JP6837396B2 - Seam felt base cloth for papermaking - Google Patents

Description

The present disclosure relates to a seam felt base fabric for papermaking having a structure that can be reduced in weight.

Paper felt is used in the press part of paper machines to carry wet paper that is squeezed. The felt for papermaking includes a base cloth and a butt fiber layer formed by needling a short fiber sheet on the base cloth. If the surface of the base cloth is significantly uneven, the pressure acting on the wet paper becomes non-uniform when pressed by the press roll, so that marks (pressure spots) are formed on the manufactured paper and the surface quality of the paper becomes poor. descend. In a seam felt in which loops formed at both ends are hung on each other and both ends are joined by passing a core wire through the hole of the loop, the mark (seam mark) caused by the difference in thickness between the seam part and the ground part. ) Is likely to occur. Therefore, it is desired to suppress the seam mark while ensuring the strength of the seam portion.

For example, Patent Document 1 describes a seam felt base fabric containing one layer of warp yarns and one layer of weft yarns, the base portion is composed of a plain weave, and the seam portion has a loop standing holding region for four weft yarns. The warp threads are arranged one above the other in the portion where the loop is formed. This structure improves the surface properties of the base fabric without significantly changing the thickness and the amount of voids in the base fabric.

Patent Document 2 describes a seam felt base fabric containing one layer of warp threads and two layers of weft threads, loops are created in every other warp threads, and one end side of the warp threads having the loops is at a predetermined position. It is disconnected at. This structure prevents the strength of the seam portion from being significantly reduced, and improves the workability of inserting the loop as compared with the case where the loop is provided in all the warp threads.

Patent Documents 3 and 4 describe a base fabric having a laminated structure in which the base portion is composed of a double weave and the base portion side of the seam portion is composed of a single layer weave. With such a structure, the difference in thickness between the ground portion and the seam portion is reduced, and seam marks, vibrations, and abnormal noise are suppressed.

Japanese Unexamined Patent Publication No. 2008-19521 Japanese Unexamined Patent Publication No. 4-73288 Japanese Unexamined Patent Publication No. 2004-36021 JP-A-2009-144281

In the seam felt base fabric described in Patent Document 1, the seam mark caused by the difference in thickness between the ground portion and the seam portion is alleviated by the loop standing holding region, but the seam mark is single-layered. The difference in thickness was large, and the seam marks were not sufficiently relaxed. In the seam felt base fabric described in Patent Document 2, the seam mark is improved, but the strength of the seam portion may become a problem.

By the way, it is easier to adjust the physical characteristics of felt for papermaking with butt fiber than with base cloth. Further, the wear resistance of the felt is higher when the weight of the butt fiber layer is increased than that of the base cloth. Therefore, we want to increase the number of bats used, but if we simply increase the number of bat fibers, the felt becomes heavier, which affects the power load, or the felt becomes thicker, which causes problems such as poor initial familiarity. Therefore, it is desired to reduce the weight of the base cloth. In order to reduce the weight of the base fabric, it is conceivable to reduce the number of warp or weft. However, in the seam felt base cloth, if the number of warp threads is reduced to reduce the weight of the base cloth, the number of loops is reduced, the load applied to each loop is increased, and the durability is lowered. Therefore, the number of weft threads is reduced to reduce the weight of the seam felt base fabric, but in this case, the frictional force from the weft threads is reduced, which causes a problem that the warp threads are easily pulled out during use of the seam felt.

For example, the base cloth shown in FIG. 8A is composed of two layers of warp threads 1 and one layer of weft threads 2, and the upper layer has three weft threads after the upper warp threads 1a pass under one weft thread 2. The lower layer is woven so that the lower warp threads 1b pass over one weft thread 2 and then under the three weft threads 2. If the number of weft threads 2 per unit length is reduced in such a base fabric, the warp threads 1 can be easily pulled out. Similar to the base fabric shown in FIG. 8 (A), the seam felt base fabric described in Patent Documents 3 and 4 has a warp double structure at the base. Therefore, if the number of weft yarns per unit length is reduced, The warp threads are easily pulled out.

In the base fabric shown in FIG. 8B, the warp yarn 1 is difficult to come off even when the number of weft yarns 2 per unit length is small. This base fabric is composed of one layer of warp threads 1 and two layers of weft threads 2, and the upper weft threads 2a and the lower weft threads 2b are vertically aligned with each other, and the warp threads 1 are the upper weft threads 2a and the lower weft threads 2b. It passes above the upper weft 2a, between the upper weft 2a and the lower weft 2b, and below the lower weft 2b. Further, the other warp threads 1 adjacent to the warp threads 1 are woven so as to be offset by two threads each of the upper weft thread 2a and the lower weft thread 2b. In such a base fabric, the upper weft yarn 2a and the lower weft yarn 2b are separated from each other at the portion where the warp yarn 1 passes between the upper weft yarn 2a and the lower weft yarn 2b aligned vertically, and the base fabric becomes thicker. Therefore, there is a problem that it is compressed in the vertical direction and easily extends in the extending direction of the warp 1, that is, the dimensional stability is low. In the cross-sectional view of the base fabric shown in FIG. 8 (A) along the weft thread 2, the thread shown as the warp thread 1 in FIG. 8 (B) is referred to as the weft thread 2, and the thread shown as the weft thread 2 is used. It corresponds to the figure in which the warp thread 1 is used.

In the base cloth shown in FIG. 8C, the upper weft threads 2a and the lower weft threads 2b do not align with each other in the vertical direction, and the warp threads 1 are placed on one upper weft thread 2a and on one lower weft thread 2b. Under one upper weft 2a, under one lower weft 2b, under one upper weft 2a, under one lower weft 2b, the other warp 1 adjacent to this warp 1 , The upper weft 2a and the lower weft 2b are woven at positions shifted by one each. Such a base fabric has excellent dimensional stability because the thickness change in the vertical direction during pressing is small, but there is a problem that the ground portion is thinner than the seam portion forming the loop and the seam mark becomes prominent. It was. Further, since the interval at which the warp yarn 1 is woven into the upper side of the upper weft yarn 2a and the lower side of the lower weft yarn 2b is short, it is difficult for the number of the warp yarns 1 of the driving yarn to enter, as in the case of the single-layer structure base cloth, and the warp yarn 1 The number has decreased.

In view of these problems, it is an object of the present invention to provide a seam felt base fabric capable of suppressing warp threads from coming off and suppressing seam marks even if the number of weft threads per unit length in the length direction is reduced. And.

Also, when changing the specifications of endless felt using a single-layer (structure consisting of one layer of warp and one layer of weft) base fabric to seam felt, it is necessary to form a loop, so at least seam felt. In the seam part, the warp threads have a double structure. If the entire structure is made up of double warp threads, the base fabric becomes thicker and the weight also increases extremely, so the problem is that the physical properties of seam felt are significantly different from those of felt using the original single-layer structure base cloth. was there. When the seam portion is double warp and the ground portion is single warp and single weft, the seam portion becomes convex, which causes the occurrence of seam marks. The present invention also solves such a problem.

In the seam felt base fabric for papermaking according to at least some embodiments of the present invention, a seam portion (17) including a loop (16) formed by folding back the warp yarn (13) and the warp yarn are woven into the weft yarn. A seam felt base cloth (10) for papermaking provided with a base portion (15), wherein the warp yarn composed of one layer includes a first warp yarn (13a) woven into the weft yarn in a predetermined pattern and the first warp yarn. The two-layered weft contains a second warp (13b) woven into the weft in a pattern different from that of the warp, and includes an upper weft (14a) and a lower weft (14b). The weaving pattern from one side to the other side of the weft matches the weaving pattern of the second warp from the other side to the one side of the weft, so that the upper weft and the lower weft are brought together. The feature is that they are arranged so as not to be aligned vertically with each other.

According to this configuration, the frictional force applied from the weft to the warp is larger than that of the structure in which the warp is composed of two layers, and even if the number of warp threads is reduced per unit length, the warp can be prevented from coming off. Further, since the upper weft and the lower weft are not aligned with each other in the vertical direction, the thickness in the vertical direction is thinner than the case where the upper weft and the lower weft are aligned with each other in the vertical direction, and one layer is used. Since the thickness in the vertical direction is thicker than that of the base cloth composed of the warp and the weft of one layer, the thickness of the base portion becomes close to the thickness of the seam portion, and the seam mark is suppressed. In addition, since the marks on the ground are weft-like, the weft-like marks extend in the machine direction (transverse direction) and become blurred in the paper manufacturing process, so that the marks generated on the paper are inconspicuous.

The seam felt base fabric for papermaking according to at least some embodiments of the present invention is characterized in that, in the above configuration, the first warp and the second warp in the complete structure are the same number of each other.

According to this configuration, the force applied from the warp to the weft is not biased as a whole, so that the arrangement in which the upper weft and the lower weft are not vertically aligned with each other is stable.

In the above configuration, the seam felt base fabric for papermaking according to at least some embodiments of the present invention has the complete structure of four first warp threads, four second warp threads, and four said complete warp threads. It is composed of an upper weft and four lower wefts, and the upper weft and the lower weft are arranged alternately with each other in a plan view. In the complete structure, the first warp is one upper weft. Is woven, and one lower weft corresponding to the third weft is woven from the woven upper weft toward one side, and each of the first warp is different from each other. And one of the lower wefts are woven, and the second warp is one that corresponds to the third weft from the woven upper weft toward the other side. The lower weft yarn is woven, and each of the second warp yarns is woven with one upper weft yarn and one lower weft yarn that are different from each other.

According to this configuration, the forces from the warp threads applied to the upper weft threads and the lower weft threads become equal as a whole, and the distance between the upper weft threads and the lower weft threads adjacent to each other becomes substantially constant.

The seam felt base fabric for papermaking according to at least some embodiments of the present invention is characterized in that, in the above configuration, the first warp and the second warp are alternately arranged every four in a plan view. To do.

According to this configuration, since the warp yarns weave the upper weft yarns from above, the unevenness generated on the papermaking surface side is dispersed, so that the marks generated on the manufactured paper can be suppressed.

According to the present invention, even if the number of weft yarns per unit length in the length direction is reduced, it is possible to provide a seam felt base fabric capable of suppressing the slipping out of warp yarns and suppressing seam marks.

Perspective view of seam felt according to the embodiment Organizational chart of seam felt base fabric according to the embodiment Schematic cross-sectional view of the seam felt base fabric according to the embodiment Cross-sectional photograph of seam felt base cloth according to an embodiment Photographs showing the results of pressure distribution measurement of the seam portion of the seam felt base cloth according to the examples (A: Comparative Example 1 (double woven base cloth), B: Example, C: Comparative Example 2 (single woven base cloth) ))) Photograph of the seam part of the seam felt base cloth according to the embodiment Photograph showing the result of pressure distribution measurement of the ground part of the seam felt base cloth according to the example (A: Comparative example, B: Example) Schematic cross-sectional view of the seam felt base fabric according to the prior art The figure explaining the state of the pull-out test of the warp

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a papermaking seam felt 11 including a papermaking seam felt base cloth 10 (hereinafter, referred to as “base cloth 10”) according to the embodiment. The seam felt 11 for papermaking includes a base cloth 10 and a butt fiber layer 12 formed by needling a short fiber sheet of a synthetic resin such as polyamide, polyester, polyethylene, polypropylene, or polyvinyl chloride to the base cloth 10.

As shown in FIGS. 1 and 2, the base cloth 10 has a base portion 15 in which the warp yarn 13 is woven into the weft yarn 14, and a seam portion 17 including a loop 16 formed by folding back the warp yarn 13. The seam felt 11 for papermaking is made endless by engaging and joining loops 16 provided at both ends, and the inner (running surface side) surface thereof is supported by a roll (not shown) of a paper machine. , Its outer (papermaking surface side) surface supports the wet paper.

As shown in FIGS. 2 and 3, the warp 13 extending in the machine direction is composed of one layer, and the weft 14 extending in the machine crossing direction is the upper weft 14a arranged on the papermaking surface side and the traveling surface side. Includes a bobbin thread 14b arranged in. The upper weft threads 14a and the lower weft threads 14b are arranged in the same number as each other and are alternately arranged in a plan view so as not to be vertically aligned with each other, that is, at positions displaced from each other in the mechanical direction. The complete structure of the base cloth 10 is composed of eight warp threads 13 and eight weft threads 14, and the No. 1 in FIGS. 2 and 3 is formed. The wefts 14 of 2, 4, 6 and 8 are upper wefts 14a, and No. The wefts 14 of 1, 3, 5 and 7 are the lower wefts 14b.

The warp 13 includes a first warp 13a woven into the weft 14 in a predetermined pattern, and a second warp 13b woven into the weft 14 in a pattern different from the first warp 13a. The number of the first warp threads 13a and the second warp threads 13b is the same as that of the first warp threads 13a, and four first warp threads 13a are continuously arranged in a plan view, and then four second warp threads 13b are continuously arranged. No. in FIGS. 2 and 3 The warp threads 13 of 5'to 8'are the first warp threads 13a, and No. The warp 13 of 1'to 4'is the second warp 13b. The method of weaving the first warp 13a into the weft 14 and the method of weaving the second warp 13b into the weft 14 form a mirror image symmetrical shape with respect to a predetermined cross section orthogonal to the machine direction. That is, the weaving pattern from the upstream side (the other side) of the first warp 13a toward the weft 14 to the downstream side (one side) is the downstream side (one side) of the second warp 13b to the weft 14. ) To the upstream side (the other side). Here, the downstream side means the direction of travel, and the upstream side means the opposite side.

Specifically, No. The first warp thread 13a of 5'is No. On top of 8, No. On top of 1, No. Under 2, No. Under 3, No. Under 4, No. No. 5 above. Under 6, No. It is woven into the weft 14 so as to pass over the 7. No. The second warp 13b of 1'is No. No. 8 with respect to the cross section orthogonal to the machine direction passing through the upper weft thread 14a. It is woven into the weft 14 by the weaving pattern of the first warp 13a of 5'and the mirror-symmetrical weaving pattern. On top of 8, No. On top of 7, No. Under 6, No. Under 5, No. Under 4, No. No. 3 above. Under 2, No. It is woven into the weft 14 so as to pass over 1.

No. The first warp threads 13a of 6', 7'and 8'are No. 1 respectively. 6, 2 and 4 wefts 14 (3, 1 and 2 upper wefts 14a) are downstream of the 1st warp 13a of 5'(FIGS. 2 and 2). At a position shifted to the traveling direction side of No. 3), No. It is woven into the weft 14 in the same pattern as the first warp 13a of 5'. No. The second warp threads 13b of 2', 3'and 4'are No. 1 respectively. At a position shifted downstream by 6, 2 and 4 wefts 14 (3, 1 and 2 upper wefts 14a) with respect to the 1'second warp 13b. , No. It is woven into the weft 14 in the same pattern as the second warp 13b of 1'. No. The positions of the first warp threads 13a of 5'to 8'may be interchanged with each other. The positions of the second warp threads 13b of 1'to 4'may be interchanged with each other.

Since the weaving pattern itself of the first warp 13a does not have a mirror image symmetrical shape with respect to the cross section orthogonal to the machine direction, the force applied from the first warp 13a to the weft 14 is biased, and the first warp 13a alone is superior. The weft 14a and the lower weft 14b cannot be stabilized at positions displaced from each other in the mechanical direction. Therefore, the second warp 13b, which constitutes a mirror-symmetrical weaving pattern with respect to the weaving pattern of the first warp 13a, is woven, and a force biased in the direction opposite to that of the first warp 13a is applied to the weft 14 to move up. The weft 14a and the lower weft 14b are stabilized at positions displaced from each other in the mechanical direction. In other words, since the first warp 13a and the second warp 13b are mirror-symmetrical to each other, the duality in which the upper weft 14a and the lower weft 14b are vertically aligned with each other is broken. The number of the first warp 13a and the second warp 13b are the same as each other, and No. The first warp threads 13a of 5 to 8 are displaced from each other and woven into the weft thread 14, and No. Since the second warp threads 13b of 1 to 4 are displaced from each other and woven into the weft threads, the displacement between the upper weft threads 14a and the lower weft threads 14b becomes substantially even.

Due to the collapse of the duality of the upper weft 14a and the lower weft 14b, the ground portion 15 has a structure that maintains the duality of the upper weft 2a and the lower weft 2b shown in FIGS. 8A and 8B. getting thin. Further, since there are more warp threads 13 passing between the upper and lower weft threads 14a and 14b than the structure shown in FIG. 8 (C), the ground portion 15 is thicker than the structure shown in FIG. 8 (C). Therefore, the thickness of the ground portion 15 becomes close to the thickness of the seam portion 17. Further, when the base cloth 10 is made by bag weaving using the weft 14 as the warp and the warp 13 as the driving thread, the warp 13 passes over the upper weft 14a and the lower weft 14b rather than the structure shown in FIG. 8C. Since the interval passing underneath is long, it becomes easy for the driving thread to enter.

In the ground portion 15, since the warp threads 13 are sandwiched between the upper and lower weft threads 14a and 14b more than the structure shown in FIG. 8 (A), the frictional force applied from the weft threads 14 to the warp threads 13 is large, and the warp threads 13 are suppressed from coming off. Will be done. Therefore, even if the number of warp threads 13 per unit length is not reduced, the number of weft threads 14 per unit length can be reduced to reduce the weight of the base cloth 10, and the warp threads 13 can be removed while maintaining the joint strength of the loop 16. Can be suppressed.

Further, in the ground portion 15, since the upper weft thread 14a and the lower weft thread 14b are positioned so as to be offset from each other in the machine direction, the compressibility in the vertical direction is lower than that of the structure shown in FIG. 8 (B). Therefore, the elasticity in the machine direction is also low, and the dimensional stability is excellent.

Further, in a plan view, the first warp threads 13a and the second warp threads 13b are alternately arranged every four, so that the warp threads 13 weave the upper weft threads 14a from above to disperse the unevenness generated on the papermaking surface side. , Marks generated on the manufactured paper can be suppressed.

As the warp 13 and the weft 14, monofilament single yarn or twisted yarn can be used, and the material thereof is preferably a synthetic resin such as nylon, polyamide, polyester, polyethylene, polypropylene, or polyvinyl chloride. The diameter of the warp 13 is preferably 0.29 mm to 0.39 mm, and the diameter of the weft 14 is preferably 0.29 mm to 0.42 mm. The number of warp threads 13 per unit length is preferably 18.1 threads / cm to 22.8 threads / cm (46 threads / inch to 58 threads / inch). When the number of warp threads 13 per unit length is such, the number of weft threads 2 of the base cloth according to the prior art is approximately 15.7 threads / cm to 23.6 threads / cm (40 threads). Although it is / inch to 60 threads / inch, the number of weft threads 14 of the base cloth 10 according to the present embodiment is 11.8 threads / cm to 18.1 threads / cm (30 threads / inch). ~ 46 lines / inch). The thickness of the ground portion 15 is 0.9 mm to 1.4 mm.

Using the warp 13 and the weft 14 having a diameter of 0.35 mm, the base cloth 10 (Example) corresponding to the above embodiment and the base cloth corresponding to FIG. 8 (A) as a comparative example (warp double structure, Comparative Example). 1) A base cloth having a single structure (Comparative Example 2) and a base cloth corresponding to FIG. 8 (C) (Comparative Example 3) were prepared. The thickness of the examples was 1.25 mm, which was substantially equal to the thickness of the seam portion 17. The thicknesses of Comparative Examples 1 to 3 were 1.35 mm, 0.8 mm and 0.95 mm, respectively.

FIG. 4 shows a photograph of the above embodiment cut in a cross section orthogonal to the machine transverse direction. The upper weft thread 14a and the lower weft thread 14b were stable in a state of being displaced from each other in the mechanical direction.

A felt test piece having a base cloth of Comparative Example 1, a felt test piece having a base cloth of Example, and a felt test piece having a base cloth of Comparative Example 2 were prepared, and loops at both ends were made of each other. The pressure distribution of the seam in the joined state was measured. FIG. 5 is a photograph showing the results (A: Comparative Example 1, B: Example, C: Comparative Example 2). In the figure, the portion extending to the left and right in the center of the vertical direction of the paper surface corresponds to the seam portion, and the dark-colored portion indicates the portion where the pressure is high. It is shown that the higher the pressure difference between the ground portion and the seam portion, that is, the larger the shade difference in FIG. 5, the stronger the seam mark is generated. In Comparative Example 1 shown in FIG. 5 (A), the pressure of the seam portion was low because the thickness of the ground portion was thicker than the thickness of the seam portion. In Comparative Example 2 shown in FIG. 5C, on the contrary, the pressure of the seam portion was high because the thickness of the ground portion was thinner than the thickness of the seam portion. In the embodiment shown in FIG. 5 (B), the thickness of the ground portion 15 was substantially the same as that of the seam portion 17, so that the pressures of both were substantially equal. FIG. 6 is a photograph of the seam portion 17 of the base cloth 10 according to the embodiment.

The pressure distribution was measured on the ground portion of the felt test piece having the base cloth of Comparative Example 1 and the felt test piece having the base cloth of Example 1. FIG. 7 is a photograph showing the result (A: Comparative Example 1, B: Example). The vertical and horizontal directions of the paper surface are the extending directions of the warp threads 1, 13 and the weft threads 2, 14, respectively. The mark of Comparative Example 1 was transmuscular. On the other hand, the marks of the examples were weft-like. In the process of papermaking, the manufactured paper stretches in the machine direction and becomes thinner, so that the weft-like marks are blurred and inconspicuous as compared with the trans-streak-like marks. Therefore, the paper produced by using the felt having the base cloth according to the embodiment has less conspicuous marks than the paper produced by using the felt having the base cloth according to Comparative Example 1.

For Examples and Comparative Examples 1 to 3, a warp pull-out test was performed to compare the ease of pulling out the warp threads 1 and 13. As shown in FIG. 9, a test piece obtained by cutting the warp threads 1 and 13 at one place in advance is set in a tensile tester, and one warp thread 1 and 13 is pulled at a stroke speed of 100 mm / cm to pull the warp threads 1 and 13 at a stroke speed of 100 mm / cm. The load when 13 was pulled out or cut was measured. The results are shown in Table 1. In Comparative Example 1, the warp 1 was pulled out at 27.0 N / line, but in Examples and Comparative Examples 2 and 3, the warp threads 1 and 13 were not pulled out and were cut at 40.0 to 43.0 N / line. That is, the warp thread 13 of the example was more difficult to pull out than the warp thread 1 of the comparative example 1, and showed the same difficulty of pulling out as the warp thread 1 of the comparative examples 2 and 3.

Although the description of the specific embodiment is completed above, the present invention can be widely modified without being limited to the above embodiment. For example, the number of wefts included in the complete structure may be increased, and the number of wefts between the position where the warp weaves the upper weft from above and the position where the warp weaves the lower weft from below may be increased. Further, the first warp and the second warp may be arranged one by one or two by two, and the number of warp threads included in the complete tissue may be increased or decreased. Further, the number of the first warp and the second warp in the complete structure may be different from each other.

10: Papermaking seam felt base cloth 11: Papermaking seam felt 12: Butt fiber layer 13: Warp 13a: First warp 13b: Second warp 14: Weft 14a: Upper weft 14b: Lower weft 15: Base 16: Loop 17: Seam part

Claims (4)

A seam felt base fabric for papermaking, comprising a seam portion including a loop formed by folding back the warp threads and a base portion in which the warp threads are woven into the weft threads.
The warp composed of one layer includes a first warp woven into the weft in a predetermined pattern and a second warp woven into the weft in a pattern different from the first warp.
The two-layered weft includes an upper weft and a lower weft.
The weaving pattern of the first warp from one side to the other of the weft matches the weaving pattern of the second warp from the other side to the one side of the weft to match the upper weft. A seam felt base fabric for papermaking, characterized in that the lower weft threads are arranged so as not to be aligned vertically with each other. The seam felt base fabric for papermaking according to claim 1, wherein the first warp and the second warp in the complete structure have the same number of each other. The complete structure is composed of four first warp threads, four second warp threads, four upper weft threads, and four lower weft threads.
The upper weft and the lower weft are arranged alternately with each other in a plan view.
In the complete structure, the first warp weaves one upper weft, and one lower weft corresponding to the third weft toward one side from the woven upper weft. Weaving, each of the first warp yarns weaves one upper weft yarn and one lower weft yarn different from each other, and the second warp yarn weaves one said upper weft yarn and weaves the upper weft yarn. Weaving one lower weft corresponding to the third weft toward the other side, and each of the second warp weaving one upper weft and one lower weft that are different from each other. The seam felt base cloth for papermaking according to claim 2, which is characterized. The seam felt base cloth for papermaking according to claim 3, wherein the first warp and the second warp are alternately arranged every four in a plan view.