Net and net manufacturing method

Abstract

This net is composed of a woven fabric. The net comprises a plurality of warp yarns and a plurality of weft yarns. Each of the plurality of warp yarns and each of the plurality of weft yarns are interwoven at respective intersections to constitute the woven fabric. For each of the plurality of warp yarns and each of the plurality of weft yarns, in a side view of the woven fabric, a length in the thickness direction at each intersection is smaller than a length in the thickness direction elsewhere than the intersections, and in a plan view of the woven fabric, a length in the width direction at each intersection is greater than a length in the width direction elsewhere than the intersections. The opening ratio of the woven fabric is 60% or more.

Description

Net and net manufacturing method

[0001] The present invention relates to a net and a method for manufacturing a net.

[0002] Japanese Patent Laid-Open Publication No. 2021-16846 (Patent Document 1) discloses a support net for a pleated filter composite. In this support net for a pleated filter composite, a woven fabric is formed from a plurality of warp yarns and a plurality of weft yarns (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2021-16846

[0004] In various nets, including support nets for pleated filters, there are cases where a relatively high opening ratio and a relatively thin thickness are required at the same time. However, Patent Document 1 does not disclose a means for solving this problem.

[0005] The present invention has been made to solve such problems, and its object is to provide a net that can achieve both a relatively high opening rate and a relatively thin thickness, and a method for manufacturing such a net.

[0006] A net according to one aspect of the present invention is made of woven fabric. The net includes a plurality of warp threads and a plurality of weft threads. The woven fabric is made up of each of the plurality of warp threads and each of the plurality of weft threads crossing each other at each intersection. For each of the plurality of warp threads and each of the plurality of weft threads, in a side view of the woven fabric, the thickness length at each intersection is shorter than the thickness length at any other point, and in a plan view of the woven fabric, the width length at each intersection is longer than the width length at any other point. The opening ratio of the woven fabric is 60% or more.

[0007] In this net, for each of the multiple warp threads and each of the multiple weft threads, the thickness direction length at each intersection is shorter than the thickness direction length at other locations in the woven fabric when viewed from the side. Therefore, with this net, the thickness of the net can be reduced compared to when, for each of the multiple warp threads and each of the multiple weft threads, the thickness direction length at each intersection is the same as the thickness direction length at other locations in the woven fabric when viewed from the side. Furthermore, with this net, the opening ratio of the woven fabric is 60% or more. Therefore, with this net, it is possible to achieve both a relatively high opening ratio and a relatively thin thickness.

[0008] In the net, each of the plurality of warp threads and each of the plurality of weft threads do not have to be welded to each other at each intersection.

[0009] The inventor(s) discovered that the strength of a net decreases when multiple warp threads and multiple weft threads are welded to each other at each intersection. In this net, multiple warp threads and multiple weft threads are not welded to each other at each intersection. Therefore, this net can maintain a relatively high strength.

[0010] In the above net, for each of the plurality of warp threads and each of the plurality of weft threads, the widthwise length at each intersection may be 1.5 times or more the widthwise length at any other point than the intersection in a plan view.

[0011] In the above net, for each of the plurality of warp threads and each of the plurality of weft threads, the widthwise length at each intersection in a planar view may be 1.0 times or more and 2.0 times or less the thickness of the woven fabric.

[0012] In the above net, the thickness of the net at each intersection may be 1.5 times or less the thickness of the net other than the intersections in a side view.

[0013] In the net, each of the plurality of warp threads and each of the plurality of weft threads may be made of thermoplastic fluorine-based resin fibers.

[0014] A method for manufacturing a net according to another aspect of the present invention includes the steps of preparing a plurality of warp threads and a plurality of weft threads, constructing a woven fabric by crossing each of the plurality of warp threads and each of the plurality of weft threads at each intersection, and rolling the woven fabric so that, in a side view of the woven fabric, the thickness length at each intersection is shorter than the thickness length at any other intersection, and, in a plan view of the woven fabric, the width length at each intersection is longer than the width length at any other intersection. The loss of opening rate of the woven fabric due to the rolling is 10% or less.

[0015] In this net manufacturing method, the woven fabric is rolled so that, for each of the multiple warp yarns and each of the multiple weft yarns, the thickness direction length at each intersection is shorter than the thickness direction length at any other point in a side view of the woven fabric. Therefore, this net manufacturing method can manufacture a net with reduced thickness. Furthermore, in this net manufacturing method, the loss in the opening rate of the woven fabric due to rolling is 10% or less. Therefore, this net manufacturing method can manufacture a net that achieves both a relatively high opening rate and a relatively thin thickness.

[0016] According to the present invention, it is possible to provide a net that can achieve both a relatively high opening ratio and a relatively thin thickness, and a method for manufacturing the net.

[0017] 3 is a plan view schematically showing a portion of a net. FIG. 4 is a view schematically showing a cross section taken along II-II in FIG. 1. FIG. 5 is a plan view schematically showing a portion of a first comparative net. FIG. 6 is a view schematically showing a cross section taken along IV-IV in FIG. 3. FIG. 7 is a plan view schematically showing a portion of a second comparative net. FIG. 8 is a perspective view schematically showing a portion of a net manufacturing apparatus. FIG. 9 is a view showing a partially enlarged photograph of the net of Example 1. FIG. 10 is a view showing a partially enlarged photograph of the net of Example 2. FIG. 11 is a view showing a partially enlarged photograph of the net of Example 3. FIG. 12 is a view showing a partially enlarged photograph of the net of Comparative Example 1. FIG. 13 is a view showing a partially enlarged photograph of the net of Comparative Example 2. FIG. 14 is a view showing a partially enlarged photograph of the net of Comparative Example 3. FIG. 15 is a view showing a partially enlarged photograph of the net of Comparative Example 4. FIG. 16 is a view showing a partially enlarged photograph of the net of Comparative Example 5. FIG. 17 is a view showing a partially enlarged photograph of the net of Comparative Example 6.

[0018] An embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described in detail below with reference to the drawings. Note that identical or corresponding parts in the drawings are designated by the same reference numerals, and their description will not be repeated. Furthermore, for ease of understanding, each drawing is drawn in a schematic manner with objects appropriately omitted or exaggerated.

[0019] [1. Configuration of the Net] Fig. 1 is a plan view schematically showing a part of a net 10 according to the present embodiment. Referring to Fig. 1, the net 10 is used, for example, as a support net to be combined with various filters such as pleated filters. However, the use of the net 10 is not limited to this.

[0020] The net 10 includes a plurality of warp threads 100 and a plurality of weft threads 200. Each warp thread 100 and each weft thread 200 is made of, for example, a thermoplastic fluororesin fiber. That is, each warp thread 100 and each weft thread 200 is made of, for example, PTFE (polytetrafluoroethylene) or PFA (perfluoroalkoxyalkane). The diameter of the warp thread 100 and the diameter of the weft thread 200 are approximately the same.

[0021] In the net 10, a woven fabric is formed by each of the multiple warp threads 100 and each of the multiple weft threads 200 crossing each other at each intersection IR1. In this example, each of the multiple warp threads 100 and each of the multiple weft threads 200 are perpendicular to each other at each intersection IR1. The manufacturing procedure for the net 10 will be described later. During the manufacturing process of the net 10, the warp threads 100 and the weft threads 200 are rolled in a heated state, resulting in deformation of each of the warp threads 100 and the weft threads 200 at each intersection IR1. Note that each of the multiple warp threads 100 and each of the multiple weft threads 200 are not welded to each other at each intersection IR1.

[0022] Specifically, at the intersection IR1, each warp yarn 100 and each weft yarn 200 is compressed in the thickness direction of the net 10 and stretched in both the MD (Machine Direction) and TD (Transverse Direction) of the net 10. For example, in a plan view, the widthwise length TD1 of the warp yarn 100 at the intersection IR1 is longer than the widthwise length WD1 of the warp yarn 100 at any point other than the intersection IR1, and the widthwise length MD1 of the weft yarn 200 at the intersection IR1 is longer than the widthwise length WD2 of the weft yarn 200 at any point other than the intersection IR1. For example, with respect to each of the multiple warp yarns 100 and each of the multiple weft yarns 200, in a plan view, the widthwise length at each intersection IR1 is 1.3 times or more, preferably 1.5 times or more, and more preferably 1.7 times or more, of the widthwise length at any point other than the intersection IR1.

[0023] FIG. 2 is a schematic diagram of the II-II cross section of FIG. 1 (a side view of the net 10). As shown in FIG. 2, the warp yarn 100 and the weft yarn 200 are crushed against each other at the intersection IR1. Therefore, for example, the thickness-wise length TH2 of the weft yarn 200 at the intersection IR1 is shorter than the thickness-wise length TH1 of the weft yarn 200 at other locations. The height position (thickness-wise position) of the intersection IR1 is higher by a length HT1 than the height positions at other locations. In other words, the intersection IR1 is elevated by a length HT1 relative to the portions other than the intersection IR1. For example, for each of the multiple warp yarns 100 and each of the multiple weft yarns 200, in a planar view, the width-wise length at each intersection IR1 is 0.6 to less than 2.1 times the thickness TN1 of the net 10 (woven fabric), and preferably 1.0 to 2.0 times. Furthermore, when viewed from the side of the net 10, the thickness TN1 of the net 10 at the intersection IR1 is, for example, 1.5 times or less the length TH1 in the thickness direction (thickness direction of the net 10) of the warp threads 100 and weft threads 200 other than the intersection IR1, and preferably 1.2 times or less.

[0024] Referring again to Figure 1, a plurality of openings AR1 are formed in the net 10. The opening ratio of the net 10 is 60% or more, preferably 65% ​​or more, and more preferably 70% or more. The opening ratio is calculated by dividing the area of ​​the opening AR1 by the area of ​​the smallest region TR1 surrounded by two adjacent warp yarns 100 and two adjacent weft yarns 200. Each side of the region TR1 overlaps with the central axis of the warp yarns 100 or the weft yarns 200 in a plan view.

[0025] In the net 10 according to the present embodiment, for each of the plurality of warp yarns 100 and each of the plurality of weft yarns 200, in a side view of the net 10 (woven fabric), the thickness direction length TH2 at each intersection IR1 is shorter than the thickness direction length TH1 at any point other than the intersection IR1. The reason why the net 10 has such a feature will be explained below.

[0026] Fig. 3 is a plan view schematically showing a portion of a first comparative net 10X. As shown in Fig. 3, the net 10X includes a plurality of warp yarns 100X and a plurality of weft yarns 200X. In the net 10X, each of the plurality of warp yarns 100X and each of the plurality of weft yarns 200X intersect with each other at each intersection IR1X to form a woven fabric.

[0027] In the net 10X, the warp yarns 100X and the weft yarns 200X are not deformed at each intersection IR1X. Therefore, in a plan view, the widthwise length TD1X of the warp yarns 100X at the intersection IR1X is the same as the widthwise length WD1X of the warp yarns 100X at other than the intersection IR1X, and the widthwise length MD1X of the weft yarns 200X at the intersection IR1X is the same as the widthwise length WD2X of the weft yarns 200X at other than the intersection IR1X.

[0028] FIG. 4 is a schematic diagram showing the cross section IV-IV of FIG. 3 . As shown in FIG. 4 , the warp yarns 100X and the weft yarns 200X are bent but not crushed against each other. Therefore, for example, the thickness direction length TH2X of the weft yarn 200X at the intersection IR1X is the same as the thickness direction length TH1X of the weft yarn 200X at points other than the intersection IR1X. As a result, the thickness TN1X of the net 10X is thicker than the thickness TN1 of the net 10 according to the present embodiment (see FIG. 2 ). That is, with the net 10 according to the present embodiment, for each of the multiple warp yarns 100 and each of the multiple weft yarns 200, in a side view of the net 10 (woven fabric), the thickness direction length TH2 at each intersection IR1 is shorter than the thickness direction length TH1 at points other than the intersection IR1. Therefore, the thickness of the net 10 can be reduced, for example, compared to the example (first comparative example) shown in FIG. 3 .

[0029] Fig. 5 is a plan view schematically showing a portion of a second comparative net 10Y. As shown in Fig. 5, the net 10Y includes a plurality of warp threads 100Y and a plurality of weft threads 200Y. In the net 10Y, each of the plurality of warp threads 100Y and each of the plurality of weft threads 200Y intersects with each other at each intersection IR1Y to form a woven fabric.

[0030] In the net 10Y, the warp yarns 100Y and the weft yarns 200Y are deformed not only at the intersection IR1Y but also at other locations. Therefore, the area of ​​the opening AR1Y is smaller than that of the opening AR1 of the net 10 according to the present embodiment. As a result, the opening ratio of the net 10Y is smaller than that of the net 10 according to the present embodiment. In manufacturing the net 10 according to the present embodiment, adjustments are made so that the intersection IR1 is primarily deformed and that portions other than the intersection IR1 are hardly deformed at all. As a result, the net 10 according to the present embodiment can achieve both a relatively high opening ratio and a relatively thin thickness.

[0031] [2. Net Manufacturing Method] The net 10 according to this embodiment is manufactured by rolling, in a heated state, a woven fabric composed of a plurality of warp threads 100 and a plurality of weft threads 200. The woven fabric before rolling is manufactured using various known looms. The woven fabric before rolling is manufactured, for example, through a step of preparing a plurality of warp threads 100 and a plurality of weft threads 200, and a step of crossing each of the plurality of warp threads 100 and each of the plurality of weft threads 200 at each intersection point IR1.

[0032] Fig. 6 is a perspective view schematically showing a portion of a net manufacturing apparatus 30. Referring to Fig. 6, the net manufacturing apparatus 30 is configured to roll a woven fabric composed of a plurality of warp threads 100 and a plurality of weft threads 200 in a heated state. The net manufacturing apparatus 30 includes rolls 300 and 310. The woven fabric is sandwiched between the rolls 300 and 310 and transported downstream. Each of the rolls 300 and 310 is made of metal, for example, and configured to heat the woven fabric to a temperature equal to or higher than the glass transition point and lower than the melting point of the raw materials of the warp threads 100 and the weft threads 200. The net 10 is manufactured by sandwiching the woven fabric between the heated rolls 300 and 310 and transporting it downstream. That is, by sandwiching the fabric between the rolls 300, 310, the thickness direction length at each intersection IR1 of each of the plurality of warp yarns 100 and each of the plurality of weft yarns 200 becomes shorter in a side view of the fabric than the thickness direction length at other than the intersection IR1, and the width direction length at each intersection IR1 becomes longer in a plan view of the fabric than the width direction length at other than the intersection IR1. Furthermore, the loss (reduction rate) of the opening ratio of the fabric due to rolling is 10% or less, and preferably 5% or less.

[0033] [3. Features] As described above, in the net 10 according to the present embodiment, for each of the multiple warp yarns 100 and each of the multiple weft yarns 200, the thickness direction length at each intersection IR1 is shorter than the thickness direction length at any other point than the intersection IR1 in a side view of the net 10 (woven fabric). Therefore, with the net 10, the thickness of the net 10 can be reduced compared to when, for each of the multiple warp yarns 100 and each of the multiple weft yarns 200, the thickness direction length at each intersection IR1 is the same as the thickness direction length at any other point than the intersection IR1 in a side view of the net 10. Furthermore, the opening rate of the woven fabric in the net 10 is 60% or more. Therefore, with the net 10, it is possible to achieve both a relatively high opening rate and a relatively thin thickness.

[0034] Furthermore, the inventor(s) found that when each of the plurality of warp threads 100 and each of the plurality of weft threads 200 are welded to each other at each intersection IR1, the strength of the net 10 decreases. In the net 10, each of the plurality of warp threads 100 and each of the plurality of weft threads 200 are not welded to each other at each intersection IR1. Therefore, the net 10 can maintain a relatively high strength.

[0035] [4. Other Embodiments] The concept of the above embodiment is not limited to the embodiment described above. Below, examples of other embodiments to which the concept of the above embodiment can be applied will be described.

[0036] In the net 10 according to the above embodiment, each of the plurality of warp threads 100 and each of the plurality of weft threads 200 are perpendicular to each other. However, each of the plurality of warp threads 100 and each of the plurality of weft threads 200 do not necessarily have to be perpendicular to each other. It is sufficient that each of the plurality of warp threads 100 and each of the plurality of weft threads 200 cross each other.

[0037] In the net 10 according to the above embodiment, the warp threads 100 and the weft threads 200 are each made of thermoplastic fluororesin fibers. However, the warp threads 100 and the weft threads 200 do not necessarily have to be made of thermoplastic fluororesin fibers. The warp threads 100 and the weft threads 200 may be made of, for example, other thermoplastic resin fibers.

[0038] The above describes exemplary embodiments of the present invention. That is, the detailed description and the accompanying drawings are disclosed for the purpose of illustrative explanation. Therefore, some of the components described in the detailed description and the accompanying drawings may be non-essential components for solving the problems. Therefore, just because these non-essential components are described in the detailed description and the accompanying drawings, it should not be immediately recognized that these non-essential components are essential.

[0039] Furthermore, the above-described embodiments are merely illustrative of the present invention in all respects. Various improvements and modifications to the above-described embodiments are possible within the scope of the present invention. For example, at least a portion of the configuration of any of the embodiments may be combined with at least a portion of the configuration of any of the other embodiments. In other words, when implementing the present invention, specific configurations can be appropriately adopted depending on the embodiment.

[0040] Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

[0041] [1. Examples and Comparative Examples] Nets of Examples 1-3 and Comparative Examples 1-6 were produced. The warp and weft yarns constituting each net were each made of PFA fiber. The diameter of each of the warp and weft yarns used to produce each net was 38 μm.

[0042] The net of Comparative Example 1 was composed of a woven fabric that was not rolled in a heated state. Examples 1-3 and Comparative Examples 2-6 were manufactured using a net manufacturing apparatus as shown in Figure 6. When manufacturing the nets of Examples 1-3 and Comparative Example 3, the woven fabric was sandwiched between two metal rolls to produce the net. The temperature of each roll was 300°C or less. When manufacturing the net of Comparative Example 2, the woven fabric was sandwiched between a metal roll and a rubber roll to produce the net. The temperature of each roll was 200°C or less. When manufacturing the nets of Comparative Examples 4-6, the woven fabric was sandwiched between two metal rolls to produce the net. The temperature of each roll was 315°C or more.

[0043] 7, 8, 9, 10, 11, 12, 13, 14, and 15 are partial enlarged photographs of the nets of Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, and Comparative Example 6, respectively. In the nets of Examples 1-3 and Comparative Examples 1-3, the warp and weft yarns were not fused to each other at the intersections. On the other hand, in the nets of Comparative Examples 4-6, the warp and weft yarns were fused to each other at the intersections.

[0044] [2. Measurement of Various Parameters] Each net was observed under magnification (magnification: 400x) using a laser microscope manufactured by Keyence Corporation (model number: VK-X1000), and the opening ratio, intersection size, yarn width at parts other than the intersections, yarn thickness at parts other than the intersections, and height difference between the intersections and parts other than the intersections were measured for each net.

[0045] The film thickness of each net was measured using a micrometer manufactured by Mitutoyo Corporation (model number: MDC-25PXT).

[0046] The maximum strength of each net was measured using a tensile tester (model number: EX-LX) manufactured by Shimadzu Corporation (test piece width: 20 mm, test length: 40 mm, test speed: 40 mm / min).

[0047] [3. Measurement Results] The measurement results are shown in Table 1 below.

[0048] In Table 1, the portions marked with "-" are portions that could not be measured. As shown in Table 1, the film thickness was thick in Comparative Example 1, and the aperture ratios were low in Comparative Examples 2 to 6. Furthermore, the maximum point strength was low in Comparative Example 4. On the other hand, in Examples 1 to 3, the film thickness was sufficiently thin, the aperture ratio was sufficiently high, and the maximum point strength was sufficiently high.

[0049] 10 Net, 30 Net manufacturing device, 100 Warp thread, 200 Weft thread, 300, 310 Roll, AR1 Opening, IR1 Intersection, HT1, MD1, TD1, TH1, TH2, WD1, WD2 Length, TN1 Thickness, TR1 Area.

Claims

1. A net made of woven fabric, comprising a plurality of warp threads and a plurality of weft threads, wherein the woven fabric is made up of each of the plurality of warp threads and each of the plurality of weft threads crossing each other at each intersection, wherein for each of the plurality of warp threads and each of the plurality of weft threads, in a side view of the woven fabric, the thickness length at each intersection is shorter than the thickness length at any other point, and in a plan view of the woven fabric, the width length at each intersection is longer than the width length at any other point, and the opening ratio of the woven fabric is 60% or more.

2. The net according to claim 1, wherein each of said plurality of warp threads and each of said plurality of weft threads are not fused to each other at each of said intersections.

3. A net as described in claim 1 or claim 2, wherein for each of the plurality of warp threads and each of the plurality of weft threads, the widthwise length at each intersection in the planar view is 1.5 times or more the widthwise length at any other point than the intersection.

4. A net as described in claim 1 or claim 2, wherein for each of the plurality of warp threads and each of the plurality of weft threads, the widthwise length at each intersection in the planar view is 1.0 times or more and 2.0 times or less the thickness of the woven fabric.

5. A net as described in claim 1 or claim 2, wherein, in the side view, the thickness of the net at each intersection is 1.5 times or less the thickness of the net other than each intersection.

6. A net according to claim 1 or claim 2, wherein each of the plurality of warp threads and each of the plurality of weft threads are made of thermoplastic fluorine-based resin fibers.

7. A method for manufacturing a net, comprising: a step of preparing a plurality of warp threads and a plurality of weft threads; a step of constructing a woven fabric by crossing each of the plurality of warp threads and each of the plurality of weft threads with each other at each intersection; and a step of manufacturing the net by rolling the woven fabric so that, for each of the plurality of warp threads and each of the plurality of weft threads, in a side view of the woven fabric, the thickness length at each intersection is shorter than the thickness length at any other point, and in a plan view of the woven fabric, the width length at each intersection is longer than the width length at any other point, wherein the loss in the opening rate of the woven fabric due to the rolling is 10% or less.

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