Desizing

Desizing

The gray cotton fabric contains natural as well as those added to the fabric such as size to facilitate weaving.

Desizing

Size normally contains an adhesive (film former) and a lubricant. For cotton fabrics the film former is usually starch or a starch derivative. All starches are, by their very nature, either water-insoluble or only sparingly soluble. For viscose the most important sizing agent is the cellulose derivative carboxymethylcellulose (CMC), which has good water solubility.

 In addition to natural products, such as starch and starch derivatives, synthetic sizes based on styrenemaleic acid copolymers, polyvinyl alcohol, polyacrylates or polyacrylamides are used on polyester/cotton or polyester/viscose, as well as mixtures of starch and polyvinyl alcohol. The synthetic polymer sizes and carboxymethylcellulose are also used on continuous-filament warps made from acetate, triacetate, nylon or polyester. 

The lubricant in a size formulation is usually tallow, but spermaceti, paraffin wax and mineral oils are sometimes employed. These lubricants impart good smoothness and low frictional properties to the yarn and are therefore beneficial for weaving, but they are insoluble in water and difficult to remove from the fibre surface, which can lead to severe problems in desizing.

Several chemical manufacturers offer wax like products that are water-soluble for addition to size formulations to improve suppleness and smoothness of the yarn; being water-soluble these are relatively easily removed during desizing.