Liquid application method, absorbent article manufacturing method using the same, and absorbent article manufacturing device

Abstract

To provide techniques of enabling a liquid to adhere to a material with a prescribed adhesion width.SOLUTION: A liquid adhesion method comprises dispersing a liquid from a liquid-dispersing apparatus to a material made of a textile material transported by a transportation apparatus in a constant direction, thereby causing the liquid to adhere to the material. The liquid-dispersing apparatus has a nozzle for spraying the liquid. The method comprises adjusting a liquid adhesion width by setting a direction of the nozzle spreading the liquid to an angle in an oblique direction relative to the width direction of the material.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a liquid application method, a method for manufacturing an absorbent article using the same, and an apparatus for manufacturing an absorbent article. [Background technology]

[0002] Conventionally, absorbent articles such as disposable diapers, incontinence pads, sanitary products, etc. are known. In general, absorbent articles are formed into a thin sheet-like, mat-like, or other shape and include an absorbent body that absorbs bodily fluids discharged by a wearer. Patent Document 1 describes a method for manufacturing an absorbent article that includes an absorbent body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-213855 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a manufacturing process of an absorbent article, materials used in the absorbent article are transported by a transport device. The manufacturing process of an absorbent article may include a step of applying liquid to the materials being transported by the transport device. In order to achieve a required function in the absorbent article, it is necessary to apply liquid to the materials with a predetermined application width. However, no specific proposal has been made regarding a method of applying liquid.

[0005] An object of the present invention is to provide a technique capable of depositing liquid onto a material with a predetermined deposition width. [Means for solving the problem]

[0006] In order to solve the above problems, in the present invention, the direction in which the liquid is spread from the nozzle is set to be oblique to the width direction of the material.

[0007] In detail, the present invention is a liquid application method for applying liquid to a material made of a fibrous material transported in a fixed direction by a transport device by spraying the liquid from a liquid spraying device onto the material, the liquid spraying device having a nozzle for spraying the liquid, and including adjusting the width of liquid application by setting the direction of diffusion of the liquid by the nozzle at an angle that is oblique to the width direction of the material.

[0008] In the above liquid deposition method, the spray width of the liquid may be adjusted by setting the spray pressure of the nozzle according to the transport speed of the transport device, and the deposition width may be adjusted by setting the angle of the diffusion direction according to the spray width.

[0009] In the above liquid application method, a groove extending along the transport direction of the material is formed in the center of the width direction of the material, and the liquid spraying device has a plurality of nozzles, the plurality of nozzles including a first nozzle that sprays the liquid toward one end side of the groove in the width direction, and a second nozzle that sprays the liquid toward the other end side of the groove in the width direction, and the application width may be adjusted by setting the angles of the first nozzle and the second nozzle.

[0010] In the above liquid depositing method, the deposition width may be adjusted by tilting the first nozzle and the second nozzle outward in the width direction with respect to a vertical direction.

[0011] In the above liquid applying method, the application width may be adjusted by tilting the material outward in the width direction with respect to the vertical direction.

[0012] The present invention can also be understood from the aspect of a method for manufacturing an absorbent article. For example, the present invention may be a method for manufacturing an absorbent article, which includes a liquid applying step of applying a liquid to the material used in the absorbent article by using the liquid applying method.

[0013] The present invention can also be seen from the aspect of an absorbent article manufacturing apparatus. For example, the present invention may be an absorbent article manufacturing apparatus including a conveying device that conveys a material made of a fibrous material in a certain direction, and a liquid spraying device having a nozzle that sprays a liquid and sprays the liquid toward the material on the conveying device, and the nozzle may be set at an angle such that the diffusion direction of the liquid is oblique to the width direction of the material. Effect of the Invention

[0014] According to the present invention, liquid can be applied to a material with a predetermined application width. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a flow chart outlining a liquid deposition method. [Diagram 2] FIG. 2 is a diagram (part 1) showing an example of an apparatus for manufacturing absorbent articles. [Diagram 3] FIG. 3 is a diagram (part 2) showing an example of an apparatus for manufacturing absorbent articles. [Figure 4] FIG. 4 is a flow chart outlining the liquid application method. [Diagram 5] FIG. 5 is a diagram showing an example of an apparatus for manufacturing absorbent articles. [Figure 6] FIG. 6 is a diagram showing an example of an apparatus for manufacturing absorbent articles. [Figure 7] FIG. 7 is a diagram showing an example of an apparatus for manufacturing absorbent articles. [Figure 8] FIG. 8 is a plan view of the absorbent pad. [Figure 9] FIG. 9 is a cross-sectional view of the absorbent pad when cut in the width direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the configurations of the following embodiments are merely examples, and the present invention is not limited to the configurations of these embodiments.

[0017] <Embodiment> A liquid attachment method according to an embodiment will be described. In this embodiment, a material made of a fiber material is used for the absorbent body of the absorbent article. Examples of the fiber material include short fibers of cellulosic fibers such as pulp fibers, rayon fibers, or cotton fibers, and short fibers of synthetic fibers such as polyethylene, polypropylene, or polyethylene terephthalate that have been hydrophilized. The material is formed in a sheet shape and is cut to a predetermined size to be used as an absorbent body. A liquid is attached to this material while it is being transported by a transport device before being cut. The liquid is, for example, water or a chemical solution. For example, when particles of super absorbent polymer (SAP) are to be spread on the material, a liquid such as water or a chemical solution is attached to the material in a step before the step of spreading the SAP particles in order to hold the SAP particles on the material. Since the SAP particle group is held on the material by the water attached to the material, the SAP particles can be arranged in an appropriate position. In addition, a chemical solution such as a skin care agent or an antibacterial agent may be attached to the material in order to improve the wearing comfort of the absorbent article.

[0018] In order to achieve the required functions in absorbent articles, liquid must be applied to the material at a certain width. The width is measured in the cross direction (CD) perpendicular to the longitudinal direction (MD) of the material. is the width of the liquid deposit in the direction

[0019] The liquid attachment method according to the present embodiment is a method for attaching liquid to materials conveyed in a fixed direction by a conveying device by spraying the liquid from a liquid spraying device. The liquid spraying device has a nozzle for spraying liquid toward the material being conveyed. It is desirable that the liquid is attached to the material at a predetermined attachment width in the design of the material. For example, when attaching liquid to a material to hold SAP particles on the material, if the attachment width of the liquid is narrower than the arrangement width of the SAP particles, it becomes impossible to hold all of the SAP particles on the material. Also, when attaching a medicinal liquid such as a skin care agent or an antibacterial agent to the material, it becomes impossible to attach the medicinal liquid to a necessary area, and therefore the effect of the medicinal liquid cannot be obtained sufficiently.

[0020] Therefore, in the liquid application method according to this embodiment, the liquid application width is adjusted by setting the direction in which the liquid is spread by the nozzle of the liquid spraying device at an angle that is oblique to the width direction of the material. With the liquid application method according to this embodiment, it is possible to apply liquid to the material at a predetermined application width without the need to replace the nozzle.

[0021] FIG. 1 is a flow chart showing an outline of the liquid adhering method according to the present embodiment. In the liquid adhering step according to the present embodiment, the liquid adhering width is adjusted by setting the liquid spreading direction by the nozzle at an angle oblique to the width direction of the material (step S101). The liquid spraying device sprays the liquid in an elliptical cone shape with the nozzle outlet as the apex. The bottom of the elliptical cone is the liquid adhering range on the material, and the long axis direction of the ellipse that is the bottom is the liquid spreading direction by the nozzle. In the liquid adhering method according to the present embodiment, the nozzle is rotated to set the liquid spreading direction by the nozzle at an angle oblique to the width direction of the material. This makes it possible to adjust the liquid spreading width by setting the liquid spreading direction by the nozzle at an angle oblique to the width direction of the material.

[0022] Next, the liquid adhering method according to the present embodiment will be described in more detail with reference to Figs. 2 and 3. Figs. 2 and 3 are diagrams showing an example of an absorbent article manufacturing apparatus used in the absorbent article manufacturing method using the liquid adhering method according to the present embodiment. Fig. 2 shows a state seen from the lateral direction with respect to the conveying direction, and Fig. 3 shows a state seen from above vertically with respect to the conveying direction. The present manufacturing apparatus M used for manufacturing absorbent articles includes a conveying line M1 (an example of the "conveying device" in the present application) and a liquid spraying device M2. The conveying line M1 is a conveyor that conveys a material A, which is a so-called continuous sheet, in a certain direction (the direction of the right-pointing arrow that is the "conveying direction (MD)" in the figure). The material A is made of a fibrous material, and is used as an absorbent body of an absorbent article by being cut to a predetermined size. The liquid spraying device M2 has a nozzle N that sprays the liquid L toward the material A, and sprays the liquid L on the material A on the conveying line M1. The liquid L is attached to the material A by being sprayed toward the material A. The spray pressure of the nozzle N is adjusted to 0.01 MPa to 0.5 MPa so that a predetermined amount of liquid is applied in accordance with the conveying speed of the material A.

[0023] The liquid spraying device M2 sprays the liquid L in an elliptical cone shape with the nozzle of the nozzle N as the apex. In FIG. 3, the bottom surface of the elliptical cone is illustrated, and the ellipse shown by the solid line indicates the spray range of the liquid L when the liquid diffusion direction by the nozzle N is set at an angle oblique to the width direction (CD direction) of the material A. The major axis W1 of this solid line ellipse is the spray width of the liquid L to the material A, and the adhesion width of the liquid L on the material A is W2 in the figure. In FIG. 3, the dotted line ellipse indicates the spray range of the liquid L when the liquid diffusion direction by the nozzle N is set to the width direction of the material A. The major axis W1' of this dotted line ellipse is the spray width of the liquid L to the material A, and the adhesion width of the liquid L on the material A is W3 in the figure. W2 is shorter than W3, and W1 is the same length as W1'. In this way, in the liquid application method according to the present embodiment, the liquid spreading direction from the nozzle N is set to a diagonal direction with respect to the width direction (CD direction) of the material A. By setting the angle so as to be equal to W1, it is possible to adjust the deposition width of the liquid L on the material A while keeping the spray width of the liquid L constant at W1. The larger the angle at which the liquid diffusion direction by the nozzle N is oblique to the width direction (CD direction) of the material A, the narrower the deposition width of the liquid L on the material A, and the smaller the angle, the wider the deposition width of the liquid L on the material A. Thus, the liquid deposition method according to this embodiment is capable of adjusting the deposition width of the liquid L, and therefore it is possible to deposit the liquid L on the material A at a predetermined deposition width.

[0024] Furthermore, if the liquid L is sprayed beyond the material A, the liquid L may adhere to the conveying line M1 of the manufacturing equipment M, etc., and may contaminate the manufacturing equipment M. Furthermore, if the liquid L is sprayed beyond the specified application width of the material A, or if the liquid L is sprayed in a width narrower than the specified application width, the completed absorbent article may not be able to function as designed. However, according to the liquid application method of this embodiment, the liquid application width can be adjusted, so that the liquid L can be applied to the material A in the specified application width.

[0025] Furthermore, according to the liquid adhering method of this embodiment, the adhering width of the liquid L can be adjusted by setting the diffusion direction of the liquid L by the nozzle N, and therefore it is not necessary to replace the nozzle N in order to adjust the adhering width of the liquid L, and it is possible to improve the work efficiency of the liquid adhering process. Furthermore, according to the liquid adhering method of this embodiment, it is not necessary to prepare or purchase a new nozzle in order to adjust the adhering width of the liquid L, and it is possible to reduce costs.

[0026] Moreover, if too much liquid is applied to the material, problems such as mold growth on the material occur, and if too little liquid is applied, the effect of liquid application cannot be achieved, so it is necessary to apply an appropriate amount of liquid to the material. On the other hand, if the conveying speed (production speed) of the conveying line is increased, the spray pressure of the liquid needs to be increased in order to apply the same amount of liquid as when the conveying speed of the conveying line is slow, and in this case, the liquid spray width increases. In contrast, according to the liquid application method of this embodiment, even if the conveying speed of the conveying line is increased, the liquid application width can be adjusted without adjusting the liquid spray pressure by setting the angle of the liquid diffusion direction by the nozzle. As a result, according to the liquid application method of this embodiment, it is possible to prevent the liquid spray width from going beyond the material.

[0027] <Variation 1> Next, a liquid adhering method according to the first modified example of this embodiment will be described. The amount of the liquid L adhering to the material A can be adjusted by the spray pressure of the liquid L from the nozzle N. Specifically, the amount of spray can be increased by increasing the spray pressure, and the amount of the liquid L adhering can be increased by decreasing the spray pressure. However, the amount of the liquid L adhering also changes depending on the conveying speed of the conveying device that conveys the material. For example, when the spray pressure is constant, the amount of the liquid L adhering per unit area decreases as the conveying speed increases, and the amount of the liquid L adhering per unit area increases as the conveying speed decreases. For this reason, in order to keep the amount of the liquid L adhering per unit area constant, it is necessary to adjust the spray pressure according to the conveying speed. In general, the larger the spray pressure of the nozzle, the wider the spray width of the liquid L, and the smaller the spray pressure, the narrower the spray width of the liquid L. Therefore, adjusting the spray pressure will change the width of the liquid L adhering to the material.

[0028] Furthermore, when the conveying speed is increased in order to increase the production speed of absorbent articles, the amount of liquid L adhered per unit area decreases, so it is possible to increase the spray pressure in order to keep the amount of liquid L adhered constant, but increasing the spray pressure increases the spray width of the liquid L, which increases the width of the liquid L adhered to the material. Also, if the spray width of the liquid L becomes too wide, there is a risk that the liquid L will be sprayed outside the ends of the material in the width direction.

[0029] In addition, when the conveying speed is reduced to reduce the production speed of absorbent articles, As the amount of Liquid L attached to the material decreases, it is possible to increase the spray pressure in order to keep the amount of Liquid L attached constant, but lowering the spray pressure narrows the spray width of Liquid L, which results in a narrower width of attachment of Liquid L to the material. It is also possible to replace the nozzle with one that can spray Liquid L at an appropriate attachment width according to the conveying speed, but because it is necessary to temporarily stop the manufacturing equipment when replacing the nozzle, replacing the nozzle according to the conveying speed reduces the productivity of absorbent articles.

[0030] Therefore, in the liquid application method according to this modification, a process is provided in which the spray pressure of the nozzle is adjusted according to the conveying speed of the conveying device, and the spray width of the liquid is adjusted according to this spray pressure. With the liquid application method according to this modification, it is possible to apply liquid to the material at a predetermined application width without the need to replace the nozzle.

[0031] FIG. 4 is a flow chart showing an outline of the liquid adhering method according to this modified example. In the liquid adhering step according to this modified example, first, the spray pressure of the nozzle N is set according to the conveying speed of the conveying line (conveying device) to adjust the spray width of the liquid L (step S201). Next, the spray pressure of the nozzle N, that is, the angle of the diffusion direction of the liquid L is set according to the spray width of the liquid L to adjust the adhering width (step S202). The amount of liquid sprayed from the nozzle per unit time is increased by increasing the spray pressure of the nozzle as the conveying speed increases, and the amount of liquid sprayed from the nozzle per unit time is decreased by decreasing the spray pressure of the nozzle as the conveying speed decreases, thereby keeping the amount of liquid sprayed per unit area of ​​the material constant. In addition, increasing the spray pressure of the nozzle widens the spray width of the liquid, and decreasing the spray pressure of the nozzle narrows the spray width of the liquid. In the liquid adhering method according to this embodiment, even if the spray width of the liquid changes due to the spray pressure of the nozzle, the angle of the diffusion direction of the liquid L by the nozzle can be set to adjust the adhering width of the liquid on the material.

[0032] In addition, in this modified example, the spray pressure may be set based on the transport speed of the transport line and the amount of liquid sprayed onto the material (total amount sprayed) (step S201), and the direction in which the liquid L is spread by the nozzle may be adjusted according to the spray pressure (step S202).

[0033] <Variation 2> Next, a liquid adhering method according to Modification 2 of this embodiment will be described. In this modification, a liquid adhering method will be described for a case where a groove extending along the conveying direction is formed in the center of the width direction of material A. Fig. 5 is a diagram showing an example of an absorbent article manufacturing device used in a manufacturing method of absorbent articles using the liquid adhering method according to this modification, as viewed from above vertically to the conveying direction.

[0034] As shown in FIG. 5, a groove S extending along the conveying direction of the material A is formed in the center of the width of the material A. The liquid spraying device M2 has a plurality of nozzles for spraying the liquid L. The plurality of nozzles are composed of a nozzle NL (corresponding to the "first nozzle" in this application) for spraying the liquid L on one end side (left side in the conveying direction) of the groove S in the width direction, and a nozzle NR (corresponding to the "second nozzle" in this application) for spraying the liquid L on the other end side (right side in the conveying direction) of the groove S in the width direction. In FIG. 5, the liquid spraying device M2 and the nozzles NL and NR are illustrated with dotted lines in order to illustrate and explain the bottom surface of the elliptical cone of the liquid L sprayed from the nozzles NL and NR in an elliptical cone shape. The liquid application method of this modified example makes it possible to adjust the application width W12 of the liquid L on the material A while keeping the spray width W11 constant by setting the direction of liquid diffusion by the nozzles NL, NR at an angle that is oblique to the width direction (CD direction) of the material A.

[0035] In addition, since the inside of the trench S is outside the design liquid spray range of the material A, spraying the liquid L therein is undesirable because the transfer line M1 of the manufacturing equipment M would be contaminated by the liquid L. Furthermore, when the material A is covered with a sheet material such as tissue paper (for example, a core wrap sheet), the liquid L may be scattered on the sheet material at the portion overlapping the groove S, which is undesirable. In this case, the sheet material is subjected to the weight of the material A at the lower side in the groove S, and the sheet material is likely to tear if this portion becomes wet with the liquid L. Therefore, in this modified example, the liquid scattering device M2 has a nozzle NL that sprays the liquid L on one end side of the groove S in the width direction, and a nozzle NR that sprays the liquid L on the other end side of the groove S in the width direction. The liquid attachment method according to this modified example can adjust the attachment width of the liquid L by setting the diffusion direction of the liquid L by the nozzles NL and NR at an angle that is oblique to the width direction of the material A. This makes it possible to prevent the liquid L from being scattered in the groove S of the material A.

[0036] <Variation 3> Next, a liquid adhering method according to Modification 3 of this embodiment will be described. In this modification, a liquid adhering method will be described in the case where a groove S extending along the conveying direction is formed in the center of the width direction of the material A. Fig. 6 is a diagram showing an example of an absorbent article manufacturing apparatus used in a manufacturing method of absorbent articles using the liquid adhering method according to this modification, when the manufacturing apparatus M is viewed from the downstream side to the upstream side.

[0037] In this modified example, similar to modified example 2, the liquid spraying device M2 has nozzles NL, NR. In the liquid adhering method according to this modified example, the nozzles NL, NR are tilted outward in the width direction of the material A (outward in the CD direction) with respect to the vertical direction to adjust the adhering width of the liquid L. By tilting the nozzles NL, NR outward in the width direction as in this modified example, the spraying width of the liquid L can be made wider on the outside in the width direction than on the inside in the width direction, thereby making it possible to prevent the liquid L from being sprayed into the grooves S of the material A.

[0038] <Modification 4> Next, a liquid adhering method according to a fourth modified example of this embodiment will be described. In this modified example, a liquid adhering method will be described for a case in which a groove extending along the conveying direction is formed in the center of the width direction of the material A. Fig. 7 is a diagram showing an example of an absorbent article manufacturing apparatus used in a manufacturing method for absorbent articles in which the liquid adhering method according to this modified example is used, when the manufacturing apparatus M is viewed from the downstream side to the upstream side.

[0039] In this modification, the liquid spraying device M2 has nozzles NL and NR, as in the above modification 2. The manufacturing device M according to this modification also includes a guide G that tilts the material A outward in the width direction with respect to the vertical direction. The guide G is installed on the conveying line M1, and has a flat portion G1 on which the center portion in the width direction, which is the formation area of ​​the groove S of the material A, is placed, and an inclined portion G2 on which the outer side of the material A in the width direction from the groove S is placed and which inclines the outer side of the material A in the width direction from the groove S outward in the width direction with respect to the vertical direction. In the liquid adhering method according to this modification, the material A is tilted outward in the width direction (outward in the CD direction) with respect to the vertical direction to adjust the adhering width of the liquid L. By tilting the nozzle A outward in the width direction as in this modification, the spraying width of the liquid L can be made wider on the outer side in the width direction than on the inner side in the width direction, and this makes it possible to suppress the liquid L from being sprayed in the groove S of the material A.

[0040] As described above, according to the liquid adhering method of this embodiment, the adhering width of the liquid L can be adjusted, so that the liquid can be adhered to the material at a predetermined adhering width. Furthermore, the liquid adhering method of this embodiment can be used in a liquid adhering step in which the liquid is adhered to the material used in the absorbent article. Therefore, the liquid adhering method of this embodiment can be used in a manufacturing method of the absorbent article.

[0041] As an example of an absorbent article using the above manufacturing method, an absorbent pad will be described. In this embodiment, the absorbent pad is made up of a front body and a back body that are disposed opposite the abdomen of a wearer. The direction connecting the front body and the back body, which are arranged opposite to the front body, is defined as the longitudinal direction. Between the front body (one side in the longitudinal direction) and the back body (the other side in the longitudinal direction) (the center in the longitudinal direction), the crotch part is located under the crotch of the wearer (opposed to the crotch). Furthermore, when the absorbent pad is worn by the wearer (hereinafter abbreviated as "worn state"), the side facing the wearer's skin (the inner side when worn) is defined as the skin-facing side, and the opposite side to the skin-facing side (the outer side when worn) is defined as the non-skin-facing side. Furthermore, the direction connecting the skin-facing side and the non-skin-facing side is defined as the thickness direction, and the direction perpendicular to both the longitudinal direction and the thickness direction is defined as the width direction. In addition, the view from the thickness direction is defined as a planar view.

[0042] FIG. 8 is a plan view of the absorbent pad 1 as viewed from the skin side. The absorbent pad 1 is used to absorb and retain liquids such as urine, and can be used alone or layered on the inside of a disposable diaper. The absorbent pad 1 has a front body region 3 located on the wearer's abdomen side when worn, a crotch region 5 located between the legs, and a back body region 7 located on the back side. The absorbent pad 1 is divided into the front body region 3, the crotch region 5, and the back body region 7 when viewed in the longitudinal direction. The direction perpendicular to the longitudinal direction is the width direction (short direction) of the absorbent pad 1. When viewed in plan, the absorbent pad 1 has the narrowest width in the crotch region 5, and the crotch region 5 has a narrow gourd shape.

[0043] In the following, when the absorbent pad 1 is viewed in the longitudinal direction, the front body region 3 side is relatively referred to as the "front", "front side", "forward" or "abdominal side", the rear body region 7 side is relatively referred to as the "rear", "rear side", "rear" or "back side", the left side relatively from the rear side to the front side is relatively referred to as the "left", "left side" or "left side", and the right side relatively from the rear side to the front side is relatively referred to as the "right", "right side" or "right side". The front-to-rear direction of the absorbent pad 1 is the longitudinal direction, and the left-to-right direction of the absorbent pad 1 is the width direction. The direction perpendicular to the front-to-rear and left-to-right directions is the thickness direction of the absorbent pad 1.

[0044] As shown in Fig. 8, the absorbent pad 1 includes a top sheet 11 arranged on the skin-facing side when worn. The top sheet 11 is the portion (skin-facing side) that contacts the wearer's skin when the absorbent pad 1 is worn, and is made of a liquid-permeable material that allows liquids such as urine to pass through. Specifically, the top sheet 11 is made of woven fabric, nonwoven fabric, porous film, etc. Note that the nonwoven fabric may be made of thermoplastic resin fibers such as polypropylene, polyethylene, polyester, nylon, etc. that have been hydrophilized, or may be an air-through nonwoven fabric, point-bonded nonwoven fabric, spun-bonded nonwoven fabric, melt-blown nonwoven fabric, etc.

[0045] The absorbent pad 1 also includes a back sheet 13 disposed on the side opposite to the skin surface when worn. The back sheet 13 is the non-skin surface (outer surface) opposite to the skin surface, and is made of a liquid-impermeable material that does not allow liquids such as urine to pass through. Specifically, a liquid-impermeable film made of polyethylene resin is used for the back sheet 13. Note that, in order to obtain breathability to prevent stuffiness when worn while maintaining liquid impermeability, it is preferable to use a microporous polyethylene film in which a plurality of fine pores of 0.1 to 4 μm are formed for the back sheet 13.

[0046] The top sheet 11 and the back sheet 13 are joined to each other at their respective peripheral edges. The absorbent pad 1 is provided with an absorbent body 14 disposed between the top sheet 11 and the back sheet 13, and absorbs liquids such as urine. The absorbent body 14 has an upper absorbent body 15 disposed on the top sheet 11 side, and a lower absorbent body 17 disposed on the back sheet 13 side. The upper absorbent body 15 has a gourd shape similar to that of the absorbent pad 1 in plan view. The lower absorbent body 17 is disposed below the upper absorbent body 15 when viewed from the top sheet 11 side, and has a rectangular shape with the long side extending in the longitudinal direction of the absorbent pad 1 in plan view. The upper absorbent body 15 is formed larger than the lower absorbent body 17 in plan view. The absorbent pad 1 is relatively large when liquids such as urine are excreted, and the upper absorbent body 15 is formed on the top sheet 11 side. The urine can be quickly absorbed by the upper absorbent body 15 arranged in the absorbent pad 1. The longitudinal direction of the absorbent body 14 is the longitudinal direction of the upper absorbent body 15 and the lower absorbent body 17, and coincides with the longitudinal direction of the absorbent pad 1. The width direction of the absorbent body 14 is the width direction of the upper absorbent body 15 and the lower absorbent body 17, and coincides with the width direction of the absorbent pad 1.

[0047] The upper absorbent body 15 and the lower absorbent body 17 are made of fluff pulp obtained by crushing fibrous materials such as coniferous trees, super absorbent polymer (SAP), hydrophilic sheets, or combinations of these. SAP absorbs about 10 to 100 times its own weight in liquid. For example, granular SAP having a diameter of about 0.1 to 0.5 mm before absorbing liquid is used.

[0048] The absorbent pad 1 also has a groove 21 formed penetrating the upper absorbent body 15 in the thickness direction. The groove 21 extends in the longitudinal direction of the absorbent body 14 including an area corresponding to the urethral opening, which is the position where the wearer urinates, on the top sheet side (upper absorbent body 15) of the absorbent body 14, and is formed in the center of the absorbent body 14 in the width direction.

[0049] The absorbent pad 1 also has SAP layers 23L, 23R disposed between the upper absorbent body 15 and the lower absorbent body 17. The SAP layers 23L, 23R are formed by gathering together a plurality of particles of superabsorbent polymer (SAP). The SAP layers 23L, 23R contain a plurality of SAP particles and can absorb and retain liquid introduced between the upper absorbent body 15 and the lower absorbent body 17. As shown in FIG. 8, the SAP layer 23L is disposed on the left side of the groove 21, and the SAP layer 23R is disposed on the right side of the groove 21. In this manner, the SAP layers 23L, 23R are disposed on both sides of the groove 21 along the longitudinal direction of the groove 21. In addition, the SAP layers 23L, 23R are formed in a rectangular shape in plan view. The SAP layers 23L, 23R may be formed in a polygonal shape or an elliptical shape other than a rectangular shape in plan view.

[0050] As described above, the absorbent pad 1 according to this embodiment includes the upper absorbent body 15, the lower absorbent body 17, the grooves 21, and the SAP layers 23L and 23R. The longitudinal directions of the upper absorbent body 15, the lower absorbent body 17, the grooves 21, and the SAP layers 23L and 23R are aligned. The grooves 21 and the SAP layers 23L and 23R are arranged approximately parallel to each other.

[0051] Furthermore, the absorbent pad 1 has three-dimensional gathers (not shown) arranged along the left and right edges of the lower absorbent body 17 when viewed from the skin-facing side. The three-dimensional gathers are joined to the top sheet 11 and suppress side leakage of liquid.

[0052] Fig. 9 is a cross-sectional view of the absorbent pad 1 shown in Fig. 8 cut along line AA. In Fig. 9, in order to make each component of the absorbent pad 1 easier to understand, gaps are provided between each component, but in reality, there are almost no gaps between each component.

[0053] As shown in FIG. 9, the absorbent pad 1 according to this embodiment includes a core wrap sheet 30 (not shown in FIG. 8) that wraps the entire absorbent body 14. The core wrap sheet 30 has an upper layer sheet 31 arranged on the upper absorbent body 15 side and a lower layer sheet 33 arranged on the lower absorbent body 17 side. The upper layer sheet 31 is arranged between the top sheet 11 and the upper absorbent body 15, and the lower layer sheet 33 is arranged between the back sheet 13 and the lower absorbent body 17. The lower layer sheet 33 has a portion that covers the side portions of the upper absorbent body 15 and the lower absorbent body 17, is routed between the top sheet 11 and the upper absorbent body 15, and is joined to the upper layer sheet 31 between the top sheet 11 and the upper absorbent body 15. In this way, the upper layer sheet 31 and the lower layer sheet 33 are joined to each other and integrated, and wrap the entire upper absorbent body 15 and the lower absorbent body 17. The upper layer sheet 31 and the lower layer sheet 33 have For example, thin paper such as tissue paper or nonwoven fabric is used. The upper layer sheet 31 and the lower layer sheet 33 may be integrally formed, or may be joined to the side of the upper layer absorbent body 15 or the lower layer absorbent body 17, or between the back sheet 13 and the lower layer absorbent body 17. In the absorbent pad 1 according to this embodiment, the entire absorbent body 14 is wrapped with the core wrap sheet 30, so that liquid such as urine can be diffused over the entire surface of the absorbent body 14 and absorbed by the entire absorbent body 14.

[0054] The SAP layers 23L, 23R are formed by scattering SAP particles on the lower absorbent body 17. In addition, the SAP layers 23L, 23R are sandwiched between the upper absorbent body 15 and the lower absorbent body 17. Therefore, even if the absorbent pad 1 moves due to the wearer's movements, the SAP particles contained in the SAP layers 23L, 23R can be prevented from moving below the grooves 21 or falling out of the lower absorbent body 17.

[0055] Furthermore, by disposing the SAP layers 23L, 23R between the upper absorbent body 15 and the lower absorbent body 17, urine once absorbed by the pulp of the lower absorbent body 17 can be moved to the SAP layers 23L, 23R by capillary action. This allows the absorbent pad 1 to hold urine in the SAP layers 23L, 23R, which have a higher urine retention capacity, thereby preventing urine leakage.

[0056] As described above, the absorbent pad 1 according to this embodiment has a structure in which, viewed in the thickness direction from the skin side, the top sheet 11, the upper sheet 31, part of the lower sheet 33, the upper absorbent body 15, the SAP layers 23L and 23R, the lower absorbent body 17, part of the lower sheet 33, and the back sheet 13 are laminated in this order. In addition, the peripheral edges of the top sheet 11 and the back sheet 13 are joined to each other, so that the upper sheet 31, the lower sheet 33, the upper absorbent body 15, the SAP layers 23L and 23R, and the lower absorbent body 17 are surrounded and sealed by the top sheet 11 and the back sheet 13.

[0057] For example, the above-mentioned liquid adhering method can be used in the manufacturing process of such an absorbent pad 1. For example, in the process of producing the upper-layer absorbent body 15 and the lower-layer absorbent body 17, the above-mentioned liquid adhering method may be used for the materials for the upper-layer absorbent body 15 and the lower-layer absorbent body 17. According to the manufacturing method of the absorbent pad 1 using the above-mentioned liquid adhering method, liquid can be adhered to the materials for the upper-layer absorbent body 15 and the lower-layer absorbent body 17 in a predetermined adhering width.

[0058] <Other embodiments> Although the embodiments of the present invention have been described above, the above-mentioned various embodiments can be combined as much as possible. In addition, the liquid spraying device M2 may have three or more nozzles for spraying the liquid L. [Explanation of symbols]

[0059] 1. Absorbent pad 3. Front body area 5...Inseam area 7. Back body area 11. Top sheet 13. Back seat 14. Absorber 15. Upper absorber 17. Lower absorber 21·Groove 23L··SAP layer 23R··SAP layer 30··Core wrap sheet 31. Upper sheet 33 Lower sheet M··Manufacturing equipment M1··Conveyor line M2·Liquid spraying device N,NL,NR Nozzle A. Materials L··Liquid

Claims

1. 1. A liquid application method for applying liquid to a material made of a fibrous material conveyed in a fixed direction by a conveying device by spraying the liquid from a liquid spraying device, the method comprising: The liquid spraying device has a nozzle for spraying the liquid, and sprays the liquid in an elliptical cone shape with the nozzle outlet as an apex; the direction of diffusion of the liquid by the nozzle is the major axis direction of the bottom surface of the elliptical cone; The width of the liquid applied is adjusted by setting the direction of the liquid spread by the nozzle at an angle oblique to the width direction of the material. Including, A groove is formed in a central portion of the material in the width direction, the groove extending along a conveying direction of the material, The liquid spraying device has a plurality of the nozzles, the plurality of nozzles include a first nozzle that sprays the liquid toward one end side of the groove in the width direction, and a second nozzle that sprays the liquid toward the other end side of the groove in the width direction, adjusting the deposition width by setting the angles of the first nozzle and the second nozzle; Liquid application method.

2. adjusting a spray width of the liquid by setting a spray pressure of the nozzle in accordance with a conveying speed of the conveying device; The adhesion width is adjusted by setting the angle of the diffusion direction according to the spray width. The liquid deposition method according to claim 1 .

3. The deposition width is adjusted by tilting the first nozzle and the second nozzle outward in the width direction with respect to a vertical direction. The liquid depositing method according to claim 1 or 2.

4. The deposition width is adjusted by tilting the material outward in the width direction relative to the vertical direction. The liquid deposition method according to any one of claims 1 to 3. The liquid application method according to claim 1 .

5. The method includes a liquid applying step of applying a liquid to the material to be used in the absorbent article by using the liquid applying method according to any one of claims 1 to 4. A method for manufacturing an absorbent article.

6. A conveying device that conveys a material made of a fibrous material in a fixed direction; a liquid spraying device having a nozzle for spraying a liquid and spraying the liquid toward the material on the conveying device; The liquid spraying device sprays the liquid in an elliptical cone shape with the nozzle outlet as an apex, the direction of diffusion of the liquid by the nozzle is the major axis direction of the bottom surface of the elliptical cone; the nozzle is set at an angle such that the liquid diffusion direction is oblique to the width direction of the material, thereby adjusting the liquid deposition width; A groove is formed in a central portion of the material in the width direction, the groove extending along a conveying direction of the material, The liquid spraying device has a plurality of the nozzles, the plurality of nozzles include a first nozzle that sprays the liquid toward one end side of the groove in the width direction, and a second nozzle that sprays the liquid toward the other end side of the groove in the width direction, The liquid spraying device adjusts the deposition width by setting the angles of the first nozzle and the second nozzle. An apparatus for manufacturing absorbent articles.

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