Interview with Sandra Haase, Deputy Head of the Accredited Testing Centre and Expert in Textile Physical Testing
Recycled materials are gaining significant importance in the textile industry. Can we generalize the impact of these materials on textile quality?
Sandra Haase: No, it’s difficult to generalize. The quality impact of recycled materials always depends on the intended use of the textile. For clothing, for example, the fiber length is a key factor. When textiles are recycled, the fiber length changes. Mechanical recycling tends to shorten fibers, which significantly affects their subsequent use. Shortened fibers reduce the strength of yarns, as the adhesion between them becomes weaker compared to longer fibers. To counteract this, we can increase the twist in the yarn, but this results in a stiffer texture. Many short fibers also lead to more protruding ends, which can make the surface feel rougher. However, this is still an area where more direct comparisons are needed.
But if recycled materials are used for non-wear applications, such as filling materials or painter's fleece, fiber length is less of a concern.
Can textile-physical tests determine whether a product contains recycled fibers? How accurately can this be determined?
Sandra Haase: t the moment, it’s difficult to say with certainty, especially for textiles with short staple fibers. These fibers don't necessarily have to be recycled; they can be used simply because they’re cheaper. For example, short-staple cotton is less expensive than long-staple cotton, which is of higher quality.
Microscopic images can offer some clues. Mechanical recycling can cause damage to the fibers, which wouldn't occur during the production of new fibers. This mechanical damage often weakens the fibers, reducing the strength of the fabric. This kind of testing is useful when checking the quality of textile products, for example, during supplier evaluations before products are resold or used.
Is it possible to verify if a product is genuinely made from 100% recycled textile fibers, if claimed in terms of sustainability?
Sandra Haase: Currently, it's not possible to do this with absolute certainty. We rely on supplier certificates for verification. Research in this area is still in its early stages. This is particularly challenging for chemically recycled fibers. As an accredited testing center, we collaborate with the research and development department at TITV Greiz to help develop methods to determine this with greater accuracy.
Is it possible to verify if a product is genuinely made from 100% recycled textile fibers, if claimed in terms of sustainability?
Sandra Haase: Currently, it's not possible to do this with absolute certainty. We rely on supplier certificates for verification. Research in this area is still in its early stages. This is particularly challenging for chemically recycled fibers. As an accredited testing center, we collaborate with the research and development department at TITV Greiz to help develop methods to determine this with greater accuracy.
Do recycled textiles perform differently from conventional textiles in other tests?
Sandra Haase: It’s possible, though it’s difficult to make a broad statement. For instance, color fastness, such as light fastness or wash fastness, could be somewhat lower in recycled textiles. The surface roughness of the fabric could also impact its UV protection factor, potentially decreasing it. However, there’s a lack of direct comparisons and more research is needed.
As the use of recycled fibers continues to grow, the need for more advanced testing methods increases. Our collaboration with TITV Greiz is beneficial in developing new test methods that can help address these challenges.
Register now: Free webinar on The Impact of Recycled Materials on Textile Quality
