Polyester Staple Fiber Manufacturing Process

Polyester Staple Fiber (PSF) is made directly from PTA and MEG or PET Chips or from PET/Polyester waste and post consumed PET bottles，It’s used for spinning yarns and making geotextiles, as well as fill pillow, stuff toys, cushions ,etc. For polyester staple fiber producing machine, The only different is raw material processing machine . Virgin fiber will be used in PTA, and recycled will be used PET. Now We will use PET flakes as raw materials to illustrate how to produce polyester staple fiber as below:

The Whole production line can be divided into two parts, spinning line and finishing line. 

There are five steps that need to be done in spinning line.

Dry

PET flakes, pop corn material, lump will be dried by the vacuum dryer (No.1) or continuous dryer with fixed temperature. The air is suctioned out by vacuum pump and flake is dried in the vacuum state.

Melting

PET bottle flakes are fed into screw extruder (No.3) by meaning of melted, mixing and filtering (No. 4) from hopper after being heated and dried,The melted PET will go through filter to remove the impurity, like PVC and other materials,The melt goes into spin beam (No.6) in which specially-designed distribution piping system guarantees same dwell time and same pressure drop for the melt to reach each spinning position.

Quenching

The melt becomes small stream after being extruded from micro-holes of spinneret and are cooled and solidified by air flow after passing through a low-damping quenching (No. 7). The melt stream sprayed from spinneret become plastic shape monofilament in very short time and the structure is changed. This changing is mainly influenced by velocity evenness of air flow from quenching. Air temperature and velocity, control of air blowing gap and air flow steady under high velocity affect the direct factor of yarn quality. Therefore, it requires air flow from quenching with stability, uniformity and adjustability.

 

Winder

The cooled and solidified filaments are oiled and damped by oiling device (No. 9) to increase the cohesion of the yarn, to improve the antistatic property of the yarn, to reduce the friction between the yarn and the yarn, and also to reduce the friction between the yarn and equipment, and to improve the after-treatment property of the yarn,After passing through winder, the yarn from every position is guided by godet roller to the end of take up unit and is entered into drawing-off roller (No.10), then is fed into Tow Can by sunflower rollers (No.11). Six-roll drawing-off and sunflower wheels are driven by synchronous motor. The engaged depth of two sunflower rollers is adjustable. The drawing-off and sunflower rollers are with low speed set for yarn string-up and easy operation. Spinning and take-up system is set with collective communication system.

 

Can unit

Can traversing unit (No. 12 &12A) is driven by A.C. motors, which realizes to transporting change of empty can, reciprocating movement of tow can and delivery of laden can. This unit has two kinds of control: manually (except reciprocating movement) and automatic. When tow can reaches certain weight by time setting, the programmable-control time counter gives off a signal, and then reciprocating mechanism automatically moves laden can to the center of the unit and delivering mechanism moves laden can out, in meanwhile, to move in empty can for continuous tow collection. Then the tow in can will be balanced and sent to after-treatment process.

 

The second part is finishing line, there are also generally five steps.

Creel stand

The tow creel is arranged for 4 rows, in which, two rows of them are put into using and the other two rows are preparing.The tows from Tow creel are divided into 3 nos. sheets for drawing. The tow cable come from the creel is guided firstly by Tow guide frame and passed through dip bath in order to split tow sheets evenly with certain width and thickness, and ensure more even spin finish in tow sheets, and then start the drawing process.

Stretcher

The range uses 2-stage drawing technology. The first drawing stage carries out between the first stretcher and the second stretcher. The temperature of Draw bath is about 60℃～80℃. The draft ratio of the first drawing stage is completed 80%～85%. The second drawing stage carries in Steam box chest between the second stretcher and the third stretcher. The draft ratio of the second drawing stage is completed 15%-20%.

 

Stacker and crimper

After cooled and oiled, the tow sheets are sent into Tow stacker, 2 or 3 tow sheets are stacked into 1 tow sheet. The tilt angle of stacking rollers is adjustable for achieving stacking process. The width of the tow sheet and the quality of stacking is special important for crimping. After stacking, the tow sheet is sent into Crimper through Tension control roller and Steam pre-heating box. The tow sheet is crimped through squeezing to assure the good performances of fiber in later process.

Relax and heating setter

After crimping, the tows spread to chain board type conveying of Relaxing dryer. The tows are dried evenly by blowing of forced air, shape is finalized here and then cooled down below glass temperature.

Baler

After relaxer, the tows are dragged to upper floor for cutting by Tension stand, which also guarantees the tows under tension evenness to feed Cutter in tangential direction of cutting reel. The tows are cut into fixing length of staple by adopting press cutting. After cutting, the cut fibers enter into baler chamber in gravity or through conveyor for baling, and then the bale is weighting, manual baling and labeling and then sent to the storage by fork lifter.