Recycling Waste Fabrics to Plastic Granules

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Solution Overview

Problem

Current recycling methods for synthetic textile waste are complex, costly, and lead to polymer degradation due to thermomechanical processes, making it economically unprofitable and limiting the recycled material's application.

Innovation Solution

A method involving sorting waste fabrics rich in thermoplastic polymers, compacting them under controlled heat and pressure, grinding the compacted slabs into flakes, and then extruding these flakes to produce granules without prior fraying or pulverization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional fraying/grinding processes are used to recycle synthetic textile waste, then fibre can be obtained for recycling, but the process becomes complex and costly with significant impact on recycling costs

Engineering Contradiction:
Improverecycling process simplicityVSAvoidrecycling equipment complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the fraying step from the traditional recycling process. By directly compacting整块 fabric waste into slabs without fraying, the process removes unnecessary complexity while maintaining recycling effectiveness. The fabric is compacted in its original form and then ground into flakes, achieving simplification without sacrificing material recovery.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the recycling process into distinct stages: compaction of整块 fabric into slabs, grinding of slabs into flakes, and extrusion of flakes into granules. This segmentation allows each stage to be optimized independently, reducing overall process complexity compared to traditional continuous fraying-grinding-extrusion methods.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If grinding and carding steps are applied to recycle textile waste, then fibre fractions can be obtained, but shorter fibre fractions are generated than the originals reducing material quality

Engineering Contradiction:
Improvefibre length controlVSAvoidfibre length consistency
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The invention performs preliminary compaction of整块 fabric waste into dense slabs before grinding. This pre-compaction step consolidates the fabric structure, allowing subsequent grinding to produce more uniform flakes with consistent dimensions. The preliminary organization of material structure prevents excessive fibre shortening during size reduction.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If thermomechanical recycling process with melt blending is used, then regranulation can be achieved, but operational complexity increases due to contamination and feeding difficulties

Engineering Contradiction:
Improverecycling output efficiencyVSAvoidmaterial feeding ease
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The invention changes the physical state and density parameters of the textile waste through controlled compaction. By compressing loose fabric into dense slabs with controlled porosity, the material transitions from a difficult-to-feed fluffy state to an easily-handled solid slab form, which is then ground into uniform flakes suitable for extrusion feeding.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces intermediate forms (slabs and flakes) between the original fabric waste and the final granules. These intermediate forms serve as mediators that bridge the gap between loose textile material and extrusion-ready feedstock, simplifying the feeding process while maintaining productivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If adequate drying process is applied before extrusion to prevent hydrolysis, then polymer degradation is reduced, but significant energy consumption is required

Engineering Contradiction:
Improvepolymer quality maintenanceVSAvoiddrying energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention skips the traditional extensive drying step by rapidly processing material through compacting and grinding stages that occur quickly at controlled temperatures. The process rushes through the potential hydrolysis risk period by minimizing the time material spends in vulnerable states, reducing the need for energy-intensive prolonged drying while maintaining polymer quality.

Inventive Principle:
Principle #21Skipping (Rushing through)

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 simplifies the recycling process, reduces material degradation, and produces high-quality granules suitable for common plastic manufacturing processes, such as extrusion, thermoforming, and injection molding, while being economically advantageous.

Implementation Method 1

compact the selected material by heating at a temperature between 150°C and 310°C and pressure until a slab of recycled predominantly plastic material is obtained

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

compact the selected material by heating at a temperature between 150°C and 310°C and pressure until a slab of recycled predominantly plastic material is obtained

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

The flakes thus obtained are then extruded to produce granules

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4494833A1Method for producing plastic granules from recycling of waste fabrics and/or yarns
Publication Date: 2025.01.22 SPIN PET SRL
  • EP4494833A1 patent drawingFigure 1~2
  • EP4494833A1 patent drawingFigure 3
  • EP4494833A1 patent drawing

AI summary

A method for the production of granules in recycled plastic material starting from waste fabrics and/or yarns, comprises the steps of: sorting (100) a quantity of waste fabrics and/or yarns consisting of at least 85% by weight of thermoplastic and/or elastomeric polymers; compacting (200) the selected material by heating at a temperature between 150°C and 310°C and pressure until a slab of predominantly plastic material between 0.5 mm and 10 thick mm is obtained; grinding (300) the slab of predominantly plastic material so as to obtain flakes of predominantly plastic material having a bulk density between 0.3 kg/liter and 0.8 kg/liter; extruding (400) the flakes of predominantly plastic material so as to obtain granules of predominantly plastic material. The method eliminates the conventional fraying or grinding steps typical of conventional processes and allows to obtain a recycled material that is not degraded by the fact of having been brought to temperatures higher than the melting temperature and of having been subjected to shear stresses.