JP4185091B2 - Shoe press belt for papermaking - Google Patents

Description

  The present invention relates to a papermaking belt such as a shoe press belt and a sheet transfer belt used in an open type paper press shoe press machine.

  As shown in FIG. 3, an open type shoe press belt used for a paper making shoe press machine is used for a shoe press held between a plurality of rolls between a top (press) roll 41 and a shoe 42 as shown in FIG. The belt 43 is run, and a wet paper 46 sandwiched between the top felt 44 and the bottom felt 45 is placed on the shoe press belt 43, and the pressure formed between the top roll 41 and the shoe 42 is moistened. The paper 46 can be reliably conveyed and squeezed.

  Further, a sheet transfer belt for the purpose of realizing a closed draw for enabling a high speed machine is used as shown in FIG. That is, the wet paper web 46 is formed on the forming wire 50 and is separated by the pickup felt 53 that goes around the pickup roll 54 having a suction ground between the couch roll 51 and the turning roll 52. The wet paper 46 attached to the lower side of the pickup felt 53 is carried to a press nip N formed between the upper press roll 57, the lower press roll 56, the pickup felt 53, and the sheet transfer belt 55. In the press nip N, the moisture in the wet paper 46 is transferred to the pickup felt 53. Accordingly, the wet paper web 46 is separated from the pickup felt 53 by the guide roll 58 on the exit side of the press nip N. Next, the wet paper 46 adheres to the sheet transfer belt 55 and moves to the second press nip N-2. Since the sheet transfer belt 55 has a smooth surface and does not allow water to pass therethrough, the rewetting phenomenon from the felt to the wet paper 46 as in the case of using the felt does not occur. Thereafter, the wet paper is squeezed again by the upper press roll 60, the lower press roll (also using a shoe and a press belt) 61, the press felt 59, and the sheet transfer belt 55 in the second press nip N-2. . Thereafter, the wet paper web 46 is separated from the sheet transfer belt 55 by the guide roll 58 'and moves to the dry part. During this time, the wet paper web 46 is moved with the aid of the felt or sheet transfer belt 55, so that paper breakage hardly occurs and the paper making speed is increased.

  In the open type papermaking shoe press machine, just before the belt 43 enters the shoe 42, lubricating oil is sprayed to the inside of the belt 43 by an oil spray device 47, and the friction between the inner surface of the belt 43 and the shoe 42. The resistance can be lowered. The sprayed lubricating oil is scraped off at the exit of the shoe 42 by a scraper 48 and an oil scraping brush 49.

Regarding papermaking belts, there are JP-B-63-38477, JP-A-4-82888, JP-A-5-311591, JP-B-3-64639 and JP-B-63-15398.
JP-B 63-38477 Japanese Patent Laid-Open No. 4-82888 Japanese Patent Publication No. 3-64639 JP-B 63-15398

  However, among the open type belts, the one-side coated belt has both ends A and B in use due to a so-called bimetal phenomenon due to a difference in heat shrinkage between the base material layer and the resin layer being manufactured. a) There was a tendency to curl to the shoe side (downward) as indicated by the one-dot chain line. On the other hand, the transfer belt used for conveying the belt surface in direct contact with the sheet has a tendency to curl toward the felt side resin layer as indicated by the alternate long and short dash line in FIG.

  In other words, the resin layer is applied to the base material layer in a liquid form by mixing one or two liquids, but it hardens and shrinks, and if it is a heat-coated type resin, it is coated in a thermally expanded state. The amount of shrinkage of the resin was further increased, and the curl at the belt edge was further increased.

  The curl sizes C1 and C2 vary depending on the combination of the base material layer and the resin layer as shown in FIG. 5, but are usually about 30 to 100 mm. Since the gap G is generated, the scraping ability by the scraper 48 is deteriorated. The curl lengths L1 and L2 are found to be about 100 mm as shown in FIG.

  As described above, in the papermaking belt, if the scraper 48 does not scrape the lubricating oil, the lubricating oil remaining on the inner surface of the belt collides with a belt roll (for example, indicated by the symbol R in FIG. 3) located behind the scraper. As a result of the centrifugal force of the roll, oil mist is scattered around the machine, increasing the amount of oil used and increasing the cost, as well as causing oil contamination around the machine and the problem of oil contamination in the drainage.

  Also, if both ends of the belt are curled as shown by the alternate long and short dashed lines in FIGS. 6A and 6B, the contact of the edge of the belt with the guide palm becomes unstable, which affects belt running performance. In addition, various problems have occurred, for example, when the belt is hooked into the machine, the belt ear is caught on the belt hooking side end of the roll and it takes time to hook the belt.

  None of the above Japanese Patent Publication Nos. Sho 63-38477, Japanese Laid-Open Patent Publication Nos. Hei 4-82888, Japanese Laid-Open Patent Publication No. Hei 5-311591, Japanese Patent Publication No. Hei 3-64639 and Japanese Examined Publication No. Sho 63-15398 have no knowledge regarding curling of both end edges.

  The present invention is intended to solve the above-mentioned various problems. The object of the present invention is to use a belt for an open type for a difference in heat shrinkage between a base layer of a single-side coated belt and a resin layer, and for sheet transfer. It is an object of the present invention to provide a papermaking belt that can reduce or eliminate the curling of the belt edge caused by the difference in heat shrinkage between the base material layer and the resin layer of the single-side coated belt.

In order to achieve the above object, the invention according to claim 1 is a shoe press belt for papermaking in which a resin layer is formed on a shoe contact side which is a lower part of a base material layer during machine running. the widthwise end portions to the central portion, or polished thin within a range that does not cause a gap between the scraper in contact after passing the shoe portion to the resin layer, that there have is polished from the central portion continuously tapered A papermaking shoe press belt characterized in that the invention according to claim 2 is a papermaking sheet transfer belt in which a resin layer is formed on a pickup belt side which is an upper part of a base material layer during machine running. The end of the resin layer in the width direction with respect to the central portion is thinly polished within a range that does not cause a gap with the scraper in contact with the resin layer, or the central portion A sheet transfer belt for papermaking, characterized in that polished continuously tapered, but to reduce the widthwise end portions in order to make it difficult to occur bimetal phenomenon, so as not to cause a gap between the scraper did.

According to the present invention, in papermaking shoe press belt made by forming a resin layer on the shoe contacting side, which is the lower part of the base layer when the machine running, the both widthwise end portions to the central portion of the resin layer, the resin or polished thin within a range that does not cause a gap between the scraper in contact after passing the shoe portion to the layer, it is have is a shoe press bell papermaking, characterized in that polished from the central portion continuously tapered Therefore, the bimetal phenomenon hardly occurs in the single-side coated belt of the shoe press belt for papermaking, and the curl at both ends of the belt can be greatly improved . In addition, since there is no gap between the paper press shoe press belt and the scraper at both ends, it has excellent oil scraping performance, no oil splattering, and greatly reduced oil consumption . There is an effect.

According to a second aspect of the present invention, in the sheet transfer belt for papermaking, wherein the resin layer is formed on the pickup belt side which is the upper part of the base material layer during machine running, both ends in the width direction with respect to the central portion of the resin layer Since the sheet transfer belt for papermaking is characterized in that the part is polished thinly in a range that does not cause a gap with the scraper in contact with the resin layer or is continuously polished from the center part, Bimetal phenomenon is less likely to occur in single-side coated belts for sheet transfer belts, and curl at both ends of the belt can be greatly improved. In addition, there are no gaps between the paper transfer sheet transfer belt and the scraper at both ends, and excellent effects such as good scraping performance by the scraper can be obtained.

  Next, an embodiment of the present invention will be described based on the drawings shown in FIGS. That is, as shown in FIG. 1A, the belt 1 of the present application includes a base layer 2 and a resin layer 3 formed on the lower portion (shoe side) of the base layer 2 (single-side coated belt). 3, both end portions A and B in the width direction are formed thinner than the central portion C.

  Further, as shown in FIG. 1B, the belt 1 of the present application includes a base material layer 2 and a resin layer 3 formed on the upper side (felt side) of the base material layer 2 (single-side coated belt). 3, both end portions A and B in the width direction are formed thinner than the central portion C.

  For the base material layer 2, for example, both warp and weft yarns are 0.4mmφ polyester monofilament yarn, and the middle part (filling yarn) is polyester multifilament yarn (3000d), and the structure is 3/1, 1/3 core. The one formed by entering double weave is used.

  The resin layer 3 in the single-side coated belt can be satisfied by using a urethane resin. The reason why the width-direction end portions A and B are formed thinner than the central portion C is to make the so-called bimetal phenomenon difficult to occur. As a method of forming the both end portions A and B thinner than the central portion C, it is preferable to polish using a polishing machine. Of course, if there is any means other than polishing, it is free to use it.

  Both the warp and weft are 0.4mmφ polyester monofilament yarn for the base material layer, and the polyester multifilament yarn (3000d) is used for the middle part (filling yarn). Then, using a woven fabric woven to a thickness of 1.9 mm, impregnate the urethane resin from the shoe contact surface side of the woven fabric and apply until the total thickness is 3.5 mm, and then heat to apply urethane. The resin was cured, and after curing, the resin layer was polished until the total thickness became 3.0 mm (resin layer 1.1 mm) to obtain a comparative belt “I” (single-side coated belt) [FIG. 2 (a). Reference: After polishing and turning over for use as a shoe press belt.

  Next, the resin layer at both ends in the width direction of the single-side coated belt shown in the comparative belt “I” is polished to a thickness of 0.5 mm from the end edge to the inside of 100 mm (0.6 mm thinner than the central portion). ) To obtain a belt “I” of this application [see FIG. 2 (b): after polishing and turning over for use as a shoe press belt].

  The resin layers at both ends in the width direction of the single-side coated belt shown in the comparative belt “a” are continuously made to have a thickness of 0.5 mm at the edge, and the same thickness as the center at 100 mm inside the edge. Polished into a taper shape (thinner is thinner than the center part) and applied to the belt “b” (see FIG. 2 (c): after being turned over after polishing for use as a shoe press belt). Obtained.

  When the curl amounts (C1, C2 in FIG. 5) of the end edges of the comparative belt “I” and the present belt “I”, “B” were measured, the comparative belt “I” was 60 mm. In contrast, the belt “I” of the present application was 10 mm, and the belt “B” of the present application was 20 mm. As a result, it was found that the curl at both ends of the belt was greatly improved.

  In the actual test, the belts “I” and “B” of the present application were not particularly problematic. Since the belts “I” and “B” of the present application have the resin layers polished at both ends, there is a concern that the polished portion will separate from the scraper after passing through the shoe portion, and the oil cannot be scraped off. The difference in thickness between the center part and the center part may be as small as 0.6 mm (further smaller in the belt “B” of the present application), and it is not a problem because it is scraped off by the oil scraping brush located after the scraper. Accordingly, the oil was not scattered and the amount of oil used was greatly reduced from 60 L / day to 10 L / day. In addition, the running performance and the machine insertion performance were good because both ends of the belt were not curled inward.

  Although the above description is for the case where the resin layer is on the back surface (the shoe contact surface side), the same can be said for the case where the resin layer is on the surface.

It is sectional drawing which shows the case where a part of center part of the width direction of this-application belt is abbreviate | omitted, (a) is a back surface single-sided coated belt, (b) is a surface single-sided coated belt. FIG. 3 is a cross-sectional view schematically showing the shape of one end of a single-side coated belt, where (a) is a comparative belt “I”, (b) is a belt “A” of the present application, and (c) is a belt “B” of the present application. It is a schematic explanatory drawing of the open type shoe press machine for papermaking. It is a schematic explanatory view showing an example of use of a seat transfer belt. FIG. 6 is a schematic explanatory view showing a curl amount and a length generated at both ends of an open type shoe press belt. It is sectional drawing which shows the case where a part of center part of the width direction of the conventional belt (comparison belt) is abbreviate | omitted, (a) is a back surface single-sided coated belt, (b) is a surface single-sided coated belt. It is a schematic explanatory drawing which shows the relationship between a conventional belt (comparison belt) and a scraper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 This application belt 2 Base material layer 3 Resin layer 41 Top (press) roll 42 Shoe 43 Open type shoe press belt 43a Base material layer 43b Thick resin layer 43c Thin resin layer 44 Top felt 45 Bottom felt 46 Wet paper 47 Oil spray Equipment 48 Scraper 49 Oil scraping brush 50 Forming wire 51 Couch roll 52 Turning roll 53 Pickup felt 54 Pickup roll 55 Sheet transfer belt 56 Lower press roll 57 Upper press roll 58, 58 'Guide roll 59 Press felt 60 Upper press roll 61 Lower part Press roll A, B Width direction both ends C Center part G Gap N Press nip N-2 Second press nip R Belt roll

Claims (2)

In a shoe press belt for papermaking, in which a resin layer is formed on the shoe contact side , which is the lower part of the base material layer when the machine is running, both ends in the width direction with respect to the central part of the resin layer pass through the shoe part to the resin layer papermaking shoe press belt or polishing thin in a range not causing gaps, there have, characterized in that the polished from the central portion continuously tapered between the scraper in contact with the post.   In a sheet transfer belt for papermaking in which a resin layer is formed on the pickup belt side which is an upper part of a base material layer during machine running, both widthwise end portions with respect to the central portion of the resin layer are connected to a scraper in contact with the resin layer. A sheet transfer belt for papermaking, wherein the belt is thinly polished as long as no gap is formed between them, or is continuously polished from the center.

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