Better Sewability of Cotton Knit Fabric Treated with Alkali and Neutal Pectinase

Fabric sewability is the ability of fabric to be sewn without causing sewing problem. Sawing damage is one of the most common sawing problems which trouble the textile and clothing industries. It is attributed to fabric properties, sawing conditions and mishandling. The selection of sewing needle, fineness of sewing thread, relative air humidity, thickness and density of knitted fabric as well as fabric pretreatment and finishing play a significant role in the technological process of sewing. It is well known that raw cotton is highly hydrophobic. Standard procedures for cotton scouring involve alkali treatment, usually with NaOH, accomplishing high effects in textile cleaning of genetic and added impurities. It results in hydrophilic, but also partially damaged cotton with high weight loss, decreased strength and degree of polymerization, what leads to lower fabric sewability. This traditionally procedure of scouring is ecologically and economically unfavorable, therefore in last few years new procedures of enzymatic scouring with pectinases were investigated. Compared with alkali scouring, enzymatic scouring (bioscouring) needs less energy, half of the amount of necessary water, and there is no pollution of waste water because enzymes are biodegradable and non toxic. In this paper raw cotton knitted fabric was scoured in three different ways – traditionally with alkali, and enzymatic with two pectinase - BioPrep 3000L (Novozymes), alkali one and Beisol PRO (Bezema), neutral one. It was prebleached, bleached optically bleached and softened. The influence of these treatments to cotton fabric properties such are hydrophility (drop test method), strength and degree of polymerization (DP), as well as fabric whiteness were compared. Damage of knitted fabric loops during sewing through two, three and four plies, which are closely connected with the values of sewing needle penetration force and dynamic tension of the sewing thread, were measured on new developed instrument which detects faults in samples of the knitted fabric by means of sensors.