Desizing Enzymes

Enzymes like heat stable amylase, fungal amylase are used for desizing woven fabrics because of their highly efficient and specific way of desizing without harming the yarn. As an example, desizing on a jigger is a simple method where the fabric from one roll is processed in a bath and re-wound on another roll. First, the sized fabric is washed in hot water (80-95°C) to gelatinise the starch. The desizing liquor is then adjusted to pH 5.5-7.5 and a temperature of 60-80°C depending on the enzyme. The fabric then goes through an impregnation stage before the amylase is added. Degraded starch in the form of dextrins is then removed by washing at 90-95°C for two minutes. The jigger process is a batch process. By contrast, in modern continuous high-speed processes, the reaction time for the enzyme may be as short as 15 seconds. Desizing on pad rolls is continuous in terms of the passage of the fabric. However, a holding time of 2-16 hours at 20-60°C is required using low-temperature alpha-amylases before the size is removed in washing chambers. With high-temperature amylases, desizing reactions can be performed in steam chambers at 95-100°C or even higher temperatures to allow a fully continuous process.

AETL offers products like series of Rapidenz HT as heat stable amylase and Rapidenz Cool as ambient temperature amylase.