Indian Journal of Fibre & Textile Research Vol. 23, March 1998, pp.44-48 Effect of various softeners on the performance of polyester-viscose air-jet spun yam fabrics ring and. I C Sharma, D P Chattopadhyay, K N Chatterjee, A Mukhopadhyay & A Kumar The Technological Institute of Textile and Sciences, Bhiwani 127021, India Received 4 March 1996; revised received and accepted 24 December 1996 The effects of various softeners, viz. cellulase enzyme, caustic soda, a combination of cellulase enzyme and caustic soda, and non-ionic softener on the performance of twill fabrics made from polyester-viscose ring and air-jet spun yarns have been investigated in terms of flexural rigidity, tensile strength and crease recovery. The influence of pick density on the above properties has also been studied. It is observed that crease recovery and flexural rigidity improve considerably for the fabrics treated with cellulase enzyme followed by caustic soda, reasonably for the fabrics treated individually with the cellulase enzyme and caustic soda and marginally for the fabrics treated with non-ionic softener. On the other hand, the fabric strength is affected in all the above cases to a small extent. The effect of chemical treatment is greater on the mechanical properties of air-jet spun yarn fabrics. With varying pick del}sity,the response of air-jet yarn fabrics to chemical agents is different than that of ring yarn fabrics. Improvement in crease recovery and flexural rigidity is greater for air-jet yarn fabrics at the cost of reduced tensile strength. Keywords: Air-jet spun yarn, Crease recovery, Flexural rigidity, Non-ionic softener, Ring-spun yarn, Tensile strength 1 Introduction Fabrics made from air-jet spun yam have higher flexural rigidity than those made from ring-spun yam. This is due to the interlocking of wrapper fibre at yam cross-over which restricts yam movement during fabric deformation, resulting in a stiff fabric. The formation of wrapper fibre under high tension in air-jet spinning results in a high component force directed towards the yam core. This high internal pressure severly restricts the fibre movement during bending, preventing fibre strain reliep. Air-jet spun yam fabrics are less prone to pilling than ring yam fabrics. In the present work, an attempt has been made to reduce the rigidity of air-jet spun yam fabrics by the application of enzyme (cellulase), alkali and a commercial non-ionic softener. Cellulase enzymes are being widely used today for eco-friendly biopolishing and softening of cellulosic garments. They are very specific in their action and act only on the cellulosic portion in cellulosic blended fabrics. Alkali, on the other hand, attacks the polyester component as cellulose is rather resistant to mild alkaline attack. Therefore, both the treatments have been applied separately and in tandem and the effects of these treatments have been compared with those of the commercial softener. 2 Materials and Methods 2.1 Materials Six twill weave fabrics were made using polyester-viscose (65:35) ring-spun yams as warp and polyester-viscose (65:35) ring/air-jet spun yams as weft with different pick densities (18, 20 and 22). The properties of ring and air-jet spun yams are given in Table 1. The fabrics were given different softening treatments (Table 2). 2.2 Methods The fabrics were conditioned for 24h and all the tests were carried out in an atmosphere' of 20±2 C and 65±2% RH as per the standard procedures laid down in the B.S. Handbook, ASTM, etc.
SHARMA et a/.: RING AND AIR-JET SPUN YARN FABRlCS 45 2.2.1 Fabric Mass and Fabric Thickness Fabric area density was determined as detailed in BS : 2491 (1971). Thickness was measured by the R & B cloth thickness tester of James H. Heal & Co. Ltd, Halifax, England, at a pressure foot of 20 g/cm2 2.2.2 Crease Recovery Crease recovery was determined as detailed in IS:4681-1968 using the Shirley crease recovery tester. 2.2.3 Flexural Rigidity Stiffness was determined using the Shirley stiffness tester. Fabrics were tested according to ASlM 0: 1388-557. 2.2.4 Tensile Strength The tensile strength was measured Table I~roperties of polyester-viscose ring and air-jet spun yams Parameter 7.25 3.71 65/35 40/2 3139 012.54 MJSyarn 0.64 16.916 Ring 15.2 065/35 21.55 ]4.36 3810 40/2 0.81 1.67 9.1yarn Thin (-50%) on Goodbrand's tensile strength tester and expressed in g/tex. Fabrics were tested according to BS:2576 1967. 3 Results and Discussion The physical and mechanical properties of airjet spun yarn fabrics and ring-spun yam fabrics before and after the softening treatments are given in Tables 3-5. 3.1 Fabric Thickness and Fabric Weight It is clear from Table 3 that the thickness of the enzyme- treated fabric is less than that of the grey fabric as the enzyme treatment leads to removal of very fine surface cellulosic fibres.a reasonable decrease in the thickness of the fabric treated with caustic soda has been found which may be due to the dissolution of surface fibres. However, the fabric treated with cellulase enzyme followed by NaOH shows the lowest thickness. In fabric treated with non-ionic softener (Auxisoftener NI), the extent of decrease is much lower as compared to that in other treatments. The increase in pick density with ring and air-jet spun yarns shows no definite trend of decrease in thickness. It is also observed from Table 3 that the weight of all the fabrics decreases to marginal exient due to the softening treatments. Fabrics treated with cellulase enzyme followed by NaOH show higher reduction in weight in comparison to fabrics subjected to other treatments. However, weight is not much affected with non-ionic softener Cellulase enzyme Cellulase enzyme, 1.5% on the weight of viscose Temperature,50-55OC Duration, 60 min ph,44.5 Washed with dilute N~C03 and dried Table 2-Various softening treatments given to grey fabrics NaCH Cellulase enzyme Non-ionic softener (Auxisoftener & Nl-a polyglycolic long-chain NaOH compound) NaOH(2%) Temperature, R.T. Duration, 20 min Washed, neutralised and dried Cellulase enzyme, 1.5% on the weight of viscose Temperature,50-55OC Duration, 60 min L:M=40:] ph, 44.5 Washed with N~C03' dried and then treated with 2% NaOH under the following conditions: Temperature, R.T. Duration, 20 min Washed and neutralised Auxisoftener. 4 gil Acetic acid, I gil Temperature, 40450C Duration, 30 min
46 INDIAN J. FIBRE TEXT. RES., MARCH 1998 201.07 201.85 Table 202.15 207.89 213.35 207.07 212.98 203.31 210.35 (-0.69) 214.87 215.57 (-1.78) 203.86 Picks/em (-1.14) (-0.42) (-38.3) 207.15 209.95 210.92 0.369 0.382 216.21 0.370 (-1.8) (-0.57) 207.95 206.79 0.372 214.01 212.21 0.367 (-I. (-41.4) (-1.44) (-0.61) (-36.3) (-38.1) (-0.60) 0.365 0.356 201.77 200.26 BCDEABCDE18 0.391 0.361 200.10 (-1.60) 209.45 (-1.69» (-41.1) 214.07 0.380 0.357 (-0.72) (-1.55) (-1.02) (-37.8) 0.360 0.612 22 214.55 213.09 (-0.76) 0.398 0.401 (-37.4) (-0.45) (-37.6) 0.378 202.62 0.411 0.614 0.601 (-33.5) 0.407 0.607 208.45 0.352 0.355 0.603 (-33.4) (-1.17) (-41.2) (-33.0) (-33.3) (-33.7) 0.608 0.408 (-32.9) 0.405 199.64 18 3-Effect A (-39.4) (-29.9) (-39.5) (-39.7) (-39.9) of Weight, various softening glm2 treatments Thickness, on weight rom and thickness of ring and air-jet spun yam fabrics A-Fabric C-Fabric and The E---Control values [Warptreated inand parentheses fabric. weft with blend cellulase indicate composition, enzyme; % change & B-Fabric 65:35 2% duenaoh; PN; to treatment treated Warp D-Fabric and with weft 2% treated respect count,40/2 NaOH; with to control Auxisoftener tex; and fabric. Weave, NI; twill] treatment as no surface dissolution takes place in this case. 3.2 Crease Recovery It is observed from Table 4 that the crease recovery improves substantially after all types of finishing treatments. Treatment with cellulase enzyme followed by caustic soda gives the best result. The effect of Auxisoftener NI on crease recovery is minimum while that of caustic soda and cellulase enzyme (when treated separately) is moderate. It is interesting to note that although the decrease in thickness is maximum in case of fabric treated with cellulase enzyme followed by caustic soda, still the fabric exhibits maximum crease recovery value. The above phenomenon could be explained from the decrease in fabric weight per unit area. Higher reduction in fabric weight will result in more open fabric which may assist fibre strain relief in yam during creasing and hence better recovery. It is further observed from Table 4 that for the same pick density, th~ air-jet spun yam fabrics show substantial improvement in crease recovery compared to ring-spun yam fabrics. This may be due to the partial dissolution of wrapper fibres, which leads to greater ease of fibre movement as yam gets flatten at creasing area, resulting in development of less stress and strain during creasing. For both ring and air-jet spun yam fabrics treated with cellulase enzyme followed by caustic soda, improvement in crease recovery increases with the increase in pick density. A similar trend is also observed when the fabrics are treated with the above softeners separately.. For fabrics treated with Auxisoftener, no define trend is observed. 3.3 Flexural Rigidity It may be seen from Table 4 that cellulase enzyme treated fabrics exhibit considerably lower value of flexural rigidity. This is due to the hydrolysis of 1-4 glucosidic bond of the cellulose molecules, which, in turn, leads to decrease in modulus of fibre constituents in fabric. Increase in inter-yam spacing in the fabric due to removal of fine fibrils from surface may also contribute to the above phenomenon. Fabrics treated with NaOH show lower rigidity than the control fabrics. Also, there is a considerable decrease in flexural rigidity of fabrics when treated with cellulase enzyme followed by caustic soda. The above phenomenon is due to the morphogical change in the constituent fibre which decreases the modulus of fibre and,in turn, decreases the fabric bending modulus. The extent of improvement in flexural rigidity is higher for air-jet spun yam fabric. This phenomenon can be explained through the
SHARMA et af.: RING AND AIR-JET SPUN YARN FABRICS 47 ric. Fabric Table 4--Effect of various softening treatments on the total crease recovery and total flexural rigidity of ring and air-jet spun yarn fabrics Fabric (1.01 (2.15) (+11.2) (5.05) (9.64) (I.I6) (+11.7) (10.12) 1.91 3.17234.8 (5.76) 3.42247.3 1.73 4.00215.9 3.91 4.42 3.51 2.01 Weft 4.36 2.08 1.99 3.83 3.38 Warp CDEABCDE 238.3 218.3 1.95 1.89 1.86 (6.94) 230.8 227.0 (-18.6) (-65.5) (-66.5) (4.71) (3.36) (3.85) (6.53) (1.66) 216.4 202.2 1.72 1.54 (4.35) 1.71 1.78 1.82 1.41 (+1.6) 254.5 232.9 242.6 221.7 1.83 1.98 1.94 (5.32) (4.78) (3.47) 2.56 (+6.7) (+1.1) (-69.3) (7.1 (+9.3) (6.45) (4.8) (6.73) 231.0 218.8 221.9 206.7 (-20.7) 1.14 (-68.1) 1.76 1.74 1.44 1.42 1.59 (8.86) 1.75 1.58 1.50 (4.82) 1.79 1.67 1.61 I.71 (-26.0) (+2.2) (2.71) (+6.0) 237.4 217.5 212.2 1.85 1.84 240.7 2.34 (6.09) (-24.0) (-71.6) 1.20 (3.52) (-23.0) (5.37) (1.09) 1.52 3.08 (+9.4) (-70.3) 1.64 2.67 249.4 1.97 (5.78) 3.12 (+8.7) (3.67) (+8.4) 3.74 219.2 1.43 1.51 1.80 (9.04) 1.63 1.31 237.8 224.5 1.88 1.92 (1.24) (3.2) 2.43 (6.3) (5.5) (+2.3) (5.0) (-1.2) 2.78 (3.8) (+3.7) (+8.0) (-6.5) (-1.3) (1.2) (-2.4) (+7.9) (-1.7) (3.5) 1.03 1.30 238.5 225.8 227.8 1.84 1.95 1.77 1.55 1.70 1.79 AI) A(-67.9) (-21.0) (-20.9) (-66.7) (-23.2) (-69.8) BCDE Crease recovery, deg Flexural Tensile rigidity,mg-cm2 strength, g/tex (+7.2) 2.86 (-19.1) 233.2 Table 5--Effect of various softening treatments on the tensile strength of ring and air-jet spun yarn fabrics dissolution of wrapper fibre in case of air-jet yarn fabric as with the removal of sheath fibre, core fibres are able to flatten easily while bending takes place, leading to less flexural rigidity. It may also be noted that the percentage improvement gradually increases as the pick density increases for both types of fabric. However, the air-jet yarn fabric is more responsive to finishing process than the ring-yarn fabric. 3.4 Tensile Strength It is clear from Table 5 that there is a marginal loss in strength due to all types of softening treatments. However, the maximum drop in strength is observed for fabrics treated with cellulase enzyme followed by NaOH, and minimum for fabrics treated with Auxisoftener NI. The above phenomenon could be explained from the morphological change in the fibre constituents in fabric and fabric weight. Fabrics treated separately with NaOH and cellulase enzyme show moderate drop in strength as expected. All air-jet spun yarn fabrics, except the one treated with Auxisoftener NI, show higher loss in weft-way tensile strength as compared to ring-spun yarn fabrics at the same pick density. The above phenomenon is expected as the dissolution of wrapper fibres reduces inter-fibre friction in the yarn, which, in turn, reduces the fabric strength. However, warp-way tensile strength does not follow any particular trend with different types of softener. Again, with increase in pick density, the
48 INDIAN 1. FIBRE TEXT. RES., MARCH 1998 tensile strength of the fabrics does not show any definite tend for different softening treatments. 4 Conclusions Thickness, weight, flexural rigidity and strength values of fabrics made from ring and air-jet spun yams decrease by all the softening treatments studied. Crease recovery improves substantially with the application of different softening treatments, the maximum effect being observed with cellulase enzyme followed by caustic soda treatment and the least with non-ionic softener (Auxisoftener NI).Cellulase enzyme and caustic soda treatments when applied separately give moderate effect.the extent of influence on all the above properties is greater for air-jet spun yarn fabric as compared to ring-spun yam fabric. Acknowledgement The authors are grateful to Prof. R C D Kaushik, Director, TIT&S, Bhiwani, for providing facilities to carry out this work. They are also grateful to the management and staff of Bhiwani Textile Mills for the preparation of fabric samples. Reference 1 Vohs K M, Barker R L & Mohamed M H, in Objective measurement: Applications to product design and process control, edited by S Kawabata, R Postle and M Niwa (Text. Mach. Soc, Japan), 1985, 121.