Source: 佟昀 2.2 Comparison of sizing yarn reinforced ratio and shrinkage ratio The parameters of polyester sizing and pure cotton sizing yarn reinforcement rate and elongation reduction rate are shown in Table 2. It can be seen from Table 2 that the reinforcement rate of pure cotton warp yarn after sizing (59.0%) is much higher than that of polyester cotton sizing yarn (22.3%); the elongation rate of pure cotton sizing yarn (27.9%) It is also larger than the tensile reduction rate of polyester sizing yarn (23.1%). This shows that under the condition of almost the same sizing rate, the sizing of pure cotton yarn is mainly saturated (reinforced), and the polyester cotton yarn is mainly coated (wear resistant). The specific explanation is as follows: as the slurry penetrates into the inside of the yarn, it has an adhesion between the fibers, and after drying, it solidifies between the fibers, which increases the cohesion between the fibers and enhances the collective resistance of the fiber bundles to external forces. The ability to increase tensile tensile strength, however, this gelation also limits the possibility of the fibers slipping under each other under external force, the elongation at break is reduced, and the stronger the penetration of the slurry, the higher the enhancement rate. The greater the elongation rate. Therefore, the reinforcement rate and the elongation rate of the sizing yarn can be used as an important index for evaluating the penetration and coating of the slurry. Level Measurement,Liquid Level Measurement,Tank Level Measurement,Fluid Level Measurement Wuxi Winsun Automation Instrument Co., Ltd , https://www.jswxwinsun.com
Keywords: polyester/cotton yarn, cotton yarn, soak, coating, sizing performance, slurry
The development of shuttleless looms places higher demands on the strength, elongation, and especially wear resistance of sizing. In view of the electrostatic phenomenon of polyester-cotton fabrics and the high-density characteristics of poplin, the sizing hair removal rate and sizing quality are required to be high, and the sizing reinforcement, stretch and stretch, especially the wear-resisting and covered hairiness properties are all related to "soaking". The basic process of sizing with the coating, therefore, it is necessary to study the soaking and coating process of the sizing.
Generally, the sizing is adjusted by adjusting the size of the grouting force, the order of the pressure of the front and rear press rolls, the slurry formulation and its viscosity, the temperature, the pH value, and the warp coverage factor during sizing to change the ratio of the soaking and coating. , lightly covered, or "lightly soaked, heavily covered", or "soaked and covered and heavy" and other routes. In this paper, three comparative experiments were carried out to analyze and discuss the soaking and coating of polyester/cotton (65/35) and pure cotton warp sizing.
1 Experimental part The sizing and coating of sizing of polyester cotton and pure cotton warp yarns were analyzed by sizing slicing experiments on the microscope, sizing reinforced and deceleration experiments and desizing experiments.
1.1 Materials Polyester cotton fabric: JT / C (65 / 35) 13 tex × 13 tex, 547 / 10 cm × 370 / 10 cm; 160 cm anti-down feather. Cotton fabric: jc 14.6 tex × 14.6 tex, 524 roots / 10 cm × 283 roots / 10 cm; 160 cm poplin. Due to the limitations of the conditions, the fabric of the near-line density yarn was taken.
1.2 Instrument Hastelon slicer (Y172 type), biological microscope (E2oo type. 400 times), electro-optical analysis balance (TG.328B type), single yarn strength testing machine (YGO20 type).
1.3 Method 1.3.1 Visual observation of the sizing yarn slicing and integral weight quantification Cut the sizing yarn slice with a slicer and drop the dilute iodine liquid indicator and place it under the microscope to visually observe the pattern to the cardboard. On the top, the weighing measurement is separately cut.
1.3.2 Reinforcement and Deflection Rate of Sizing Yarn The sizing yarns of polyester-cotton and pure cotton falling shafts and the warp yarns not sizing at the machine were respectively subjected to the reinforcement and elongation-reduction tests on the single-strength strength testing machine.
1.3.3 Comparison of desizing time The above-mentioned full-width warp polyester cotton sample (6.53 g) and pure cotton sample (5.89 g) were placed in a beaker respectively, and the prepared desizing liquid (water: 750 mL, sulfuric acid: 21.9°Be, 12 mL), the beaker was placed on an electric furnace to heat and desizing, and the time (min) required for the refining of the polyester cotton and pure cotton sizing yarn was measured, and the experiment was continued to determine Desizing rate, etc.
2 Results and discussion 2.1 Visual observation and integral weight of sizing yarn slicing 2.1.1 Qualitative and visual observation of sizing slicing on microscope The qualitative observation of sizing slicing is shown in Figure 1. It can be seen from Figure 1 that the soaking of the pure cotton warp yarn by the slurry is much higher than that of the polyester cotton warp yarn.
2.1.2 Quantitative experiment of integral weight The permeation rate of polyester cotton and pure cotton sizing yarn is shown in Table 1. It can be seen from Table 1 that under the condition of nearly the same sizing rate, the slurry is more distributed inside the pure cotton yarn to form a sizing effect mainly for soaking, and for the polyester cotton yarn, the slurry mainly distributes the outer layer to form a coating sizing effect.
2.3 Comparison of desizing time The desizing time of the tested polyester cotton and cotton samples was 31 and 53 min respectively. For pure cotton sizing yarn, since the slurry penetrates into the inside of the yarn, the time required for desizing is long (53 min). For the polyester sizing yarn, the slurry is mainly coated on the outer surface of the yarn, so the desizing time is short (31 min). .
2.4 Influencing factors of penetration and coverage The polyester cotton yarn is easy to form coated sizing, and the main reason for the formation of soaking sizing of polyester/cotton yarn is the difference in hydrophilicity of textile materials.
2.4.1 Intrinsic determinants Water is the carrier of the slurry. If the textile material is hydrophilic, it must be saturated, and vice versa. This is mainly because the capillary effect of the material is the intrinsic power of the slurry soaking, and the premise of the capillary effect is the wettability of the material.
The pure moisture regain of pure cotton yarn is 8.5%, so it is easy to be wetted, the capillary effect is obvious, and the permeability is strong; polyester is hydrophobic fiber, its nominal moisture regain is only 0.4%, polyester, cotton (65/ 35) The nominal moisture regain of the yarn is 3.2%, and the hydrophilic cotton fiber only accounts for 35%. It is in a discontinuous distribution in the yarn body and is separated by the hydrophobic polyester fiber, so it is not easy to wet, capillary effect Very weak, poor penetration effect.
2.4.2 External auxiliary factors The increase of the grouting force and the hardness of the surface of the press roll will help to replace the air in the slurry and the yarn, which is beneficial to the wetting; increase the temperature of the slurry, reduce the viscosity of the slurry, and benefit the molecule. The Brownian diffusion movement is beneficial to soaking; reducing the coverage factor of the warp yarn during sizing, such as using a double-slot sizing machine, it will increase the gap between the warp yarns to increase the adsorption of the warp to the warp yarn, thus creating a good premise for soaking and coating. condition. The polyester-cotton warp yarn is mainly coated by sizing, and the pure cotton warp yarn can improve the woven property mainly by soaking the sizing, for the following reasons.
Hydrophobic polyester-cotton warp yarns have an enhancement rate of about 20% due to low permeability, and the data in Table 2 is 22.3%. The purpose of sizing is mainly to increase the wear resistance by coating, and at the same time, due to less impregnation, the binding force between the fibers is small, and the elongation at break of the polyester-cotton warp yarn can be kept high. In Table 2, the polyester sizing yarn is The elongation at break (31.6 mm) is nearly twice as high as that of pure cotton sizing (16.0 mm), so the yarn has high elastic recovery and can resist fatigue fracture caused by repeated action of the yarn due to small load. . The hydrophilic cotton warp yarn is strongly increased by more than 50% after being saturated with the slurry, and the data in Table 2 is 59%, thereby achieving the purpose of increasing wear resistance, resisting repeated impact, stretching, and especially friction of the yarn. The effect is to cause fatigue fracture of the yarn, and thus the reinforcement is only the ultimate purpose of the means rather than the sizing.
3 Conclusions 1) Polyester, cotton (65/35) warp yarns are easy to form sizing, pure cotton warp yarns are easy to form soaked sizing, and the moisture absorption of textile materials is the main factor determining the performance of slurry penetration or coating.
2) Polyester and cotton (65/35) warp yarns are mainly coated to enhance the abrasion resistance of the film, maintain elongation to increase the elastic recovery rate, and reduce the fatigue fracture of the sizing; the pure cotton warp yarn mainly increases the cohesion between the fibers by the osmosis. Increase sizing strength and collective abrasion resistance to reduce weaving breaks.
3) The slurry formulation should be considered according to the similar compatibility principle and the different characteristics of the soaking and coating of the polyester-cotton and pure cotton warp yarns. For the polyester-cotton warp yarns which are easy to form the sizing, only the pulp with high adhesion to polyester can be used. The sizing rate is increased to ensure the mechanical properties of the slurry film, for example, PVA, methyl acrylate (PMA), etc., which are actually used for grinding and preserving. For pure cotton warp yarns which are easy to form sizing, starch (including modified starch), PVA, CMC and other slurries have good adhesion to them, and the impregnation should be controlled to maintain elongation and increase the coating to improve wear resistance.
references:
[1] Yan Hequn, Dai Jiguang. Air jet loom principle and use [M]. Beijing: China Textile Press, 1996.266.
[2] (Day) Shen Tian wants to see Hui Yan. Warp sizing [M]. Liu Guanhong, translated. Beijing: Textile Industry Press, 1980.54, 117.
[3] Zhou Yongyuan. Textile pulp science [M]. Beijing: China Textile Press, 2OO4.292, 294.
Soaking and coating of pure cotton and polyester cotton sizing