PillingPilling Dr. Jimmy Lam Institute of Textiles & Clothing

Agenda What is pilling? Definition Measurement of Pills (Testing) Factors affecting pill formation Yarn (Open-end; Ring spun yarn and air-jet) Fabric (Woven and Knitted fabric)

Pilling The pills are formed during wear and washing by the entanglement of loose fibres that protrude from the fabric surface. Under the influence of rubbing action, these loose fibres develop into agglomerations anchored to the fabric by a few unbroken fibres.

Definition Pilling is a fabric surface fault in which “pills” of entangled fibres cling to the cloth surface, giving a bad appearance to the garment. The entanglements of loose fibres that appear on the fabric surface are called “pills”. The International Fabricare Institute defines pilling as “the formation of small tangles of fibres or balls on the surface of fabric”. Pilling changes the appearance and texture of the fabric.

Pilling appearance

Measurement of Pills The measurement of pills is in two stages. The first stage is the formation of pills by means of laboratory-test apparatus. The second stage is the evaluation of pills (subjectively by experts) Objective methods characterize pills in terms of their number, weight and size. The combination of counting the pills as a measurement of pilling propensity and weighting the number with respect to their size is quite complex.

Pilling More definition Pilling is a condition that arises in wear due to the formation of little “pills” of entangled fibre clinging to the fabric surface giving it an unsightly appearance. Pills are formed by a rubbing action on loose fibres which are present on the fabric surface. Pilling was originally a fault found mainly in knitted woolen goods made from soft twisted yarns. The introduction of man-made fibres into clothing has aggravated its seriousness. The explanation for this is that these fibres are stronger than wool so that the pills remain attached to the surface rather than breaking away as would be the case with wool.

Pilling Tester Random Tumble Pilling Tester ICI pilling box tester –During testing, apiece of fabric is sewn in place firmly round a rubber tube. It is rotated in the pilling box at 60r/min for 5 hours. –After tumbling, the extent of pilling is assessed visually by comparison with arbitrary standard. Martindale Abrasion Tester (for both knitted and woven fabric)

Atlas Random Tumble Pilling Tester

ICI Pilling Box

Factors affecting pilling A) Yarn type Spinning technique affects the pilling. Ring spun yarn is, in general, more resistance to pilling than open-end-spun yarn. Ring spinning gives a better fibre control (fibre orientation) than open-ended spinning (loose and random arrangement) results in lower pilling. Air-jet spun yarns, however, give a much better pilling control than both ring and open-ended spinning. The best pill-resistant is air-jet spun yarn, followed by ring spun yarn and open-ended yarn

B) Other yarn variables 1.Yarn count 1.In a study of knitted fabric, pilling is observed to be less for yarns of finer counts. 2.This parameter is also found to be less for fabric produced with higher machine gauge 2.Yarn Twist 1.The higher the twist in yarn, the less is the pilling because of the compactness and because there is less protruding fibre in the yarn. 2.Doubled yarn gives less pilling than singles yarn

C) Fabric type 1.Knitted fabrics tend to pill more readily than woven fabrics. 2.Since knitted constructions are composed of a series of loops, a greater amount of yarn surface is exposed, making them more susceptible to abrasion in wear. 3.Moreover, knitted fabrics are more often constructed of low-twist yarns made of staple fibres to give a soft, bulky feel and appearnace. 4.Again, the staple fibres have a greater chance of working their way to the surface of fabric to form pilling 5.Dry relaxed knitted fabrics made from yarns with a higher proportion of acrylic fibres exhibit a greater pilling tendency. The incidence of pilling considerably reduces with an increase in twist and the tightness factor after full-relaxation treatments

E) Weave Structure The twill-woven fabric gives substantially more pills than the plain-woven fabric. The greater number of interlacings and short- lengths in the plain-woven fabric probably reduce the opportunity for the free ends to emerge on the fabric surface and thus reduce pilling. The long floats in a twill weave expose longer lengths of fibres to the surface and increase the chance for pilling. This means that pilling can be reduced by the correct choice of weave

Discussion What is pilling? What are the effects of yarn count and yarn twist on pilling? Why knitted fabric tends to pill more often than woven fabric? Which woven structure will cause more pilling, plain weave or twill weave?

Reference Pilling by J.O. Ukponmwan Textile Progress, Vol 28, No. 3 by Textile Institute (TS1300.T515, V. 28, No. 3) Physical testing of textiles, B.P. Saville, the Textile Institute