WO2024161867A1 - Industrial woven fabric - Google Patents

Abstract

An industrial woven fabric 10 comprises a first warp, a second warp, a first weft, and a second weft. The first warp and the second warp are provided in a misaligned manner in a weft direction. The first weft and the second weft are provided in a misaligned manner in a warp direction. The second weft is positioned on an upper surface side of the industrial woven fabric. The first warp is interlaced only with the first weft. The second warp is interlaced with the first weft and the second weft.

Description

Industrial Fabrics

The present invention relates to industrial fabrics used to manufacture nonwoven fabrics.

Conventionally, industrial fabrics woven from warp and weft threads have been widely used as industrial fabrics for use in nonwoven fabric manufacturing equipment. There are various characteristics required for industrial fabrics, but for example, Patent Document 1 discloses a multi-layered nonwoven fabric having a first warp thread, a second warp thread, an upper surface side weft thread, and a lower surface side weft thread. In this multi-layered nonwoven fabric, the first warp thread is woven into all layers of weft threads from the upper surface side weft thread to the lower surface side weft thread, and the second warp thread is woven into only the upper surface side weft thread.

International Publication No. 2012-140992

Incidentally, the industrial fabric is attached to the nonwoven fabric manufacturing device as an endless belt. A plurality of loops are formed by the warp threads at both ends of the industrial fabric, and the weft threads are inserted into the loops to connect both ends of the industrial fabric, making the industrial fabric endless. In the multi-layer nonwoven fabric described in Patent Document 1, the second warp threads weave only the upper surface side weft threads with a small wire diameter, so the loops formed by folding back the second warp threads may protrude to the upper surface side in accordance with the position of the upper surface side weft threads, forming a step in the belt body. If a step is formed in the belt body, the uniformity of the nonwoven fabric manufactured using the belt will be impaired only at the step portion, causing poor formation of the nonwoven fabric.

The object of the present invention is to provide an industrial fabric with loops that become smooth and have a stable shape when made into an endless belt.

In order to solve the above problem, one aspect of the present invention is an industrial fabric composed of a first warp thread, a second warp thread, a first weft thread, and a second weft thread, in which the first warp thread and the second warp thread are offset in the weft direction, the first weft thread and the second weft thread are offset in the warp direction, the second weft thread is located on the upper surface side of the industrial fabric, the first warp thread is woven only into the first weft thread, and the second warp thread is woven into the first weft thread and the second weft thread.

The present invention provides an industrial fabric with loops that become smooth and have a stable shape when made into an endless belt.

FIG. 1 is a design diagram showing a complete design of an industrial woven fabric according to an embodiment of the present invention. FIG. 2 is a cross-sectional view in the warp direction along the warp yarns of the industrial fabric shown in FIG. FIG. 2 is a cross-sectional view taken along a first warp thread of the industrial fabric shown in FIG. 1 . FIG. 2 is a diagram for explaining loops formed by a second warp yarn in an industrial fabric. 11A and 11B are diagrams for explaining a small loop formed by a first warp yarn.

In the following explanation, "warp threads" are threads that extend in the direction in which the paper raw material is transported when the multilayer papermaking fabric is made into an endless belt, and "weft threads" are threads that extend in a direction that crosses the warp threads. Additionally, the "upper side" is the side of the nonwoven fabric manufacturing belt where the raw material is transported, and the "lower side" is the side of the nonwoven fabric manufacturing belt that mainly comes into contact with the drive roller. The "surface" is the surface that is exposed on the upper or lower side.

　A "design pattern" is the smallest repeating unit of a woven fabric and corresponds to the complete structure of the fabric. In other words, a "woven fabric" is formed by repeating a "complete structure" back and forth and left and right. A "knuckle" refers to the part where a warp thread passes over or under one or more weft threads and is exposed on the surface.

Figure 1 is a design diagram showing the complete structure of an industrial fabric 10 according to an embodiment. Figure 2 is a cross-sectional view in the warp direction along the warp threads of the industrial fabric 10 shown in Figure 1. Figure 2(a) shows a cross-section of a first warp pair formed by first warp threads 1f and 2f, and Figure 2(b) shows a cross-section of a second warp pair formed by second warp threads 3s and 4s.

In the design drawings, warp threads are indicated by Arabic numerals, e.g., 1, 2, 3.... Weft threads are indicated by Arabic numerals with a prime, e.g., 1', 2', 3'.... First warp threads and first weft threads are indicated by numerals with an f, and second warp threads and second weft threads are indicated by numerals with an s.

In addition, in the design drawings, an X mark indicates that the first warp thread and the second warp thread are arranged above the first weft thread and the second weft thread, and an unmarked square indicates that the first warp thread and the second warp thread are arranged below the first weft thread and the second weft thread.

The industrial fabric 10 shown in FIG. 1 includes first warp threads (1f, 2f, 5f, 6f), second warp threads (3s, 4s, 7s, 8s), first weft threads (1'f, 3'f, 5'f, 7'f), and second weft threads (2's, 4's, 6's, 8's). In the complete weave of the repeating pattern of the industrial fabric 10, the first warp threads (1f, 2f, 5f, 6f) and second warp threads (3s, 4s, 7s, 8s) are eight in number, and the first weft threads (1'f, 3'f, 5'f, 7'f) and second weft threads (2's, 4's, 6's, 8's) are eight in number.

The first weft threads (1'f, 3'f, 5'f, 7'f) have a larger diameter than the second weft threads (2's, 4's, 6's, 8's), and may be set to be, for example, 1.5 to 3 times the diameter of the second weft threads (2's, 4's, 6's, 8's). In the complete weave, the first warp threads (1f, 2f, 5f, 6f) are four, the second warp threads (3s, 4s, 7s, 8s) are four, the first weft threads (1'f, 3'f, 5'f, 7'f) are four, and the second weft threads (2's, 4's, 6's, 8's) are four. Here, the relationship between the first weft threads and the second weft threads will be explained with reference to Figure 3.

FIG. 3 is a cross-sectional view taken along the first warp thread 1f of the industrial fabric 10 shown in FIG. 1. The first weft threads (1'f, 3'f, 5'f, 7'f) and the second weft threads (2's, 4's, 6's, 8's) are arranged alternately. This allows the second weft threads to be arranged between the first weft threads, which have a larger wire diameter, and function as floating threads.

The first weft threads (1'f, 3'f, 5'f, 7'f) and the second weft threads (2's, 4's, 6's, 8's) are offset in the warp direction. The first weft thread 1'f and the second weft thread 2's are spaced apart in the warp direction by a gap C, and the other first and second weft threads also have a similar gap C. The gap C between the first and second weft threads provides a space for weaving the first and second warp threads around the first weft thread, which serves as the axis.

The second weft threads (2's, 4's, 6's, 8's) are located on the upper surface side of the industrial fabric 10. A line L2 passing through the centers of the multiple second weft threads (2's, 4's, 6's, 8's) is located on the upper surface side of a line L1 passing through the centers of the multiple first weft threads (1'f, 3'f, 5'f, 7'f). This allows the second weft threads (2's, 4's, 6's, 8's) to function as floating threads.

Returning to Figures 1 and 2, the first warp threads (1f, 2f, 5f, 6f) are woven only with the first weft threads (1'f, 3'f, 5'f, 7'f). The first warp threads are not woven with the second weft threads, preventing them from pulling the second weft threads to the underside. The second warp threads (3s, 4s, 7s, 8s) are woven with the first weft threads (1'f, 3'f, 5'f, 7'f) and the second weft threads (2's, 4's, 6's, 8's). The second warp threads also weave with the second weft threads, connecting the second weft threads to the first weft threads.

The first warp threads (1f, 2f, 5f, 6f) pass under all the second weft threads (2's, 4's, 6's, 8's) and have an interwoven pattern that alternates between going up and down the first weft threads (1'f, 3'f, 5'f, 7'f). This allows the first warp threads to be finely woven into only the first weft threads.

A pair of first warp threads (1f, 2f) are adjacent in the weft direction to form a first warp pair. The other pair of first warp threads (5f, 6f) are similarly adjacent in the weft direction to form a first warp pair. The adjacent first warp threads (1f and 2f, 5f and 6f) that form the first warp pair are woven with a shift of one thread each in the warp direction relative to the first weft thread (1'f, 3'f, 5'f, 7'f). The first warp threads (1f, 2f, 5f, 6f) form a weaving pattern in which they are woven alternately above and below the first weft thread (1'f, 3'f, 5'f, 7'f). As a result, as shown in Figure 2(a), the pair of first warp threads can be woven so as to sandwich the first weft thread from above and below, and the pair of first warp threads arranges the second weft thread to float on the upper surface side. By arranging the second weft threads as floating threads between the first weft threads, which have a larger wire diameter, the mesh of the industrial fabric 10 becomes finer, and the penetration of the nonwoven fibers is suppressed.

In the complete weave forming the repeating pattern of the industrial fabric 10, the weaving patterns of one first warp pair (1f, 2f) and the other first warp pair (5f, 6f) are identical. Specifically, the weaving patterns of the first warp thread 1f and the first warp thread 5f are identical, and the weaving patterns of the first warp thread 2f and the first warp thread 6f are identical. The same weaving pattern means that the first warp threads weave into the same first weft thread.

A pair of second warp threads (3s, 4s) are adjacent in the weft direction to form a second warp thread pair. The other pair of second warp threads (7s, 8s) are similarly adjacent in the weft direction to form a second warp thread pair. The pairs of second warp threads (3s and 4s, and 7s and 8s) that form the second warp thread pair are woven with a warp offset of two threads from each other in the warp direction relative to the second weft threads (2's, 4's, 6's, 8's). In other words, the second warp thread 3s is woven so as to pass above the second weft thread 2's, and the second warp thread 4s is woven so as to pass above the second weft thread 6's, and the weaving pattern of the second warp threads 3s and 4s has an offset of two threads relative to the second weft thread.

The second warp thread 3s passes over one first weft thread 1'f, one second weft thread 2's, and one first weft thread 3'f in order, and then passes under one second weft thread 4's, one first weft thread 5'f, one second weft thread 6's, one first weft thread 7'f, and one second weft thread 8's in order, forming a weaving pattern. Each of the other second warp threads (4s, 7s, 8s) passes over one first weft thread, one second weft thread, and one first weft in order, and then passes under one second weft thread, one first weft thread, one second weft thread, one first weft thread, and one second weft in order, forming a weaving pattern. In other words, each of the second warp threads (3s, 4s, 7s, 8s) forms a common weaving pattern.

In the complete weave forming the repeating pattern of the industrial fabric 10, the weaving patterns of the two second warp pairs (3s and 4s, and 7s and 8s) are common. One second warp pair (3s and 4s) and the other second warp pair (7s and 8s) form a weaving pattern shifted by one warp thread in the warp direction with respect to the first weft or the second weft. The second warp thread 3s and the second warp thread 7s are shifted by one warp thread with respect to the first weft, and the second warp thread 4s and the second warp thread 8s are shifted by one warp thread with respect to the first weft. In this way, although the weaving patterns of the two second warp pairs (3s and 4s, and 7s and 8s) are common, they are shifted in the warp direction. This makes it possible to weave the first weft and the second weft evenly.

The first warp threads (1f, 2f, 5f, 6f) and the second warp threads (3s, 4s, 7s, 8s) are arranged offset in the weft direction. For example, the first warp thread 2f may be in contact with the second warp thread 3s in the weft direction, but since both are woven into the first weft thread 1'f, they are arranged so as not to overlap in the weft direction. The first warp threads (1f, 2f, 5f, 6f) are also arranged offset in the weft direction, and the second warp threads (3s, 4s, 7s, 8s) are also arranged offset in the weft direction. As a result, eight warp threads are arranged side by side in the weft direction.

The first warp pairs (1f and 2f, 5f and 6f) and the second warp pairs (3s and 4s, 7s and 8s) are arranged alternately in the weft direction. By arranging the first warp pairs and the first warp pairs alternately, the space between the warp and weft threads can be made uniform.

The densities of the first warp threads (1f, 2f, 5f, 6f) and the second warp threads (3s, 4s, 7s, 8s) are in the range of 90% to 140%. Since the warp thread density DW is large, the mesh (gaps) of the industrial fabric 10 are small and the fibers of the nonwoven fabric are less likely to penetrate, resulting in good releasability. The warp thread density DW is calculated by the following formula 1.
DW = (D x M / 25.4) x 100 ... Formula 1
DW is the warp density, D is the diameter of the warp in millimeters, and M is the mesh, which is the number of warp threads per inch. The diameter of the first warp thread and the second warp thread may be the same.

A resin may be applied to the upper surface of the industrial fabric 10 to improve the gripping force. For example, if the gripping force of the industrial fabric 10 is weak, when the nonwoven sheet is transported on the industrial fabric 10, the nonwoven sheet formed may move on the industrial fabric 10 and fold, which may lead to a decrease in the yield rate of the nonwoven sheet. By applying resin to the industrial fabric 10, the gripping force of the industrial fabric 10 is improved. Since the apex of the knuckle of the first warp thread is located closer to the inside of the industrial fabric 10 than the apex of the second warp thread, when applying resin to the industrial fabric 10, the resin attached to the apex of the knuckle of the first warp thread is less likely to come into contact with the press roll of the nonwoven fabric manufacturing machine, and even if the resin attached to the apex of the knuckle of the second warp thread peels off, it is possible to prevent all of the resin from peeling off from the entire industrial fabric 10.

At least some of the second warp threads (3s, 4s, 7s, 8s) are conductive carbon threads. All of the second warp threads (3s, 4s, 7s, 8s) may be conductive carbon threads. By weaving conductive carbon threads into the industrial fabric 10, the industrial fabric 10 can be endowed with static electricity removal properties. If static electricity is charged to the industrial fabric 10, the industrial fabric 10 and the nonwoven web will repel each other, which may prevent a good nonwoven fabric from being formed.

FIG. 4 is a diagram for explaining the loops formed by the second warp thread in the industrial fabric 10. FIG. 4(a) shows the first loop 20a, FIG. 4(b) shows the second loop 20b, and FIG. 4(c) shows the third loop 20c. When there is no need to distinguish between the first loop 20a, the second loop 20b, and the third loop 20c, they are simply referred to as loops 20.

The loop 20 is formed by folding back the warp threads, forming a space for passing the first weft thread, which has a larger diameter. When attaching the industrial fabric 10 to the nonwoven fabric manufacturing device, the worker winds the industrial fabric 10 around multiple rolls and connects both ends of the industrial fabric 10 to form an endless belt. When connecting the ends of the industrial fabric 10, the worker inserts a loop weft thread into the loop 20. The loop weft thread may have the same diameter as the first weft thread, but may also be a smaller diameter than the first weft thread.

In Figure 4, the loop weft to be inserted into the loop 20 is shown in black. If the shape of the loop 20 varies, it becomes difficult to insert the loop weft, and the loop weft is likely to get caught on the loop 20 when being inserted. The width of the industrial textile 10 can be several meters or more, and when inserting a loop weft of that length, it is desirable for the loop 20 to have a regular shape. Also, when the loop weft is inserted into the loop 20, it may get caught on the loop 20, causing the loop 20 to shift or tilt, resulting in partial differences in the breathability of the textile.

The first loop 20a shown in FIG. 4(a) forms a large loop through which two loop wefts (5'r, 7'r) pass by the second warp thread 3s. The second loop 20b shown in FIG. 4(b) forms a large loop through which two loop wefts (5'r, 7'r) pass by the second warp thread 4s. The weft thread 1'f located on the right side of the first loop 20a shown in FIG. 4(a) is a loop weft, and is woven in by folding back a warp thread (not shown). The weft thread 3'f located on the left side of the second loop 20b shown in FIG. 4(b) is a loop weft, and is woven in by folding back a warp thread (not shown).

The third loop 20c shown in FIG. 4(c) is formed by the second warp thread 7s and the second warp thread 8s, forming a small loop through which one loop weft thread passes. The loop weft thread 5'r is inserted into the third loop 20c formed by the second warp thread 7s, and the loop weft thread 7'r is inserted into the third loop 20c formed by the second warp thread 8s. The loops 20 shown in FIG. 4(a) to FIG. 4(c) are arranged in order along the weft direction. This connects both ends of the industrial fabric 10.

FIG. 5 is a diagram for explaining the small loop 22 formed by the first warp thread. The first warp thread 1f is folded back to form the small loop 22. One loop weft thread 5'r is inserted into the small loop 22. The first warp thread 1f is folded back and woven as the first warp thread 2f.

If a loop is formed by a warp thread that is woven with only the second weft, the position of the loop will be at a height that matches the second weft thread located on the upper surface side, and the loop will be formed to protrude above the height of the first weft thread. In the industrial textile 10, all warp threads are woven into the first weft thread with a thick wire diameter, so the loops 20 and small loops 22 are both positioned at the height of the first weft thread, and the loops 20 can be formed well with little variation in position and shape. The stable shape of the loops 20 makes it easier to insert the loop weft thread, and the work of connecting both ends of the industrial textile 10 can be made easier. In addition, the loops 20 are less likely to get caught when the loop weft thread is inserted, which makes it possible to suppress the shifting and tilting of the loops 20, and prevents the formation of marks due to the loops 20 on the nonwoven fabric placed on the loop 20 portion. The stable shape of the loops 20 makes it possible to form large loops.

Note that, as shown in Figures 4(a) to 4(c), the industrial fabric 10 has both a large loop into which two loop wefts can be inserted and a small loop into which one loop weft can be inserted, but is not limited to this embodiment. For example, the industrial fabric 10 may have only a large loop into which two loop wefts can be inserted, or only a small loop into which one loop weft can be inserted.

In the industrial fabric 10, the first warp threads and the second warp threads are arranged in pairs. Therefore, for example, it is possible to form a loop 20 by folding back the second warp thread 3s and weaving it into the adjacent second warp thread 4s.

The weaving patterns of the two first warp pairs are the same, that is, the weaving patterns of the first warp threads 1f and 5f are the same, and the weaving patterns of the first warp threads 2f and 6f are the same, so the inclination direction of the loops is aligned, making it easier to insert the loop weft.

The industrial textiles according to the above-mentioned embodiments may be subjected to the following processing. For example, to improve the smoothness of the surface, the surface side of the industrial textile may be polished to a depth of 0.02 to 0.05 mm. It is particularly preferable for the surface side to be polished to a depth of 0.02 mm or 0.03 mm.

Also, to prevent fraying of the threads at the edge of the net (industrial fabric), the edge may be reinforced by coating it with polyurethane resin within a range of 5 mm to 30 mm (particularly within a range of 5 mm, 10 mm, or 20 mm). The edge of the net may be coated on one or both sides. The resin may be hot-melt polyurethane and may be conductive.

In order to improve the abrasion resistance of the edges of the net, the area 20 mm to 500 mm away from the edge of the net (particularly the area 25, 50, 75, 100, 150, 250, 300, 350, 400 mm away) may be coated over its entire length with 3 to 16 (particularly 3, 4, 7, 8, 10, 12, 15, 16) strips of resin about 7 mm wide. The aforementioned multiple strips of polyurethane resin may be applied to both edges of the net, or only to one side. The resin may be hot-melt polyurethane.

The following lists the ranges of preferred elements for industrial textiles. The diameter of the warp threads (including the first warp thread and the second warp thread) is preferably 0.10 to 1.0 mm, more preferably 0.2 to 0.6 mm, and particularly preferably 0.3 to 0.5 mm. The diameters of the warp threads may be the same. The diameter of the weft threads is preferably 0.10 to 1.2 mm, more preferably 0.2 to 1.0 mm, and particularly preferably 0.4 to 0.9 mm.

The second weft thread may be made of only PET wire, only polyamide wire, or PET wire and polyamide wire woven alternately, or may be a conductive carbon thread. The first weft thread may be made of only PET wire, only polyamide wire, or PET wire and polyamide wire woven alternately, or may be a conductive carbon thread. In addition, a low-friction thread may be woven into the first weft thread to reduce the driving load of the machine.

The air permeability is preferably 100 cm3/cm2/s to 600 cm3/cm2/s, and more preferably 200 cm3/cm2/s to 400 cm3/cm2/s.

The mesh thickness is preferably 0.3 mm to 3.0 mm, more preferably 0.5 mm to 2.5 mm, and particularly preferably 1.0 mm to 2.5 mm. It is mainly used as a nonwoven fabric belt, and may be used in particular as a spunbond nonwoven fabric conveying belt.

The cross-sectional shape of the warp and weft threads in each of the above-mentioned embodiments is not limited to a circle, and threads having a square or star shape, or threads having an elliptical shape, hollow, or core-sheath structure can be used. In particular, by making the cross-sectional shape of the warp threads square, rectangular, or elliptical, the cross-sectional area of the threads can be increased, improving resistance to stretching and rigidity. By making the cross-sectional shape of the second weft threads elliptical or square, there are fewer voids on the surface of the industrial fabric 10 than when the cross-sectional shape is circular, and it is possible to prevent the nonwoven fibers from penetrating the surface of the industrial fabric 10.

The material of the thread can also be freely selected as long as it satisfies the desired characteristics, and examples of materials that can be used include polyethylene terephthalate, polyester, polyamide, polyphenylene sulfide, polyvinylidene fluoride, polypropylene, aramid, polyether ether ketone, polyethylene naphthalate, polytetrafluoroethylene, cotton, wool, metal, thermoplastic polyurethane, and thermoplastic elastomer. Of course, it is also possible to use threads made of copolymers or these materials that are blended with or contain various substances depending on the purpose. In general, it is preferable to use polyester monofilament, which has rigidity and excellent dimensional stability, for the threads that make up industrial textiles.

The present invention relates to industrial fabrics used to manufacture nonwoven fabrics.

1f 1st warp, 1'f 1st weft, 2f 1st warp, 2's 2nd weft, 3s 2nd warp, 3'f 1st weft, 4s 2nd warp, 4's 2nd weft, 5f 1st warp, 5'f 1st weft, 6f 1st warp, 6's 2nd weft, 7s 2nd warp, 7'f 1st weft, 8s 2nd warp, 8's 2nd weft, 10 industrial fabric, 20a 1st loop, 20b 2nd loop, 20c 3rd loop.

Claims (10)

An industrial fabric comprising a first warp thread, a second warp thread, a first weft thread, and a second weft thread,
The first warp thread and the second warp thread are shifted in the weft direction,
The first weft yarn and the second weft yarn are shifted in the warp direction,
The second weft yarn is located on the upper surface side of the industrial fabric,
The first warp yarn is woven only with the first weft yarn,
The second warp yarn is woven with the first weft yarn and the second weft yarn,
A pair of the first warps are adjacent to each other in the weft direction to form a first warp pair,
A pair of the second warps are adjacent to each other in the weft direction to form a second warp pair,
The first weft yarn and the second weft yarn are arranged alternately,
The first warp yarn has a weave pattern that passes under all of the second weft yarns and alternates between above and below the first weft yarns,
The second warp thread forms a weaving pattern in which it passes over one of the first weft threads, one of the second weft threads, and one of the first weft threads, and then passes under one of the second weft threads, one of the first weft threads, one of the second weft threads, one of the first weft threads, one of the second weft threads, one of the first weft threads, and one of the second weft threads. The industrial fabric described in claim 1, characterized in that the first warp yarn pair and the second warp yarn pair are arranged alternately in the weft direction. The industrial fabric according to claim 1 or 2, characterized in that the adjacent first warp threads constituting the first warp thread pair are woven with a warp direction offset from each other by one thread relative to the first weft thread. The industrial fabric according to claim 1 or 2, characterized in that the pair of second warp threads constituting the second warp thread pair are woven with a warp direction offset of two threads from each other relative to the second weft thread. The industrial fabric according to claim 1 or 2, characterized in that in the complete weave forming the repeating pattern of the industrial fabric, the total number of the first warp threads and the second warp threads is eight, and the total number of the first weft threads and the second weft threads is eight. The industrial fabric according to claim 3, characterized in that in the complete weave forming the repeating pattern of the industrial fabric, the weaving patterns of one of the first warp pairs and the other of the first warp pairs are the same. The industrial fabric of claim 1, characterized in that the density of the first warp thread and the second warp thread is in the range of 90 percent to 140 percent. The industrial fabric according to claim 1, characterized in that a resin is applied to the upper surface of the industrial fabric. The industrial fabric according to claim 1, characterized in that at least a portion of each warp thread constituting the first warp thread or the second warp thread is a conductive carbon thread. The industrial fabric according to claim 1, characterized in that the cross-sectional shape of the second weft yarn is elliptical or rectangular.

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