JP5759701B2 - Absorber manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing an absorbent body.

  In the manufacture of absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads, the raw materials for absorbents (fiber materials such as defibrated pulp, superabsorbent polymer particles, etc.) that are supplied in an air stream are rotated. It has been practiced that suction is deposited in a recess formed on the outer peripheral surface of the drum, and the deposited body deposited in the recess is used as an absorbent as it is or covered with a water-permeable sheet material.

  Regarding the manufacture of the absorbent body, by providing a perforated area and a non-porous area on the bottom surface of the recess where the raw material of the absorbent body is deposited, and by varying the amount of the granular material deposited in both areas, the basis weight of the granular material is Absorbing by setting a plurality of zones on the bottom surface of the recess for depositing the absorber material (see Patent Document 1) and absorbers having a plurality of different regions, and absorbing each region. A technique (see Patent Document 2) that adjusts the amount of accumulated fibers in the body is known. Moreover, in patent document 3, a convex part is formed on the porous bottom face plate which forms the bottom face of the recessed part which deposits the raw material of an absorber, and the location corresponding to this convex part is a missing part (non-stacking part). It is described that an absorbent body is produced.

  Further, in Patent Document 4, a device including a rotating drum and an endless belt disposed below the rotating drum is used, and on a mount placed on the endless belt, continuous in the running direction of the belt. The first fiber layer is deposited and formed, and the rectangular second fiber layer is intermittently deposited and formed on the outer peripheral surface of the rotating drum, and the second fiber layer is formed on the first fiber layer. A fiber layer having a gradient of density and thickness is formed by superposing the fiber layers at a constant pitch to form a continuous polymer fiber layer having a three-dimensional shape and compressing the polymer fiber layer. A method for obtaining (absorber) is described. The second fiber layer is formed on a rectangular ventilation part provided on the outer peripheral surface of the rotating drum, and the ventilation part is a suction part that sucks the raw material of the absorber. . Therefore, the second fiber layer is a single sheet-like fiber layer in which the amount of accumulated fibers is substantially uniform.

JP 2009-232959 A JP 2004-222774 A JP 2008-206539 A JP-A-2-111365

  In the technique of Patent Document 1, the perforated region and the non-perforated region are formed on one flat support by etching or punching. Therefore, the amount of accumulated fibers changes gently at the boundary between the perforated region and the non-porous region. Also in the technique of Patent Document 2, since a plurality of areas on which different suction forces are applied are provided on a single plate, the amount of accumulated fibers gradually changes at the boundary between adjacent areas. Therefore, it is difficult to manufacture an absorber having a high-density part and a low-density part with a large density difference in the techniques of the cited documents 1 and 2.

  Moreover, in Patent Document 3, the purpose of providing a convex portion on the bottom plate is to produce an absorber having a missing portion by not depositing a raw material at a location corresponding to the convex portion as described above. . Therefore, in Patent Document 3, fibers are deposited on the convex portion or the rotating drum to produce a deposit having a plurality of regions in which the amount of accumulated fibers is different, or the density difference is large by using the deposited body. There is no description about producing an absorber having a high density part and a low density part.

In the manufacturing method described in Patent Document 4, the second fiber layer formed on the rotating drum and intermittently superimposed on the first fiber layer is sucked from the bottom surface as described above. It is formed by using a rectangular ventilation part that has only a suction part to be performed and does not have a non-suction part that does not perform suction from the bottom surface. Therefore, the shape of the second fiber layer is substantially uniform. It is limited to a rectangular shape. Patent Document 4 does not describe any shape of the second fiber layer having a non-uniform thickness or specific means for that purpose, and naturally the second fiber layer has a non-uniform thickness. There is no description about manufacturing a high-density part and a low-density part having a large density difference by using the second fiber layer of any other shape.
Not in.

  Therefore, this invention relates to the manufacturing method of the absorber which can manufacture efficiently the absorber which has a high density part and a low density part with a large density difference.

  In the present invention, the raw material of the absorber supplied on the air flow is sucked into the concave portion provided on the outer peripheral surface of the rotating drum to obtain a deposit, and on the conveying surface of the conveyor belt that runs below the rotating drum. A depositing step for obtaining a deposit by sucking into the stack, and a polymerization step for superposing the deposit obtained in the recess on the deposit obtained on the conveying surface of the conveyor belt to obtain a polymerized deposit, A pressing step for pressurizing and compressing the polymer deposit, and in the deposition step, a bottom surface is formed of a porous plate and a suction portion that performs suction from the bottom surface and the bottom surface is non-breathable, and from the bottom surface. The raw material is deposited in the recesses, each having a plurality of non-suction portions that do not perform suction, and in the pressing step, the polymerization deposit is pressurized to have high-density portions and low-density portions having different densities. Absorber to obtain absorber There is provided a manufacturing method.

  According to the method for producing an absorbent body of the present invention, an absorbent body having a high density part and a low density part having a large density difference can be produced efficiently.

FIG. 1 is a schematic diagram showing an example of an absorbent body manufacturing apparatus that can be used in the implementation of the absorbent body manufacturing method of the present invention. FIG. 2 is a schematic diagram of a main part of the apparatus shown in FIG. 3 is an exploded perspective view of the outer peripheral portion of the rotating drum in the apparatus shown in FIG. 4 is a view showing a part of the outer peripheral portion of the rotating drum in the apparatus shown in FIG. 1, FIG. 4 (a) is a developed view of the outer peripheral portion, and FIG. 4 (b) is a view of FIG. It is the II sectional view taken on the line of). FIG. 5 is a cross-sectional view (corresponding to FIG. 4 (b)) showing a cross-section of a recess in which a fiber material is deposited. FIG. 6A is a perspective view showing a polymer deposit obtained in the present invention, and FIG. 6B is a cross-sectional view taken along the line II-II of the polymer deposit. Fig.7 (a) is a perspective view which shows an example of the absorber obtained by press-compressing the deposit body shown in FIG. 6, FIG.7 (b) is the III-III sectional view taken on the line of this absorber. is there. FIG. 8A is an explanatory view for explaining the diffusion direction controllability of one absorber obtained by the present invention, and FIG. 8B shows the case of a conventional absorber that does not have the diffusion direction controllability. FIG. FIG. 9 is a view showing another embodiment of the present invention, FIG. 9 (a) is a perspective view showing a recess and its periphery in the embodiment, and FIG. 9 (b) is obtained using the recess. FIG. 9C is a cross-sectional view showing a cross-section in the width direction at the center in the longitudinal direction of the superposition portion, and FIG. 9D is a cross-sectional view showing the superposition portion of the obtained polymer deposit. FIG. 9E is a sectional view showing a cross section in the width direction at the center in the longitudinal direction of the absorber. FIG. 10 is a view showing still another embodiment of the present invention, FIG. 10 (a) is a perspective view showing a recess and its periphery in the embodiment, and FIG. 10 (b) is a view using the recess. FIG. 10C is a cross-sectional view showing a cross-section in the width direction at the center in the longitudinal direction of the superposition portion, and FIG. 10D is a cross-sectional view showing the superposition portion of the obtained polymer deposit. The perspective view which shows the absorber obtained by compressing and compressing the superposition | polymerization part to show, FIG.10 (e) is sectional drawing which shows the width direction cross section in the longitudinal direction center of the absorber. FIG. 11 is a front view showing another example of the flattening roll in the apparatus shown in FIG.

  Hereinafter, the present invention will be described based on a preferred embodiment thereof with reference to the drawings. FIG.1 and FIG.2 shows an example of the manufacturing apparatus which can be used for implementation of the manufacturing method of the absorber of this invention. The absorbent body manufacturing apparatus 1 shown in FIGS. 1 and 2 includes a rotary drum 2 that is rotationally driven in an arrow direction R2, a vacuum conveyor 4 that includes a conveyor belt 43 that travels below the rotary drum 2, and a rotary drum 2 Duct 5 for supplying the fiber material 30 as the raw material of the absorber to the outer peripheral surface 21 and the conveying surface 43a of the conveyor belt 43, the fiber material supply unit 6 for supplying the fiber material 30 to the duct 5, and the pressing device 7; The cutting device 8 is provided.

  As shown in FIGS. 1 and 2, the rotary drum 2 has a cylindrical shape, and a member (pattern forming plate 27 described later) that forms the outer peripheral surface 21 by receiving power from a motor such as a motor is around a horizontal axis. Rotate. The drum main body (a frame body 25 and a porous plate 26 described later) positioned inside the member forming the outer peripheral surface 21 is fixed and does not rotate. As shown in FIG. 4, the rotary drum 2 has a plurality of recesses 22 on the outer peripheral surface 21 for depositing a fiber material 30 as a raw material for the absorber. A plurality of recesses 22 of the rotating drum 2 are formed at predetermined intervals in the circumferential direction (2X direction) of the rotating drum 2. In FIG. 4, the 2X direction is the circumferential direction of the rotating drum 2, and the 2Y direction is the width direction of the rotating drum 2 (a direction parallel to the rotation axis of the rotating drum 2).

  As shown in FIGS. 3 and 4, the rotary drum 2 includes a cylindrical frame body 25 made of a metal rigid body, a porous plate 26 fixed on the outer surface side of the frame body 25, and a porous plate. 26 has a pattern forming plate 27 fixed on the outer surface side of 26. As shown in FIG. 3, the rotating drum 2 has four pattern forming plates 27, and each pattern forming plate 27 is arranged at a certain interval in the circumferential direction (2X direction) of the rotating drum 2. Has been. As a fixing means for the porous plate 26 and the pattern forming plate 27, various known fixing methods such as bolts and adhesives can be used without particular limitation.

  A communication hole (not shown) that penetrates the portion in the thickness direction is formed in a portion corresponding to the concave portion 22 in the outer surface portion of the frame body 25. The porous plate 26 has a large number of pores, and can transmit only air without transmitting the fiber material 30 as the raw material of the absorber supplied on the air flow. As the porous plate 26, those conventionally used in this type of fiber stacking apparatus can be used without particular limitation. For example, a metal or resin mesh plate or a metal or resin plate can be etched or punched. What formed many pores etc. can be used. The pattern forming plate 27 has an outer surface 27a that forms the outer peripheral surface 21 of the rotating drum 2 and an inner surface 27b that faces the rotating shaft side of the rotating drum 2. The pattern forming plate 27 is disposed between the outer surface 27a and the inner surface 27b. The space has a shape corresponding to the three-dimensional shape.

  As shown in FIG. 4B, the recess 22 has a bottom surface 23a made of a porous plate 26, and suction is performed from the bottom surface 23a while the recess 22 passes over a space B described later. And a non-suction part 24 in which suction from the bottom surface 24a is not performed even when the recess 22 passes over the space B described later. Yes. More specifically, as shown in FIG. 4A, the suction part 23 and the non-suction part 24 are each formed in a long shape in the circumferential direction (2X) of the rotating drum. A plurality of non-suction portions 24 are provided. The suction part 23 and the non-suction part 24 are alternately formed in the width direction (2Y) of the rotary drum. Further, as shown in FIG. 4B, the bottom surface 24a of the non-suction portion 24 is made of a non-breathable member 28 disposed on the porous plate 26, and suction from the bottom surface 24a is not performed.

  In the present embodiment, the depth of the concave portion 22 from the outer peripheral surface 21 of the rotary drum 2 is different between the suction portion 23 and the non-suction portion 24. That is, the depth d1 of the suction part 23 is the same as the thickness of the pattern formation plate 27 as shown in FIG. 4B, whereas the depth d2 of the non-suction part 24 is the pattern formation plate 27. The thickness (d1-t) is obtained by subtracting the thickness t of the non-breathable member 28 from the thickness of the air. The depth d1 of the suction part 23 and the depth d2 of the non-suction part 24 are the distances from the outer peripheral surface 21 of the rotary drum 2 to the bottom surfaces 23a and 24a of the parts 23 and 24, and the rotation axis (center line) of the rotary drum 2. Measure along a straight line perpendicular to. The thickness t of the non-breathable member 28 is measured in the same manner.

  Thus, the suction part 23 and the non-suction part 24 provided with the non-breathable member 28 are provided in the concave part 22 in which the fiber material as the raw material of the absorber is deposited, and the depth d2 of the non-suction part 24 is suctioned. By making the depth smaller than the depth d1 of the portion 23, the fiber material is deposited on both the suction portion 23 and the non-suction portion 24, while the amount of the fiber material deposited on the suction portion 23 and the amount deposited on the non-suction portion 24. It is easy to provide a large difference between

  Note that the depth d2 of the non-suction portion 24 may be zero. That is, the thickness t of the non-breathable member 28 constituting the non-suction part 24 is made the same as the thickness of the pattern forming plate 27, and the bottom surface 24 a of the non-suction part 24 forms the outer peripheral surface 21 of the rotary drum 2. The outer surface 27a of the forming plate 27 may be formed to be flush with the outer surface 27a. When the depth d2 of the non-suction part 24 is zero, the fiber material is not deposited on the non-suction part 24 in the deposition process described later. The deposited body does not have a portion corresponding to the portion 24 (a portion 34 to be described later) and has only a plurality of portions corresponding to the suction portion 23 (a portion 33 to be described later).

  In the example shown in FIGS. 3 and 4, the non-breathable member 28 for forming the non-suction portion 24 constitutes a part of the pattern forming plate 27. More specifically, the non-breathable member 28 having a rectangular cross section is integrally formed so as to form a surface flush with the inner surface 27b of the pattern forming plate 27 made of synthetic resin. In the present embodiment, the non-breathable member 28 is formed on the porous plate 26 by fixing the pattern forming plate 27 integrated with the non-breathable member 28 on the frame body 25 and / or the porous plate 26. However, the lower surface of the air-impermeable member 28 may be directly fixed on the porous plate 26.

  Spaces B, C, and D that are partitioned from each other are formed in the drum main body located on the inner side (rotating shaft side) of the rotating drum 2. A known exhaust device (not shown) such as an intake fan is connected to the space B, and the interior of the space B can be maintained at a negative pressure by operating the exhaust device. As described above, the drum body (the frame body 25 and the porous plate 26) is fixed, and even if the pattern forming plate 27 that forms the outer peripheral surface 21 of the rotating drum 2 rotates, the spaces B, C, and D The position does not change. While the individual recesses 22 pass over the space B maintained at a negative pressure, the pores of the porous plate 26 forming the bottom surface 23a of each recess 22 function as suction holes. The rotating drum 2 has one end in the axial direction of the rotating shaft sealed with a plate that rotates integrally with the rotating drum 2, and the other end sealed airtight with a plate that does not rotate. The spaces B to D are partitioned by a plate provided from the rotating shaft side of the rotating drum 2 toward the inner surface of the rotating drum 2.

  As shown in FIG. 2, the vacuum conveyor 4 is disposed at a position facing the rotating drum 2 with the endless breathable conveyor belt 43 spanned between the drive roll 41 and the driven roll 42 and the conveyor belt 43 interposed therebetween. The vacuum box 44 is provided. The conveyor belt 43 is a belt-shaped breathable belt having a mesh connected endlessly, and is continuously guided along rolls 41 and 42 to move along a predetermined path. The conveying surface 43a of the conveyor belt 43 on which the fiber material is supplied and a deposit is formed is substantially flat. The vacuum box 44 has a box-like shape having upper and lower surfaces, left and right side surfaces, and a rear surface, and has an opening (not shown) that opens upward (in the direction of the rotating drum 2) on the upper surface. ing. The vacuum box 44 extends from below (directly below) the rotating drum 2 in the direction indicated by A in the drawing (the traveling direction of the conveyor belt 43) and in the direction opposite to the direction A. A known exhaust device (not shown) such as an intake fan is connected to the vacuum box 44 via an exhaust pipe (not shown), and the inside of the vacuum box 44 is maintained at a negative pressure by the operation of the exhaust device. Is possible.

  As shown in FIGS. 1 and 2, the duct 5 includes a part of the outer peripheral surface 21 of the rotating drum 2 (a part located on the space B) and a part of the conveying surface 43 a of the conveyor belt 43 (on the rotating drum 2. On the other hand, one end 51 that covers a portion of the conveyor belt 43 that is located upstream in the traveling direction A) and the other end 52 that is connected to the fiber material supply unit 6 and functions as a supply port for the raw material (fiber material) of the absorbent body. The outer peripheral surface 21 of the rotating drum 2 and the conveyor surface of the conveyor belt 43 are sucked into the duct 5 by suction from the bottom surface 23a of the recess 22 located on the space B and the conveyor surface 43a of the conveyor belt 43. An air flow that flows toward 43a is generated.

  In the duct 5, as a supply path for the raw material (fiber material) of the absorbent body, a conveyor path extends from the other end 52 (raw material supply port) to the outer peripheral surface 21 of the rotary drum 2 and the other end 52. The supply path 5 </ b> B toward the transport surface 43 a of 43 is provided independently of each other. More specifically, in the duct 5, as shown in FIGS. 1 and 2, from the vicinity of the fiber material supply unit 6 disposed on the other end 52 side to the vicinity of the outer peripheral surface 21 of the rotary drum 2. A flat partition wall 53 is provided that extends obliquely downward and extends over the entire width of the duct 5 (the entire length in the width direction 2Y of the rotary drum 2). By the partition wall 53, the inside of the duct 5 is divided into an upper layer and a lower layer. It is separated. The upper layer is the supply path 5A, and the lower layer is the supply path 5B. The partition wall 53 is made of synthetic resin or metal and is a non-breathable member.

  The fiber material supply unit 6 includes a defibrating device 61, which introduces sheet-shaped raw materials (not shown) such as pulp sheets into the defibrating device 61, and supplies the defibrated fiber material 30 to the supply path in the duct 5. It is configured to supply to 5A and 5B, respectively. In the middle of the duct 5, a water-absorbing polymer introduction part that introduces water-absorbing polymer particles into the supply paths 5 </ b> A and 5 </ b> B can also be provided.

  In the duct 5, as shown in FIG. 2, a flattening roll 55 is provided for flattening the surface 32 a of the deposit 32 deposited on the transport surface 43 a of the conveyor belt 43. The flattening roll 55 is arranged on the upstream side of the conveying direction (traveling direction of the conveyor belt 43) A of the deposit 32 with respect to the rotating drum 2 and above the conveyor belt 43, and has a cylindrical shape with a smooth outer peripheral surface. And receives power from a motor such as a motor to rotate around the horizontal axis in the direction of arrow R5. A predetermined gap is formed between the outer peripheral surface of the flattening roll 55 and the conveying surface 43 a of the conveyor belt 43. By adjusting this gap, it is possible to adjust the thickness of the deposit 32 immediately before the polymerization step described later. The outer diameter of the flattening roll 55 is smaller than that of the rotary drum 2, and the length of the flattening roll 55 in the width direction (the length in the direction orthogonal to the transport direction A) is flattened by the flattening roll 55. It is longer than the length in the width direction of the deposited body 32 (the length in the direction orthogonal to the transport direction A), and the outer peripheral surface of the flattening roll 55 can be brought into contact with the entire surface 32 a of the deposited body 32.

  As the flattening roll 55 rotates in the direction indicated by the arrow R5, the smooth outer peripheral surface of the flattening roll 55 comes into contact with the surface 32a of the deposit 32 having the unevenness, thereby smoothing the unevenness. The surface 32a becomes flat. On the surface 32a thus flattened, the deposit 31 obtained in the recess 22 of the rotary drum 2 is superposed in the polymerization step described later. In this way, by making the surface 32a on which the other accumulation body 31 is superimposed in the accumulation body 32 on the conveying surface 43a of the conveyor belt 43 flattened before the other accumulation body 31 is overlaid, Even if the shape of the stacked body 31 is complicated, it is possible to stably transfer.

  The press apparatus 7 includes a pair of rolls 71 and 72 having a smooth surface, and is configured to pressurize an object to be pressed introduced between the rolls 71 and 72 from the upper and lower surfaces and compress in the thickness direction. As the pressing device 7, instead of the one provided with a pair of rolls 71, 72 having a smooth surface, one provided with a pair of embossing rolls in which convex portions for embossing are formed on the peripheral surface of one or both rolls. It is also preferable to use it from the point that a low density part and a high density part by embossing can be formed on the absorber to improve the absorption performance.

  As the cutting device 8, in the manufacture of sanitary napkins and absorbent articles, those conventionally used for cutting the absorbent continuous body can be used without particular limitation. The cutting device 8 shown in FIG. 1 includes a cutter roll 82 having a cutting blade 81 on its peripheral surface, and an anvil roll 83 having a smooth peripheral surface for receiving the cutting blade.

  Next, an embodiment of a method for continuously producing the absorbent body 3 using the absorbent body production apparatus 1 described above, that is, an embodiment of the absorbent body production method of the present invention will be described. In order to manufacture the absorber 3 using the absorber manufacturing apparatus 1, the exhaust device connected to each of the space B in the rotary drum 2 and the vacuum box 44 is operated to make negative pressure. By mainly setting the negative pressure in the space B, an air flow is generated in the supply path 5A in the duct 5 to convey the raw material of the absorber to the outer peripheral surface 21 of the rotary drum 2, and mainly in the vacuum box 44. By setting the negative pressure, an air flow that conveys the raw material to the conveying surface 43 a of the conveyor belt 43 is generated in the supply path 5 </ b> B in the duct 5. Further, the rotating drum 2 is rotated in the direction R2, and the conveyor belt 43 is caused to travel in the direction A.

  When the fiber material supply unit 6 is operated to supply the fiber material 30 into the duct 5 from the other end 52 (supply port) of the duct 5, a part of the fiber material 30 is supplied to the supply path 5 </ b> A in the duct 5. The air material flows in the air and flows in a scattered state and is supplied toward the outer peripheral surface 21 of the rotary drum 2, and the remainder of the fiber material 30 rides in the air flow flowing in the supply path 5B in the duct 5 and is scattered. Is supplied toward the conveying surface 43a of the conveyor belt 43.

  As shown in FIG. 5, the fiber material 30 conveyed in the supply path 5 </ b> A is sucked and accumulated in the recess 22 of the rotary drum 2. In this embodiment, as shown in FIG. 5, the fiber material 30 is deposited not only on the suction portion 23 where suction is performed from the bottom surface 23 a but also on the non-suction portion 24 where suction is not performed from the bottom surface 24 a. Preferably, as shown in FIG. 5, the fiber material 30 is deposited so that the upper surface 31 a of the deposit 31 deposited in the recess 22 is flat. Further, as shown in FIG. 5, it is preferable to deposit so that the position of the upper surface 31 a of the deposited body 31 deposited in both the suction part 23 and the non-suction part 24 substantially coincides with the position of the outer peripheral surface 21. In addition, after depositing an excessive amount of fiber material 30 exceeding the position of the outer peripheral surface 21 on the suction portion 23 and / or the non-suction portion 24, the excess amount of the fiber material 30 may be removed with a scuffing roll or the like. good.

  In order to deposit a desired amount of the fiber material 30 on the non-suction part 24 or to deposit the fiber material 30 in the above-described preferred state, the entanglement with the fiber material 30 sucked on the bottom surface 23a of the suction part 23 A desired amount of the fiber material 30 is deposited also on the non-suction portion 24 due to the influence of the air flow sucked into the bottom surface 23a. For example, the width W2 of the non-suction part 24, the ratio (W1 / W2) of the width of the non-suction part W2 to the width W1 of the suction part 23 is adjusted, or the width W2, the ratio (W1 / W2), etc. Thus, the suction force generated on the bottom surface 23a of the suction part 23 and the ratio (d2 / d1) of the depth d2 of the non-suction part 24 to the depth d1 of the suction part 23 are adjusted.

  From the viewpoint of releasing the deposit 31 from the recess 22 and maintaining the shape of the deposit 31 after release (particularly the portion 33 corresponding to the suction portion 23) until the pressing step, the width W1 of the suction portion 23 is 3 to 30 mm, and more preferably 5 to 20 mm. In addition, from the viewpoint that the fiber material can be sufficiently deposited up to substantially the same height as the outer peripheral surface 21, the width W2 of the non-suction portion 24 is preferably 3 to 30 mm, and more preferably 5 to 20 mm. The ratio (W1 / W2) of the width W1 of the suction part 23 and the width W2 of the non-suction part 24 is preferably 0.1 to 10, more preferably 0.2 to 5.

  Further, from the viewpoint of releasing the deposit 31 from the recess 22 and maintaining the shape of the deposit 31 after release (particularly, the portion 33 corresponding to the suction portion 23) until the pressing step, the depth of the suction portion 23 is increased. The length d1 is preferably 1 to 30 mm, particularly preferably 3 to 20 mm, and more preferably 5 to 10 mm. Further, the ratio (d2 / d1) of the depth d2 of the non-suction part 24 to the depth d1 of the suction part 23 is preferably 0.05 to 0.95, more preferably 0.5 to 0.9. It is. Moreover, it is preferable that ratio (width W2 / depth d2) of the width | variety W2 and the depth d2 of the non-attraction | suction part 24 is 0.1-10, More preferably, it is 0.2-5.

  On the other hand, as shown in FIG. 2, the fiber material 30 conveyed in the supply path 5B is sucked by the conveying surface 43a of the conveyor belt 43 and deposited on the core wrap sheet 37 disposed on the conveying surface 4a. Then, a belt-like deposit 32 that is continuous in the running direction A of the conveyor belt 43 is formed. In the present embodiment, as shown in FIG. 1, a strip-shaped core wrap sheet 37 made of tissue paper or a liquid-permeable nonwoven fabric or the like is formed on the transport surface 43 a of the conveyor belt 43 before the deposit 32 is formed. Introduced, a band-like deposit 32 is formed on the core wrap sheet 37.

  The belt-shaped deposit 32 is conveyed by the conveyor belt 43 downward (directly below) of the rotating drum 2, and the surface 32 a of the belt-shaped deposit 32 is disposed by the flattening roll 55 disposed upstream of the rotating drum 2 in the conveying direction A. Flattened.

  In the subsequent polymerization step, the deposits 31 and 32 obtained through the above-described deposition step are overlapped with each other to form a polymerization deposit 39. That is, the deposit 31 deposited in the recess 22 of the rotary drum 2 in the supply path 5A in the duct 5 is still deposited in the recess 22 by further rotation of the rotary drum 2 in the direction R2. It is transported to a position facing the upper deposit 32 (the lowest point position of the rotary drum 2), and at the position opposed to the surface 32a of the deposit 32 by suction and its own weight from the vacuum box 44. And the mold is released from the recess 22. In this way, the plurality of deposits 31 formed by the plurality of recesses 22 of the rotating drum 2 are intermittently superposed on the surface 32a of the strip-like deposit 32 at a constant pitch, and the plurality of deposits 31 and the strips are formed. A two-layered belt-like polymerized deposit 39 composed of the deposit 32 is formed.

  In this embodiment, as shown in FIGS. 1 and 2, the belt-like polymerized deposit 39 is formed on the core wrap sheet 37 introduced on the conveying surface 43 a of the conveyor belt 43. After the above-described polymerization process is performed, both side portions of the core wrap sheet 37 are folded downstream of the rotating drum 2 in the transport direction A, and the upper and lower surfaces of the polymerization deposit 39 are covered with the core wrap sheet 37. And the superposition | polymerization deposit 39 of the state coat | covered with the core wrap sheet | seat 37 is introduce | transduced between a pair of rolls 71 and 72 of the press apparatus 7, and is compressed to the thickness direction, and a press process is implemented.

  FIG. 6 shows a strip-shaped polymer deposit 39 immediately after the polymerization process (before the pressing process). As shown in FIG. 6, the polymerized deposit 39 before being pressed by the press device 7 does not overlap the polymerized portion 38 </ b> A in which the deposit 31 is superimposed on the deposit 32 (the deposit 31). 32) (non-polymerized portions 38B), and the polymerized portions 38A and the non-polymerized portions 38B are alternately arranged in the length direction (conveying direction A) of the polymer deposit 39. In the overlapping portion 38A, the portion 33 corresponding to the suction portion 23 is thick, and the portion 34 corresponding to the non-suction portion 24 is thin. In addition, one surface (a surface facing the conveyor belt 43) 39a of the polymerization deposit 39 is substantially flat, while the other surface 39b is an uneven surface having a large undulation in the overlapping portion 38A. The other surface 39b is substantially flat in the non-polymerized portion 38B by the flattening process by the flattening roll 55 described above. As shown in FIG. 6, a convex portion and a groove portion are formed on the uneven surface 39 b in the overlapping portion 38 </ b> A so as to extend in a direction (3X direction) corresponding to the circumferential direction of the rotary drum 2. As shown in FIG. 6B, the convex portion is a portion 33 corresponding to the suction portion 23, and the groove portion is a portion 34 corresponding to the non-suction portion 24.

  In the present embodiment, the polymer deposit 39 having such a form is pressurized by the press device 7 to actively reduce the thickness of the portion 33 corresponding to the suction portion 23. As a result, the thickness difference and / or the thickness ratio between the two portions 33 is reduced, so that the portion 33 corresponding to the suction portion 23 becomes the high density portion 35 and the portion 34 corresponding to the non-suction portion 24 becomes the low density portion 36. Thus, the band-shaped absorber 3 shown in FIG. 7 is obtained. In the absorbent body 3 obtained in this embodiment, as shown in FIG. 7, the high-density part 35 and the low-density part 36 extend in a direction (3X direction) corresponding to the circumferential direction of the rotary drum 2. Is formed. The pressure compression by the press device 7 may be performed by heating one or both of the rolls 71 and 72, or may not be performed. When heating and compressing under pressure, it is preferable to pressurize and compress one or both of the rolls 71 and 72 to about 100 ° C.

  After the pressing process by the pressing device 7, the strip-shaped absorbent body 3 is cut by the non-polymerized portion 38B by the cutting device 8 while being covered with the core wrap sheet 37 as shown in FIG. It is the length of one article.

  According to the manufacturing method of the absorber of this embodiment, the absorber 3 having the high density part 35 and the low density part 36 having a large density difference can be efficiently manufactured in this way. The manufacturing method of the absorber according to the present embodiment does not require the introduction of a new large-scale facility or the significant modification of the existing facility, and can efficiently manufacture the absorber 3 using the existing facility. .

  The absorber 3 preferably has substantially the same thickness at the high density portion 35 and the low density portion 36. The thickness of the absorber 3 is substantially the same in the high-density part 35 and the low-density part 36. The thickness T5 of the high-density part 35 and the thickness of the low-density part 36 measured by the following [Measurement of thickness of measurement piece] It means that the ratio to T6 (T5 / T6) is 1.2 or less. From the viewpoint of increasing the density difference between the high-density part 35 and the low-density part 36 so that the diffusion direction control ability described later can be efficiently expressed, or incorporating the absorbent body 3 into an absorbent article such as a sanitary napkin or a disposable diaper. The ratio (T5 / T6) is preferably 1.0 to 1.2, more preferably 1.0, from the viewpoint of preventing the wearer of the absorbent article from feeling uncomfortable at this time. -1.1.

[Measurement of measurement piece thickness]
The thickness of the entire measurement piece including the high density portion and the low density portion is measured. The thickness measurement conforms to JIS-P8118: 1998. However, for the measurement, a peacock precision measuring instrument (model R1-C), which is a micrometer having two parallel pressure surfaces (a fixed pressure surface and a movable pressure surface), is used, and the diameter of the probe movable pressure surface is 5 mm. The pressure was measured at 2.0 N or less. The size of the test specimen for measurement is not less than the size of the following plate. A 20 mm × 20 mm plate (weight 5.4 g) is placed on the test piece, the measuring element movable pressurizing surface is operated at a speed of 3 mm / s or less, applied to the plate, and the value immediately after stabilization is read. The pressure between the pressing surfaces (pressure applied to the test piece) is 2 kPa or less.

According to the manufacturing method of the absorber of this embodiment, the absorber which has the high density part 35 and the low density part 36 with a large density difference can be manufactured easily. It is also easy to manufacture an absorbent body with a clear density difference at the boundary between the high density portion 35 and the low density portion 36. Absorbent body to be manufactured in the present invention are, for example, the basis weight of the low density portion 36, 50 to 300 g / cm ^2, particularly preferably from 100 to 200 g / cm ^2, density and low-density portion of the high density portion 35 The ratio to the density of 36 (the former / the latter) is preferably 1.1 to 5.0, particularly preferably 1.5 to 3.0. The preferred width (width in the 3Y direction) of the high density portion 35 and the low density portion 36 and the ratio of the width are the same as the preferred width and ratio of the suction portion 23 and the non-suction portion 24 described above. The density of the high density part and the low density part is measured as follows.

[Measurement of the density of the high density part and low density part]
The density of the high density part 35 and the low density part 36 is measured according to JIS-P8118: 1998. Specifically, D (density: g / cm ³ ) = W (basis weight: g / m ² ) / T (thickness: mm) is calculated. The basis weight is described in JIS-P8124, the test piece is cut with a cutter or a cutter, and the weight is measured with a scale. Divide the measured weight by the area to calculate the basis weight. The thickness is [Measurement of thickness of measurement piece], and the thickness of the entire measurement piece including the high density portion and the low density portion is measured. In the basis weight measurement of the present application, the high density part and the low density part are cut into a certain area according to the processing dimensions, respectively, and the weight is measured to calculate the basis weight.

  The preferable absorbent body 3 produced in the present invention has the high density part 35 and the low density part 36 having a large density difference, so that the diffusion direction control ability is efficiently expressed as shown in FIG. That is, liquids such as menstrual blood and urine supplied onto the absorber 3 diffuse well in the direction in which the low density portion 36 extends, while diffusion in the direction orthogonal to the direction in which the low density portion 36 extends is suppressed. The The liquid diffused along the low density portion 36 is reliably absorbed and held in the adjacent high density portion 35 in each portion. Therefore, effective use of the absorption capacity of the absorber in the direction in which the low density portion 36 extends while suppressing liquid diffusion in the direction intersecting the low density portion 36 to prevent liquid leakage from both ends of the direction. Can be achieved.

  For example, when the absorbent body shown in FIG. 8A is incorporated into an absorbent article such as a sanitary napkin or a disposable diaper, the direction in which the high density portion 35 and the low density portion 36 extend coincides with the wearer's front-rear direction. By doing so, it is possible to obtain an absorbent article that has excellent leakage prevention performance and can effectively utilize the absorption capacity of the absorber. In the absorbent body manufactured according to the present invention, the high density part 35 and the low density part 36 may extend in the width direction of the absorbent body (direction orthogonal to the 3X direction). Such an absorbent body is arranged from the front-rear direction of the absorbent article by arranging regions having alternating high-density portions 35 and low-density portions 36 in the front end and / or rear end vicinity of the wearer front-rear direction. An absorbent article having excellent liquid leakage prevention properties can be obtained.

  FIG. 8B shows a liquid diffusion state when the same amount of liquid as that shown in FIG. 8A is supplied to a conventional absorber having the same density in the entire region. In such an absorber, since the liquid diffuses to the same extent in all directions, the liquid easily reaches both ends in the width direction with a small size, so that the liquid easily leaks from both ends.

  Hereinafter, another embodiment of the present invention will be described with reference to FIGS. Regarding other embodiments described later, constituent parts different from the above-described embodiments are mainly described, and the same constituent parts are denoted by the same reference numerals and description thereof is omitted. For the components not specifically described, the description of the above-described embodiment is applied as appropriate.

  Fig.9 (a) is a perspective view which shows the recessed part 22A in the other embodiment of this invention. The inside of the recess 22A is divided into a plurality of areas by a non-suction part 24 extending in the circumferential direction (2X in FIG. 4) and the width direction (2Y in FIG. 4) of the rotating drum. It has become. More specifically, the recess 22A is formed by disposing a partition member 9A having a height that does not reach the outer peripheral surface 21 of the rotary drum in a space having an oval cross section formed by the pattern forming plate 27A. The partition member 9A includes a plurality of first partition walls 91 extending in the circumferential direction of the rotary drum 2 and the width direction of the rotary drum 2, and extends between the first partition walls 91 or between the first partition walls 91 and the pattern forming plate 27A. It consists of the 2nd partition wall 92 which connects between the inner peripheral surfaces. The partition member 9A is made of synthetic resin or metal and is a non-breathable member. By this partition member 9A, a large number of suction portions 23 in which the bottom surface is made of a porous plate (not shown) in the recess 22A and suction is performed from the bottom surface, and the bottom surface is composed of the upper end of the partition member 9A, from the bottom surface And a non-suction portion 24 where no suction is performed.

  9 (b) and 9 (c), a polymerization portion 38A1 (a portion where two deposits are overlapped) in the band-shaped polymer deposit 39A obtained using the recess 22A and according to the embodiment described above. It is shown. The superposition part 38A1 was formed on the transport surface 43a of the conveyor belt 43 and a deposit (not shown) obtained by depositing a fiber material (such as defibrated pulp) as a raw material of the absorber in the recess 22A. It is obtained by polymerizing the deposit 32. The overlapping portion 38A1 has one surface that is flat, while the other surface is an uneven surface on which a large number of block-shaped protrusions 39A 'are formed. The superposition part 38A1 is pressed by a pressing device and compressed in the thickness direction, whereby the high density part 35 and the low density part 36 are arranged as shown in FIGS. 9 (d) and 9 (e). 3A is obtained.

  FIG. 10A is a perspective view showing a recess 22B in still another embodiment. The recess 22B is formed by disposing a partition member 9B inside a space having an oval cross section formed by the pattern forming plate 27A. The partition member 9B has first and second partition walls 91 and 92 having a height that reaches the outer peripheral surface 21 of the rotary drum 2 on the front and rear sides and the left and right sides in the rotation direction R2 of the rotary drum 2, and rotates at the center. Three non-breathable members 83 having a height that does not reach the outer peripheral surface 21 of the drum 2 are provided. By this partition member 9B, a plurality of suction portions 23 having a bottom surface made of a porous plate (not shown) and suctioned from the bottom surface and a bottom surface having a non-breathable member 83 are formed in the central portion of the recess 22B. In addition, a non-suction portion 24 that is not sucked from the bottom surface is formed.

  10 (b) and 10 (c), the overlapping portion 38A2 (a portion where the two deposits are overlapped) in the band-shaped polymer deposit 39B obtained using the recess 22B and according to the embodiment described above. It is shown. The overlapping portion 38A2 has a central deposit 39B ′ having a flat surface on one side and an uneven surface on the other side, and is separated from the central deposit 39B ′ around the central deposit 39B ′. It has a plurality of outer peripheral deposits 39B ″. By pressing this overlapping portion 38A2 with a press device and compressing it in the thickness direction, a high-density portion 35 and a low-density portion 36 are formed in the central portion. The absorber 3B arranged as shown in (d) and FIG. 10 (e) is obtained.

  As the fiber material as the raw material of the absorbent body, various materials conventionally used for absorbent bodies of absorbent articles such as sanitary napkins, panty liners, and disposable diapers can be used without particular limitation. For example, pulp fibers such as defibrated pulp, short fibers of cellulosic fibers such as rayon fibers and cotton fibers, and short fibers of synthetic fibers such as polyethylene are used. These fibers can be used alone or in combination of two or more. Moreover, as a raw material of the absorber 3, a water-absorbing polymer may be introduced into the duct 5 together with the fiber material, and further, a deodorant, an antibacterial agent, and the like are supplied as necessary together with the fiber material. You can also.

  As mentioned above, although several embodiment of the manufacturing method of the absorber of this invention was described, this invention is not restrict | limited to embodiment mentioned above, Each can be changed suitably. For example, instead of the flattening roll 55 (see FIG. 2) having a smooth peripheral surface, a flattening roll 56 having a large number of protrusions on the peripheral surface can be used as shown in FIG. The flattening roll 56 includes a cylindrical roll main body 56A and a large number of scraping protrusions 56B provided upright on the outer peripheral surface of the roll main body 56A. The surface 32a of the deposit 32 on the conveyor belt 43 is leveled and flattened at the tip of the belt. The protrusion 56B can be constituted by a brush, for example. Further, there may be no flattening roll.

  In addition, the suction part 23 and the non-suction part 24 are each formed in a band shape, and the suction part 23 and the non-suction part 24 extend in the width direction 2Y of the rotary drum 2 (the rotational axis direction of the rotary drum 2). It may be a thing. Moreover, the number of each of the suction part 23 and the non-suction part 24 formed in a belt shape can be 2 to 10, for example. The number of the suction part 23 and the non-suction part 24 may be the same or different.

  Further, the absorbent body produced in the present invention is not limited to the one whose upper and lower surfaces are covered with a single core wrap sheet, and whose upper and lower surfaces are covered with two separate core wrap sheets. Alternatively, the upper and lower surfaces may not be covered with the core wrap sheet. Further, the absorbent body produced according to the present invention has a region in which strip-like high-density portions and low-density portions are arranged in stripes at the center in the longitudinal direction or at the front or rear in the longitudinal direction, and the front of the region. In addition, an absorber separated from the region may be provided on the rear side. In addition, a band-shaped high-density part and a low-density part are arranged in stripes at the center in the width direction, and an absorber separated from the area is provided on one or both sides of the area. It may be.

  The absorbent body produced in the present invention is preferably used as an absorbent body for absorbent articles. Absorbent articles are used mainly to absorb and retain body fluids excreted from the body such as urine and menstrual blood. Absorbent articles include, for example, disposable diapers, sanitary napkins, incontinence pads, panty liners, etc., but are not limited to these, and widely include articles used to absorb liquid discharged from the human body. To do.

  The absorbent article typically includes a top sheet, a back sheet, and a liquid-retaining absorbent body disposed between both sheets. The upper and lower surfaces of the absorber may be covered with one or a plurality of core wrap sheets. The back sheet may or may not have water vapor permeability. The absorbent article may further include various members according to specific uses of the absorbent article. Such members are known to those skilled in the art. For example, when the absorbent article is applied to a disposable diaper or a sanitary napkin, a pair or two or more pairs of three-dimensional guards can be disposed on the outer side of both side portions where the absorbent body stands.

  The description omitted in one embodiment described above and the requirements of only one embodiment can be applied to other embodiments as appropriate, and the requirements in each embodiment can be appropriately interchanged between the embodiments. Can be substituted.

DESCRIPTION OF SYMBOLS 1 Absorbent body manufacturing apparatus 2 Rotating drum 21 Outer peripheral surface 22, 22A, 22B of rotating drum Recess 23 Suction part 24 Non-suction part 28 Non-breathable member 3, 3A, 3B Absorber 30 Fiber material (raw material of absorber)
31, 32 Deposits 35 High-density part 36 Low-density part 37 Core wrap sheets 38A, 38A1, 38A2 Superposition part 38B Non-polymerization part 39, 39A, 39B Superposition deposit 4 Vacuum conveyor 43 Conveyor belt 43a Conveyor belt conveyance surface 44 Vacuum Box 5 Duct 53 Partitions 55 and 56 Flattening roll 6 Fiber material supply unit 7 Press device 8 Cutting device

Claims (7)

The absorbent material supplied in the air flow is sucked into the concave portion provided on the outer peripheral surface of the rotating drum to obtain a deposit, and sucked onto the conveying surface of the conveyor belt running under the rotating drum. A deposition step for obtaining a deposit;
A polymerization step of superimposing the deposit obtained in the recess on the deposit obtained on the conveying surface of the conveyor belt to obtain a polymerized deposit;
A press step of pressurizing and compressing the polymer deposit,
The concave portion is provided with a plurality of suction portions each having a bottom surface made of a porous plate and performing suction from the bottom surface and a non-suction portion that is non-breathable and does not perform suction from the bottom surface, The non-breathable bottom surface of the non-suction part is made of a non-breathable member disposed on the porous plate, and the depth of the non-suction part from the outer peripheral surface of the rotating drum is larger than that of the suction part. Shallow,
In the deposition process, depositing a pre SL material in the recess,
In the pressing step, a method of manufacturing an absorbent body, wherein the polymer deposit is pressurized to obtain an absorbent body having a high density portion and a low density portion having different densities.   The raw material is supplied to the outer peripheral surface of the rotating drum and the conveying surface of the conveyor belt through a duct, and the outer peripheral surface of the rotating drum is supplied from the raw material supply port as a raw material supply path in the duct. The manufacturing method of the absorber of Claim 1 with which the supply path which goes to this and the supply path which goes to the conveyance surface of this conveyor belt from this supply port mutually is provided independently.   The manufacturing method of the absorber of Claim 1 or 2 which makes the surface of the deposit accumulated on the conveyance surface of the said conveyor belt flat before implementation of the said superposition | polymerization process.   The manufacturing method of the absorber as described in any one of Claims 1-3 with which the depth from the rotating drum outer peripheral surface of the said non-suction part is shallower than the depth from the rotating drum outer peripheral surface of the said suction part.   The said absorber is an absorber in which the part corresponding to the said suction part is a high-density part, and the part corresponding to the said non-suction part is a low-density part. Method for manufacturing the absorber.   As the recess, the suction part and the non-suction part are each formed in a shape that is long in the circumferential direction of the rotary drum, and the suction part and the non-suction part are alternately formed in the width direction of the rotary drum. The manufacturing method of the absorber as described in any one of Claims 1-5 using.   The inside of the concave portion is partitioned into a plurality of regions by the non-suction portion extending in the circumferential direction and the width direction of the rotating drum, and each of the regions serves as the suction portion. The manufacturing method of the absorber as described in a term.

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