Net manufacturing method

Abstract

To provide a manufacturing method of a net body by which a same net body can be manufactured by a simple method by further improving conventional manufacturing methods when manufacturing the net body using a polymer net fabric.SOLUTION: A net fabric in a closed state is manufactured by using a crystalline polymer, and the net fabric is fixed in a rectangular opened state by applying tension to a resulting net fabric in the closed state and heat-treating the net fabric in the closed state while maintaining the rectangular opened state. At that time, a polymer of the manufactured net fabric is heat-treated to melt or soften, tension for net fabric opening is applied to the net fabric after the heated polymer is solidified and before the temperature is lowered to a crystallization temperature, and the net fabric is processed into an opened state. Alternatively, the polymer of the manufactured net fabric is heat-treated to melt or soften, the heated polymer is solidified by rapid cooling so as not to cause crystallization, and then the openings are formed in the netting, and then the net fabric is processed into the open net state by applying the tension for the net fabric opening to the net fabric.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a net body. [Background technology]

[0002] Wire mesh is known as a hard net body. Patent Document 1 discloses a hard net body having a rigidity similar to that of wire mesh, which is made by heating a thermoplastic polymer netting while applying tension to the netting to open the mesh, thereby fixing the netting in an open mesh state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-181435 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to further improve the conventional manufacturing method for producing a net body from a mesh fabric made of a thermoplastic polymer, thereby enabling the net body to be produced by a simple technique. [Means for solving the problem]

[0005] In order to achieve this object, the method for manufacturing a net body of the present invention comprises the steps of: A mesh in a stitched state is produced using a crystalline polymer, heat treatment to melt or soften the polymer of the produced mesh; This heated polymer Subsequent cooling After solidification, before the temperature drops to the peak crystallization temperature, tension is applied to the mesh to open the mesh. death, Thereafter, the mesh is cooled to fix the mesh in an open state. It is characterized by:

[0006] Another method for manufacturing a net body of the present invention is to A mesh in a stitched state is produced using a crystalline polymer, heat treatment to melt or soften the polymer of the produced mesh; This heated polymer , so that crystallization does not occur Rapidly cooled and solidified, After that , the solidified polymer is in a state where it is not crystallized or hardened, The mesh is processed into an open mesh state by applying tension to the mesh. death, Thereafter, the mesh is heat-set to fix the mesh in an open mesh state. It is characterized by:

[0007] According to the method for manufacturing a net body of the present invention, it is preferable to use core-sheath composite fibers as the fibers constituting the netting, and to use core-sheath composite fibers in which the core is made of a high-melting point polymer that does not melt at the temperature during heat treatment, and the sheath is made of a low-melting point polymer that melts or softens at the temperature during heat treatment. [Effects of the Invention]

[0008] According to the present invention, the produced mesh polymer is subjected to a heat treatment to melt or soften it, and after the heated polymer has solidified, tension is applied to the mesh to open the mesh before the temperature drops to the peak crystallization temperature, or according to the present invention, the produced mesh polymer is subjected to a heat treatment to melt or soften it, the heated polymer is rapidly cooled to solidify, and tension is then applied to the mesh to open the mesh, thereby allowing the polymer to be applied with tension in a soft, uncrystallized state and processed into an open mesh, which has the advantage of being able to be processed by a simple method. [Brief explanation of the drawings]

[0009] [Figure 1] 1A to 1C are diagrams illustrating examples of a net body obtained by a manufacturing method according to an embodiment of the present invention. [Figure 2] 2 is a diagram illustrating a mesh fabric produced in a bound state for producing the net body of FIG. 1. FIG. [Figure 3]FIG. 3 is a diagram showing the state of the mesh of FIG. 2 when tension is applied to make it open. [Figure 4] 1 is a plan view showing an example of a manufacturing apparatus for carrying out a method for manufacturing a net body according to the present invention. [Figure 5] FIG. 5 is a front view of the manufacturing apparatus of FIG. [Figure 6] FIG. 10 is a diagram showing another example of a manufacturing apparatus for carrying out the manufacturing method of the net body of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1 shows an example of a portion of a net obtained by a manufacturing method according to an embodiment of the present invention. This net has rectangular openings, and the net itself can be manufactured by heat-treating a mesh made of thermoplastic polymer fibers to melt or soften the polymer that forms the fibers, and then cooling and solidifying it.

[0011] FIG. 2 shows an example of the manufacture of a net for producing the net body of FIG. 1. As shown in FIG. 2, the net is manufactured in a stitched state where the mesh is not open. Examples of nets manufactured in this stitched state include knotless netting and netting formed by Russell knitting. This stitched netting has a vertical direction and a horizontal direction. A stitched netting hardly deforms even when tension is applied in the vertical direction, but when tension is applied in the horizontal direction, the stitches open up and become open, as shown in FIG. 3.

[0012] Figure 3 shows the state of the mesh in Figure 2 after tension has been applied manually. The openings are irregular in shape, but by mechanically applying uniform tension in both the vertical and horizontal directions, it is possible to form the openings into a precise rectangular shape as shown in Figure 1.

[0013] By heat treating the mesh in the state shown in Figure 3, the polymer fibers that make up the mesh are melted or softened, and then cooled and solidified, thereby producing the net body shown in Figure 1.

[0014] The mesh shown in Figures 2 and 3 is formed by knitting together yarns made up of a large number of fibers. As a result, there are gaps between the fibers, and these gaps result in a thick knitted fabric. The mesh shown in Figure 2 has selvages formed at its horizontal edges in the direction of the yarn arrangement, and these selvages are formed diagonally along the direction of the yarn arrangement at the edges.

[0015] The net shown in Figure 1 is produced by subjecting the mesh in the open mesh state shown in Figure 3 to a heat treatment while maintaining the open mesh state. When the polymer constituting the fibers is melted or softened and then cooled and solidified during production of the net, the voids between the fibers described above disappear, and as a result, the filaments constituting the net shown in Figure 1 are thinner than the threads constituting the mesh shown in Figures 2 and 3. Figure 1 depicts such thinned filaments.

[0016] (First embodiment) A method for manufacturing a net body according to a first embodiment of the present invention will be described below. In the first embodiment, a closed mesh is manufactured using a crystalline thermoplastic polymer, which is then subjected to a heat treatment, and processed to form an open mesh before the solidified polymer crystallizes, i.e., hardens.

[0017] Any crystalline polymer can be used to form the fibers for the stitched mesh. The polymer fibers can also be in any form. Among these, a preferred fiber form is a sheath-core composite fiber, in which the core is made of a high-melting-point polymer that does not melt at the heat treatment temperature and the sheath is made of a low-melting-point polymer that melts or softens at the heat treatment temperature. When such a sheath-core composite fiber is used, the high-melting-point polymer in the core does not melt during heat treatment, maintaining its fiber shape, thereby reliably maintaining the shape of the net. Meanwhile, the low-melting-point polymer reliably melts or softens during heat treatment and then solidifies upon cooling, allowing the production of a net with the required rigidity. When using sheath-core composite fibers, the low-melting-point polymer in the sheath is melted or softened by heat treatment, and then tension is applied to the mesh to open the mesh before the solidified low-melting-point polymer reaches its crystallization temperature.

[0018] Any polymer can be used to form such core-sheath composite fibers, but it is particularly preferable to use a polyester polymer core and a copolymerized polyester polymer with a lower melting point sheath for the purpose of obtaining a net with the required performance.

[0019] Figures 4 and 5 show an example of a manufacturing apparatus that can be used in the manufacturing method of the first embodiment. Figure 4 is a plan view, and Figure 5 is a front view. That is, Figures 4 and 5 show how a net body 12 is manufactured using a mesh 11. The mesh 11 and net body 12 are processed while traveling in the horizontal direction indicated by arrow A. As described above, the mesh 11 has a vertical direction and a horizontal direction, but the mesh 11 travels in the vertical direction indicated by arrow A.

[0020] That is, a mesh 11 in a stitched state produced by a mesh-making machine (not shown) is passed through a heat treatment device 13 under tension in the longitudinal direction and heat-treated, and heated to a temperature above the melting / softening temperature of the polymer forming the fibers that make up the mesh 11. If the fibers are the above-mentioned core-sheath composite fibers, they are heated to a temperature above the melting point or softening point of the sheath and below the melting point of the core. The mesh 11 in this state is sent out from the heat treatment device 13 as shown in the figure. The mesh 11 at this time is in a stitched state.

[0021] In the illustrated apparatus, a mesh opening device 14 is provided following the heat treatment device 13. This mesh opening device 14 includes a first traveling body 15 that contacts one horizontal end of the netting 11 and a second traveling body 16 that contacts the other horizontal end of the netting 11. Examples of the traveling bodies include rollers and endless belts. These traveling bodies 15 and 16 travel in directions oblique to the vertical and horizontal directions of the netting 11. Frictional forces acting from these traveling bodies 15 and 16 apply vertical tension to the netting 11 while simultaneously applying horizontal tension to the netting 11, thereby opening the netting 11 horizontally. More specifically, as shown in FIG. 5 , each traveling body 15 and 16 is configured such that a pair of traveling elements clamps the end of the netting 11 to apply tension. As a result, the netting that passes through the mesh opening device 14 becomes an open mesh 17.

[0022] In this case, when the mesh 11 is passed through the opening device 14, the mesh 11 supplied from the heat treatment device 13 is in a state in which the polymer that forms the fibers has solidified but has not yet dropped in temperature to the peak crystallization temperature, i.e., is in a state above the peak crystallization temperature of the polymer that forms the fibers.

[0023] Then, although the polymer has solidified, it is still in the stage before hardening due to crystallization, so it can be flexibly deformed and can be easily opened. The opened mesh 17 is cooled after passing through the opening device 14, and can maintain its shape.

[0024] When the process of melting or softening the thermoplastic polymer of the mesh by heat treatment and then applying tension to form an open mesh is carried out continuously, a processing speed of approximately 5 to 25 m / min is preferable. In particular, if the processing speed is less than 5 m / min, there is a risk of gradual crystallization of the polymer that solidifies after melting or softening, making it difficult to process the mesh into an open mesh. Furthermore, the heat treatment and the process of forming the open mesh by applying tension may be performed batchwise rather than continuously. In the case of batch processing, the ambient temperature and the time until the next process should be taken into consideration to prevent gradual crystallization during transport from the heat treatment device for melting or softening to the device for forming the open mesh in the next process. For example, the ambient temperature should be approximately 40°C, and the time required from the end of the heat treatment process to the start of the open mesh process should be approximately 30 seconds.

[0025] (Second embodiment) A method for manufacturing a net according to a second embodiment of the present invention will be described below. In the second embodiment, a mesh in a closed state is manufactured using a crystalline thermoplastic polymer, which is then subjected to a heat treatment, and then rapidly cooled and solidified to prevent crystallization, and processed so that the polymer remains in an uncrystallized, i.e., unhardened state, to form an open mesh.

[0026] Any method can be used to rapidly cool the heat-treated mesh. Furthermore, any method can be used to process the rapidly cooled, closed-loop mesh into an open-loop mesh. FIG. 6 shows an example of a processing device 20 for this purpose. This processing device 20 includes a fixing member 21 and a load-applying member 22. The mesh is rapidly cooled after heat treatment to prevent crystallization of the polymer constituting the fibers, and then cut to the required size. One lateral end of the closed-loop mesh 11 is clamped by the fixing member 21, while the other lateral end of the mesh 11 is clamped by the load-applying member 22. The load-applying member 22 then applies a lateral load to the mesh 11. By applying a load in this manner, an open-loop mesh 17 is formed. By heating the mesh 17 to a temperature above the glass transition point of the polymer constituting the fibers, the mesh 17 can be opened. This produces a net 12. The open-loop mesh can then be fixed by subsequent heat setting. [Example]

[0027] The present invention will now be described with reference to examples. In the examples, the crystallization peak temperature and the glass transition temperature were determined by the following methods.

[0028] (1) Crystallization peak temperature, glass transition temperature: 10 mg of raw yarn (fiber) was weighed out and measured using a Parker-Elmer DSC-7 differential scanning calorimeter. Measurements were performed using a first heating run (heating rate 20°C / min, reaching temperature 200°C) and a first cooling run (heating rate 320°C / min, reaching temperature -50°C). The crystallization peak temperature and glass transition point were then measured during a second heating run (heating rate 20°C / min, reaching temperature 200°C).

[0029] Example 1 Twenty-five strands of core-sheath composite fiber (Unitika "Melset", 1670T192fil-CM27) with a core of polyethylene terephthalate (melting point 256°C) and a sheath of copolymer polyester (melting point 160°C, peak crystallization temperature approximately 90°C) were combined and twisted at S-80T / m while being wound onto a bobbin. The wound yarn was used to knit a knotless mesh in a stitched state.

[0030] 4 and 5, the mesh 11 in the stitched state obtained above was passed through a heat treatment device 13 and subjected to heat treatment at 190°C for 4 minutes. The feed speed ratio of the mesh 11 at the inlet and outlet of the heat treatment device 13 was set so that the speed at the outlet was 1.02 when the speed at the inlet was 1.00.

[0031] The surface temperature of the knotless netting 11 in a stitched state emerging from the heat treatment device 13 was 180°C.

[0032] Without cooling the heat-treated mesh 11, it was continuously subjected to an opening process using the manufacturing apparatus shown in Figures 4 and 5 at a processing speed of 10 m / min while maintaining a surface temperature of 125°C or higher, which is lower than 160°C and higher than the crystallization peak temperature (118°C) of the polymer in the sheath portion of the core-sheath composite fiber, to obtain an open-mesh mesh 17, i.e., a net body 12.

[0033] (Comparative Example 1) Compared to Example 1, the mesh 11 coming out of the heat treatment device 13 was cooled to room temperature in a room temperature atmosphere, and then the mesh was opened by the opening device 14 shown in Figures 4 and 5. Otherwise, the net body 12 was obtained in the same manner as in Example 1.

[0034] (Comparative Example 2) Compared to Example 1, the set temperature of the heat treatment device 13 was set to 220°C, and the surface temperature of the mesh 11 during the opening treatment in the opening device 14 was set to 160°C or higher. Other than that, the net body 12 was obtained in the same manner as in Example 1.

[0035] In Example 1, the polymer constituting the sheath of the core-sheath composite fiber was fluidized in the heat treatment device 13, and then solidified by cooling after leaving the heat treatment device 13. However, crystallization had not progressed and the polymer was flexible and deformable. Therefore, in the opening device 14, the knotless mesh, which was in a closed state, was able to be opened uniformly.

[0036] In contrast, in Comparative Example 1, the polymer constituting the sheath of the core-sheath composite fiber had progressed to crystallization, causing the entire netting 11 to become rigid. This placed a heavy load on the mesh opening device 14, making it impossible to open the meshes uniformly.

[0037] In Comparative Example 2, the polymer constituting the sheath of the core-sheath composite fiber had not yet solidified during the opening treatment. Therefore, although it was possible to open the meshes in the opening device 14, the molten polymer solidified while adhering to the opening device 14, making it impossible to carry out the operation stably.

[0038] Example 2 The processing up to the time when the knotless netting 11 emerged from the heat treatment device 13 was the same as in Example 1. Next, unlike Example 1, cold air with a temperature of 10°C and a dew point of 0°C was blown onto the netting 11 emerging from the heat treatment device 13 to rapidly cool the netting 11. The rapidly cooled netting 11 was cut to the required size and set in the processing device 20 shown in Figure 6. A load was applied by a load application member 22 in an environment of 40°C or higher, which is a temperature above the glass transition point (30°C) of the polymer constituting the sheath portion of the core-sheath composite fiber, to open the mesh. A heat setting process was then performed to obtain a net body.

[0039] (Comparative Example 3) Compared to Example 2, the netting 11 coming out of the heat treatment device 13 was cooled to room temperature in a room temperature atmosphere, and then the mesh was opened by the processing device 20 shown in Fig. 6. A net was obtained in the same manner as Example 2 except for the above.

[0040] In Example 2, the mesh 11, which is a knotless net set in the processing device 20, was subjected to processing for opening after being rapidly cooled to a state in which the crystallization of the polymer constituting the sheath portion of the core-sheath composite fiber had not progressed. Therefore, when processed in an environment at a temperature above the glass transition point of the polymer, the mesh could be easily deformed and opened.

[0041] On the other hand, in Comparative Example 3, the polymer constituting the sheath portion of the core-sheath composite fiber of the mesh 11 had undergone advanced crystallization, so even when subjected to processing in the processing device 20 in an environment with a temperature above the glass transition point, the mesh did not deform and therefore could not be opened.

Claims

1. A mesh in a stitched state is produced using a crystalline polymer, heat treatment to melt or soften the polymer of the produced mesh; After the heated polymer is solidified by subsequent cooling, but before the temperature drops to the crystallization peak temperature, tension for opening the mesh is applied to the mesh to form an open mesh state; The method for manufacturing a net body is characterized in that the mesh is then cooled to fix the mesh in an open mesh state.

2. A mesh in a stitched state is produced using a crystalline polymer, heat treatment to melt or soften the polymer of the produced mesh; The heated polymer is rapidly cooled to solidify it without crystallization, Thereafter, while the solidified polymer is not crystallized and not hardened, tension for opening the mesh is applied to the mesh to form an open mesh state, The method for manufacturing a net body is characterized in that the net is then heat-set to fix the net in an open mesh state.

3. A method for manufacturing a net body as described in claim 1 or 2, characterized in that core-sheath composite fibers are used as the fibers that make up the netting, and this core-sheath composite fiber has a core made of a high-melting point polymer that does not melt at the temperature during heat treatment, and a sheath made of a low-melting point polymer that melts or softens at the temperature during heat treatment.

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