JP3036947B2 - Multifilament manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Multifilaments made of polyolefins such as polypropylene and polyethylene are used in ropes, nets, pile yarns of carpets, and raw yarns of nonwoven fabrics.

[0002]

2. Description of the Related Art Generally, polyolefin multifilaments are prepared by cooling a large number of molten filaments discharged from a die in a cooling air duct at a cooling air velocity of several m / sec or less while cooling at about 300 m / min. It is manufactured by drafting at high speed and drawing and crimping in separate steps. In recent years, a method of continuously performing from spinning to drawing and crimping by improving the performance of a winder, a so-called direct spinning / drawing method has been devised.
A high-strength multifilament having sufficient fiber strength could not be obtained.

[0003]

An object of the present invention is 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 The present inventors have proposed direct spinning and spinning.
Various studies were conducted to develop a method for producing a high-strength polyolefin multifilament by a drawing method. As a result, polyolefin was melt-spun and cooled by a cooling duct.
The subject was able to be solved by rapidly cooling with a sizing agent applying roller at 〜１０10 ° C., and after applying the sizing agent, continuously heating it in-line with a heating roll at 80 to 150 ° C. and stretching it at a high magnification.

The polyolefin used in the present invention includes low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, poly 1-butene, poly 4-methylpentene and the like. The polyolefin is not particularly limited as long as the polyolefin can be melt-extruded to form an aggregate of filaments, and the molecular weight, molecular weight distribution, density, 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 the device according to the present invention. The polyolefin is discharged from the spinning nozzle 1 by an extruder to form an undrawn multifilament 3. The molding temperature is desirably as high as possible within a range where the polyolefin used can be spun and does not decompose. The nozzle used here is preferably one in which each discharged filament is uniformly cooled.

[0007] The spun undrawn multifilament is cooled in a cooling duct 2. The cooling here is sufficient that the single filaments do not fuse with each other, and the temperature is 5 to 40 ° C.
The wind speed is desirably in the range of 0.1 to 0.5 m / min.

[0008] The undrawn multifilament cooled by the cooling duct is rapidly cooled by the cooled sizing agent applying roller, and the sizing agent is applied. The temperature of the sizing agent applying roller needs to be 0 to 10 ° C, and preferably 0 to 5 ° C. The sizing agent used is not particularly limited as long as it does not solidify or denature in the range of 0 to 10 ° C.

[0009] The temperature of the sizing agent application roller has a very large effect on the linear strength of the multifilament. Conventionally,
Even when the roller is simply used as a sizing agent applying roller, it is not actively cooled as in the present invention, and it has not been known that this cooling significantly improves the physical properties of the multifilament. Water, brine, etc. are used for cooling, and it is desirable to use a circulation system.

[0010] The multifilament cooled by the cooling roll is drawn by a heating roll, and the drawn multifilament is cooled by a cooling godet roll 6 and 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 from 80 to 150 ° C, especially 100 ° C.
~ 140 ° C is preferred. The stretching is performed at a high stretching ratio of 8 to 15 times. 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 aroma)
TA553-4, manufactured by Showa Denko KK)
It is extruded at a discharge rate of 120 g / min from a multifilament spinning nozzle having mφ and 68 holes using a 40 mmφ extruder. The extrusion temperature is 280 ° C. The extruded undrawn multifilament is cooled by a cooling duct having a cooling temperature of 18 ° C., a cooling air velocity of 0.5 m / min, and a length of 900 mm, and then cooled to 5 ° C. by a cooling sizing agent applying roller having a peripheral speed of 3 m / min. After quenching and applying the sizing agent, it is wound at 300 mm / min with a pair of stretching rollers, and 2,000 m / m
Stretching was performed at an in speed. When the strength and elongation of the obtained multifilament were measured, the linear strength was 7.0 g / d,
The elongation was 20%.

(Example 2) In Example 1, 1500 m / m was used by using a sizing agent applying roller cooled to 10 ° C.
When stretched in, the obtained multifilament had a linear elongation of 6.0 g / d and an elongation of 40%.

Comparative Example 1 Using the same resin as in Example 1,
When stretching was performed without cooling the sizing agent application roller, the stretching speed could only be increased to 1000 m / min. When the strength and elongation of the obtained multifilament were measured, the linear strength was 3.5 g / d and the elongation was 150%, and only a low strength multifilament was obtained.

[0014]

According to the method of the present invention, a high-strength multifilament can be produced by the direct spinning / drawing method without separating the steps of spinning / drawing.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle 2 Cooling duct 3 Undrawn multifilament 4 Coolant adhering oiling roller 5-1 First heating godet roll 5-2 Second heating godet roll 6 Cooling godet roll 7 Drawing multifilament 8 Winding machine

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI D02J 1/22 D02J 1/22 K (58) Investigated field (Int.Cl. ⁷ , DB name) D01F 6/00-6 / 96 D01D 1/00-13/02

Claims (1)

(57) [Claims] 1. A polyolefin is melt-spun at a melting temperature of 230 to 290 ° C. at a die portion, quenched by a sizing agent applying roller cooled to 0 to 10 ° C., and continuously in-line after the sizing agent is applied. Surface temperature 80-150 ° C
The method for producing a multifilament, which is heated by a heating roll and stretched at a high magnification.