Base fabric for papermaking seam felt

Abstract

To provide a seam felt for paper making in which a portion of the warp yarn folded to form a loop is difficult to be pulled out from the fabric part.SOLUTION: A seam felt base fabric 2 for paper making of the invention is provided with weft yarn 6 including upper weft yarn 8 and lower weft yarn 9, and warp yarn 7 into which the weft yarn 6 is interwoven. The seam felt base fabric 2 for paper making is also provided with a loop section 5 including a loop 4 and a fabric part 10 in which the warp yarn 7 is interwoven with the weft yarn 6. The loop 4 is formed by folding the warp yarn 7, and a folded portion 13 is woven into the fabric part 10. The folded portion 13 forms a larger structure of crimps than the portion positioned in the center of the warp direction above a mating point 14. The larger crimped structure prevents the folded portion 13 from coming out in the warp yarn 7.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a base fabric for a papermaking seam felt.

Background Art

[0002] A papermaking seam felt is used in a press part such as a paper machine or a pulp machine, and conveys wet paper to be dewatered. For a papermaking seam felt, wet paper transportability, dewatering property, surface property (paper surface property) that does not mark the surface of the paper, initial adaptability regarding the time until it reaches a preferable state after being mounted on a paper machine or the like, antifouling property, and durability are required. When a papermaking seam felt is attached to a paper machine or the like, loops provided at both ends are hooked together, and a core wire is inserted into the loop and joined to form an endless shape.

[0003] As one method for forming loops in a base fabric for a papermaking seam felt, after weaving the base fabric in a flat plate shape (having ends in the warp direction), the warp threads are folded back to form loops, and the folded-back portions are woven into the ground part (for example, Patent Document 1). Note that loops of a dryer canvas used in the dryer part of a paper machine may also be formed by the same method (for example, Patent Documents 2 and 3).

[0004] In the invention described in Patent Document 1, the joints between the folded-back portions for forming loops and other warp threads include portions where both threads overlap each other (aligned portions) and butting portions, and are scattered. In the invention described in Patent Document 2, the joints (thread raising cut portions) are such that both threads overlap by a length of two weft threads, and these are dispersed. In the invention described in Patent Document 3, the joints are formed by butting both threads, and two adjacent joints in the weft direction are displaced in the warp direction.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the base fabric formed in this way, there was a problem that the folded part for forming loops in the warp was likely to come out from the ground part.

[0007] In view of the above background, an object of the present invention is to provide a papermaking seam felt in which the folded part for forming loops in the warp is difficult to come out from the ground part.

Means for Solving the Problems

[0008] In order to solve the above problems, an aspect of the present invention provides a papermaking seam felt base fabric (2, 21) comprising a weft yarn (6) including an upper weft yarn (8) extending in the weft direction and a lower weft yarn (9) disposed on the running surface side of the upper weft yarn (8) and extending in the weft direction, and warp yarns (7) extending in the warp direction into which the weft yarn (6) is woven. The weft yarn (6) includes a ground portion (10, 22) into which the warp yarn (7) is woven, and loop portions (5) protruding from both ends of the ground portion (10, 22) in the warp direction. The loop portion (5) includes a plurality of loops (4) formed by folding back the warp yarn (7). In a pair of the warp yarns (7) arranged to form two warp yarn rows connected by the loops (4) near the ends in the warp direction, one of the pair of warp yarns (7) is folded back to form the loop (4), and the tip-side end of the folded-back portion (13, 23) of the one and the other end of the pair of warp yarns (7) are arranged to overlap or abut each other when viewed in the weft direction in the ground portion (10, 22), thereby forming a joint (14). In the pair of warp yarns (7), at least a part of the folded-back portion (13, 23) of the one forms a structure with a larger crimp than a portion arranged more centrally in the warp direction than the joint (14).

[0009] According to this aspect, by forming a structure with a larger crimp in at least a part of the folded-back portion than a portion arranged more centrally in the warp direction than the joint, it is possible to suppress the detachment of the folded-back portion from the ground portion with little change in the paper surface property.

[0010] In the papermaking seam felt base fabric (2) of the above aspect, the ground portion (10) includes end ground portions (11) disposed adjacent to each of the loop portions (5) and a main ground portion (12) disposed between the two end ground portions (11). The joint (14) is formed in the main ground portion (12), and the warp yarns (7) in the end ground portions (11) may form a structure with a larger crimp than the warp yarns (7) in the main ground portion (12).

[0011] According to this aspect, since the weft yarns in the end ground portion firmly hold the warp yarns forming loops on both sides, the effect of suppressing the slipping of the warp yarns is enhanced.

[0012] In the papermaking seam felt base fabric (2) of the above aspect, the length between the weft yarns (6) arranged at both ends in the warp direction in the end ground portion (11) may be 5 to 7 cm.

[0013] The main ground portion is superior in paper surface property to the end ground portion, and the end ground portion is stronger in resistance to the slipping of the warp yarns than the main ground portion. According to this aspect, the balance between suppressing the slipping of the warp yarns and suppressing the deterioration of the paper surface property is improved.

[0014] In the papermaking seam felt base fabric (21) of the above aspect, in the ground portion (22), the portion excluding the joint (14) in the folded-back portion (23) may form a structure with a larger crimp than the other portions in one pair of the warp yarns (7).

[0015] According to this aspect, since the resistance to slipping becomes large only for the folded-back portion where slipping is likely to occur, the slipping of the warp yarns is suppressed and the deterioration of the paper surface property is suppressed.

[0016] In the papermaking seam felt base fabric (2, 21) of the above aspect, the weft yarns (6) may be arranged at 13.8 to 17.7 per 1 cm in the warp direction.

[0017] According to this aspect, the balance among water squeezing property, paper surface property, and durability is improved.

[0018] In the papermaking seam felt base fabric (2, 21) of the above aspect, the joint (14) may be formed by the ends of the one folded-back portion (13, 23) and the other end overlapping by 5 to 13 weft yarns as viewed in the weft direction.

[0019] According to this aspect, a frictional force acts between the warp threads that overlap each other, suppressing the slipping of the warp threads from the weft threads at the portion where the alignment marks in the warp threads are formed.

[0020] In the seam felt base fabric (2, 21) for papermaking of the above aspect, in the vicinity of each end portion in the warp direction, the alignment marks (14) may be arranged at a distance of 250 or more weft threads (6) from the loop portion (5).

[0021] According to this aspect, since the alignment marks are arranged at a distance of 250 or more weft threads from the loop portion, the folded portion is woven into the weft threads with a length of a predetermined value or more, enhancing the effect of suppressing the slipping of the warp threads.

[0022] In the seam felt base fabric (2, 21) for papermaking of the above aspect, in the vicinity of each end portion in the warp direction, the alignment marks (14) adjacent to each other in the weft direction may be arranged such that the closest portions of each other are separated from each other by a distance of 17 or more weft threads (6) in the warp direction.

[0023] According to this aspect, since the alignment marks where the warp threads are densely arranged are dispersed, a decrease in paper surface quality and water squeezing performance is suppressed.

[0024] In the seam felt base fabric (2, 21) for papermaking of the above aspect, the ratio of the number of upper weft threads (8) to the number of lower weft threads (9) is 1:1, and the upper weft threads (8) and the lower weft threads (9) may be alternately arranged at positions shifted from each other in the warp direction.

[0025] According to this aspect, compared with the case where the upper weft threads and the lower weft threads are aligned in the thickness direction, the thickness change in the thickness direction becomes smaller, so the stretchability in the warp direction becomes lower and the dimensional stability is excellent.

Effect of the Invention

[0026] According to the above aspects, it is possible to provide a seam felt for papermaking in which the portion folded to form a loop in the warp threads is difficult to slip out from the ground portion.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 7 show the first embodiment.

[0029] FIG. 1 is a perspective view of a papermaking seam felt 1. The papermaking seam felt 1 includes a papermaking seam felt base fabric 2 (hereinafter referred to as "base fabric 2") and a batt fiber layer 3 formed by needling a short fiber sheet of a synthetic resin such as polyamide, polyester, polyethylene, polypropylene, or polyvinyl chloride onto the base fabric 2. A loop portion 5 including a plurality of loops 4 is formed at an end portion in the warp direction of the base fabric 2. The papermaking seam felt 1 is used in the press part of a paper machine. By hooking the loops 4 provided at both ends together and inserting and joining a core wire into the loops, it is made endless. The inner (running surface side) surface thereof is supported by a roll (not shown) of the paper machine, etc., and the outer (paper-making surface side) surface thereof supports wet paper.

[0030] As shown in FIG. 2, the base fabric 2 includes a plurality of weft yarns 6 extending in the weft direction and a plurality of warp yarns 7 extending in the warp direction and into which the weft yarns 6 are woven. The "warp direction" is the length direction of the base fabric 2 and coincides with the running direction (machine direction) of the machine when attached to the paper machine. The "weft direction" is the width direction of the base fabric 2 and coincides with the direction (cross machine direction) perpendicular to the machine direction along the plane of the base fabric 2 when attached to the paper machine. The weft yarns 6 are arranged at 13.8 to 17.7 per 1 cm in the warp direction (35 to 45 per 1 inch) ("x to y" means x or more and y or less, the same hereinafter). The warp yarns 7 are arranged at 18.1 to 22.8 per 1 cm in the weft direction (46 to 58 per 1 inch).

[0031] The weft yarns 6 include a plurality of upper weft yarns 8 arranged on the paper-making surface side and a plurality of lower weft yarns 9 arranged on the running surface side. The ratio of the number of upper weft yarns 8 to the number of lower weft yarns 9 is 1:1. When viewed from the thickness direction (the direction perpendicular to the warp direction and the weft direction) of the base fabric 2, the upper weft yarns 8 and the lower weft yarns 9 are alternately arranged at positions shifted from each other in the warp direction. Each warp yarn 7 is woven into the upper weft yarns 8 and the lower weft yarns 9. Such a fabric in which two layers of weft yarns 6 in the upper and lower layers weave one layer of warp yarns 7 is sometimes called a warp single weft double weave.

[0032] The base fabric 2 includes a ground portion 10 where the weft yarns 6 interweave with the warp yarns 7, and two loop portions 5 protruding from both ends of the ground portion 10 in the warp direction. The loop portion 5 includes a loop 4 formed by folding back the warp yarn 7, and does not include the weft yarn 6. The ground portion 10 includes two end ground portions 11 disposed adjacent to each of the loop portions 5, and a main ground portion 12 disposed between the two end ground portions 11. The complete weave of the end ground portion 11 is composed of three upper weft yarns 8, three lower weft yarns 9, and three warp yarns 7. The complete weave of the main ground portion 12 is composed of four upper weft yarns 8, four lower weft yarns 9, and eight warp yarns 7. Note that the weft yarn No. and warp yarn No. in the figure, those with a single quote in the number (1', 2', ···) correspond to the weft yarn 6 and warp yarn 7 of the end ground portion 11, and those with only a number (1, 2, ···) correspond to the weft yarn 6 and warp yarn 7 of the main ground portion 12.

[0033] The loop 4 of the loop portion 5 is formed by folding back the warp yarns 7 that constitute the warp yarn series of warp yarn No. 8, 2, 4, and 6 near the end of the base fabric 2. The folded portion 13 is woven into the ground portion 10 within a predetermined range from the loop 4 and constitutes a part of the warp yarn series of warp yarn No. 1, 3, 5, and 7. For the opposite end, although not shown, the loop 4 is formed in the same manner.

[0034] Note that the loop 4 on the opposite side may be formed by folding back the warp yarns 7 that constitute the warp yarn series of warp yarn No. 1, 3, 5, and 7, and the folded portion 13 may constitute the warp yarn series of warp yarn No. 8, 2, 4, and 6 within a predetermined range from the loop 4. Also, the loop 4 on the opposite side may be formed by folding back the warp yarns 7 that constitute the warp yarn series of warp yarn No. 8, 2, 4, and 6, and the folded portion 13 may constitute the warp yarn series of warp yarn No. 7, 1, 3, and 5 within a predetermined range from the loop 4. Also, the loop 4 on the opposite side may be formed by folding back the warp yarns 7 that constitute the warp yarn series of warp yarn No. 1, 3, 5, and 7, and the folded portion 13 may constitute the warp yarn series of warp yarn No. 2, 4, 6, and 8 within a predetermined range from the loop 4.

[0035] Refer to FIGS. 2(A), 3, and 7(B). The length of the end ground portion 11 in the warp direction, that is, the length between the weft yarns 6 arranged at both ends in the warp direction at the end ground portion 11, is 5 to 7 cm. For convenience of illustration, in FIGS. 2(A) and 3, only 12 weft yarns 6 are shown in the end ground portion 11, but the actual number of weft yarns 6 is much larger. In the end ground portion 11, the weft yarn rows of weft yarns No. 1', 3', and 5' are composed of the lower weft yarns 9, and the weft yarn rows of weft yarns No. 2', 4', and 6' are composed of the upper weft yarns 8. The warp yarn 7 of warp yarn No. 1' passes through the weft yarns 6 of weft yarns No. 1' to 6' in the order of down, down, up, up, up, down. The warp yarn 7 of warp yarn No. 2' is shifted by two weft yarns 6 (one upper weft yarn 8 or lower weft yarn 9) in the direction of the smaller weft yarn No. relative to the warp yarn 7 of warp yarn No. 1' and is woven into the weft yarn 6. The warp yarn 7 of warp yarn No. 3' is shifted by two weft yarns 6 in the direction of the larger weft yarn No. relative to the warp yarn 7 of warp yarn No. 1' and is woven into the weft yarn 6.

[0036] Refer to FIGS. 2(B), 4, and 7(C). In the main ground portion 12, the weft yarn rows of weft yarns No. 1, 3, 5, and 7 are composed of the upper weft yarns 8, and the weft yarn rows of weft yarns No. 2, 4, 6, and 8 are composed of the lower weft yarns 9. The warp yarn 7 of warp yarn No. 1 passes through the weft yarns 6 of weft yarns No. 1 to 8 in the order of down, down, down, up, up, up, down, up. The warp yarn 7 of warp yarn No. 2 is shifted by two weft yarns 6 in the direction of the larger weft yarn No. relative to the warp yarn 7 of warp yarn No. 1 and is woven into the weft yarn 6. The warp yarn 7 of warp yarn No. 3 is shifted by two weft yarns 6 in the direction of the smaller weft yarn No. relative to the warp yarn 7 of warp yarn No. 1 and is woven into the weft yarn 6. The warp yarn 7 of warp yarn No. 4 is shifted by four weft yarns 6 relative to the warp yarn 7 of warp yarn No. 1 and is woven into the weft yarn 6.

[0037] The weft insertion pattern of the warp threads 7 of warp threads No. 5 to 8 forms a mirror symmetry with respect to a predetermined cross-section orthogonal to the warp direction with respect to the weft insertion pattern of the warp threads 7 of warp threads No. 1 to 4. The warp thread 7 of No. 5 passes through the weft threads 6 of weft threads No. 1 to 8 in the order of down, up, down, up, up, up, down, down. The warp thread 7 of warp thread No. 6 is woven into the weft thread 6 by shifting by two weft threads 6 in the direction of the larger weft thread number with respect to the warp thread 7 of warp thread No. 5. The warp thread 7 of warp thread No. 7 is woven into the weft thread 6 by shifting by two weft threads 6 in the direction of the smaller weft thread number with respect to the warp thread 7 of warp thread No. 5. The warp thread 7 of warp thread No. 8 is woven into the weft thread 6 by shifting by four weft threads 6 with respect to the warp thread 7 of warp thread No. 5.

[0038] Refer to FIGS. 2(B) and 4. Focusing on a pair of warp threads 7 arranged to form two warp thread rows connected by loops 4 near the end in the warp direction, one of the pair of warp threads 7 (warp threads No. 8, 2, 4, 6) is folded back to form a loop 4, and the portion on the tip side of the folded portion 13 beyond the loop 4 is woven into the ground portion 10. The tip-side end of this folded portion 13 and the end of the other of the pair of warp threads 7 (warp threads No. 1, 3, 5, 7) are arranged so as to overlap when viewed in the weft direction in the main ground portion 12 (woven into the weft thread 6 of the common weft thread No.), and a joint 14 (the portion surrounded by a broken line in the figure) is formed. In the joint 14 in the illustrated example, both ends overlap by five weft threads 6 when viewed in the weft direction, but this number may be changed, and it is preferable that they overlap by 5 to 13 weft threads 6. Also, the joint 14 is preferably arranged at a distance of 250 or more weft threads 6 in the warp direction from the loop portion 5. Also, the joints 14 adjacent to each other in the weft direction are preferably arranged so that the closest portions to each other are separated from each other by a distance of 17 or more weft threads 6 in the warp direction.

[0039] The warp 7 in the end ground part 11 forms a structure with a larger crimp than the warp 7 in the main ground part 12. Referring to FIG. 5, the "structure with a large crimp" in the warp 7 will be described. FIG. 5(A) shows a comparative example, FIG. 5(B) shows the end ground part 11, and FIG. 5(C) shows the main ground part 12. In a predetermined section, the larger the value obtained by dividing the lengths LA, LB, and LC of the warps 7 and 107 including a curved shape by the linear distance L in the extending direction (warp direction) of the warps 7 and 107 in that section, the "larger the crimp" is said to be. In FIG. 5(A), in the section of the distance L, the pattern in which the warp 107 passes over the upper weft 108, then passes under the lower weft 109, and then passes over the upper weft 108 again is repeated 1 + 5 / 8 times. Also, since the upper weft 108 and the lower weft 109 are vertically aligned with each other, the thickness of the ground part 110 is larger than that shown in FIGS. 5(B) and (C), and the length LA of the warp 107 also becomes larger accordingly. In FIG. 5(B), in the section of the distance L, the pattern in which the warp 7 passes over the upper weft 8, then passes under the lower weft 9, and then passes over the upper weft 8 again is repeated 2 + 1 / 6 times. In FIG. 5(C), in the section of the distance L, the same pattern is repeated 1 + 5 / 8 times. Therefore, LB > LA > LC and LB / L > LA / L > LC / L. That is, the warp 7 of the end ground part 11 shown in FIG. 5(B) forms the structure with the largest crimp, the warp 107 of the comparative example shown in FIG. 5(A) forms the structure with the second largest crimp, and the warp 7 of the main ground part 12 shown in FIG. 5(C) forms the structure with the smallest crimp. Note that the "structure with a large crimp" for the warp 7 can be rephrased as "the bending angle of the warp 7 at the knuckle part where the warp 7 weaves in the weft 6 is small".

[0040] Referring to FIG. 6, the inclination of loop 4 will be described. FIG. 6(A) shows loop 104 according to a comparative example, and FIG. 6(B) shows loop 4 according to the first embodiment. In the comparative example shown in FIG. 6(A), the rows of warp threads 107 are arranged at substantially equal intervals. Therefore, loop 104 is inclined at approximately 45° with respect to the thickness direction when viewed from the warp direction. In the first embodiment shown in FIG. 6(B), the rows of a pair of warp threads 7 that form loop 4 and are adjacent to each other are paired. That is, each row of warp threads 7 approaches the row of warp threads 7 that is connected by loop 4 and adjacent thereto, and is arranged farther away from the row of warp threads 7 adjacent to the opposite side. Therefore, the inclination of loop 4 with respect to the thickness direction when viewed from the warp direction becomes smaller than 45°. For this reason, the papermaking seam felt 1 (see FIG. 1) according to the first embodiment can easily engage and join the loops 4 provided at both ends thereof with each other.

[0041] The materials constituting the warp 7, the upper weft 8, and the lower weft 9 are not particularly limited, but polyamide resins and polyester resins are preferred. Among the polyamide resins, aliphatic polyamide resins are preferred, and more preferably nylon. Examples of nylon include 66 nylon, 6 nylon, 12 nylon, 11 nylon, 610 nylon, 612 nylon, etc. These may be used alone or in combination of two or more. The polyester resin is not particularly limited as long as it is a polyester composed of a dicarboxylic acid and a glycol, and may be polyethylene terephthalate (PET), polypropylene terephthalate, polybutylene terephthalate (PBT), polyethylene naphthalate, etc. These may be used alone or in combination of two or more. Also, the warp 7, the upper weft 8, and the lower weft 9 may be composed of the same material as each other or different materials. Further, each yarn may be composed of a single material or may be composed of two or more materials having different materials. Furthermore, each yarn may contain an inorganic filler and / or an organic filler. The types of the warp 7, the upper weft 8, and the lower weft 9 are not particularly limited, and for example, they may be monofilament single yarns, monofilament twisted yarns, multifilament twisted yarns, or combinations thereof. The diameter of the warp 7 is preferably 0.29 mm to 0.39 mm, and the diameter of the weft 6 is preferably 0.29 mm to 0.42 mm. For example, every other one of the warp 7, a part of the upper weft 8, and / or a part of the lower weft 9 may use a fluorescent yarn or a colored yarn. By using a fluorescent yarn or a colored yarn, it becomes easier to perform the stitching when stitching the loop portion 5.

[0042] Refer to FIGS. 2 to 4. The base fabric 2 is manufactured by an operator performing the following steps. The base fabric 2 is woven with the warp 7 as the warping yarn and the weft 6 as the inserting yarn. The portion that is to become the folded portion 13 in the warp 7 is formed by removing the weft 6 from the end in the warp direction after weaving, or by not inserting the weft 6 into that portion. The tip of the corresponding warp 7 is folded back to form a loop 4, and further, the portion on the tip side of the loop 4 in the folded portion 13 is woven into the ground portion 10 up to the joint 14. After the joint 14 is formed, the portion on the tip side of the folded portion 13 beyond the joint 14 and the portion on the loop 4 side of the warp 7 that forms the joint 14 with the folded portion 13 are cut. The cut end is preferably arranged on the running surface side.

[0043] Referring to FIGS. 1 to 6, the function and effect of the base fabric 2 will be described.

[0044] Since the warp 7 forms a structure with a larger crimp in the end ground portion 11 than in the main ground portion 12, the resistance to the warp 7 coming out in the end ground portion 11 increases. Therefore, even if a force is applied to the warp 7 in the direction of pulling it out from the loop 4, the warp 7 coming out is suppressed.

[0045] The tip side end of the folded portion 13 and the ends of the other warps 7 overlap each other by the number of 5 to 13 wefts 6 to form the joint 14. Therefore, a frictional force acts between the warps 7 that overlap each other, and the warps 7 coming out from the weft 6 at the portion where the joint 14 is formed are suppressed.

[0046] Since the main ground portion 12 is composed of a structure with a smaller crimp than the end ground portion 11, the paper surface property is better than that of the end ground portion 11. By providing the main ground portion 12 having a structure with a relatively small crimp, the paper surface property becomes better compared to the case where the entire ground portion 10 has a structure with a large crimp. Also, by setting the length in the warp direction of the end ground portion 11 to 5 to 7 cm, the balance between the paper surface property and the suppression of the loop 4 coming out is improved.

[0047] By arranging 13.8 to 17.7 weft yarns 6 per 1 cm in the warp direction, the balance of water squeezing property, paper surface property and durability is improved.

[0048] Since the weaving pattern of each row of warp yarns 7 itself is not mirror-symmetric with respect to the cross-section orthogonal to the warp direction, the force applied from the warp yarns 7 to the weft yarns 6 is biased. However, between the rows of warp yarns 7 of warp No. 1 to 4 and the rows of warp yarns 7 of warp No. 5 to 8, since the weaving patterns of the warp yarns 7 are mirror-symmetric with respect to the cross-section orthogonal to the warp direction, forces are applied to the weft yarn 6 in opposite directions to each other. For this reason, the positions of the upper weft yarn 8 and the lower weft yarn 9 are stabilized at positions shifted from each other in the warp direction.

[0049] The ratio of the number of upper weft yarns 8 to the number of lower weft yarns 9 is 1:1, and by arranging the upper weft yarn 8 and the lower weft yarn 9 alternately at positions shifted from each other in the warp direction, compared with the case where the upper weft yarn 8 and the lower weft yarn 9 are aligned in the thickness direction, the compressibility in the thickness direction is reduced. For this reason, the stretchability in the warp direction is reduced and the dimensional stability is excellent.

[0050] In the vicinity of each end in the warp direction, by arranging the joint 14 at a distance of 250 or more weft yarns 6 from the loop portion 5, the folded portion 13 is woven into the weft yarn 6 with a length of a predetermined value or more, and the effect of suppressing the slipping of the warp yarn 7 is enhanced.

[0051] In the vicinity of each end in the warp direction, the joints 14 adjacent to each other in the weft direction are arranged at a distance of 17 or more weft yarns 6 from each other in the warp direction, so that the positions of the joints 14 where the warp yarns 7 are densely arranged are dispersed, and the deterioration of the paper surface property and water squeezing property due to the joints 14 is suppressed.

[0052] Fig. 7(A) shows the ground portion 10 according to a modification of the first embodiment. As shown in Figs. 7(B) and 7(C), the edge ground portion 11 and the main ground portion 12 of the base fabric 2 in the main example of the first embodiment described above are constituted by a structure in which the duality of the weft yarns 6 is lost, that is, a structure in which the upper weft yarn 8 and the lower weft yarn 9 are displaced from each other in the warp direction. The ground portion 10 of the base fabric 2 according to the modification is constituted by a structure in which the duality of the weft yarns 6 is maintained, that is, a structure in which the upper weft yarn 8 and the lower weft yarn 9 are arranged in alignment with each other in the thickness direction. In the example shown in Fig. 7(A), the warp yarn 7 is woven into the weft yarn 6 so as to repeatedly pass above the upper weft yarn 8, between the upper weft yarn 8 and the lower weft yarn 9, below the lower weft yarn 9, and between the upper weft yarn 8 and the lower weft yarn 9. As another weaving pattern, although not shown, the warp yarn 7 repeatedly passes above the upper weft yarn 8, below the lower weft yarn 9, and between the upper weft yarn 8 and the lower weft yarn 9, and the structure of this weaving pattern has a larger crimp than the structure shown in Fig. 7(A). Further, as another weaving pattern, although not shown, the warp yarn 7 repeatedly passes above the upper weft yarn 8, between the upper weft yarn 8 and the lower weft yarn 9, between the upper weft yarn 8 and the lower weft yarn 9, below the lower weft yarn 9, between the upper weft yarn 8 and the lower weft yarn 9, and between the upper weft yarn 8 and the lower weft yarn 9, and the structure of this weaving pattern has a smaller crimp than the structure shown in Fig. 7(A). The base fabric 2 according to the modification uses such a structure in which the duality of the weft yarns 6 is maintained, and the warp yarn 7 in the edge ground portion 11 forms a structure with a larger crimp than the warp yarn 7 in the main ground portion 12.

[0053] Next, with reference to Figs. 8 to 10, a second embodiment according to the present invention will be described. In the description, the configurations common to and similar to those of the first embodiment will be described only in terms of the differences, and the same reference numerals will be given. The papermaking seam felt base fabric 21 (hereinafter referred to as "base fabric 21") according to the second embodiment is different from the first embodiment in that the ground portion 22 is constituted by a single structure except for the portion where the folded portion 23 is woven in.

[0054] The base fabric 21 includes a weft yarn 6 containing a plurality of upper weft yarns 8 and lower weft yarns 9 extending in the weft direction, and a plurality of warp yarns 7 extending in the warp direction and into which the weft yarn 6 is woven. The weft yarn rows of weft yarn Nos. 1, 3, 5, 7 are constituted by the upper weft yarns 8, and the weft yarn rows of weft yarn Nos. 2, 4, 6, 8 are constituted by the lower weft yarns 9.

[0055] The base fabric 21 includes loop portions 5 provided at both end portions in the warp direction, and a ground portion 22 disposed between the two loop portions 5 and into which the weft yarn 6 weaves the warp yarns 7.

[0056] In the ground portion 22, except for the folded-back portion 23, the warp yarns 7 are woven into the weft yarn 6 in the same manner as the main ground portion 12 (see FIG. 2) of the first embodiment. The folded-back portion 13 is woven into the weft yarn 6 in a weaving pattern similar to the end ground portion 11 of the first embodiment, except for the loop 4 and the seam 14. The other portions of the warp yarns 7 in the ground portion 22 are woven into the weft yarn 6 in the same weaving pattern as the main ground portion 12 of the first embodiment. The folded-back portion 23 constitutes a part of the warp yarn rows of warp yarn Nos. 1, 3, 5, 7.

[0057] In the ground portion 22, the portion of the folded-back portion 23 excluding the seam 14 is woven into the weft yarn 6 so as to repeat passing above the upper weft yarn 8, above the lower weft yarn 9, below the upper weft yarn 8, below the lower weft yarn 9, below the upper weft yarn 8, and above the lower weft yarn 9. The folded-back portion 23 of the warp yarn row of warp yarn No. 3 is woven into the weft yarn 6 shifted by two weft yarns 6 toward the smaller weft yarn No. with respect to the folded-back portion 23 of the warp yarn row of warp yarn No. 1. The folded-back portion 23 of the warp yarn row of warp yarn No. 5 is woven into the weft yarn 6 shifted by two weft yarns 6 toward the larger weft yarn No. with respect to the folded-back portion 23 of the warp yarn row of warp yarn No. 1. The folded-back portion 23 of the warp yarn row of warp yarn No. 7 is woven into the weft yarn 6 in the same manner as the folded-back portion 23 of the warp yarn row of warp yarn No. 1.

[0058] Focusing on a pair of warp threads 7 arranged to form two warp thread rows connected by loop 4, one of the pair of warp threads 7 (warp threads No. 8, 2, 4, 6) is folded back to form loop 4, and the portion on the tip side of loop 4 in the folded-back portion 23 is woven into the ground portion 22. The tip-side end of this folded-back portion 23 and the ends of the other of the pair of warp threads 7 (warp threads No. 1, 3, 5, 7) are arranged to overlap when viewed in the weft direction in the ground portion 22 (woven into the weft thread 6 of a common weft thread No.), and a joint 14 (the portion surrounded by a broken line in the figure) is formed. The length and arrangement of joint 14 are the same as those in the first embodiment. The way of weaving the warp threads 7 in joint 14 follows the weaving pattern of the warp threads 7 on the center side in the warp direction from joint 14.

[0059] In the ground portion 22, the folded-back portion 23 excluding the joint 14 forms a structure with a larger crimp than other portions (the joint 14, the portions on the center side in the warp direction of the warp threads No. 1, 3, 5, 7 from the joint 14, and the warp threads No. 8, 2, 4, 6). For this reason, the resistance to slipping out of the folded-back portion 23 increases. For this reason, even when a force is applied to the warp threads 7 in the direction of pulling out from loop 4, the slipping out of the warp threads 7 is suppressed. When a tensile force is applied to loop 4, the portion that is likely to slip out from the ground portion 22 is the folded-back portion 23. For this reason, in a pair of adjacent warp threads 7 that form loop 4, even if the crimp of the warp thread 7 on the side opposite to the folded-back portion 23 is small, the influence on the effect of suppressing the slipping out of the warp thread 7 is small. Also, near the end of the base fabric 21, since the crimp of the warp thread 7 on the side opposite to the folded-back portion 23 in the pair of warp threads 7 is small, the paper surface property is improved.

Example

[0060] Regarding Example 1 corresponding to the first embodiment, Example 2 corresponding to the second embodiment, and a comparative example (the arrangement of the joint is the same as in Example 1) woven in a weaving method in which the entire ground portion including the folded-back portion corresponds to the main ground portion 12 of the first embodiment, samples were set on a strograph under the following test conditions, and a strength test of the base fabric including the loop portion was performed by a tensile test. <Test Conditions> Sample dimensions: length 75 cm × width 3 cm Test length: 65 cm (set on the strograph with the core wire part as the center) Test width: width 2.5 cm (align with the number of warp threads for 2.5 cm) Test speed: 200 mm / min

[0061] The test results were as follows. In Examples 1 and 2, about 1.25 to 1.35 times the force was required because the warp threads slipped out compared to the comparative example. <Result> Example 1: 35.6 kg / cm Example 2: 38.2 kg / cm Comparative example: 28.4 kg / cm

[0062] With the above, the description of the specific embodiments ends. However, the present invention is not limited to the above embodiments or modified examples, and can be widely modified and implemented. The seam felt for papermaking may be used in papermaking machines other than paper machines, for example, pulp machines. The weaving method of the warp and weft threads may be changed within the range that satisfies the conditions regarding the size of the crimp described above. In the ground part of the second embodiment, instead of the entire folded part excluding the joint, a part of it may form a structure with a larger crimp than other parts. The joint may be configured such that the tips of two warp threads abut each other instead of being formed by overlapping two warp threads.

Explanation of reference numerals

[0063] 2, 21: Base fabric of seam felt for papermaking 4: Loop 5: Loop part 6: Weft thread 7: Warp thread 8: Upper weft thread 9: Lower weft thread 10, 22: Ground part 11: End ground part 12: Main ground part 13, 23: Folded part 14: Joint

Claims

1. A papermaking seam felt base fabric comprising a weft yarn extending in the weft direction and a lower weft yarn disposed on the running surface side of the upper weft yarn and extending in the weft direction, and a warp yarn extending in the warp direction into which the weft yarn is woven, The weft yarn includes a ground portion into which the warp yarn is woven and a loop portion protruding from both ends of the ground portion in the warp direction, The loop portion includes a plurality of loops formed by folding back the warp yarn, In a pair of the warp yarns arranged to form two warp yarn rows connected by the loops near the end portion in the warp direction, one of the pair of warp yarns is folded back to form the loop, and the tip-side end portion of the folded-back portion of the one and the other end portion of the pair of warp yarns are arranged so as to overlap or abut each other when viewed in the weft direction in the ground portion, thereby forming a joint, A papermaking seam felt base fabric, wherein in a pair of the warp yarns, at least a part of the folded-back portion of the one forms a structure with a larger crimp than a portion disposed at the center in the warp direction relative to the joint.

2. The ground portion includes an end ground portion disposed adjacent to each of the loop portions and a main ground portion disposed between the two end ground portions, The joint is formed in the main ground portion, The warp yarns in the end ground portion form a structure with a larger crimp than the warp yarns in the main ground portion. The papermaking seam felt base fabric according to claim 1.

3. The length between the weft yarns disposed at both ends in the warp direction in the end ground portion is 5 to 7 cm. The papermaking seam felt base fabric according to claim 2.

4. In the ground portion, the portion excluding the joint in the folded-back portion forms a structure with a larger crimp than other portions in the pair of warp yarns. The papermaking seam felt base fabric according to claim 1.

5. The weft yarns are arranged at 13.8 to 17.7 per 1 cm in the warp direction. The papermaking seam felt base fabric according to any one of claims 1 to 4.

6. The joint is formed by the end portion of the folded-back portion of the one and the other end portion overlapping each other by 5 to 13 weft yarns when viewed in the weft direction. The seam felt base fabric according to any one of claims 1 to 5.

7. In the vicinity of each end portion in the warp direction, the seam is arranged at a distance of 250 or more of the weft yarns away from the loop portion, the seam felt base fabric according to any one of claims 1 to 6.

8. In the vicinity of each end portion in the warp direction, the seams adjacent to each other in the weft direction are arranged such that the closest portions of each other are separated from each other by a distance of 17 or more of the weft yarns in the warp direction, the seam felt base fabric according to any one of claims 1 to 7.

9. The ratio of the number of the upper weft yarns to the number of the lower weft yarns is 1:1, The upper weft yarns and the lower weft yarns are alternately arranged at positions shifted from each other in the warp direction, the seam felt base fabric according to any one of claims 1 to 8.

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