Effect of Hot Water Processing on Dyeing and Mechanical Properties of Cottons Treated with Liquid Ammonia and Sodium Hydroxide

Abstract

NH3 and NaOH/NH3 treated cotton fabrics are processed with hot water at 100 and 130°C, and excellent shrink resistance is obtained with the processing. The crystallite form is transformed from cellulose III to cellulose I. Crystallinity decreased by the NH3 treatment increases a little after hot water processing and washing shrinkage is considerably controlled. Although the dyeing rate decreases with the NH 3 treatment, it increases a little with subsequent hot water processing. In contrast, equilibrium dye uptake decreases with the processing. The mechanical properties of the processed fabrics are evaluated by means of KES shear behavior ( G, 2 HG ) and bending hysteresis ( B, 2HB ). G and 2HG decreased by NH 3 and NaOH/NH 3 show almost no change after hot water processing, while B and 2HB, especially the latter, decrease considerably with the hot water processing after treatment with NH 3 and NaOH/NH 3 . Liquid ammonia has been used to improve the hand of the cotton fabric [1][2][3][4][5][6][8][9][10][11]. Previously, we reported that liquid ammonia treatment induces a change in the fine structure of cotton fibers and influences dyeing [12] and Ks mechanical properties [ 13,14]. Furthermore, we investigated the effect of two-step processes such as NaOH/NH3 and NH3/NaOH. NaOH/NH3 treatment was much more effective at improving the soft hand of the fabric compared with NH3 alone [13,14]. On the other hand, NH3/NaOH improved dyeing properties, though the hand was inferior to the NH3 and NaOH/NH3 treatments [14].In this study, NH3 and NaOH/NH3 treated cotton fabrics are subsequently processed with hot water at 100 and 130°C. We then measure dyeing and mechanical properties and evaluate the effect of hot water on functional properties by means of KES measurements. ExperimentalDesized, scoured cotton fabric was mercerized under tension and subsequently treated for 2 seconds with NH3 at free dimensions using a practical range (Nisshinbo Co. Ltd.) [12][13][14]. The treated fabric was then processed with hot water at 100 and I30°C in a relaxed state using a Texam Minicolor laboratory-type high pressure dyeing machine (Texam Co., Ltd., Japan).The pretreated fabric was washed twenty times in a home electric washing machine according to the JIS L 1042 G method. Shrinkage was obtained by an average of five measurements. Dry crease angle was measured with a Monsanto crease angle tester in both warp and fill directions ten times each to get an average. Moisture regain and water absorption were measured according to the following procedure: The fabric was impregnated in distilled water for 24 hours and then centrifuged for 20 minutes at 3000 rpm ( W, ). Next, the

Ammonia‐gas and liquid ammonia treatments of silk fabric

“…We expected that an increase of the equilibrium dye uptake of the silk fabric with the acid dyes would correspond to an increase in the active amino group of the silk fabric available for dyeing because of the relaxation of the amorphous region by the treatments. In a previous study,2, 10, 11 we reported that liquid ammonia treatment of the cottons induced a considerable decreases in crystallinity, nevertheless the apparent dyeing rate with Direct Blue 1 was controlled a little compared with that of the untreated fabric. However, the equilibrium dye uptake of the liquid ammonia treated cottons increased more than the untreated.…”

“…Liquid ammonia treatment has been practically done in textile finishing since 20 years ago, and is been carried out as a pretreatment of the shape stability and for improving the soft hand of cotton fabric. The liquid ammonia treatment of cottons caused a decrease of the apparent dyeing rate comparing with the mercerization despite a considerable decrease in the crystallinity 1–3. The liquid ammonia treatment is not always effective in increasing the dyeing rate not only for the cellulosic fiber,2, 4, 5 but also for the nylon 6 fiber.…”

“…The liquid ammonia treatment of cottons caused a decrease of the apparent dyeing rate comparing with the mercerization despite a considerable decrease in the crystallinity 1–3. The liquid ammonia treatment is not always effective in increasing the dyeing rate not only for the cellulosic fiber,2, 4, 5 but also for the nylon 6 fiber. The liquid ammonia treatment brought about a partial transition of the crystallite structure of nylon 6 fiber from the γ‐ to the α‐form, and improved the soft hand and dyeing properties of the nylon 6 fabric 6.…”

Knit Fabric Mercerisation through the Use of High-Concentration NaOH in a Scouring and Bleaching Bath using an Exhaustion Method

“…Mercerisation at high temperature is now a well-established method [13]. e penetration of caustic soda into the bre structure is more rapid [14], which ensures more uniform treatment but less swelling [8]. is in turn enhances lustre without a ecting the strength of the bre.…”

Ozone-Gas Treatment of Wool and Silk Fabrics

“…Liquid ammonia treatment has already been practically processed for cotton fabric [1][2][3][4][5]. We, before now, studied the effect of the treatment on fine structure of the cellulosic fibers in relation to the dyeing and KES mechanical properties [4,5]. Recently, ammonia-gas treatment of the cellulosic, wool, and silk fabrics was done [6][7][8][9].…”