JPS607721B2 - Manufacturing method of polyamide monofilament - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyamide monofilaments, particularly polyamide monofilaments with high knot strength.

Polyamide monofilaments (hereinafter simply referred to as monofilaments) are useful for fishing lines, fishing nets, and the like because of their characteristics such as toughness, transparency, and flexibility.

When used in these applications, the monofilament is tied into a knot, and the monofilament is almost always cut at the knot, so there has been a desire to improve the knot strength of the monofilament. Therefore, with the aim of manufacturing monofilament with improved knot strength, the present inventors solved the basic problem of knot strength, that is, the true factors that improve knot strength, and the ideal structure that can express these factors. We have already proposed one manufacturing method.

In this method, a polyamide monofilament that has been stretched in the first stage at a specific stretching ratio is subjected to relaxation heat treatment under specific conditions, and then subjected to a second stretching process under specific conditions.

Although the monofilament obtained by this method has the desired knot strength characteristics, it has slightly higher heat shrinkage characteristics, which causes deformation of the bobbin on which the monofilament is wound and an increase in the tension when pulling the monofilament from the bobbin. It was subsequently discovered that there was a problem with this occurring.

As a result of intensive research aimed at providing a method for manufacturing mo/filament that eliminates the above-mentioned problems, the inventors of the present invention found that the above-mentioned objective could be achieved by adding a specific operation to the already proposed method. I saw this and decided to release it.

That is, the purpose of the present invention is to place a polyamide monofilament with a diameter of 0.05 to 2 bars, which has been stretched in the first stage to 3 to 5 times the wind speed, into a pressure chamber supplied with saturated steam of lk9' or more. 0.05 at a stretching ratio of 0.70 to 1.0
Relaxation heat treatment for ~5 seconds, tB) Polyamide monofilament subjected to relaxation heat treatment in a gas of 200 to 800°C and/or a liquid of 150 to 265°C for a total of 0
．． The filament was coated with 1.
Applying a second stage of stretching of 1 to 2.8 degrees, and } While passing the polyamide monofilament that has undergone the second stage stretching through a gas of 150 to 700 qo for 0.05 to 5 seconds, the stretching ratio is 0.85-1. A polyamide monofilament having a surface layer having an amorphous molecular orientation degree of 0.5 or less and an average birefringence of 50×10 −3 or more can be obtained by carrying out a relaxation heat treatment using sound.

Hereinafter, the method of the present invention will be specifically explained in detail.

The monofilament used in the present invention has been stretched 3 to 5 times.

Polyhexamethylene adipamide (
At least one component is a homopolymer such as nylon 66), polyhexamethylene sebamide (nylon 610), polycapramide (nylon 6), polydodecamide (nylon 12), polyhexamethylene isophthalamide, or the above polyamide component. Copolymerized polyamides and mixed polyamides are selected. However, for fishing nets and lines in which the monofilament of the present invention is typically used, nylon 6,
In particular, a copolymer of nylon 6 is most preferably used. In the production of the monofilament of the present invention, various additives such as plasticizers, crystallization inhibitors, lubricants, pigments, dyes, light stabilizers, ultraviolet absorbers, antioxidants, etc. can be added to the polyamide.

Monofilament is produced by melting polyamide into paper yarn using a known method, passing it through a short air-cooling zone, and then rapidly cooling the spun monofilament using water, trichlene, n-hexane, etc. It begins by doing.

It is then usually sent to a direct drawing process where it is stretched 3 to 5 times. The atmosphere at that time is 100 to 400 oo gas, such as air, water vapor, or inert gas, or 50 to 400 oo
200% liquid such as water, glycerin, ethylene glycol, polyethylene glycol, silicone oil, mineral oil, vegetable oil such as medicinal oil, etc. is used. The reason why the stretching ratio is limited to the above range is that even if a monofilament drawn in a range other than the above range is subjected to subsequent processes, the monofilament will not have the properties aimed at in the present invention.

The monofilaments targeted by the present invention are limited to those having a specific fineness. This is because the above-mentioned relaxation green heat treatment forms a specific structure on the surface layer of the monofilament, and therefore the monofilament is treated under specific conditions. Even if it is applied, the conditions will be severe, and on the other hand, if it is extremely thick, the effect of the present invention will not be fully exhibited. The roughness of the monofilament used in the present invention is 0.05 to 2, preferably 0.0, based on the fineness of the monofilament subjected to moist heat treatment.
It is on the 8-1.2 side. Next, the stretched monofilament is subjected to a relaxing moist heat treatment.

The relaxation overflow treatment is carried out while the drawn monofilament is running in a pressure chamber to which saturated steam of 9' G or higher is supplied. The pressure chamber has an inlet where the monofilament enters and an outlet where the monofilament exits are sealed with a sealing mechanism consisting of a labyrinth, slit, or two pairs of rolls to prevent steam leakage as much as possible and maintain the steam pressure in the central processing section. It looks like this.
Inside the pressure chamber, the monofilament usually runs in a straight line and is controlled by two roll systems located at the inlet and outlet sides of the pressure chamber. The traveling speed varies depending on the length of the pressure chamber, steam pressure, etc., but the residence time in the pressure chamber is 0.05.
The time is set to 5 seconds, preferably 0.1 to 2 seconds.

If it is shorter than 0.09 sand, the surface layer of the monofilament will not form the desired structure, and if it is longer than 5 seconds,
High orientation cannot be achieved even if the inner layer portion is subsequently stretched in a high temperature atmosphere.

The moist heat treatment of the present invention is carried out in a relaxed state, and the relaxed state is controlled by the rotational speed of the two roll systems.

The ratio of the speed of the roll system on the exit side when the speed of the roll system on the inlet side is 1, that is, the stretching ratio is 0.70 to 1. Preferably, it is in the range of 0.75 to 0.95. If the moist heat treatment of the present invention is carried out under tension with a stretching ratio of more than 1, it becomes difficult to effectively form the desired structure exhibiting elastic properties in the surface layer portion. Furthermore, if the monofilament is subjected to relaxation heat treatment at a draw ratio of less than 0.70 (that is, if it is shrunk too much), the monofilament becomes white and devitrified, or the surface partially melts, making it impossible to obtain a transparent monofilament with high knot strength. In the case of a highly knotted monofilament, it is more effective to form the elasticity-expressing structure to the necessary thickness in the surface layer.

The appropriate thickness of the surface layer varies depending on the thickness of the monofilament, but the ratio to the radius of the monofilament cross section is
As the finished monofilament obtained by the present invention, 1/
50 to 1/25 bait degree, usually several microns to 15
Preferably, it is on the order of microns. The surface layer of the monofilament that has been subjected to the above-specified stretching and moist heat relaxation treatment of the present invention has a structure that exhibits elastic properties and is distinguished from the inner layer. It is designed to sufficiently withstand expansion and compression of the nodule surface.

However, due to the moist heat relaxation treatment, the molecular orientation in the inner layer portion is slightly lowered and the physical properties, especially the tensile strength, are reduced, so it is necessary to increase the molecular orientation to a level higher than that before the moist heat relaxation treatment.

Moreover, it is necessary to enhance the elastic property-expressing structure formed in the surface layer by this treatment without destroying it. Therefore, in the present invention, a second stage of stretching in a high temperature atmosphere is further performed following the green heat relaxation treatment. What is a high temperature atmosphere?20
0 to 800°C, preferably 250 to 600 qo of inert gas, and or 150 to 260 qo, preferably 16
0 to 240 liquids are passed through this high temperature atmosphere for a total of 0.05 to 5 seconds, preferably 0.1 to 2 seconds, at a stretching ratio of 1.1 to 2.3 sounds, preferably 1. 15~
Stretch the monofilament by a factor of 2.0. As an apparatus for stretching the inert gas medium, an air heating furnace is usually used, and methods of circulating air or efficiently heating with a far-infrared radiation heater or the like are also adopted.

As the heating liquid bath medium, glycerin, ethylene glycol, polyethylene glycol,
Use silicone oil, mineral oil, vegetable oil, etc. The stretching ratio is adjusted by two roll systems placed before and after the heating roller.

When the above-mentioned appropriate stretching conditions are adopted, the highly oriented layer changes into an elastic structure due to the surface treatment, so
It is noteworthy that it is now possible to stably spin yarn at a high magnification that was previously impossible.

After the second stage of stretching, a relaxation heat treatment is further performed in a high temperature atmosphere of a gaseous medium.

The processing conditions are such that the properties of the monofilament that has undergone the second drawing step are not impaired. That is, the monofilament after the second stage drawing is stretched in an inert gas atmosphere of 150 to 700 cm, preferably in a high temperature atmosphere of 200 to 600 cm, for 0.05 to 20 seconds at a drawing ratio of 0.85 to 1.0, preferably A winding condition of 0.9 to 0.95 is adopted. As a heat fixing device for a gaseous medium, an air heating furnace is usually used, and a method of effectively heating the material by circulating air or using a far-infrared ray fin heater or the like is also adopted. The stretching ratio is adjusted by two roll systems placed before and after the heating furnace. This operation
The monofilament is contracted while passing through a high-temperature atmosphere to remove stretching strain and reduce the shrinkage stress applied to the winding bobbin, so there is almost no deformation of the bobbin. As described above, the high knot strength monofilament of the present invention can be obtained by spinning, cooling, first drawing, thermal relaxation treatment, second drawing, and dry heat treatment under relaxed conditions. It is desirable that the operations be performed in conjunction with each other.

As a guideline for this operation, the degree of amorphous molecular orientation F in the surface layer, which is a characteristic of the monofilament finally obtained, is 0.5 or less, preferably 0.4 or less, and the average birefringence is 50 × 10 -3 or more, preferably 52×10-3 or more, should be selected. The monofilaments thus obtained have high tensile strength and high wet knot strength with good uniformity.

In addition, since this monofilament is highly oriented, it has a high tensile modulus in the fiber axis direction, but since the surface layer has a structure that exhibits elastic properties, it is flexible against bending, and is used in the knitting process and in actual use. It is extremely easy to handle when working with silk fabrics. Even when copolymerized polyamide is used, the boiling water shrinkage rate is generally low at 15% or less, and there is no deformation of the bobbin used for the weft in the knitting process, and there is no change in release tension when pulling out the monofilament. Therefore, since there is no change in the degree of amorphous molecular orientation F in the surface layer, there is no dyeing spot during the knitting process, and a knitted net with a more uniform mesh can be obtained, and there is no yarn breakage during knitting. Furthermore, transparency is maintained similar to monofilaments made by conventional methods. Such monofilaments are useful as fishing nets and fishing lines, but especially when made into fishing nets, flexible and highly strong fishing nets can be obtained, and they are preferred for use in fields such as gill netting.

Next, the effects of the present invention will be explained in detail using examples. The above-mentioned birefringence refers to the average birefringence including the surface layer and inner layer of the monofilament, and is a value measured by a conventional compensator method.

In addition, a monofilament with an amorphous molecular orientation of F' was treated in a 0.2% aqueous solution of a fluorescent agent for 2 hours, then washed with water and air-dried. The value was calculated using the following formula.

F=・-Harm L: Relative fluorescence intensity in the direction of the fiber axis bo: Relative fluorescence intensity in the direction perpendicular to the fiber axis The thickness of the surface layer where the fluorescent agent penetrates and the degree of amorphous molecular orientation is measured depends on the manufacturing history of the monofilament. There are about 5 different mountains.

The thickness of the surface layer where a low degree of amorphous molecular orientation has been achieved can be determined by etching the surface layer from the surface layer to the inner layer with a sulfuric acid/methanol solution and determining the amorphous molecular orientation of each sample. You can know. Wet knot strength is JISLI034-7 as initial load 1/3 weight/denier
It was measured by the method described in 8. Boiling water shrinkage rate is Showa 4 King 4
It was measured according to the method described in JFSLI027 as of April. Examples 1 to 4 and Comparative Examples 1 to 6 Polycapramide and polyhexamethylene adipamide copolymer with sulfuric acid relative viscosity of 3.4 Nylon 6/66 (95/5 molar ratio) copolymer chip with ethylene bisstearylamide 0
．． 2% by weight was mixed and 2% by weight was mixed using an extruder type spinning machine.
It was made into a melt grade yarn at 65 qo.

Water at 5°C was used for the cooling bath. The first-stage stretching, second-stage moist heat treatment, and third-stage stretching were performed under the following conditions.

1st stage stretching temperature: 9zo○ Stretching ratio: 4. Pione 2nd stage wet heat treatment Steam pressure: 24k9/○ Stretching ratio: 0.84 times Time (seconds): 0.8 Existing sand 3rd stage stretching temperature: 400q0 Stretching ratio: 1. Needle sound time (seconds): 1.4 Yarn was produced by changing the stretching (relaxation heat treatment) conditions in the fourth stage of parent sand, and the properties of the obtained monofilaments were compared.

Table 1 shows the heat treatment conditions, and Table 2 shows the properties of the corresponding monofilaments.

In Comparative Example 3 of Table 1, the relaxation rate was too high, resulting in sagging and partial fusion.

Furthermore, in Comparative Example 5, the temperature was too high, causing fusion and yarn breakage. Table 2 Monofilaments obtained without passing through the relaxation heat treatment step and monofilaments obtained by relaxation heat treatment under conditions other than the above conditions have a large shrinkage rate, and therefore the winding bobbin is largely deformed.

Claims (1)

[Scope of Claims] 1 (A) Diameter 0 which has been stretched 3 to 5 times in the first stage
．． 05~2mm polyamide monofilament, 1k
g/cm^2G or more is introduced into a pressure chamber supplied with saturated steam, and the stretching ratio is 0.05 to 5 at a stretching ratio of 0.70 to 1.0.
(B) The relaxation heat treated polyamide monofilament is heated in a gas at 200 to 800°C and/or in a liquid at 150 to 265°C for a total of 0.05 seconds.
1.1-2 to the filament while passing for ~5 seconds.
．． (C) The polyamide monofilament subjected to the second stage stretching is subjected to a 0.05 to 5 times stretching in an inert gas at 150 to 700°C.
A relaxation heat treatment is performed at a stretching ratio of 0.85 to 1.0 times while passing the film for 5 seconds.The degree of amorphous molecular orientation in the surface layer part is 0.5 or less, and the average birefringence is 50 x 10^-^3 or more. A method for producing a polyamide monofilament having a molecular orientation of.