Dokuma kumaşlarda boncuklaşma ve ölçüm metodlarının karşılaştırılması
Dokuma kumaşlarda boncuklaşma ve ölçüm metodlarının karşılaştırılması
|Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1994
|Boncuklaşmanın sebeplerinin ve ölçüm metodları arasındaki farklılıkların, sonuçlara göre olan etkisinin bilinmesi, kumaşların kalite kontrol değerlendirmeleri açısından önemlidir. Numuneler en az 24 saat kondisyonlandıktan sonra kumaş analizleri yapılmıştır. Karışım oranlarına göre sınıflandırılan kumaşların boncuklaşma özelliklerinin ICI ve IWS Boncuklaşma Kutu ve Martindale Aşındırma Test Cihazları kullanılmıştır. Bu cihazların standart deney numuneleri şeklinde hazırlanan kumaşlar, ICI cihazında 18000 Devir/ dak., IWS cihazında 14400 Devir/dak. ve Martindale cihazın da, 0-10bin-20bin devirlerdeki numune ağırlıkları ölçülmek suretiyle, 20000 Devir/dak. aşındırma işlemlerine tabi tutulmuşlardır. Standart boncuklaşma fotoğraflarından elde edilen sonuçlara göre yapılan değerlendirmeler, ICI ve IWS sonuçlarının birbirlerine genelde yakın, Martindale sonuçlarının ise daha iyimser olduğu bulunmuştur. Sonuç olarak, kumaş özelliklerinin boncuklaşma üzerine önemli ölçüde et kili olduğu ileri sürülmüştür.
|In this study, the effect of structure of fabrics on pilling and compairing the measuring methods have been studied. In the second chapter, scientific investigation on this subject has been given. The process of pilling results in a degradation in the appearance and handle of the textile article are con cerned. The severity and duration of this process very considerably form a localized minor disturbance on the fabric surface to a compromise the acceptability and performance of the product. The severity of pilling is most often judged in terms of the numerical density of pills on the fasric surface, and fabrics that pill rapidly have a high rate of pill wear-off are likely to be consi dered better from an aeshetic wiew point than fabrics with a low rate of pilling but a lower rate of pill vear- off. Although the problem of pilling has probably been recognized for a long time, it receved little mention in the literature prior to' 1950 and apparenly was accepted as a normal feature of the effect of wear on textile products. The introduction of synthetic fibres to the market place caused two main changes, first the severity and largevity of the pilling. was greatly increased and second the. brandname marketing of the synthetic fibres ensured that the concumers know exactly who to blame for the deg radation in performance. VI It is clear that the increased strength and flex of synhetic fibres and greatly the rate of pill wear-off and result in pill densities are greatly increasing pill life. For this reason, the synthetic fibre manufacturers have paid particular attention to methods of pill control that increase the rate of pill loss, aswell as to methods of increasing the coefficient of friction of the fibre within the yarn structure with the aim of reducing fibre movement. The majority of synthetic fibres with low pill properties have a lower than normal tenacity for their jeneric class and in particular have low wlex lives. The tenacity and rigidity of fibres affect the fuzz development phase and subsequent fuzz entanglement. The fibre properties associated with different stages of the pilling mechanism were tensile strength, percent elonga tion, flex abrasion, bending rigidity, fibre denier and the shape of fibre. The fibre with high tenacity and low bending rigidity generated high fuzz densities and high rate of initial pill developments. Oh the other hand, ihgh tensile strength and flex decreased the rate of pill wear-off. An ealier study indicated that polyester and nylon had moderate rates of pill development but very low rates of pill wear-off due to their high tensile strength in all man?-made and blended products. The demand for softer, thinner and lighter garments has been met by reducing twist factor and fabric cover factors and both these changes increase the tendenncy to pill. There is no doubt that the formation and wear-off a high density of pills remove significant quantities of fibre from the fabric surface, but if such a large area of garment surface, it will not necessarily in fabric break down. Pilling is generally concerned to be a self limiting process occuring in four main stages, fuzz formation pill entanglement and growth and pill wear-off. The intial effect of abrasion on the surface of a fabric is the for mation of fuzz as a result of two processes, the brushing up of free fibres end not enclosed within the yarn struc ture and the conversion of fibre loops. A criticial fuzz height dependent on the fiber charac teristic before pill formation causes fuzz entanglement. Motoji and Tsujimoto studied fuzz entanglement using time lapse techniques and a rotary abrading that the process was initiated by a "node" formed by a knot or a piece of Vll foreign matter. Cooke undertook a series of time lapse experiments using a Martindale Abrasion Tester as a pill generator. The fibre entangglement occured between fibres in the normal fuzz array. In the process of pill growth pill anchors are heavily fatigued. The anchor fibres are being progressively drawn up in to the pill body. The process of anchor fatigue often start low down the fuzz array to close to the yarn surface where the fibres are securely held. Fuzz generation occurs first and it is complete before pilling takes place. Pill growth then occurs a result of the entanglement of this strictly limited reserve of fuzz and the process of anchor brekage removes the majority df the pills from the fabric surface. Pill wear-off will occur because of the fracture of the anchors as a result of fatigue or other damages or because of the anchor fibres being pulled out, or as a result of a combination of both factors. The figure 1 shows that the pull out/roll-up mechanism of pill growth. Fibre remova uelecllve nitration and pilling I by <^ KtUfe removal by multiple fatigue cracking Rg.f Diagram illustrating the pull-out/roll-up mechanism of pill growth Fig:l. The there stages in pill life have been well documen ted for a variety of fibres and. Gintis and Mead have listed the fibre properties that effect the stages of fuzz formation, entanglement into pills and finally pill wear-off. Recognizing the similitary between pill build up and decay characteristics and the kinetic treatment of reactive species in chemical reactions. Brand and Bohmfolk proposed a mathematical model of pilling. Canti and Tassinari simplified the kinetic model of them. vixi This model is based an an inital amount of pillable fuzz, forming pills at a rate and wear-off a decay rate. In order to reduce the amount of pilling fabrics are applied to a number of physical and chemical processes. By these processes, a decrease in surface hairiness of a fabric and^ an increase in friction between the fibres are achived. Some kinds of instruments and developed to deter mine the pilling effect. These instruments are used as a pill generator. The most widely known of these are ron- dom tumble pilling tester (R.T.P.T.), accelerator, univer sal stoll wear tester, ICI and IWS box pilling and Martun- dale testers. ICI and IWS box pilling testers and Martindale abra sion testers were used in these study. A total of 55 fabric used as experiment samples with blends of 67% poy- yester-33% viscose,, 50% polyester-50% viscose, 50% woll- 50% polyester, 70% polyester-30% viscose, 67% polyester-33 % cotton, 65% polyester-35% cotton. For each fabric tested in all there instruments, pil ling result were compared and then effect of the fabric structure on pilling is investigated. Before analysing all fabrics were conditional at least 24 hours. After classifying the fabric according to their blends, ICI and IWS box pilling testers and Martindale abrasion tester were used for determining pilling properties. Each fabric was prepared as the standart test samples of these methods, The fabrics were tested 18000 cycle/min. in ICI box pilling tester and 14400 cycle/min. in IWS box pilling tester weight loses were measured for all fabrics abraided at 0.10000 and 20000 rugs/min.in the Martindale abrasion tester. The pilling tendency of a fabric tested on ICI and IWS is highly corrolated. On other hand, Martindale abrasion tester showed less pilling formation compairing with previous two methods. In addition, the properties, the properties of fabrics mostly effect the pilling, especially, fabrics which contain synthetic fibres have ihghly pilled. On the other hand, the fabrics which are made of natural fibres have less pilling. But the finis hing processes are rather effective on the pilling mecha nism for all kinds of fabrics. IX In following studies, at will be my recommandation a) To look into the effec-t of the behavi ur of different types of fibres in the fabrics. b) To choose fabrics which contains synthetic fibres as a test sample. c) To investigate the finishing processes more extensively.
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|Dokuma kumaşlarda boncuklaşma ve ölçüm metodlarının karşılaştırılması