JP2021188244A - Monofilament for fishing net - Google Patents

Abstract

To provide a monofilament for a fishing net that is composed of a polyamide-based resin, in which a strength required by the fishing net is maintained while maintaining flexibility etc. that is an advantage of the polyamide-based resin, and stretching is hard to be caused when an external force is applied or when the material absorbs water, and dimensional stability is provided.SOLUTION: There is provided a sheath core type composite monofilament, in which the filament is composed of a polyester-based resin at the core and a polyamide-based resin at the sheath, a proportion of the polyamide-based resin in the filament is 70 to 90 vol.%, and a cross-sectional area of a cross section of the composite filament is 7.8×10-3 mm2 to 5.0×10-1 mm2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a monofilament constituting a fishing net.

The performance required for fishing nets includes high strength, suppleness, easy dyeing, etc., and monofilaments mainly made of polyamide resin are used. Among the polyamide resins, polyamide 6 in particular is used. Resins and polyamide 6/66 copolymer resins are used. Fishing nets made of polyamide resin are excellent in suppleness, so the nets are not bulky on board and can be piled up in large numbers.

On the other hand, fixed fishing nets such as fixed nets are often made of polyester resin, which has good dimensional stability and a high specific density so that it will not be shaken by the wave wind even a little. Furthermore, the polyester resin has been improved. Those having an improved specific gravity, or those having a large specific gravity in combination with a fluoromonofilament and a polyester monofilament are used.

The above-mentioned net made of polyamide resin is a filament that constitutes the net by its own weight, resistance of water, weight loaded on the catch, external force due to friction with the seabed, and external force such as tension at the time of lifting. It is easy to stretch, the mesh opens, and the caught fish may fall out. In particular, in the case of a bottom tow net, in addition to friction with the seabed, the tension generated during tension may cause the net to stretch more than necessary, leading to net breakage. Since the fishing net comes into contact with the ship's edge during withdrawal, this contact friction may also cause the net to break.

In a net made of a polyamide resin, it is an object to improve both suppleness and strength, and a fishing net in which an aromatic group-containing polyamide type unit is contained in the polyamide resin is disclosed.

Japanese Unexamined Patent Publication No. 2004-250556

According to the present invention, in a fishing net made of a polyamide resin, the strength required by the fishing net is maintained while maintaining the suppleness which is an advantage of the polyamide resin, and when an external force is applied. It is an object of the present invention to provide a monofilament for fishing nets which is hard to stretch when water is absorbed and has dimensional stability.

The present inventors have focused on a phenomenon in which a polyamide monofilament changes in size when an external force is applied.

Polyamide fibers are generally considered to have good wear resistance and are preferably used for bags and the like. The bag is made of a woven fabric or the like, and the abrasion resistance in this case is an evaluation of the abrasion resistance when the surface of the fabric rubs against other objects on the surface, and an external force is applied to the fibers in the fiber axis direction. It is not an evaluation of the wear resistance in the state of being woven.

A filament made of polyamide tends to stretch easily with a low load when an external force is applied in the axial direction of the filament, and to stretch even more easily when it absorbs moisture. Then, when elongation occurs, the elongated portion is more likely to be damaged due to the smaller filament diameter. When used as a fishing net, the net is pulled more strongly than the friction on the surface of the net, so that it often rubs against other objects while an external force is applied in the axial direction of the filament constituting the net. Therefore, the present inventors have wondered if it is possible to provide a monofilament for fishing nets that can maintain durability when an external force is applied in the axial direction of the filament and friction occurs.

Then, the present inventors have studied to achieve the above-mentioned problems. As a result, by compounding the polyester resin in the core of the filament composed of the polyamide resin at a specific ratio, the region of the polyester resin in the core expands or deforms when a load is applied to the filament. We have found that it plays a role of suppressing and arrived at the present invention.

That is, the present invention is a core-sheath type composite monofilament, in which the core portion is composed of a polyester-based resin and the sheath portion is composed of a polyamide-based resin, and the ratio of the polyamide-based resin to the filament is 70 to 90 volumes. %, And the cross-sectional area of the cross section of the composite filament is 7.8 × 10 ^-3 mm ^{2 to} 5.0 × 10 ^-1 mm ² .

Hereinafter, the present invention will be described in detail.

The monofilament for fishing nets of the present invention is a composite of a polyamide resin and a polyester resin in a core-sheath type, and the core portion is made of a polyester resin and the sheath portion is made of a polyamide resin. In the core-sheath type, the number of cores may be one or may be as many as 2 to 5 cores, but it is preferably one.

The cross-sectional shape of the monofilament is not particularly limited, such as a circular shape, an elliptical shape, or a polygonal shape, but a circular cross-sectional shape is preferable from the viewpoint of mechanical properties and versatility. Further, the cross-sectional shape of the core portion is not limited to a circular shape but may be a deformed shape.

The polyamide resin constituting the sheath portion is not particularly limited as long as it has an amide group in the molecule. For example, nylon 6, nylon 66, nylon 69, nylon 46, nylon 610, nylon 1010, nylon 11 , Nylon 12, Nylon 6T, Nylon 9T, Polymethoxylen adipamide, and those obtained by copolymerizing or blending these components.

The polyester resin constituting the core portion is not particularly limited as long as it has an ester bond in the molecule. Examples of the aromatic polyester include polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate and the like. Further, examples of the aliphatic polyester include polylactic acid, polybutylene succinate, polycaprolactone and the like. Further, as long as the object in the present invention is not impaired, the above-mentioned polyesters may be blended with each other, or the above-mentioned polyesters may be blended with polyesters obtained by copolymerizing other components. Examples of other components that can be copolymerized include isophthalic acid, naphthalenedicarboxylic acid, 5-sophthalic isophthalic acid, phthalic acid anhydride, sebacic acid, adipic acid, succinic acid and the like as dicarboxylic acids, and succinic acid as a diol component. Examples thereof include ethanediol, propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, cyclohexanedimethanol and the like. Further, a polyester-based thermoplastic elastomer or a polyester-based thermoplastic elastomer composition may be added to the above-mentioned polyester. The amount to be added is at most 10% by mass in the core portion, and 2 to 8% by mass is preferable. By containing the polyester-based thermoplastic elastomer or the polyester-based thermoplastic elastomer composition in the polyester of the core portion, the bondability of the interface between the sheath portion made of the polyamide-based resin and the core portion made of the polyester-based resin is improved, and the fiber It is preferable because it is difficult to stretch when an external force is applied in the axial direction.

As the relative viscosity of the polyester resin, the relative viscosity is preferably 1.4 or more, more preferably 1.5 or more, in order to have the desired mechanical properties. If the relative viscosity is high, the mechanical properties tend to be high, but the upper limit of the relative viscosity is preferably about 1.65 in consideration of handleability and the like. The relative viscosity of the polyester was measured at a temperature of 20 ° C. using a Ubbelohde viscometer using an equal mass mixed solution of phenol / ethane tetrachloride having a concentration of 0.5% as a solvent.

Further, as long as the object of the present invention can be achieved, various additives may be contained in the polyamide resin or the polyester resin constituting the monofilament, if necessary, for example, a crystal nucleating agent. Mattes, pigments, light resistant agents, weather resistant agents, antioxidants, antibacterial agents, fragrances, heat stabilizers, plasticizers, dyes, surfactants, surface modifiers, various inorganic and organic electrolytes, fine powders, difficult Examples thereof include additives such as flame retardants and compatibilizers.

The monofilament for fishing nets of the present invention is mainly composed of a polyamide-based resin, and is characterized in that a polyester-based resin is arranged on the core of the monofilament composed of the polyamide-based resin. Since the monofilament is mainly composed of a polyamide-based resin, it has excellent suppleness and good dyeability as compared with, for example, a monofilament composed of only a polyester-based resin. Then, by arranging the polyester resin continuously in the filament axial direction on the core portion of the monofilament mainly composed of such a polyamide resin, when an external force is applied to the monofilament, or when an external force is applied to the monofilament, the polyamide resin is used. When the resin is subjected to its own weight due to moisture absorption or water absorption due to the characteristics of the resin, the polyester resin has excellent dimensional stability, so that the shape is maintained in the axial direction of the monofilament and the deformation due to the elongation of the monofilament itself is suppressed. Further, since deformation due to elongation is unlikely to occur, thinning (deformation) in the filament axial direction is suppressed, and damage due to wear is less likely to occur. On the other hand, in the case of a monofilament made of only a polyamide resin, it is easily deformed in the axial direction when an external force is applied, the deformed part is thinned, and the stress due to wear etc. is concentrated on the thinned part. However, the damage progresses at an accelerated rate, and the damage easily breaks.

In the present invention, the proportion of the polyamide resin in the monofilament is 70 to 90% by volume in order to exert the above-mentioned effects. By setting the proportion of the polyamide resin in the monofilament to 70% by volume or more, the suppleness is excellent, the dyeability is good, and the practical strength for fishing nets is sufficiently exhibited. On the other hand, by setting the proportion of the polyamide resin to 90% by volume or less, the dimensional stability and wear resistance of the polyester resin are dramatically improved. More preferably, the proportion of the polyamide resin in the monofilament is 80 to 90% by volume.

The cross-sectional area of the monofilament for fishing nets of the present invention when cut at right angles to the filament axial direction is 7.8 × 10 ^-3 mm ^{2 to} 5.0 × 10 ^-1 mm ² . By setting the cross-sectional area to 7.8 × 10 ^-3 mm ² or more, fluff is less likely to occur due to friction caused by contact with the seabed or ship edge. On the other hand, when the cross-sectional area is 5.0 × 10 ^-1 mm ² or less, the strength per single yarn can be effectively exhibited and the suppleness of the yarn can be maintained, so that the workability at the time of knitting can be improved. It is good. Here, for the cross-sectional area, a photograph is taken using a micro scoop, and the area is calculated from the photograph.

The monofilament for fishing nets of the present invention can be obtained by the following method. First, using a core-sheath type composite nozzle, a polyamide-based resin is placed on the sheath, a polyester-based resin is placed on the core, weighed so that the ratio of the polyamide-based resin is 70 to 90% by volume, and melt-spun. do. Next, the yarn obtained by melt spinning is cooled in a water bath, and once wound as unstretched yarn or continuously drawn without being wound. The stretching ratio for stretching is 4 to 8 times, and heat stretching is performed. As a heating means for heat stretching, heat stretching is performed in a hot water bath or heat stretching is performed using a heating roller. After the heat stretching, the winding operation is continuously performed to obtain the desired monofilament.

Using the obtained monofilament, a fishing net may be obtained by adopting a desired structure by a knitting machine. When applied to a knitting machine, it may be used in the form of a monofilament yarn composed of one yarn, or may be used in the form of a bundle of a plurality of monofilaments.

Since the monofilament for fishing nets of the present invention is excellent in dimensional stability and wear resistance, it can be particularly effectively applied as a non-fixed fishing net such as a bottom tow net or a gill net.

The monofilament for fishing nets of the present invention has excellent suppleness and good dyeability, sufficiently exhibits practical strength as a fishing net, and has dramatically improved dimensional stability and abrasion resistance. It is possible to provide a fishing net having excellent properties and wear resistance.

The schematic perspective view of the bending type wear test for evaluating the wear resistance is shown.

Next, the present invention will be described based on examples. The present invention is not limited to the examples below. The method for measuring the characteristic values and the like in the examples is as follows.
(1) Tensile strength (N) and elongation (%)
Since the monofilament is usually wound, the required amount of unwound monofilament was allowed to stand at room temperature for 24 hours or more, and the maximum strength and breaking elongation were measured with a constant-speed elongation type tensile tester. The conditions of the tensile test were that the tensile speed was 300 mm / min, the gripping interval was 250 mm, and the average values measured at n = 5 were the tensile strength (N) and the elongation (%).

(2) Knot strength The strength at the time of cutting was measured using a constant-speed extension type tensile tester according to JIS L 1013. Nodules were formed for both a) and b) knots described in JIS L 1013, the tensile speed was 300 mm / min, the gripping interval was 250 mm, and the knots of a) b) were measured at n = 5, respectively. , The average value was taken as the nodule strength (N).

(3) Abrasion resistance (bending type abrasion test)
As the wear body, sandpaper # 1500 is attached to the side surface of a metal round bar with a diameter of 20 mm, and the sample (monofilament) is brought into contact with the wear body at an angle of 90 degrees, and a predetermined load is applied to one end of the sample. The sample was reciprocally rubbed at a stroke width of 120 mm and a stroke speed of 35 times / minute, and the number of reciprocating times until the sample broke was measured. The sample was measured at n = 3, and the average value of the obtained number of times was taken as the number of times of wear resistance. The predetermined load was 3.0 kg per sample cross-sectional area (mm ^2). For example, when the cross section is circular and the wire diameter is 0.2 mm, a load of 94 g is applied.
For the evaluation of wet wear, a wear test was performed using a sample immersed in water at room temperature for 24 hours or longer. After the wear test was started, no water was added to the sample.

Note that FIG. 1 shows a schematic perspective view of a bending type wear test for measuring wear resistance.

Example 1
As the polyamide resin to be arranged in the sheath, 90% by mass of polyamide 6 resin (manufactured by Unitika Co., Ltd., trade name A1030BRF) and 10% by mass of nylon 6.66 copolymer resin (manufactured by DSM, trade name "Novamid 2030J"). I prepared a blend of and.
As a polyester-based resin to be arranged on the core, a polyethylene terephthalate resin (manufactured by Unitika, trade name “NEH2070”) with a relative viscosity ηrel = 1.55 was prepared.

Weighed so that polyamide-based resin (sheath) / polyester-based resin (core) = 80/20 (volume ratio), and the polymer temperature was 280 ° C. from a 2.0 mmφ x 9H spinneret to a spinning speed of 16 m / It was melt-spun under the condition of minutes (the number of cores is one). The melt-spun yarn is cooled in a water bath at 30 ° C. at a speed of 16 m / min, then stretched 3.5 times in a warm bath at 95 ° C. without winding (first-stage stretching), and then wound. Without taking, it was stretched at 1.4 times in a dry heat atmosphere at 175 ° C. (second stage stretching), then relaxed and then wound (total stretching ratio 4.9 times). The obtained core-sheath type composite monofilament has a yarn diameter of 0.462 mm ^{, a cross-sectional area of 1.68 × 10 -1 mm 2} (fineness 1997 dtex), a tensile strength of 5.3 cN / dtex, an elongation of 22.0%, and a knot strength. It was 3.1 cN / dtex. Table 1 shows the evaluation results of wear resistance.

Comparative Example 1
As a polyamide resin, a blend of 90% by mass of a polyamide 6 resin (manufactured by Unitika Co., Ltd., trade name A1030BRF) and 10% by mass of a nylon 6.66 copolymer resin (manufactured by DSM, trade name "Novamid 2030J"). Prepared.

Then, the above-mentioned blended polyamide-based resin was melt-spun at a spinning speed of 26 m / min from a spinneret having a polymer temperature of 245 ° C. and a diameter of 2.5 mmφ × 24H. The melt-spun yarn is cooled in a water bath at 10 ° C. at a speed of 26 m / min, then stretched 3.4 times in a warm bath at 90 ° C. without winding (first-stage stretching), and then wound. Without taking, it was stretched at 1.4 times in a dry heat atmosphere at 165 ° C. (second stage stretching), then relaxed and then wound (total stretching ratio 4.6 times). The obtained monofilament consisting only of polyamide has a yarn diameter of 0.459 mm ^{, a cross-sectional area of 1.65 × 10 -1 mm 2} (fineness of 1717 dtex), a tensile strength of 6.1 cN / dtex, an elongation of 19.2%, and a knot strength. It was 3.9 cN / dtex. Table 1 shows the evaluation results of wear resistance.

Example 2
As the polyamide resin to be arranged in the sheath, 75% by mass of nylon 6.66 copolymer resin (manufactured by DSM, trade name "Novamid 2330J") and nylon 6.66 copolymer resin (manufactured by DSM, trade name "Novamid 2030J") A blend of 25% by mass was prepared.
As a polyester-based resin to be arranged on the core, a polyethylene terephthalate resin (manufactured by Unitika, trade name “NEH2070”) with a relative viscosity ηrel = 1.55 was prepared.

Weighed so that the polyamide resin (sheath part) / polyester resin (core part) = 70/30 (volume ratio), and the polymer temperature was 270 ° C. from a 1.8 mmφ × 6H spinneret to a spinning speed of 17. Melt spinning was performed under the condition of 4 m / min (the number of cores is one). The melt-spun yarn was cooled in a water bath at 10 ° C. at a speed of 17.4 m / min and then stretched 3.8 times in a warm bath at 85 ° C. without winding (first-stage stretching). Then, without winding, it was stretched at 1.53 times in a dry heat atmosphere at 180 ° C. (second stage stretching), then relaxed and then wound (total stretching ratio 5.8 times). The resulting core-sheath composite monofilament is, thread diameter 0.203 mm, the cross-sectional area 3.23 × ¹⁰ -2 mm ^2, a tensile strength of 6.8cN / dtex, elongation 13.8%, knot strength 4.2CN / It was dtex. In Example 2, the tensile strength, the elongation, and the nodule strength were measured in a state where six monofilaments were aligned (fineness 2600dtex / 6f). Table 1 shows the evaluation results of wear resistance.

Example 3
As the resin to be placed on the core, polyethylene terephthalate resin (manufactured by Unitica, trade name "NEH2070") with a relative viscosity ηrel = 1.55 of 95% by mass, and a polyester-based thermoplastic elastomer composition (manufactured by Mitsubishi Chemical Co., Ltd., trade name "Modic") A core-sheath composite monofilament was obtained in the same manner as in Example 2 except that a blend of GQ331 ”) with 5% by mass was used. The resulting core-sheath composite monofilament is, thread diameter 0.198 mm, the cross-sectional area 3.07 × ¹⁰ -2 mm ^2, a tensile strength of 7.4cN / dtex, elongation 14.0%, knot strength 4.4CN / It was dtex. In Example 3, the tensile strength, the elongation, and the knot strength were measured in a state where six monofilaments were aligned (fineness 2339 dtex / 6f). Table 1 shows the evaluation results of wear resistance.

Comparative Example 2
As the polyamide resin, 75% by mass of nylon 6.66 copolymer resin (manufactured by DSM, trade name "Novamid 2330J") and 25% by mass of nylon 6.66 copolymer resin (manufactured by DSM, trade name "Novamid 2030J"). I prepared a blend of.

Then, melt spinning was performed at a polymer temperature of 255 ° C. from a spinneret of 0.8 mmφ × 54H at a spinning speed of 25 m / min. The melt-spun yarn is cooled in a water bath at 12 ° C. at a speed of 25 m / min, then stretched 3.5 times in a warm bath at 95 ° C. without winding (first-stage stretching), and then wound. Without taking, it was stretched 1.7 times in a dry heat atmosphere at 215 ° C. (second stage stretching), then relaxed and then wound (total stretching ratio 6.0 times). The fibers obtained, yarn diameter 0.200 mm, the cross-sectional area 3.14 × ¹⁰ -2 mm ^2, a tensile strength of 8.6cN / dtex, elongation 20.9 percent, knot strength 4.7cN / dtex met rice field. In Comparative Example 2, the tensile strength, the elongation, and the knot strength were measured in a state where six monofilaments were aligned (fineness 2355 dtex / 6f). Table 1 shows the evaluation results of wear resistance.

The monofilaments of Examples 1 to 3 had mechanical properties sufficient for practical use as monofilaments for fishing nets. Further, as is clear from Table 1, since the dimensional stability is improved, the wear resistance is dramatically improved as compared with Comparative Examples 1 and 2.

Claims (3)

It is a core-sheath type composite monofilament, and the filament is composed of a polyester resin at the core and a polyamide resin at the sheath, and the polyamide resin accounts for 70 to 90% by volume in the filament, and the composite is formed. A monofilament for fishing nets, wherein the cross-sectional area of the cross section of the filament is 7.8 × 10 ^-3 mm ^{2 to} 5.0 × 10 ^-1 mm ^2. The monofilament for fishing nets according to claim 1, wherein the polyamide-based resin accounts for 80 to 90% by volume in the core-sheath type composite monofilament. A monofilament for fishing nets, wherein the fishing net is a bottom tow net or a gill net.

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