Spunbonding machine - a method of reforming airflow stretching equipment

The fiber drawing of the spunbonded nonwoven fabric is carried out by using a gas stream, which is a unique stretching method of the spunbonding method different from the chemical fiber filament, and is a spunbonded heart. At present, there are four ways of airflow stretching in China, namely 1-tube stretching, such as polyester spunbond production line, STP type production line and MODERN type production line; 2 narrow slit type positive pressure stretching, such as NWT production line and Shenyang Center, 606 and Shanghai Hefei Institute's early production line; 3 long slit type negative pressure production lines, such as the domestic production line of the Reifen type and the recent Wenzhou Changlong company; 4 long slit positive pressure production lines, such as NKK, Nordson Companies and Hongda Research Institute. These production methods can produce spunbond fabrics normally, but they have different effects on the stretching effect and the uniformity of the fabric.
Excellent airflow stretching equipment should be able to achieve the following functions: 1 with high efficiency to adjust the stretching speed; 2 can change according to the production process and variety; 3 energy saving; 4 equipment is simple and easy to control; Evenly laid out. Let's take a look at our four current airflow stretching devices.
The first is tubular stretching, which is the earliest stretching of the spunbonding method. It originated from the German company Luqi. At present, there are more than 30 production lines using this method in China, and dozens of monofilaments are grouped together. Stretched with compressed air in a Ф10 mm stainless steel tube. A 3.2mm wide device consists of dozens of small tubes. The advantage of this method is that the fiber can reach a speed of 5000m/min, but the disadvantages are many. The structure of the equipment is complicated. Stainless steel pipe, there must be a large number of metering pumps, spinnerets, melt valves, compressed air valves and a large number of under-roller rocking equipment, and the energy consumption is also high, the position of the drafter is fixed, can not follow the process And the change of the variety changes, the fiber is not evenly distributed. At present, the United States, Japan, and Germany have eliminated this tubular stretching method, and only the Italian STP company and ORV company are still in use. All relevant spunbond factories in China should also consider reforming this outdated old method, transforming their own stretching equipment, and improving the quality of spunbonded fabrics.
Then there is a small slit stretching method, which starts in Italy N. W. Company T, which was later copied by many companies in China, in this way, a plurality of fibers which are obliquely arranged in a line of spinnerets are drawn into a small slit drafter for stretching, and the fibers are laid by a rocking roll. The equipment structure is also more complicated, the metering pump is more, the melt valve is more, the spinneret is more, the air pressure valve is more, the rocking roller is more, the fiber is unevenly formed, and the advantage is that the lateral strength of the cloth is better, and the width of the cloth is wider. It can be adjusted to a narrow direction. In recent years, China has basically stopped manufacturing such equipment.
Long slit type negative pressure stretching, China began to use the introduction of Lefite equipment. In recent years, many places in China have produced similar equipment according to this principle, which is characterized by using only one long strip of spinneret. One or several metering pumps cover the drafter on the netting machine and draw air under the netting machine for stretching. The main advantage of this form is that there is only one spinneret, and the spinning box is much simpler and does not require much. The drafting pipe eliminates the rocking and laying method, so the uniformity of the cloth becomes better, and the power consumption is the lowest. The disadvantage is that the stretching speed is relatively low, the height cannot be increased, and the transverse tensile force of the spunbonded cloth is low, and The equipment is all fixed on the steel platform and cannot be changed with the process and variety.
Long-slit positive pressure stretching is a new type of successful development in recent years. The equipments imported from Japan and the United States in the three factories of Liaohua, Zhangjiagang and Shaoxing in recent years are selected in this way, and the spinning method is also A long spinneret, one or several metering pumps, is relatively simple, especially for its stretching equipment, which uses a long strip-shaped small box through which fibers pass through the middle gap and is drawn by compressed air. The drafting box can also change its position up and down depending on the process and the variety, and its drafting speed can reach 6000-8000m/min, which makes the former several types of tensioners unattainable. The biggest advantage of this type of drafter is: drafting speed High, the equipment structure is relatively simple and easy to control, can adapt to a variety of different processes and varieties, fiber network is more uniform, is the current direction of airflow stretching equipment reform, its shortcomings are higher energy consumption, the horizontal tensile force of the cloth is lower, Room for improvement.