Effect of Different Conditioning Methods on the Properties of Hosiery Yarn and Knitted Fabric

Transcription

1 Effect of Different Conditioning Methods on the Properties of Hosiery Yarn and Knitted Fabric Uzair Hussain, SameeIrshad, WardahAnam, HammadAbbasi, Faheem Ahmed, Abdul Jabbar National Textile University, Yarn Manufacturing, Faisalabad, Punjab PAKISTAN Correspondence to: Uzair Hussain ABSTRACT The research reports the results and investigations made on 20/1 cotton hosiery yarn and knitted fabric to evaluate the effect of different conditioning methods on the mechanical and comfort properties of yarn and fabric, namely, bursting strength, moisture management, thermal conductivity, air permeability, skewness, stiffness, and pilling. The fibers spun on a ring spinning system were investigated as yarn according to ASTM standards. From the results it is concluded that the knitted fabric made from machine conditioning has better mechanical and comfort properties than fabric made through unconditioned and room conditioned yarns. Keywords: yarn conditioning, knitted fabric, hosiery yarn conditioning, knitted fabric properties INTRODUCTION The project focused on the effect of room conditioning and vacuum conditioning of cotton hosiery yarn and compared the mechanical and comfort properties of yarn and knitted fabric. Cotton is a soft, staple fiber that grows around the seeds of the cotton plant. Today it is the most used textile fiber in the world. Its current market share is 56 percent for all fibers used for apparel and home furnishings and sold in the U.S [1]. Another contribution is attributed to nonwoven textiles and personal care items. It is generally recognized that most consumers prefer cotton personal care items to those containing synthetic fibers. World textile fiber consumption in 1998 was approximately 45 million tons. Of this total, cotton represented approximately 20 million tons [2]. The global cotton production and consumption figures will continue to rise to a further 2.0 million tonnes by the end of the season in major cultivation countries. World cotton production in season is projected at 25.5 million tonnes and world cotton mill use is expected to remain around 23.5 million tonnes [3].The earliest evidence of using cotton is from India, and the date assigned to this fabric is 3000 B.C. There were also excavations of cotton fabrics of comparable age in South America. Even though cotton fiber had been known already in South America, the large scale cotton cultivation in Northern America began in the 16th century with the arrival of colonists to southern parts of the United States. The largest rise in cotton production is connected with the invention of the saw-tooth cotton gin by Eli Whitneyin 1793[4].With this new technology, it was possible to produce more cotton fiber, which resulted in big changes in the spinning and weaving industry, especially in England.Cotton and viscose fibers are hygroscopic, that is, they have the ability to absorb moisture from the environment where they are kept [5]. Therefore, as the relative humidity of the environment increases, the amount of moisture absorbed by these fibers rises, which results in some changes in the physical properties of the yarns made of these fibers. On the other hand, moisture levels of yarns decrease due to modern machinery with high production speed. For example, cotton yarns contain 4-6 % moisture when they have been produced on a spinning machine [6]. The decreases in moisture levels of the yarns are likely to bring about some difficulties in the processing steps; also yarns with lower moisture content than the standard value result in monetary loss in sale. Therefore the moisture content of yarns must be increased to the standard levels so that their physical properties can be improved [7,8]. In the textile industry, applications such as conditioning, heat setting, relaxing, and shrinking are carried out in order to overcome these problems. The process carried out with the aim of increasing moisture content of the yarns is called conditioning. The conditioning process has been performed via various methods, such as conditioning in conditioning rooms, the circulation method of conditioning, and radio frequency conditioning. However, today, it is generally carried out on steaming machines which provide saturated moisture in a vacuum environment at a low temperature. In addition, some other processes such as heat setting and relaxation are performed on these steaming Journal of Engineered Fibers and Fabrics 12

2 machines. Heat setting and relaxation are also vacuum steaming processes which are carried out at high temperatures, and they increase the resistance of high twist yarns, multiply yarns, and synthetic filament yarns to untwisting and snarling problems which occur at their unwinding from packages. Therefore, all these processes are called vacuum steaming, and in this study the effects of vacuum steaming on the properties of 100 % cotton yarns were been examined [9]. There are two different types of vacuum steaming carried out with saturated steam in a vacuum environment: direct and indirect. In the direct system, the steam obtained in a separate tank is directly placed into the steaming chamber. In the indirect system, there is only one steaming chamber and the steam is obtained by heating the water bath with heaters at the bottom of the chamber. The temperature of the environment can be adjusted to the desired level by means of electrical heaters. Only a few studies were performed about the effects of vacuum steaming on the mechanical properties of yarns. Since the wet tenacity value of cotton yarn is higher than its dry tenacity value, these limited numbers of studies are concerned with cotton yarn, except for one study performed with 67 % PES - 33 % viscose yarns [10]. We chose 100 % cotton yarns for this study. MATERIALS AND METHODS The properties of cotton used for the production of yarn are given in Table I. Sr. No. TABLE I. Properties of Cotton Used. Parameters Units Values 1 Micronaire μg/inch Strength g/tex Length mm Uniformity % Short Fiber Index(SFI) % Elongation % Rd value b value Trash content Neps per gram /gram 210 Hosiery yarn was produced on the ring spinning system. The machinery details along with model and manufacturing company name of the spinning system from blow room to winding department are given in Table II. The chemicals and auxiliaries used for the scouring and bleaching of samples are given in Table III. Fabric processing equipment used is given in Table IV. Testing of samples was carried out using the equipment given in Table V. After producing the yarn, different conditioning methods were applied. Properties of those yarns are given in Table VI. Knitted fabric was produced on single jersey weft knitting machine. Courses per inch and wales per inch were also measured. The stitch length was also measured of each sample. specifications used are shown in Table VII. Specifications of fabric produced are given in Table VIII. Fabric was scoured and bleached in a single bath. Processing recipe and conditions are given in the Table IX. Sr. No. TABLE II. Yarn and Fabric Production Equipment. Make 1. Blow room Truetzschler, Rieter (B- 11, B-60) 2. CARD Crossroll (MK4- Tendom), Truetzschler (TC-7) 3. Draw Frame Breaker: Toyoda (DX-8) Finisher: Rieter (RSB D30) 4. Simplex Toyoda (FL 200) 5. Ring Frame Toyoda (RY 5) 6. Winding 21-C with Uster Quantum 7 Yarn Conditioning Xorella 8. AC Plant LUWA 9. Knitting Fukuhara Japan After processing, the samples were tested for bursting strength according to standard test method for bursting strength ASTM D using a bursting Journal of Engineered Fibers and Fabrics 13

3 strength tester. The liquid moisture management properties were evaluated by AATCC TM using moisture management tester M-290 SDL Atlas, UK. Pilling of the fabric was measured by using an ICI Pilling Tester BS-5811.Air permeability of the fabric was measured according to ASTM D (2008). The stiffness of the fabric was measured according to ASTM D The Skewness of the fabric was measured according to ASTM D (2006).Thermal conductivity of the samples was found using sweating guarded hotplate using standard test method for testing ISO , ASTM F1868, and GB Moisture content of the yarn was measured by moisture meter DELMHORST. TABLE III. List of Chemicals/Auxiliaries. Sr. No. Trade Name Description 1. NaOH Scouring Agent 2. H 2 O 2 Bleaching Agent 3. CiFA Wetting Agent 4. TANA WET Q Stabilizer 5. Agar Nutrient For Anti-bacterial Growth 6. Buffer Solution To adjust ph of Solution 7. Staphylococcus aureus Gram Positive Bacteria 8. Escherichia coli Gram Negative Bacteria TABLE IV. Processing Equipment. Sr. No. Make TABLE V. Testing Equipment. Sr. No. Equipment Purpose 1 Moisture Meter Moisture of Fabric 2 Shirley Stiffness Stiffness of Tester Fabric Air Permeability Tester Bursting Strength Tester Moisture Management Tester Sweating Guarded Hot Plate ICI Pilling Tester BS-5811 As per (ASTM D ) Measuring Stick, Flat Surface, Fabric Inspection Table (Optional) TABLE VI. Yarn Properties. Air Permeability of Fabric Bursting Strength of fabric Moisture Management of the Fabric To Determine Thermal Conductivity of Fabric Pilling of Fabric Skewness of Fabric Yarn Properties 1. Mini jet machine Japan 1992 Sample U% CVm IPI CLSP Un Journal of Engineered Fibers and Fabrics 14

4 TABLE VII. Specifications for Fabric Production. Sr. No. Description Value Unit 1 Gauge 20the mm 2 Cylinder Diameter 3 Feet 3 Needles Loop Length 5.98 mm 5 Speed 20 rpm 6 Yarn Speed m/min. TABLE VIII. Specifications of Fabric Produced. Uniformity percentage of fresh cone yarn is less than the room and machine conditioned yarn due to less moisture absorption in the fresh cone yarn. The more the moisture more will be the weight of the yarn; hence the more will be the U% of the yarn. In case of room conditioned yarn uneven moisture absorption occurs; hence more will be IPI values. In unconditioned yarn, the IPI values are comparatively less. The yarn test results are shown in Table VI. Moisture content of room conditioned yarn is greater than the machine conditioned and the unconditioned yarn, because of uniform moisture absorption during machine conditioning at the outer surface of the cone absorbs more moisture and the inner surface absorb less moisture. The more the moisture absorption, the more will be the moisture content that is why the moisture content of room conditioned yarn is greater than the unconditioned yarn. The results are shown in Figure 1. Sr. No. Courses per Inch Wales per Inch Stitch Length Un TABLE IX. Processing Recipe and Conditions. Sr. No. Description Value Unit 1 NaOH 5 g/l 2 Stabilizer 2 g/l 3 H 2 O 2 8 g/l 4 Wetting Agent 1 g/l 5 Temperature o C 6 Duration 1 Hr. RESULTS AND DISCUSSION CLSP of machine conditioned yarn is greater than the room conditioned and the unconditioned yarn, because of uniform moisture absorption during machine conditioning. The more the moisture mores, the greater will be the strength, hence more will be the CLSP value of the yarn. That is why the CLSP of room conditioned yarn is greater than the un conditioned yarn. FIGURE 1.Cone Moisture Content Test. Air permeability of machine conditioned fabric is greater than the room conditioned and the unconditioned fabric, because porosity of machine conditioned fabric increases due to the even shape of yarn and loop of the fabric. Whereas air permeability of room conditioned fabric is lower than the un conditioned fabric due to variable porosity in the room conditioned fabric, as the outer surface has more moisture and hence increases porosity whereas the inner surface has less moisture penetration due to lack of pressure; hence decreases porosity resulting in less air permeability in room conditioned fabric. The results are shown in Table X. Journal of Engineered Fibers and Fabrics 15

5 TABLE X. Air Permeability Test Results. Serial # Un Air Permeability (mm/sec) The test result comparisons are shown in Figure 2. FIGURE 2. Air permeability test result comparisons. Pilling of unconditioned fabric is greater than the room conditioned and the machine conditioned fabric, because of less moisture absorption in unconditioned fabric, which results in more hairiness. The more the moisture, the less will be the hairiness. Hence the pilling of the fabric will be greater. In the ICI pilling scale, higher values indicate less pilling and lower values mean high pilling. The ICI Pilling Tester results are shown in Table XI. TABLE XI. Pilling Test Results. FIGURE 3. Pilling Test Results. Bursting strength of machine conditioned fabric is greater than the room conditioned and the unconditioned fabric, because of high strength due to uniform moisture absorption during machine conditioning. The more the moisture, the more will be the strength; hence the more will be the bursting strength of the fabric. That is why bursting strength of room conditioned fabric is greater than the unconditioned fabric. The results are shown in Table XII. Sr. No. TABLE XII. Bursting Strength Results. Un Bursting Strength (kpa) The graphical representations of the results are shown in Figure 4. Sample Pilling Intensity Un 3 Moderate 4 Slight 4 Slight The graphical representation of the pilling test is shown in Figure 3. FIGURE 4.Comparison of Bursting Strength of Samples. Journal of Engineered Fibers and Fabrics 16

6 Thermal conductivity of room conditioned fabric is greater than the machine conditioned and the unconditioned fabric, because air permeability of room conditioned fabric decreases due to less porosity in the fabric. Whereas thermal conductivity of machine conditioned fabric is greater than the un conditioned fabric due to less porosity as compare to un conditioned fabric. The more the Rct(Thermal resistance) value, the more will be the insulation and the less will be the air permeability; hence the more will be thermal conductivity. Rct values of the samples are shown in Table XIII. TABLE XIII. Rct Values of the Samples. Sample Rct through unconditioned yarn also has uniform structure, but as hairiness is more, so moisture can easily move through the fabric. That is why it has good moisture management content, but lower than fabric made through machine conditioned yarn. Fabric made through room conditioned yarn has low moisture management content value, because of uneven distribution of moisture during conditioning. The outer layer received more moisture; hence fibers swelled; but inside the cone the moisture cannot evenly penetrate, so the yarn swelling is not uniform. That is why the fabric structure is not uniform and moisture cannot move through it. Hence it has low moisture management content values as compared to unconditioned and machine conditioned fabric. The results are shown in Figure 6. Un Graphical representations of the Rct values of the samples are shown in Figure 5. FIGURE 6. Moisture Management Test. conditioned fabric has low stiffness because of low snarling and twist setting due to even moisture distribution. In unconditioned fabric, the stiffness is more because of low moisture distribution. The results are shown in Table XIV. TABLE XIV. Stiffness Test Results. FIGURE 5. Thermal Conductivity Test Results. Sr. # Un Moisture Management Content of machine conditioned fabric is greater than the room conditioned and the unconditioned fabric due to the uniform structure of the knitted fabric and even moisture distribution. In machine conditioning due to high pressure and temperature the moisture is evenly penetrated in the cone and hence the swelling of the fibers is uniform. That is why the fabric made from machine conditioning yarns has uniform structure and moisture can easily move through it. Fabric made Stiffness The graphical representation of the results is shown in Figure 7. Journal of Engineered Fibers and Fabrics 17

7 FIGURE 7. Stiffness Test Results. Skew is a fabric condition resulting when filling yarns or knitted courses are angularly displaced from a line perpendicular to the edge or side of the fabric. Skewness of the machine conditioned fabric is less as compared to unconditioned and room conditioned fabric, because of twist setting in the machine conditioned fabric. In machine conditioning the moisture is evenly distributed, so the swelling of the fibers occurs uniformly and hence snarling decreases which results in less skewness. In room conditioning the outer layer of the cone received more moisture, but the inner part cannot get the same moisture, so uneven moisture distribution occurs which results in uneven yarn strength and hence uneven fabric structure, which causes the yarn more swelled at one place and less at another. When knitted fabric is made, the loop formation is not uniform because of non uniformity in the yarn. So due to the non uniform structure of the fabric the skewness is greater as twist setting occurs at some places but at most of the places snarling occurs. The Results are shown in Table XV. TABLE XV. Skewness Results. Sr. # Un M/C Skewness (degree) The graphical representation of the results is shown in Figure 8. FIGURE 8. Skewness Test Comparison. CONCLUSION conditioned yarn will have higher moisture content value due to more absorption of moisture on the cone surface. More uniform moisture absorption will have more uniformity in yarn shape; more will be the porosity of the fabric and hence more will be the value of Air Permeability. Uneven distribution of moisture lowers the value of AP (Air permeability). The more uniform the moisture is absorbed, the more will be the CLSP of the yarn. That is the reason unconditioned fabric has low bursting strength. Less moisture absorption results in more hairiness; hence the more will be the pilling of the fabric. and conditioned fabric have almost the same effect for pilling. The rise in the value of Rct (Thermal resistance) results in increased insulation, which decreases the value of AP (air permeability) hence thermal conductivity increases. conditioning increases the thermal resistance. conditioning ensures the uniform shape of yarn and uniformity of the structure of knitted fabric; hence moisture management content of machine conditioned fabric is greater than the room conditioned and the unconditioned fabric. Even moisture distribution results in twist setting of the yarn, which reduces snarling effect. So machine conditioned fabric has low stiffness because of low snarling and twist setting. Twist setting of yarn reduces the skewness of the fabric made from it. conditioned fabric has high skewness, because of non uniform absorption of moisture. conditioned fabric has low skewness. Journal of Engineered Fibers and Fabrics 18

8 REFERENCES [1] Cotton for Nonwovens : A Technical Guide, Cotton Incorporated (Online) Available 5 June 2013] [2] Lawrence H. Shaw; Cotton s Importance in the Textile Industry", Symposium, Lima, Peru, May 12, 1998 [3] Razi Syed Global cotton output, consumption figures continue to rise October 2013, (Online) Available: ge=2013%5c10%5c20%5cstory_ _pg5_16 [Accessed 2 Nov 2013] [4] Kadolph, S.J., Langfold, A.J.: Textiles, 8th edition, Prentice-Hall, [5] Adanur S., 1995, Wellington Sears Handbook of Industrial Textiles, Technomic Publishing Co. Inc. Lancaster.-Basel., pp: 589. [6] Özdemir O. and Dayık M., 2011, Conditioning of Cotton Yarns and Studies Performed in This Field, Textile Marathon, Vol: 4 (July- August), pp: [7] Özdemir Ö. and Şardağ, S., 2004, Yarn Conditioning and New Methods, Tekstil&Teknik, June, pp: [8] Özdemir Ö. and Şardağ S., 2005, Vacuum Steaming Processes Applied to Yarns, Its Application Fields and Improvements, Journal of Engineering Sciences, Pamukkale University Engineering College, Vol.11, No. 2, pp: [9] Şardağ S., 2008, A Study About Vacuum Steaming Processes of Yarns and Their Effects on Yarn Properties, Doctorate Thesis, Uludağ University, Bursa,pp: 1, 95, , , [10] Şardağ S., Özdemir Ö. and Kara I., 2003, The Effects of Heat Setting on The Properties of Polyester/ Viscose Blended Yarns, Fibres& Textiles in EasternEurope, Vol. 15, No. 4 (63), pp: AUTHORS ADDRESSES Uzair Hussain SameeIrshad WardahAnam HammadAbbasi Faheem Ahmed Abdul Jabbar National Textile University Yarn Manufacturing Shiekhupura Road Faisalabad, Punjab PAKISTAN Journal of Engineered Fibers and Fabrics 19