JP2007100277A - Papermaking transfer felt for shoe press and press apparatus of shoe press-type papermaking machine equipped with the papermaking transfer felt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a papermaking transfer felt for a shoe press, enabling stains to be easily removed, excellent in a smoothing function of a surface of wet paper, and having a good paper-separating function, when the wet paper is delivered, and to provide a press apparatus of a shoe press-type papermaking machine, equipped with the papermaking transfer felt. <P>SOLUTION: This papermaking transfer felt 100 for the shoe press is equipped with a base layer 11, a first batt layer 13A formed on a surface of the base layer 11 on a side of wet paper W, a second batt layer 13B formed on a surface of the base layer 11 on a side of a roll or on a side of a shoe, a wet paper-contacting fiber layer 15 containing a hydrophilic fiber and formed on a surface of the first batt layer 13A on a side of the wet paper W, so as to directly contact with the wet paper W. The hydrophilic fiber is fibrillated by being pressurized by the roll and the shoe. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper press felt for shoe press (hereinafter referred to as “paper press felt for shoe press” or simply “paper transport felt”) and a press of a shoe press type paper machine provided with the paper feed felt. Relates to the device.

  The press part of the shoe press type paper machine is provided with a press device. The press device includes a plurality of press mechanisms arranged in series along a wet paper web transfer direction. Each press mechanism has a pair of endless belt-shaped paper transport felts, and rolls and shoes (that is, shoe presses) that are vertically opposed to sandwich a part of each of the paper transport felts. The wet paper transported by the paper transporting felt traveling in the same direction at approximately the same speed is pressed with a roll and a shoe together with the paper transporting felt to squeeze moisture from the wet paper (that is, However, the paper transport felt absorbs the moisture.

  According to the press mechanism equipped with the shoe press described above, the roll and the shoe are compared with the press mechanism equipped with a more general roll press (that is, a pair of rolls instead of a combination of a roll and a shoe). Since the press zone of the pressurization part (namely, nip) formed by this can be made wide and the pressurization time can be lengthened thereby, it is excellent in water squeezing more.

  However, in the part from the center of the pressurizing part between the roll and the shoe to the outlet, the pressure applied to the wet paper and the paper transport felt is suddenly released, so in this part the paper transport felt and the wet paper The volume expands rapidly. As a result, a negative pressure is generated in the paper transporting felt and the wet paper. Further, since the wet paper is made of fine fibers, a capillary phenomenon is also added, so that the water absorbed in the paper transporting felt is transferred to the wet paper again. A re-wetting phenomenon occurs. Thus, the part from the center of the pressurization part between a roll and a shoe to an exit becomes a big factor which reduces the squeezing performance of the press apparatus of a shoe press type paper machine.

  In order to improve water-squeezing performance, a press felt for papermaking in which a hydrophilic non-woven fabric is disposed in a bat layer to suppress the occurrence of a rewetting phenomenon is known (for example, see Patent Document 1). Examples of the hydrophilic non-woven fabric are composed by laminating fibers formed by melting and spinning a resin, for example, a spunbond non-woven fabric obtained by laminating continuous filaments, and stretching a molten polymer with hot air. Non-woven fabric made into a fine fiber and sheet-like can be mentioned.

  Since the hydrophilic non-woven fabric has a higher density and lower water permeability than the bat fiber, the moisture in the bat layer disposed on the roll side (or shoe side) of the hydrophilic non-woven fabric in the papermaking press felt is a hydrophilic non-woven fabric. It hardly penetrates and moves to the bat layer and the wet paper on the wet paper side. Therefore, the hydrophilic nonwoven fabric suppresses the return of moisture in the bat fiber of the bat layer on the roll side (or shoe side) to the wet paper. In addition, since the fineness of the hydrophilic nonwoven fabric is lower than the fineness of the vat layer, the moisture in the vat layer arranged on the wet paper side of the hydrophilic nonwoven fabric is easily transferred to the hydrophilic nonwoven fabric by capillary action. Rewetting phenomenon is prevented.

JP 2004-143627 A

  In the press device of a shoe press type paper machine, compared with the one using a roll press, the paper transporting felt is squeezed by applying a very large pressure to the paper transporting felt at the pressurizing part (that is, the nip). The result is that flattening is likely to be high density. Accordingly, dirt (specifically, components such as additives and glues contained in the wet paper) adhere to and accumulate on the paper transport felt. Therefore, in the press device of a shoe press type paper machine, the life of the paper transporting felt (that is, the usable period of the paper transporting felt) is shortened. Therefore, the paper transporting felt is frequently replaced with a new one or in the middle of paper making. Maintenance such as cleaning the paper transport felt is required.

  In addition, in the press device of a shoe press type paper machine, the fiber on the surface of the butt layer that is in direct contact with the wet paper of the paper transporting felt due to a very large pressure and friction at the pressurizing part (ie, nip). Dropping off or cutting off (that is, so-called hair removal) occurs remarkably. Most of the fibers that have fallen off and the fibers that have been cut off are discharged out of the press apparatus by a cleaning means such as a water shower and a suction box, but some of them may adhere to the surface of the wet paper. Since the dropped fibers and the cut fibers are thicker and harder than the wet paper fibers, the paper manufactured while the fibers are attached to the surface (that is, papermaking) may have poor printability. (More specifically, color loss may occur when printing). As described above, the hair removal on the surface of the batt layer that directly contacts the wet paper of the paper transporting felt deteriorates the quality of paper products such as printed matter. On the other hand, the surface of the bat layer becomes rough due to the hair removal of the fibers, which is a factor that significantly reduces the surface smoothness of the wet paper.

  The main functions required for the paper transport felt for shoe presses include not only the wet paper transport function and the water squeezing function, but also the wet paper surface smoothing function and the wet paper delivery as is apparent from the above. A good paper separation function is also required. The press felt for papermaking disclosed in Patent Document 1 mainly focuses on the improvement of water-squeezing performance, and improves the smoothness of the wet paper surface required for the production of high-quality paper, It does not contribute at all to improve separation.

  The present invention has been made in view of the above-described circumstances, and the object thereof is to easily remove dirt, to have an excellent smoothing function on the surface of a wet paper, and to have a good paper separation function at the time of delivery of the wet paper. An object of the present invention is to provide a paper press felt for shoe press and a press device for a shoe press type paper machine provided with the paper feed felt.

In order to achieve the above-described object, a paper press felt for shoe press according to the present invention and a press device for a shoe press type paper machine provided with the paper feed felt are characterized by the following (1) to (6).
(1) It is disposed in a press device provided in a press part of a shoe press type paper machine, and forms a press mechanism together with a shoe press having a roll and a shoe in the press device, and the roll and It is at least one papermaking felt of a pair of papermaking felts for a shoe press that absorbs moisture squeezed from the wet paper by being pressed by the shoe, and includes a base layer and the wet paper of the base layer A first bat layer formed on the surface of the side, a second bat layer formed on the roll side or shoe side surface of the base layer, and hydrophilic fibers, and so as to be in direct contact with the wet paper A wet paper web contact fiber layer formed on the wet paper web surface of the first batt layer, wherein the hydrophilic fiber is pressed by the roll and the shoe. To be fibrillated.
(2) Fibers forming the wet paper contact fiber layer of the paper transporting felt for shoe presses having the structure of (1) are composed of 15% to 100% by weight of the hydrophilic fibers and the remaining non-hydrophilic fibers. .
(3) The papermaking felt for shoe press configured as described in (1) or (2) above includes a hydrophilic nonwoven fabric layer between the base layer and the wet paper web contact fiber layer.
(4) A press device of a shoe press type paper machine provided with a paper press felt for shoe press having the structure of any one of (1) to (3) above.
(5) A press apparatus for a shoe press type paper machine comprising a plurality of the press mechanisms having the paper transporting felt for shoe presses having the constitution of (1) or (2), wherein the plurality of press mechanisms are those Are arranged in series along the transport direction of the wet paper transported by the paper transport felt.
(6) A press apparatus for a shoe press type paper machine comprising a plurality of the press mechanisms having the paper transporting felt for shoe presses configured as described in (1) or (2) above, wherein the plurality of press mechanisms are (3) in the press mechanism that is arranged in series along the transport direction of the wet paper transported by the paper transporting felt and arranged downstream of the transport direction among the plurality of press mechanisms. The paper transport felt for the shoe press of

According to the paper transporting felt for shoe presses having the structure of (1) above, wet paper containing hydrophilic fibers that are fibrillated by press with a shoe press (that is, rolls and shoes) to become fibrils. Since the contact fiber layer is formed on the surface of the first butt layer of the paper transporting felt so as to be in direct contact with the wet paper, the hydrophilic property becomes a fibril having a very low fineness by fibrillation. If the wet paper contact fiber layer containing fibers is formed, the surface smoothness of the wet paper can be improved. In addition, stains temporarily adhering to the paper transporting felt (specifically, components such as additives and glue contained in the wet paper) are caused by the so-called depilation phenomenon of fibrils formed by fibrillation of hydrophilic fibers. Since the fibrils fall off the paper transporting felt together with the fibrils, it is difficult for the paper transporting felt to remain dirty. Even if fibrils that have fallen off or cut off from the wet fiber contact fiber layer (that is, fibrils formed by fibrillation of hydrophilic fibers) adhere to the surface of the wet paper, the fibrils are very thin, so the wet paper In addition, the dirt that partially migrates to the wet paper when the fibrils formed by fibrillation fall off is originally contained as a component in the wet paper, so the quality of the wet paper Will not be affected. Therefore, the paper produced by the shoe press type paper machine using the paper press felt for shoe press has a very smooth surface, and the life of the paper feed felt (that is, the paper feed felt can be used) Period) becomes longer. Therefore, it is possible to reduce the frequency of maintenance such as replacing the paper transporting felt with a new one or cleaning the paper transporting felt in the middle of papermaking. Therefore, it is desirable that the hydrophilic fiber is included in at least the surface of the wet paper web contact fiber layer that comes into direct contact with the wet paper.
It should be noted that the fibrillation of the hydrophilic fibers in the wet paper contact fiber layer of the paper transporting felt for shoe presses according to the present invention is immediately performed during the trial operation (ie, so-called leveling operation) of the press device of the shoe press type paper machine. Therefore, high-quality papermaking can be stably performed from the beginning of the papermaking operation, and the time until the papermaking operation is stabilized can be greatly shortened. By the way, it is preferable that the hydrophilic fiber used in the paper press felt for shoe press according to the present invention is a fiber that is fibrillated by being pressed by the shoe press as described in (1) above. In the carding process and the needling process, which are felt manufacturing processes, a relatively thick state is maintained without fibrillation. For example, if a hydrophilic fiber that is fibrillated into small fibers during carding is carded, a fiber lump (that is, a lump of fibers) is easily formed. The fiber lump is planted in the felt in the needling process, and irregularities are formed on the surface of the paper transporting felt, so that the surface smoothness of the wet paper decreases. Therefore, such a problem can be overcome by using a wet paper web contact fiber layer containing hydrophilic fibers that are fibrillated by press with a shoe press and become fibrils.
According to the paper transporting felt for shoe presses having the configuration of (2) above, the fibers forming the wet paper contact fiber layer are composed of 15% to 100% by weight of hydrophilic fibers and the remaining non-hydrophilic fibers. By appropriately changing the weight ratio of the conductive fibers, the characteristics of the papermaking felt for shoe press can be changed. Here, the weight ratio of the hydrophilic fiber is defined as “weight of hydrophilic fiber / (weight of hydrophilic fiber + weight of non-hydrophilic fiber) × 100”. The non-hydrophilic fiber is a normal fiber that is not fibrillated even in the carding process, the needling process, or by pressing with a shoe press (that is, a roll and a shoe).
Surface smoothness and water squeezing, which are characteristics required for paper press felt for shoe presses, are inversely related, and the density of paper press felt for shoe presses is increased to improve the smoothing performance of the wet paper surface. And water squeezing tends to be worse. On the other hand, a plurality of press mechanisms arranged from the upstream to the downstream in the conveyance direction of the wet paper to be transported are required to have slightly different functions, and the paper conveyance felt of the press mechanism arranged on the upstream side is squeezed. Water-based printing is important, and the paper transporting felt of the press mechanism disposed on the downstream side is required to have a smoothing performance on the surface of the wet paper. Therefore, by appropriately changing the weight ratio of the hydrophilic fibers, the paper transporting felt can have characteristics (surface smoothness, water squeezing, etc.) optimum for each press mechanism.
According to the paper transporting felt for shoe presses having the configuration of (3) above, since the hydrophilic nonwoven fabric layer is provided between the base layer and the wet paper contact fiber layer, the paper transporting felt is once absorbed from the wet paper. Retransfer of water to wet paper (that is, so-called rewetting phenomenon) is prevented by the hydrophilic nonwoven fabric layer.
According to the press device of the shoe press type paper machine having the configuration of the above (4), since the paper transporting felt for shoe press of any one of the above (1) to (3) is provided, the excellent operation and effect as described above. Play.
A shoe press type paper machine provided with a plurality of press mechanisms having a paper press felt for shoe presses having the structure of (1) or (2) as in the press device of the shoe press type paper machine having the structure of (5). In particular, if the plurality of press mechanisms are arranged in series (that is, juxtaposed) in series along the transport direction of the wet paper transported by the paper transport felt, Therefore, it is suitable for efficiently squeezing water. That is, according to the press device of the shoe press type paper machine having the configuration of the above (5), a large amount of water can be effectively squeezed out from the wet paper containing a large amount of water. Since a good paper separation function at the time of delivery can be provided, papermaking operation at high speed becomes possible.
As in the press device of the shoe press type paper machine having the configuration of (6) above, the paper transporting felt of (3) above is disposed on the press mechanism disposed on the downstream side in the wet paper transport direction among a plurality of press mechanisms. If this is the case, the paper permeability of the paper transport felt of the above (3) may not only be smooth, but the water permeability may be slightly lower than the paper transport felt of the above (1) and (2). Since it has a high rewet preventing function, it is particularly suitable for preventing the rewet phenomenon and smoothing the wet paper surface.

  According to the present invention, there is provided a paper transport felt for a shoe press and a paper transport felt for a shoe press that are easy to remove dirt and have an excellent smoothing function on the surface of the wet paper, and further have a good paper separation function during delivery of the wet paper. A press device for a shoe press type paper machine can be provided.

  The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading through the best mode for carrying out the invention described below with reference to the accompanying drawings.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of a first embodiment of a papermaking felt for shoe presses according to the present invention (papermaking felt 100 for shoe presses), and FIG. 2 shows a first embodiment of a papermaking felt for shoe presses according to the present invention. FIG. 3 is a schematic view for explaining one embodiment of a press device of a shoe press type paper machine according to the present invention. FIG. 3 is a longitudinal sectional view of a second embodiment (paper press felt 200 for shoe press).

(First embodiment)
As shown in FIG. 1, a papermaking felt 100 for shoe press includes a base layer 11, a butt layer 13 (first butt layer 13A and second butt layer 13B), and a wet paper web contact fiber layer 15. . More specifically, the first butt layer 13A is formed on the surface of the base layer 11 on the wet paper side, the second butt layer 13B is formed on the roll side or shoe side surface of the base layer 11, and is in direct contact with the wet paper. As described above, the wet paper web contact fiber layer 15 is formed on the wet paper web surface of the first batt layer 13A. The base layer 11, the batt layer 13 (the first batt layer 13A and the second batt layer 13B), and the wet paper web contact fiber layer 15 are intertwined and integrated by needling.

The base layer 11 is for imparting strength to the paper transporting felt 100. For example, synthetic fibers such as nylon 6, nylon 66, and the like excellent in wear resistance, fatigue resistance, stretch characteristics, antifouling properties, and the like. Further, a woven fabric made of natural fibers such as wool, etc., a material obtained by superimposing yarn materials without being woven, or a film-like material can be appropriately used. In the present embodiment, the base layer 11 is woven. The basis weight of the base layer 11 is 550 g / m ² , the thickness of the base layer 11 is 1.5 mm, and the density of the fibers forming the base layer 11 is 0.367 g / cm ³ .

The batt layer 13 (the first batt layer 13A and the second batt layer 13B) is a normal fiber layer formed by staple fibers 17 having a fineness of 6 dtex or more (generally about 17 dtex). The basis weight of the bat layer 13 is 500 g / m ² , and more specifically, the basis weight of the first bat layer 13A is 400 g / m ² , and the basis weight of the second bat layer 13B is 100 g / m ² . The thickness of the first batt layer 13A is 0.9 mm, and the density of the staple fibers 17 forming the first batt layer 13A is 0.444 g / cm ³ . The thickness of the second batt layer 13B is 0.4 mm, and the density of the staple fibers 17 forming the second batt layer 13B is 0.250 g / cm ³ . As the material for forming the bat layer 13, a material similar to that of the base layer 11 is appropriately used. The second butt layer 13B may be omitted depending on the characteristics required for the papermaking felt 100.

The wet paper contact fiber layer 15 is made of a hydrophilic fiber (in other words, the hydrophilic fiber occupies 100% by weight of the wet paper contact fiber layer 15). The hydrophilic fiber forming the wet paper contact fiber layer 15 is a fiber that is fibrillated into a plurality of small fibers by the pressing action of a press device of a shoe press type paper machine, and preferably has a fineness of 10 dtex or less. In the embodiment, a fiber having a fineness of 6 dtex is used. The reason why the fineness of the hydrophilic fiber is set to 10 dtex or less is mainly for facilitating the formation of the wet paper contact fiber layer 15, specifically, the car manufacturing process of the papermaking felt 100 itself. The hydrophilic fiber is not fibrillated in the bonding process and the needling process, and the paper transporting felt 100 is effectively applied by the pressing action of the shoe press (roll and shoe) when the paper transporting felt 100 is mounted on a press device of a shoe press type paper machine. This is to make it fibrillated. The basis weight of the wet paper web contact fiber layer 15 is 100 g / m ² , the thickness of the wet paper web contact fiber layer 15 is 0.20 mm, and the density of the hydrophilic fibers forming the wet paper web contact fiber layer 15 is 0.500 g / cm. ³ . The fibrillation of the hydrophilic fiber will be described in detail later. The wet paper contact fiber layer 15 may be a fiber containing 15% to 100% by weight of hydrophilic fiber and the remaining part being non-hydrophilic fiber. Here, the non-hydrophilic fiber is a normal fiber that is not fibrillated even in the carding process, the needling process, or by pressing with a shoe press (that is, a roll and a shoe). Moreover, as a normal fiber, the staple fiber which has the fineness of 6 dtex (namely, the same value as the fineness before fibrillation of a hydrophilic fiber)-20 dtex is desirable, for example. Fibrilization is a phenomenon in which the fibrils (small fibers) inside the fibers appear on the surface due to friction and become fluffy.

  As the hydrophilic fiber, cellulosic fibers such as rayon, polynosic, cupra, cotton, hemp, silk and the like are preferable, and among them, rayon is particularly preferable. Here, the hydrophilicity is to have at least one of the property of attracting moisture and the property of retaining moisture.

  A specific example of hydrophilicity is that the fiber is hygroscopic. In this case, when the fiber absorbs moisture, an affinity acts between the water and the fiber. In addition, as a characteristic of the hydrophilic fiber suitable for the paper transporting felt 100 of the present embodiment, the official moisture content is 4.0% or more, preferably 5.0% or more. The official moisture content of the hydrophilic fibers described above is 11.0% rayon, 11.0% polynosic, 11.0% cupra, 8.5% cotton, 12.0% hemp, and 12.0% silk. . Here, the official moisture content is a numerical value obtained based on the formula for calculating the “official moisture content” described in JIS L0105 (General rules for physical test methods for textile products).

A method for manufacturing the paper transporting felt 100 will be briefly described. First, a material in which the bat layer 13 is integrated on both surfaces of the woven base layer 11 by needling or the like is prepared. Then, after the carded hydrophilic fiber web sheet is placed on the surface of the first batt layer 13A, the hydrophilic fiber web sheet, the batt layer 13 and the base layer are formed so that the wet paper web contact fiber layer 15 is formed. 11. Needle through 11 and entangle. Needles used for needling are, for example, 36th thick, 2 barbs 6 ridges, approximately 0.1 mm in barb depth, and approximately 0.04 mm in diameter at the tip of the needle. Was used, and the needle depth was 7 to 16 mm and the number of needlings was 650 / cm ² .

  In the carding step, the hydrophilic fiber can maintain its fineness of 6 dtex, and for example, it is possible to prevent the generation of fiber mass that occurs when carding is performed in a fibrillated state. Also in the needling step, the thickness of the needle tip (approximately 0.04 mm in diameter) and the depth of the barb for hydrophilic fibers having a diameter of approximately 0.03 mm (calculated from a fineness of 6 dtex). Both (approximately 0.1 mm) are sufficiently large (in other words, because the hydrophilic fibers are very thin), the hydrophilic fibers move away from the needle tip during needle sticking in the needling process, and the needles are hydrophilic. There is almost no stab at the sex fiber. Further, the hydrophilic fiber that contacts the barb enters the barb that is sufficiently larger than the thickness of the hydrophilic fiber, and is hardly fibrillated by the barb. Therefore, the wet paper web contact fiber layer 15 (that is, the hydrophilic fiber) is not fibrillated by needling, and the wet paper web contact fiber layer having a smooth surface while the majority remains thick (6 dtex). 15 is obtained.

The basis weight of the paper transporting felt 100 thus manufactured is 1150 g / m ² , the thickness of the paper transporting felt 100 is 3.00 mm, and the density of the entire fibers forming the paper transporting felt 100 is 0.383 g / cm ^3. It is. In addition, in the paper transporting felt 100, the density of the entire fibers in the other layers other than the wet paper contact fiber layer 15 is 0.375 g / cm ³ (basis weight is 1050 g / m ² ). The air permeability of the paper transporting felt 100 is 8 cc / cm ² / sec (this value is an average value of values measured by applying a pressure of 125 Pa to a test piece of the paper transporting felt 100 by the Frazier method based on JIS L 1096. .)

  When the wet paper contact fiber layer 15 is mounted on a press device of a shoe press type paper machine and travels, the wet paper contact fiber layer 15 is fibrillated into small fibers by pressurization by a press action of a roll and a shoe (shoe press). As a result, the paper transporting felt 100 having the wet paper contact fiber layer 15 with a smooth surface covered with small fibers is formed. The fibrillation of the hydrophilic fibers forming the wet paper contact fiber layer 15 is performed by showering the paper transporting felt 100 during the trial operation of the press device of the shoe press type paper machine (that is, so-called leveling operation). In advance, the water soaked in the paper transporting felt 100 by spraying with water is pressurized with a roll and a shoe (shoe press) while sucking it with a suction box (that is, a cleaning means), before the actual paper making. It is preferable to complete the fibrillation of the hydrophilic fiber.

  In addition, in order to make the paper transporting felt 100 having the optimum characteristics according to the type of paper to be made, the types of fibers forming the base layer 11, the batt layer 13, and the wet paper contact fiber layer 15 are respectively or in combination. It is appropriately selected in consideration of the characteristics at the time.

(Modification of paper transport felt 100)
As a preferred modification of the paper transporting felt 100, there is provided a wet paper contact fiber layer comprising 50% by weight of 6 dtex hydrophilic fibers and the balance (ie, 50% by weight) of 10 dtex non-hydrophilic fibers. List what you have. In this case, the average thickness of the fibers forming the wet paper contact fiber layer is about 8 dtex. The base layer 11 and the bat layer 13 are the same as described above. Since the wet paper contact fiber layer contains non-hydrophilic fibers that are not fibrillated into fibrils, the wet paper contact fiber layer does not become too dense, and appropriate water permeability is ensured. Can be squeezed effectively.

(Second Embodiment)
Next, a shoe press papermaking felt 200 according to a second embodiment of the present invention will be described with reference to FIG. In addition, about the component similar to 1st Embodiment already demonstrated (namely, papermaking felt 100 for shoe presses), the same code | symbol or an equivalent code | symbol is attached | subjected in a figure, and description is simplified or abbreviate | omitted.

  As shown in FIG. 2, the shoe press paper transporting felt 200 includes a base layer 11 and a butt layer 13 (first butt layer 13A and second butt layer) in the same manner as the shoe press paper transporting felt 100 described above. 13B) and a wet paper web contact fiber layer 15, and only a shoe press is provided with a hydrophilic nonwoven fabric layer 23 in the first batt layer 13A between the base layer 11 and the wet paper web contact fiber layer 15. This is different from the paper transport felt 100 for printing.

More specifically, the second butt layer 13B is formed on the surface of the base layer 11 on the roll side or the shoe side, and the first portion 13Aa of the first butt layer 13A is formed on the surface of the base layer 11 on the wet paper web side. A hydrophilic nonwoven fabric layer 23 is formed on the wet paper web side surface of the first portion 13Aa of the batt layer 13A, and a second portion 13Ab of the first batt layer 13A is formed on the wet paper web surface of the hydrophilic nonwoven fabric layer 23, The wet paper web contact fiber layer 15 is formed on the wet paper web surface of the second portion 13Ab of the first batt layer 13A so as to be in direct contact with the wet paper, and these are intertwined and integrated by needling. . The basis weight of the paper transporting felt 200 is 1350 g / m ² , the thickness of the paper transporting felt 200 is 3.50 mm, and the density of the entire fibers forming the paper transporting felt 200 is 0.386 g / cm ³ . The basis weight of the hydrophilic nonwoven fabric layer 23 is 50 g / m ² , the thickness of the hydrophilic nonwoven fabric layer 23 is 0.1 mm, and the density of the fibers forming the hydrophilic nonwoven fabric layer 23 is 0.500 g / cm ³ . In addition, in the papermaking felt 200, the density of the entire fibers of the other layers other than the wet paper contact fiber layer 15 is 0.379 g / cm ³ (basis weight is 1100 g / m ² ). The air permeability of the paper transporting felt 200 configured as described above is 4 cc / cm ² / sec (this value is a value measured by applying a pressure of 125 Pa to a test piece of the paper transporting felt 200 by the Frazier method based on JIS L 1096. Is the average value.) Note that the wet paper web contact fiber layer 15 may be formed on the wet paper web surface of the hydrophilic nonwoven fabric layer 23 without forming the second portion 13Ab of the first batt layer 13A.

  The hydrophilic nonwoven fabric layer 23 is formed of a hydrophilic nonwoven fabric having a high density by laminating fibers having a fineness of 4 dtex or less, for example, thinner than the fibers forming the batt layer 13. As an example of the hydrophilic nonwoven fabric forming the hydrophilic nonwoven fabric layer 23, it is constituted by laminating fibers obtained by melting and spinning a resin such as nylon, for example, spunbond formed by laminating continuous filaments. Nonwoven fabrics, nonwoven fabrics obtained by drawing molten polymer with hot air into fine fibers, and the like.

  In order to effectively prevent rewetting, the hydrophilicity of the hydrophilic nonwoven fabric layer 23 is such that when the moisture content of the hydrophilic nonwoven fabric layer 23 is adjusted to 30 to 50%, the contact angle with water is 30 °. The following is desirable. In addition, the moisture content of the hydrophilic nonwoven fabric layer 23 is calculated | required from (water / whole weight) x100.

(Modification of paper transporting felt 200)
As a preferred modification of the paper transporting felt 200, the basis weight of the paper transporting felt is 1350 g / m ² , the thickness of the paper transporting felt is 3.56 mm, and the density of the entire fiber forming the paper transporting felt is 0.379 g / cm ³ , the basis weight of the base layer is 650 g / m ² , the thickness of the base layer is 1.7 mm, and the density of the fibers forming the base layer is 0.382 g / cm ³ , and the staple fiber has a fineness of 3.3 dtex The basis weight of the bat layer formed by 17 is 450 g / m ² (more specifically, the basis weight of the first bat layer is 300 g / m ² and the basis weight of the second bat layer is 150 g / m ² ). The thickness of the first batt layer is 0.8 mm, the density of the staple fibers 17 forming the first batt layer is 0.375 g / cm ³ , and the thickness of the second batt layer is 0.6 m. m, the density of the staple fiber 17 forming the second batt layer is 0.250 g / cm ³ , the basis weight of the wet paper contact fiber layer made of 3 dtex hydrophilic fibers is 200 g / m ² , and the wet paper contact The thickness of the fiber layer is 0.36 mm, the density of the hydrophilic fiber forming the wet paper contact fiber layer is 0.556 g / cm ³ , and the basis weight of the hydrophilic nonwoven fabric layer is 50 g / m ² , hydrophilic An example is one in which the thickness of the nonwoven fabric layer is 0.1 mm and the density of the fibers forming the hydrophilic nonwoven fabric layer is 0.500 g / cm ³ . In the modified example of the paper transporting felt 200, the density of the entire fibers of the other layers other than the wet paper contact fiber layer is 0.359 g / cm ³ . The air permeability of the modified example of the paper transporting felt 200 is 3 cc / cm ² / sec.

  Next, a press apparatus 300 of a shoe press type paper machine equipped with a paper press felt 100 for shoe press formed in an endless belt (annular) and a paper press felt 200 for shoe press will be described with reference to FIG. To do.

  As shown in FIG. 3, the press device 300 of the shoe press type paper machine includes two press mechanisms, a first press mechanism 51 and a second press mechanism 53, along the wet paper W conveyance direction (arrow A direction). Is a so-called closed draw type press apparatus 300 arranged in series. A closed draw type shoe press type paper machine in which the wet paper W is transported and pressed while being sandwiched between a pair of shoe press paper transport felts 100 and a pair of shoe press paper transport felts 200 is used. Thus, the wet paper web W can be stably conveyed at a high speed of 1200 to 1400 m / min, for example. As a result, paper can be made with extremely high efficiency as compared with an open draw type shoe press type paper machine.

  The first press mechanism 51 includes a first shoe 55 and a first shoe arranged to face each other so as to form a pair of shoe press papermaking felts 100 for shoe presses and a first nip (in other words, a first pressure unit). 1 roll 57 (in other words, the 1st shoe press). The second press mechanism 53 includes a second shoe 59 and a second shoe which are arranged to face each other so as to form a pair of shoe press papermaking felts 200 for a shoe press and a second nip (in other words, a second pressure unit). 2 rolls 61 (in other words, a second shoe press).

As shown in FIG. 3, the paper transporting felt 100 may be employed as the upper and lower paper transporting felts of the first press mechanism 51, or may be employed in either the upper or lower paper transporting felt. When the paper transporting felt 100 is mounted as either one of the upper and lower paper transporting felts of the first press mechanism 51, any one of the upper and lower paper transporting felts of the first press mechanism 51 is selected according to the paper making characteristics. A transport felt may be employed.
Similarly, as shown in FIG. 3, the papermaking felt 200 may be employed as the upper and lower papermaking felts of the second press mechanism 53, or may be employed as either the upper or lower papermaking felt. When the paper transporting felt 200 is mounted as one of the upper and lower paper transporting felts of the second press mechanism 53, the upper and lower paper transporting felts of the second press mechanism 53 have any paper making according to the paper making characteristics. A transport felt may be employed.
Further, only the paper transporting felt 100 or only the paper transporting felt 200 may be employed as the paper transporting felt of the first press mechanism 51 and the second press mechanism 53.
Furthermore, only the paper transporting felt 100 or only the paper transporting felt 200 may be employed as the paper transporting felt of the second press mechanism 53. In this case, the paper transporting felt of the first press mechanism 51 has a papermaking characteristic. In addition, any paper transport felt may be employed.

  By performing so-called leveling operation of the press device 300 of the shoe press type paper machine, the hydrophilic fibers of the wet paper contact fiber layer 15 of the paper transporting felt 100 and the paper transporting felt 200 are fibrillated. That is, each wet paper web contact fiber layer 15 (that is, hydrophilic fiber) is placed between the first shoe 55 and the first roll 57 and between the second shoe 59 and the second roll 61 by the leveling operation. By being pressurized when passing through, it is fibrillated into fibrils, and the wet paper web surface of the papermaking felts 100 and 200 becomes a smooth surface. The pressurizing condition by the first shoe 55 and the first roll 57 for the paper transporting felt 100 is 800 kN / m, and the pressurizing condition by the second shoe 59 and the second roll 61 for the paper transporting felt 200 is 1050 kN / m. It is. The shoe width is 10 inches for both the first shoe 55 and the second shoe 59, and the traveling speed of each of the paper transporting felt 100 and the paper transporting felt 200 is 1700 m / min.

  As shown in FIG. 3, the wet paper W carried out from the wire part (not shown) and delivered to the first press mechanism 51 is conveyed while being sandwiched between the pair of papermaking felts 100, and the first shoe Water is squeezed by being pressurized by 55 and the first roll 57, and the squeezed water is absorbed by the papermaking felt 100. Next, the wet paper W is transferred to the second press mechanism 53 and conveyed while being sandwiched between the pair of papermaking felts 200, and further pressed by being pressed by the second shoe 59 and the second roll 61. The squeezed water is absorbed by the paper transporting felt 200. At this time, the surface of the wet paper web W that contacts the wet paper web contact fiber layer 15 is smoothed, transferred to a dryer part (not shown), and dried.

  When the pressure acting on the wet paper W and the paper transporting felt 200 is released from the second pressure part of the second shoe 59 and the second roll 61 to the outlet, the moisture in the paper transporting felt 200 becomes wet paper. Although the rewetting phenomenon that shifts to the W side is about to occur, the hydrophilic nonwoven fabric layer 23 has a higher density and a lower water permeability than the batt layer 13, so the second shoe 59 side or the second side of the hydrophilic nonwoven fabric layer 23. The moisture in the second vat layer 13B arranged on the two-roll 61 side hardly penetrates the hydrophilic nonwoven fabric layer 23 and moves to the first vat layer 13Ab on the wet paper web W side. Thereby, generation | occurrence | production of a rewet phenomenon is suppressed. Moreover, since the fineness of the hydrophilic nonwoven fabric layer 23 is lower than the fineness of the bat layer 13, the moisture in the second portion 13Ab of the first bat layer 13A disposed on the wet paper web side from the hydrophilic nonwoven fabric layer 23 is a capillary phenomenon. Is transferred to and held by the hydrophilic nonwoven fabric layer 23. Therefore, the rewetting phenomenon can be effectively prevented.

  As described above, as an example, the press apparatus 300 including the two-stage press mechanisms 51 and 53 has been described as an embodiment of the press apparatus of the shoe press type paper machine according to the present invention. Needless to say, it may be a press device provided or a press device in which a large number of press mechanisms are arranged in series (that is, arranged in parallel).

  As described above, according to the paper transporting felt (100; 200) for shoe press, the fibril is pressed by the shoe press (that is, the roll (57; 61) and the shoe (55; 59)). Of the first butt layer 13A of the paper transporting felt (100; 200) so that the wet paper contact fiber layer 15 containing hydrophilic fibers that are further converted into small fibers directly contacts the wet paper W. Since it is formed on the surface, if the wet paper web contact fiber layer 15 including hydrophilic fibers that become fibrils with extremely low fineness is formed by fibrillation, the surface smoothness of the wet paper W can be improved. it can. In addition, stains temporarily attached to the paper transport felt (100; 200) (specifically, components such as additives and glues contained in the wet paper W) are formed by fibrillation of hydrophilic fibers. The so-called hair removal phenomenon of the fibers causes the fibers to fall off the paper transporting felt (100; 200) together with the fibrils, so that it is difficult for dirt to remain on the paper transporting felt (100; 200). Even if the fibrils (that is, fibrils formed by fibrillation of hydrophilic fibers) are slightly attached to the surface of the wet paper W due to falling off or cutting off from the wet paper contact fiber layer 15, the fibrils are extremely thin. Therefore, the quality of the wet paper W is not deteriorated, and moreover, dirt that partially migrates to the wet paper as the fibrils formed by fibrillation fall off is originally contained as a component in the wet paper W. The quality of the wet paper web W is not affected at all. Therefore, the paper produced by the shoe press type paper machine using the shoe press paper transport felt (100; 200) has an extremely smooth surface, and in addition, the paper transport felt (100; 200) The service life, that is, the usable period of the paper transport felt is increased. Accordingly, it is possible to reduce the frequency of maintenance such as replacing the paper transporting felt (100; 200) with a new one or cleaning the paper transporting felt in the middle of papermaking. Therefore, it is desirable that the hydrophilic fiber is included in at least the surface of the wet paper web contact fiber layer 15 that is in direct contact with the wet paper W.

  Further, according to the press device 300 of the shoe press type paper machine, if the paper transporting felt 100 is disposed on the press mechanism 51 disposed on the upstream side in the transporting direction A of the wet paper W among the plurality of press mechanisms 51 and 53. In particular, it is suitable for efficiently squeezing water from the wet paper W. That is, according to the press device 300 of the shoe press type paper machine having this configuration, a large amount of water can be effectively squeezed out from the wet paper containing a lot of water, and thus, the paper transport felt (100; 200) can be used. Since a good paper separation function can be provided at the time of wet paper delivery, papermaking operation at high speed is possible.

Moreover, according to the papermaking felt 200 for shoe press, since the hydrophilic nonwoven fabric layer 23 is provided between the base layer 11 and the wet paper contact fiber layer 15, the papermaking felt 200 is once absorbed from the wet paper W. The re-transfer of the moisture to the wet paper web W (that is, the so-called re-wetting phenomenon) is prevented by the hydrophilic nonwoven fabric layer 23.
Further, according to the press device 300 of the shoe press type paper machine, if the paper transporting felt 200 is disposed on the press mechanism 53 disposed on the downstream side in the transport direction A of the wet paper W among the plurality of press mechanisms 51 and 53. Although the water permeation performance may be slightly lower than that of the paper transport felt 100, the paper transport felt 200 not only has a smoothing function on the wet paper surface but also has a high re-wetting prevention function. Suitable for preventing and smoothing the wet paper surface.

  Moreover, according to the paper transporting felt for shoe press (100; 200), the fineness before fibrillation of each hydrophilic fiber is 10 dtex or less, so that the fineness before fibrillation of the hydrophilic fiber is 10 dtex. Even if it exists, the fineness of the fibril formed by the fibrillation of the hydrophilic fiber becomes smaller than 10 dtex. As a result, if the wet paper contact fiber layer 15 including hydrophilic fibers that become small fibers with a fineness close to the fineness of the fibers of the wet paper W is formed, a high-quality paper having excellent surface smoothness can be produced. can do. Further, it is more preferable that the fineness of each hydrophilic fiber before fibrillation is as small as 6 dtex.

  In addition, when the fiber forming the wet paper contact fiber layer 15 contains 15% to 100% by weight of hydrophilic fiber and the remaining part is non-hydrophilic fiber, the weight ratio of the hydrophilic fiber is appropriately changed. By doing so, the characteristics of the papermaking felt (100; 200) for shoe press can be changed. Here, the weight ratio of the hydrophilic fiber is defined as “weight of hydrophilic fiber / (weight of hydrophilic fiber + weight of non-hydrophilic fiber) × 100”. Surface smoothness and water squeezability, which are characteristics required for a papermaking felt (100; 200) for shoe presses, are inversely proportional to each other, and in order to improve the smoothing performance of the wet paper W surface, papermaking for shoe presses is performed. When the density of the transport felt (100; 200) is increased, the squeezing property tends to be deteriorated. On the other hand, a slightly different function is required for each of the plurality of press mechanisms 51 and 53 arranged from the upstream side to the downstream side in the conveyance direction of the wet paper W to be conveyed, and the papermaking of the press mechanism 51 arranged on the upstream side is required. The transport felt 100 places importance on water squeezing, and the paper transport felt 200 of the press mechanism 53 disposed on the downstream side is required to have a smoothing performance on the surface of the wet paper web W. Therefore, by appropriately changing the weight ratio of the hydrophilic fibers, the paper transporting felts 100 and 200 can have the optimum characteristics (surface smoothness, water squeezing, etc.) for the press mechanisms 51 and 53, respectively.

  Further, according to the press device 300 of the shoe press type paper machine, since it is a closed draw type press device, the wet paper web W is transported in a state of being sandwiched between a pair of shoe press paper transport felts (100; 200). Is done. Accordingly, the wet paper web W can be conveyed at an extremely high speed without being stretched (no load). Therefore, efficient papermaking becomes possible.

  The fibrillation of the hydrophilic fibers of the wet paper contact fiber layer 15 of the shoe press paper transporting felt (100; 200) is performed during a trial operation (ie, so-called leveling operation) of the press device 300 of the shoe press type paper machine. It is desirable to be done. The hydrophilic fibers used in the paper press felt (100; 200) for the shoe press are preferably fibers that are fibrillated by being pressed by the shoe press, and a carding step that is a paper transport felt manufacturing step. In the needling process, it remains relatively thick without being fibrillated. For example, if a hydrophilic fiber that is fibrillated into small fibers during carding is carded, a fiber lump is easily formed. The fiber lump is planted in the felt in the needling process, and irregularities are formed on the surface of the paper transporting felt, so that the surface smoothness of the wet paper decreases. Therefore, such a problem can be overcome by using the wet paper web contact fiber layer 15 including hydrophilic fibers that are fibrillated by pressing with a shoe press and become fibrils.

  Note that the present invention is not limited to the above-described embodiments and modifications, and modifications, improvements, and the like can be made as appropriate. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the embodiment and the modification described above are arbitrary and are not limited as long as the present invention can be achieved.

  For example, even when a paper press felt (100; 200) for shoe press is mounted on an open draw type shoe press type paper machine having a portion where the wet paper web W is transported independently during the transport, the same effect is obtained. To do.

  Further, in the present embodiment, the case where the present invention is applied to the press device of a shoe press type paper machine is shown, but the present invention is not limited to this, and the roll press type paper machine having a pair of rolls that pressurize the paper transport felt. You may apply this invention to a press apparatus.

It is a longitudinal cross-sectional view of 1st Embodiment of the paper conveyance felt for shoe presses concerning this invention. It is a longitudinal cross-sectional view of 2nd Embodiment of the papermaking felt for shoe presses concerning this invention. It is the schematic for demonstrating one Embodiment of the press apparatus of the shoe press type | mold paper machine which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Paper transport felt for shoe press 200 Paper transport felt for shoe press 300 Press device of shoe press type paper machine 11 Base layer 13 Butt layer 13A First butt layer 13B Second butt layer 15 Wet paper contact fiber layer 23 Hydrophilic nonwoven fabric Layer 51 Press mechanism disposed on the upstream side of the wet paper transport direction 53 Press mechanism disposed on the downstream side of the wet paper transport direction A Transport direction of the wet paper W Wet paper

Claims (6)

It is arranged in a press device provided in a press part of a shoe press type paper machine, forms a press mechanism together with a shoe press having a roll and a shoe in the press device, and uses the roll and the shoe while sandwiching wet paper. At least one paper transporting felt of a pair of shoe presses for a shoe press that absorbs moisture squeezed from the wet paper,
The base layer,
A first batt layer formed on the wet paper web surface of the base layer;
A second butt layer formed on the roll side or shoe side surface of the base layer;
A wet paper web layer containing hydrophilic fibers and formed on the wet paper side surface of the first batt layer so as to be in direct contact with the wet paper;
With
A paper transport felt for a shoe press, wherein the hydrophilic fiber is fibrillated by being pressed by the roll and the shoe.   The paper transporting felt for shoe press according to claim 1, wherein the fibers forming the wet paper contact fiber layer are composed of 15% to 100% by weight of the hydrophilic fiber and the remaining non-hydrophilic fiber.   The paper transporting felt for shoe press according to claim 1 or 2, further comprising a hydrophilic nonwoven fabric layer between the base layer and the wet paper contact fiber layer.   The press apparatus of the shoe press type paper machine provided with the paper transport felt for shoe presses as described in any one of Claims 1-3.   A press apparatus for a shoe press type paper machine comprising a plurality of the press mechanisms having the paper transport felt for shoe press according to claim 1 or 2, wherein the plurality of press mechanisms are configured to transport the paper transport. A press apparatus for a shoe press type paper machine, which is arranged in series along a conveyance direction of wet paper conveyed by a felt. A press apparatus for a shoe press type paper machine comprising a plurality of the press mechanisms having the paper transport felt for shoe press according to claim 1 or 2, wherein the plurality of press mechanisms are configured to transport the paper transport. It is arranged in series along the transport direction of the wet paper transported by the felt,
4. A press for a shoe press type paper machine, wherein a paper transporting felt for a shoe press according to claim 3 is disposed in a press mechanism disposed downstream of the transport direction among the plurality of press mechanisms. apparatus.

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