The existing polypropylene staple fiber production line, the equipment and process used belong to one-step spinning, also known as short-range spinning, and the process route is feeding, screw extruder, spinning machine, refrigerator, winding machine, one drafting machine, Electric heating circulating air box, two-stage drafting machine, wire stacking machine, curling machine, oven and hot air boiler, cutting machine, baler.

The raw materials are put into the screw extruder for extrusion, friction and melting, so that the polypropylene crystal structure is fully melted to produce physical changes, and the tow is spun through the spinning machine to cool and form, and then go through winding, a draft machine, and a second draft. machine, which produces drafting. During the drafting process, the tow passes through the drafting roller and the electric heating circulating bellows of the first drafting machine. The tow is heated and softened and the tissue structure changes. With the increase of the drafting ratio between the first and second drafting machines , the breaking strength of the tow is relatively increased, and the elongation is decreased. When the draft ratio reaches a certain level, if the draft ratio is increased, the tow will break. Generally, 3 denier fibers are produced, the breaking strength is 3.2CN/DTEX, and the elongation is 65%. In the above-mentioned production process, the first drafting machine 1, the electric heating circulating air box 2 and the second drafting machine 3 are used; due to the concentration of the drafting stress in the first drafting, the tow is unbearable, and it is easy to produce broken wires; the electric heating circulating air box is adopted. , it is easy to evaporate the water contained on the surface of the tow, which is not conducive to the change of the tow draft and the tissue structure.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a production process and a production line that can improve fiber properties. For this reason, the present invention proposes a kind of polypropylene staple fiber production process, comprises the following steps:

Drafting, two drafting, force mouth temperature softening, three drafting.

In the above-mentioned production process of polypropylene staple fiber, a preheating softening process is also provided between the first drafting and the second drafting. Or between the first drafting and the second drafting, a preheating soft

4 dagger and oiling process.

In the above-mentioned production process of polypropylene staple fibers, the preheating and softening process adopts a water bath. Or the preheating softening and oiling process adopts a water bath. The heating and softening process adopts a steam box.

At the same time, the present invention provides a polypropylene staple fiber production equipment, including a first drafting machine, a second drafting machine, a heating and softening device and a third drafting machine, which are connected in sequence.

3. The above-mentioned polypropylene staple fiber production equipment also includes a preheating and softening device, which is arranged between the first drafting machine and the second drafting machine. The preheating and softening device is a water bath.

In the above-mentioned polypropylene staple fiber production equipment, the heating and softening device is a steam box.

The present invention decomposes the first draft into two drafts, disperses the force and accumulates the original draft.

It can overcome the defect of wire breakage caused by stress concentration, reduce the elongation and improve the breaking strength of the fiber.

In the present invention, a water bath is added, and the tow passes through the water bath from the first drafting machine to the second drafting machine, and the tow is preheated, drawn and oiled to improve the activation and smoothness of the tow structure. ,

Change the arrangement direction of the molecular structure; replace the electric heating circulating bellows of the prior art with a steam box, which not only ensures that the surface of the tow contains moisture, but also softens the tow at high temperature, so that the organizational structure is fully changed, and the breaking strength of the fiber is further improved. Decrease elongation.