Bicomponent Fiber Segmentation for Spinnability

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Solution Overview

Problem

Bicomponent fibers with core/sheath geometry lose spinnability when even small amounts of the core material are present in the sheath or vice versa, making it difficult to recycle excess nonwoven web materials effectively.

Innovation Solution

Forming bicomponent fibers with dispersed polymer regions, such as 'island in the sea' geometries, which allow for greater intermixing of polymer components, enabling the incorporation of mixed material waste into primary or secondary polymer regions, thereby improving spinnability and recycling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If core/sheath geometry is used in bicomponent fibers, then enhanced softness is provided, but spinnability is lost when even small amounts of core material are present in the sheath

Engineering Contradiction:
ImprovespinnabilityVSAvoidfiber breakage
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The fiber cross-section is divided into multiple discrete polymer regions (primary and secondary regions) rather than a continuous core/sheath structure. This segmentation allows each polymer to be distributed throughout the fiber matrix, preventing the phase separation issues that cause fiber breakage during spinning while maintaining the softness benefits of bicomponent construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a composite fiber structure where multiple polymer materials are integrated in a dispersed regional configuration. The primary polymer forms a continuous matrix with secondary polymer regions distributed throughout, creating a composite structure that combines the advantages of both polymers while avoiding the spinnability problems of traditional core/sheath geometries.

Inventive Principle:
Principle #40Composite materials

2Productivity

If excess nonwoven web material is recycled to form bicomponent fiber, then feedstock polymer supply is reduced, but fiber breakage increases due to loss of spinnability

Engineering Contradiction:
Improverecycling efficiencyVSAvoidfiber spinning stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

By segmenting the fiber into discrete polymer regions rather than using continuous core/sheath geometry, the recycled mixed nonwoven web can be effectively incorporated without causing phase separation. The segmented structure allows uniform distribution of recycled material throughout the fiber, maintaining spinnability and preventing the fiber breakage that would otherwise occur during recycling processes.

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If core material is present in sheath or vice versa in bicomponent fibers, then fiber structure is maintained, but spinnability is significantly lost

Engineering Contradiction:
Improvefiber structureVSAvoidspinnability
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The fiber structure is segmented into distinct primary and secondary polymer regions that are dispersed throughout the cross-section. This segmentation maintains structural integrity and compositional stability while preventing the phase separation issues that cause loss of spinnability in traditional core/sheath geometries where one polymer is continuously present within the other.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3956512B1Nonwoven webs, and processes for manufacturing such
Publication Date: 2023.07.05 DOW GLOBAL TECHNOLOGIES LLC
  • EP3956512B1 patent drawingFigure 1A~1F
  • EP3956512B1 patent drawingFigure 2A~2B
  • EP3956512B1 patent drawingFigure 3

AI summary

In accordance with one embodiment of the present disclosure, a nonwoven web may be manufactured by a process that includes forming a bicomponent fiber and forming the bicomponent fiber into the nonwoven web. The bicomponent fiber may comprise one or more primary polymer regions and two or more secondary polymer regions. The primary polymer regions may comprise polyethylene. The secondary polymer regions may comprise polypropylene, polyester, or polyamide. The primary polymer regions may comprise at least 2.5 wt.% of polypropylene, polyester, or polyamide, or the secondary polymer regions may comprise at least 2.5 wt.% of polyethylene, or both.