engleski

Different Yarn Behaviours During the Abrasion Process

Yarn abrasion resistance is a significant property for the quality of the woven fabric production process. In the weaving process, the yarn passes through various metal elements on the loom, in a state of high tension and continuous cyclic stresses. The geometry of the staple yarn can be described as an elongated cylindrical shape of a very relief and rough surface conditioned by the number of twists and yarn hairiness (protruding fibre ends). Such structure, under conditions of high cyclic stresses, is subject to various deformations depending on the properties of the yarn itself. There are large number of various methods for determining the yarn abrasion resistance that are based solely on the number of cycles to yarn break. However, none of them provides insight into the structural changes that occur during the abrasion process, while the breakage has not yet occurred. Such changes remain unregistered by standard yarn abrasion resistance methods but have a large impact on the quality of the produced woven fabric. In this paper, the influence of yarns structural characteristics on their behaviour due to abrasion process was investigated. Seven yarn samples (four single and three plied yarns from a polyamide and cotton fibres blend, of fineness: 50, 38.5, 29.5, 20, 15.5x2, 14x2 and 10x2 tex) were tested. Fineness and twist number, as well as unevenness and hairiness were tested on all samples. All yarns are subjected to abrasion cycles on a yarn abrasion device according to standard FZ/T 01058- 1999, „Reciprocating rubbing roller method “. Prior to abrasion was conducted and after 20, 50, 100, 500, 1000, 2000 and 3000 cycles, a microscopic image of five labelled yarns was taken for each sample. Later, the image analysis was conducted where the average diameter of each yarn sample was calculated. The number of cycles at the yarn break was also recorded and the basic statistical parameters were calculated. The results showed that single yarns behave completely differently from plied yarns when subjected to abrasion. In the case of single yarns, the velocity of diameter change is significant in relation to the plied ones. Furthermore, fineness significantly affects the velocity of diameter change (decrease), where the coarser yarn wears faster and consequently the diameter decreases faster. The reason for this may be a higher proportion of longer fibres and a higher number of twists in yarns of greater fineness compared to coarser ones. In the case of plied yarns, there is practically no change in diameter with increasing abrasion cycles number. The behaviour of the plied yarns can be described as the apparent destruction of the structure due to abrasion, where the fibres are no longer parallel to each other but remain within the yarn where the relative diameter of the yarn does not change or is visually even increased. As for yarn breakage due to abrasion, coarser plied yarns withstand more abrasion cycles. As the fineness of the yarn increases and in a case of plied yarn, the abrasion resistance of yarn increases.

Yarn Abrasion, Staple Yarn, Polyamide Yarn, Cotton Yarn, Yarn Structure.

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