JP5406732B2 - Ceramic roll for paper making process - Google Patents

Description

  The present invention relates to a ceramic roll used when dehydrating wet paper in a press part or the like in a paper making process.

  In the paper making process in papermaking, it is necessary to remove a large amount of water contained in the wet paper that has been made and dry it. As a method for removing moisture from the wet paper, a press part is usually provided that dehydrates the wet paper held on the felt between two rolls and pressurizes in the paper making process. As a roll used in this press part, a roll having a hard surface is used as at least one of the two rolls for dehydration by pressurization and imparting smoothness to the wet paper surface.

  The above-mentioned roll with a hard surface is required to be a material that can withstand high loads, high-speed rotation, and long-term use, and stone rolls using natural granite have been used for a long time. Since this stone roll can be mirror-finished, it has a high smoothness-imparting function on paper and has high surface hardness, so it has low wear and can withstand the above-mentioned high loads, high-speed rotation and long-term use. Is possible. However, since stone rolls are made of natural stone, they are becoming difficult to obtain. In addition, it is extremely difficult to quarry, transport and process large stones for press rolls that are long and large. Furthermore, since the stone roll is a natural material, there is a disadvantage that the surface characteristics such as hardness vary for each roll to be manufactured or for each portion of one roll.

  Therefore, ceramic rolls having a ceramic layer sprayed on the surface by a gas plasma spraying method or the like are being widely adopted as rolls instead of stone rolls. Since such a ceramic roll has a dense ceramic layer provided on the surface by thermal spraying, the roll surface is highly smooth.

  This ceramic roll having a high surface smoothness can improve the paper surface smoothness, while the adhesiveness between the roll surface and the wet paper becomes too high, and the paper peelability is lowered. Thus, when paper peelability is low, when a wet paper passes a press roll, a wet paper surface part may peel off. The debris on the surface of the wet paper that has been peeled off adheres to the roll surface, which causes a reduction in paper quality. In addition, if the peelability from the paper is low, a paper break may occur in the process after the press roll, and the production line may be stopped.

  When such a ceramic roll is used for a long time in a press part, the surface is gradually worn by contact with the wet paper and the smoothness is increased, and in addition, the roll central portion is worn and the surface tends to be curved.

  Accordingly, in order to control the smoothness of the surface of the ceramic roll, the surface is polished so as to have an appropriate surface roughness in the manufacturing process and in the regular maintenance (Japanese Patent Laid-Open No. 9-9 / 1999). 241820). As this surface polishing method, for example, after rough polishing, finish polishing is performed with a polishing grindstone or a polishing film. In this finish polishing, in the case of a polishing grindstone, a polishing film having a particle size of # 120 to # 1000 is used. In this case, by using particles made of abrasive particles of 15 μm to 100 μm, the level difference (Rk) of the core part, the load length ratio (Mr2) of the core part, and the protruding valley part depth (Rvk) are obtained as the surface roughness. A control method has been proposed (see Japanese Patent Application Laid-Open No. 2005-273090).

  However, according to the roll for the papermaking process in which the surface roughness of the roll surface is simply controlled by using a specific abrasive as described above, the pulp fibers on the wet paper surface are easily clogged by scratches caused by polishing. There is a limit to increasing the peelability. Therefore, it is desired to develop a ceramic roll having a higher paper releasability while having a function of imparting smoothness to paper in a press part or the like in the paper making process.

JP-A-9-241820 JP 2005-273090 A

  The present invention has been made in view of these circumstances, and aims to provide a ceramic roll having a high peelability from paper while having a function of imparting smoothness to paper in a press part or the like in a papermaking process. To do.

The invention made to solve the above problems is
A ceramic roll for paper making process comprising a ceramic layer on the outer peripheral surface side,
Having scratches on the ceramic layer surface,
The main direction of the scratch eye has a directional region that is inclined with respect to the circumferential direction.

  According to the ceramic roll for papermaking process, since the main direction of the scratches has a directional area inclined with respect to the circumferential direction of the roll, in the press part of the papermaking process, the papermaking moisture in this directional area is The fiber orientation direction of the paper and the main direction of the scratches can be different directions. Therefore, according to the ceramic roll, the pulp fiber on the wet paper surface is less likely to be buried in the fine scratches in the directional region, so that it is possible to improve the peelability from the paper while imparting smoothness to the paper. it can.

  It is preferable that the directional region has a belt-like shape having the main direction of the scratch as a longitudinal direction, and the directional regions are arranged at regular intervals along the axial direction. According to the ceramic roll, the directional regions are arranged at regular intervals along the axial direction as described above, so that the directional regions and other regions are alternately provided in the axial direction. . Therefore, according to the ceramic roll, it is possible to prevent the pulp fibers from being buried together in the scratches and to further improve the peelability of the paper.

  The directional region is preferably formed in a zigzag shape along the circumferential direction. According to the ceramic roll, since the directional region is formed in a zigzag shape along the circumferential direction, the fiber orientation direction of the wet paper is determined by the presence of the conversion portion in the main direction in the directional region. Even when the difference from the main direction of the scratch is small, the fibers are less likely to be buried in the scratch. Therefore, according to the ceramic roll, the peelability of the paper can be further improved.

  The inclination angle with respect to the circumferential direction in the main direction of the scratch eye is preferably 4 ° or more and 60 ° or less. The ceramic roll can effectively improve the peelability of the paper because the main direction of the scratch is inclined in the above range.

  The arithmetic average roughness (Ra) of the outer peripheral surface of the ceramic roll is preferably 0.2 μm or more and 2 μm or less. According to the ceramic roll, by setting the arithmetic average roughness (Ra) of the outer peripheral surface in the above range, it is possible to improve the peelability of the paper without reducing the smoothness of the wet paper to be pressed.

  Here, the “scratch eyes” refer to fine streak-like polishing marks formed by polishing using an abrasive such as a grindstone or a polishing film. “Arithmetic average roughness (Ra)” is a value measured according to JIS-B0601 (1994) with a cutoff λc of 2.5 mm and an evaluation length of 12.5 mm.

  As explained above, according to the ceramic roll for papermaking process, in the press part in the papermaking process, high wetness can be imparted to the wet paper, and in addition, the peelability from the wet paper can be improved, Quality deterioration can be prevented and the yield can be improved.

The schematic diagram which shows the ceramic roll for papermaking processes which concerns on one Embodiment of this invention. The typical partial enlarged view which shows the surface of the ceramic roll for papermaking processes of FIG. The typical partial enlarged view which shows the surface of the ceramic roll for papermaking processes different from the ceramic roll for papermaking processes of FIG. The schematic diagram which shows the grinding | polishing method of the ceramic roll for papermaking of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
The ceramic roll 1 for paper making process in FIG. 1 mainly includes a roll body 2 and a ceramic layer 3 laminated on the outer peripheral surface side of the roll body 2.

  As the roll main body 2, one that is generally employed in a press part in the paper making process can be used. The roll main body 2 is formed of a cast steel roll shell 4 formed in a cylindrical shape and having a predetermined thickness, a disk-shaped head 5 fitted to both ends of the roll shell 4, and the center of each head 5. And a shaft 6 projecting outward.

The ceramic layer 3 is laminated on the outer peripheral surface of the roll shell 4. It does not specifically limit as a ceramic which forms this ceramic layer 3, A well-known thing can be used. Further, the thickness of the ceramic layer 3 is not particularly limited. The ceramic layer 3 can be laminated, for example, by spraying ceramic powder obtained by mixing titania (TiO ₂ ) at a ratio of 10 to 65% with respect to alumina (Al ₂ O ₃ ).

  The ceramic roll 1 has scratches on the surface of the ceramic layer 3, that is, the entire outer peripheral surface. The scratches are formed by polishing the outer peripheral surface with an abrasive.

  The ceramic roll 1 has a directional region 7 in which the main direction (the arrow direction in FIG. 2) of the scratch is inclined with respect to the circumferential direction (vertical direction in FIG. 2) of the roll 1. The scratches are formed, for example, by polishing with a polishing film having abrasive grains attached thereto, as will be described later. In the directional region 7, scratches having a direction different from the main direction may be mixed.

  In addition, the directionality of the scratches in the region other than the directionality region 7 on the outer peripheral surface of the ceramic roll 1 is not particularly limited. Examples of the scratches other than the directionality region 7 include, for example, random directions, a mixture of scratches composed of a plurality of directions, non-linear scratches, and the like. Scratch eyes having different main directions may be used.

  According to the ceramic roll 1, since the main direction of the scratches has the directional region 7 that is inclined with respect to the circumferential direction of the roll in this way, in the press part of the papermaking process, The main direction of the eyes can be different from the main fiber orientation direction of the wet paper. This is because the fiber orientation direction in the paper made is basically the flow direction in the paper making process, that is, the circumferential direction of the ceramic roll 1 in the press part. Therefore, according to the ceramic roll 1, the pulp fibers on the surface of the wet paper are less likely to be buried in the fine scratches in the directional region 7 even when the wet paper that has been made is pressed. Peelability can be improved.

  As shown in the enlarged view of FIG. 2, the directional region 7 has a belt-like shape with the main direction of the scratch eye (the arrow direction in FIG. 2) as the longitudinal direction. In addition, this strip | belt-shaped shape means the substantially rectangular shape which has a fixed width | variety, For example, the shape where the corner | angular of the vertex is taken may be sufficient even if it is not strictly a rectangle. The directional regions 7 are arranged at regular intervals along the axial direction of the ceramic roll 1 (lateral direction in FIG. 2).

  According to the ceramic roll, the directional regions 7 are arranged at regular intervals along the axial direction in this way, so that the directional regions 7 and other regions are alternately provided in the axial direction. It becomes. Therefore, when this ceramic roll 1 is used in the press part of the papermaking process, the portion in contact with the directional region 7 and the region other than the directional region 7 are in contact with the wet paper surface at the moment of leaving the roll surface. There will be a part that is. That is, according to the ceramic roll, even if the pulp fiber coincides with the main direction of the scratches in the directional region 7 on the surface of the wet paper, and the pulp fibers are buried in the scratches, this direction. Since the regions other than the sex region 7 are close to each other, the pulp fibers buried in the scratches can be kept to a very small part. That is, according to the ceramic roll 1, it is possible to prevent a certain amount of pulp fibers from being collected and buried in the scratches, and further improve the peelability of the paper.

  Although it does not specifically limit as a width | variety of this directional area | region 7, 2 mm or more and 20 mm or less are preferable, and 3 mm or more and 10 mm or less are more preferable. The interval between the directional regions 7 (the width of the region other than the directional region 7) is not particularly limited, but is preferably 2 mm or more and 20 mm or less, and more preferably 3 mm or more and 10 mm or less. By providing such a width and interval of the directional region 7, the releasability from the paper can be effectively improved. If the width and interval of the directional region 7 are smaller than the above range, the formation workability of such a scratch eye is lowered, but the peelability from the paper may not be improved. Further, if the width and interval of the directional region 7 are larger than the above range, a certain amount of pulp fibers are easily collected and buried in the directional region 7 or the scratches in the other regions, so that the peelability from the paper is high. May not improve.

  Further, the length of the directional region 7 is not particularly limited. For example, the entire outer peripheral surface may be formed of a single spiral directional region 7, or conversely, a strip-shaped directional property. It may be a set of regions 7.

  The directional region 7 has a belt-like shape as described above, and is formed in a zigzag shape along the circumferential direction of the roll 1 (vertical direction in FIG. 2). According to the ceramic roll 1, the directional region 7 is formed in a zigzag shape along the circumferential direction in this way, and therefore there is a main direction conversion portion in the directional region 7. Therefore, when the ceramic roll is used for a press part, even if the difference between the fiber orientation direction of the wet paper and the main direction of the scratch is small, the fibers are not easily buried in the scratch. Become. That is, even when the main direction of the scratch eye of the directional region 7 and the fiber orientation direction of a certain pulp fiber coincide with each other, in the above-mentioned conversion point, the main direction of the scratch eye is different from the direction. Pulp fiber burial can be confined to one or part of a small amount of fiber. Therefore, according to the ceramic roll 1, it is possible to further improve the peelability from the paper.

  The size of the zigzag shape in the directional region 7 is not particularly limited. For example, the zigzag repeating unit length (the length between the direction change points) is preferably 5 mm or more and 50 mm or less, and more preferably 10 mm or more and 40 mm or less. When the zigzag shape is the above size, the paper peelability of the ceramic roll 1 can be further effectively improved.

  The lower limit of the inclination angle with respect to the circumferential direction of the main direction of the scratch eye in the directional region 7 is preferably 4 °, more preferably 10 °, and even more preferably 15 °. On the other hand, the upper limit of the inclination angle is preferably 60 °, more preferably 50 °, and even more preferably 40 °. According to the ceramic roll 1 having such a scratch angle, the peelability from the paper can be improved more effectively. When this inclination angle is smaller than the lower limit, the difference between the fiber orientation direction of the wet paper and the main direction of the scratches in the directional region 7 becomes small, and the pulp fibers are easily buried in the scratches, and are peeled off from the paper. May not improve. On the other hand, when this inclination angle is larger than the above upper limit, it becomes difficult to form such a steep inclination angle, while the effect of improving the peelability from paper reaches a peak.

  The lower limit of the arithmetic average roughness (Ra) of the outer peripheral surface of the ceramic roll 1 is preferably 0.2 μm, more preferably 0.4 μm, further preferably 0.6 μm, and particularly preferably 0.8 μm. On the other hand, the upper limit of the arithmetic average roughness (Ra) is preferably 2 μm, more preferably 1.6 μm, still more preferably 1.4 μm, and particularly preferably 1.2 μm. According to the ceramic roll 1, the arithmetic average roughness (Ra) of the outer peripheral surface is in the above range, so that the paper releasability can be improved without reducing the smoothness of the pressed wet paper. When the arithmetic average roughness (Ra) of the outer peripheral surface is smaller than the above lower limit, the smoothness is too high and the paper releasability may be reduced. On the other hand, when the arithmetic average roughness (Ra) exceeds the above upper limit, the smoothness of the wet paper surface to be pressed is lowered, and the quality of the obtained paper may be lowered.

  The lower limit of the maximum height (Ry) of the outer peripheral surface of the ceramic roll 1 is preferably 4 μm, and more preferably 6 μm. On the other hand, the upper limit of the maximum height (Ry) is preferably 12 μm, and more preferably 10 μm. If the maximum height (Ry) of the outer peripheral surface of the ceramic roll 1 is smaller than the lower limit, the smoothness is too high and the peelability from the wet paper is lowered. On the contrary, when the maximum height (Ry) exceeds the upper limit, the smoothness of the wet paper to be pressed is lowered, and the paper quality may be lowered.

  The lower limit of the ten-point average roughness (Rz) of the outer peripheral surface of the ceramic roll 1 is preferably 4 μm, and more preferably 6 μm. On the other hand, the upper limit of the ten-point average roughness (Rz) is preferably 12 μm, and more preferably 10 μm. If the ten-point average roughness (Rz) of the outer peripheral surface of the ceramic roll 1 is smaller than the lower limit, the smoothness is too high and the peelability from the wet paper may be reduced. On the contrary, when the ten-point average roughness (Rz) exceeds the upper limit, the smoothness of the wet paper to be pressed is lowered, and the quality of the paper may be lowered.

  The maximum height (Ry) and ten-point average roughness (Rz) are the same as arithmetic average roughness (Ra), according to JIS-B0601 (1994), with a cutoff λc of 2.5 mm and an evaluation length of 12. It is a value measured at 5 mm.

  The arithmetic average roughness (Ra), maximum height (Ry), and ten-point average roughness (Rz) of the outer peripheral surface are preferably in the above ranges regardless of the directional region 7 and other regions. The arithmetic average roughness (Ra), the maximum height (Ry), and the ten-point average roughness (Rz) are five positions at regular intervals in the horizontal direction of the ceramic roll 1 (when there are portions to be polished at both ends). And the average value measured at a total of 20 locations of 4 locations at approximately equal intervals in the circumferential direction. Each surface roughness can be measured using, for example, SJ-201P manufactured by Mitutoyo Corporation.

  3 has a directional region 17 having a shape different from that of the directional region 7 of the ceramic roll 1. The directional region 17 has a strip shape with the main direction (the arrow direction in FIG. 3) of the scratch eye as the longitudinal direction. The directional regions 17 are arranged at regular intervals along the axial direction of the ceramic roll 11 (lateral direction in FIG. 3). Furthermore, this directional area | region 17 is arrange | positioned along the circumferential direction (vertical direction in FIG. 3) of the ceramic roll 11 at zigzag form.

  The ceramic roll 11 also has a directional region 17 in which the main direction of the scratches is inclined with respect to the circumferential direction of the roll, and this directional region further takes the shape and arrangement described above. When used in the press part in the process, high peelability from the wet paper can be exhibited.

  Next, the manufacturing method of the said ceramic roll 1 for papermaking processes is demonstrated.

The ceramic roll is obtained by laminating a ceramic layer on the surface of the roll body 2 by a known method, or a roll whose outer peripheral surface is smoothed by using an existing ceramic roll as a press part for a papermaking process for a long time. It can manufacture by grinding | polishing with the following grinding | polishing processes. This polishing step includes the following steps.
(1) Rough polishing step for roughening the outer peripheral surface of the ceramic roll for paper making process (2) Pre-finishing step for adjusting the roughness of the outer peripheral surface of the ceramic roll that has undergone the rough polishing step Directional region forming step for forming scratches inclined with respect to the circumferential direction on the outer circumferential surface

  Hereinafter, each step will be specifically described.

(1) Rough polishing step In this rough polishing step, a flat outer peripheral surface is roughened to a certain level using a diamond grindstone or the like. As a polishing method using this diamond grindstone, for example, the ceramic roll can be rotated in the circumferential direction, and the diamond grindstone can be brought into contact with the outer peripheral surface of the ceramic roll. The surface roughness (Ra) of the outer peripheral surface of the ceramic roll that has undergone this rough polishing step is, for example, about 1.7 μm to 2.2 μm.

(2) Intermediate finishing step In this intermediate finishing step, the roughness is adjusted so that the surface roughened in the rough polishing step has a surface roughness suitable as a ceramic roll for papermaking. For the polishing in the intermediate finishing step, for example, a finisher device using a diamond film as an abrasive can be used. This finisher device is a device that bridges a belt-shaped diamond film between a plurality of rollers and polishes while rotating the plurality of rollers. Polishing using the finisher device is performed by rotating the ceramic roll in the circumferential direction and bringing a diamond film attached to the finisher device into contact with the outer peripheral surface of the ceramic roll through one roll of the finisher device.

  As the diamond film used in the intermediate finishing step, a polyester base cloth laminated with diamond grains having a grain size of # 320 to # 1000 is suitably used. In addition, it is preferable to use a plurality of diamond films having different particle sizes and perform polishing a plurality of times to adjust to a desired surface roughness. The surface roughness (Ra) of the outer peripheral surface of the ceramic roll that has undergone such an intermediate finishing step is, for example, about 1.1 μm to 1.2 μm.

(3) Directional region forming step In this directional region forming step, a directional region is formed on the outer peripheral surface of the ceramic roll that has been adjusted to a certain degree of surface roughness through the intermediate finishing step. As shown in FIG. 4, the polishing in the directional region forming step can be performed using the finisher device 21 as in the above (2) intermediate finishing step. In this directional region forming step, the zigzag directional region 7 is formed by using a cross hatch film 22 in which abrasive grains are adhered in a cross hatch shape on a base cloth and used between a plurality of rollers 23. Can be formed.

  As the base fabric of the cross hatch film 22, for example, a cloth knitted with synthetic fibers (polyester fibers or the like) and cotton soaked in a resin solution to increase the strength is used. Moreover, it does not specifically limit as a cross hatch shape of this cross hatch film 22, For example, rectangular shape and square shape are mentioned. The size when the cross hatch is square is preferably about 2 to 10 mm, and more preferably about 3 to 7 mm. The cross hatch is arranged in a grid pattern with an interval of 2 to 3 mm.

  Polishing in the directional region forming step is also performed by rotating the ceramic roll in the circumferential direction and bringing the cross hatch film 23 attached to the finisher device 21 into contact with the outer peripheral surface of the ceramic roll. At this time, the finisher device 21 can form the directional region 7 on the entire outer peripheral surface of the ceramic roll 1 by polishing while moving in the axial direction from one end to the other end of the ceramic roll 1. Further, simultaneously with the movement in the axial direction, the finisher device 21 vibrates (oscillates) the roller 23 and the cross hatch film 22 in the axial direction. In this way, the directional region 7 can be formed in a zigzag shape by vibrating the cross hatch film 22.

  By adjusting the shape of the cross hatch and each polishing condition described above, the shape of the directional region (length, width, repetition length, interval, etc.) can be adjusted. For example, the directional region is formed into a strip shape. It can also be formed.

  In addition, (1) You may provide the deposit | attachment removal process which removes the deposit | attachment on the roll surface prior to a rough polishing process. As this deposit removal step, a method of polishing the roll surface with a silicon film or the like can be used. Moreover, in order to finally adjust the surface roughness of the roll surface that has undergone the (3) directional region forming step, the entire polishing using a diamond film or the like may be performed again.

  In addition, the ceramic roll for papermaking processes of this invention is not limited to the said embodiment, For example, you may have a directional area | region in the outer peripheral surface whole surface. Further, the directional region may not be a zigzag shape but may be a simple band shape. Furthermore, the individual directional regions may be, for example, elliptical or the like, and a zigzag directional region may be formed entirely from these elliptical shapes. Even when the ceramic roll has a directional region as described above, the main direction of the scratches is inclined with respect to the circumferential direction. Can demonstrate its sexuality.

  As described above, the ceramic roll for papermaking process of the present invention can be suitably used in a press part or the like in the papermaking process.

DESCRIPTION OF SYMBOLS 1 Ceramic roll for papermaking processes 2 Roll main body 3 Ceramic layer 4 Roll shell 5 Head 6 Axis 7 Directional area 11 Ceramic roll for papermaking process 17 Directional area 21 Finisher device 22 Cross hatch film 23 Roller

Claims (5)

A ceramic roll for paper making process comprising a ceramic layer on the outer peripheral surface side,
Having scratches on the ceramic layer surface,
A ceramic roll for paper making process, characterized in that the main direction of the scratch eye has a directional region inclined with respect to the circumferential direction. The directional region has a strip shape with the main direction of the scratch eye as the longitudinal direction,
The ceramic roll for papermaking process according to claim 1, wherein the directional regions are arranged at regular intervals along the axial direction.   The ceramic roll for papermaking process according to claim 2, wherein the directional region is formed in a zigzag shape along a circumferential direction.   4. The ceramic roll for papermaking process according to claim 1, wherein an inclination angle with respect to a circumferential direction in a main direction of the scratch eyes is 4 ° or more and 60 ° or less. 5.   The ceramic roll for papermaking process according to any one of claims 1 to 4, wherein the arithmetic average roughness (Ra) of the outer peripheral surface is 0.2 µm or more and 2 µm or less.

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