Core-Spun Yarn with Recycled Cotton Sheath and Polyester Core

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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 results in poor mechanical properties and appearance.

Innovation Solution

A core spun yarn is developed using a blend of recycled cotton fibers and regenerated cellulosic fibers, with a polyester filament core and a sheath composed of a mixture of recycled cotton and viscose fibers, ensuring a high percentage of recycled content and improved mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If recycled cotton fibers are used in ring spinning, then environmental sustainability is improved, but yarn strength deteriorates due to short fiber length

Engineering Contradiction:

Improveenvironmental impactVSAvoidyarn strength

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent uses a composite structure with a polyester filament core and a cotton fiber sheath. The core provides tensile strength while the sheath provides the natural cotton appearance and feel. This composite approach allows the yarn to meet strength requirements while using 100% recycled cotton in the sheath portion.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention implements a core-spun yarn structure where the polyester filaments are nested within the cotton fiber sheath. The core acts as an internal support structure that reinforces the outer cotton layer, enabling short recycled fibers to form a strong yarn without compromising mechanical properties.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Loss of substance

If short recycled cotton fibers are used, then recycling rate is improved, but yarn workability deteriorates due to fiber breakage

Engineering Contradiction:

Improverecycling rateVSAvoidyarn workability

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

By creating a composite yarn with a continuous polyester core and recycled cotton sheath, the invention transforms the weakness of short fibers into a non-issue. The continuous core prevents breakage during processing while the short cotton fibers maintain high recycling content in the visible sheath portion.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The polyester core acts as an intermediary element that transfers and distributes mechanical stresses along the yarn length, protecting the short recycled cotton fibers from breakage during ring spinning and subsequent fabric manufacturing processes.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If polyester is added to improve mechanical properties, then yarn strength is improved, but appearance deteriorates with poor cotton look

Engineering Contradiction:

Improvemechanical propertiesVSAvoidappearance

Core Design Contradiction:

StrengthVSShape

Solution Approach 1:

The invention applies local quality by confining the polyester material to the internal core where it provides strength, while the external sheath consists entirely of natural cotton fibers that provide the desired cotton appearance and feel. This spatial separation of functions resolves the appearance-strength conflict.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The nested structure places the polyester core inside the cotton sheath, hiding the synthetic material from visual inspection. The yarn surface presents only natural cotton fibers, maintaining authentic cotton appearance while the hidden core provides the necessary mechanical reinforcement.

Inventive Principle:

Principle #7Nested doll (Nesting)

4Object-affected harmful factors

If recycled cotton fibers are used, then environmental sustainability is improved, but yarn elasticity deteriorates

Engineering Contradiction:

Improveenvironmental impactVSAvoidelasticity

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The polyester core contributes elastic and stretchable properties to the yarn structure, compensating for the limited elasticity of recycled cotton fibers. This composite approach maintains environmental sustainability through high cotton content while adding desirable elastic characteristics.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentEP4450688B1A 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 yarn comprising a filament core and a staple fiber sheath, said staple fiber sheath comprises at least 95% by weight of, or consists of, a blend of first fibers and second fibers, wherein said first fibers are natural cellulosic fibers and said second fibers are regenerated cellulosic fibers, characterized in that: the weight ratio of said first fibers to said second fibers is in the range of 70/30 to 80/20, preferably said ratio being about 75/25; the average length of the fibers of the sheath is in the range of 10 to 25 mm, preferably 12 mm to 20 mm; the 5%(n) index of the fibers of the sheath is between 25 mm and 40 mm, preferably in the range between 28 and 36 mm, more preferably between 30 and 34 mm; the short fiber content SFC(n) of the sheath is between 30% and 70%, preferably between 40% and 60%; and said filament core comprises a plurality of polyester filaments.