Modacrylic, PVC, and Polyester Fiber Separation by Buoyancy

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Solution Overview

Problem

The increasing demand for recycling artificial hair fibers, particularly modacrylic, polyvinyl chloride, and polyester fibers, is hindered by the lack of efficient and cost-effective methods to separate these fibers, which are often mixed together in discarded products.

Innovation Solution

A method utilizing a liquid mixture of calcium chloride, a nonionic surfactant, and water is employed to separate these fibers based on their specific gravities, with optimized concentrations and specific gravities for effective separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional fiber separation methods are used, then fiber separation can be achieved, but the process becomes complex and costly

Engineering Contradiction:
Improveseparation process simplicityVSAvoidseparation system complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent changes the density parameter of the separation liquid by dissolving calcium chloride in water to create a liquid with specific gravity of 1.35 or higher. This parameter change enables effective separation of modacrylic fiber (specific gravity 1.18-1.25) from other fibers like polyester (specific gravity 1.38-1.40) and polyvinyl chloride (specific gravity 1.35-1.45), simplifying the separation process while maintaining effectiveness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a calcium chloride solution as an intermediary separation medium. This liquid mediator has a specific gravity (1.35 or higher) that falls between the specific gravities of modacrylic fiber and other common synthetic fibers, allowing modacrylic fiber to float while other fibers sink,从而实现 effective separation without complex equipment

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If fiber recycling is implemented, then environmental benefits are achieved, but effective separation of mixed fibers is difficult

Engineering Contradiction:
Improverecycling effectivenessVSAvoidfiber separation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent utilizes the specific gravity parameter difference between fibers to achieve reliable separation. By setting the separation liquid's specific gravity to 1.35 or higher, modacrylic fiber reliably floats while polyester, polyvinyl chloride, and other fibers sink, ensuring consistent and effective recycling separation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a hydraulic principle using a calcium chloride solution as the separation medium. The liquid medium exploits density differences to automatically separate fibers through buoyancy forces, making the recycling process easier to operate without requiring complex mechanical separation systems

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

This method enables simpler and lower-cost separation of modacrylic, polyvinyl chloride, and polyester fibers, allowing for their recovery and reuse in new products.

Implementation Method 1

separating a modacrylic fiber, a polyvinyl chloride fiber and a polyester fiber based on their differences in specific gravity

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentUS12442110B2Method for separating fibers and method for producing modacrylic fiber, polyvinyl chloride fiber and polyester fiber
Publication Date: 2025.10.14 KANEKA CORP

AI summary

A method for separating fibers that separates a modacrylic fiber, a polyvinyl chloride fiber and a polyester fiber and a method for producing fibers using these fibers obtained by the method for separating fibers are provided. A method for separating fibers contained in a fiber mixture from the fiber mixture, includes a step of mixing the fiber mixture containing at least two selected from a modacrylic fiber, a polyvinyl chloride fiber and a polyester fiber, and a liquid mixture containing calcium chloride, a nonionic surfactant and water. A method for producing a fiber includes a separation step of mixing a fiber mixture containing at least two selected a modacrylic fiber, a polyvinyl chloride fiber and a polyester fiber, and a liquid mixture containing calcium chloride, a nonionic surfactant and water, and a step of spinning a raw material obtained from a fiber separated in the separation step.