improvebelt strengthVSAvoidflex fatigue resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention adjusts the molecular weight and composition parameters of the polyester elastomer, specifically controlling the ratio of hard to soft segments and the molecular weight of the polyether segments. These parameter changes enable the resin to maintain high strength while preserving flex fatigue resistance, allowing both belt strength and reliability to be improved simultaneously

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If flexibility is increased, then low temperature performance is improved, but resin strength is deteriorated

Engineering Contradiction:
ImproveflexibilityVSAvoidresin strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The invention applies local quality by creating distinct hard and soft segments within the polyester block copolymer structure. The hard segments (crystalline aromatic polyester) provide localized strength and structural integrity, while the soft segments (aliphatic polyether) provide localized flexibility and low-temperature performance. This segmentation allows both flexibility and resin strength to be improved without compromising either property

Inventive Principle:
Principle #3Local quality

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 composition achieves high resin strength and excellent flex fatigue resistance at room temperature, while maintaining flexibility and impact resistance even at low temperatures, ensuring reliable performance in a wide temperature range.

Implementation Method 1

0.01 to 5.0% by weight of a crystal nucleator (C)

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 2

a polyester block copolymer including 40 to 70% by weight of a high melting point crystalline polymer segment (a1) including a crystalline aromatic polyester unit, and 30 to 60% by weight of a low melting point polymer segment (a2) including an aliphatic polyether unit

Methodology Applied
Scientific EffectPhase transition: Phase Change

Data Source

PatentUS11781008B2Thermoplastic polyester elastomer resin composition for resin belt materials, and molded resin belt
Publication Date: 2023.10.10 TORAY CELANESE CO LTD

AI summary

A polyester elastomer resin composition for resin belt materials contains 80-92.99% by weight of a thermoplastic polyester elastomer (A), 7-19.99% by weight of glass fibers (B) and 0.01-5.0% by weight of a crystal nucleator (C), and which is also characterized in that: the thermoplastic polyester elastomer (A) is a polyester block copolymer which contains 40-70% by weight of a high melting point crystalline polymer segment (a1) that is composed of a crystalline aromatic polyester unit and 30-60% by weight of a low melting point polymer segment (a2) that is composed of an aliphatic polyether unit; and the melt flow rate as determined in accordance with ASTM D1238 at 230° C. under a load of 2,160 g is 1.0 g/10 min or more but less than 10.0 g/10 min.