Polyester spunbond non woven products have the advantages of high strength, good weather resistance, good insulation performance and so on. They are more and more widely used in industry, health and other fields. This paper briefly introduces the main factors affecting the evenness of polyester spunbond non woven fabric.
The spinning technology of polyester spunbond non woven is similar to that of general polyester filaments, and it requires high moisture content of dry chips. Generally, it is specified that the moisture content of the slice after drying is ≤ 3 × 10-5, otherwise, during spinning, there will be continuous filament breakage, candle head filament and other phenomena. This will affect the normal production, and the untwisted yarn such as broken yarn and candle head yarn will float to the screen forming machine table with the air flow, thus affecting the uniformity of the non woven fabric surface.
When polyester spunbond non woven produces 150 g/square meter, 200 g/square meter and other high quantitative products at low speed, the product uniformity is relatively easy to control. With the improvement of production speed, the stable operation of equipment and precise control of process conditions are required. If low quantity products less than 30g/square meter are produced, the uniformity of products will be difficult to control.
Under the condition of consistent cloth width (3.5m), the greater the tow density per unit area, the better the uniformity of polyester spunbond non woven products. Select separately Φ 75mm × 0.22mm × 72 holes and Φ 75mm × 0.22mm × 120 holes spinneret is used to produce 60 g/square meter products. Under the same conditions of raw materials, spinning process, drafting speed, and the running speed of the web forming machine, the spinning experiment shows that the uniformity of the non woven fabric surface made of 120 holes spinneret is better than 72 holes; However, the more holes in the spinneret, the more difficult it is to cool the side air, and the more serious the interference between the tow, which will offset some beneficial factors brought about by the increase in the number of holes. Therefore, the porous number should not be pursued unilaterally.
The tow drafting speed is low, the drafting kinetic energy is insufficient, the monofilament size is large, the fiber is coarse, the number of cloud spots is large, and the cloth uniformity is relatively poor; When the inlet pressure is high (such as 0.50mpa), the drafting rate of the tow is correspondingly high, the drafting kinetic energy is large, the monofilament size is small, and the fiber is fine. However, the number of cloud spots is also relatively large. This is because with the increase of air inlet pressure, the draft air flow rate and flow rate increase, and the confluence formed with the surrounding air causes a strong impact on the screen forming machine, resulting in the increase of the unevenness of polyester spunbond non woven cloth.
In the production process of polyester spunbond non woven, in order to effectively improve the uniformity of products, we must adjust and improve from the aspects of chip moisture content, production speed, tow density and so on. Only with reasonable process and good production management can we produce high-quality polyester spunbond non woven fabric products.