Uster Introduces Recycled Fiber Matrix to Support Circular Textile Production
Two-dimensional assessment system helps recyclers, spinners and brands evaluate mechanically recycled cotton and identify suitable processing and end-use applications
Uster has developed the Recycled Fiber Matrix, a two-dimensional assessment framework designed to help the textile industry evaluate mechanically recycled cotton fibers and match them with suitable spinning processes and end uses.
The system responds to the variability of recycled cotton, providing objective data on key fiber characteristics to support recyclers, spinners and brands in making informed decisions about material quality, processing and blending.
Assessing the Key Characteristics of Recycled Fibers
Mechanically recycled cotton fibers can vary significantly depending on their source and processing conditions. Uster’s Recycled Fiber Matrix focuses on physical parameters that influence spinning performance and end-use suitability.
Key measurements include:
- Fiber length (L(n))
- Length of the longest 5% of fibers (5% L(n))
- Short fiber content (SFC(n))
The development of the matrix involved testing a significant number of 100% mechanically recycled cotton fiber samples from major recycling regions, including China, India and Europe.
The samples covered greige, colored and bleached recycled fibers, with sources including post-industrial, pre-consumer and post-consumer textile waste.
Uster AFIS 6 Data Supports Matrix Development
Measurements conducted using the Uster AFIS 6 formed the basis for identifying trends incorporated into the Recycled Fiber Matrix.
Based on this testing, Uster developed an application report examining the current state of mechanically recycled cotton fibers and potential challenges associated with their use in spinning.
The matrix remains an ongoing and dynamic process. Uster continues to collect and analyse additional samples from recycling hubs around the world as source materials and processing conditions evolve.
Two-Dimensional Approach to Fiber Classification
The Recycled Fiber Matrix presents AFIS 6 measurements through quality levels ranging from A to D, with colour-coded regions designed for practical application.
The system uses two-dimensional evaluation because mechanically recycled cotton cannot be accurately classified using a single fiber parameter.
For example, one axis may represent a length characteristic such as mean fiber length, while the other may represent a quality-limiting factor such as short fiber content or nep count.
This approach makes it possible to identify interactions between different fiber properties. Two lots with the same mean fiber length, for example, may behave differently during spinning if their short fiber content differs.
Supporting Industrial Processing
The Recycled Fiber Matrix enables AFIS measurements to be translated into defined quality categories, helping customers understand the quality level and limitations of individual recycled fiber lots.
The resulting classification can support bale management and machine settings. It can also help estimate expected short-fiber loads and determine appropriate blending ratios for achieving desired yarn performance.
Uster experts recommend improving fiber sorting by separating bales according to length, source and colour to reduce variability and maintain consistency in important fiber parameters.
Spinning mills can also adapt processing conditions to the specific quality of recycled fibers by adjusting:
- Draft settings
- Twist
- Spinning speed
- Maintenance and cleaning frequency
Blending Recycled and Virgin Fibers
Mixing recycled cotton with virgin cotton or synthetic fibers remains a key strategy for compensating for quality limitations in recycled material.
Uster is currently working on establishing benchmarks for different blend levels and evaluating their subsequent effects on yarn quality.
These benchmarks are intended to further support decision-making around the use of mechanically recycled fibers in yarn production.
Free Application Report Available
Uster has made its Recycled Fiber Matrix application report available as a free download. The educational document includes graphs and illustrations explaining the assessment approach and its practical applications.
The report provides insights for spinning mills, recyclers and brands seeking to assess fiber suitability and optimise processing parameters.
Supporting Textile Circularity
As recycling technologies and fiber preparation methods continue to develop, Uster plans to continue collecting data and updating the Recycled Fiber Matrix.
The company sees ongoing data collection and matrix development as important for improving classification accuracy and supporting the wider use of recycled cotton in textile products while contributing to circularity objectives across the industry.