Polypropylene twisted yarn is an industrial textile material made from polypropylene fibers through a twisting process. This material holds an important position in the textile industry. With its unique performance characteristics, it has demonstrated significant advantages in multiple application fields.
The production process of polypropylene twisted filament is a systematic one, mainly including key links such as melt spinning, drawing and twisting, and post-treatment. The entire process flow, from raw material preparation to finished product packaging, each step directly affects the quality of the final product.
I. Melt Spinning process
The production of polypropylene twisted filament begins with the melt spinning of polypropylene raw materials. The raw material slices first enter the screw extruder and are melted into a melt at a temperature of 220-280℃. Screw extruders are typically divided into multiple heating zones. The temperature of the first zone is set at 220℃, and the temperature from the second zone to the spinning box is set at around 265℃. The pressure at the top of the screw is controlled at 5MPa. After being precisely metered by the metering pump, the melt is extruded through the spinneret to form primary fibers.
During the spinning process, the cooling process is of vital importance. After the melt is extruded from the spinneret, it is cooled and solidified into shape in a 1.84-meter-long side-blowing air window. The cooling air temperature is usually controlled at 12-20℃, and the wind speed is 0.34-0.35 meters per second. The cooled filament bundle is oiled through two oil rollers and wound at a speed of 350 meters per minute to become raw filament. The original filament needs to be balanced at 25℃ for 48 hours to eliminate internal stress and facilitate subsequent drawing processing.
Ii. Stretching and Twisting process
Drawing and twisting is the core process in the production of polypropylene twisted filament. The balanced raw silk enters the spindle-type drawing and twisting machine for two-stage traction and twisting. The filament bundle is first wound onto the first hot roller through the guide hook and the feeding roller, with the temperature of the first hot roller set at 75℃. Then it is wound into the second hot roller, and the temperature rises to 145℃. The speed ratio of the second hot roller to the first hot roller is more than 5.5 times, forming Zone I stretching.
After being wound several times on the second hot roller, the filament bundle is wound onto the third guide roller through the shaping plate. The speed ratio of the third guide roller to the second hot roller is less than 1.25 times, forming Zone II stretching. The stretching speed should be controlled at 150 to 300 meters per minute, and the total stretching ratio should reach more than 7 times. After the filament bundle is wound several times on the third guide roller, it is wound at a spindle speed of 5000rpm and eventually becomes the drawing and twisting compound filament.
Iii. Key Points for Process Parameter Control
During the production process of polypropylene twisted yarn, each process parameter needs to be precisely controlled. The temperature of the spinning melt is usually controlled at 265-275℃, with a melt flow index (MFI) of 5-40 and a molecular weight distribution index (MWD) of less than 7. The spinneret aperture is 0.35mm, the number of holes is 120, and the hole length-to-diameter ratio I/D is 4. In the side-blowing air cooling process, the air temperature of 12-20℃ and the air speed of 0.34-0.35 meters per second are the key parameters to ensure the quality of fibers.
In the drawing process, the temperature difference control of the first hot roller at 75℃ and the second hot roller at 145℃, as well as the setting of a drawing ratio of more than 7 times, directly determine the orientation and strength of the fibers. The speed of twisting ingots is usually controlled at 1800-2100 RPM, and the twist direction can be selected as Z twist or S twist. A reasonable combination of process parameters can produce high-strength polypropylene filament with a fineness of 400-1600 decibels and a breaking strength of over 8.56CN/dtex.
Guangdong Qingyuan Yitong Weaving Co., Ltd. specializes in the production and sales of pp yarn, polypropylene high strength yarn, polypropylene light body yarn, polypropylene high strength yarn, 300D polypropylene polypropylene yarn, polypropylene network yarn, polypropylene twist yarn, 300D polypropylene high strength yarn, 1200D polypropylene high strength yarn, anti-aging polypropylene yarn, anti-static polypropylene yarn, Yitong polypropylene twist yarn, etc.
Qingyuan Yitong weaving Co., LTD
Website: http://www.gdytzz.com
Domestic business: He Shanbin
Tel: 0763-6812222
Fax: 0763-6813888
Mobile: 133 5289 9993
Foreign business: Landy
Tel: 0763-6813199
Mobile: 135 5399 2535
