Types of Yarns UNIT. Structure. Learning Objectives. Unit Preview

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1 162 Fashion Garment Making UNIT 8 Structure 8.0 Introduction 8.1 Production of yarns 8.2 Classification of Yarns 8.3 Yarn fineness Count, Denier 8.4 Yarn Twist Learning Objectives To understand the production process of staple and filament yarns. To study about the classification of yarns To identify different types of novelty yarns. Identify the application area of novelty yarns To understand the yarn counting system and yarn twist Unit Preview Types of Yarns The hand values and performance of the fabric is based on the type of yarns used. The yarns are classified depending on the length of the fibres and number of parts present in the yarn. The different count are made by using different type of fibre based on its end uses. The novelty and texturised yarns are gnerally used for the ornamentation purposes and create specific effect.

2 Paper - II Fundamentals of Textiles Introduction The definition of yarn is A yarn is a continuous strand of textile fibers, filaments, or material in a form suitable for knitting, weaving or otherwise intertwining to form a textile fabric ASTM There are different types of yarn, each having its own characteristics. These characteristics vary according to the construction and the treatment given in the manufacture of the yarn. Yarns play a very important in determining the hand and performance of the fabric. Yarn is the generic name for the assemblage of fibers that is laid down or twisted together. As discussed earlier, there are staple and filament yarns that are used in clothing. First let us see about how the staple and filament yarns are manufactured. 8.1 Yarn Manufacture a. Staple yarn The short staple fiber are spun into yarns by a process called mechanical spinning. The steps in the processing are preparation, forming the laps, carding, doubling, combing, drawing, roving, and spinning. The detailed procedure is discussed in chapter 3 under spinning of cotton. The same procedure is followed for all staple fibers except for some changes in the preparatory steps. Filament yarn is also sometimes purposefully cut to staple length and spun in the mechanical spinning method to obtain yarn with cotton / wool feel. b. Filament yarn manufacture: All the synthetic fibers are filament fibers and their spinning method is different from the staple spinning. The extruder and spinneret are used for the chemical spinning. There are three methods of chemical spinning like wet, dry and melt spinning. All fibers upon extrusion from spinneret are drawn in their gel stage to make the molecules oriented well and later can be used as such or textured for decorative effects. Wet spinning It is done for acrylic rayon and spandex. The chemicals are used to dissolve the materials and the fiber spun in chemical bath shown in fig no 8.1. The fiber solidifies with coagulation by bath. It is the oldest and complex process. These filament strands are then drawn out of the bath, washed and dried before being wound on the spools. Washing and bleaching is required before the fibers used.

3 164 Fashion Garment Making Dry spinning Fig 8.1 Wet spinning This spinning is followed acetate, acrylic, modacrylic and spandex. The solvent dissolves the raw material and the fiber spun into warm air. Later the solvent is evaporated. The air reacts with the extruded streams causing them to solidify twisted and/or processed further and then wound onto spools.. The fiber does not require any washing. It is the direct process and seen in fig no.8.2 Warm air flow Melt spinning Fig 8.2 Dry Spinning This is used to spin the nylon, polyester, and olefin fibers. It is a direct process and least expensive process. The raw material is melted in autoclave and spun into yarn. The fiber solidifies by cooling. The process may not require any solvent and get different fiber shapes based on the spinneret shape. The extruded stream cool and solidify into continuous filaments and are then drawn

Paper - II Fundamentals of Textiles 165 out of the chamber twisted and/or processed further and subsequently wound onto spools. The melt spinning diagram shown in fig 8.3 Cool air flow 8.

According to Length of Fibers Present in Yarn Yarns can be broadly classified as staple and filament yarns. Staple yarn: Spun yarns are made from staple fibers that are twisted together.

4 Paper - II Fundamentals of Textiles 165 out of the chamber twisted and/or processed further and subsequently wound onto spools. The melt spinning diagram shown in fig 8.3 Cool air flow 8.2 Classification of Yarns Fig 8.3 Melt Spinning Yarns are classified based on length and its parts. Fig 8.4 Fig 8.4 Classification of yarns I. According to Length of Fibers Present in Yarn Yarns can be broadly classified as staple and filament yarns. Staple yarn: Spun yarns are made from staple fibers that are twisted together. Filament yarn: the filament yarns are longer in length. The range of filament yarns is as diverse as that of spun staple yarns. The filaments yarns are divided into two types flat continuous filament, Textured continuous filament

166 Fashion Garment Making II. According to the Number Parts Present in Yarn 8.2.1 Simple Yarns Fig 8.5 Classification of yarns based on structure A simple yarn is alike in all its parts.

5 166 Fashion Garment Making II. According to the Number Parts Present in Yarn Simple Yarns Fig 8.5 Classification of yarns based on structure A simple yarn is alike in all its parts. It can be described as spun or filament yarn based on the length of fibers present. Simple yarns are classified as shown in diagram A single yarn is the product of the first twisting operation that is performed by the spinning machine. 2. A ply yarn is made by a second twisting operation, which combines two or more singles. Each part of the yarn is called a ply.it s mostly used in warp direction and found in men s shirts and sweaters. The two ply and three-ply yarns are found in sewing threads. Single Pl y Cord Fibres (a) Single yarn (b) Two-ply yarn (c) A cord yarn Single Fig 8.6 Classification of yarns based on parts Single

6 Paper - II Fundamentals of Textiles A cord/ cable is made by a third twisting operation, which twists ply yarns together. Some types of sewing threads ands some ropes belong to this group. Cords are generally not used in apparel fabric, but used in industrial weight fabrics The double yarns consist of two or more single strands treated as one in the weaving process, but the strands are not twisted together Novelty Yarns/Complex Yarns A novelty yarn is yarns that are irregular at regular intervals. Fancy yarns have been more common in drapery and upholstery fabrics than apparel fabrics. The special arrangement is required for making the curled, twisted and looped yarn. The yarns are used in weft direction of the fabric. The figure shown in fig no.8.7. a. Types of Novelty Yarns Fig 8.7 Novelty yarns 1. Slub yarn: This is a thick and thin yarn made by varying the amount of twist in the yarn at regular intervals shown in figure 8.8. They are found in drapery and upholstery fabrics. Fig 8.8 Slub yarns

7 168 Fashion Garment Making 2. Thick and thin yarns: These are similar to slub yarns but these are made from filament fibers shown in figure 8.9. The pressure forcing the spinning solution is varied the filament are thick in some places and thin in some. Fig 8.9 Thick and thin yarns 3. Knot The prominent bunches of one or more of the component yarn present at regular or irregular intervals. 4. Cloud: A two colored yarn, in which both yarns take it in turn to obscure or cloud the other, giving the appearance of an intermittent color change shown in figure Fig 8.10 cloud yarns 5. Spiral or cocksrew / Eccentric: It is made by twisting together two piles that differ in size, type, or twist shown in figure These two parts may be delivered to the twister at different rates of speed. Fig 8.11 spiral yarns 6. Chenille Yarn: These create special effects. Chenille means caterpillar in French seen in fig8.12. The yarn has a cut pile effect. The weft is inserted in normal manner. These are cut into wrap way threads Textured yarns Fig 8.12 Chenille yarns Texturizing is a treatment usually given to a manmade filament, after which it becomes curly or acquires some forms of loops, coils or crimp seen in diagram These are filament or spun yarns with notably greater apparent volume

Paper - II Fundamentals of Textiles 169 than a conventional yarn. Fabrics made from theses yarns maintain their original size and shape during wear and care.

8 Paper - II Fundamentals of Textiles 169 than a conventional yarn. Fabrics made from theses yarns maintain their original size and shape during wear and care. Curled Yarn High Bulk Yarn Crimp yarn Coiled Yarn 8.3 Yarn Fineness Fig 8.13 Textured yarn types Yarn number varies and it differs according to the kind of fiber. The spun yarn measured in indirect system and indicates the finer the yarn the larger the number. The count is based on the number of hanks (1 hank is 840 yards) in 1 pound of yarn. The direct system is used for filament yarn and determined in denier system expressed in terms of weight per unit of length. It shows that the finer the yarn, the smaller the number. The International Organization for Standardization has adopted the Tex system, which determines yarn count or number in the same way for all fiber yarns and uses metric units (weight in grams of 1 thousands meters of yarn.) 8.4 Yarn Twist Twist is the spiral arrangement of the fibers around the axis of the yarn. The number of twists is referred to as turns per inch Direction of Twist Z-twist S-twist Z-twist S-twist Two-ply Fig No 8.14 Yarn twist direction The direction of twist is described as S-twist and Z-twist. S-twist - when held in a vertical position, the spirals conform to the direction of slope of the

9 170 Fashion Garment Making central portion of the letter S, Z-twist - the direction of spirals conforms to the slope of the central portion of the letter Z, Z-twist is the standard twist used for weaving yarns. The direction are shown in fig Types of Twist The low twist had 2-3 turns per inch and this type of twist allows for napping the fabric. The average twist gives warp yarns maximum strength is referred to as standard warp twist. The hard twist has twists which brings fibers closer together and make the yarn more compact. They are shown in diagram Fig 8.15 Types of Twist Activity Remove the yarn and ravel out the plies Make them to understand end use of each yarn I. Test your understanding True or False 1. The spun yarns are made from the staple fibers 2. The ply yarns are made by twisting two or more single yarns together 3. The ply yarns are generally used for making the industrial fabrics 4. The double yarns are used for making the ornamental effect on the fabric 5. The ply yarns are mostly used in weft direction II.Test your understanding Match the following Name of the process Description Spiral yarn ( ) 1. Third twisting Ply yarn ( ) 2. Two plies are twisted together Cord yarn ( ) 3. Double twisting Novelty yarn ( ) 4. One or more bunches at regular interval Knot yarn ( ) 5. Irregular yarn at regular intervals

10 Paper - II Fundamentals of Textiles 171 Short Answer Type Question 1. What is ply yarn? 2. What is yarn twist? 3. What are the types of yarn twist? 4. Write short note about novelty yarn. 5. What is Tex system? 6. What is ratine? 7. How does the cloud yarn look? 8. How does the staple yarn count measured? 9. What type of twist used in napped fabric? Long Answer Type Question 1. Classify the types of yarn with suitable diagram. 2. Write down the types of novelty yarns with diagram 3. How does the yarn count are measured by using different system? 4. What is the difference between the simple and novelty yarn. 5. Why the twist is important for fabric durability? 6. What are the factors influence the yarn quality? I. Test your understanding (Answers) 1. True 2. True 3. False 4. True. 5. False II.Test your understanding 1.( 2 ), 2.( 3 ), 3.(1), 4.( 5 ), 5.( 4)

LESSON 6 PRODUCTION OF FANCY YARNS STRUCTURE 6.0 OBJECTIVES 6.1 INTRODUCTION 6.2 STRUCTURE OF FANCY YARNS 6.3 SOME EXAMPLES OF FANCY YARNS

LESSON 6 PRODUCTION OF FANCY YARNS STRUCTURE 6.0 OBJECTIVES 6.1 INTRODUCTION 6.2 STRUCTURE OF FANCY YARNS 6.3 SOME EXAMPLES OF FANCY YARNS 6.4 MANIPULATION OF FIBRE CHARACTERISTICS 6.5 MANIPULATION OF