Cross-linked Ethylene Polymer Fabric Moldability

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Solution Overview

Problem

Existing knit fabrics for garments often lack a balanced combination of desirable properties such as dimensional stability, heat-set properties, stretchability, chemical resistance, abrasion resistance, and moldability, and may be limited by production methods like pulley feeding systems rather than eyelet systems.

Innovation Solution

A knit fabric comprising elastic fibers made from a reaction product of ethylene polymer and a cross-linking agent, with a cross-linking percentage between 10 to 90 weight percent, characterized by specific ethylene/α-olefin interpolymer characteristics that enable moldability and improved processability, including characteristics like average block index, molecular weight distribution, melting point, density, and elastic recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If cross-linked ethylene polymer fibers with gel content ≥30 wt.% are used, then moldability is improved, but fabric processability and production efficiency deteriorate

Engineering Contradiction:
ImprovemoldabilityVSAvoidproduction efficiency
Core Design Contradiction:
ShapeVSProductivity

Solution Approach 1:

The patent changes the gel content parameter from the conventional ≥30 wt.% to a specific range of 10-20 wt.%, which maintains adequate moldability while significantly improving fabric processability and production efficiency. This parameter optimization resolves the contradiction by finding the optimal balance point where sufficient cross-linking provides moldability without excessive cross-linking that would hinder production.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of using high levels of cross-linking (≥30 wt.% gel content), the patent applies partial cross-linking at optimized levels (10-20 wt.% gel content), which is sufficient to achieve the desired moldability for lingerie applications without the harmful effects of excessive cross-linking on fabric processing and production throughput.

Inventive Principle:
Principle #16Partial or excessive action

2Shape

If high gel content cross-linked fibers are used, then moldability is improved, but fiber breakage and defects increase

Engineering Contradiction:
ImprovemoldabilityVSAvoidfiber strength
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent optimizes the gel content parameter to 10-20 wt.%, which provides sufficient cross-linking for moldability while avoiding the fiber embrittlement and increased breakage associated with higher gel contents (≥30 wt.%). This parameter optimization maintains fiber strength and reduces defects.

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If conventional ethylene/α-olefin interpolymer is used, then fabric stretchability is achieved, but dimensional stability and heat-set properties deteriorate

Engineering Contradiction:
ImprovestretchabilityVSAvoiddimensional stability
Core Design Contradiction:
Length of moving objectVSStability of the object's composition

Solution Approach 1:

The patent creates a composite fiber structure by cross-linking ethylene/α-olefin interpolymer with cross-linking agents, forming a composite material that combines the stretchability of the elastomeric polymer with the dimensional stability and heat-set properties provided by the cross-linked network structure.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the polymer structure by introducing cross-links at optimized gel content levels (10-20 wt.%), which changes the physical and chemical properties of the material to simultaneously achieve stretchability, dimensional stability, and heat-set capability.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If pulley feeding system is used for fabric production, then production is possible, but productivity and throughput are limited

Engineering Contradiction:
Improveproduction feasibilityVSAvoidthroughput
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent changes the fabric properties by optimizing cross-linking parameters (gel content 10-20 wt.%), which improves processability and enables the fabric to be produced on more efficient eyelet knitting machines instead of being limited to pulley feeding systems, thereby increasing throughput and productivity.

Inventive Principle:
Principle #35Parameter changes

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 fabric achieves a balanced combination of desirable properties, including moldability, improved processability, and enhanced performance in applications like bras and swimsuits, with increased throughput and reduced defects like fiber breakage.

Implementation Method 1

the elastic fibers comprise the reaction product of at least one ethylene polymer and at least one cross-linking agent, said cross-linking agent being any means which cross-links one or more of the fibers

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Implementation Method 2

the fabric is capable of being molded, i.e., become set into a shape conforming to a three-dimensional mold when subjected to heat without substantial distension of the structure of the fabric

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2087155B1Fabric comprising elastic fibres of cross-linked ethylene polymer
Publication Date: 2017.04.26 DOW GLOBAL TECHNOLOGIES LLC
  • EP2087155B1 patent drawingFigure 1
  • EP2087155B1 patent drawingFigure 2
  • EP2087155B1 patent drawingFigure 3

AI summary

Knit fabric compositions have now been discovered that often have a balanced combination of desirable properties. Said fabric compositions comprise fibers of olefin block interpolymers or homogeneous branched ethylene polymers or a combination thereof. The fibers are characterized by an amount of crosslinking such that the fabric is capable of being molded.