What are the Working Temperature and Pressure Requirements of PET Nonwoven Fabric Making Machine?

In the world of nonwoven fabric production, the PET nonwoven fabric making machine plays a crucial role. As industries increasingly rely on nonwoven fabrics for various applications, understanding the working temperature and pressure requirements of these machines becomes essential.

1. Raw material processing stage

Temperature requirements: The pre-crystallization treatment temperature of PET chips is usually 120-160℃, and the time is 20-60 minutes. The purpose of this step is to improve the crystallinity of PET chips, stabilize their physical properties, and prevent excessive degradation or deformation in subsequent processing. If the pre-crystallization temperature is lower than 120℃, the chips are not fully crystallized, and bubbles are easily generated during the extrusion process due to uneven heating; if it is higher than 160℃, it may cause the chips to melt prematurely, affecting the subsequent screw conveying. The drying temperature is also 120-160℃, and the drying time is 3-12 hours.

Pressure requirements: The pressure requirements at this stage are relatively unobtrusive, but in some automated feeding systems, there will be certain air pressure requirements to ensure that the material is stably transported to the subsequent equipment. Generally, the air pressure is maintained at 0.4-0.6MPa to ensure that the material can be smoothly transported from the silo to the hopper of the screw extruder.

2. Screw extrusion stage

Temperature requirements: The screw extruder needs to extrude and melt the PET slices into a uniform melt. The temperature control of each zone is very critical. Usually, the temperature gradually increases from the hopper end to the die head. For example, the temperature of the first section near the hopper may be set at 220-240℃, which is mainly for the initial softening of the slices; the temperature of the middle section is 250-270℃ to further melt the slices; and the temperature near the die head is generally 260-280℃ to ensure that the melt has good fluidity for smooth extrusion. The temperature control of each zone uses a temperature control module, solid-state relay, and Pt100 platinum thermal resistor to form a temperature control closed-loop system to ensure precise temperature control.

Pressure requirements: When the screw rotates to push the material forward, a certain pressure will be generated. This pressure must ensure that the melt can overcome the resistance of the subsequent equipment and be extruded smoothly. Generally, the melt pressure of the screw extruder is 10-20MPa.

3. Spinning and subsequent stages

Temperature requirements: The melt coming out of the screw extruder enters the spinning assembly after being accurately measured by the metering pump. The temperature of the spinning assembly is generally controlled at 280-320℃, so that the melt is extruded from the spinneret hole in a thin stream to form a filament. The temperature of the hot air is 280-380℃, which is used to stretch and cool the newly extruded filaments to quickly shape the filaments. In the thermal bonding process, if hot roller thermal bonding is used, the roller temperature is generally 110-150℃, and the specific temperature depends on the gram weight of the PET non-woven fabric, the thickness of the fiber and other factors. For some special-purpose PET non-woven fabrics, such as those used for filter materials, the operating temperature of the dust filter is 160-240℃.

Pressure requirements: During the spinning and stretching process, the pressure of the stretching air is 0.05-0.3MPa. The appropriate pressure can stretch the filaments evenly to the required fineness. During the hot roller thermal bonding, the pressure between the rollers is generally 0.2-0.5MPa.

As a leading Lieferant für Maschinen zur Herstellung von Vliesstoffen, Aolong Nonwoven specializes in providing high-quality PET nonwoven fabric making machines.Whether you need help with PET-Vliesstoff-Herstellungsmaschines or have any other queries, feel free to contact us to discuss our products and how we can be of help to you!