At present, ordinary polyester low- elastic yarns and network filaments are far from satisfying market needs due to their single varieties. How to use the existing texturing machine equipment to develop and produce new products that are marketable. It has great practical significance and economic benefits. Polyester shrinkage network filaments can be obtained by a combination of air entanglement deformation, uneven pulling and different physical properties of chemical fiber precursors. The product has the fluffy feel and good elasticity of conventional textured yarns. There are also many intersection points between DTY and POY. It is a new filament variety that provides weaving of various fabrics. It is of great significance for the development of novel textiles, adapting to market supply and demand, improving people's clothing and improving economic efficiency.
In this paper, through the relationship between the polyester shrinkage network and the product style, the mature machine process conditions are explored. The results show that it is feasible to produce polyester shrink-resistant network wire after simple modification on ordinary texturing machine.
1.1 Raw material performance and origin
PET is a slice produced by Tianjin Petrochemical Corporation. The properties of raw materials are shown in Table 1.
1.2 Product specifications (see Table 2)
1.3 Test equipment
Front spinning: slightly
Bombing: Modified FK6-600 drafting false twisting machine
1.4 Test conditions
Coupling device: It has the function of wire deformation deformation and is installed in the wire path of each spindle before the three rollers.
1.5 Production process
The original yarn POY is balanced and placed on the creel → wire drawing tube → wire cutter → yarn displacement → one roller → I heater → cooling plate → false twist device → yarn sensor → guide wire wheel → yarn displacement → two roller → I heater → nozzle → yarn displacement → three roller → yarn sensor → oil tank → winding into DTY cylinder.
Second wire (POY) wire routing:
The original yarn POY is balanced and placed on the creel → the wire drawing tube → the yarn displacement → the second roller is combined with the first DTY wire.
1.6 Main process parameters
Heater temperature: 200 °C ± 1; II heater temperature: 135 ° C soil 1: D / Y: 2, 12: DR: 1.68 ~ 1.69; OF2: - 3.64 ~ - 5.41; OF3: - 5.41 ~ - 7.14; :0.6mpa.
Results and discussion
2.1 Analysis of processing principle
Polyester shrinkage network wire, in essence, is a joint of DTY and POY. The collocation method we use, that is, the two wires enter the symmetry chamber together. Since the DTY is drawn through the roller between the roller and the roller, the speed is always under the control, and then the wire chamber can be properly treated under the action of the airflow. Open, the tension is greater. The second POY is incorporated from the second roller and enters the second heating box at the same time as the first wire. The feeding of the two wires has been fixed, since the POY is not fully drawn. The elongation is greater than DTY, so that between adjacent intersection points, POY floats significantly on the DTY surface. The floating yarn effect is produced. At this point, the two wires are periodically entangled and formed with the open DTY wire as the axis, and the POY is blown open to give a fishtail shape. The effect of different temperatures of the second heater on the product specifications is shown in Table 3.
2.2 Relationship between shaping temperature and elongation (see Figure 1)
As can be seen from Figure 1, the second heater setting temperature below or above 135 °C has a very high effect on the elongation of the finished product. The PET change activity starts at a glass transition temperature of 67-69 ° C or higher. Since the macromolecular segment is long enough to pass through the crystal region, the fiber has a certain elastic recovery property at 135 ° C. POY and DTY open the DTY under the action of air compression, and the stretched DTY and POY are evenly entangled due to the agitation of the airflow in the nozzle. When subjected to stress-induced orientation, the macromolecular chain is turned from a entangled state to a more regular alignment with a direction parallel to the stress direction. Under good shaping conditions, the molecules are arranged closely. Because the elastic deformation changes faster than the plastic deformation. The cooling rate before shaping is the key. The faster the cooling, the more the orientation is, which is more favorable for the double-stretching orientation.
2.3 Effect of setting temperature on boiling water shrinkage
For the production of DTY with polyester POY as the original yarn, the setting temperature is one of the main factors affecting the heat shrinkage performance of the fiber. The experimental results of the effect of setting temperature on fiber boiling water shrinkage are shown in Fig. 2.
It can be seen from Fig. 2 that the setting temperature is between 120 ° C and 135 ° C, which increases with the setting temperature. The boiling water shrinkage rate rises slowly; the setting temperature is above 135 °C. As the setting temperature increases, the boiling water shrinkage rate decreases, indicating that the boiling water shrinkage and the setting temperature are linear; the shape below 135 °C is set to low temperature setting, and in the shaping process, the thread The interior tends to relax, and the lower the setting temperature, the greater the stress frozen in the fiber and the greater the boiling water shrinkage.
Above 135 ° C, much higher than the glass transition temperature of the fiber. The segment has been fully moved, and the high-temperature setting process is accompanied by the fiber crystallization process; the stress inside the wire is small, and the boiling water shrinkage rate is correspondingly small.
2.4 Effect of setting temperature on dry heat shrinkage rate (see Figure 3)
Experiments show that there is a low value around 160"C, which is due to the increase of the amorphous temperature, and the amorphous content decreases. The grain size increases, the number of crystal grains decreases, the amorphous volume around a single crystal increases, and the strain of silk increases. Therefore, after the shaping, that is, after the heat treatment, the shrinkage effect of dry hot air is reduced. Especially the morphological structure of POY and DTY double strands is different from ordinary network filaments, and the shrinkage rate is exactly the same. Differences give fabrics a unique style of fabric.
(1) It is preferable to select a processing speed of 300 to 350 m/min for the shaped shrinkage yarn. The structure is stable, the output is doubled, the quality is guaranteed, and the operation is easy.
(2) Prepare a special-shaped shrinkage fiber with a shrinkage ratio of 20 to 35%, and the setting temperature is preferably 135 ° C ± 1.
(3) Shrinkage and mechanical properties of the profiled shrinkage yarn. Take care of both, the elongation should be controlled at 20%.
(4) The crimp reduction ratio can be controlled between 5 and 8%.
(5) shaped shrinkable fibers, differential shrinkage to fabrics bring irregularities bulkiness, since fine and coarse fiber portions coexist, the difference between the wires of the degree of orientation; difference of dye adsorption, to produce shades of white; yield silk yarn between the length difference, Enhances the texture of the fabric and eliminates the waxy surface. It is currently a more advanced blending method.