JPH0329882B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing non-foamed, high strength, high denier monofilaments. Conventionally, non-foamed general monofilament was molded by melt extruding thermoplastic resin through a nozzle with a perfect circular cross-section, usually passing it through a cooling water bath, or solidifying it using a treatment bath as necessary. Make a thread and heat it at the optimum temperature depending on the resin used.
Manufactured by stretching at a low stretching ratio of ~10 times, the linear strength of a 400 denier product is 2 g/d ~ 7 g/d.
d is obtained. Furthermore, when forming a high-strength monofilament, a linear strength of 12 g/d or more (400 denier or less) is obtained by performing a high stretching ratio of 11 to 20 times. In this case, since high-magnification drawing is performed, if a product with a 400 denier level is to be obtained, the undrawn yarn fineness will be nearly double that of general monofilament molding. Air bubbles are likely to be generated, and these air bubbles result in stretching breakage. Furthermore, when it comes to high-strength, high-denier yarns of 800 deniers or more, the undrawn yarn fineness is several times that of general monofilament molding, and the frequent occurrence of vacuum bubbles makes it almost impossible to spin. As a measure to eliminate vacuum bubbles generated during spinning cooling, for example, Japanese Patent Publication No. 51-32724 describes the ratio of the long axis a to the short axis b of the extrusion nozzle hole (a/
b) Thick denier monofilament molding in which several nozzles with a diameter of 1.8 to 4.0 and an area πab of 3.14 mm ² or more are arranged at intervals with the long axis of the extrusion nozzle hole aligned with the circular line of the nozzle base. In addition, in Japanese Patent Publication No. 55-3442, there is an invention called ``Nozzle for manufacturing'', and ``When manufacturing monofilament of 1,000 to 10,000 deniers from polyolefin synthetic resin, the ratio of the long side to the short side is 2:1 to 5. An invention entitled "A method for producing a polyolefin-based synthetic resin monofilament characterized by using a nozzle having a rectangular cross-sectional view such as: 1" is described. What these conventional techniques have in common is that by using these nozzles, a product with a linear strength of 6 to 7 g/d and about 10,000 d can only be obtained by stretching about 10 to 12 times. In order to obtain a high-strength yarn with a linear strength of 12 g/d or more, it is necessary to further draw the yarn at a high magnification, but the above techniques have limitations in eliminating vacuum bubbles.
In addition to frequent drawing breaks, problems such as yarn wobbling in the spinning section and clouding of the filament during high-strength drawing occur, making it impossible to obtain a high-strength, high-denier yarn. On the other hand, as conventional techniques for increasing the denier, for example, Japanese Patent Publication No. 48607/1983 and Utility Model Publication No. 46-48607,
As seen in inventions such as Publication No. 31966, there are connected fibers. However, the above-mentioned techniques for manufacturing connected fibers are only capable of drawing by a factor of 12 times or less, and have the fatal drawback that the connecting yarns will split when stretched at a high magnification of about 20 times. That will happen. The present invention was achieved as a result of various studies to improve the above-mentioned circumstances, and the object of the present invention is to provide a method for producing a high-strength, high-denier monofilament using a specially shaped nozzle. That is, the present invention provides a single hole in which the ratio (a/b) between the long axis a and the short axis b of the extrusion nozzle hole is 1.2 to 1.6, and the cross-sectional area π/4ab is less than 3.14 ^mm2 , in the direction of the short axis b. The stacking interval is
A method for manufacturing non-foaming, high strength, high denier monofilament using a plurality of stacked nozzles of 0.1b to 0.3b. The invention will now be explained in conjunction with the drawings. FIG. 1 illustrates a principle diagram (cross-sectional diagram) of a single hole which is an element of a nozzle used in the present invention.
FIG. 2 is a principle diagram showing one embodiment of the nozzle used in the present invention, and shows an example in which two single holes as elements are overlapped. Each single hole has a long axis a
It is necessary to satisfy that the ratio (a/b) of and short axis b is 1.6 or less, and the cross-sectional area π/4ab is less than 3.14 mm ² . If the (a/b) ratio exceeds 1.6, the single holes themselves will be quite flat, and if multiple holes are piled up, it will become a thin and easily split non-foamed monofilament, which may cause problems with yarn sway in the spinning section during molding. , troubles such as twisting of the filament during stretching are likely to occur. At the same time, when the cross-sectional area is more than 3.14mm ² ,
By stacking a plurality of pieces, sufficient spinning pressure cannot be obtained, and they tend to break just below the nozzle, resulting in poor yield. In view of the above, the single hole serving as the element of the nozzle of the present invention is an ellipse or an oblong with a ratio (a/b) of major axis a to minor axis b of 1.2 to 1.6, and a cross-sectional area of 3.14 mm ² It is appropriate that it is less than In FIG. 2, the long axis of one single hole is shown as a, and the long axis of the other single hole is shown as a'. The nozzle used in the present invention has these single holes arranged in the direction of the minor axis b, with an overlapping interval as shown in Fig. 2.
They have a length of 0.1b to 0.3b and are formed by overlapping a plurality of them (two in the embodiment shown in FIG. 2). In addition, in Fig. 3, the overlap interval d or d' is 0.1b to 0.3b, and a/b is
An explanatory diagram of three 1.0 single holes stacked in the axis b direction is shown for reference, but in the present invention, a/b is
As mentioned above, an ellipse or an ellipse of 1.2 to 1.6 is preferable. In addition, the overlap distances d and d' may be different or the same as long as they satisfy the condition of 0.1b to 0.3b, but usually d=d'. It is preferable that there be. In the present invention, they are not overlapped in the short axis b direction,
As shown in FIG. 4, when stacked in the direction of the long axis a, the monofilament becomes extremely flat, which often deviates from its definition and use as a monofilament in the usual sense, so it was excluded. 0.1b~ at the same time
It is necessary to overlap them with a spacing d of 0.3b, and in this case, if the spacing is less than 0.1b, they tend to split during high-magnification stretching. Moreover, if it exceeds 0.3b, vacuum bubbles are likely to be generated during the cooling process, resulting in increased stretching breakage. The number of stacked single holes is not limited, but is generally 10 or less, and particularly preferably 2 to 3 when high strength is desired. Furthermore, although the nozzle holes may be arranged in any manner, it is particularly preferable that the short axes b of the extrusion nozzle holes coincide with the circular line of the nozzle base, and the extrusion nozzle holes are arranged at equal intervals. This is because if they are arranged in the opposite manner, the effect of eliminating the deviation of heat shrinkage during the cooling process of the undrawn yarn will be reduced. The present invention not only makes it possible to manufacture non-foamed high strength and high denier monofilament, which was impossible with conventional non-foamed monofilament nozzles, without changing the conventional process, but also There is almost no thread wobbling,
In addition, it exhibits a number of effects such as not splitting even when stretched at high magnification. Although there is no particular restriction on the product denier, it is highly effective when obtaining products with a denier of 400 or more. Moreover, the filament obtained by the present invention is
Not only is it highly strong and has a high denier, but it is also highly flexible and has an appropriate strength before splitting, so even when it is twisted into yarn, it does not become fluffy. The thermoplastic resin that can be applied when producing a filament using the nozzle of the present invention is not particularly limited as long as it can be melt-spun, such as nylon, polyester, polyethylene, polypropylene, etc. Polyethylene has a melt index of 0.1g/10min to 2.0g/
10 min, density 0.950 to 0.960 g/cm ^3rd place is preferred. Such resin may be a copolymer with a different type of monomer, and may also contain antioxidants, lubricants,
It may also contain ultraviolet absorbers, matting agents, stabilizers, colorants, foaming agents, flame retardants, and the like. The present invention will be explained in more detail below by giving Examples and Comparative Examples. Examples 1-2, Comparative Examples 1-5 Under the conditions shown below, high-density polyethylene with a melt index (JIS K6760) of 0.51 g/min and a density of 0.953 g/cm ³ was processed using the nozzle shown in Table 1. After melt extrusion, rapid cooling, and multistage drawing, a yarn was produced. The results obtained are shown in Table 2. Note that the following conditions are common to each Example and each Comparative Example. Moreover, the shape of the nozzle is an ellipse. Extruder: 50mmφ L/D=24 Screw: Compression ratio 4.0 Breaker plate: 2.0φ×130H Screen pack: 80, 100, 120, 150, 100 mesh Total of 5 pieces Extruder temperature: C ₁ 160, C ₂ 250, C ₃ 290, D ₁ 290,
D ₂ 290 (°C) Air gap: 8cm Cooling tank temperature: 15°C Stretching temperature: 1st stage 100°C Wet 2nd stage 115°C Heating roll 3rd stage 115°C Heating roll 4th stage 140°C Heating roll production amount: 20Kg/ Hr~40Kg/Hr Number of winder weights: 30 weights Monofilament physical property measurement method: JIS L1070
According to 1073.

【table】

[Table] From the results shown in Table 2 above, the following can be seen. That is, in Comparative Example 1, the cross-sectional area is outside the conventional range used in the present invention, and since non-foaming molding is performed using a nozzle that does not overlap single holes, thread breakage occurs under the nozzle and during stretching. However, the strength of the sample yarn obtained was also low. Since Comparative Example 2 uses a conventional nozzle for connecting fibers, the drawn yarn splits during high-magnification drawing, making sampling impossible. In comparative example 3,
Since the nozzle has single holes stacked one on top of the other in the direction of the long axis a, the yarn sways to a large extent, the yarns intersect with each other, and spinning is impossible. In Comparative Example 4, a/b of each single hole was
Since the value exceeds 1.6, thread shaking and filament twisting occur frequently, making sampling impossible. In Comparative Example 5, since the cross-sectional area π/4ab of each single hole exceeded 3.14 mm ² , nozzle breakage occurred frequently and spinning was impossible. Therefore, by using the nozzles of Examples 1 and 2, it is possible to manufacture a monofilament with high strength and high denier.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a single hole that is an element of a nozzle. a represents the length of the major axis, and b represents the length of the minor axis and the axis. FIG. 2 is a principle diagram showing one embodiment of the nozzle used in the present invention. FIG. 3 is an explanatory diagram showing a reference example. d and d' represent overlapping intervals.
FIG. 4 is a cross-sectional view of the single holes when they are superimposed in the long axis a direction.

Claims (1)

[Claims] 1. The ratio of the long axis a to the short axis b of the extrusion nozzle hole (a/
A non-foaming, high-strength nozzle that uses multiple single holes with a b) of 1.2 to 1.6 and a cross-sectional area π/4ab of less than 3.14 mm ² stacked in the short axis b direction at stacking intervals of 0.1 b to 0.3 b.・Production method of high denier monofilament.