JP2020158925A - Seam felt for papermaking and method for producing the same - Google Patents

Abstract

To improve the surface properties of papermaking seam felt with two base fabrics stacked on top of each other and to suppress vibration.SOLUTION: A seam felt 1 for papermaking of this invention includes a base cloth 2 and a butt fiber layer 3. The base cloth 2 includes a lower base cloth 10 and an upper base cloth 20 superposed on the lower base cloth 10. Both ends of the lower base cloth 10 are joined to each other, but both ends of the upper base cloth 20 are close to each other without being joined to each other. Since the front upper base cloth loop 24 of the upper base cloth 20 covers a seam part of the lower base cloth 10 like a flap, the level difference between the seam part of the lower base cloth 10 and the front and rear parts thereof is relaxed. Therefore, the seam mark is suppressed, and the vibration when the seam part passes through the roll of the paper machine is suppressed.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a papermaking seam felt comprising two base fabrics stacked on top of each other and a butt fiber layer integrated into the base fabric.

A press part that mechanically squeezes water from wet paper in a paper machine, and the felt for papermaking used for transporting and squeezing wet paper consists of a base cloth in which warp and weft are woven together and short fibers. The butt fiber layer is integrally formed by needling. Felt for papermaking has wet paper transportability, water squeezing, surface property that does not mark the surface of paper (paper surface property), initial familiarity with respect to the time from mounting on a paper machine to a preferable state, and antifouling. Properties, durability, etc. are required. The seam felt for papermaking is provided with loops at both ends in the length direction, and the loops at both ends are joined to each other to form an endless shape and attached to a paper machine.

When the seam felt for papermaking is used in a portion where the amount of dehydration from wet paper is large, such as a press part such as white board papermaking or pulp papermaking or a shoe press part, it is preferable that the void volume is large. In order to increase the void volume, a base cloth having a laminated structure in which two base cloths are superposed on each other may be used. In a papermaking seam felt provided with such two base fabrics, when both ends of each base fabric are joined, the seam portion becomes two steps and becomes thicker, so that there is a step between the seam portion and the other portion. growing. Therefore, there is a problem that the seam mark attached to the surface of the paper becomes deep and the surface property deteriorates, and the vibration becomes large when the seam portion passes on the roll on which the seam felt for papermaking runs. Therefore, for example, in the invention described in Patent Document 1, in a seam felt for papermaking provided with a base cloth having a laminated structure, the seam mark is suppressed by shifting the positions of the loops of the base cloth overlapped with each other back and forth. ing.

Japanese Unexamined Patent Publication No. 11-323763

In the seam felt for papermaking described in Patent Document 1, since the positions of the seams of the upper and lower base fabrics are displaced, the increase in the thickness of the seams is suppressed, and the seam marks and vibrations are suppressed. There has been a demand for improved surface properties and suppression of vibration.

It is also required to facilitate the joining of seams. For example, it was considered to facilitate the joining by not joining one of the two base cloths, but in this case, the tip of the loop of the unjoined base cloth is cracked (cut), and the loop is formed. There was a problem that the inserted filling thread and the weft thread near the loop were unraveled and came out. When the filling thread was thickened to prevent the loop from being crushed in order to prevent the loop from cracking, the loop part became thicker than the ground part, causing seam marks and vibration.

In view of such a problem, an object of the present invention is to improve the surface property of a papermaking seam felt having two base fabrics superposed on each other and to suppress vibration.

At least some embodiments of the present invention are a papermaking seam felt (1) comprising a base fabric (2) and a butt fiber layer (3) integrated with the base fabric, wherein the base fabric is , The lower base cloth (10), and the upper base cloth (20) arranged on the upper side of the lower base cloth, and the lower base cloth includes the lower base cloth warp (11) and the lower base cloth weft. The lower base fabric portion (13) formed by weaving (12) to each other, and the front lower base fabric formed by folding back the lower base fabric warp threads protruding from one end in the mechanical direction of the lower base fabric portion. The loop (14) is formed by projecting from the other end of the lower base fabric portion in the machine direction and the lower base fabric warp is folded back, and is joined to the front lower base fabric loop by a core wire to form the front side. The upper base cloth includes a rear lower base cloth loop (15) located on the rear side in the mechanical direction with respect to the lower base cloth loop, and the upper base cloth includes an upper base cloth warp (21) and an upper base cloth weft (22). An upper base fabric portion (23) formed by weaving each other, and a front upper base fabric loop (23) formed by folding back the upper base fabric warp threads protruding from one end in the machine direction in the upper base fabric portion. 24) and the upper base fabric portion, which protrudes from the other end in the mechanical direction and is formed by folding back the upper base fabric warp, and is close to the front upper base fabric loop without being joined to the front side upper. A rear upper base cloth loop (25) located on the rear side in the mechanical direction with respect to the base cloth loop is included, and the tip of the rear upper base cloth loop is located behind the core wire and is located on the front side. The positions of the tip of the upper base cloth loop and the tip of the front lower base cloth loop in the mechanical direction are substantially equal to each other. Here, "the positions of the tip of the front upper base cloth loop and the tip of the front lower base cloth loop in the mechanical direction are substantially equal to each other" means that the difference between the two mechanical positions is the thickness of the upper base cloth warp. This includes cases where the total thickness of the warp and lower base cloth warp is less than or equal to the total value.

According to this configuration, the front upper base cloth loop, which is not joined to the rear upper base cloth loop, covers most or the whole of the seam part of the lower base cloth like a flap, so that the seam part of the lower base cloth and the seam part are covered. The step between the front and rear parts is relaxed. Therefore, the seam mark is suppressed, the paper surface property is improved, and the vibration when the seam portion passes through the roll is also suppressed.

In at least some embodiments of the present invention, in the above configuration, the inner diameter of at least one of the front upper base cloth loop and the rear upper base cloth loop in the thickness direction corresponds to the front lower base cloth loop or the said front side lower base cloth loop. It is characterized in that it is smaller than the inner diameter of the posterior lower base cloth loop in the thickness direction. Here, the "inner diameter in the thickness direction" of the loop means the length between the inner edges of the most bulging portion in the thickness direction of the loop.

According to this configuration, the step in the thickness direction between the upper base fabric portion and the front upper base cloth loop and / or the rear upper base cloth loop is reduced, and seam marks and vibrations are suppressed.

In at least some embodiments of the present invention, in any of the above configurations, at least one of the anterior upper base cloth loop and the posterior upper base cloth loop is relative to the thickness direction when viewed from the mechanical direction. It is characterized by being tilted by 15 ° to 65 °.

According to this configuration, the front and / or rear upper base fabric loops are inclined toward the machine crossing direction, so that there is a step between the upper base fabric portion and the front and / or rear upper base fabric loops. It is suppressed. Therefore, seam marks and vibrations are suppressed. Further, since the front side and / or the rear side upper base cloth loop is inclined, the tip of the front side and / or the rear side upper base cloth loop is less likely to be cracked even when pressure is applied during use.

In at least some embodiments of the present invention, in any of the above configurations, the upper base fabric weft is a central upper base fabric weft (22a) arranged at the center of the upper base fabric portion in the mechanical direction. , 2 to 8 end upper base fabric wefts (22b) arranged at both ends of the upper base fabric portion in the machine direction, and the end upper base fabric weft is the central upper base. It is characterized by being easier to bend than cloth weft.

According to this configuration, the upper base fabric weft at the end is more easily bent than the upper base fabric weft at the center, so that the cushioning property of the front and rear upper base fabric loops is increased, and seam marks and vibrations are suppressed.

At least some embodiments of the present invention are methods of producing any of the above-described papermaking seam felts, the step of weaving the lower base fabric and the upper base fabric, and the front lower base fabric loop. The lower base cloth and the upper base cloth are overlapped with each other to form the base cloth so that the lower base cloth and the upper base cloth loop overlap each other in the vertical direction, and the lower base cloth portion and the upper base cloth portion are formed. A step of fixing the vicinity portions of the front lower base cloth loop and the front upper base cloth loop to each other, and a lower base cloth temporary core wire (25) to the front lower base cloth loop and the rear lower base cloth loop to join each other. And the step of inserting the upper base cloth temporary core wire (26) into the front side upper base cloth loop and the rear side upper base cloth loop in order to join each other, and the step of needling short fibers to the base cloth. A step of forming the butt fiber layer, and a step of heating and drying the base cloth and the bat fiber layer with the base cloth under tension in the mechanical direction after removing the temporary core wire of the upper base cloth. The lower base fabric temporary core wire is removed, and the butt fiber layer is separated along the adjacent portions of the front and rear lower base fabric loops and the overlapping portions of the front and rear upper base fabric loops. It is characterized by including a step of making it into an end shape.

According to this configuration, the front side of the lower and upper base fabrics are fixed to each other, and the heat treatment is performed in a state where tension is applied in the mechanical direction, so that the front upper base fabric loop is formed with the seam part of the lower base fabric and the seam part of the lower base fabric. It is placed in a preferred position with respect to the rear upper base fabric loop. That is, the front upper base cloth loop is arranged at a position that covers the seam portion of the lower base cloth from above, and is slightly separated from the position where the tip slightly overlaps the rear upper base cloth loop in the lateral view. It is placed between the positions to be used.

In at least some embodiments of the present invention, in the configuration of the above method, the weaving step is folded back at the weaving core wire (6) by using the upper base fabric weft as a warping yarn and the upper base fabric warp as a driving yarn. As described above, the total thickness of the upper base cloth temporary core wire inserted into the front side upper base cloth loop and the rear side upper base cloth loop includes weaving the upper base cloth warp yarn into the upper base cloth weft. It is characterized in that it is thinner than the entire thickness of the weaving core wire inserted through the front upper base cloth loop and the rear upper base cloth loop. Here, the total thickness of the core wire (temporary core wire for upper base cloth or core wire for weaving) is the thickness of one thread when the core wire is composed of one thread, and the core wire is a plurality of threads. When it is composed of threads, it is the thickness when the core wire is regarded as one thread in which the plurality of threads are bundled.

According to this configuration, since the upper base cloth temporary core wire is thinner than the weaving core wire, the front side and rear side upper base cloth loops are smaller than those at the time of weaving in the post-process.

In at least some embodiments of the present invention, in any of the configurations of the above methods, the proximity portions fixed to each other are the lower base fabric portion and the front lower base fabric loop and the front side in the upper base fabric portion. It is characterized in that the sewing machine is sewn within a range of 1 cm to 20 cm in the mechanical direction from the boundary with the upper base cloth loop.

According to this configuration, the anterior upper base fabric loop is placed in a preferred position with respect to the seam portion of the lower base fabric and the rear upper base fabric loop in the finished product.

At least some embodiments of the present invention are characterized by further comprising, in any of the configurations of the above methods, a step of subjecting the base fabric on which the butt fiber layer is formed to a heat pressurization treatment in the thickness direction. To do.

According to this configuration, the front and rear upper base fabric loops are flattened, and seam marks and vibrations are further suppressed.

According to the present invention, it is possible to improve the surface property of a papermaking seam felt having two base fabrics overlapped with each other and suppress vibration.

Cross-sectional view orthogonal to the weft around the seam portion of the papermaking seam felt according to the embodiment. Photograph of the upper base cloth loop of the seam felt for papermaking according to the embodiment (A: Photograph seen from the machine direction, B: Photograph seen from the machine orthogonal direction) Explanatory drawing which shows the manufacturing method of the base cloth of the seam felt for papermaking which concerns on embodiment. Explanatory drawing which shows the manufacturing method of the seam felt for papermaking which concerns on embodiment Photograph of a cross section orthogonal to the weft around the seam portion of the papermaking seam felt according to Examples and Comparative Examples. Photograph showing the result of pressure distribution measurement around the seam part of the seam felt for papermaking according to Examples and Comparative Examples.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of the periphery of the seam portion in the papermaking seam felt (hereinafter referred to as “felt”) 1 according to the embodiment.

The felt 1 includes a base cloth 2 and a butt fiber layer 3 formed by needling a short fiber sheet so as to be integrated with the base cloth 2, and is endless in the machine direction (length direction). It is joined and attached to a paper machine. The machine direction (MD direction) is the direction in which the felt 1 travels when attached to the paper machine, and the machine orthogonal direction (CD direction) is the direction along the surface of the felt 1 orthogonal to the machine direction. The warp and weft generally extend along the machine direction and the machine orthogonal direction, respectively. The base cloth 2 has a laminated structure including a lower base cloth 10 arranged on the running surface side and an upper base cloth 20 arranged on the papermaking surface side so as to overlap the lower base cloth 10 on the upper side. .. The running surface side is referred to as the lower side, and the papermaking surface side is referred to as the upper side. Felt 1 is used, for example, in the press part of pulp papermaking.

The lower base fabric 10 protrudes from one end of the lower base fabric portion 13 formed by weaving two layers of lower base fabric warp yarns 11 and one layer of lower base fabric weft yarns 12 in the same number of upper and lower layers, and one end of the lower base fabric portion 13. A plurality of front lower base fabric loops 14 and a plurality of rear lower base fabric loops 15 projecting from the other end of the lower base fabric portion 13 in the mechanical direction are included. The lower base cloth 10 is formed by engaging the front lower base cloth loop 14 and the rear lower base cloth loop 15 with each other and inserting the core wire 4 into the front lower base cloth loop 14 and the rear lower base cloth loop 15. It becomes endless. The side on which felt 1 travels in the mechanical direction is referred to as the front side, and the opposite side in the mechanical direction is referred to as the posterior side. In the state of being joined to each other, the front end side of the front lower base cloth loop 14 and the rear lower base cloth loop 15 overlap each other in a side view (when viewed from the machine orthogonal direction), and the posterior lower base cloth loop 15 is the front lower base cloth loop 15. It is located behind the cloth loop 14. The front lower base cloth loop 14 and the rear lower base cloth loop 15 are each formed by folding back the lower base cloth warp yarn 11 protruding from the end portion of the lower base cloth portion 13 in the mechanical direction. The front lower base cloth loop 14 and the rear lower base cloth loop 15 are substantially parallel to the thickness direction of the felt 1 when viewed from the mechanical direction.

The upper base fabric 20 protrudes from one end of the upper base fabric portion 23 formed by weaving two layers of upper base fabric warp yarns 21 and one layer of upper base fabric weft yarns 22 in the same number of upper and lower layers and one end of the upper base fabric portion 23. A plurality of front upper base cloth loops 24 and a plurality of rear upper base cloth loops 25 projecting from the other end of the upper base fabric portion 23 in the mechanical direction are included. The front upper base cloth loop 24 and the rear upper base cloth loop 25 are close to each other without being joined to each other. From the side view, the front upper base cloth loop 24 and the rear upper base cloth loop 25 are in a state where their tips are slightly overlapped with each other, their tips are aligned with each other, or their tips are slightly separated from each other in the mechanical direction. The rear upper base cloth loop 25 is located on the rear side of the front side upper base cloth loop 24. The front upper base cloth loop 24 and the rear upper base cloth loop 25 are each formed by folding back the upper base cloth warp yarn 21 protruding from the end portion of the upper base cloth portion 23 in the mechanical direction.

In the mechanical direction, the position of the tip of the anterior upper base cloth loop 24 coincides with the position of the tip of the front lower base cloth loop 14 or is slightly offset back and forth, preferably aligned or slightly rearward. It is out of alignment. The deviation of the mechanical position between the tip of the front upper base cloth loop 24 and the tip of the front lower base cloth loop 14 is preferably the total value of the thickness of the upper base cloth warp 21 and the thickness of the lower base cloth warp 11. It is less than or equal to the degree, more preferably 0.75 times or less of the total value, and further preferably 0.5 times or less of the total value. Therefore, the tip of the front upper base cloth loop 24 is located at least behind the core wire 4, and preferably the front side upper base cloth loop 24 is inserted through the core wire 4 to form the front side lower base cloth loop 14 and the rear side lower base cloth loop. The entire seam portion joined to each other by 15 is covered from above, and the front upper base cloth loop 24 moves like a flap to protect the seam portion. The rear upper base cloth loop 25 covers the base end side of the rear side lower base cloth loop 15 and the end portion of the lower base cloth portion 13 adjacent thereto from the upper side. Further, the tip of the tip of the rear upper base cloth loop 25 is close to the tip of the front upper base cloth loop 24 and is located behind the core wire 4.

The inner diameter of the front upper base cloth loop 24 in the thickness direction is smaller than the inner diameter of the front lower base cloth loop 14 in the thickness direction, and the inner diameter of the rear upper base cloth loop 25 in the thickness direction is the rear lower base cloth. It is smaller than the inner diameter of the loop 15 in the thickness direction. For example, the inner diameters of the front and rear upper base cloth loops 24 and 25 in the thickness direction are 0.3 to 0.9 mm, and the inner diameters of the front and rear lower base cloth loops 14 and 15 in the thickness direction are 0.8 to 0.9 mm. It is preferably 1.8 mm, and the inner diameters of the front and rear upper base cloth loops 24 and 25 in the thickness direction are less than half of the inner diameters of the front and rear lower base cloth loops 14 and 15 in the thickness direction. Is preferable. Only one of the front lower base cloth loop 14 and the front upper base cloth loop 24 and the rear lower base cloth loop 15 and the rear upper base cloth loop 25 has an inner diameter of the upper side smaller than that of the lower side. The relationship may be established.

In addition, the front and rear upper base cloth loops 24 and 25 have a slight degree of freedom with respect to the movement of rotation about the machine direction, so that they approach parallel to the machine orthogonal direction during press working or product use. Tilt. The angle is 15 ° to 65 ° with respect to the thickness direction when viewed from the machine direction. If it is less than 15 ° (smaller), the inclination is too small to obtain the effect of approaching smoothness, and the step between the upper base fabric portion 23 and the front side and / or the rear side upper base fabric loops 24 and 25 is suppressed. However, seam marks and vibrations may occur. Further, when pressure is applied during use, cracks may occur at the tips of the front side and / or the rear side upper base cloth loops 24 and 25. Further, an inclination larger than 65 ° is difficult to realize due to the structure of the base cloth 2, and it becomes difficult to insert the filling thread 5. The upper and lower warp threads 11 and 21 forming one front or rear upper base cloth loops 24 and 25 are woven together at the bases 13 and 23 and do not shift. However, as shown in FIGS. 1 and 2, in the vicinity of the anterior and posterior upper base fabric loops 24 and 25, the upper and lower upper base fabric warp threads 21 form different weave structures and are divided into two layers. In this state, when pressure is applied, the surfaces formed by the front and rear upper base fabric loops 24 and 25 tend to tilt in the machine orthogonal direction. In addition, only one of the front side upper base cloth loops 24 and 25 may be tilted.

The upper base fabric weft 22 is a central upper base fabric weft 22a arranged at the center of the upper base fabric portion 23 in the machine direction, and an end portion arranged at both ends of the upper base fabric portion 23 in the machine direction. Includes base fabric weft 22b. The end upper base cloth weft 22b is a thread that is more easily bent (flatted) than the central upper base cloth weft 22a. For example, the central upper base cloth weft 22a is a monofilament, and the end upper base cloth weft 22b has a thickness equivalent to that of the central upper base cloth weft 22a, and is a multifilament, a multifilament twisted yarn, or a monofilament twisted yarn. Is. Since the end upper base cloth weft 22b is more easily bent than the central upper base cloth weft 22a, the cushioning property of the front side upper base cloth loops 24 and 25 is improved. There are 2 to 8 base fabric wefts 22b on the ends at each of both ends.

The filling thread 5 may be inserted into the front upper base cloth loop 24 in one row and the rear upper base cloth loop 25 in one row, respectively. The filling yarn 5 is, for example, a multifilament, a multifilament twisted yarn, a monofilament twisted yarn or a spun yarn so as not to prevent the front upper base fabric loop 24 and the rear upper base fabric loop 25 from tilting toward the machine orthogonal direction. It is preferable that the material is a thread that is easily bent, and the number of threads is 1 to 4. The core wire 4 is made of, for example, a synthetic resin such as nylon, polyamide, polyester, polyethylene, polypropylene, or polyvinyl chloride, and the number of the core wire 4 is preferably 5 to 10. The filling yarn 5 prevents the fibers of the butt fiber layer 3 from coming off and the front and rear upper base fabric loops 24 and 25 from being overly crushed when pressed.

As a material for the lower base cloth warp 11, the lower base cloth weft 12, the upper base cloth warp 21, and the upper base cloth weft 22, for example, synthetic resins such as nylon, polyamide, polyester, polyethylene, polypropylene, and polyvinyl chloride can be used.

A method for producing felt 1 will be described with reference to FIGS. 1, 3 and 4. In FIG. 4, the lower base cloth weft 12 and the upper base cloth weft 22 are not shown.

First, the lower base cloth 10 and the upper base cloth 20 are woven. For example, as shown in FIG. 3, the lower base cloth weft and the upper base cloth weft 22 are used as warping threads, the lower base cloth warp 11 and the upper base cloth warp 21 are used as driving threads, and the driving threads are folded back at the weaving core wire 6. As described above, the lower base cloth 10 and the upper base cloth 20 may be woven by bag weaving.

Next, as shown in FIG. 4A, the lower base cloth 10 and the upper base cloth 20 are overlapped with each other so that the front lower base cloth loop 14 and the front upper base cloth loop 24 overlap each other. Further, the lower base fabric portion 13 and the upper base fabric portion 23 are prevented from being displaced from each other in the front-rear direction (mechanical direction) between the front side lower base cloth loop 14 and the front side upper base cloth loop 24 by the subsequent step. The portions in the vicinity of the front lower base cloth loop 14 and the front upper base cloth loop 24 are fixed to each other. Here, it is preferable that the position of the tip of the front upper base cloth loop 24 coincides with the position of the tip of the front lower base cloth loop 14 or slightly protrudes in the front-rear direction. Further, the portions of the lower base fabric portion 13 and the upper base fabric portion 23 that are fixed to each other shall be within a range of 1 cm to 20 cm in the mechanical direction from the boundary between the front lower base fabric loop 14 and the front upper base fabric loop 24. Is preferable. The lower base fabric portion 13 and the upper base fabric portion 23 can be fixed to each other, for example, by sewing with a sewing machine (reference numeral 7 in FIG. 4 indicates a sewing thread). By this fixing, the relative position of the front upper base cloth loop 24 with respect to the front lower base cloth loop 14 is maintained.

Next, as shown in FIG. 4B, both ends of the lower base cloth 10 and the upper base cloth 20 are temporarily joined to each other. Specifically, the anterior lower base cloth loop 14 and the rear lower base cloth loop 15 are meshed with each other, and the lower base cloth temporary core wire 16 is inserted into the front side lower base cloth loop 14 and the rear side lower base cloth loop 15. , The front upper base cloth loop 24 and the rear upper base cloth loop 25 are engaged with each other, and the upper base cloth temporary core wire 26 is inserted into the front side upper base cloth loop 24 and the rear side upper base cloth loop 25. The upper base cloth temporary core wire 26 is preferably thinner than the weaving core wire 6 as a whole. Further, the number of the upper base cloth temporary core wires 26 is preferably smaller than the number of the lower base cloth temporary core wires 16.

Next, as shown in FIG. 4B, the filling thread 5 is inserted into the internal spaces of the front upper base cloth loop 24 and the rear upper base cloth loop 25 near the ground.

Next, the short fiber sheet is needling on the base cloth 2 including the lower base cloth 10 and the upper base cloth 20 to form the butt fiber layer 3. By needling the short fibers to the filling thread 5, the effect of preventing the short fibers from falling off by the filling thread 5 is sufficiently exhibited.

Next, as shown in FIG. 4C, after removing the upper base cloth temporary core wire 26, the base cloth 2 and the butt fiber layer 3 are heated and dried in a state where tension is applied in the mechanical direction, and the base cloth 2 is heated and dried. Stabilize the dimensions of. By this process, the posterior upper base cloth loop 25 retracts with respect to the anterior upper base cloth loop 24, and the relative positions of the two are the positions where the tips of the two overlap slightly in the side view, and the tips of the two match. Or the position where the tips of both are slightly separated. Further, the base cloth 2 and the butt fiber layer 3 may be further subjected to a heat pressurization treatment in the thickness direction to flatten the front side and rear side upper base cloth loops 24 and 25.

Next, the lower base cloth temporary core wire 16 is removed, and the butt fiber layer 3 is attached to the front and rear lower base cloth loops 14 and 15 in close proximity to each other, and the front and rear upper base cloth loops 24 and 25 to each other. Cut along the overlapping part to make an end.

After that, the felt 1 is attached to the roll of the paper machine, the front side and the rear side lower base cloth loops 14 and 15 are engaged with each other, and the core wire 4 is inserted into both loops 14 and 15 to join both ends of the felt 1 to each other. The core wire 4 may be the same as or different from the lower base cloth temporary core wire 16. The sewing thread 7 may or may not be removed. Further, a water-soluble thread may be used as the sewing thread 7 so that the sewing thread 7 can be removed by the final process at the time of manufacturing or the use of the product. Further, sewing may be performed in 1 to 4 rows within a range of 1 cm to 20 cm, but 2 to 3 rows are preferable. The number of rows to be carried out can be appropriately selected depending on the combination of the upper and lower base fabrics 10 and 20. If there are too many rows, it will cause deterioration of paper surface, so the minimum number of rows that can fix the upper and lower base fabrics 10 and 20 to each other is preferable. These do not necessarily have to be evenly spaced.

Since the seams of the front and rear lower base fabric loops 14 and 15 are thicker than the lower base fabric portion 13 including the core wire 4, it causes vibration of the seam mark and felt 1 during running. However, since the relatively flat front upper base cloth loop 24 covers the seam portion like a flap, the fluctuation of the step generated in the mechanical direction is alleviated, and the seam mark and vibration are suppressed. In the structure in which the front upper base cloth loop 24 covers the seam portion like a flap, the front upper base cloth loop 24 is less likely to be turned over than the structure in which the rear upper base cloth loop 25 covers the seam portion, and the papermaking surface of the felt 1 is formed. The continuity of the surface on the side is easily maintained.

Since the core wires 4 are not inserted into the front and rear lower base fabric loops 14 and 15, the inner diameter in the thickness direction can be reduced, whereby the upper base fabric portion 23 and the front and rear lower base fabric loops can be reduced. The step in the thickness direction with 14 and 15 becomes small, and seam marks and vibration can be suppressed.

Since the front and rear upper base fabric loops 24 and 25 are inclined toward the machine crossing direction, the difference in thickness between the upper base fabric portion 23 and the front and rear upper base fabric loops 24 and 25 is reduced. Therefore, the step generated in the upper base cloth 20 is suppressed. Therefore, seam marks and vibrations are suppressed. Further, since the front side and rear side upper base cloth loops 24 and 25 are inclined, the tips of the front side and rear side upper base cloth loops 24 and 25 are less likely to be cracked even if pressure is applied during use.

Since the end upper base cloth weft 22b is more easily bent than the central upper base cloth weft 22a, the cushioning properties of the front and rear upper base cloth loops 24 and 25 are increased, and seam marks and vibrations are suppressed.

Since both ends of the upper base cloth 20 are not joined to each other and only both ends of the lower base cloth 10 are joined to each other, the joining becomes easy.

FIG. 5 is a photograph of a cross section orthogonal to the weft around the seam portion of the felt according to the examples and comparative examples of the present invention. 5 (A) to 5 (C) show Comparative Example 1, Example 1 and Example 2, respectively. The felt advances toward the right side of the figure. That is, the front lower base cloth loop and the front upper base cloth loop are on the right side of the figure, and the posterior lower base cloth loop and the front upper base cloth loop are on the left side.

In Comparative Example 1, when the lower base cloth and the upper base cloth are fixed to each other, they are fixed to each other at both the front end portion and the rear end portion of the lower base fabric portion and the upper base fabric portion, and the short fiber sheet is used as the base cloth. This is a felt produced by inserting a filling thread into the front side upper base cloth loop and the rear side upper base cloth loop at the time of needling. In the first embodiment, when the lower base cloth and the upper base cloth are fixed to each other, only the lower base cloth portion and the front end portion of the upper base cloth portion are fixed to each other, and the number of upper base cloth temporary core wires when needling is determined. , Felt manufactured with less than the number of temporary core wires of the lower base cloth. Example 2 is a felt that has been manufactured in the same manner as in Example 1 and then further subjected to heat and pressure treatment in the thickness direction.

In Comparative Example 1, the front and rear upper base fabric loops were largely separated from each other in the mechanical direction. This is due to the displacement of the upper and lower base fabrics that occurs during needling, and the positional relationship between the front and rear upper base fabric loops cannot be maintained only by fixing with sewing machines. When needling, it is necessary to join the upper base cloth loops with temporary core wires so that the distance between the front and rear upper base cloth loops is not too large. In Example 1, after the heat-drying treatment, the posterior upper base cloth loop retracted to a position where the tips of the front side and the rear side upper base cloth loops overlap in a side view. In Example 2, the inner diameters of the front and rear upper base cloth loops in the thickness direction were smaller than those of Example 1, and the front and rear upper base cloth loops were flattened in the side view.

FIG. 6 shows the results of pressure distribution measurement around the seam portion of the felt according to the examples and comparative examples of the present invention. 6 (A) to 6 (D) show Comparative Example 2, Example 1-1, Example 1-2, and Example 2, respectively. The felt advances to the top of the figure.

Comparative Example 2 shown in FIG. 6A is a felt in which both ends of both the lower base cloth and the upper base cloth are joined to each other and the seams of the lower base cloth and the upper base cloth are displaced from each other in the mechanical direction. is there. In Comparative Example 2, since the seam portions overlapped in two steps, the core wire trace of the upper base cloth (the portion extending deeply in the weft direction indicated by the arrow a) clearly appeared. Further, since the short fibers of the butt fiber layer are not easily entangled in the seam portion, a pressure break (a portion extending lightly in the weft direction indicated by the arrow b) is clearly visible.

Example 1-1 shown in FIG. 6B is a felt in which the filling yarn is not inserted into the front and rear upper base fabric loops in the above-mentioned Example 1. In Example 1-1, in addition to having no core wire in the upper base cloth, the front upper base cloth loop covers the seam part of the lower base cloth like a flap to reduce the step between the seam part and the front and rear parts thereof. Therefore, no extreme pressure spots were observed. However, the pressure on the entire felt seam was slightly lower than that on the front and back.

Example 1-2 shown in FIG. 6C is a felt in which the filling yarn is inserted into the front side and rear side upper base cloth loops in the above-mentioned Example 1. In Example 1-2, since the filling yarn was inserted through the front and rear upper base cloth loops, the pressure difference between the entire seam portion of the felt and the front and rear portions thereof was smaller than that in Example 1-1.

Example 2 shown in FIG. 6 (D) corresponds to the above-mentioned Example 2, and is a felt in which a filling yarn is inserted into the front side upper base cloth loop and the rear side upper base cloth loop. In Example 2, as in Example 1-2, no extreme pressure spots were observed, and the pressure difference between the entire seam portion of the felt and the portion before and after the seam portion was smaller than that in Example 1-1.

Although the description of the specific embodiment is completed above, the present invention can be widely modified without being limited to the above embodiment. In the above embodiment, the types and thicknesses of the lower base cloth warp and the upper base cloth warp are the same, and the types and thickness of the lower base cloth weft and the upper base cloth weft are also the same, but they are different from each other. You may be.

1: Paper seam felt 2: Base cloth 3: Bat fiber layer 4: Core wire 5: Filling thread 6: Weaving core wire 7: Sewing thread 10: Lower base cloth 11: Lower base cloth warp thread 12: Lower base cloth weft thread 13: Lower base fabric 14: Front lower base loop 15: Rear lower base loop 16: Lower base temporary core wire 20: Upper base 21: Upper base warp 22: Upper base weft 22a: Central upper base Weft, 22b: End upper base cloth Weft 23: Upper base fabric part 24: Front upper base cloth loop 25: Rear upper base cloth loop 26: Upper base cloth temporary core wire

Claims (8)

A papermaking seam felt including a base cloth and a butt fiber layer integrated with the base cloth.
The base cloth includes a lower base cloth and an upper base cloth arranged on the upper side of the lower base cloth.
The lower base fabric protrudes from the lower base fabric portion formed by weaving the lower base fabric warp and the lower base fabric weft from one end in the mechanical direction of the lower base fabric portion, and the lower base fabric warp is folded back. The front lower base cloth loop formed by the above, and the lower base cloth warp that protrudes from the other end of the lower base fabric portion in the mechanical direction and is folded back to form the front lower base cloth loop by the core wire. Includes a rear lower base fabric loop that is joined and located posterior to the front lower base fabric loop in the mechanical direction.
The upper base fabric projects from the upper base fabric portion formed by weaving the upper base fabric warp and the upper base fabric weft and one end in the mechanical direction of the upper base fabric portion, and the upper base fabric warp is folded back. The front upper base cloth loop formed by the above and the upper base cloth warp protruding from the other end in the mechanical direction of the upper base fabric portion and being folded back to be joined to the front upper base cloth loop. Including a rear upper base cloth loop located on the rear side in the machine direction with respect to the front side upper base cloth loop.
The tip of the posterior upper base cloth loop is located behind the core wire.
A seam felt for papermaking, characterized in that the positions of the tip of the front upper base cloth loop and the tip of the front lower base cloth loop in the machine direction are substantially equal to each other. The inner diameter of at least one of the front upper base cloth loop and the rear upper base cloth loop in the thickness direction is smaller than the inner diameter of the corresponding front side lower base cloth loop or the rear side lower base cloth loop in the thickness direction. The seam felt for papermaking according to claim 1. Claim 1 or 2 characterized in that at least one of the front upper base cloth loop and the rear upper base cloth loop is inclined by 15 ° to 65 ° with respect to the thickness direction when viewed from the machine direction. Seam felt for papermaking described in. The upper base fabric weft is a central upper base fabric weft arranged in the center of the upper base fabric portion in the machine direction and 2 to 8 arranged at both ends of the upper base fabric portion in the machine direction, respectively. Includes base fabric weft on the end of the book
The seam felt for papermaking according to any one of claims 1 to 3, wherein the end upper base cloth weft is more easily bent than the central upper base cloth weft. The method for producing a seam felt for papermaking according to any one of claims 1 to 4.
The step of weaving the lower base cloth and the upper base cloth, and
The lower base cloth and the upper base cloth are overlapped with each other to form the base cloth so that the front lower base cloth loop and the front upper base cloth loop overlap each other in the vertical direction. A step of fixing the front lower base cloth loop and the vicinity portion of the front upper base cloth loop to each other in the upper base fabric portion,
The lower base cloth temporary core wire is inserted into the front lower base cloth loop and the rear lower base cloth loop to join each other, and the upper base is inserted into the front upper base cloth loop and the rear upper base cloth loop to join each other. The step of inserting the cloth temporary core wire and
The step of needling short fibers to the base cloth to form the butt fiber layer,
After removing the temporary core wire of the upper base cloth, a step of heating and drying the base cloth and the butt fiber layer in a state where tension in the mechanical direction is applied to the base cloth, and
The lower base fabric temporary core wire is removed, and the butt fiber layer is separated along the adjacent portions of the front and rear lower base fabric loops and the overlapping portions of the front and rear upper base fabric loops. A method characterized by comprising a step of making an end. The weaving step includes weaving the upper base cloth warp into the upper base cloth weft so as to be folded back at the weaving core wire by using the upper base cloth weft as a warping yarn and the upper base cloth warp as a driving yarn.
The total thickness of the upper base cloth temporary core wire inserted through the front upper base cloth loop and the rear upper base cloth loop is the thickness of the upper base cloth loop inserted through the front side upper base cloth loop and the rear side upper base cloth loop. The method according to claim 5, wherein the core wire for weaving is thinner than the entire thickness. The neighboring portions fixed to each other are sewing machines within a range of 1 cm to 20 cm in the mechanical direction from the boundary between the lower base fabric portion and the front lower base fabric loop and the front upper base fabric loop in the upper base fabric portion. The method of claim 5 or 6, characterized in that it has been sewn. The method according to any one of claims 5 to 7, further comprising a step of performing a heat pressurization treatment in the thickness direction on the base fabric on which the butt fiber layer is formed.