SPUN SILK

Spun Silk:

           

            Short silk fibres are obtained from damages cocoons (or) while reeling the cocoons. Some amount of fibre at starting and some amount of fibres at ends are wasted to give the short fibre. These fibres can be spun in cotton system to give spun silk threads. Spun silk fabric tends to became fluffy after wearing because the yarn is made-up of short staple fibre.

Weighting of Silk:

·         Many techniques have been advised for increasing the density of silk by artificial means, Tin salts are used for weighting of silk fabrics.

·         Degummed silk is steeped in a solution of tin chloride (or) Stannic chloride and silk filaments absorb some of salt. After washing the silk is steeped in a solution of sodium phosphate. This double steeping process is repeated several times, after which it is soaked in sodium silicate solution.

·         The silk absorbs 25 to 60% of the salt depending upon the type of fabric.

·         Weighted silk fabrics are not strong as those made from pure silk. They have fuller handle which is preferred for certain applications.

·         Weighed silk garments should not be used as underwear.

·         The process of increasing upto 50% of original volume by tin chlorine also serve as giving a special texture to the fabric used for ladies dress material.

·         Weighted silk fabrics are not as strong as those made from pure silk.

·         May have a fuller handle which is preferred for certain applications.

·         Weighted silk garments should not be used as underwear.

Throwing of Silk:

           

            This is the operation of twisting of long filaments of silk into a yarn. Reeled silk is transformed into “silk yarn” by process called “Silk Throwing”. Twist gives cohesion to the thin filaments which are combined together. The number of (Twist per inch) TPI inserted and direction of twist “S or Z” are important.

            The raw silk skeins are soaked in warm water with soap. The softening of the sericin gum assists easy handling of the filament. The skeins are placed on light reels from which the silk is wound on bobbins. The thread is then inspected labeled and packed.

Degumming of Silk:

            The natural gum sericin is normally left on the silk during reeling, throwing and weaving. It acts as a size which protects the fibres from mechanical injury. The gum is removed from the finished yarns (or) fabrics, usually by boiling with soap and water.

Treatment:

                        Soap                -           0.5%

                        Soda ash          -           0.5%

                        Temp               -           90°C

                        Time                -           2 Hours

            After degumming, the silk acquires its beautiful luster and becomes soft. As much as one-third of the weight of fabric may be lost when the gum is removed in this way.

Uses:

            Silk is mainly used for ladies dress material, Silk prevents body heat, it is desirable for winder apparels’. Silk yarn is used to produce fabric as Georette, taffeta, organdy and grenadine.

            Spun silk is used for shantung and pile fabrics for dress trimmings, lining elastic webbing and for velvets for (Belt or straps) umbrella fabrics and for insulative material. Wild silk fabrics are durable and have a coarse irregular surface. Typical fabrics are rayah, shantung tursah and pongee.