Absorbent core formation device and method for forming absorbent core

Abstract

An absorbent core formation device (10) for manufacturing an absorbent core containing a highly absorbent polymer, said device comprising: a conveyance part (11) that conveys a base material sheet (1K) in a conveyance direction; a particle supply part (12) that supplies highly absorbent polymer particles (12S) toward the base material sheet (1K); and an adhesive agent ejection part (15) that is disposed downstream of the particle supply part (12) in the conveyance direction and ejects an adhesive agent (15H) toward the base material sheet (1K) together with a stream of air, wherein the adhesive agent ejection part (15) pushes at least some of the highly absorbent polymer particles (12S) which have bounced up from the base material sheet (1K) back toward the base material sheet (1K) by means of the adhesive agent (15H) ejected from the adhesive agent ejection part (15).

Description

Apparatus for forming an absorbent core and method for forming an absorbent core

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

[0002] Conventionally, there are known devices for forming an absorbent core by spraying superabsorbent polymer (SAP) particles onto a material sheet, etc. For example, Patent Document 1 discloses a method for forming a composite superabsorbent core structure by mixing an adhesive and SAP powder in air before adhering them to a material sheet, and applying the resulting mixture to the material sheet.

[0003] JP 2013-141609 A

[0004] In Patent Document 1, the adhesive and SAP powder are mixed before being applied to the material sheet (base sheet). However, when the adhesive and SAP powder are applied separately to the base sheet, the released SAP powder can bounce off in unintended directions and end up scattering in places where it should not have been placed.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide an absorbent core forming device that reduces the placement of high-absorbent polymer particles in unintended locations.

[0006] The main invention for achieving the above object is an absorbent core forming apparatus for manufacturing an absorbent core containing a superabsorbent polymer, the absorbent core forming apparatus comprising: a conveying section for conveying a base sheet in a conveying direction; a particle supplying section for supplying superabsorbent polymer particles toward the base sheet; and an adhesive discharging section disposed downstream of the particle supplying section in the conveying direction for discharging adhesive together with an air flow toward the base sheet, the adhesive discharging section being characterized in that the adhesive discharged from the adhesive discharging section pushes back toward the base sheet at least a portion of the superabsorbent polymer particles that have rebounded from the base sheet. Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

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

[0008] 2A and 2B are diagrams illustrating the supply of SAP particles and the discharge of adhesive in the first embodiment. A plan view of the surface of the adhesive discharge unit 15 on which the discharge port 15t1 is provided. A diagram illustrating the supply of SAP particles and the discharge of adhesive in the second embodiment. A diagram illustrating the supply of SAP particles and the discharge of adhesive in the second embodiment. A diagram illustrating a modified example of the discharge direction 15d1 of the first adhesive discharge unit 15x1, showing a tangent line G1 and a line Hr parallel to the horizontal line.

[0009] At least the following points become clear from the description of this specification and the accompanying drawings: Aspect 1 is an absorbent core forming device for manufacturing an absorbent core containing a superabsorbent polymer, comprising: a conveying section that conveys a base sheet in a conveying direction, a particle supplying section that supplies superabsorbent polymer particles toward the base sheet, and an adhesive discharging section that is arranged downstream of the particle supplying section in the conveying direction and discharges adhesive together with an air flow toward the base sheet, characterized in that the adhesive discharged from the adhesive discharging section pushes back, toward the base sheet, at least a portion of the superabsorbent polymer particles that have rebounded from the base sheet.

[0010] According to the absorbent core forming device of aspect 1, the discharged adhesive hits superabsorbent polymer (SAP) particles that have rebounded from the base sheet, causing the SAP particles to fall back onto the base sheet. Furthermore, the airflow discharged together with the adhesive can reduce the likelihood of the SAP particles being positioned in an unintended location. Furthermore, the adhesive entangles the rebounded SAP particles, thereby more reliably fixing the SAP particles.

[0011] Aspect 2 is the absorbent core forming apparatus according to Aspect 1, further comprising an upstream adhesive applicator that applies adhesive to the base sheet, located upstream of the particle supply unit in the conveying direction.

[0012] According to the absorbent core forming device of aspect 2, by applying adhesive in advance before the SAP particles are supplied, the amount of SAP particles bouncing off the base sheet can be reduced, thereby reducing the likelihood of the SAP particles being placed in unintended positions.

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

[0014] According to the absorbent core forming device of aspect 3, by suctioning from the back side of the base sheet using the suction section, the SAP particles are more likely to remain on the base sheet, and the amount of SAP particles bouncing off the base sheet can be reduced.

[0015] Aspect 4 is an absorbent core forming device described in any one of Aspects 1 to 3, in which when the adhesive discharging section is a first adhesive discharging section, a second adhesive discharging section that discharges adhesive toward the base sheet together with an air flow is provided downstream of the first adhesive discharging section in the conveying direction.

[0016] According to the absorbent core forming device of aspect 4, the rebound of SAP particles that cannot be pushed back by the adhesive discharged from the first adhesive dispensing section alone can be pushed back toward the base sheet by the adhesive discharged from the second adhesive dispensing section, thereby further reducing the amount of rebound and more reliably fixing the SAP particles.

[0017] Aspect 5 is an absorbent core forming device described in Aspect 4, in which the first adhesive discharging section and the second adhesive discharging section each have multiple rows of discharge outlets spaced apart in the conveying direction, each row having multiple discharge outlets arranged in a row.

[0018] According to the absorbent core forming device of aspect 5, the first adhesive discharging section and the second adhesive discharging section each have multiple discharge outlets, so that multiple rows of adhesive are applied in the conveying direction, thereby further reducing the rebound of SAP particles.

[0019] Aspect 6 is an absorbent core forming apparatus described in any one of aspects 1 to 5, wherein the conveying section has a conveying conveyor, and the conveying surface of the conveying conveyor is inclined with respect to the horizontal plane so that the downstream side in the conveying direction is lowered.

[0020] According to the absorbent core forming device of aspect 6, the downstream side of the conveying surface is inclined downward, making it easier for SAP particles that bounce off the base sheet to go downstream, thereby reducing the placement of SAP particles in unintended positions.

[0021] Aspect 7 is an absorbent core forming apparatus according to Aspect 6, in which the adhesive is ejected in a predetermined ejection direction from the ejection outlet of the adhesive ejection section, and when the angle at which the conveying surface is inclined with respect to the horizontal plane is θ0, the angle between the ejection direction and the horizontal plane is θ0 + 90 degrees or more.

[0022] According to the absorbent core forming device 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, making it easier to capture the SAP particles that bounce back.

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

[0024] According to the absorbent core forming device of aspect 8, by having not only a first adhesive discharging section but also a second adhesive discharging section, and by the second adhesive discharging section also discharging adhesive at such an angle, it becomes even easier to capture the rebounding SAP particles that could not be pushed back by the adhesive discharged from the first adhesive discharging section alone.

[0025] Aspect 9 is an absorbent core forming device described in Aspect 8, in which θ1 is the angle between the discharge direction of the first adhesive discharge section and the horizontal plane, and θ2 is the angle between the discharge direction of the second adhesive discharge section and the horizontal plane, and θ1 < θ2.

[0026] According to the absorbent core forming device of aspect 9, the SAP particles bounce back downstream, so the second adhesive discharging section, which is located downstream of the first adhesive discharging section, can discharge adhesive at a more inclined angle, making it easier to capture the SAP particles.

[0027] Aspect 10 is an absorbent core forming device described in any of aspects 1 to 5, in which the conveying section has a rotating body, the adhesive is discharged in a predetermined discharge direction from the discharge port of the adhesive discharge section, and the upstream side of the discharge direction is inclined toward the downstream side of the conveying direction so that the angle between an imaginary line extending the discharge direction and a tangent to the rotating body at the intersection of the imaginary line and the outer surface of the rotating body is greater than 90 degrees.

[0028] According to the absorbent core forming device of aspect 10, the adhesive discharge direction has such an inclination angle with respect to the outer peripheral surface of the rotating body, making it easier to capture SAP particles that have rebounded downstream in the conveyance direction.

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

[0030] According to the absorbent core forming device of aspect 11, by having not only a first adhesive discharging section but also a second adhesive discharging section, and by the second adhesive discharging section also discharging adhesive at such an angle, it becomes even easier to capture the rebounding SAP particles that could not be pushed back by the adhesive discharged from the first adhesive discharging section alone.

[0031] Aspect 12 is an absorbent core forming device described in Aspect 11, in which θ1 is the angle formed by a virtual line extended from the first adhesive discharging section and a tangent to the rotating body at the intersection of the virtual line and the outer peripheral surface of the rotating body, and θ2 is the angle formed by a virtual line extended from the second adhesive discharging section and a tangent to the rotating body at the intersection of the virtual line and the outer peripheral surface of the rotating body, and θ1 is < θ2.

[0032] According to the absorbent core forming device of aspect 12, the SAP particles bounce back downstream, so that the second adhesive discharging section, which is located downstream of the first adhesive discharging section, can discharge adhesive at a more inclined angle, making it easier to capture the SAP particles.

[0033] Aspect 13 is an absorbent core forming apparatus according to aspect 12, wherein the particle supply section supplies the superabsorbent polymer particles in a predetermined supply direction, and the angle between the supply direction and the conveying surface is less than 90 degrees.

[0034] According to the absorbent core forming device 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, thereby reducing the likelihood of the SAP particles being placed in unintended positions.

[0035] Aspect 14 is an absorbent core forming apparatus described in any of aspects 10 to 13, wherein the particle supply section supplies the superabsorbent polymer particles in a predetermined supply direction, and the angle formed by a supply imaginary line extending the supply direction and a tangent to the rotating body at the intersection of the supply imaginary line and the outer surface of the rotating body is less than 90 degrees.

[0036] According to the absorbent core forming device of aspect 14, supplying SAP particles at such an angle makes it easier for the particles to be supplied further downstream, thereby reducing the likelihood of superabsorbent polymer particles being placed in unintended locations.

[0037] Aspect 15 is a method for forming an absorbent core containing a superabsorbent polymer, comprising: a conveying step of conveying a base sheet in a conveying direction; a particle supplying step of supplying superabsorbent polymer particles toward the base sheet; and an adhesive discharging step of discharging adhesive together with an air flow toward the base sheet after the particle supplying step, wherein in the adhesive discharging step, the adhesive discharged in the adhesive discharging step pushes back toward the base sheet at least a portion of the superabsorbent polymer particles that have rebounded from the base sheet.

[0038] According to the method for forming an absorbent core of Aspect 15, the discharged adhesive hits the superabsorbent polymer particles that have rebounded from the base sheet during the particle supply step, causing the superabsorbent polymer particles to fall back onto the base sheet. In addition, the airflow discharged together with the adhesive can reduce the possibility of the superabsorbent polymer particles being disposed in an unintended position.

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

[0040] As used herein, "particles" when used in conjunction with the term "superabsorbent polymer (SAP)" encompass any discrete shape or form, and can include granules, agglomerates, flakes, fibers, spheres, and the like, and combinations thereof. Also, particles can have any desired shape, such as, for example, spherical, polygonal, rod-like, polyhedral, or other circular or angular regular or irregular shapes.

[0041] 1 is a schematic diagram illustrating a portion of an absorbent core forming apparatus 10 according to a first embodiment. The absorbent core forming apparatus 10 includes a conveying section 11 that conveys a base sheet 1K in a conveying direction, a particle supplying section 12 that supplies superabsorbent polymer particles toward the base sheet 1K, and an adhesive discharging section 15 that discharges adhesive toward the base sheet 1K together with an airflow. The adhesive discharging section 15 is located downstream of the particle supplying section 12 in the conveying direction. The absorbent core forming apparatus 10 according to this embodiment also includes two adhesive discharging sections 15: a first adhesive discharging section 15x1 and a second adhesive discharging section 15x2 that is located downstream of the first adhesive discharging section 15x1 in the conveying direction.

[0042] The base sheet 1K is a base material for the absorbent core, and superabsorbent polymer (SAP) particles are laminated on the base sheet 1K. The base sheet 1K may be any material capable of supporting the SAP particles, such as tissue, absorbent paper, or nonwoven fabric. The transport unit 11 includes a transport conveyor 11cn and multiple transport rollers 11rn. The transport rollers 11rn may be drive rollers driven to rotate by a drive source such as a motor, or may be driven rollers that rotate without a drive source. The transport conveyor 11cn is preferably a suction belt conveyor, with the upper surface of a rotating endless belt serving as the transport surface, which transports the base sheet 1K while suctioning it with multiple air intake holes (suction units described below) provided on the transport surface.

[0043] 2A and 2B are diagrams illustrating the supply of SAP particles and the discharge of adhesive in the first embodiment. As shown in FIGS. 1 and 2A , in the absorbent core forming device 10, first, a 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 traveling base sheet 1K (particle supplying step). Then, immediately after the particle supplying step, the adhesive discharge unit 15 (first adhesive discharge unit 15x1) discharges adhesive 15H toward the base sheet 1K together with an air flow (adhesive discharge step). The adhesive 15H is a hot-melt adhesive, and is discharged from multiple discharge ports (nozzles) of the adhesive discharge unit 15, as will be described in detail below.

[0044] After the first adhesive discharge section 15x1 discharges the adhesive 15H, the second adhesive discharge section 15x2, which is located downstream in the conveying direction from the first adhesive discharge section 15x1, further discharges the adhesive 15H toward the base sheet 1K together with the air flow.

[0045] The adhesive 15H is discharged together with an air flow, and 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, this is not limited to this, and each unit may have a different air pressure. Furthermore, the distance from the supply port of the particle supply unit 12 that supplies SAP particles to the conveying surface 11m of the 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 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 joins the discharged adhesive 15H so as to cover the SAP particles 12S, and the SAP particles 12S are cut to the desired size further downstream to form an absorbent core. In this embodiment, the SAP particles are supplied onto the base sheet 1K, and then the other sheet material 1S is laminated thereon. However, this is not limiting. For example, the absorbent core can be formed by simply laminating the SAP particles onto the base sheet 1K and then cutting the base sheet 1K to the desired size. Alternatively, the absorbent core can be formed by laminating the SAP particles onto the base sheet 1K and then laminating pulp fibers thereon. Furthermore, if another liquid-absorbent material, such as pulp fibers, is mixed in addition to the SAP particles as the material for the absorbent core, such a liquid-absorbent material can 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 SAP particles 12S are released to form a sheet containing SAP, the SAP particles 12S are typically supplied by gravity toward the conveying surface 11m or discharged together with pressurized air. The discharged SAP particles 12S tend to bounce back when they hit the conveying surface 11m (base sheet 1K) (see FIG. 2A ). In this embodiment, it is assumed that approximately 60% of the SAP particles 12S supplied at one time will bounce back. Furthermore, the released SAP particles 12S tend to bounce back in unintended directions, which could result in them scattering to places where they should not be placed.

[0048] In this regard, in the absorbent core forming device 10 of this embodiment, as shown in FIG. 2A , the adhesive 15H discharged from the adhesive discharge unit 15 can push back at least some of the SAP particles 12S that have rebounded from the base sheet 1K toward the base sheet 1K. Here, "pushing back" means moving the SAP particles 12S in the direction opposite to the conveyance direction and in the direction of gravity (vertically downward). In other words, the discharged adhesive 15H hits the SAP particles 12S that have rebounded from the base sheet 1K, causing the SAP particles 12S to fall back toward the base sheet 1K. Furthermore, the airflow discharged together with the adhesive 15H can reduce the possibility of the SAP particles 12S being positioned in an unintended position. Furthermore, the adhesive 15H entangles the rebounded SAP particles 12S, thereby more reliably fixing the SAP particles 12S.

[0049] Furthermore, in this embodiment, not only is the adhesive 15H discharged from the first adhesive discharge unit 15x1, but also the adhesive 15H is discharged from the second adhesive discharge unit 15x2, which is provided downstream in the conveyance direction from the first adhesive discharge unit 15x1. As a result, the SAP particles 12S that rebound cannot be fully pushed back by the adhesive 15H discharged from the first adhesive discharge unit 15x1 alone are pushed back toward the base sheet 1K by the adhesive 15H discharged from the second adhesive discharge unit 15x2, thereby further reducing the amount of rebound. This makes it possible to more reliably fix the SAP particles 12S.

[0050] Although the absorbent core forming device 10 of this embodiment has two adhesive dispensing units 15 (a first adhesive dispensing unit 15x1 and a second adhesive dispensing unit 15x2), the present invention is not limited to this. For example, if the amount of SAP particles 12S to be supplied is small, only the first adhesive dispensing unit 15x1 may be used. Furthermore, while the first adhesive dispensing unit 15x1 and the second adhesive dispensing unit 15x2 can push back rebounded SAP particles 12S, the first adhesive dispensing unit 15x1 can be designed with an emphasis on fixing the SAP particles 12S to the base sheet 1K, and the second adhesive dispensing unit 15x2 can be designed primarily for the purpose of improving or adjusting the adhesive strength of materials (such as the base sheet 1K).

[0051] In addition, in this embodiment, the first adhesive discharging unit 15x1 and the second adhesive discharging unit 15x2 are separated to increase the flexibility of each adhesive discharging unit 15, but the first adhesive discharging unit 15x1 and the second adhesive discharging unit 15x2 may be an integrated adhesive discharging unit. If the first adhesive discharging unit 15x1 and the second adhesive discharging unit 15x2 are installed as an integrated unit, costs can be reduced compared to installing separate devices, and maintenance of the device is also easier.

[0052] As described above, since the SAP particles 12S tend to bounce back when they are supplied from the particle supply unit 12, in this embodiment, as shown in Fig. 2B, the transport surface 11m of the transport conveyor 11cn is inclined with respect to the horizontal plane Hr so that the downstream side in the transport direction is lowered. This makes it easier for the SAP particles 12S that have bounced back from the base sheet 1K to move downstream due to gravity, thereby reducing the likelihood of the SAP particles 12S being placed in unintended positions.

[0053] 2B , the inclination angle θ0 with respect to the horizontal plane Hr is approximately 30 degrees. This is because the angle of repose of SAP particles (the maximum angle of the slope at which particles remain stable without collapsing when piled up) is 32 to 38 degrees, and the inclination angle is set to approximately this angle. Setting the inclination angle θ0 to approximately 30 degrees prevents the SAP particles 12S discharged from the particle supply unit 12 from rolling after landing on the conveyance surface 11m, and also makes them less likely to bounce back compared to when discharged onto a conveyance surface parallel to the horizontal plane. When the conveyance surface 11m of the transport conveyor 11cn is inclined downward on the downstream side, the inclination angle θ0 can be set up to approximately 75 degrees.

[0054] As described above, the conveying surface 11m is preferably inclined with respect to the horizontal plane Hr so that the downstream side in the conveying direction is downward, but this is not limiting. For example, the conveying surface 11m may be horizontal, or may be inclined with respect to the horizontal plane Hr so that the upstream side in the conveying direction is downward. Even if the conveying surface 11m is inclined so that the upstream side in the conveying direction is downward (i.e., so that the downstream side is upward), it is possible to similarly suppress the rebound of the SAP particles 12S if the conveyor 11cn is a suction belt conveyor and the suction force that sucks the base sheet 1K is strengthened. When the conveying surface 11m is inclined with respect to the horizontal plane Hr so that the upstream side in the conveying direction is downward, the inclination angle θ0 can be up to about 45 degrees, but is preferably up to about 30 degrees.

[0055] 2A and 2B , when the conveying surface 11m is inclined with respect to the horizontal plane Hr so that the downstream side is downward, and the inclination angle θ0 is 30 degrees, the distance L1 on the conveying surface 11m 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, and more preferably 25 mm. Similarly, the distance L2 on the conveying surface 11m 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, and more preferably 100 mm. Discharging the adhesive 15H from the first adhesive discharge portion 15x1 and the second adhesive discharge portion 15x2 within this range makes it easier for the adhesive 15H to be applied more effectively to the rebounded SAP particles 12S and to be entangled around the rebounded SAP particles 12S.

[0056] As shown in FIG. 2B , the adhesive 15H is discharged in a predetermined direction from the discharge ports (such as the discharge port 15t1 in FIG. 3 , which will be described later) of each adhesive discharge unit 15 (first adhesive discharge unit 15x1 and second adhesive discharge unit 15x2). Here, the "discharge direction" refers to the direction along the central axis of the discharge ports (15t1, 15t2) formed on the tip surface of the adhesive discharge unit 15. The central axis is a direction that passes through the center of gravity of the discharge port and is perpendicular to the tip surface. For example, if the discharge port is circular, the central axis is a straight line that passes through the center of the circle and is perpendicular to the plane of the circle. If the discharge port is rectangular, the central axis is a straight line that passes through the intersection of the diagonals of the rectangle and is perpendicular to the rectangular plane.

[0057] 2B , when the angle at which the conveying 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 unit 15x1 (adhesive discharge unit 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. In this way, the adhesive 15H can be discharged from the downstream side so as to cover the SAP particles 12S, compared to when the adhesive 15H is discharged perpendicular to the conveying surface 11m, and the SAP particles 12S that bounce back downstream can be more easily captured.

[0058] The second adhesive discharge unit 15x2, which is provided downstream of the first adhesive discharge unit 15x1 in the conveying direction, also discharges the adhesive 15H from a discharge port 15t2 in a predetermined discharge direction 15d2. Similarly, the angle θ2 between the discharge direction 15d2 of the second adhesive discharge unit 15x2 and the horizontal plane Hr is preferably θ0 + 90 degrees or greater. Discharging the adhesive 15H at such an angle from not only the first adhesive discharge unit 15x1 but also the second adhesive discharge unit 15x2 makes it easier to capture rebounding SAP particles 12S that could not be pushed back by the adhesive 15H discharged from the first adhesive discharge unit 15x1 alone.

[0059] Furthermore, in the absorbent core forming device 10 of this embodiment, it is preferable that the angle θ2 formed by the discharge direction 15d2 of the second adhesive discharge portion 15x2 and the horizontal plane Hr is larger than the angle θ1 formed by the discharge direction 15d1 of the first adhesive discharge portion 15x1 and the horizontal plane Hr (θ1<θ2). Because the SAP particles 12S bounce back toward the downstream side in the conveyance direction, by having the second adhesive discharge portion 15x2, which is arranged downstream of the first adhesive discharge portion 15x1, discharge the adhesive 15H at an angle that is inclined more toward the downstream side, the adhesive 15H of the second adhesive discharge portion 15x2 is more likely to be discharged from the downstream side toward the upstream side, making it easier to push back the SAP particles 12S that have fallen downstream.

[0060] As shown in FIGS. 2A and 2B , when the particle supply unit 12 supplies the SAP particles 12S toward the base sheet 1K, the particle supply unit 12 supplies the SAP particles 12S in a predetermined supply direction 12d. Similar to the discharge direction described above, the "supply direction" refers to a 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, if the supply port is circular, the central axis refers to a line passing through the center of the circle and perpendicular to the plane of the circle. If the supply port is rectangular, the central axis refers to a line passing through the intersection of the diagonals of the rectangle and perpendicular to the plane of the rectangle. The angle θ3 between the supply direction 12d of the SAP particles 12S and the conveying surface 11m is preferably less than 90 degrees. Supplying the SAP particles 12S so that θ3 is less than 90 degrees makes it easier for the SAP particles 12S to be supplied further downstream. This reduces the likelihood of the SAP particles 12S being disposed in an unintended position.

[0061] 1, the absorbent core forming device 10 may be provided with an upstream adhesive applicator 16 that applies adhesive to the base sheet 1K, upstream in the conveyance direction from the particle supply unit 12 that supplies the SAP particles 12S. By applying adhesive to the base sheet 1K in advance before the particle supply unit 12 supplies the SAP particles 12S to the base sheet 1K, the SAP particles 12S can be more easily attached to the base sheet 1K, and the amount of rebound of the SAP particles 12S can be reduced. This makes it possible to prevent the SAP particles 12S from being disposed in unintended positions.

[0062] Furthermore, as described above, if the transport conveyor 11cn is a suction belt conveyor having a plurality of air intake holes on its transport surface 11m that adsorbs and transports the base sheet 1K, the supplied SAP particles 12S also tend to remain on the base sheet 1K due to the air intake of the conveyor. Specifically, the SAP particles 12S are supplied to the front side of the base sheet 1K, but by providing a suction section 11P (air intake hole) that sucks the base sheet 1K on the back side of the base sheet 1K at the position where the SAP particles 12S are supplied, the suction of the suction section 11P makes it easier for the SAP particles 12S to stick to the base sheet 1K. This reduces the amount of SAP particles 12S that bounce back from the base sheet 1K. Note that a mesh belt may be used as the conveyor belt that is sucked by the suction section 11P.

[0063] 3 is a plan view of the surface of the adhesive discharge unit 15 (first adhesive discharge unit 15x1) on which the discharge ports 15t1 are provided. When the direction perpendicular to the conveyance direction is defined as the intersecting direction, as shown in FIG. 3, the discharge ports 15t1 of the adhesive discharge unit 15 are provided at intervals in the intersecting direction. Specifically, in this embodiment, five discharge ports 15t1 (15t2) are provided at intervals in the intersecting direction. When the row of the five discharge ports is defined as an outlet row 15R, the adhesive discharge unit 15 has two rows: an outlet row 15R1 on the upstream side in the conveyance direction and an outlet row 15R2 on the downstream side in the conveyance direction. In other words, the first adhesive discharge unit 15x1 and the second adhesive discharge unit 15x2 each have a plurality of outlet rows 15R, each of which has a plurality of outlets 15t1 (15t2) arranged in a row, spaced apart in the conveyance direction. Each outlet 15t1 (15t2) is composed of three nozzles. In other words, each outlet 15t1 (15t2) is composed of a set of three small outlets. Here, five outlets 15t1 are arranged in the cross direction in each outlet row 15R (15R1, 15R2), so the adhesive discharge unit 15 has a total of ten outlets 15t1. Since the first adhesive discharge unit 15x1 and the second adhesive discharge unit x2 each have multiple outlets 15t1 (15t2), multiple rows of adhesive 15H are applied in the conveyance direction, which further reduces rebound of SAP particles 12S.

[0064] In each ejection port array 15R, the distance L3 between adjacent ejection ports 15t1 in the cross direction is preferably about 5 mm. Also, the distance L4 in the transport direction between the ejection port 15t1 of the ejection port array 15R1 and the ejection port 15t1 of the ejection port array 15R2 is preferably about 3.5 mm. In the ejection outlet array 15R1, the ejection outlet 15t1 located at the farthest side in the intersecting direction is designated as ejection outlet 15t1a, the ejection outlet 15t1 adjacent to ejection outlet 15t1a on the other side in the intersecting direction is designated as ejection outlet 15t1b, and in the ejection outlet array 15R2, the ejection outlet 15t1 located at the farthest side in the intersecting direction is designated as ejection outlet 15t1c, and the ejection outlet 15t1 adjacent to ejection outlet 15t1c on the other side in the intersecting direction is designated as ejection outlet 15t1d. In the intersecting direction, the ejection outlet 15t1c does not overlap with the ejection outlets 15t1a and 15t1b, but is located between the ejection outlets 15t1a and 15t1b. Similarly, the ejection outlet 15t1b does not overlap with the ejection outlets 15t1c and 15t1d, but is located between the ejection outlets 15t1c and 15t1d. By arranging the adhesive 15H in this manner, when the adhesive 15H is ejected, the adhesive 15H is applied in a mesh-like pattern in the cross direction with a surface and degree of airiness, reducing the failure to capture rebounded SAP particles and making it easier for the adhesive 15H to become entangled with more SAP particles.

[0065] Furthermore, each outlet 15t1 (15t2) has three nozzles, and of the three nozzles, the adhesive 15H ejected from the middle nozzle is preferably ejected so as to fall straight down, while the adhesives 15H ejected from the left and right nozzles are preferably ejected in a direction that pushes back the rebounded SAP particles toward the base sheet 1K, and more preferably, are ejected at an angle toward the outside in the intersecting direction. This makes it easier for the adhesive 15H to be ejected in a planar or net-like shape, and to become entangled with more SAP particles.

[0066] Second Embodiment Next, an absorbent core forming apparatus 10 according to a second embodiment will be described with reference to Figures 4, 5A, and 5B. Figure 4 is a schematic diagram showing a portion of the absorbent core forming apparatus 10 according to the second embodiment. Figures 5A and 5B are diagrams illustrating the supply of SAP particles and the discharge of adhesive according to 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 in the first embodiment, except that in the second embodiment, the conveying section 11' that conveys the base sheet 1K in the conveying direction has a rotating body 11tn instead of the conveying conveyor 11cn. In the following description of the second embodiment, the same components as in the first embodiment are denoted by the same reference numerals, and descriptions of parts common to the first embodiment will be omitted.

[0068] As shown in Figures 4 and 5A, in the absorbent core forming device 10 of the second embodiment, the base sheet 1K is transported in contact with the outer surface 11n of a rotor 11tn rotating in the transport direction (transport process), and as in the first embodiment, the particle supply unit 12 supplies SAP particles 12S toward the surface of the base sheet 1K (particle supply process), and immediately after the particle supply process, the first adhesive discharge unit 15x1 (adhesive discharge unit 15) discharges adhesive 15H together with the air flow, and further downstream, the second adhesive discharge unit 15x2 discharges adhesive 15H together with the air flow toward the base sheet 1K (adhesive discharge process).

[0069] The rotor 11tn preferably has a plurality of air intake holes (not shown) on its circumferential surface and is provided with a suction mechanism (suction unit) that sucks and holds the base sheet 1K by sucking the base sheet 1K toward the inner periphery of the rotor 11tn through the air intake holes, thereby making it easier for the SAP particles 12S to remain on the base sheet 1K.

[0070] 5A and 5B , in the second embodiment, the adhesive 15H is also discharged in a predetermined discharge direction from the discharge port of each adhesive discharge unit 15 (the first adhesive discharge unit 15x1 and the second adhesive discharge unit 15x2). Specifically, in the first adhesive discharge unit 15x1, the adhesive 15H is discharged in a predetermined discharge direction 15d1 from the discharge port 15t1 of the first adhesive discharge unit 15x1, 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 an imaginary line V1 extending from the discharge direction 15d1 and a tangent line G1 to the rotating body 11tn at an intersection P1 between the imaginary line V1 and the outer peripheral surface 11n of the rotating body 11tn is greater than 90 degrees. Since some of the supplied SAP particles 12S bounce back downstream in the conveying direction, ejecting the adhesive 15H from the downstream side so as to cover the SAP particles 12S makes it easier to push back the SAP particles 12S that have bounced back downstream, rather than ejecting the adhesive 15H perpendicularly to the outer surface 11n.

[0071] In the second embodiment, a second adhesive discharge unit 15x2 is also provided downstream of the first adhesive discharge unit 15x1 in the conveyance direction. Similar to the first adhesive discharge unit 15x1, the second adhesive discharge unit 15x2 discharges adhesive 15H from a discharge port 15t2 in a predetermined discharge direction 15d2. The discharge direction 15d2 is inclined such that the angle θ2 formed by an imaginary line V2 extending from the discharge direction 15d2 of the second adhesive discharge unit 15x2 and a tangent G2 to the rotating body 11tn at an intersection P2 between the imaginary line V2 and the outer peripheral surface 11tn of the rotating body 11tn is greater than 90 degrees ( FIG. 5B ). In the absorbent core forming device 10, adhesive 15H is ejected at such an angle not only from the first adhesive ejection section 15x1 but also from the second adhesive ejection section 15x2, making it easier to capture the rebounding SAP particles 12S that could not be pushed back by the adhesive 15H ejected from the first adhesive ejection section 15x1 alone.

[0072] Note that the angle θ2 formed by the virtual line V2 extended from the second adhesive discharge portion 15x2 and the tangent G2 to the rotating body 11tn at the intersection P2 of the virtual line V2 and the outer peripheral surface 11n of the rotating body 11tn is preferably larger than the angle θ1 formed by the virtual line V1 extended from the first adhesive discharge portion 15x1 and the tangent G1 to the rotating body 11tn at the intersection P1 of the virtual line V1 and the outer peripheral surface 11n of the rotating body 11tn (θ1<θ2). Because the supplied SAP particles 12S tend to bounce downstream in the conveyance direction, the second adhesive discharge portion 15x2, which is disposed downstream of the first adhesive discharge portion 15x1, discharges the adhesive 15H at a more inclined angle, thereby more easily capturing the SAP particles 12S that have fallen downstream.

[0073] 6 is a diagram illustrating the tangent line G1 and the line Hr parallel to the horizontal line. In the first embodiment, the conveying surface 11m of the conveyor 11cn was inclined relative to the horizontal plane Hr so that the downstream side in the conveying direction was inclined downward. In the second embodiment, the discharge direction 15d1 of the first adhesive discharge unit 15x1 is preferably set based on a similar principle. Specifically, as shown in FIG. 6, the intersection point P1 is the point where an imaginary line V1, which is an extension of the discharge direction 15d1 of the first adhesive discharge unit 15x1, intersects with the outer peripheral surface 11n of the rotating body 11tn. When the angle θ4 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, the discharge direction 15d1 of the first adhesive discharge unit 15x1 is preferably set so that θ4 is approximately 30 degrees. This makes it easier for the adhesive 15H discharged from the adhesive discharge portion 15x1 to push back the SAP particles 12S that have rebounded from the base sheet 1K toward the base sheet 1K.

[0074] 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, and the angle θ3 formed by a supply imaginary line V3 extending from the supply direction 12d and a tangent G3 to the rotor 11tn at an intersection P3 between the supply imaginary line V3 and the outer peripheral surface 11n of the rotor 11tn is preferably less than 90 degrees. This causes the upstream side of the supply direction 12d to be inclined toward the upstream side of the conveying direction, and the downstream side of the supply direction 12d to face the downstream side of the conveying direction, making it easier for the SAP particles 12S to flow downstream. As a result, it is possible to reduce the likelihood of the SAP particles 12S being disposed in unintended positions.

[0075] In the second embodiment, the SAP particle supply position of the particle supply unit 12 is the uppermost position of the rotor 11tn as shown in Fig. 4, but is not limited to this. The supply position of the SAP particles 12S can be, for example, up to a position shifted 30 degrees upstream or 60 degrees downstream from a line connecting the uppermost position and the center of the rotor 11tn. Preferably, the supply position is within a range of up to a position shifted 20 degrees upstream or 10 degrees downstream, and more preferably, the SAP particles are supplied from directly above the uppermost position of the rotor 11tn (i.e., θ3 is 90 degrees).

[0076] 4, the absorbent core forming device 10 of this embodiment may also be provided with an upstream adhesive applicator 16 that applies adhesive to the base sheet 1K, upstream in the conveyance direction from the particle supply unit 12 that supplies the SAP particles 12S. By applying adhesive to the base sheet 1K in advance before the SAP particles 12S are supplied, the SAP particles 12S become more easily attached to the base sheet 1K and the amount of rebound of the SAP particles 12S from the base sheet 1K can be reduced. This makes it possible to prevent the SAP particles 12S from being disposed in unintended positions.

[0077] ===Other=== The above embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof.

[0078] In the first and second embodiments described above, the discharge direction 15d1 of the first adhesive discharge section 15x1 is set so that the upstream side of the discharge direction 15d1 is inclined toward the downstream side of the conveyance direction. However, this is not limited to this. Conversely, the upstream side of the discharge direction 15d1 may be inclined toward the upstream side of the conveyance direction. FIG. 7 illustrates a modified example of the discharge direction 15d1 of the first adhesive discharge section 15x1. In the modified example shown in FIG. 7, the discharge direction 15d1 (solid line) of the first adhesive discharge section 15x1 is set so that the upstream side of the discharge direction 15d1 is inclined toward the upstream side of the conveyance direction. In this case, the inclination range of the discharge direction 15d1 is preferably such that the angle θ5 between the perpendicular line Ve and the discharge direction 15d1 is between 0 degrees and approximately 20 degrees, based on the line Ve perpendicular to the conveyance surface 11m of the conveyor 11cn or the outer circumferential surface 11n of the rotating body 11tn.

[0079] 7, the discharge direction 15d1 is shown by a dotted line when the upstream side of the discharge direction 15d1 is inclined toward the downstream side of the conveyance direction. In this case, the angle θ6 between the vertical line Ve and the discharge direction 15d1 is preferably in the range of 0 to approximately 20 degrees. When the angles θ5 and θ6 are in the above-mentioned range, the rebounded SAP particles can be effectively pushed back toward the base sheet 1K. Similarly, the discharge direction 15d2 of the second adhesive discharge section 15x2 may also be set so that the upstream side of the discharge direction 15d2 is inclined toward the upstream side of the conveyance direction.

[0080] 1K Base sheet 1S Another sheet material 10 Absorbent core forming device 11 Conveying section, 11' Conveying section 11cn Conveying conveyor 11m Conveying surface 11n Outer circumferential surface 11P Suction section 11rn Conveying roller 11tn Rotating body 12 Particle supply section 12d Supply direction 12S Super absorbent polymer (SAP) particles 15 Adhesive discharge section 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 port 15t2 Discharge port 15x1 First adhesive discharge section 15x2 Second adhesive discharge section 16 Upstream adhesive application section

Claims

1. 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 together with an air flow toward the base sheet, wherein the adhesive discharge unit pushes 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.

2. The absorbent core forming apparatus according to claim 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.

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 that suctions 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.

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 that discharges an adhesive together with an air flow toward the base sheet is provided downstream of the first adhesive discharge unit in the conveying direction.

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 line and are spaced apart from each other in the conveying direction.

6. The absorbent core forming apparatus according to claim 1 or 2, wherein the conveying unit has 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.

7. The absorbent core forming apparatus according to claim 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 conveyance 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. An absorbent core forming apparatus characterized by this.

8. The absorbent core forming apparatus according to claim 7, 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 conveyance 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. An absorbent core forming apparatus characterized by this.

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

10. The absorbent core forming apparatus according to claim 1 or 2, wherein the conveyance unit has a rotating body, the adhesive is discharged from the discharge port of the adhesive discharge unit in a predetermined discharge direction, and the upstream side in the discharge direction is inclined to the downstream side in the conveyance direction so that 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. An absorbent core forming apparatus characterized by this.

11. The absorbent core forming apparatus according to claim 10, 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 conveyance direction. The second adhesive discharge unit discharges the adhesive from the discharge port in a predetermined discharge direction, and the upstream side in the discharge direction of the second adhesive discharge unit is inclined to 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 unit 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. An absorbent core forming apparatus characterized by this.

12. The absorbent core forming apparatus according to claim 11, wherein an angle θ1 is formed between a virtual line obtained by extending the first adhesive discharge portion and a tangent to the rotating body at an intersection of the virtual line and the outer peripheral surface of the rotating body, and an angle θ2 is formed between a virtual line obtained by extending the second adhesive discharge portion and a tangent to the rotating body at an intersection of the virtual line and the outer peripheral surface of the rotating body, and θ1 < θ2. The absorbent core forming apparatus is characterized by this.

13. The absorbent core forming apparatus according to claim 6, wherein the particle supply portion supplies the superabsorbent polymer particles in a predetermined supply direction, and an angle formed between the supply direction and the transport surface is less than 90 degrees. The absorbent core forming apparatus is characterized by this.

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

15. A method for forming an absorbent core containing a superabsorbent polymer, comprising: a transport step of transporting a base sheet in a transport 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. A method for forming an absorbent core is characterized by this.

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