JPS597801B2 - Manufacturing method of polyamide monofilament - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyamide monofilament having high knot strength and excellent transparency.

Polyamide monofilaments used in fishing nets, strings, guts, etc. are required to have not only linear strength but also high knot strength and excellent transparency.

Conventionally, polyamide monofilaments for this purpose have been produced by extruding molten polyamide, setting the first stage stretching ratio to 3 to 4 after quenching, performing a second stage stretching at a higher temperature, and then heat setting. Manufactured.

In order to particularly improve transparency, it is considered desirable to instantaneously cool the melt-extruded polyamide, and efforts are being made to shorten the time it takes from the spinning nozzle to reach a coolant such as water as much as possible. Usually, it is rapidly cooled in a short time of around 0.3 seconds.

However, the polyamide monofilament produced in this manner was still not sufficient in terms of knot strength and transparency.

As a result of various studies to improve these points, the present inventors found that, contrary to the conventional thinking as described above, when molten polyamide is spun, held for a predetermined period of time, and then rapidly cooled, They discovered that polyamide monofilaments with excellent knot strength and transparency can be easily produced, and completed the present invention.

That is, the purpose of the present invention is to industrially advantageously produce polyamide monofilaments with excellent physical properties. In the method for manufacturing a polyamide monofilament by quenching the polyamide and then drawing it, the quench is achieved by performing the quenching 0.6 to 1.2 seconds after extruding the molten polyamide from a spinning nozzle.

To explain the method of the present invention in detail, polyamides used in the method of the present invention include polyamide 6 and polyamide 66.
, polyamide 6.10, polyamide 6.12, polyamide 6/66 copolymer, or a mixture thereof, among which polyamide 6/66 copolymer is particularly preferred.

In addition, these polyamides may contain lubricants, dyes,
Additives such as coloring agents such as pigments, weather resistance improvers, and antistatic agents may also be included.

These polyamides are usually supplied to an extruder in the form of pellets, melted, and then extruded from a spinning nozzle with a hole diameter of about several mm.

The extrusion from this spinning nozzle is preferably carried out so that the thickness of the so-called product monofilament, which has undergone all the manufacturing steps up to the drawing treatment, has a thickness of 4,000 to 40,000 deniers.

The extrusion diameter of molten polyamide to obtain a monofilament smaller than 4,000 deniers is too small;
If a holding time of 6 seconds or more is given, the yarn will sway and become unstable to take off, and no particular improvement effect will be observed in terms of physical properties.

On the other hand, if the extrusion diameter of molten polyamide is used to obtain a monofilament larger than 40,000 deniers, the extrusion diameter is too large and the resulting monofilament has poor circularity, making it impractical.

In the method of the present invention, it is essential to hold the molten polyamide thus extruded from the spinning nozzle for a predetermined time and then rapidly cool it.

That is, in the method of the present invention, after extruding the molten polyamide from the spinning nozzle, rapid cooling is started within 0.6 to 1.2 seconds.

The molten polyamide extruded from this spinning nozzle (
The holding time of the molten polyamide yarn (hereinafter referred to as "molten polyamide yarn") is 0.6
It is necessary that the time is 1.2 seconds, and preferably 0.
It is 8 to 1.0 seconds.

If the holding time is shorter than the above range, the effect of the present invention cannot be expected; on the other hand, if the holding time is longer, the sagging of the molten polyamide yarn due to its own weight will increase, resulting in instability and non-uniformity of the filament. So I don't like it.

This holding time can be set by appropriately selecting the extrusion speed, take-up speed, distance between the spinning nozzle and the quenching device, etc.

For example, if normal monofilament manufacturing conditions are adopted using a spinning nozzle with a hole diameter of about 3, and the distance between the spinning nozzle and the quenching device is set to, for example, a monofilament of about 6000 denier at a take-up speed of 20 nl,
It is best to set it to about 20 to 30 cm, and also 20,000 cm.
When producing a monofilament of about denier at a take-up speed of 10 m/min, it is preferable to set it to about 10 to 15 crrL. The holding conditions other than the holding time may be the same as in normal monofilament production.

The operation is usually carried out in air or in a so-called inert gas such as nitrogen or carbon dioxide at a temperature of 60° C. or lower, and it is particularly advisable to operate in air at room temperature.

The molten polyamide yarn held under specified conditions as described above is then rapidly cooled.

The rapid cooling system uses water as a refrigerant and introduces it into water at room temperature or lower.
The cooled molten polyamide yarn is then subjected to a drawing treatment, but the method is not particularly limited, and any known method can be employed.

The first step is stretching 3 to 4 times in wet heat, e.g. steam or boiling water.
A method that combines stage stretching, second stage stretching in which the film is stretched 1.1 to 1.6 times by dry heat, and heat setting is suitable.

The polyamide monofilament obtained by the method of the present invention has markedly improved knot strength and transparency compared to the conventional monofilament that is not held for a specified period of time as in the method of the present invention, and is easy to manufacture, making it suitable for industrial use. This is extremely advantageous.

Hereinafter, the method of the present invention will be explained in more detail with reference to Examples, but the method of the present invention is not limited to the following Examples unless the gist thereof is exceeded.

In the Examples, "parts" indicate "parts by weight", and the knot strength and linear strength indicate values measured according to JISL1070.

In addition, the transparency of the product polyamide monofilament was measured using a photometric microscope (manufactured by Olympus Optical Co., Ltd., product name Multi Photometric Microscope MMSP), and the transmittance of visible light was measured.
Comparative measurement values are shown with completely transparent as 100% and completely opaque as θ%.

Examples 1, 2 and Comparative Example 1 ηrel obtained by copolymerizing 85 parts of ε-caglolactam and 15 parts of adipic acid hexamethylene diammonium salt
3.5 polyamide 6/66 copolymer pellets using a 30 mm extruder (manufactured by Tanabe Plastic Co., Ltd.).
It is extruded from a spinning nozzle with a hole diameter of 3 mm at 5°C, kept in air, then rapidly cooled, and then subjected to stretching treatment at a take-up speed of 20 m.
A polyamide monofilament of 6600 denier was produced at a speed of 6,600 denier per minute.

The polyamide was prepared when the space between the spinning nozzle and the water surface of the quenching device was 20°C air, the interval between them was as shown in Table 1 below, and the holding time was 1 second, 0.7 seconds, and 0.3 seconds. The linear strength, knot strength and transparency of the monofilament were measured and shown in Table 1 below.

In addition, as a rapid cooling device, it descends in water at 5℃ and ascends 1 m diagonally.
．． Using a 5 m water tank, the stretching conditions were: 1st stage: 3.5x in boiling water, 2nd stage: dry heat at 270'C, 1.5x, heat setting = 255°G, 0.95x.

Further, when the holding conditions were 1.3 seconds and 33 cIrL, the sample became unstable due to sagging, and collection was difficult.

Example 3 and Comparative Examples 2 and 3 Using the same polyamide pellets as in Example 1,
According to the method of Example 1, an 8800 denier polyamide monofilament was produced.

Measurements were made on polyamide monofilaments under the holding conditions shown in Table 2.

The results are shown in Table 2. In addition, the holding conditions were set to 1.3 seconds and 36c.
In the case of rrL; collection became difficult due to sagging.

Example 4 and Comparative Example 4 A 6600 denier polyamide monofilament was produced in the same manner as in Example 1 except that the polyamide 6/6 (copolymer) to be spun had ηre1 of 4.5.

Measurements were made on polyamide monofilaments under the holding conditions shown in Table 3.

The results are shown in Table 3. In addition, the holding conditions were set to 1.3 seconds and 36c.
In the case of rrL, it was difficult to take over because of the sag.

Examples 5, 6 and Comparative Example 5 The same polyamide pellets as in Example 1 were used, extruded from a spinning nozzle with a hole diameter of 4 mm, and the same procedure as in Example 1 was performed except that the quenching device and stretching conditions were changed as follows. A 22,000 denier polyamide monofilament was produced at a take-off speed of 10 m/min.

As a rapid cooling device, descend in 5℃ water and ascend 30m at an angle of 1.5
Stretching conditions were as follows: 1st stage stretching: 3.5x in boiling water, 2nd stage stretching: 1.2x dry heat at 275°C, heat setting = 260°G 0.95x. .

Measurements were made on polyamide monofilaments under the holding conditions shown in Table 4.

The results are shown in Table 4.

Claims (1)

[Scope of Claims] 1. In a method for producing a polyamide monofilament by extruding molten polyamide from a spinning nozzle, quenching it using water as a coolant, and then drawing it, the quenching process is performed by extruding the molten polyamide from a spinning nozzle and then quenching it using water as a coolant. 6-1.2
A method for producing polyamide monofilament characterized in that it is carried out in seconds. 2. The method for producing a polyamide monofilament according to claim 1, wherein the molten polyamide is made of a polyamide 6/66 copolymer. 3 Polyamide monofilament is 4000-4000
Claim 1 characterized in that it is 0 denier.
A method for producing a polyamide monofilament as described in Section 1.