JPH05186908A - Production of multifilament - Google Patents

Abstract

PURPOSE:To provide a direct spinning and drawing process for producing a polyolefin multifilament hating excellent strength and elongation. CONSTITUTION:The objective direct spinning and drawing process for multifilament comprises the cooling of a melt-spun polyolefin with a cooling duct 2, the application 4 of a lubricant, the cooling to 5-30 deg.C with a cooling roll 5 and the drawing with a pair of hot drawing rolls 6-1, 6-2. A multifilament having high strength and low elongation can be produced without dividing the drawing step from the spinning step.

Description

Detailed Description of the Invention

[0001]

[Field of Industrial Application] Multifilaments made of polyolefins such as polypropylene and polyethylene are used for raw yarns such as ropes, nets, pile yarns for carpets, and non-woven fabrics.

[0002]

2. Description of the Related Art In general, a thermoplastic resin multifilament is composed of a large number of molten filaments discharged from a die by several meters.
While cooling in the atmosphere flow using the following cooling duct 3
It is manufactured by applying a draft at a relatively high speed of about 00 m / min, taking it out, and stretching and crimping in a separate process. In recent years, a method of continuously performing spinning, drawing, and crimping, that is, a direct spinning / drawing method has been devised by improving the performance of a winder. In this case, a high-strength multifilament having sufficient fiber strength is obtained. I couldn't do that.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a high-strength, high-strength polyolefin multifilament by a direct spinning / drawing method.

[0004]

Means for Solving the Problems As a result of various studies, the present inventors have conducted various studies in order to develop a method for producing a high-strength polyolefin multifilament by a direct spinning / drawing method.
The polyolefin is melt-spun and air-cooled using a cooling duct, followed by cooling with a cooling roll having a surface temperature of 5 to 30 ° C., and then continuously in-line at a surface temperature of 80 to 150 ° C.
The problem could be solved by stretching at a high ratio with the heating roll of No.

Examples of the polyolefin used in the present invention include low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, poly-1-butene, poly-4-methylpentene and the like. The polyolefin may be any one as long as it can be melt-extruded to form an aggregate of filaments, and the molecular weight, density, molecular weight distribution and the like are not particularly limited.

Next, a method for carrying out the present invention will be described. FIG. 1 shows an example of an apparatus according to the present invention. The polyolefin is discharged from the spinning nozzle 1 by the extruder to form the unstretched multifilament 3. It is desirable that the molding temperature be as high as possible within a range in which the aggregate of filaments can be molded and processed without deterioration of the polyolefin. The nozzle used here is preferably one in which each discharged filament is cooled uniformly.

The spun undrawn multifilament is cooled and solidified in the cooling duct 2. The cooling here may be such that the single filaments are not fused to each other, and the temperature of the cooling duct is preferably 5 to 40 ° C. and the wind speed is preferably 0.1 to 0.5 m / min. After cooling, the oiling agent is applied by the oiling roller 4.

The multifilament to which the oil agent is applied is cooled by a cooling roll. As the cooling roll, a nip roll or the like is used in addition to the godet roll. The surface temperature of the cooling roll needs to be 5 to 30 ° C, preferably 5 to 20 ° C.

The surface temperature of the chill roll has a very large effect on the linear strength of the multifilament. Conventionally, even if it is used as a simple take-up roll, it is not known to actively cool it like the present invention, and it has not been known that this cooling greatly improves the physical properties of the multifilament. . Water, brine, etc. are used for cooling, and a circulation system is desirable.

The multifilament cooled by the cooling roll is drawn by the heating roll, and the drawn multifilament is cooled by the cooling godet roll 7 and then wound up into a product. A godet roll, a nip roll, or the like is used as the heating roll, and may be stretched in multiple stages. The stretching temperature is usually 80 to 150 ° C., and particularly 100
~ 140 ° C is preferred. The stretching ratio is 8 to 15 times, which is a high stretching ratio. If it is less than 8 times, the strength is low, and it is difficult to stretch it more than 15 times.

[0011]

【Example】

(Example 1) MFR 7.8 / 10 min (ASTM D
1238, L) polypropylene (show allomer:
Using TA553-4, Showa Denko KK, 0.6m
Extrusion temperature of 280 ° C., 35 using a 40 mmφ extruder from a multifilament spinning nozzle having mφ and 68 holes.
Extrude at a discharge rate of g / min. The extruded unstretched multifilament has a cooling temperature of 18 ° C and a cooling air velocity of 0.5 m.
/ Min, 900 mm in length of the cooling duct, after applying an oil agent with an oiling roller, the peripheral speed of 35 m / mi kept at a surface temperature of 15 ° C by circulating water.
After cooling with an n cooling godet roll, it was heated with a pair of stretching rollers having a surface temperature of 120 ° C. and wound up at 300 m / min. When the tenacity and elongation of the obtained multifilament were measured, the linear strength was 8.0 g / d and the elongation was 14%.

(Example 2) When a cooled godet roll maintained at a surface temperature of 5 ° C was used in Example 1, the obtained multifilament had a linear elongation of 9.0 g / d and an elongation of 12 %Met.

(Comparative Example 1) The same resin as in Example was used, and after the oil agent was adhered, it was directly introduced into the pair of stretching rollers at a speed of 35 m / min without passing through the cooling godet roll-1, and the stretching temperature was 1
When stretching was performed at 20 ° C, the maximum stretching speed was 140 m /
I could only raise it to min. When the strength and elongation of the obtained multifilament was measured, the linear strength was 3.8 g /
d, the elongation was 140%, and only low strength multifilaments were obtained.

(Comparative Example 2) When a cooled godet roll maintained at a surface temperature of 40 ° C. was used in Example 1, the multifilament obtained had a high elongation of 3.5 g.
/ D, the elongation was only 170%.

[0015]

According to the method of the present invention, high-strength multifilaments can be obtained by the direct spinning / drawing method without dividing the spinning / drawing steps.

[Brief description of drawings]

FIG. 1 shows an example of a molding apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle 2 Cooling duct 3 Unstretched multifilament 4 Oiling roller 5 Cooling godet roll-1 6-1 First heating godet roll 6-2 Second heating godet roll 7 Cooling godet roll-2 8 Stretching multifilament 9 Winder

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location D02J 13/00 F (72) Inventor Takeshi Sano 3-2 Chidori-cho, Kawasaki-ku, Kanagawa Prefecture Akira Inside the Kawasaki Resin Research Laboratory, Wadeko Co., Ltd.

Claims (1)

[Claims] 1. A polyolefin is melt-spun, air-cooled by using a cooling duct, and then cooled by a cooling roll having a surface temperature of 5 to 30 ° C., and then continuously in-line by a heating roll having a surface temperature of 80 to 150 ° C. A method for producing a multifilament, which comprises high-stretching.