Abrasion, pilling and garment lifetime: the case of pull-over garments

In the context of circular economy, extending the lifespan of objects is a major leverage effect for reducing their environmental footprint. It often makes it possible to limit incineration and landfill by optimizing reuse and recycling. When it comes to clothing, there are many end-of-life causes [Benkirane], and pilling is one of them, particularly for knitwear. Textiles degrade through wear and tear during use and maintenance leading to aesthetic damage such as pilling. The aim of this study is to propose a methodology for correlating abrasion to the lifespan of pullovers. It is based on the analysis of 28 sweaters from the retail trade. The fabrics were tested in the laboratory by Martindale, using a methodology providing "abrasion profiles" with 6 measurements spread over 7,000 cycles and 2 types of abrasive: SELF and NORM. Abrasion profiles are characterized for each garment, in the form of pilling rating as a function of number of cycles. 3 characteristic profiles were defined based on an unsupervised classification (K-means method): Fragile, Medium, Solid for each abrasive. In parallel with this, wear tests are carried out with a panel of 15 consumers using a predefined procedure involving alternating wear and wash cycles. After each wear test, a pilling score is obtained under the same conditions as for the laboratory tests. Combining these 2 approaches enables us to associate the wear cycles obtained in the laboratory with those obtained with the panel, and thus to establish a correspondence curve between Martindale cycles and the number of wearings. This correspondence differs from profile to profile. For each product class "Fragile, Medium, Strong", the curve of the pilling rating as a function of the number of wears is obtained. The time limit for wear can be defined by the consumer's sensitivity to the presence of pilling. The study shows the relevance of the methodology used, and represents a first step towards associating qualitative measurements with garment lifetimes. Further studies should reinforce this scientific approach, and be complemented by a study of consumer behavior with regard to the defects that cause garments to be discarded.