Absorbent core forming device and method for forming absorbent core

Abstract

To provide an absorbent core forming device capable of reducing placement of high-absorbent polymer particles at unintended positions.SOLUTION: An absorbent core forming device (10) for producing an absorbent core including a high-absorbent polymer, comprises: a conveyance unit (11) that conveys a base sheet (1K) in a conveyance direction; a particle supply unit (12) that supplies high-absorbent polymer particles (12S) toward the base sheet (1K); and an adhesive discharge unit (15) that is disposed on the downstream side in the conveyance direction of the particle supply unit (12) and discharges an adhesive (15H) together with an air flow toward the base sheet (1K). The adhesive discharge unit (15) pushes back at least a part of the high-absorbent polymer particles (12S) which have bounced off the base sheet (1K) toward the base sheet (1K) by the adhesive (15H) discharged from the adhesive discharge unit (15).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an absorbent core forming apparatus and a method for forming an absorbent core.

Background Art

[0002] Conventionally, an apparatus for forming an absorbent core by spraying highly absorbent polymer (SAP) particles onto a material sheet or the like is known. For example, Patent Document 1 discloses a method of forming a composite highly absorbent core structure by mixing an adhesive and SAP powder in air before adhering them to a material sheet and applying the formed mixture to the material sheet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the adhesive and the SAP powder were mixed before being applied to the material sheet (base material sheet). However, when the adhesive and the SAP powder are applied to the base material sheet separately, the released SAP powder may bounce back in an unintended direction and scatter to places where it should not be originally located.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide an absorbent core forming apparatus that reduces the placement of highly absorbent polymer particles at unintended positions.

Means for Solving the Problems

[0006] The main invention for achieving the above object is an absorbent core forming device for manufacturing an absorbent core containing a superabsorbent polymer, which includes a conveying unit for conveying a base sheet in a conveying direction, a particle supply unit for supplying superabsorbent polymer particles toward the base sheet, and an adhesive discharge unit disposed downstream of the particle supply unit in the conveying direction and discharging an adhesive together with an air flow toward the base sheet. The adhesive discharge unit is characterized in that at least a part of the superabsorbent polymer particles rebounded from the base sheet is pushed back toward the base sheet side by the adhesive discharged from the adhesive discharge unit. Other features of the present invention will be clarified by the description in this specification and the accompanying drawings.

Effects of the Invention

[0007] According to the present invention, it is possible to provide an absorbent core forming device that reduces the arrangement of superabsorbent polymer particles at unintended positions.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0009] At least the following matters will become clear from the description of this specification and the attached drawings. Aspect 1 is an absorbent core forming apparatus for manufacturing an absorbent core containing a superabsorbent polymer, comprising a conveying unit that conveys a base sheet in a conveying direction, a particle supply unit that supplies superabsorbent polymer particles toward the base sheet, and an adhesive discharge unit that is disposed downstream of the particle supply unit in the conveying direction and discharges an adhesive toward the base sheet together with an air flow. The adhesive discharge unit is characterized in that at least a part of the superabsorbent polymer particles rebounded from the base sheet is pushed back toward the base sheet side by the adhesive discharged from the adhesive discharge unit.

[0010] According to the absorbent core forming apparatus of Aspect 1, when the discharged adhesive hits the superabsorbent polymer (SAP) particles rebounded from the base sheet, the SAP particles can be dropped back onto the base sheet side again. Further, the placement of SAP particles at unintended positions can be reduced by the air flow discharged together with the adhesive. Furthermore, the fixing of the SAP particles can be made more reliable by the entanglement of the adhesive around the rebounded SAP particles.

[0011] Aspect 2 is the absorbent core forming apparatus according to Aspect 1, wherein an upstream side adhesive application unit that applies an adhesive toward the base sheet is provided upstream of the particle supply unit in the conveying direction.

[0012] According to the absorbent core forming apparatus of Aspect 2, by applying the adhesive in advance before the SAP particles are supplied, the amount of SAP particles rebounding from the base sheet can be reduced, and the placement of SAP particles at unintended positions can be reduced.

[0013] Aspect 3 is the absorbent core forming apparatus according to Aspect 1 or 2, wherein the superabsorbent polymer particles are supplied to the front surface side of the base sheet, and a suction part for sucking the base sheet is provided on the back surface side of the base sheet at the position where the superabsorbent polymer particles are supplied by the particle supply part.

[0014] According to the absorbent core forming apparatus of Aspect 3, by sucking from the back surface side of the base sheet by the suction part, the SAP particles are likely to stay on the base sheet, and the amount of the SAP particles rebounding from the base sheet can be reduced.

[0015] Aspect 4 is the absorbent core forming apparatus according to any one of Aspects 1 to 3, wherein when the adhesive discharge part is the first adhesive discharge part, a second adhesive discharge part for discharging an adhesive together with an air flow toward the base sheet is provided downstream of the first adhesive discharge part in the conveying direction.

[0016] According to the absorbent core forming apparatus of Aspect 4, the amount of rebound can be further reduced by pushing back the rebound of the SAP particles that could not be completely pushed back by the adhesive discharged from the first adhesive discharge part to the base sheet side by the adhesive discharged from the second adhesive discharge part. Also, the fixing of the SAP particles can be performed more reliably.

[0017] Aspect 5 is the absorbent core forming apparatus according to Aspect 4, wherein the first adhesive discharge part and the second adhesive discharge part each have a plurality of discharge port rows in which a plurality of discharge ports are arranged in a row, and the discharge port rows are separated from each other in the conveying direction.

[0018] According to the absorbent core forming apparatus of Aspect 5, since the first adhesive discharge part and the second adhesive discharge part each have a plurality of discharge ports, a plurality of rows of adhesives are applied in the conveying direction, and the rebound of the SAP particles can be further reduced.

[0019] Aspect 6 is the absorbent core forming apparatus according to any one of Aspects 1 to 5, wherein the conveying unit has a conveying conveyor, and the conveying surface of the conveying conveyor is inclined with respect to the horizontal plane such that the downstream side in the conveying direction descends.

[0020] According to the absorbent core forming apparatus of Aspect 6, since the downstream side of the conveying surface is inclined so as to descend, the SAP particles rebounded from the base material sheet are likely to go downstream, and the arrangement of the SAP particles at unintended positions can be reduced.

[0021] Aspect 7 is the absorbent core forming apparatus according to Aspect 6, wherein the adhesive is discharged from the discharge port of the adhesive discharge unit in a predetermined discharge direction, and when the angle at which the conveying surface is inclined with respect to the horizontal plane is θ0, the angle formed by the discharge direction and the horizontal plane is θ0 + 90 degrees or more.

[0022] According to the absorbent core forming apparatus of Aspect 7, by discharging the adhesive at such an angle, the adhesive is discharged so as to cover the SAP particles from the downstream side in the conveying direction, and it becomes easier to capture the rebounded SAP particles.

[0023] Aspect 8 is the absorbent core forming apparatus according to Aspect 7, wherein when the adhesive discharge unit is a first adhesive discharge unit, a second adhesive discharge unit that discharges the adhesive together with an air flow toward the base material sheet is provided downstream of the first adhesive discharge unit in the conveying direction. The second adhesive discharge unit discharges the adhesive from the discharge port in a predetermined discharge direction, and the angle formed by the discharge direction of the second adhesive discharge unit and the horizontal plane is θ0 + 90 degrees or more.

[0024] According to the absorbent core forming apparatus of Aspect 8, by having not only the first adhesive discharge unit but also the second adhesive discharge unit, and the second adhesive discharge unit discharging the adhesive at such an angle, it becomes easier to further capture the rebound of the SAP particles that could not be repelled only by the adhesive discharged from the first adhesive discharge unit.

[0025] Aspect 9 is the absorbent core forming apparatus according to Aspect 8, where the angle formed by the discharge direction of the first adhesive discharge part and the horizontal plane is θ1, and the angle formed by the discharge direction of the second adhesive discharge part and the horizontal plane is θ2, and θ1 < θ2.

[0026] According to the absorbent core forming apparatus of Aspect 9, since the SAP particles bounce back toward the downstream, the second adhesive discharge part arranged downstream of the first adhesive discharge part discharges the adhesive at a more inclined angle, making it easier to capture more SAP particles.

[0027] Aspect 10 is the absorbent core forming apparatus according to any one of Aspects 1 to 5, where the conveying part has a rotating body, the adhesive is discharged from the discharge port of the adhesive discharge part in a predetermined discharge direction, and the angle formed by the virtual line extending the discharge direction and the tangent of the rotating body at the intersection of the virtual line and the outer peripheral surface of the rotating body is greater than 90 degrees, and the upstream side of the discharge direction is inclined toward the downstream side of the conveying direction.

[0028] According to the absorbent core forming apparatus of Aspect 10, with respect to the outer peripheral surface of the rotating body, the discharge direction of the adhesive having such an inclination angle makes it easier to capture the SAP particles that bounce back to the downstream side in the conveying direction.

[0029] Aspect 11 is the absorbent core forming apparatus according to Aspect 10, where when the adhesive discharge part is the first adhesive discharge part, a second adhesive discharge part is provided downstream of the first adhesive discharge part in the conveying direction and discharges the adhesive toward the base sheet together with an air flow. The second adhesive discharge part discharges the adhesive from the discharge port in a predetermined discharge direction, and the angle formed by the virtual line extending the discharge direction of the second adhesive discharge part and the tangent of the rotating body at the intersection of the virtual line and the outer peripheral surface of the rotating body is greater than 90 degrees, and the upstream side of the discharge direction of the second adhesive discharge part is inclined toward the downstream side of the conveying direction.

[0030] According to the absorbent core forming apparatus of Aspect 11, by having not only the first adhesive discharge part but also the second adhesive discharge part, and by discharging the adhesive at such an angle with the second adhesive discharge part as well, it becomes easier to further capture the rebound of the SAP particles that could not be repelled by only the adhesive discharged from the first adhesive discharge part.

[0031] Aspect 12 is the absorbent core forming apparatus according to Aspect 11, where the angle formed by the virtual line extending the first adhesive discharge part and the tangent of the rotating body at the intersection of the virtual line and the outer peripheral surface of the rotating body is θ1, and the angle formed by the virtual line extending the second adhesive discharge part and the tangent of the rotating body at the intersection of the virtual line and the outer peripheral surface of the rotating body is θ2, and θ1 < θ2.

[0032] According to the absorbent core forming apparatus of Aspect 12, since the SAP particles rebound toward the downstream, by discharging the adhesive at a more inclined angle with the second adhesive discharge part arranged downstream of the first adhesive discharge part, it becomes easier to capture the SAP particles.

[0033] Aspect 13 is the absorbent core forming apparatus according to Aspect 12, where the particle supply part supplies the superabsorbent polymer particles in a predetermined supply direction, and the angle formed by the supply direction and the transport surface is less than 90 degrees.

[0034] According to the absorbent core forming apparatus of Aspect 13, by setting the supply direction of the SAP particles at such an angle, the SAP particles are more likely to be supplied toward the downstream side, and the arrangement of the SAP particles at unintended positions can be reduced.

[0035] Aspect 14 is the absorbent core forming apparatus according to any one of Aspects 10 to 13, where the particle supply part supplies the superabsorbent polymer particles in a predetermined supply direction, and the angle formed by the supply virtual line extending the supply direction and the tangent of the rotating body at the intersection of the supply virtual line and the outer peripheral surface of the rotating body is less than 90 degrees.

[0036] According to the absorbent core forming apparatus of Aspect 14, by supplying the SAP particles at such an angle, the particles are more likely to be supplied downstream, and it is possible to reduce the arrangement of the superabsorbent polymer particles at unintended positions.

[0037] Aspect 15 is a method for forming an absorbent core containing a superabsorbent polymer, including a conveying step of conveying a base sheet in a conveying direction, a particle supply step of supplying superabsorbent polymer particles toward the base sheet, and an adhesive discharge step of discharging an adhesive together with an air flow toward the base sheet after the particle supply step. In the adhesive discharge step, at least a part of the superabsorbent polymer particles rebounded from the base sheet is pushed back toward the base sheet side by the adhesive discharged by the adhesive discharge step.

[0038] According to the method for forming an absorbent core of Aspect 15, the discharged adhesive hits the superabsorbent polymer particles rebounded from the base sheet during the particle supply step, so that the superabsorbent polymer particles can be dropped back to the base sheet side again. Also, the air flow discharged together with the adhesive can reduce the arrangement of the superabsorbent polymer particles at unintended positions.

[0039] ===First Embodiment=== Hereinafter, the absorbent core forming apparatus 10 and the method for forming an absorbent core according to the first embodiment will be described. The absorbent core forming apparatus 10 is an apparatus for manufacturing an absorbent core containing a superabsorbent polymer (SAP), and the manufactured absorbent core can be used, for example, in disposable diapers, sanitary napkins, panty liners, water absorption pads, incontinence pads, etc.

[0040] As used herein, the term "particles" when used with the term "superabsorbent polymer (SAP)" encompasses any individual shape or form, and the "particles" can include granules, aggregates, flakes, fibers, spheres, etc., and combinations thereof. Further, the particles can have any desired shape, for example, spherical, polygonal, rod-shaped, polyhedral, or other regular or irregular forms such as circular or angular forms.

[0041] FIG. 1 is a diagram schematically showing a part of the absorbent core forming apparatus 10 of the first embodiment. The absorbent core forming apparatus 10 includes a conveying unit 11 that conveys the base sheet 1K in the conveying direction, a particle supply unit 12 that supplies superabsorbent polymer particles toward the base sheet 1K, and an adhesive discharge unit 15 that discharges an adhesive together with an air flow toward the base sheet 1K. The adhesive discharge unit 15 is disposed downstream in the conveying direction from the particle supply unit 12. Further, the absorbent core forming apparatus 10 of the present embodiment has two adhesive discharge units 15 as the adhesive discharge unit 15, namely, a first adhesive discharge unit 15x1 and a second adhesive discharge unit 15x2 disposed downstream in the conveying direction from the first adhesive discharge unit 15x1.

[0042] The base sheet 1K is a base material of the absorbent core, and superabsorbent polymer (SAP) particles are laminated on the base sheet 1K. The base sheet 1K may be a material that can maintain the state of supporting the SAP particles, and examples thereof include tissue, absorbent paper, non-woven fabric, and the like. The conveying unit 11 includes a conveying conveyor 11cn and a plurality of conveying rollers 11rn, etc. Regarding the conveying roller 11rn, it may be a driving roller that is driven to rotate by a driving source such as a motor, or a driven roller that rotates passively without a driving source. Further, the conveying conveyor 11cn is preferably a suction belt conveyor that uses the upper surface of an endless belt that rotates drivenly as a conveying surface and conveys the base sheet 1K while adsorbing it with a plurality of air intake holes (a suction unit described later) provided on the conveying surface.

[0043] Figures 2A and 2B are diagrams for explaining the modes of supply of SAP particles and discharge of the adhesive in the first embodiment. As shown in FIGS. 1 and 2A, in the absorbent core forming apparatus 10, first, the base sheet 1K is fed in the conveying direction (conveying step), and then, SAP particles 12S are supplied from the particle supply unit 12 toward the surface of the running base sheet 1K (particle supply step). And immediately after the particle supply step, the adhesive discharge unit 15 (the first adhesive discharge unit 15x1) discharges the adhesive 15H together with an air flow toward the base sheet 1K (adhesive discharge step). The adhesive 15H is, here, a hot melt adhesive and is discharged from a plurality of discharge ports (nozzles) provided in the adhesive discharge unit 15, the details of which will be described later.

[0044] After the first adhesive discharge unit 15x1 discharges the adhesive 15H, the second adhesive discharge unit 15x2 installed downstream of the first adhesive discharge unit 15x1 in the conveying direction further discharges the adhesive 15H together with an air flow toward the base sheet 1K.

[0045] Note that the adhesive 15H is discharged together with an air flow. In this embodiment, the pressure of this air flow is the same for both the first adhesive discharge unit 15x1 and the second adhesive discharge unit 15x2. However, it is not limited thereto, and they may have different air pressures. Also, the distance from the supply port of the particle supply unit 12 that supplies the SAP particles to the conveying surface 11m of the conveying conveyor 11cn is preferably about 7 mm, and the distance from the discharge port of the adhesive discharge unit 15 to the conveying surface 11m of the conveying conveyor 11cn is preferably about 30 mm ± 10 mm.

[0046] After the second adhesive discharge unit 15x2 discharges the adhesive 15H onto the base sheet 1K, another sheet material 1S merges to cover the SAP particles 12S, and is further cut to a desired size downstream, thereby forming the absorbent core. In this embodiment, another sheet material 1S is laminated after the SAP particles are supplied onto the base sheet 1K, but the present invention is not limited to this. For example, an absorbent core can be formed by simply cutting the base sheet 1K to a desired size after laminating the SAP particles on the base sheet 1K, or an absorbent core may be formed by laminating pulp fibers after laminating the SAP particles on the base sheet 1K. Further, when mixing another liquid absorbent material such as pulp fibers in addition to the SAP particles as the material of the absorbent core, such a liquid absorbent material may be supplied to the base sheet 1K before or after the particle supply unit 12 supplies the SAP particles 12S.

[0047] As described above, when forming a sheet containing SAP by discharging the SAP particles 12S, usually, the SAP particles 12S are gravity-fed toward the transport surface 11m or discharged together with pressurized air. Then, the discharged SAP particles 12S are likely to bounce back when hitting the transport surface 11m (base sheet 1K) (see FIG. 2A). In this embodiment, it is assumed that about 60% of the SAP particles 12S supplied at one time bounce back. Further, the discharged SAP particles 12S are likely to bounce back in an unintended direction, and there is a risk of scattering to places where they should not be arranged.

[0048] Regarding this point, in the absorbent core forming apparatus 10 of the present embodiment, as shown in FIG. 2A, at least a part of the SAP particles 12S rebounded from the base material sheet 1K can be pushed back toward the base material sheet 1K side by the adhesive 15H discharged from the adhesive discharge part 15. Here, "pushing back" means moving the SAP particles 12S in a direction opposite to the conveyance direction and in the direction of gravity (vertically downward). That is, when the discharged adhesive 15H hits the SAP particles 12S rebounded from the base material sheet 1K, the SAP particles 12S can be dropped again toward the base material sheet 1K side. Further, the air flow discharged together with the adhesive 15H can reduce the possibility that the SAP particles 12S are arranged at unintended positions. And by the adhesive 15H entangling around the rebounded SAP particles 12S, the fixing of the SAP particles 12S can be performed more reliably.

[0049] Also, in the present embodiment, not only the adhesive 15H discharged from the first adhesive discharge part 15x1 but also the adhesive 15H is discharged from the second adhesive discharge part 15x2 provided downstream in the conveyance direction from the first adhesive discharge part 15x1. Thereby, the rebounding of the SAP particles 12S that could not be completely pushed back by the adhesive 15H discharged from the first adhesive discharge part 15x1 is pushed back toward the base material sheet 1K side by the adhesive 15H discharged from the second adhesive discharge part 15x2, so that the rebounding amount can be further reduced. By doing so, the fixing of the SAP particles 12S can be performed more reliably.

[0050] Note that the absorbent core forming apparatus 10 of the present embodiment has two adhesive discharge parts 15 (the first adhesive discharge part 15x1 and the second adhesive discharge part 15x2), but is not limited thereto. For example, when the amount of the supplied SAP particles 12S is small, only the first adhesive discharge part 15x1 may be sufficient. Also, although the first adhesive discharge part 15x1 and the second adhesive discharge part 15x2 can push back the rebounded SAP particles 12S, the first adhesive discharge part 15x1 emphasizes fixing the SAP particles 12S to the base material sheet 1K, and the second adhesive discharge part 15x2 can be designed mainly for the purpose of improving the adhesion strength of materials (such as the base material sheet 1K) and adjusting the strength.

[0051] In addition, in the present embodiment, the first adhesive discharge unit 15x1 and the second adhesive discharge unit 15x2 are separated to increase the degree of freedom of each adhesive discharge unit 15. However, the first adhesive discharge unit 15x1 and the second adhesive discharge unit 15x2 may be an integrated adhesive discharge unit. When the first adhesive discharge unit 15x1 and the second adhesive discharge unit 15x2 are installed as an integrated unit, the cost can be reduced compared to installing separate devices, and the maintenance and management of the device also become easier.

[0052] As described above, when the SAP particles 12S are supplied from the particle supply unit 12, the SAP particles 12S are likely to bounce back. Therefore, in the present embodiment, as shown in FIG. 2B, the conveying surface 11m of the conveying conveyor 11cn is inclined with respect to the horizontal plane Hr such that the downstream side in the conveying direction descends. By doing so, the SAP particles 12S rebounded from the base material sheet 1K are likely to move downstream by gravity, and the arrangement of the SAP particles 12S at unintended positions can be reduced.

[0053] When the angle at which the conveying surface 11m shown in FIG. 2B is inclined with respect to the horizontal plane Hr is θ0, the inclination angle θ0 in the present embodiment is about 30 degrees. This is because the angle of repose of the SAP particles (the maximum angle of the inclined plane that maintains stability without collapsing when the particles are stacked) is 32 degrees to 38 degrees, and the inclination angle is set in the vicinity of this angle. By setting the inclination angle θ0 to about 30 degrees, it is possible to prevent the SAP particles 12S discharged from the particle supply unit 12 from rolling after getting on the conveying surface 11m, and to make it less likely to bounce back compared to the case of discharging onto a conveying surface parallel to the horizontal plane. The inclination angle θ0 when the conveying surface 11m of the conveying conveyor 11cn is inclined such that the downstream side descends can be set up to about 75 degrees.

[0054] Note that, as described above, it is preferable that the transport surface 11m is inclined with respect to the horizontal plane Hr such that the downstream side in the transport direction descends, but it is not limited thereto. For example, the transport surface 11m may be horizontal, or may be inclined with respect to the horizontal plane Hr such that the upstream side in the transport direction descends. Even if it is inclined such that the upstream side in the transport direction descends (that is, the downstream side ascends), if the transport conveyor 11cn is a suction belt conveyor and the suction force for sucking the base material sheet 1K is increased, it is possible to similarly suppress the rebound of the SAP particles 12S. When the transport surface 11m is inclined with respect to the horizontal plane Hr such that the upstream side in the transport direction descends, the inclination angle θ0 can be up to about 45 degrees, but preferably up to about 30 degrees.

[0055] Returning to FIGS. 2A and 2B, when the transport surface 11m is inclined with respect to the horizontal plane Hr such that the downstream side descends and the inclination angle θ0 is 30 degrees, on the transport surface 11m, the distance L1 from the position where the SAP particles 12S are supplied to the position where the adhesive 15H is discharged from the first adhesive discharge portion 15x1 is preferably in the range of 0 mm to 50 mm, more preferably 25 mm. Similarly, on the transport surface 11m, the distance L2 from the position where the SAP particles 12S are supplied to the position where the adhesive 15H is discharged from the second adhesive discharge portion 15x2 is preferably in the range of 50 mm to 300 mm, more preferably 100 mm. By discharging the adhesive 15H from the first adhesive discharge portion 15x1 and the second adhesive discharge portion 15x2 within such a range, it becomes easier to effectively apply the adhesive 15H to the rebounded SAP particles 12S, and it also becomes easier to entangle the adhesive 15H around the rebounded SAP particles 12S.

[0056] As shown in FIG. 2B, the adhesive 15H is discharged from the discharge ports (discharge ports 15t1 etc. in FIG. 3 described later) of the respective adhesive discharge parts 15 (the first adhesive discharge part 15x1 and the second adhesive discharge part 15x2) in a predetermined discharge direction. Here, the "discharge direction" is the direction along the central axis of the discharge ports (15t1, 15t2) formed on the tip surface of the adhesive discharge part 15. The central axis passes through the center of gravity of the discharge port and is perpendicular to the tip surface. For example, when the discharge port is circular, it is a straight line passing through the center of the circle and perpendicular to the plane of the circle. When the discharge port is rectangular, it means a straight line passing through the intersection of the diagonals of the rectangle and perpendicular to the rectangular surface.

[0057] And, as shown in FIG. 2B, when the angle at which the conveyance surface 11m is inclined with respect to the horizontal plane Hr is θ0, the angle θ1 formed by the discharge direction 15d1 of the adhesive 15H discharged from the discharge port 15t1 of the first adhesive discharge part 15x1 (adhesive discharge part 15) and the horizontal plane Hr is preferably θ0 + 90 degrees or more. Preferably, the angle θ1 is in the range of θ0 + 90 degrees to θ0 + 110 degrees. By doing so, it is possible to discharge the adhesive 15H so as to cover the SAP particles 12S from the downstream side rather than discharging the adhesive 15H perpendicularly to the conveyance surface 11m, and it becomes easier to capture the SAP particles 12S rebounded to the downstream side.

[0058] Also, the second adhesive discharge part 15x2 provided downstream in the conveyance direction from the first adhesive discharge part 15x1 also discharges the adhesive 15H from the discharge port 15t2 in a predetermined discharge direction 15d2. And, similarly, the angle θ2 formed by the discharge direction 15d2 of the second adhesive discharge part 15x2 and the horizontal plane Hr is preferably θ0 + 90 degrees or more. By discharging the adhesive 15H at such an angle not only for the first adhesive discharge part 15x1 but also for the second adhesive discharge part 15x2, it becomes easier to capture the rebounding of the SAP particles 12S that could not be repelled only by the adhesive 15H discharged from the first adhesive discharge part 15x1.

[0059] Further, in the absorbent core forming apparatus 10 of the present embodiment, it is preferable that the angle θ2 formed between the discharge direction 15d2 of the second adhesive discharge unit 15x2 and the horizontal plane Hr is larger than the angle θ1 formed between the discharge direction 15d1 of the first adhesive discharge unit 15x1 and the horizontal plane Hr (θ1 < θ2). Since the SAP particles 12S bounce back toward the downstream side in the conveyance direction, the second adhesive discharge unit 15x2 disposed downstream of the first adhesive discharge unit 15x1 discharges the adhesive 15H at an angle inclined more toward the downstream side, so that the adhesive 15H of the second adhesive discharge unit 15x2 is easily discharged from the downstream side toward the upstream side, and it becomes easier to push back the SAP particles 12S that have fallen to the downstream side.

[0060] As shown in FIGS. 2A and 2B, when the particle supply unit 12 supplies the SAP particles 12S toward the base material sheet 1K, the SAP particles 12S are supplied in a predetermined supply direction 12d. The "supply direction" is, similar to the above-described discharge direction, the direction along the central axis of the supply port formed on the tip surface of the particle supply unit 12. The central axis passes through the center of gravity of the supply port and is perpendicular to the tip surface. For example, when the supply port is circular, it is a straight line passing through the center of the circle and perpendicular to the plane of the circle. When the supply port is rectangular, it means a straight line passing through the intersection of the diagonals of the rectangle and perpendicular to the rectangular surface. And the angle θ3 formed between the supply direction 12d of the SAP particles 12S and the conveyance surface 11m is preferably less than 90 degrees. By supplying the SAP particles 12S so that θ3 is less than 90 degrees, the SAP particles 12S are more easily supplied toward the downstream side. Thereby, it is possible to reduce the SAP particles 12S being disposed at an unintended position.

[0061] Also, as shown in FIG. 1, in the absorbent core forming apparatus 10, an upstream-side adhesive application unit 16 that applies an adhesive toward the base sheet 1K may be provided upstream in the transport direction from the particle supply unit 12 that supplies the SAP particles 12S. By applying the adhesive to the base sheet 1K in advance before the SAP particles 12S are supplied to the base sheet 1K by the particle supply unit 12, the SAP particles 12S are more likely to stick to the base sheet 1K, and the amount of rebound of the SAP particles 12S can be reduced. Thereby, it is possible to suppress the SAP particles 12S from being arranged at unintended positions.

[0062] Also, as described above, when the transport conveyor 11cn is a suction belt conveyor that has a plurality of intake holes on its transport surface 11m and transports the base sheet 1K while adsorbing it, the supplied SAP particles 12S also tend to stay on the base sheet 1K due to the intake of the conveyor. Specifically, the SAP particles 12S are supplied to the front surface side of the base sheet 1K, but a suction portion 11P (intake hole) that sucks the base sheet 1K is provided on the back surface side of the base sheet 1K at the position where the SAP particles 12S are supplied. Due to the suction of the suction portion 11P, the SAP particles 12S are more likely to adhere to the base sheet 1K. By doing so, the amount of the SAP particles 12S rebounding from the base sheet 1K can be reduced. Note that a mesh belt may be used as the conveyor belt sucked by the suction portion 11P.

[0063] FIG. 3 is a plan view of the surface of the adhesive discharge unit 15 (the first adhesive discharge unit 15x1) where the discharge port 15t1 is provided. When the direction orthogonal to the conveyance direction is defined as the intersecting direction, as shown in FIG. 3, a plurality of discharge ports 15t1 of the adhesive discharge unit 15 are provided at intervals in the intersecting direction. Specifically, in the present embodiment, five discharge ports 15t1 (15t2) are provided at intervals in the intersecting direction. When the five provided rows are defined as the discharge port row 15R, the adhesive discharge unit 15 has two rows, namely, the discharge port row 15R1 on the upstream side in the conveyance direction and the discharge port row 15R2 on the downstream side in the conveyance direction. That is, the first adhesive discharge unit 15x1 and the second adhesive discharge unit 15x2 each have a plurality of discharge port rows 15R in which a plurality of discharge ports 15t1 (15t2) are arranged in a row and are separated from each other in the conveyance direction. Further, each discharge port 15t1 (15t2) is composed of three nozzles. In other words, the discharge port 15t1 (15t2) is composed of a set of three small discharge ports. Here, since five discharge ports 15t1 are arranged along the intersecting direction in each discharge port row 15R (15R1, 15R2), the adhesive discharge unit 15 has a total of ten discharge ports 15t1. By the first adhesive discharge unit 15x1 and the second adhesive discharge unit 15x2 each having a plurality of discharge ports 15t1 (15t2), the application of the adhesive 15H in a plurality of rows in the conveyance direction can be performed, and the bounce-back of the SAP particles 12S can be further reduced.

[0064] In each discharge port row 15R, the distance L3 between the discharge ports 15t1 adjacent to each other in the crossing direction is preferably about 5 mm. Further, the interval L4 in the conveyance direction between the discharge port 15t1 of the discharge port row 15R1 and the discharge port 15t1 of the discharge port row 15R2 is preferably about 3.5 mm apart. Among the discharge ports 15t1 in the discharge port row 15R1, the discharge port 15t1 located on the outermost side in the crossing direction is defined as the discharge port 15t1a, and the discharge port 15t1 adjacent to the discharge port 15t1a on the other side in the crossing direction is defined as the discharge port 15t1b. Among the discharge ports 15t1 in the discharge port row 15R2, the discharge port 15t1 located on the outermost side in the crossing direction is defined as the discharge port 15t1c, and the discharge port 15t1 adjacent to the discharge port 15t1c on the other side in the crossing direction is defined as the discharge port 15t1d. When this is done, the discharge port 15t1c does not overlap with the discharge ports 15t1a and 15t1b in the crossing direction, and is located between the discharge ports 15t1a and 15t1b in the crossing direction. Similarly, the discharge port 15t1b does not overlap with the discharge ports 15t1c and 15t1d in the crossing direction, and is located between the discharge ports 15t1c and 15t1d in the crossing direction. By arranging them in this way, when the adhesive 15H is discharged, the adhesive 15H is coated in a net shape in terms of planar shape or degree of air in the crossing direction, reducing the loss of capturing the rebounded SAP particles, and also making it easier for the adhesive 15H to entangle with more SAP particles.

[0065] Furthermore, each discharge port 15t1 (15t2) has three nozzles respectively. Among the three nozzles, the adhesive 15H discharged from the middle nozzle is discharged so as to fall straight down, and it is desirable that the adhesive 15H discharged from the left and right nozzles is discharged in a direction of pushing back the rebounded SAP particles toward the base sheet 1K side, and it is more desirable that they are discharged at an angle toward the outside in the crossing direction. By doing so, the adhesive 15H is more likely to be discharged in a planar or net shape, and is more likely to entangle with more SAP particles.

[0066] ===Second Embodiment=== Next, based on FIGS. 4, 5A, and 5B, the absorbent core forming apparatus 10 according to the second embodiment will be described. FIG. 4 is a diagram schematically showing a part of the absorbent core forming apparatus 10 of the second embodiment. FIGS. 5A and 5B are diagrams for explaining the mode of supply of SAP particles and discharge of the adhesive in the second embodiment.

[0067] The basic configuration of the absorbent core forming apparatus 10 in the second embodiment is the same as that of the absorbent core forming apparatus 10 according to the first embodiment. In the second embodiment, the conveying unit 11' that conveys the base sheet 1K in the conveying direction is different in that it has a rotating body 11tn instead of the conveying conveyor 11cn. In the following description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description of the parts common to the first embodiment is omitted.

[0068] As shown in FIGS. 4 and 5A, in the absorbent core forming apparatus 10 according to the second embodiment, the base sheet 1K is conveyed in a state of being in contact with the outer peripheral surface 11n of the rotating body 11tn that rotates in the conveying direction (conveying step). Similar to the first embodiment, the particle supply unit 12 supplies SAP particles 12S toward the surface of the base sheet 1K (particle supply step). Immediately after the particle supply step, the first adhesive discharge unit 15x1 (adhesive discharge unit 15) discharges the adhesive 15H together with an air flow, and further downstream, the second adhesive discharge unit 15x2 discharges the adhesive 15H toward the base sheet 1K together with an air flow (adhesive discharge step).

[0069] Note that it is desirable for the rotating body 11tn to have a plurality of intake holes (not shown) on its circumferential surface, and to include a suction mechanism (suction unit) that sucks and holds the base sheet 1K by sucking to the inner peripheral side of the rotating body 11tn through the intake holes. Thereby, the SAP particles 12S are likely to remain on the base sheet 1K.

[0070] As shown in FIGS. 5A and 5B, also in the second embodiment, the adhesive 15H is discharged from the discharge ports of the respective adhesive discharge portions 15 (the first adhesive discharge portion 15x1 and the second adhesive discharge portion 15x2) in a predetermined discharge direction. Specifically, in the first adhesive discharge portion 15x1, the adhesive 15H is discharged from the discharge port 15t1 of the first adhesive discharge portion 15x1 in a predetermined discharge direction 15d1, and the upstream side of the discharge direction 15d1 is inclined toward the downstream side of the conveyance direction so that the angle θ1 formed by the virtual line V1 extending the discharge direction 15d1 and the tangent line G1 of the rotating body 11tn at the intersection point P1 between the virtual line V1 and the outer peripheral surface 11n of the rotating body 11tn is greater than 90 degrees. Since a part of the supplied SAP particles 12S bounces back toward the downstream in the conveyance direction, by discharging the adhesive 15H so as to cover the SAP particles 12S from the downstream side rather than discharging the adhesive 15H perpendicularly to the outer peripheral surface 11n, it becomes easier to push back the SAP particles 12S that have bounced back to the downstream side.

[0071] Also in the second embodiment, the second adhesive discharge portion 15x2 is provided downstream of the first adhesive discharge portion 15x1 in the conveyance direction. Similar to the first adhesive discharge portion 15x1, the second adhesive discharge portion 15x2 discharges the adhesive 15H from the discharge port 15t2 in a predetermined discharge direction 15d2. And the upstream side of the discharge direction 15d2 of the second adhesive discharge portion 15x2 is inclined toward the downstream side of the conveyance direction so that the angle θ2 formed by the virtual line V2 extending the discharge direction 15d2 of the second adhesive discharge portion 15x2 and the tangent line G2 of the rotating body 11tn at the intersection point P2 between the virtual line V2 and the outer peripheral surface 11n of the rotating body 11tn is greater than 90 degrees (FIG. 5B). In the absorbent core forming apparatus 10, by discharging the adhesive 15H at such an angle not only from the first adhesive discharge portion 15x1 but also from the second adhesive discharge portion 15x2, it becomes easier to further capture the bouncing back of the SAP particles 12S that could not be completely pushed back by the adhesive 15H discharged from the first adhesive discharge portion 15x1.

[0072] In addition, the angle θ2 formed by the virtual line V2 obtained by extending the second adhesive discharge portion 15x2 and the tangent line G2 of the rotating body 11tn at the intersection point P2 between the virtual line V2 and the outer peripheral surface 11n of the rotating body 11tn is larger than the angle θ1 formed by the virtual line V1 obtained by extending the first adhesive discharge portion 15x1 and the tangent line G1 of the rotating body 11tn at the intersection point P1 between the virtual line V1 and the outer peripheral surface 11n of the rotating body 11tn (θ1 < θ2). Since the supplied SAP particles 12S are likely to bounce back toward the downstream in the conveyance direction, the second adhesive discharge portion 15x2 disposed downstream of the first adhesive discharge portion 15x1 discharges the adhesive 15H at a more inclined angle, making it easier to capture the SAP particles 12S that have fallen to the downstream side.

[0073] FIG. 6 is a diagram showing the tangent line G1 and a line Hr parallel to the horizontal line. In the first embodiment, the conveyance surface 11m of the conveyance conveyor 11cn is inclined with respect to the horizontal plane Hr such that the downstream side in the conveyance direction descends. However, also in the second embodiment, based on the same principle, it is desirable to set the discharge direction 15d1 of the first adhesive discharge portion 15x1. Specifically, as shown in FIG. 6, when the intersection point between the virtual line V1, which is a line obtained by extending the discharge direction 15d1 of the first adhesive discharge portion 15x1, and the outer peripheral surface 11n of the rotating body 11tn is the intersection point P1, and the angle formed by the tangent line G1 of the rotating body 11tn at the intersection point P1 and the line Hr parallel to the horizontal line is θ4, it is preferable to set the discharge direction 15d1 of the first adhesive discharge portion 15x1 such that θ4 is approximately 30 degrees. By doing so, it is possible to easily push back the SAP particles 12S that have bounced back from the base material sheet 1K toward the base material sheet 1K side by the adhesive 15H discharged from the adhesive discharge portion 15x1.

[0074] Returning to FIG. 5B, when the particle supply unit 12 supplies the SAP particles 12S to the base sheet 1K, the SAP particles 12S are supplied in a predetermined supply direction 12d. The angle θ3 formed by the supply virtual line V3 extending in the supply direction 12d and the tangent line G3 of the rotating body 11tn at the intersection point P3 between the supply virtual line V3 and the outer peripheral surface 11n of the rotating body 11tn is preferably less than 90 degrees. By doing so, the upstream side of the supply direction 12d is inclined toward the upstream side of the transport direction, and the downstream side of the supply direction 12d faces the downstream side of the transport direction. As a result, the SAP particles 12S can easily flow downstream. Consequently, the arrangement of the SAP particles 12S at unintended positions can be reduced.

[0075] Note that, as shown in FIG. 4, the SAP particle supply position of the particle supply unit 12 in the second embodiment is the uppermost position of the rotating body 11tn, but it is not limited thereto. The supply position of the SAP particles 12S can be, for example, up to a position moved 30 degrees upstream or 60 degrees downstream from the line connecting the uppermost position and the center of the rotating body 11tn. Preferably, it is in the range up to a position moved 20 degrees upstream or 10 degrees downstream, and more preferably, it is supplied directly above the uppermost position of the rotating body 11tn (that is, θ3 becomes 90 degrees).

[0076] Also, as shown in FIG. 4, in the absorbent core forming apparatus 10 of the present embodiment, an upstream adhesive application unit 16 for applying an adhesive toward the base sheet 1K may be provided upstream of the particle supply unit 12 that supplies the SAP particles 12S in the transport direction. By applying the adhesive to the base sheet 1K in advance before the SAP particles 12S are supplied, the SAP particles 12S can easily adhere to the base sheet 1K, and the amount of the SAP particles 12S rebounding from the base sheet 1K can be reduced. Thereby, the arrangement of the SAP particles 12S at unintended positions can be suppressed.

[0077] ===Others=== The above-described embodiments are for facilitating the understanding of the present invention and are not for limiting the interpretation of the present invention. It goes without saying that the present invention can be changed and improved without departing from its gist, and equivalents thereof are included in the present invention.

[0078] In the above-described first and second embodiments, the discharge direction 15d1 of the first adhesive discharge portion 15x1 was set such that the upstream side of the discharge direction 15d1 inclined toward the downstream side of the conveyance direction. However, the present invention is not limited thereto. Conversely, it may be set such that the upstream side of the discharge direction 15d1 inclines toward the upstream side of the conveyance direction. FIG. 7 is a diagram showing a modified example of the discharge direction 15d1 of the first adhesive discharge portion 15x1. In the modified example shown in FIG. 7, the discharge direction 15d1 (solid line) of the first adhesive discharge portion 15x1 is set such that the upstream side of the discharge direction 15d1 inclines toward the upstream side of the conveyance direction. In this case, the inclination range of the discharge direction 15d1 is preferably in the range where the angle θ5 formed by the perpendicular line Ve with respect to the conveyance surface 11m of the conveyance conveyor 11cn or the outer peripheral surface 11n of the rotating body 11tn and the discharge direction 15d1 is from 0 degree to about 20 degrees.

[0079] In FIG. 7, the discharge direction 15d1 when the upstream side of the discharge direction 15d1 inclines toward the downstream side of the conveyance direction is shown by a dotted line. Similarly, in this case, the inclination range of the discharge direction 15d1 is preferably in the range where the angle θ6 formed by the perpendicular line Ve and the discharge direction 15d1 is from 0 degree to about 20 degrees. When the angles θ5 and θ6 are within the above-described ranges, the rebounded SAP particles can be effectively pushed back toward the base material sheet 1K side. Similarly, for the discharge direction 15d2 of the second adhesive discharge portion 15x2, it may be set such that the upstream side of the discharge direction 15d2 inclines toward the upstream side of the conveyance direction.

Explanation of Reference Numerals

[0080] 1K Base material sheet 1S Another sheet material 10 Absorbent core forming device 11 Conveying portion, 11’ Conveying portion 11cn Conveyance conveyor 11m Conveyance surface 11n outer peripheral surface 11P suction part 11rn conveying roller 11tn rotating body 12 particle supply part 12d supply direction 12S superabsorbent polymer (SAP) particles 15 adhesive discharge part 15d1 discharge direction 15d2 discharge direction 15H adhesive 15R discharge port row 15R1 discharge port row 15R2 discharge port row 15t1 discharge port 15t1a, 15t1b, 15t1c, 15t1d discharge ports 15t2 discharge port 15x1 first adhesive discharge part 15x2 second adhesive discharge part 16 upstream adhesive coating part

Claims

1. An absorbent core forming apparatus for manufacturing an absorbent core containing a superabsorbent polymer, comprising: a conveying unit configured to convey a base sheet in a conveying direction; a particle supply unit configured to supply superabsorbent polymer particles toward the base sheet; an adhesive discharge unit disposed downstream of the particle supply unit in the conveying direction and configured to discharge an adhesive together with an air flow toward the base sheet; wherein the adhesive discharge unit is configured to push back at least a part of the superabsorbent polymer particles rebounded from the base sheet toward the base sheet side by the adhesive discharged from the adhesive discharge unit; an absorbent core forming apparatus, characterized by the above.

2. The absorbent core forming apparatus according to claim 1, wherein an upstream-side adhesive application unit configured to apply an adhesive toward the base sheet is provided upstream of the particle supply unit in the conveying direction. an absorbent core forming apparatus, characterized by the above.

3. The absorbent core forming apparatus according to claim 1 or 2, wherein the superabsorbent polymer particles are supplied to the surface side of the base sheet, and a suction unit configured to suck the base sheet is provided on the back side of the base sheet at a position where the superabsorbent polymer particles are supplied by the particle supply unit. an absorbent core forming apparatus, characterized by the above.

4. The absorbent core forming apparatus according to claim 1 or 2, wherein when the adhesive discharge unit is a first adhesive discharge unit, a second adhesive discharge unit configured to discharge an adhesive together with an air flow toward the base sheet is provided downstream of the first adhesive discharge unit in the conveying direction. an absorbent core forming apparatus, characterized by the above.

5. The absorbent core forming apparatus according to claim 4, wherein the first adhesive discharge unit and the second adhesive discharge unit each have a plurality of discharge port rows in which a plurality of discharge ports are arranged in a row and are spaced apart from each other in the conveying direction. an absorbent core forming apparatus, characterized by the above.

6. The absorbent core forming apparatus according to claim 1 or 2, wherein the conveying unit includes a conveying conveyor, and a conveying surface of the conveying conveyor is inclined with respect to a horizontal plane such that a downstream side in the conveying direction is lowered. an absorbent core forming apparatus, characterized by the above.

7. The absorbent core forming apparatus according to claim 6, wherein the adhesive is discharged from a discharge port of the adhesive discharge unit in a predetermined discharge direction, and when an angle at which the conveying surface is inclined with respect to the horizontal plane is θ0, an angle formed by the discharge direction and the horizontal plane is θ0 + 90 degrees or more. An absorbent core forming device characterized by the following.

8. The absorbent core forming device according to claim 7, when the adhesive discharge part is used as the first adhesive discharge part, a second adhesive discharge part that discharges an adhesive together with an air flow toward the base material sheet is provided downstream of the first adhesive discharge part in the conveyance direction, the second adhesive discharge part discharges the adhesive from the discharge port in a predetermined discharge direction, the angle formed by the discharge direction of the second adhesive discharge part and the horizontal plane is θ0 + 90 degrees or more An absorbent core forming device characterized by the following.

9. The absorbent core forming device according to claim 8, when the angle formed by the discharge direction of the first adhesive discharge part and the horizontal plane is θ1, and the angle formed by the discharge direction of the second adhesive discharge part and the horizontal plane is θ2, θ1 < θ2 An absorbent core forming device characterized by the following.

10. The absorbent core forming device according to claim 1 or 2, the conveyance part has a rotating body, the adhesive is discharged from the discharge port of the adhesive discharge part in a predetermined discharge direction, the upstream side in the discharge direction is inclined toward the downstream side in the conveyance direction so that the angle formed by the virtual line extending the discharge direction and the tangent line of the rotating body at the intersection of the virtual line and the outer peripheral surface of the rotating body is greater than 90 degrees An absorbent core forming device characterized by the following.

11. The absorbent core forming device according to claim 10, when the adhesive discharge part is used as the first adhesive discharge part, a second adhesive discharge part that discharges an adhesive together with an air flow toward the base material sheet is provided downstream of the first adhesive discharge part in the conveyance direction, the second adhesive discharge part discharges the adhesive from the discharge port in a predetermined discharge direction, the upstream side in the discharge direction of the second adhesive discharge part is inclined toward the downstream side in the conveyance direction so that the angle formed by the virtual line extending the discharge direction of the second adhesive discharge part and the tangent line of the rotating body at the intersection of the virtual line and the outer peripheral surface of the rotating body is greater than 90 degrees An absorbent core forming device characterized by the following.

12. The absorbent core forming device according to claim 11, when the angle formed by the virtual line extending the first adhesive discharge part and the tangent line of the rotating body at the intersection of the virtual line and the outer peripheral surface of the rotating body is θ1, and the angle formed by the virtual line extending the second adhesive discharge part and the tangent line of the rotating body at the intersection of the virtual line and the outer peripheral surface of the rotating body is θ2, θ1 < θ2 An absorbent core forming apparatus characterized by this.

13. The absorbent core forming apparatus according to Claim 6, wherein the particle supply unit supplies the superabsorbent polymer particles in a predetermined supply direction, and the angle formed by the supply direction and the conveyance surface is less than 90 degrees An absorbent core forming apparatus characterized by this.

14. The absorbent core forming apparatus according to Claim 10, wherein the particle supply unit supplies the superabsorbent polymer particles in a predetermined supply direction, and the angle formed by a supply virtual line extending the supply direction and a tangent to the rotating body at the intersection of the supply virtual line and the outer peripheral surface of the rotating body is less than 90 degrees An absorbent core forming apparatus characterized by this.

15. A method for forming an absorbent core containing a superabsorbent polymer, comprising a conveyance step of conveying a base sheet in a conveyance direction, a particle supply step of supplying superabsorbent polymer particles toward the base sheet, and an adhesive discharge step of discharging an adhesive together with an air flow toward the base sheet after the particle supply step, wherein in the adhesive discharge step, at least a part of the superabsorbent polymer particles rebounded from the base sheet by the adhesive discharged by the adhesive discharge step is pushed back toward the base sheet side by the adhesive A method for forming an absorbent core, characterized by this.

Images