JP7651871B2 - Liquid application method, absorbent article manufacturing method using the same, and absorbent article manufacturing device - Google Patents

Description

The present invention relates to a liquid application method, a method for manufacturing absorbent articles using the same, and an apparatus for manufacturing absorbent articles.

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

JP 2019-213855 A

In the manufacturing process of absorbent articles, materials used in the absorbent articles are transported by a transport device. The manufacturing process of absorbent articles may include a step of applying liquid to the materials while they are being transported by the transport device. In order to achieve the functions required for the absorbent article, it is necessary to apply liquid to the materials at a specified application width. However, no specific proposal has been made regarding the method of applying liquid.

The present invention aims to provide a technology that can apply liquid to materials at a specified application width.

To solve the above problem, in this invention, the direction in which the liquid is spread from the nozzle is diagonal to the width direction of the material.

In detail, the present invention is a liquid application method for applying liquid to a material made of a fibrous material that is 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.

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 conveying speed of the conveying device, and the deposition width may be adjusted by setting the angle of the diffusion direction according to the spray width.

In the above liquid application method, a groove is formed in the center of the width direction of the material, extending along the transport 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 from the groove to one end side in the width direction, and a second nozzle that sprays the liquid from the groove to the other end side in the width direction, and the application width may be adjusted by setting the angle of the first nozzle and the second nozzle.

In the above liquid deposition method, the deposition width may be adjusted by tilting the first nozzle and the second nozzle outward in the width direction relative to the vertical direction.

In the above liquid application method, the application width may be adjusted by tilting the material outward in the width direction relative to the vertical direction.

The present invention can also be seen as 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 application step in which liquid is applied to the material used in the absorbent article using the liquid application method.

The present invention can also be seen from the perspective of an absorbent article manufacturing apparatus. For example, the present invention is an absorbent article manufacturing apparatus that includes a conveying device that conveys a material made of a fibrous material in a fixed direction, and a liquid spraying device that has 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.

According to the present invention, liquid can be applied to materials at a predetermined application width.

FIG. 1 is a flow chart outlining a liquid deposition method. FIG. 2 is a diagram (part 1) showing an example of an apparatus for manufacturing absorbent articles. FIG. 3 is a diagram (part 2) showing an example of an apparatus for manufacturing absorbent articles. FIG. 4 is a flow chart outlining the liquid deposition method. FIG. 5 is a diagram showing an example of an absorbent article manufacturing apparatus. FIG. 6 is a diagram showing an example of an apparatus for manufacturing absorbent articles. FIG. 7 is a diagram showing an example of an apparatus for manufacturing absorbent articles. FIG. 8 is a plan view of the absorbent pad. FIG. 9 is a cross-sectional view of the absorbent pad when cut in the width direction.

Below, an embodiment of the present invention will be described 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>
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 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. A liquid is attached to the material during transportation 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 spread on the material, a liquid such as water or a chemical solution is attached to the material in a step before the process 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, in order to improve the comfort of wearing the absorbent article, medicinal liquids such as skin care agents and antibacterial agents may be attached to the material.

In order to realize the necessary functions of an absorbent article, it is necessary to apply liquid to the material in a predetermined application width. Note that the application width is the width direction (CD) of the material perpendicular to the longitudinal direction (MD).
is the width of the liquid deposit in the direction

The liquid application method according to this embodiment is a method of applying liquid to materials conveyed in a fixed direction by a conveying device by spraying the liquid from a liquid spraying device onto the materials. The liquid spraying device has a nozzle that sprays liquid toward the materials being conveyed. It is desirable that the liquid be applied to a predetermined application width in the design of the materials. For example, when applying liquid to a material to retain SAP particles on the material, if the application width of the liquid is narrower than the arrangement width of the SAP particles, it will not be possible to retain all of the SAP particles on the material. Also, when applying a medicinal liquid such as a skin care agent or antibacterial agent to the material, it will not be possible to apply the medicinal liquid to the required area, and the full effect of the medicinal liquid will not be obtained.

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, there is no need to replace the nozzle, and liquid can be applied to the material at a predetermined application width.

Figure 1 is a flow chart showing an overview of the liquid application method according to this embodiment. In the liquid application process according to this embodiment, the liquid application width is adjusted by setting the direction of liquid spread by the nozzle at an angle diagonal to the width direction of the material (step S101). The liquid spraying device sprays liquid in an elliptical cone shape with the nozzle outlet as the apex. The bottom of this elliptical cone is the liquid application range on the material, and the long axis direction of the ellipse that is the bottom is the direction of liquid spread by the nozzle. In the liquid application method according to this embodiment, the nozzle is rotated to set the direction of liquid spread by the nozzle at an angle diagonal to the width direction of the material. This makes it possible to adjust the liquid application width by setting the direction of liquid spread by the nozzle at an angle diagonal to the width direction of the material.

Next, the liquid attachment 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 attachment method according to the present embodiment. Fig. 2 shows a state seen from the side relative to the conveying direction, and Fig. 3 shows a state seen from above vertically relative to the conveying direction. The present manufacturing apparatus M used in the manufacture of absorbent articles includes a conveying line M1 (an example of the "conveying apparatus" in the present application) and a liquid spraying device M2. The conveying line M1 is a conveyor that conveys material A, which is a so-called continuous sheet, in a certain direction (the right-facing arrow direction, which is the "conveying direction (MD direction)" 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 liquid L toward the material A, and sprays liquid L on the material A on the conveying line M1. The liquid L is sprayed toward the material A, so that the liquid L is attached to the material A. The spray pressure of nozzle N is adjusted to 0.01 MPa to 0.5 MPa so that a predetermined amount of liquid is applied depending on the conveying speed of material A.

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. W1, which is the major axis of this solid line ellipse, is the spray width of the liquid L on the material A, and the adhesion width of the liquid L on the material A is W2 in the figure. In FIG. 3, the ellipse shown by the dotted line 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. W1', which is the major axis of this dotted line ellipse, is the spray width of the liquid L on 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, the liquid adhering method according to this embodiment can adjust the adhering width of the liquid L on the material A while keeping the spray width of the liquid L constant W1 by setting the spreading direction of the liquid by the nozzle N at an angle oblique to the width direction (CD direction) of the material A. The larger the angle at which the spreading direction of the liquid by the nozzle N is oblique to the width direction (CD direction) of the material A, the narrower the adhering width of the liquid L on the material A, and the smaller the angle, the wider the adhering width of the liquid L on the material A. Thus, the liquid adhering method according to this embodiment can adjust the adhering width of the liquid L, so that the liquid L can be adhered to the material A at a predetermined adhering width.

Furthermore, if liquid L is sprayed beyond the material A, it may adhere to the conveying line M1 of the manufacturing equipment M, and may contaminate the manufacturing equipment M. Furthermore, if liquid L is sprayed beyond the specified adhesion width of material A, or if liquid L is sprayed at a width narrower than the specified adhesion width, there is a risk that the completed absorbent article will not be able to function as designed. However, according to the liquid adhesion method of this embodiment, the liquid adhesion width can be adjusted, so that liquid L can be adhered to material A at the specified adhesion width.

In addition, according to the liquid application method of this embodiment, the application width of liquid L can be adjusted by setting the diffusion direction of liquid L by nozzle N, so there is no need to replace nozzle N to adjust the application width of liquid L, and the work efficiency of the liquid application process can be improved. In addition, according to the liquid application method of this embodiment, there is no need to prepare or purchase a new nozzle to adjust the application width of liquid L, and costs can be reduced.

In addition, if too much liquid is applied to the material, problems such as mold growth on the material may 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 liquid spray pressure must be increased 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 will be wider. 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, the liquid application method of this embodiment can prevent the liquid spray width from extending beyond the material.

<Modification 1>
Next, a liquid adhering method according to a 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 a 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.

In addition, when the conveying speed is increased 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. However, when the spray pressure is increased, the spray width of liquid L increases, and the width of liquid L adhered to the material increases. Furthermore, if the spray width of liquid L becomes too wide, there is a risk that liquid L will be sprayed outside the widthwise ends of the material.

Furthermore, when the conveying speed is reduced to slow the production speed of absorbent articles, the amount of liquid L attached per unit area decreases, so it is possible to increase the spray pressure to keep the amount of liquid L attached constant, but lowering the spray pressure narrows the spray width of liquid L, which narrows the width of attachment of liquid L on the material. It is also possible to replace the nozzle with one that can spray liquid L with an appropriate attachment width depending on the conveying speed, but since it is necessary to temporarily stop the manufacturing equipment when replacing the nozzle, replacing the nozzle depending on the conveying speed reduces the productivity of absorbent articles.

Therefore, in the liquid application method according to this modified example, 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 liquid spray width is adjusted according to this spray pressure. With the liquid application method according to this modified example, there is no need to replace the nozzle, and liquid can be applied to the material at a predetermined application width.

Figure 4 is a flow chart showing an outline of the liquid attachment method according to this modified example. In the liquid attachment process 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, i.e., the angle of the diffusion direction of the liquid L is set according to the spray width of the liquid L, to adjust the attachment 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 reduced 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. The liquid attachment method according to this embodiment can adjust the spray width of the liquid on the material by setting the angle of the diffusion direction of the liquid L by the nozzle, even if the spray width of the liquid changes depending on the spray pressure of the nozzle.

In addition, in this modified example, the spray pressure may be set based on the conveying speed of the conveying line and the amount 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).

<Modification 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 the 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.

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 also 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 of the groove S in the width direction (left side in the conveying direction), and a nozzle NR (corresponding to the "second nozzle" in this application) for spraying the liquid L on the other end side of the groove S in the width direction (right side in the conveying 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. In the liquid deposition method of this modified example, the liquid spreading direction by the nozzles NL and NR is set at an angle that is oblique to the width direction (CD direction) of the material A, so that the deposition width W12 of the liquid L on the material A can be adjusted while keeping the spray width of the liquid L constant W11.

In addition, since the groove S is outside the designed liquid spray range for the material A, spraying the liquid L therein is undesirable because the conveying line M1 of the manufacturing equipment M would be contaminated by the liquid L.
In addition, 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 because it may cause the sheet material to tear. In addition, in this case, the sheet material is subjected to the load of the material A on the lower side in the groove S, and if this portion of the sheet material becomes wet with the liquid L, it is likely to tear. 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. In the liquid attachment method according to this modified example, the spreading direction of the liquid L by the nozzles NL and NR can be adjusted at an angle that is oblique to the width direction of the material A, thereby making it possible to prevent the liquid L from being scattered in the groove S of the material A.

<Modification 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.

In this modified example, as in modified example 2 above, the liquid spraying device M2 has nozzles NL and NR. In the liquid application method of this modified example, the nozzles NL and NR are tilted outward in the width direction of the material A (outward in the CD direction) relative to the vertical direction to adjust the application width of the liquid L. By tilting the nozzles NL and NR outward in the width direction as in this modified example, the spray 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 preventing the liquid L from being sprayed into the grooves S of the material A.

<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 using the liquid adhering method according to this modified example, when the manufacturing apparatus M is viewed from the downstream side to the upstream side.

In this modification, the liquid spraying device M2 has nozzles NL and NR, as in the modification 2. The manufacturing device M according to this modification also has 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 tilts 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 attachment method according to this modification, the attachment width of the liquid L is adjusted by tilting the material A outward in the width direction (outward in the CD direction) with respect to the vertical direction. As in this modification, by tilting the nozzle A outward in the width direction, the spray 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 into the groove S of the material A.

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 process in which liquid is adhered to materials used in absorbent articles. Therefore, the liquid adhering method of this embodiment can be used in a manufacturing method for absorbent articles.

As an example of an absorbent article using the above manufacturing method, an absorbent pad will be described. In this embodiment, the direction connecting the front body arranged opposite the wearer's abdomen and the back body arranged opposite the back of the absorbent pad is 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), a crotch part arranged under the wearer's crotch (opposed to the crotch) is located. In addition, 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 the skin side, and the opposite side of the skin side (the outer side when worn) is the non-skin side. Furthermore, the direction connecting the skin side and the non-skin side is the thickness direction, and the direction perpendicular to both the longitudinal direction and the thickness direction is the width direction. In addition, the view from the thickness direction is a plan view.

Figure 8 is a plan view of the absorbent pad 1 as seen 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. When worn, the absorbent pad 1 has a front body region 3 located on the wearer's abdomen side, a crotch region 5 located between the legs, and a rear body region 7 located on the back side. When viewed in the longitudinal direction, the absorbent pad 1 is divided into the front body region 3, the crotch region 5, and the rear body region 7. The direction perpendicular to the longitudinal direction is the width direction (short direction) of the absorbent pad 1. When viewed in a plan view, the absorbent pad 1 has the narrowest width in the crotch region 5, and the crotch region 5 has a narrow gourd shape.

In the following, when the absorbent pad 1 is viewed in the longitudinal direction, the front body region 3 side will be referred to relatively as the "front", "front side", "forward" or "abdominal side", the rear body region 7 side will be referred to relatively as the "rear", "rear side", "rear" or "back side", the left side relatively from the rear side to the front side will be referred to relatively as the "left", "left side" or "left side", and the right side relatively from the rear side to the front side will be referred to relatively 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.

As shown in FIG. 8, the absorbent pad 1 has a top sheet 11 arranged on the skin-facing side when worn. The top sheet 11 is the part (skin-facing side) that comes into contact with 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 may be made of woven fabric, nonwoven fabric, porous film, or the like. Note that the nonwoven fabric may be made of thermoplastic resin fibers such as polypropylene, polyethylene, polyester, or nylon that have been hydrophilized, or may be an air-through nonwoven fabric, point-bonded nonwoven fabric, spun-bonded nonwoven fabric, melt-blown nonwoven fabric, or the like.

The absorbent pad 1 also includes a back sheet 13 that is arranged on the side opposite the skin surface when worn. The back sheet 13 is the non-skin surface (outer surface) opposite 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 it is preferable to use a microporous polyethylene film with multiple fine holes of 0.1 to 4 μm formed therein for the back sheet 13 in order to obtain breathability to prevent stuffiness when worn while maintaining liquid impermeability.

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 being the longitudinal direction of the absorbent pad 1 in plan view. In plan view, the upper absorbent body 15 is formed larger than the lower absorbent body 17. The absorbent pad 1 is relatively large when liquids such as urine are excreted, and the upper absorbent body 15 disposed on the top sheet 11 side can quickly absorb urine. 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.

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

The absorbent pad 1 also has a groove 21 formed through the upper absorbent body 15 in the thickness direction. The groove 21 extends in the longitudinal direction of the absorbent body 14, including the area corresponding to the urethral opening, which is the wearer's urination position, 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.

The absorbent pad 1 also has SAP layers 23L and 23R arranged between the upper absorbent body 15 and the lower absorbent body 17. The SAP layers 23L and 23R are formed by gathering together a plurality of particles of superabsorbent polymer (SAP). The SAP layers 23L and 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 arranged on the left side of the groove 21, and the SAP layer 23R is arranged on the right side of the groove 21. In this way, the SAP layers 23L and 23R are arranged on both sides of the groove 21 so as to follow the longitudinal direction of the groove 21. In addition, the SAP layers 23L and 23R are formed in a rectangular shape in a plan view. Note that the SAP layers 23L and 23R may be formed in other polygonal or elliptical shapes instead of rectangular shapes in a plan view.

As described above, the absorbent pad 1 according to this embodiment includes an upper absorbent body 15, a lower absorbent body 17, grooves 21, and 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. Furthermore, the grooves 21 and the SAP layers 23L and 23R are arranged approximately parallel to each other.

In addition, 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 side. The three-dimensional gathers are joined to the top sheet 11 to prevent side leakage of liquid.

Figure 9 is a cross-sectional view of the absorbent pad 1 shown in Figure 8 taken along line A-A. Note that in Figure 9, in order to make each component of the absorbent pad 1 easier to understand, gaps are shown between each component, but in reality, there are almost no gaps between each component.

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 to be 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 are made of, for example, thin paper such as tissue paper or nonwoven fabric. The upper layer sheet 31 and the lower layer sheet 33 may be integrally formed, or may be joined to the sides 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 liquids such as urine can be diffused over the entire surface of the absorbent body 14 and absorbed by the entire absorbent body 14.

The SAP layers 23L, 23R are formed by scattering SAP particles on the lower absorbent body 17. The SAP layers 23L, 23R are also sandwiched between the upper absorbent body 15 and the lower absorbent body 17. This prevents the SAP particles contained in the SAP layers 23L, 23R from moving below the grooves 21 or falling out of the lower absorbent body 17, even if the absorbent pad 1 moves due to the wearer's movements.

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

As described above, the absorbent pad 1 according to this embodiment has a structure in which, viewed from the skin side in the thickness direction, 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 portions 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.

In the manufacturing process of such an absorbent pad 1, for example, the liquid attachment method described above can be used. For example, in the process of creating the upper absorbent body 15 and the lower absorbent body 17, the liquid attachment method described above may be used on the materials for the upper absorbent body 15 and the lower absorbent body 17. According to the manufacturing method of the absorbent pad 1 using the liquid attachment method described above, liquid can be attached to the materials for the upper absorbent body 15 and the lower absorbent body 17 with a predetermined attachment width.

<Other embodiments>
Although the embodiments of the present invention have been described above, the above-described 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.

1. Absorbent pad 3. Front body region 5. Crotch region 7. Rear body region 11. Top sheet 13. Back sheet 14. Absorbent body 15. Upper absorbent body 17. Lower absorbent body 21. Groove 23L. SAP layer 23R. SAP layer 30. Core wrap sheet 31. Upper sheet 33. Lower sheet M. Manufacturing device M1. Conveyor line M2. Liquid spraying device N, NL, NR. Nozzle A. Material L. Liquid

Claims (6)

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;
adjusting a width of the liquid applied by setting a direction of spreading the liquid from the nozzle at an angle oblique to a width direction of the material ;
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. 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 . 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. 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 . 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. 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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