Sizing Ingredients

Sizing Ingredients
Definition of sizing ingredients
The fundamental objectives of the sizing can be achieved only by impregnating the yarn with the appropriate size mixture consisting of various ingredients in suitable proportion. Each ingredient should impart a particular property to the yarn. Accordingly there are two types of ingredients, namely the primary and secondary ingredients. The primary ingredients are those that are essentially required in the size paste where as the secondary ingredients are those that may or may not be added to the size mixture according to the requirements. The primary ingredient is the main ingredient and it helps to give additional strength to the yarn and also improves its abrasion resistance. The other ingredients

The adhesives produce a film on the yarn which is rather stiff and thus renders the yarn inflexible. Hence in order to make the adhesive film flexible or pliable, the softener is added. Another problem is that the adhesive film on the yarn is not smooth i.e. has rough or uneven surface. This tends to generate frictional forces between neighboring warp threads in the loom during shed formation and also between yarn and certain loom parts such as reed, heald eyes etc. The effect would be that the rough coating of size would come off the yarn and subsequently lead to yarn breakage in the loom. Therefore it is necessary to make the yarn surface smooth. The softener thus performs the dual function making the yarn flexible and smooth. In other words it also acts as a lubricant. Softeners/lubricants used are the following

Deliquescents
These are basically hygroscopic agents and therefore are also called humectants. They help the sized yarn to regain its moisture and flexibility. In other words the deliquescent prevent the yarn from over drying and becoming brittle, by retaining the moisture in the cotton yarn in the required level of 8-10% and thereby maintain the flexibility of the yarn. These are, however, not required in modern sizing machines that are equipped with moisture controllers. The various types of deliquescent that have been used in sizing are Zinc chloride, magnesium chloride, Glycerin etc. Antistatics
Though the antistatic agents are considered to be under the category of secondary ingredients, they are of importance in the sizing of synthetic hydrophobic that are prone static electricity. Fibres such as polyester, nylon, cellulose acetate are highly prone to static electricity. The static charges generated create problems in the subsequent processes, difficulty in unwinding of the weaver’s beams, cloth rolls, and in extreme cases can even cause fire hazards. Hence it becomes necessary to control the static charge generation. The antistatic agents used are glycerol, polyethylene glycol, lissapol NX. Out of these Lissapol NX is the best. Besides, there are also several types of antistatic agents that may be of anionic, cationic, and non ionic or amphoteric in