JPS6152259B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for continuously producing a synthetic fiber monofilament network suitable for uses such as aquaculture. Conventionally, wire meshes made of metal wires such as iron wires have been used as nets for fences and cages for aquaculture, but these have been subject to severe corrosion due to rust, which has caused many practical problems. Recently, a mesh body with a quadrilateral mesh constructed by intertwining bent and shaped synthetic fiber monofilaments as shown in Fig. 1 has become known, and this mesh structure can also be applied to the above-mentioned applications. Since there is no rust, you can expect excellent durability. However, the synthetic fiber monofilament network having the configuration shown in Figure 1 is not sufficiently fixed at the connection part a, so when it is applied to a cage for aquaculture and installed in a designated sea area, it may be affected by waves. Alternatively, the material is susceptible to friction caused by back-and-forth movement caused by tidal currents, which causes significant wear and tear on the material.
This often leads to accidents in which the mesh is damaged. In addition, in the above-mentioned net-like body, if the connecting portions are insufficiently fixed, a local mesh phenomenon (a phenomenon in which the mesh reverses around the intersection point of the mesh as a fulcrum and overlaps with the adjacent mesh) occurs in the mesh, Tension concentrates on the deformed mesh, which can easily cause damage to the mesh. In order to prevent such wear, mesh curling, and deformation, it is necessary to frame the mesh and create a fixed structure, but this requires a lot of labor and cost, and the mesh itself The total weight increases and handling becomes difficult. Furthermore, the reticular body having the configuration shown in Figure 1 is manufactured by shaping the synthetic fiber monofilament into a corrugated shape and then intertwining them, making the manufacturing process complicated and making it difficult to make the process continuous. It was hot. Therefore, the present inventors conducted research with the aim of manufacturing a synthetic fiber monofilament network by a continuous process that improves the above-mentioned drawbacks and has excellent durability and strength without wear, mesh return, or deformation. As a result, we have created a mesh body with a specific mesh structure that has reinforced strength and is extremely durable.
The present invention was achieved by establishing a method for manufacturing synthetic fiber monofilaments all at once and continuously. That is, in the present invention, a plurality of synthetic fiber monofilaments are preheated to a temperature above their secondary transition temperature and below their melting point, and are made to intersect with each other, so that straight portions and twisted portions with a twist number of 2 or more are continuous alternately. Each mesh has six fulcrums, at least two sides of which are formed from the twisted parts, and the shape of the mesh is fixed by cooling after weaving while twisting. The present invention provides a method for manufacturing a synthetic fiber monofilament network in which both opposing sides are straight portions or twisted portions. First, the structure of the synthetic fiber monofilament network obtained by the method of the present invention will be explained based on the drawings. Figure 2 shows an example of a net-like body obtained by the method of the present invention, in which a plurality of synthetic fiber monofilaments are crossed with each other, and left at the intersection point, for example, the center point of the twists a and b. Alternatively, it is manufactured by twisting to the right, and constitutes a hexagonal mesh 3 in which straight portions 1 and twisted portions 2 are alternately continuous. In this net-like body, in order to satisfy the strength of the mesh 3, the number of twists in the twisted portion 2 must be 2 or more, preferably 3 to 6.
In addition, the shape of the mesh 3 is a hexagon with six fulcrums, and the twisted portion 2 itself constitutes at least two sides of the mesh 3, so excellent reinforcing effects and durability can be obtained from this point as well. . The fulcrums here are the intersection points at which the monofilament is displaced from the straight portion to the twisted portion or from the twisted portion to the straight portion in each mesh, and in FIG. 2, for example, a and b are the fulcrum points. FIG. 3 shows another embodiment of the synthetic fiber monofilament network obtained by the method of the present invention, in which the network has a rectangular shape. In other words, in the net-like body shown in FIG. 3, the straight portion 1 and the twisted portion 2 are continuous with each other, but the next twisted portion 2 is formed at right angles from the middle of the straight portion 1, so that the mesh is Although the shape of No. 3 is square as a whole, it has six fulcrums, and exhibits excellent reinforcing effect and durability similar to the net-like body having a hexagonal mesh shown in FIG. Next, the method of the present invention for producing the synthetic fiber monofilament network will be explained. First, in the present invention, the synthetic fiber monofilament used as a material for the network body includes polyamides such as nylon 6, nylon 66, nylon 610, and nylon 612, polyesters such as polyethylene terephthalate, polybutylene terephthalate, etc.
Polyvinylidene halides and polyethylene, such as polyvinylidene chloride and polyvinylidene fluoride;
Any monofilament obtained by melt-spinning a thermoplastic synthetic resin such as polyolefin such as polypropylene by a conventional method and having heat fixability can be used.
Note that these monofilaments can contain desired additives such as colorants, pigments, weatherproofing agents, antiwear agents, softeners, algaecides, and flame retardants. Although there is no particular restriction on the diameter of these monofilaments, it is usually preferable to use diameters of 0.5 to 3.0 mm. In the method for manufacturing the net-like body of the present invention, a normal net-making machine can be used, but in order to give the synthetic fiber monofilament bending property, the monofilament is It is necessary to preheat to a temperature above the transition temperature and below the melting point, preferably above the secondary transition temperature and below the softening point.
If the preheating temperature is below the second-order transition temperature of the monofilament, not only will the power load on the net-making machine become large, but the net will warp, and if it exceeds the melting point of the monofilament, the uniformity of the mesh of the net will be reduced. This is undesirable because it lowers strength and strength. As this preheating means, ordinary means such as a hot air bath, a heating medium bath, and a heating plate can be employed. A plurality of monofilaments preheated in this way are then fed to a regular net-making machine, where they are continuously made into the above-mentioned mesh shape, and then cooled to fix the shape. A reticular body can be obtained. Therefore, the method of the present invention includes a monofilament preheating device such as an oven on the upstream side of a screen making machine used in the production of ordinary wire mesh, and a cooling roll and/or a cooling gas blowing device on the downstream side. It is possible to carry out the process as a continuous process using a device equipped with the following. Next, the effects of the synthetic fiber monofilament network obtained by the method of the present invention will be explained. As mentioned above, when a conventional mesh body manufactured by intertwining bent and shaped wire rods is applied to, for example, an aquaculture cage, it is necessary to provide a framework to fix the connecting parts of the mesh. Not only that, but even so, it is still prone to wear, mesh curling, deformation, etc., and these problem areas lead to the mesh breaking.
It was inferior in durability. In contrast, the synthetic fiber monofilament network obtained by the method of the present invention has reinforced mesh connections, so even when it is applied to fish cages for aquaculture, a framework with a simple structure can be used. By doing so, it is possible to fully demonstrate its function, and there is almost no occurrence of mesh or mesh curling or deformation. Therefore, the synthetic fiber monofilament network obtained by the method of the present invention has a long practical service life and excellent durability, and has excellent side effects such as being able to save on framing materials. play. The synthetic fiber monofilament network obtained by the method of the present invention can be used not only for aquaculture but also for livestock sheds, baseball fields, tennis courts, volleyball courses, golf courses, other sports playgrounds, parks, roads, factories, houses, etc. It can be widely used as a net or fence in other areas. The effects of the present invention will be further explained with reference to Examples below. EXAMPLE A mesh body having a mesh shape shown in FIGS. 2 and 3 was manufactured from a polybutylene terephthalate monofilament having a diameter of 2.7 mm. The manufacturing equipment consists of a monofilament feeding device and an air heating oven installed in front of a standard turtle shell netting machine made by Asano Tekko Wire Net Co., Ltd., and a cooling roll and cooling gas blowing device installed immediately after the netting machine. We used a device made by A plurality of polybutylene terephthalate monofilaments pulled out from the monofilament feeding device of the above device are passed through an oven in which air heated to 180 to 200°C is circulated at a flow rate of 0.1 to 0.2 m ² /min. A net-like body A having a regular hexagonal mesh shown in FIG. 2 with the number of twists in the twisted portion being 2 and the length of each side being 3.5 cm was made by using a net-making machine. The net after leaving the net-making machine passes over a metal roll installed immediately after the net-making machine, and blows air at a temperature of 20 to 30°C.
It is cooled and fixed in shape by being sprayed at a rate of 0.3 to 0.5 m ² /min. In addition, in the above, by slowing down the take-up speed of the mesh, the square mesh shown in Fig. 3, in which the number of twists in the twisted part is 2, the side length of the twisted part is 3.5 cm, and the side length of the straight part is 7.0 cm, is formed. A net-like body B having the following was fabricated. On the other hand, for comparison, preheat oven temperature to 60℃.
When netting was made under the same conditions as for manufacturing net-like body A, except for the settings, the power load on the net-making machine was large;
Moreover, the obtained net-like body C was warped and was not usable. In addition, net-like body D was obtained by manufacturing the net-like body A under the same conditions as the manufacturing method of net-like body A, except that the temperature of the preheating oven was set at 300 to 310°C.
Non-uniformity was observed in the shape of the mesh. For further comparison, using the above apparatus, the diameter
A net-like body E having the same mesh shape as the net-like body A was manufactured by making a 2.7 mm iron wire into a net. Furthermore, polyethylene terephthalate monofilament with a diameter of 2.7 mm was preheated, shaped into a wave shape, cooled and fixed, and then intertwined using a standard method. A mesh body F having a diamond-shaped mesh was manufactured. The six types of net-like bodies obtained above were each subjected to a bending fatigue testing machine, and a forced model test equivalent to two years of practical use in seawater was conducted. In addition, the results of various practical tests are also shown in Table 1. The evaluation criteria for each characteristic are as follows. 1 Number of reversal stitches Reversal stitch return refers to a state in which, after practical use, the mesh is reversed starting from the point where the mesh intersects and overlaps with the adjacent mesh. And this number of reversals is
It exists in a total area of ⁵⁰ m2 of the net after 2 years of practical use. It is expressed by the number of overlapping meshes. (The smaller the number of inverted stitches, the better the shape retention of the mesh; conversely, the higher the number, the poorer the shape retention of the mesh, meaning that the network is more likely to be damaged.) 2. Abrasion resistance Each fulcrum of the mesh This refers to a state in which the two parts rub against each other due to tidal currents, causing them to wear out. This wear resistance is expressed by the wear rate shown by the following formula. (The higher the wear rate, the more likely the mesh will be damaged.) Wear rate (%) = [(d ₁ - _{d 2} )/d ₁ ] x 100 d ₁ ... Monofilament diameter at each fulcrum before the 2-year durability test d ₂ ... Monofilament diameter 3 at each fulcrum after the 2-year durability test Durability The observed state of the net-like body after the 2-year durability test is shown. ○...I will not break the net immediately. △...Many broken nets ×...Many broken nets (unusable after 1 year) 4. Squirting property means the resistance value for liquidity. A mesh was placed in seawater in an area with strong tidal currents, and it was observed whether the tidal currents caused bowing motion. ○...Does not cause bowing △...Hardly causes bowing ×...Causes bowing 5 Workability For example, it refers to the ease of assembly when making fish preserves, and the ease of handling and storage of net-like bodies. . ○...Very good ▲...Warpage and difficult to handle △...Requires a framework for assembly and difficult to handle ×...Heavy and difficult to handle 6 Net weight Indicates the weight (kg) per ^1m2 of mesh. The lighter it is, the easier it is to handle. 7 Knitted network property Indicates the knitted network condition of the network. ○...Continuity is possible and good △...Power load is large ▲...Monofilament diameter and mesh shape become uneven ×...Knitting properties are poor, and the fulcrum of the mesh comes off and skips easily occur

[Table] As is clear from the results in Table 1, the nets (A) and (B) obtained by the method of the present invention are free from wear, mesh curling, and deformation, and have excellent durability and strength. Not only that, but the knitting properties are also good and a continuous process can be achieved. On the other hand, the net-like body (C) in which the monofilament is preheated at a low temperature not only warps from the beginning, but also has a high power load during knitting and is inferior in durability.
The reticular body (D) with a high preheating temperature has poor wear rate, durability, and knitting properties. Furthermore, the mesh body (E) having a hexagonal mesh made of metal wires has extremely poor wear rate and durability, and is also poor in workability due to its heavy weight. Furthermore, the net-like body (F) made of synthetic fiber monofilament and having a quadrilateral mesh has problems in terms of reversal, abrasion rate, resistance to squirting, durability, and workability, and it is not possible to create a continuous knitted net. , the knitting properties are also poor.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional net-like body, and FIGS. 2 and 3 are plan views of a net-like body obtained by the method of the present invention. 1 - straight part, 2 - twisted part, 3 - mesh.

Claims (1)

[Claims] 1 Multiple synthetic fiber monofilament part 2
Next, preheat to a temperature above the transition temperature and below the melting point, intersect with each other, and weave by twisting the straight parts and twisted parts with the number of twists of 2 or more in succession alternately, then cool and fix the form. Each mesh has six fulcrums, at least two sides of which are formed from twisted portions, and
A method for producing a synthetic fiber monofilament network in which both opposing sides of the network are straight portions or twisted portions.