JP7782382B2 - Absorbent article manufacturing method and absorbent article manufacturing device - Google Patents

Description

The present invention relates to a method and apparatus for manufacturing absorbent articles.

Absorbent articles that absorb liquids such as urine and bodily fluids are known (for example, Patent Document 1).

JP 2019-97871 A

Absorbent articles have an absorbent core. The absorbent core is manufactured by pressing a lower absorbent material and an upper absorbent material. If the lower absorbent material and the upper absorbent material are misaligned when pressed, it may be impossible to manufacture the desired absorbent core. The present invention aims to prevent misalignment when the lower absorbent material and the upper absorbent material are pressed.

The present invention is a method for manufacturing an absorbent article having an absorbent core in which a lower-layer absorbent material and an upper-layer absorbent material are laminated, and includes a first forming step of forming the lower-layer absorbent material on the surface of a rotatable first forming drum, a second forming step of forming the upper-layer absorbent material on the surface of a rotatable second forming drum, a pressing step of pressing the lower-layer absorbent material peeled from the surface of the first forming drum and the upper-layer absorbent material peeled from the surface of the second forming drum, and a blowing step of blowing air onto at least one of the lower-layer absorbent material and the upper-layer absorbent material before the lower-layer absorbent material and the upper-layer absorbent material are pressed in the pressing step.

This invention prevents misalignment of the upper and lower absorbent layers when they are pressed.

FIG. 1 is a plan view of an absorbent pad according to an embodiment. FIG. 2 is an exploded perspective view of the absorbent pad according to the embodiment. FIG. 3 is a diagram showing the internal structure of the absorbent pad according to the embodiment. FIG. 4 is a flowchart of a process for manufacturing an absorbent core of an absorbent pad according to an embodiment. FIG. 5 is a diagram showing an example of an apparatus for manufacturing an absorbent pad. FIG. 6(A) is a perspective view showing a part of the upper-layer absorbent mat, and FIG. 6(B) is a side view showing a part of the upper-layer absorbent mat.

Embodiments of the present invention will be described below with reference to the drawings. Note that the configurations of the following embodiments are examples, and the present invention is not limited to the configurations of these embodiments.

<Embodiment>
In this embodiment, the longitudinal direction of a replaceable absorbent pad (an example of an "absorbent article" in this application) is the direction connecting the front body portion, which faces the wearer's abdomen, and the back body portion, which faces the back. A crotch section, which is positioned between the front body portion (one side in the longitudinal direction) and the back body portion (the other side in the longitudinal direction) and faces the wearer's crotch, is located adjacent to the front body portion (one side in the longitudinal direction) and the back body portion (the other side in the longitudinal direction) (in the longitudinal center). Furthermore, when the absorbent pad is worn by a wearer (hereinafter abbreviated as "worn state"), the side facing the wearer's skin (the inner side when worn) is the skin-facing side, and the side opposite the skin-facing side (the outer side when worn) is the non-skin-facing side. Furthermore, the direction connecting the skin-facing side and the non-skin-facing side is the thickness direction, and the direction perpendicular to both the longitudinal direction and the thickness direction is the width direction. Additionally, a view from the thickness direction is a planar view.

Figure 1 is a plan view of an absorbent pad according to this embodiment. The absorbent pad 1 comprises a crotch region 1B, which corresponds to the crotch area covering the wearer's genitals when worn; a front body region 1F, located on the abdominal side of the crotch region 1B and corresponding to the wearer's front body and waist; and a back body region 1R, located on the back side of the crotch region 1B and corresponding to the wearer's back body and waist. An absorbent body is incorporated centered around the crotch region 1B. At the ends of the front body region 1F and the back body region 1R, in the absorbent body-free portions in the short and long directions of the absorbent pad, all sheets covering the absorbent body are adhered with a hot melt adhesive or the like, preventing the inflow of bodily fluids from non-adhesive portions and regulating the position of the absorbent body. The absorbent pad 1 is worn between the underwear and the skin, providing close contact with the wearer's skin. Furthermore, if this absorbent pad 1 is worn inside a tape-type diaper or pants-type diaper, the absorbent pad 1 will absorb the discharged liquid, so even if the wearer discharges liquid, only the absorbent pad 1 needs to be replaced and the diaper itself can be reused.

The absorbent pad 1 also has elastic bodies 2L, 2R in areas surrounding the wearer's legs (thighs) to prevent the formation of gaps between the absorbent pad 1 and the wearer's skin that could serve as a liquid outflow path. The elastic bodies 2L, 2R extend in the longitudinal direction of the absorbent pad 1. Elastic bodies 3BL, 3BR are attached to the ends of side sheets 8L, 8R, a pair of side sheets that extend more inward in the skin-facing width direction of the absorbent pad 1 than the elastic bodies 2L, 2R, at the center ends in the width direction of the absorbent pad 1. When worn, the side sheets 8L, 8R rise due to the force of the elastic bodies 3BL, 3BR, and become three-dimensional gathers 3L, 3R. The absorbent pad 1 conforms to the wearer's body shape due to the force of the elastics 2L, 2R, which function as leg gathers, and adheres closely to the wearer's skin due to the three-dimensional gathers 3L, 3R that are raised by the force of the elastics 3BL, 3BR, so that bodily fluids excreted by the wearer are absorbed by the absorbent body of the absorbent pad 1 without leaking from the absorbent pad 1. Note that elastic materials that make up the elastics 2L, 2R and elastics 3BL, 3BR can be selected appropriately from rubber threads, band-shaped rubber, etc. The elastics 2L, 2R, 3BL, 3BR may also be multiple parallel rubber threads.

Figure 2 is an exploded perspective view of the absorbent pad according to this embodiment. The absorbent pad 1 comprises side sheets 8L, 8R forming three-dimensional gathers 3L, 3R, a top sheet 7, a back sheet 5, an absorbent body 6, and a cover sheet 4 comprising elastic bodies 2L, 2R, which are layered in this order from the skin-facing side to the non-skin-facing side. The absorbent body 6 is absent at the front and back body ends of the absorbent pad 1, and all sheets are bonded together. The absorbent body 6 may be rectangular. The sheets may be bonded together using methods such as hot-melt adhesive or ultrasonic welding. The top sheet 7 is an example of a skin-facing sheet in this disclosure, and the back sheet 5 is an example of a non-skin-facing sheet in this disclosure.

The cover sheet 4 is a durable sheet that forms the exterior surface of the absorbent pad 1 and facilitates maintaining the overall shape of the absorbent pad 1. The cover sheet 4 is typically a nonwoven fabric made of synthetic fibers such as polypropylene, polyethylene, or polyethylene terephthalate. The cover sheet 4 may be liquid-permeable or liquid-impermeable. Alternatively, a liquid-impermeable nonwoven fabric may be perforated in multiple locations to provide breathability. While the cover sheet 4 is present in this embodiment, the back sheet 5, described below, may also have a shape-maintaining effect, and the cover sheet 4 may be omitted. The back sheet 5 is a liquid-impermeable sheet. For example, the back sheet 5 is a film sheet made of a thermoplastic liquid-impermeable resin such as polyethylene film to prevent leakage of discharged liquid. The back sheet 5 is moisture-permeable and gas-permeable, i.e., gas-permeable, to prevent stuffiness when worn.

The top sheet 7 is placed on the wearer's skin side so as to cover the absorbent surface of the absorbent body 6. It is made of a spunbond nonwoven fabric containing thermoplastic resin fibers, an air-through nonwoven fabric, or the like. This top sheet 7 is liquid permeable in part or in whole. Therefore, when the absorbent pad 1 is placed, bodily fluids released by the wearer pass through the top sheet 7, which may come into contact with the wearer's skin, into the absorbent body 6, and are absorbed there. The top sheet 7 may also be hydrophilic. The longitudinal direction of the absorbent pad 1 is the same as the longitudinal direction of the absorbent body 6 and the top sheet 7.

The back sheet 5, absorbent body 6, and top sheet 7 all extend from the front body region 1F to the back body region 1R. Therefore, when the wearer's genitals are covered with the cover sheet 4, which is made up of the back sheet 5, absorbent body 6, and top sheet 7 laminated together, the longitudinal ends of the back sheet 5, absorbent body 6, and top sheet 7 are located on the wearer's ventral and dorsal sides. In other words, the wearer's genitals are covered by the absorbent body 6 from the ventral to dorsal sides. Therefore, whether the wearer is lying supine or prone, excreted fluid comes into contact with the absorbent body 6 via the top sheet 7.

The side sheets 8L, 8R are made of a moisture-permeable, but water-impermeable nonwoven fabric. As mentioned above, the side sheets 8L, 8R adhere closely to the skin as three-dimensional gathers 3L, 3R. Therefore, exudates that come into contact with the side sheets 8L, 8R do not leak further in the width direction of the absorbent pad 1, and the moisture contained in the exudates is gradually absorbed by the absorbent body 6. The top sheet 7 is made of a hydrophilic nonwoven fabric that feels pleasant against the skin. It directly receives bodily fluids by coming into contact with the skin and gradually absorbs them into the absorbent body 6. It also prevents backflow of bodily fluids already absorbed by the absorbent body 6. The elastic bodies 2L, 2R are provided at the widthwise ends of the absorbent pad 1, and the contractile force of the elastic bodies 2L, 2R urges the absorbent pad 1 to conform to the wearer's body shape. In other words, the elastic bodies 2L, 2R function as side gathers.

Figure 3 shows the internal structure of the absorbent pad according to this embodiment. Specifically, it is a cross-sectional view of the absorbent pad 1 of Figure 1 taken along line A-A. The absorbent pad 1 has an absorbent body 6 wrapped in a top sheet 7 provided on the skin-facing side of the absorbent body 6, side sheets 8L and 8R provided on the lateral sides of the absorbent body 6, and a back sheet 5 provided on the non-skin-facing side of the absorbent body 6. The absorbent body 6 has an absorbent core 6C and a core wrap sheet 6W that wraps around the absorbent core 6C. The top sheet 7 and the side sheets 8L and 8R are joined at both skin-facing end portions of the top sheet 7, and the side sheets 8L and 8R and the back sheet 5 are joined on the non-skin-facing side. In this way, the sheets that wrap around the absorbent body 6 are joined together to form a bag-like space, so the absorbent body 6 does not escape from this bag-like space.

The absorbent body 6 has a structure in which granular absorbent resin such as SAP (Super Absorbent Polymer), a hydrophilic polymer with a crosslinked structure capable of absorbing and retaining water, is held in the gaps between, for example, short fibers of cellulosic fibers such as pulp fibers, rayon fibers, or cotton fibers, or short fibers obtained by hydrophilizing synthetic fibers such as polyethylene, polypropylene, or polyethylene terephthalate. Therefore, in the absorbent body 6, the volumetric change of the absorbent resin before and after absorbing liquid basically occurs within the short fibers that hold the absorbent resin in the gaps. Therefore, when viewed from the perspective of the entire absorbent body 6, it can be said that the expansion rate of the thickness of the absorbent body 6 after absorbing liquid is not as large as the expansion rate of the absorbent resin itself.

In this disclosure, SAP particles refer to a granular resin composition containing SAP. The term "SAP-containing resin composition" as used herein encompasses both compositions consisting solely of SAP and compositions containing SAP as the main component, with other substances added to the extent that they do not adversely affect water absorption. Examples of "other substances" include additives (such as surface modifiers added to hydrophobize the particle surface) and unreacted monomers remaining during the synthesis of SAP.

The absorbent core 6C of the absorbent pad 1 according to this embodiment is formed by stacking multiple absorbent mats. Specifically, the absorbent core 6C includes an upper absorbent mat 6a that faces the wearer's skin and a lower absorbent mat 6b that faces away from the wearer's skin. The upper and lower absorbent mats 6a and 6b are stacked such that their stacking surfaces face each other. The stacking surface of the upper absorbent mat 6a is perpendicular to the thickness direction of the upper absorbent mat 6a and faces away from the wearer's skin. The stacking surface of the lower absorbent mat 6b is perpendicular to the thickness direction of the lower absorbent mat 6b and faces toward the wearer's skin. Therefore, the stacking surface of the upper absorbent mat 6a faces the lower absorbent mat 6b, and the stacking surface of the lower absorbent mat 6b faces the upper absorbent mat 6a. The upper absorbent mat 6a is an example of an upper absorbent material in this disclosure, and the lower absorbent mat 6b is an example of a lower absorbent material in this disclosure.

The upper absorbent mat 6a may be formed from a mixture of pulp fibers and SAP particles. In this case, when discharged liquid flows into the upper absorbent mat 6a from the top sheet 7 side, the discharged liquid is absorbed by the SAP particles contained in the upper absorbent mat 6a, and the discharged liquid can be fixed. The lower absorbent mat 6b may be formed from a mixture of pulp fibers and SAP particles. The lower absorbent mat 6b may also be designed so as not to include SAP particles. If it does not contain SAP particles, the lower absorbent mat 6b is formed by molding pulp fibers.

The upper absorbent mat 6a may have a width equal to or greater than the lower absorbent mat 6b across the entire longitudinal area of the absorbent body 6. The lower absorbent mat 6b may have a width equal to or greater than the upper absorbent mat 6a across the entire longitudinal area of the absorbent body 6. For example, the upper absorbent mat 6a may be hourglass-shaped, and the lower absorbent mat 6b may be approximately rectangular. The area of the absorbent body 6 where the most discharged liquid flows in is the widthwise center. By making the absorbent core 6C a multi-layer structure in this area, discharged liquid can be absorbed efficiently.

The crotch region 1B is sandwiched between the wearer's legs, so compressive pressure is applied inward in the width direction. Meanwhile, the front body region 1F and back body region 1R are subjected to pressure in the thickness direction of the absorbent body 6 due to the weight of the wearer. To accommodate these pressures, the crotch region 1B of the upper-layer absorbent mat 6a is provided with a constriction.

SAP particles can absorb and fix discharged liquid, but it takes a certain amount of time to absorb the discharged liquid. The lower absorbent mat 6b temporarily holds and diffuses the discharged liquid that the upper absorbent mat 6a was unable to absorb, allowing the discharged liquid to be absorbed over a wider area of the upper absorbent mat 6a. When SAP particles absorb water and expand, this can block the flow path of the discharged liquid, a phenomenon known as core blocking. However, the lower absorbent mat 6b contains only a small amount of SAP particles, allowing the discharged liquid to move relatively easily within the lower absorbent mat 6b. For this reason, the lower absorbent mat 6b has higher liquid diffusion properties than the upper absorbent mat 6a, and functions as a diffusion layer for the discharged liquid.

The absorbent core 6C has SAP layers 11L and 11R disposed between the upper and lower absorbent mats 6a and 6b. The SAP layers 11L and 11R are formed by a collection of multiple SAP particles. As shown in FIG. 3, the SAP layer 11L is disposed on the left side of the absorbent core 6C, and the SAP layer 11R is disposed on the right side of the absorbent core 6C. The SAP layers 11L and 11R may be rectangular, elliptical, or other polygonal in plan view. By providing the SAP layers 11L and 11R between the upper and lower absorbent mats 6a and 6b, the absorbent core 6C can increase its overall absorption capacity of discharged liquid. Alternatively, SAP particles can be dispersed in the widthwise center between the upper and lower absorbent mats 6a and 6b to form an SAP layer having the SAP layers 11L and 11R.

The SAP layers 11L, 11R are formed, for example, by scattering SAP particles onto the lower absorbent mat 6b during the manufacturing process of the absorbent core 6C. The SAP layers 11L, 11R are sandwiched between the upper absorbent mat 6a and the lower absorbent mat 6b. Therefore, even if the absorbent pad 1 moves due to the wearer's movements, the SAP particles contained in the SAP layers 11L, 11R are prevented from moving. Alternatively, an adhesive may be applied to the surface of the lower absorbent mat 6b to adhere the SAP particles to the surface of the lower absorbent mat 6b.

The core wrap sheet 6W is a thin, liquid-permeable sheet. By wrapping the absorbent core 6C with the core wrap sheet 6W, the SAP in the absorbent core 6C described above is less likely to become contaminated with other structures. It also prevents the absorbent core 6C from losing its shape. The core wrap sheet 6W can be formed from nonwoven fabric or pulp fiber, with tissue paper being an example of pulp fiber. The absorbent body 6 is wrapped in the back sheet 5 and top sheet 7, which also help prevent the absorbent core 6 from losing its shape. Therefore, a configuration without the core wrap sheet 6W is also possible. In the configuration shown in Figure 3, the core wrap sheet 6W is composed of two sheets: an upper-layer core wrap sheet 6Wa and a lower-layer core wrap sheet 6Wb. The upper-layer core wrap sheet 6Wa covers the top sheet 7 side, which is the skin-facing side of the absorbent core 6C, and the lower-layer core wrap sheet 6Wb covers the back sheet 5 side, which is the non-skin-facing side of the absorbent core 6C, and the side of the absorbent core 6C. The upper core wrap sheet 6Wa and the lower core wrap sheet 6Wb are laminated and bonded to each other at both widthwise ends of the skin-facing side of the absorbent core 6C. Therefore, the skin-facing side of the absorbent body 6 is made up of the upper core wrap sheet 6Wa, and the side and non-skin-facing sides of the absorbent body 6 are made up of the lower core wrap sheet 6Wb.

The lower core wrap sheet 6Wb and the back sheet 5 are bonded together with multiple adhesives HM, such as hot melt, applied in a roughly linear pattern along the longitudinal direction of the absorbent pad 1, forming a bonded region. When viewed from the width direction, the adhesive HM is applied intermittently to form multiple spaced-apart bonded sections. Between the bonded sections, non-adhesive regions where no adhesive HM is applied are formed, roughly linearly when viewed from the longitudinal direction. Discharged liquid that penetrates between the lower core wrap sheet 6Wb and the back sheet 5 is retained in the non-adhesive regions. When the core wrap sheet is composed of two sheets, the upper core wrap sheet 6Wa and the lower core wrap sheet 6Wb may be made of the same material. The upper core wrap sheet 6Wa and the lower core wrap sheet 6Wb may be, for example, tissue paper. Alternatively, the upper core wrap sheet 6Wa and the lower core wrap sheet 6Wb may be made of different materials.

Next, a manufacturing method of the absorbent pad 1 according to this embodiment will be described. The manufacturing method of the absorbent pad 1 according to this embodiment is characterized by the process of manufacturing the absorbent core 6C, and therefore, the process of manufacturing the absorbent core 6C will be described below. FIG. 4 is a flowchart of the process of manufacturing the absorbent core 6C according to this embodiment. First, in step S101, a first forming process is carried out to form the lower absorbent mat 6b. In step S102, a first blowing process is carried out to blow air onto the lower absorbent mat 6b. In step S103, a spraying process is carried out to spray SAP particles onto the layered surface of the lower absorbent mat 6b. By spraying the SAP particles onto the layered surface of the lower absorbent mat 6b, SAP layers 11L, 11R are formed on the layered surface of the lower absorbent mat 6b.

In step S104, a second forming process is carried out to form the upper absorbent mat 6a. In step S105, a second blowing process is carried out to blow air onto the upper absorbent mat 6a. In step S106, a pressing process is carried out to press the upper absorbent mat 6a and the lower absorbent mat 6b together with the stacked surfaces of the upper absorbent mat 6a and the lower absorbent mat 6b overlapping each other. The absorbent pad 1 is manufactured using the absorbent core 6C produced by pressing the upper absorbent mat 6a and the lower absorbent mat 6b.

In the manufacturing method of the absorbent pad 1 according to this embodiment, the first and second spraying steps are performed before the upper and lower absorbent mats 6a, 6b are pressed in the pressing step. This is not limiting, and in the manufacturing method of the absorbent pad 1 according to this embodiment, at least one of the first and second spraying steps may be performed before the upper and lower absorbent mats 6a, 6b are pressed in the pressing step.

In step S102, when air is blown onto the layered surface of the lower absorbent mat 6b, the layered surface of the lower absorbent mat 6b becomes rough, and the lower absorbent mat 6b becomes bulky. Roughening the layered surface of the lower absorbent mat 6b increases the interlocking force between the lower absorbent mat 6b and the SAP layers 11L and 11R. Furthermore, in step S105, when air is blown onto the layered surface of the upper absorbent mat 6a, the layered surface of the upper absorbent mat 6a becomes rough, and the upper absorbent mat 6a becomes bulky. Roughening the layered surface of the upper absorbent mat 6a increases the interlocking force between the upper absorbent mat 6a and the SAP layers 11L and 11R. By increasing the interlocking force between at least one of the upper absorbent mat 6a and the lower absorbent mat 6b and the SAP layers 11L and 11R, the movement of SAP particles contained in the SAP layers 11L and 11R is further suppressed during the manufacturing process of the absorbent pad 1. When the manufactured absorbent pad 1 is worn by a wearer and the absorbent pad 1 moves due to the wearer's movements, the movement of the SAP particles contained in the SAP layers 11L and 11R is further suppressed.

For example, if the stacking surfaces of the upper and lower absorbent mats 6a and 6b are not rough, there is a possibility that the upper and lower absorbent mats 6a and 6b will become misaligned when they are pressed. If misalignment occurs when the upper and lower absorbent mats 6a and 6b are pressed, the desired absorbent core 6C cannot be manufactured, discharged liquid may leak from the absorbent core 6C, and the comfort of wearing the absorbent pad 1 may be impaired. If at least one of the stacking surfaces of the upper and lower absorbent mats 6a and 6b becomes rough, the fibers of the upper and lower absorbent mats 6a and 6b will be more likely to entangle when they are stacked together. This increases the fitting force between the upper and lower absorbent mats 6a and 6b, preventing misalignment of the upper and lower absorbent mats 6a and 6b when they are pressed, making it possible to manufacture the desired absorbent core 6C. Misalignment of the upper and lower absorbent mats 6a and 6b is also prevented after the absorbent pad 1 has been manufactured. Preventing misalignment of the upper and lower absorbent mats 6a and 6b prevents leakage of exudate from the absorbent core 6C, improving the comfort of wearing the absorbent pad 1. Furthermore, the rate at which exudate moves from the upper and lower absorbent mats 6a to 6b increases, and the amount of exudate that moves increases.

Next, with reference to Figure 5, a manufacturing method of the absorbent pad 1 according to this embodiment will be described in more detail. Figure 5 is a diagram showing an example of an apparatus 30 for manufacturing the absorbent pad 1. The manufacturing apparatus 30 used in the manufacturing method of the absorbent pad 1 includes a conveying path 31, a forming device 32, an air blowing device 33, an SAP spraying device 34, a forming device 35, an air blowing device 36, and a pressing device 37. The forming device 32 includes a forming drum 41 and a supplying device 42. The forming device 35 includes a forming drum 43 and a supplying device 44. The pressing device 37 includes a first roller 45 and a second roller 46. Note that not all of the components of the manufacturing apparatus 30 shown in Figure 5 are essential, and components of the manufacturing apparatus 30 may be added or deleted as appropriate.

The transport path 31 is a conveyor that transports the upper absorbent mat 6a and the lower absorbent mat 6b in a predetermined direction. The forming device 32 is a device that forms the lower absorbent mat 6b on the surface of the forming drum 41. The forming drum 41 is a rotating body that can rotate in the direction of arrow R1. The supply device 42 supplies fibers (hereinafter referred to as lower fiber) for forming the lower absorbent mat 6b to the surface (outer peripheral surface) of the forming drum 41. A molding die is provided on the surface of the forming drum 41 for forming the lower fiber into a predetermined shape. The lower absorbent mat 6b is formed on the surface of the forming drum 41 by supplying the lower fiber to the molding die on the surface of the forming drum 41. The surface of the forming drum 41 may be provided with one molding die or multiple molding dies. Multiple molding dies may be provided on the surface of the forming drum 41 so that multiple molding dies are lined up circumferentially around the forming drum 41.

The forming drum 41 has a built-in suction mechanism that sucks the lower absorbent mat 6b formed on the surface of the forming drum 41. As the forming drum 41 rotates, suction by the suction mechanism is stopped when the lower absorbent mat 6b formed on the surface of the forming drum 41 moves near the transport path 31. This causes the lower absorbent mat 6b to peel off from the surface of the forming drum 41 and move from the forming drum 41 to the transport path 31. In other words, the lower absorbent mat 6b is transferred from the forming drum 41 to the transport path 31. In this way, a peeling process is performed in which the lower absorbent mat 6b is peeled off from the surface of the forming drum 41. The peeling process in which the lower absorbent mat 6b is peeled off from the surface of the forming drum 41 is an example of a first peeling process.

The air blowing device 33 blows air onto the lower absorbent mat 6b. The air blowing device 33 may be an air blower (air supply device) having a tank for storing air and a nozzle for blowing the air stored in the tank onto the lower absorbent mat 6b. The position at which the air is blown may be variable or fixed. The air blowing device 33 may be capable of blowing air onto multiple positions. The air blowing device 33 may blow air onto the lower absorbent mat 6b for a predetermined period from before the peeling process of the lower absorbent mat 6b begins until the peeling process of the lower absorbent mat 6b ends.

The air blowing device 33 may blow air onto the layered surface of the lower absorbent mat 6b while the peeling process of the lower absorbent mat 6b is being performed. In this case, the air blowing device 33 may blow air between the lower absorbent mat 6b and the surface of the forming drum 41. Specifically, air is blown between the layered surface of the lower absorbent mat 6b and the surface of the forming drum 41. The air blowing device 33 may blow air in the direction opposite to the rotation direction of the forming drum 41 (direction of arrow R1). The air blowing device 33 may blow air onto the end of the lower absorbent mat 6b downstream of the rotation direction of the forming drum 41 by blowing air from downstream to upstream in the rotation direction of the forming drum 41. This applies a force to the lower absorbent mat 6b in a direction different from the force that peels the lower absorbent mat 6b from the surface of the forming drum 41 toward the conveying path 31. As a result, the lower absorbent mat 6b is more likely to peel off from the surface of the forming drum 41 at the end of the lower absorbent mat 6b downstream in the rotation direction of the forming drum 41.

The air blowing device 33 may blow air onto the layered surface of the lower absorbent mat 6b after the peeling process of the lower absorbent mat 6b has been completed. The air blowing device 33 may blow air onto the layered surface of the lower absorbent mat 6b while the conveying process of conveying the lower absorbent mat 6b peeled from the surface of the forming drum 41 is being performed. For example, the air blowing device 33 may blow air onto the layered surface of the lower absorbent mat 6b for a predetermined period of time between the start of conveyance of the lower absorbent mat 6b and the time the lower absorbent mat 6b is conveyed below the SAP sprayer 34. The air blowing device 33 may blow air onto the layered surface of the lower absorbent mat 6b while the peeling process of the lower absorbent mat 6b is being performed, and may blow air again onto the layered surface of the lower absorbent mat 6b after the peeling process of the lower absorbent mat 6b has been completed. The amount of air blown onto the layered surface of the lower absorbent mat 6b while the peeling process of the lower absorbent mat 6b is being performed may be the same as or different from the amount of air blown onto the layered surface of the lower absorbent mat 6b after the peeling process of the lower absorbent mat 6b has been performed.

The lower absorbent mat 6b is transported below the SAP sprayer 34. The SAP sprayer 34 sprays SAP particles onto the layered surface of the lower absorbent mat 6b, forming SAP layers 11L and 11R on the layered surface of the lower absorbent mat 6b. After the air blowing process onto the layered surface of the lower absorbent mat 6b is performed, the SAP sprayer 34 performs a spraying process of SAP particles, thereby forming SAP layers 11L and 11R on the layered surface of the lower absorbent mat 6b. Because the layered surface of the lower absorbent mat 6b is roughened by the air blowing process onto the layered surface of the lower absorbent mat 6b, the movement of the SAP particles contained in the SAP layers 11L and 11R is further suppressed.

The SAP sprayer 34 may spray SAP particles onto the area of the laminated surface of the lower absorbent mat 6b onto which air has been blown. When air is blown onto the entire laminated surface of the lower absorbent mat 6b, the SAP sprayer 34 may spray SAP particles onto the entire laminated surface of the lower absorbent mat 6b. When air is blown onto a partial area of the laminated surface of the lower absorbent mat 6b, the SAP sprayer 34 may spray SAP particles onto a partial area of the laminated surface of the lower absorbent mat 6b.

The forming device 35 is a device that forms the upper layer absorbent mat 6a on the surface of the forming drum 43. The forming drum 43 is a rotating body that can rotate in the direction of arrow R2. The supply device 44 supplies fibers (hereinafter referred to as upper layer fibers) for forming the upper layer absorbent mat 6a to the surface (outer peripheral surface) of the forming drum 43. A molding die for molding the upper layer fibers into a predetermined shape is provided on the surface of the forming drum 43, and the upper layer absorbent mat 6a is formed on the surface of the forming drum 43 by supplying the upper layer fibers to the molding die on the surface of the forming drum 43. The surface of the forming drum 43 may be provided with one molding die or multiple molding dies. Multiple molding dies may be provided on the surface of the forming drum 43 so that multiple molding dies are lined up in the circumferential direction of the forming drum 43.

The forming drum 43 has a built-in suction mechanism that sucks the upper absorbent mat 6a formed on the surface of the forming drum 43. The lower absorbent mat 6b is transported below the forming drum 43, and as the forming drum 43 rotates, the upper absorbent mat 6a formed on the surface of the forming drum 43 moves above the lower absorbent mat 6b, at which point suction by the suction mechanism is stopped. This causes the upper absorbent mat 6a to peel off from the surface of the forming drum 43, and the upper absorbent mat 6a moves from the forming drum 43 to the conveying path 31 with the layered surface of the upper absorbent mat 6a and the layered surface of the lower absorbent mat 6b overlapping. In other words, the upper absorbent mat 6a is transferred from the forming drum 43 to the conveying path 31. In this way, a peeling process is performed in which the upper absorbent mat 6a is peeled off from the surface of the forming drum 43. The peeling process in which the upper absorbent mat 6a is peeled off from the surface of the forming drum 43 is an example of a second peeling process.

The air blowing device 36 blows air onto the upper absorbent mat 6a. The air blowing device 36 may be an air blower (air supply device) having a tank for storing air and a nozzle for blowing the air stored in the tank onto the upper absorbent mat 6a. The position at which the air is blown may be variable or fixed. The air blowing device 36 may be capable of blowing air onto multiple positions. The air blowing device 36 may blow air onto the upper absorbent mat 6a for a predetermined period from before the peeling process of the upper absorbent mat 6a begins until the peeling process of the upper absorbent mat 6a ends.

The air blowing device 36 may blow air onto the upper absorbent mat 6a while the peeling process of the upper absorbent mat 6a is being performed. The air blowing device 36 may blow air between the upper absorbent mat 6a and the surface of the forming drum 43 while the peeling process of the upper absorbent mat 6a is being performed. Specifically, air is blown between the surface opposite the stacked surface of the upper absorbent mat 6a and the surface of the forming drum 43. The air blowing device 36 may blow air in the direction opposite to the rotation direction of the forming drum 43 (the direction of arrow R2). The air blowing device 36 may blow air onto the end of the upper absorbent mat 6a downstream of the rotation direction of the forming drum 43 by blowing air from downstream to upstream in the rotation direction of the forming drum 43. This applies a force to the upper absorbent mat 6a in a direction different from the force that peels the upper absorbent mat 6a from the surface of the forming drum 43 toward the conveying path 31. As a result, the upper absorbent mat 6a is more likely to peel off from the surface of the forming drum 43 at the end of the upper absorbent mat 6a downstream in the rotation direction of the forming drum 43.

The air blowing device 36 may blow air onto the layered surface of the upper absorbent mat 6a for a predetermined period of time from before the peeling process of the upper absorbent mat 6a begins until the peeling process of the upper absorbent mat 6a ends. The amount of air blown between the upper absorbent mat 6a and the surface of the forming drum 43 may be the same as or different from the amount of air blown onto the layered surface of the upper absorbent mat 6a.

The upper and lower absorbent mats 6a and 6b are transported to the press device 37. The press device 37 presses the lower absorbent mat 6b peeled from the surface of the forming drum 41 and the upper absorbent mat 6a peeled from the surface of the forming drum 43. The press device 37 presses the upper and lower absorbent mats 6a and 6b with the stacked surfaces of the upper and lower absorbent mats 6a and 6b overlapping. The first roller 45 is a rotating body that can rotate in the direction of arrow R3. The second roller 46 is a rotating body that can rotate in the direction of arrow R4. As the first roller 45 and the second roller 46 rotate, the upper and lower absorbent mats 6a and 6b are pressed by the first roller 45 and the second roller 46. As a result, the upper and lower absorbent mats 6a and 6b are pressed with the stacked surfaces of the upper and lower absorbent mats 6a and 6b overlapping. As described above, by roughening at least one of the stacking surfaces of the upper absorbent mat 6a and the lower absorbent mat 6b, misalignment of the upper absorbent mat 6a and the lower absorbent mat 6b when they are pressed is prevented.

A plurality of lower absorbent mats 6b may be formed in a continuous state on the surface of the forming drum 41, and a plurality of upper absorbent mats 6a may be formed in a continuous state on the surface of the forming drum 43. In this case, the upper absorbent mats 6a and lower absorbent mats 6b are pressed together and then cut to a predetermined size to produce a plurality of absorbent cores 6C. Alternatively, the upper absorbent mats 6a and lower absorbent mats 6b may be cut to a predetermined size and then pressed together.

Alternatively, multiple lower absorbent mats 6b may be formed discontinuously on the surface of the forming drum 41, and multiple upper absorbent mats 6a may be formed discontinuously on the surface of the forming drum 43. This makes it possible to omit the process of cutting the upper absorbent mats 6a and lower absorbent mats 6b. By forming multiple lower absorbent mats 6b discontinuously on the surface of the forming drum 41, each of the multiple lower absorbent mats 6b can be easily peeled off from the surface of the forming drum 41. By forming multiple upper absorbent mats 6a discontinuously on the surface of the forming drum 43, each of the multiple upper absorbent mats 6a can be easily peeled off from the surface of the forming drum 43.

The forming device 32, forming drum 41, and supply device 42 located upstream of the conveying path 31 may be referred to as the first forming device, first forming drum, and first supply device. The forming device 35, forming drum 43, and supply device 44 located downstream of the conveying path 31 may be referred to as the second forming device, second forming drum, and second supply device.

Next, the mold provided on the surface of the forming drum 43 will be described. For example, a mold for forming the upper-layer absorbent mat 6a shown in FIG. 6 may be provided on the surface of the forming drum 43. FIG. 6(A) is a perspective view showing a portion of the upper-layer absorbent mat 6a, and FIG. 6(B) is a side view showing a portion of the upper-layer absorbent mat 6a. FIGS. 6(A) and 6(B) show one of both longitudinal ends of the upper-layer absorbent mat 6a. One of both longitudinal ends of the upper-layer absorbent mat 6a is the end of the upper-layer absorbent mat 6a downstream in the direction of rotation of the forming drum 43. The configuration of the other of both longitudinal ends of the upper-layer absorbent mat 6a may be the same as the configuration of one of both longitudinal ends of the upper-layer absorbent mat 6a. The configuration of the upper-layer absorbent mat 6a shown in FIGS. 6(A) and 6(B) can also be applied to the lower-layer absorbent mat 6b. Therefore, a mold for forming a lower absorbent mat 6b having a configuration similar to the upper absorbent mat 6a shown in Figures 6(A) and (B) may be provided on the surface of the forming drum 41.

One of the longitudinal ends of the upper absorbent mat 6a has a first portion 21, which is a pillar portion (thick portion), and a second portion 22, which is a recessed portion recessed further than the first portion 21 toward the longitudinal center of the upper absorbent mat 6a. One of the longitudinal ends of the upper absorbent mat 6a may have both the first portion 21 and the second portion 22, or both longitudinal ends of the upper absorbent mat 6a may have both the first portion 21 and the second portion 22. The second portion 22 is a thin portion that is thinner than the first portion 21. As shown in Figures 6(A) and (B) , the second portion 22 has a gradient portion (gradient shape) that gradually becomes thinner toward the longitudinal end of the upper absorbent mat 6a. When the upper absorbent mat 6a is formed on the surface of the forming drum 43, the thickness of the second portion 22 gradually becomes thinner toward the downstream side in the rotation direction of the forming drum 43. The sloped surface of the second portion 22 may be curved or inclined. The sloped surface of the second portion 22 is continuous with the surface opposite the stacked surface of the upper absorbent mat 6a and is also continuous with the side of the end of the upper absorbent mat 6a.

The first portion 21 and the second portion 22 are adjacent to each other along the width direction of the upper absorbent mat 6a. In Figures 6(A) and 6(B), multiple first portions 21 and multiple second portions 22 are arranged so that they are alternately adjacent to each other along the width direction of the upper absorbent mat 6a. Therefore, multiple first portions 21 are arranged intermittently along the width direction of the upper absorbent mat 6a, and multiple second portions 22 are arranged intermittently along the width direction of the upper absorbent mat 6a. One first portion 21 and one second portion 22 may be arranged so that they are adjacent to each other along the width direction of the upper absorbent mat 6a.

A forming die having grooves and protrusions corresponding to the shapes of the first portion 21 and the second portion 22 is provided on the surface of the forming drum 43. By supplying upper layer fibers to the forming die provided on the surface of the forming drum 43, an upper layer absorbent mat 6a having the first portion 21 and the second portion 22 is formed on the surface of the forming drum 43.

The second portion 22 is recessed more toward the center of the upper absorbent mat 6a in the longitudinal direction than the first portion 21. Therefore, when air is blown toward the end of the upper absorbent mat 6a downstream in the rotation direction of the forming drum 43, air easily enters between the upper absorbent mat 6a and the surface of the forming drum 43 from the second portion 22. This causes a force to be applied to the upper absorbent mat 6a in a direction different from the force that pulls the upper absorbent mat 6a from the surface of the forming drum 43 toward the conveying path 31. As a result, the upper absorbent mat 6a is easily peeled from the surface of the forming drum 43 at the end of the upper absorbent mat 6a downstream in the rotation direction of the forming drum 43.

Providing the first portion 21 at the end of the upper absorbent mat 6a prevents the second portion 22 from tearing when the upper absorbent mat 6a is peeled off from the surface of the forming drum 43. Providing the first portion 21 at the end of the upper absorbent mat 6a makes it possible to control the flow direction of the air blown onto the end of the upper absorbent mat 6a, allowing the air to flow in a concentrated manner between the upper absorbent mat 6a and the surface of the forming drum 43.

The second portion 22 has a slope that gradually becomes thinner toward the longitudinal end of the upper absorbent mat 6a. The second portion 22 is adjacent to the first portion 21 and functions as a support that supports the first portion 21. By making the sloped surface of the second portion 22 a curved or inclined surface, air can more easily enter between the upper absorbent mat 6a and the surface of the forming drum 43 from the second portion 22.

The shape of the second portion 22 is not limited to that shown in Figures 6(A) and (B), and the second portion 22 may have other shapes. The sloped surface of the second portion 22 may be continuous with the surface opposite the stacked surface of the upper-layer absorbent mat 6a, and may also be continuous with the stacked surface of the upper-layer absorbent mat 6a. The second portion 22 may have a stepped portion (stepped shape) that gradually becomes thinner toward the longitudinal end of the upper-layer absorbent mat 6a.

<Variations>
A modified example of this embodiment will now be described. The air blowing device 33 and the air blowing device 36 may be integrated. For example, an air blowing device having the configuration of the air blowing device 33 and the configuration of the air blowing device 36 may blow air onto at least one of the upper absorbent mat 6a and the lower absorbent mat 6b. Furthermore, the air blowing device 33 may blow air onto at least one of the upper absorbent mat 6a and the lower absorbent mat 6b, or the air blowing device 36 may blow air onto at least one of the upper absorbent mat 6a and the lower absorbent mat 6b.

The present embodiment has been described above, but the present invention is not limited to the above embodiment. In the above embodiment, an absorbent pad was used as an example, but the present invention is not limited to this and can also be applied to absorbent articles such as tape-type disposable diapers and pants-type disposable diapers.

The features contained in the embodiments and variations disclosed above can be combined with each other.

1..Absorbent pad 1B..Crotch region 1F..Front body region 1R..Back body region 2L, 2R..Elastic bodies 3BL, 3BR..Elastic bodies 3L, 3R..3D gathers 4..Cover sheet 5..Back sheet 6..Absorbent body 6C..Absorbent core 6a..Upper layer absorbent mat 6b..Lower layer absorbent mat 6W..Core wrap sheet 6Wa..Upper layer core wrap sheet 6Wb..Lower layer core wrap sheet 7 Top sheets 8L, 8R, side sheets HM, hot melt 11L, 11R, SAP layer 21, first portion 22, second portion 30, manufacturing device 31, conveying paths 32, 35, forming devices 33, 36, air blowing device 34, SAP spraying device 37, pressing devices 41, 43, forming drums 42, 44, supply device 45, first roller 46, second roller

Claims (13)

A method for manufacturing an absorbent article having an absorbent core in which a lower-layer absorbent material and an upper-layer absorbent material are laminated, comprising:
a first forming step of forming the lower layer absorbent material on a surface of a rotatable first forming drum;
a second forming step of forming the upper layer absorbent material on a surface of a rotatable second forming drum;
a pressing step of pressing the lower-layer absorbent material peeled off from the surface of the first forming drum and the upper-layer absorbent material peeled off from the surface of the second forming drum;
a blowing step of blowing air onto at least one of the lower-layer absorbent material and the upper-layer absorbent material from outside the first forming drum and the second forming drum before the lower-layer absorbent material and the upper-layer absorbent material are pressed in the pressing step;
A method for manufacturing an absorbent article comprising the steps of: a first peeling step of peeling the lower-layer absorbent material from the surface of the first forming drum,
the blowing step includes blowing air between the lower-layer absorbent material and the surface of the first forming drum while the first peeling step is being performed.
A method for manufacturing the absorbent article according to claim 1. the blowing step includes blowing air onto an end of the lower-layer absorbent material on the downstream side in the rotation direction of the first forming drum by flowing air from the downstream side to the upstream side in the rotation direction of the first forming drum.
A method for manufacturing the absorbent article according to claim 2. the end portion of the lower-layer absorbent material on the downstream side in the rotation direction of the first forming drum has a first portion and a second portion that is thinner than the thickness of the first portion of the end portion of the lower-layer absorbent material,
a thickness of the second portion of the end portion of the lower-layer absorbent material gradually decreasing toward the downstream side in the rotation direction of the first forming drum;
A method for manufacturing an absorbent article according to claim 3. a plurality of the lower-layer absorbent materials are formed in a discontinuous state on the surface of the first forming drum;
A method for manufacturing the absorbent article according to claim 2. a second peeling step of peeling the upper-layer absorbent material from the surface of the second forming drum,
the blowing step includes blowing air between the upper layer absorbent material and the surface of the second forming drum while the second peeling step is being performed.
A method for manufacturing the absorbent article according to claim 1. the blowing step includes blowing air onto an end of the upper-layer absorbent material on the downstream side in the rotation direction of the second forming drum by flowing air from the downstream side to the upstream side in the rotation direction of the second forming drum.
The method for manufacturing the absorbent article according to claim 6. the end portion of the upper-layer absorbent material on the downstream side in the rotation direction of the second forming drum has a first portion and a second portion that is thinner than the thickness of the first portion of the end portion of the upper-layer absorbent material,
a thickness of the second portion of the end portion of the upper-layer absorbent material gradually decreasing toward the downstream side in the rotation direction of the second forming drum;
A method for manufacturing an absorbent article according to claim 7. a plurality of the upper-layer absorbent materials are formed in a discontinuous state on the surface of the second forming drum;
The method for manufacturing the absorbent article according to claim 6. the pressing step includes pressing the lower-layer absorbent material and the upper-layer absorbent material together in a state where the stacking surfaces of the lower-layer absorbent material and the upper-layer absorbent material are superimposed on each other;
the blowing step includes blowing air onto at least one of the stacking surface of the lower-layer absorbent material and the stacking surface of the upper-layer absorbent material.
A method for manufacturing the absorbent article according to any one of claims 1 to 9. a spraying step of spraying particles of SAP, which is a superabsorbent polymer, onto the layered surface of the lower-layer absorbent material peeled off from the surface of the first forming drum,
The spraying step is carried out after air is blown onto the layered surface of the lower-layer absorbent material.
The method for manufacturing an absorbent article according to claim 10. a conveying step of conveying the lower-layer absorbent material peeled off from the surface of the first forming drum,
the blowing step includes blowing air onto the layered surface of the lower-layer absorbent material while the conveying step is being performed.
The method for manufacturing an absorbent article according to claim 10. An apparatus for manufacturing an absorbent article having an absorbent core in which a lower-layer absorbent material and an upper-layer absorbent material are laminated,
a first forming device for forming the lower layer absorbent material on a surface of a rotatable first forming drum;
a second forming device that forms the upper layer absorbent material on a surface of a rotatable second forming drum;
a press device that presses the lower-layer absorbent material peeled off from the surface of the first forming drum and the upper-layer absorbent material peeled off from the surface of the second forming drum;
a blowing device that blows air onto at least one of the lower-layer absorbent material and the upper-layer absorbent material from outside the first forming drum and the second forming drum before the lower-layer absorbent material and the upper-layer absorbent material are pressed by the press device;
An absorbent article manufacturing apparatus comprising: