Recycled Polyester Yarn Composition for Viscosity-Stable Extrusion

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Solution Overview

Problem

Conventional recycling methods for polyester yarn result in viscosity deterioration and limited applicability due to color discoloration, foreign substance mixing, and high production costs, making them unsuitable for textile materials.

Innovation Solution

A chain extender, carbonyl bis caprolactam (CBC), and a low-melting point alloy agent, copolyester (CoPET), are added to the recycled polyester resin to maintain viscosity and improve extrudability, mimicking the properties of virgin polyester yarn.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If conventional recycling methods are used to process waste polyester, then recycling is achieved, but viscosity deteriorates and color discoloration occurs

Engineering Contradiction:

ImproveviscosityVSAvoidphysical properties

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The patent applies parameter changes by adding chain extenders (such as carbonyl bis caprolactam) and alloy agents (such as copolyester with lower melting point) to the recycled polyester resin during the melting and extrusion process. These additives modify the molecular weight distribution and melting characteristics of the resin, preventing viscosity deterioration and maintaining physical properties equivalent to virgin polyester.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by combining recycled polyester resin with chain extenders and alloy agents. This composite approach allows the recycled material to regain properties similar to virgin polyester, overcoming the inherent degradation from recycling while maintaining economic viability.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If simple extrusion method is used to recycle waste polyester, then production cost is reduced, but the product is not suitable for textile materials due to color discoloration and foreign substance mixing

Engineering Contradiction:

Improveproduction costVSAvoidcolor uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces chain extenders and alloy agents as intermediary substances that facilitate the transformation of waste polyester into high-quality textile materials. These intermediaries act as modifiers that prevent direct negative effects of recycling (color discoloration, viscosity loss) while enabling the production of suitable textile products.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If depolymerization method is used to regenerate polyester, then physical properties are excellent, but productivity is reduced and recycling costs are expensive

Engineering Contradiction:

Improvephysical propertiesVSAvoidrecycling efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent changes the processing parameters by using mechanical melting and extrusion combined with chemical additives (chain extenders and alloy agents) instead of traditional depolymerization. This approach maintains excellent physical properties while significantly improving productivity and reducing recycling costs through a more efficient process.

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 method enhances the extrusion process, reduces production costs, and maintains the physical properties of recycled polyester yarn, making it suitable for textile applications while being environmentally friendly.

Implementation Method 1

adding a chain extender, carbonyl bis caprolactam (CBC), to the recycled polyester resin to prevent a decrease in viscosity

Methodology Applied

Scientific EffectChain extension:

Implementation Method 2

adding a low melting point alloy agent, copolyester (CoPET), to control the properties of the recycled polyester resin

Methodology Applied

Scientific EffectMelting point depression:

Implementation Method 3

extruding the melt to which Carbonyl bis caprolactam (CBC) is added as a chain extender

Methodology Applied

Scientific EffectExtrusion: Extrusion

Data Source

PatentUS20250369160A1Recycled polyester yarn using waste fabric

Publication Date: 2025.12.04 SAMBU FINE CHEM

AI summary

The present invention relates to recycled polyester yarn using waste fabric. The recycled polyester yarn produced by the method, which includes steps of: adding a predetermined chain extender to a polyester resin in which waste fabric woven with polyester yarn is melted to prevent the viscosity of the melted recycled polyester resin from dropping, and by adding a low melting point alloy agent having low melting point and low crystallinity, thereby improving extrusion (workability) in a process of melting and spinning the recycled polyester yarn and having physical properties equivalent to virgin polyester yarn.