TYPES OF YARN (CALSSIFICATION OF YARN)

Classification of yarn- 

STRETCH YARN.

Stretch yarns are frequently continuous filaments synthetics yarns, that are very highly twisted , heat set , and the untwisted pruducing a spiral crimp giving springy character . Although bulk is imported in the process a very high amount of twist is reamquired to produce yarn that has not only bulk but also stretch. 

Spandex is generic term for highly elastic synthetics fibers , composed mainly of segmented polyurethane. Uncover fibers may be used alone to produce fabrics but they impart a rubby feel. For this reason elastomeric fiber is frequently used as the core of the yarn, and is covered with a non stretch origin. Although stretch may be imparted to natural fiber, other properties may be impaired by the process , and the use of an elastic yarn for the core elements that need to process the covering fiber.

image of texture stretch yarn ref by iStock.

Classification based on use fabrics construction.

Almost any textile yarn can be use to produced such interlaced fabrics as woven or knitted types . In weaving , the warp yarn or lengthwise yarns are subjected to greater strength and stress and are usually stronger , smooth , and more even and have higher twist than the weft, crosswise yarn. A sizing (stuffing) material such as starch may be applied to warp yarn , increasing there strength to withstand the stresses of fabrics during construction operations. Weft yarn subjected to little stress during weaving , may be quite fragile.

Warp and weft threads are used in the same fabrics may be of different diameters (count)  producing such special effects as rubbing or carding in the fabric. Special effects may also  be obtained by  combining warp and weft yarn of fiber from different  origin or with different degrees of twist or by introducing metallic threads into weaver's compose of the fiber. 

Yarn for machine knitting are usually loosely twisted because softness is described as knit fabrics.

Yarn used in hand work.

Yarn  used in hand knitting are generally of two or more ply . They  includes types of figuring yarn usually of two or three plys, light to medium in weight and with even diameter (count) is used for various types apparals . Germantown yarn, soft and, thick usually four ply and medium weight frequently used for sweaters and blankets, shetland yarns , fine soft, fluffy and lightweight, frequently two ply used for infant's  and children's sweaters and for shawls, worsted knitting yarn highly twisted and heavy , differing from worsted fabrics by being soft instead of crimp and suitable for sweaters and zephyr yarn, either all wool or wool blended with other fibers, very fine and light weight garments.

Emboridey floss , used in hand embroidery, generally had low twist , is of such smooth filaments ,silk and rayon . Yarn used for crocheting is frequently a  loose cotton of seam and  cord type,  and darning yarns are usually loosely spun .

SEWING THREAD:-

Sewing threads are lightly twisted ply yarns made with strands having equally balanced twist, producing a circular cross section. Threads for use in commercial or home sewing machine and should allow easy movement when tension applied and eas in needle threading  should be smooth to resists friction during sewing should have elaticity to avoide from breaking of stitches or  puckering of  seams and to avoide the braking of stitches or puckering of seams , and should have sufficient strength to hold seams during laundring or dry cleaning and in use.

Threads for specious uses may require appropriate treatment. Garments made of water repellent fabrics , for example may be sewn with thread that has also been made water repellent. Thread is usually subjected to special treatment after spinning and is then wound on spools. Thread size ( count) is frequently indicated on the spool end , and system for indicating degree of fineness vary according to the textile measurement system used locally.

Silk threads has great elasticity and strength combined with fine daimeter . It can be permanently stretched in sewing  and is suitable for silk and wool. Button hole twist is strong , lustrous silk about three times the diameter of normal sewing silk and is used for hand worked button hole , for sewing on buttons and for various decorative effect.

Cotton thread is computable with fabrics made from yarn of plant  origin, such as cotton, and linen, for rayon (made from a plant substance), because it has similar shrinkage characterstics. It is not suitable for most synthetic, which do not shrink ,or for fabric treated to reduce shrinkage . Its low stretch is useful for woven fabrics but not for knit , which require more stretch.

Nylon thread is a strong with great stretch and recovery , does not shrink and is suitable for sheers and for very stretching knots . Polyester threads are similar characterstic and is appropriate for various synthetics and preshrunk fabrics and for knit made of synthetics yarn.

image of sewing thread ref by empress mill.

Ref:-https://www.britannica.com