JP7022976B2 - Plastic-like mesh and its manufacturing method - Google Patents

Description

The present invention relates to a plastic-like net material used for industrial materials that require high strength and a method for producing the same.

Conventionally, it has been known to use a core-sheath type composite fiber having a core component of polyethylene terephthalate and a sheath component of a polyester copolymer or polyolefin having a lower melting point than polyethylene terephthalate as a material for a mesh sheet. Then, a multifilament yarn made of a core-sheath type composite fiber is used for the warp and weft to weave a coarse woven fabric, and heat treatment is performed to melt the sheath component and fuse the intersections of the warp and weft to form a mesh sheet. It is known (Patent Documents 1 and 2). Here, the reason why the intersections of the warp and weft are fused is to prevent misalignment. At the intersection, fusion occurs even if the heat treatment is not pressed due to the pressure from above and below, and it is difficult for the warp and weft outside the intersection to be fused by the heat treatment, and eventually, the intersection is selectively fused. .. The mesh sheet is mainly attached to the outer structure of a temporary structure such as scaffolding at a construction site, and is used to prevent flying and falling objects from jumping out of the temporary structure. It does not matter if the outer part is not fused.

However, in industrial applications other than mesh sheets, a plastic-like sheet that has higher rigidity by fusing at locations outside the intersection may be required. For example, aquaculture nets are best suited to be plastic-like, as they are subject to constant contact with the fish and are prone to wear, and the fish may bite through the sheet. In order to obtain such a plastic-like sheet, it is considered that heat treatment may be performed while pressing the sheets described in Patent Documents 1 and 2. However, when the sheet is pressed and heat-treated, the sheet becomes rigid and can only be handled as a flat plate, which has a drawback that it is difficult to handle as a scroll.

Therefore, the present inventor has made it an object to provide a plastic-like mesh material that can be wound or folded and handled while being rigid plastic-like, and proposes the following prior inventions. (Patent Document 3). In the prior invention, the net legs and knots are made of a fiber-reinforced plastic material having polyethylene as a base and a plurality of polyethylene terephthalate fibers present in the base, and the mass ratio of the polyethylene to the polyethylene terephthalate fibers is Polyethylene: Polyethylene terephthalate fiber = 1: 1 to 3, which is a plastic-like mesh and a method for producing the same.

Japanese Unexamined Patent Publication No. 2001-271270 Japanese Unexamined Patent Publication No. 2009-299209 Japanese Patent Application No. 2017-137883

However, when the base polyethylene is replaced with polyamide A and the polyethylene terephthalate fiber which is a fiber is replaced with a polyamide B fiber having a melting point higher than that of polyamide A, there is almost no decrease in tensile strength and the knot strength is relatively high. I found. Therefore, an object of the present invention is to provide a plastic-like knotless net material having high knot strength that can be wound or folded and handled while being plastic-like.

That is, in the present invention, the net legs and knots are made of a fiber-reinforced plastic material having polyamide A as a base and a plurality of polyamide B fibers having a higher melting point than the polyamide A in the base. It relates to a plastic-like knotless net material characterized in that the mass ratio of the polyamide A to the polyamide B fiber is polyamide A: polyamide B fiber = 1: 1 to 3 .

Further, in the present invention, a plastic-like knotless net fabric that solves the above-mentioned problems is obtained by forming net legs and nodules by a specific method using a specific core-sheath type composite fiber and then heat-treating. It is a thing. That is, in the present invention, the core component is polyamide B, the sheath component is polyamide A having a lower melting point than the polyamide B, and the mass ratio of the core component to the sheath component is core component: sheath component = 1 to 3: 1. In the process of preparing a multifilament yarn made by bundling a plurality of core-sheath type composite long fibers, a net material composed of net legs and knots is obtained by using a yarn made by aligning a plurality of the multifilament yarns. It is provided with a step of heat-treating the net material to melt only the sheath component in the thread constituting the net leg and the knot and then solidifying it, and the core component is initially contained in the sheath component which became the base. It relates to a method for producing a plastic-like knotless net material composed of net legs and knots that exist in a state where the fiber morphology is maintained.

The plastic-like net material according to the present invention is composed of a net leg 1 and a knot 2. The portion surrounded by the net leg 1 and the nodule 2 is a void and is called a mesh 3. The form of the eye 3 may be a square eye as shown in FIG. 1, or may be another form such as a rhombus. Nodule 2 is nodule-free as shown in FIG . This is because when plastic-like nets are used as fishing nets for aquaculture nets, nodules may damage the fish when they come into contact with the fish. The diameter of the net leg 1 is about 2 to 7 mm, and the area of the nodule 2 is about 25 to 80 mm ² . The area of the eyes 3 is about 5 to 20 cm ² .

The net legs 1 and the nodules 2 are made of a fiber-reinforced plastic material having polyamide A as a base and a plurality of polyamide B fibers 5 present in the base. Polyamide B has a higher melting point than polyamide A. The melting point difference between the polyamide B and the polyamide A is preferably about 50 ° C to 80 ° C. When the melting point difference is less than 50 ° C., when the heat treatment is performed, it becomes difficult to melt or soften only the polyamide A which is the sheath component of the core-sheath type composite fiber, and the fiber formed of the polyamide B maintains its original form. It tends to be difficult to do. Further, when the melting point difference exceeds 80 ° C., the melting point difference between the core component and the sheath component becomes too large, and it tends to be difficult to obtain the core-sheath type composite fiber by the composite melt spinning method. As the polyamide B, a polyamide 6 can generally be adopted. Further, as the polyamide A, a copolymerized polyamide can be generally adopted, and specifically, one obtained by copolymerizing a monomer constituting the polyamide 6, the polyamide 11 or the polyamide 12 at an appropriate ratio is adopted. can do. The mass ratio of the polyamide A to the polyamide B fiber 5 is polyamide A: polyamide B fiber = 1: 1 to 3. If the mass ratio of the polyamide A is lower than this range, it becomes difficult to become a mother body. On the other hand, when the mass ratio of the polyamide B is lower than this range, the diameter or the number of the polyamide B fibers becomes small, and the strength of the fiber reinforced plastic material decreases.

In order to produce the plastic-like net material according to the present invention, first, a core-sheath type composite long fiber having a core component of polyamide B and a sheath component of polyamide A is prepared. In this core-sheath type composite long fiber, the mass ratio of the core component to the sheath component is core component: sheath component = 1 to 3: 1. Polyamide A, which is a sheath component, is a base material for a fiber reinforced plastic material. Therefore, if the mass ratio of the sheath component is lower than this range, it becomes difficult to become a mother. Further, when the mass ratio of the sheath component is higher than this range, the diameter or the number of the core components becomes small, and the strength of the fiber reinforced plastic material decreases. Such core-sheath type composite long fibers can be produced by a conventionally known composite melt spinning method. The fineness of the core-sheath type composite long fiber is about 4 to 20 decitex. A plurality of such core-sheath type composite long fibers are bundled to form a multifilament yarn. The number of focused lines is about 30 to 400.

Next, a plurality of multifilament yarns are pulled together to obtain a yarn. The number of lines is about 5 to 10. Then, by using this thread and hanging it on a braiding machine or a Russell knitting machine, a net material composed of net legs and knots is obtained. Nodules are nodules when hung on a braided machine. When plastic-like nets are used as aquaculture nets, nodules are used for the reasons mentioned above. When hanging on a braiding machine, one thread may be used, but it is preferable to use a plurality of threads of about 2 to 4 by twisting them together. When a plurality of threads are twisted together, the core-sheath type composite long fibers constituting the threads are in close contact with each other, and even if the subsequent heat treatment step is performed under no pressure, the polyamide A, which is a sheath component, is the base material. It becomes easy to become.

The obtained net is heat-treated. The heat treatment temperature is equal to or higher than the melting point of polyamide A, which is a sheath component, and is specifically about 140 to 200 ° C. By this heat treatment, only the sheath component of the core-sheath type composite long fiber constituting the yarn is melted. The heat treatment may be performed under pressure or no pressure, but it is preferably performed under no pressure in order to give flexibility that makes it easier to wind. After the heat treatment, when cooled, the melted sheath component is solidified, and the net leg 1 and the knot 2 become a fiber reinforced plastic material based on polyamide A, which is the sheath component. That is, the net leg 1 and the knot 2 are a fiber reinforced plastic material in which the polyamide B fiber 5 as a core component is present in the polyamide A which is a sheath component as a base in a state where the original fiber morphology is maintained. It is possible to obtain a plastic-like mesh that has become stale. The plastic-like net according to the present invention can be used for conventionally known industrial materials, for example, as a fishing net such as a fixed net, a basket net or aquaculture net, or as a land net such as an exfoliation prevention net or a beast damage net. It can be suitably used.

In the plastic-like net material according to the present invention, the net legs and knots are formed of a high-strength fiber-reinforced plastic material having polyamide A as a base and containing polyamide B fibers. Polyamide is more flexible than polyethylene terephthalate and polyethylene, so that it is plastic-like but easy to wind and fold. Further, since the polyamide A and the polyamide B are compatible with each other, the strength at the nodule is increased. Therefore, the plastic-like net material according to the present invention is difficult to be cut by nodules during use, can be transported as a scroll before and after use, and has an effect of being easy to handle.

Example 1
The core component is polyamide 6 with a melting point of 225 ° C., and the sheath component is a copolymerized polyamide with a melting point of 155 ° C., and the core component: sheath component = 3: 1 (mass ratio). Prepared the fiber. 192 core-sheath type composite long fibers were focused to obtain a multifilament yarn of 1400 decitex / 192 filaments. Eight multifilament yarns were aligned to obtain a yarn. While twisting these three threads (with three twists), they were hung on a braiding machine to obtain a knotless net. This knotless net was introduced into a pin tenter type heat treatment apparatus and heat-treated for 3 minutes in an atmosphere of 175 ° C. while applying tension in the width direction. Then, it was left at room temperature and cooled to obtain a plastic-like mesh. In this plastic-like mesh, the diameter of the mesh leg was about 4 mm, the area of nodule was about 50 mm ² , the mesh was square, and the area was about 10 cm ² .

Reference example 1
A core-sheath composite long fiber with a fineness of about 8.7 decitex, which has a core component of polyethylene terephthalate having a melting point of 260 ° C. and a sheath component of polyethylene having a melting point of 130 ° C., has a core component: sheath component = 3: 1 (mass ratio). Got ready. 192 core-sheath type composite long fibers were focused to obtain a 1670 decitex / 192 filament multifilament yarn. Using this multifilament yarn, a plastic-like mesh was obtained by the same method as in Example 1 except that the atmospheric temperature at the time of heat treatment was changed to 150 ° C.

Reference example 2
A plastic-like mesh was obtained by the same method as in Reference Example 1, except that the sheath component was changed to a copolymerized polyester having a melting point of 160 ° C. and the atmospheric temperature at the time of heat treatment was changed to 180 ° C.

[Measurement of knot strength]
From the plastic-like nets obtained in Example 1 and Reference Examples 1 and 2, test pieces as shown in FIG. 2 were collected so as to have a total of 9 stitches of 3 stitches × 3 stitches in the vertical and horizontal directions. Then, the nodule surrounded by a circle in FIG. 2 was hooked and pulled in the direction of the arrow to measure the strength (nodule strength) when the nodule was broken. As a measuring instrument, an autograph manufactured by Shimadzu Corporation was used, and the measurement was performed under the condition of a tensile speed of 10 cm / min. As a result, the plastic-like mesh of Example 1 was 2572N, that of Reference Example 1 was 2206N, and that of Reference Example 2 was 2096N.

[Measurement of tensile strength]
From the plastic-like nets obtained in Examples 1 and Reference Examples 1 and 2, the central portion of the weft direction net legs was cut in parallel in the warp direction, and test pieces as shown in FIG. 3 were collected. Then, the upper and lower ends in FIG. 3 were grasped by a chuck and pulled in the direction of the arrow to measure the strength (tensile strength) when the net leg in the warp direction was cut. As a measuring instrument, an autograph manufactured by Shimadzu Corporation was used, and the measurement was performed under the conditions of a distance between chucks of 25 cm and a tensile speed of 30 cm / min. As a result, the plastic-like mesh of Example 1 was 1904N, that of Reference Example 1 was 2020N, and that of Reference Example 2 was 1713N.

It is a photograph when the plastic-like net material which concerns on an example of this invention is seen in a plane. It is a schematic diagram which showed the state of the test piece at the time of measuring the nodule strength. It is a schematic diagram which showed the state of the test piece at the time of measuring the tensile strength.

1 net leg 2 nodule 3rd

Claims (4)

The net legs and knots are made of a fiber-reinforced plastic material having polyamide A as a base and a plurality of polyamide B fibers having a melting point higher than that of polyamide A in the base, and the polyamide A and the polyamide B are present. A plastic-like knotless net having a fiber mass ratio of polyamide A: polyamide B fiber = 1: 1 to 3 . The core component is polyamide B, the sheath component is polyamide A having a lower melting point than the polyamide B, and the mass ratio of the core component to the sheath component is core component: sheath component = 1 to 3: 1. The process of preparing a multifilament yarn made by bundling multiple fibers,
A step of obtaining a net consisting of a net leg and a knot using a yarn formed by pulling a plurality of the multifilament yarns, and a process of heat-treating the net, in the yarn constituting the net leg and the knot. It is equipped with a process of melting only the sheath component of the yarn and then solidifying it.
A method for producing a plastic-like knotless net material composed of net legs and nodules in which a core component is present in a sheath component as a base while maintaining the original fiber morphology. The method for producing a plastic-like knotless net material according to claim 2, wherein the net legs and knots are formed by twisting a plurality of threads and heat treatment is performed without pressing. The method for manufacturing a plastic-like knotless net according to claim 2, wherein the net legs and knots are formed by a braiding machine.

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