Eco-friendly durable press finishing for silk and their characteristics

초록

Silk is one of the most desirable and luxurious textile materials because of its excellent properties such as handle or luster that distinguish them from other fibers. However, it has some minor textile performances such as crease recovery, dimensional stability, rubbing reisistance, photo-yellowing stability, etc. During the past three decades, graft copolymerization of the protein fibers with vinyl monomers was interested to increase their crease recovery property due to very low wet resiliency. Crease resistant finishes for silk could be separated roughly into two groups based on whether they contained formaldehyde or not. Trimethylol melamine, thiourea formaldehyde and hydroxymethyl methacrylamide are some examples of formaldehyde containing finishes. Non-formaldehyde agents include epoxides, glutaraldehyde, dibasic acid anhydrides, and polycarboxylic acids. 1,2,3,4-butanetetracarboxyic acid (BTCA) has low volatility, no odor, low skin irritation, as well as low oral and dermal toxicity in animal tests so that it will be the alternative of formaldehyde containing durable press (DP) finishing agents such as dimethyloldihydroxy ethylenurea (DMDHEU), the most popular finishing agent. Sodium hypophosphite (SHP) is widely used as an effective catalyst for the esterification reaction of silk with BTCA. But their commercial applications as catalyst in textile processing are limited because their reductive nature and the effluents containing phosphorus cause eutrophication in rivers and lakes. In this study, therefore, we examine the feasibility of nonphosphorous catalyst with citric acid (CA), propane-1,2,3-tricarboxylic acid (PTCA) and BTCA for the DP finishing of silk, including sodium acetate (SA), sodium propionate (SP) and sodium butyrate (SB) as the alternatives to SHP. In addition, we discuss their annexed effects as an alternative to the traditional mineral method by using tin phosphate and silicate for increasing the silk weight to compensate for the loss resulting from the degumming process.