JPS645492Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Field of Industrial Application) The present invention relates to a fishing net made of a polyamide resin that has excellent knot strength and is particularly suitable for gill net fishing nets. (Prior Art) It is well known that fishing nets made of polyamide resin are widely used because of their excellent strength, transparency, flexibility, and the like. In particular, monofilaments made of polyamide resin have better transparency of the net threads, better water drainage in terms of operability, and moderate stiffness than multifilaments, and have a good net structure, making it easier to catch fish. Due to their excellent efficiency, monofilament fishing nets are commonly used in other gillnet fields, including salmon and trout fishing. Monofilament fishing nets used in this gillnet field range from size 0.5 (110 denier) to size 30
(6,600 denier) or a thin monofilament of a specified number, for example, a monotwine fishing net made by twisting three monofilaments of size 1.5 or 3 to 5, and teeth
Fishing nets are mainly knitted using 4 to 24 twisted yarns of size 0.5 to size 2 monofilament. As described above, fishing nets using monofilament have knots, and in these knots, the monofilaments are compressed against each other, and it is thought that compression from the sides, that is, lateral pressure is applied.
The knot has a disadvantage in that it is less strong than the mesh leg and is more likely to break during use. Therefore, even if monofilaments have excellent properties as described above, there is still a need for improved knot strength. A mesh with improved knot strength and knot fixation properties has been proposed in Japanese Utility Model Publication No. 15823/1983. This device consists of a monofilament that has a cross-sectional shape of a polygon larger than a triangle with the sides concave inward.The fins collapse and bite deeply, so the knots do not loosen or shift, but they deform into yarn. It is easy to cause a decrease in strength due to the occurrence of cracks, and since it is composed of a single monofilament, it has poor flexibility, and because it has fins at each vertex of a triangular or larger polygon, it reflects a lot of light. However, it had the disadvantage of poor fishing performance. Furthermore, for polyolefin or polyvinylidene chloride, adhesive threads in which filaments are fused are known.
A manufacturing method thereof is proposed in Japanese Patent Publication No. 48-32981. However, the former is an adhesive thread shown in Fig. 1 A and B in which multiple polyolefin monofilaments are weakly bonded, and these are separated and used as a monofilament.
The latter is a multifilament in which a plurality of single filaments of polyvinylidene chloride are fused together to achieve good convergence, and is essentially different from the connecting yarn of the present invention. (Problems to be Solved by the Invention) The problems to be solved by the invention are to provide a fishing net for gillnets that has high knot strength, has good net structure of the net thread, and has low light reflection. It is in. (Means and effects for solving the problem) In order to meet the demands of the market, the inventors of the present invention have conducted various studies and found that a fishing net knitted using a connecting thread of a specific shape has excellent knot strength. The present inventors discovered that the fishing net of the present invention is suitable for gill net fishing nets. That is, the present invention is a connecting thread in which two monofilaments B and C are fused in the length direction of the outer circumference of one monofilament A, and the diameters of monofilaments B and C are the diameter of monofilament A. , the two monofilaments B and C are separated from each other, and the connection angle θ formed by the three monofilaments A, B, and C defined in the text is 60°<θ≦ The gist of this invention is a fishing net made of polyamide resin, which is characterized by being made of connecting threads having an angle of 120°. Here, the connection angle θ formed by the three monofilaments A, B, and C is expressed as O _B O _A O _C , and O _A ,
O _B and O _C are the centers of three monofilaments A, B, and C. The present invention will be further explained in detail below. The polyamide connecting yarn used in the present invention is a connecting yarn in which two monofilaments B and C are fused to each other in the length direction of the outer periphery of one monofilament A. If all of the fibers are connected, the cooling balance during spinning and the heat receiving effect during stretching will be poor, making it impossible to obtain high knot strength. Furthermore, if the diameters of the individual threads of the connecting yarn are significantly different, the orientation will be different due to the difference in cooling during filament production, making it difficult to obtain a uniform connecting thread, and it is necessary that the diameters of the single yarns are approximately the same. In this case, if the ratio of the diameters of monofilaments B and C is set to 0.8 to 1.2, there will be no problem in terms of yarn uniformity and bending stress. Exceeding the above range is unfavorable from the viewpoint of bending stress and yarn uniformity, and the knotting strength of such a connecting yarn will not be high. FIG. 1C is a sectional view showing an example of a connecting thread according to the present invention. In the illustrated example, one monofilament A is connected to monofilaments B and C having the same diameter.
This shows the case where they are connected separately. Next, in addition to the above-mentioned conditions, the connecting thread of the present invention must have a connecting angle θ formed by the three monofilaments A, B, and C in the range of 60°<θ≦120°. This connection angle θ is an important requirement in the present invention, and the inventors of the present invention discovered that elliptical monofilaments were often used in the past when there was no good sealing resin when knitting monofilament fishing nets. Later, with the development of resin processing, the cross-sectional shape of the filament was required to be close to a perfect circle, and the shape of the filament was similar to that of three-strand monotwin or multi-strand monofilament. As a result, we conducted various experiments and found that the range of connection angle θ of 60°<θ≦120° is optimal for the gillnet fishing net of the present invention. In other words, if the connection angle θ is 60° or less, the first
It tends to become hollow fibers like the conventional adhesive yarn shown in Figure B, and the knot strength becomes low, and if the connection angle θ exceeds 120°, it becomes similar to the conventional adhesive yarn shown in Figure 1 A, and the bundling property decreases. This is undesirable because it causes a decrease in the amount of fish caught due to increased light reflection. The connecting thread of the present invention is manufactured by the manufacturing process shown in FIG. That is, the polyamide resin melted from the melt extrusion device 1 is extruded through a nozzle having a nozzle hole (described later), and is spun into an undrawn connected yarn in which three monofilaments are fused together. After being cooled in
Multi-stage stretching is performed in the stretching device 3, and then the heat treatment device 4
After being heat-treated, it is rolled up by a winding device 5. Figure 3 shows the shape of the nozzle hole used when manufacturing the connecting thread, which is a shape in which one circular hole and two other circular holes are connected by slits at a predetermined angle. It shows. The dimension of this nozzle hole, that is, the diameter of the circular hole,
The slit width W, length L, etc. can be changed as appropriate depending on the intended use of the obtained fishing net. In this case, it is preferable that the slit has a wide width W and a short length L within a range that does not significantly impair the circular shape and balance of each monofilament. For example, the slit width W0.1 mm and the length L0. By using a multi-hole group nozzle having a nozzle hole having a shape of 15 mm and a circular hole diameter of 0.8 mm, a connecting line suitable for a fishing net for gillnets can be obtained. In addition, in the nozzle hole of the above shape, without drilling a slit connecting the circular holes, by appropriately selecting the interval between the circular holes, it is possible to create a nozzle directly below the nozzle from several mm to several centimeters.
Although it is possible to fuse the slits between the slits, it is preferable to form the slits as described above because the shape of the connecting threads obtained is more stable and the connecting threads of good quality can be obtained. The connecting yarn obtained as described above is then used as it is or by aligning a plurality of yarns to form a net yarn without going through the twisting step, and this is knitted according to a known method to form the fishing net of the present invention. . The thus knitted fishing net of the present invention is suitable for fishing nets, especially gillnets. The polyamide in the present invention is a polymer having an amide bond in its molecular chain, and includes homopolymers, copolymers, and blend polymers such as nylon 6, nylon 66, nylon 610, and nylon 12. In the fishing net of the present invention having the above-mentioned configuration, the connecting thread used is a connecting thread in which two monofilaments are fused in the length direction of the outer circumference of one monofilament, and the two monofilaments are The monofilaments are separated from each other, the cross-sectional shape of each monofilament is a perfect circle or close to a perfect circle, and their diameters are approximately the same, and the connection angle θ formed by the three monofilaments is 60° < θ≦
Since the net is knitted from a specified connection angle in the range of 120°, it is possible to obtain a fishing net with superior knot strength compared to the conventional three-strand monotwine fishing net. In addition, the connecting thread used in the fishing net of the present invention has two monofilaments fused to one monofilament separated from each other, so it is compared to the conventional adhesive thread in which three monofilaments are glued together. During production, the cooling balance during spinning and the heat receiving effect during stretching are good, and the production conditions are also advantageous, allowing fishing nets of stable quality to be obtained. (Example) Hereinafter, the present invention will be explained based on an example. Implementation 1 Melt nylon 6 chips and spin them using a nozzle with a nozzle hole shaped as shown in Figure 3 (circular hole 0.8 mm, slit width 0.1 mm, slit length 0.15 mm),
After being solidified by water cooling, it was drawn and heat treated to make three connected yarns with finenesses of 9, 12, and 15, respectively.
The cross section of this connecting thread has the shape shown in Fig. 1C,
The connection angle was approximately 90°. On the other hand, for comparison, we manufactured three-strand monotwine with monofilament thicknesses of No. 3, No. 4, and No. 5, respectively, and measured the dry and wet knot strength of these, and the results shown in Table 1 were obtained. Obtained.

[Table] From Table 1, it is clear that all three connected yarns of the present invention are superior to the corresponding three-strand monotwine in terms of dry and wet knot strength. Example 2 Nylon 6 (Experiment No. 1), blend polymer of nylon 6 and (copolymer of nylon 6 and nylon 66) (experiment No. 2), nylon 6 and nylon 66
Three types of chips of the copolymer (Experiment No. 3) were melted and a No. 4.5 connecting thread of the present invention was produced using a nozzle hole as shown in FIG. These connecting threads had a cross-sectional shape as shown in FIG. 1C, and the connecting angle was approximately 90°. On the other hand, for comparison, we manufactured connecting yarns with conventional shapes as shown in Figure 1 A and B, and measured the dry and wet knot strength, dry and wet Young's modulus, and dry and wet bending stress of these connecting yarns. As a result, the results shown in Table 2 were obtained. In Table 2 above, “knot strength” is JIS-
Measured according to L1034. "Young's modulus" is JIS-
Measured according to 1073. "Bending stress" is sample length 3
cm, the distance between the supporting points is 2 cm, a load is applied to the center of the sample, and the value is expressed as the load when the sample is bent by 1 mm. As is clear from Table 2, the connecting yarn of the present invention has both dry and wet knot strength of about 10 to 20 for any polymer, compared to the conventional connecting yarn in which three monofilaments are fused together. % higher knot strength. In addition, in the case of conventional connecting threads with a connecting angle θ of 180°, light reflection is large and the knot strength is about 10% compared to the present invention.

[Table] The level was low. In addition, the connecting yarns of the present invention are excellent in terms of flexibility, Young's modulus, and bending stress results, and sensory tests have also been conducted on the texture of nets knitted using the connecting yarns of the present invention. As a result, the connecting yarn of the present invention was found to be good. Next, the connecting yarn of the present invention from Experiment No. 1 was made into a net yarn as it was without twisting, and this net yarn was used to make a net fabric with a mesh size of 116 mm with the double frog knot shown in Figure 4. I made a gill net. On the other hand, for comparison, gill nets with similar nettings were made using three-strand monotwine of No. 1.5 monofilament and a net thread of one No. 5 monofilament. The results of measuring the physical properties of these fabrics were as shown in Table 3. In Table 3, "hooking strength", "hooking elongation" and "net fabric strength" were all measured according to JIS-L1043. The "reversal rate" is a measure of the misalignment of the knots of the mesh fabric, and is calculated from the following formula. Reversal rate (%) = Strength when turning knots with strong net hooking / Strength when cutting knots with strong net hooking × 100

[Table] As is clear from Table 3, the net fabric made of the connecting yarn of the present invention has a dry and wet hooking strength of 1.5 No. 3.
Approximately 10 times larger than that of net fabric made of real twisted monotwine
%, and was almost equivalent to that of a net fabric made of No. 5 monofilament, which is thicker than the connecting yarn of the present invention. In addition, regarding the strength of the mesh fabric, the fabric of the present invention is about 10% higher than both the fabric made of No. 1.5 three-strand mono twine and the fabric made of No. 5 monofilament.
It was expensive. Furthermore, the reversal rate of the fabric of the present invention was 15% higher when dry and 10% higher when wet than other fabrics made of No. 1.5 3-strand mono twine. (Effects of the invention) The fishing net of the invention is made of connected yarns with the above structure, and has high knotting strength in dry and wet conditions, and has good convergence, so it is possible to knit the net without going through the twisting process. It also has the advantage of good flexibility and good net formation, and can be widely used in fishing nets, especially gill nets.

[Brief explanation of the drawing]

Figures 1A and 1B are cross-sectional views showing an example of a conventional adhesive thread, Figure 1C is a cross-sectional view showing an example of a connecting thread in the present invention, and Figure 2 is a manufacturing process of the connecting thread in the present invention. FIG. 3 is a plan view showing an example of a nozzle hole used in manufacturing the connecting thread of the present invention, and FIG. 4 is a plan view showing a frog knot. A, B, C...monofilament, O _A , O _B ,
O _C ... center of monofilament, θ ... connection angle,
W...Width of the slit, L...Length of the slit, 1
... Melt extrusion device, 2 ... Cooling device, 3 ... Stretching device, 4 ... Heat treatment device, 5 ... Winding device.

Claims (1)

[Scope of utility model registration request] It is a connecting thread in which two monofilaments B and C are fused in the length direction of the outer circumference of one monofilament A, and the diameters of monofilaments B and C are approximately the same as the diameter of monofilament A. Moreover, the two monofilaments B and C are separated from each other, and the connection angle θ formed by the three monofilaments A, B, and C as defined in the text is 60°<θ≦120°. A fishing net made of polyamide resin, characterized in that it is made by making a net.