Core-Spun Yarn With Recycled Cotton for Ring Spinning

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Solution Overview

Problem

Recycled cotton fibers with short lengths are unsuitable for ring spinning due to low strength and breakage issues, and blending with virgin cotton or polyester filaments results in poor mechanical properties and appearance.

Innovation Solution

A core spun yarn comprising a polyester filament core and a staple fiber sheath made of a blend of recycled cotton and regenerated cellulosic fibers, with specific length and elongation properties to enhance mechanical properties and elasticity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If recycled cotton fibers are used for yarn production, then environmental sustainability is improved, but yarn strength and workability deteriorate due to short fiber length

Engineering Contradiction:

Improveenvironmental sustainabilityVSAvoidyarn strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention uses a composite fiber structure where recycled cotton fibers (average length 6-16mm) are combined with longer regenerated cellulosic fibers (average length 25-40mm) to form a blended staple fiber. This composite approach allows the short recycled fibers to be supplemented by longer fibers that bridge gaps and provide structural support, thereby maintaining yarn strength while preserving the high recycled content (50-100%). The blend ratio is optimized so that the longer regenerated fibers compensate for the length deficiency of recycled fibers without compromising mechanical properties.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If recycled cotton fibers with short length are used, then production cost is reduced, but yarn breakage increases during manufacturing

Engineering Contradiction:

Improverecycled fiber contentVSAvoidyarn workability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The longer regenerated cellulosic fibers act as intermediary elements between the short recycled cotton fibers. These intermediary fibers span across the gaps created by short fiber ends, providing continuous load paths and preventing stress concentration at fiber ends. This mediator effect reduces the likelihood of yarn breakage during ring spinning and fabric manufacturing processes, thereby improving overall yarn workability while maintaining high recycled fiber content.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If polyester filaments are added to improve mechanical properties, then yarn strength is improved, but appearance and dyeability deteriorate

Engineering Contradiction:

Improveyarn mechanical propertiesVSAvoidappearance and dyeability

Core Design Contradiction:

StrengthVSShape

Solution Approach 1:

Instead of changing the material composition to include polyester, the invention changes the physical parameters of the fiber blend - specifically the average length and length distribution of cellulosic fibers. By combining short recycled cotton fibers (6-16mm) with longer regenerated cellulosic fibers (25-40mm), the invention achieves improved mechanical properties through optimized fiber length parameters while maintaining 100% cellulosic composition, thereby preserving natural appearance and dyeability characteristics.

Inventive Principle:

Principle #35Parameter changes

4Manufacturing precision

If ring spinning is used for recycled cotton, then yarn quality is improved, but production feasibility deteriorates due to short fiber length

Engineering Contradiction:

Improveyarn qualityVSAvoidproduction feasibility

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention modifies the fiber length parameter distribution in the staple fiber blend to make ring spinning feasible. By ensuring the presence of longer regenerated cellulosic fibers (25-40mm average length) in the blend, the invention provides sufficient fiber length for reliable ring spinning operation while incorporating short recycled fibers (6-16mm). This parameter optimization enables the use of ring spinning technology, which produces higher quality yarn with better uniformity and fewer defects, while maintaining production feasibility.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4450689B1A core spun yarn comprising short cellulosic staple fibers and process for its production

Publication Date: 2025.10.29 SANKO TEKSTIL ISLETMELERI SANAYI VE TICARET AS

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AI summary

A method for producing a yarn comprising the steps of: selecting a filament core, comprising a plurality of polyester filaments, wherein the elongation at break of the polyester filaments of the filament core is in the range of 5% to 15%, more preferably between 10% and 12%, when tested with DIN ISO 2062; selecting a staple fiber sheath, wherein at least 95% of the sheath is made of first staple fibers and second staple fibers, said first staple fibers being recycled cotton fibers, said second staple fibers being regenerated cellulosic fibers; and combining said filament core and said staple fiber sheath via ring spinning.