Absorbent article and manufacturing method of the same

Abstract

To provide an absorbent article including an absorber comprising an absorbent core encapsulated in a core wrap sheet of crepe paper, and capable of achieving both improvement of rewet by increasing liquid diffusibility, and suppression of breakage of the core wrap sheet.SOLUTION: An absorbent article 1 includes an absorber 11. The absorber comprises an absorbent core 11a, a skin-side core wrap sheet 11b1 positioned on a skin side in a thickness direction of the absorbent core, and a non-skin-side core wrap sheet 11b2 positioned on a non-skin side in the thickness direction of the absorbent core. The skin-side core wrap sheet and the non-skin-side core wrap sheet are composed of crepe paper having unevenness. A degree of unevenness of the skin-side core wrap sheet is smaller than a degree of unevenness of the non-skin-side core wrap sheet.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] There is known an absorbent article having an absorbent body including an absorbent core wrapped with a core wrap sheet of crepe paper. For example, Patent Document 1 discloses an absorbent article having a longitudinally elongated absorbent body having an absorbent core containing a water-absorbent polymer, an inner sheet arranged on the skin-facing side of the absorbent core, and an outer sheet that wraps the entire absorbent core on which the inner sheet is arranged. The outer sheet and the inner sheet each carry the same type of functional particles. The outer sheet has a faster liquid permeation rate than the inner sheet. The outer sheet has a higher crepe rate than the inner sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-68680 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the absorbent core is entirely wrapped in the outer sheet, so that the outer sheet is a core wrap sheet. However, the outer sheet has a high crepe ratio, that is, the degree of unevenness (the number of wrinkles and / or the size of the wrinkles) is large. Therefore, the outer sheet is likely to have low diffusibility of body fluids in the planar direction (hereinafter, simply referred to as "liquid diffusibility"). In that case, body fluids that reach the outer sheet from the top sheet tend to transfer to the absorbent core as they are. In that case, the absorption of body fluids in the absorbent core tends to be concentrated in a relatively narrow area of ​​the absorbent body in a planar view. As a result, the absorbent article may be prone to rewetting after absorbing body fluids.

[0005] In order to improve the liquid dispersibility and suppress rewetting, it is possible to reduce the crepe ratio of the outer sheet, i.e., to reduce the degree of unevenness. However, if the degree of unevenness is reduced, the outer sheet becomes less likely to deform. Therefore, there is a risk that the outer sheet will break due to external forces applied to the absorbent article in response to the wearer's movements during use.

[0006] Therefore, the object of the present invention is to provide an absorbent article and a manufacturing method thereof, which has an absorbent body including an absorbent core wrapped in a core wrap sheet of crepe paper, and which is capable of achieving both improved rewetting by improving the liquid diffusion in the planar direction in the core wrap sheet and suppression of breakage of the core wrap sheet. [Means for solving the problem]

[0007] One aspect of the present invention is an absorbent article having a longitudinal direction, a width direction and a thickness direction that are perpendicular to each other, and comprising a top sheet, a back sheet and an absorbent body located between the top sheet and the back sheet, wherein the absorbent body includes an absorbent core containing pulp fibers, a skin-side core wrap sheet located on the skin side of the absorbent core in the thickness direction, and a non-skin-side core wrap sheet located on the non-skin side of the absorbent core in the thickness direction, wherein the skin-side core wrap sheet and the non-skin-side core wrap sheet are made of crepe paper having an unevenness, and the degree of unevenness of the skin-side core wrap sheet is smaller than the degree of unevenness of the non-skin-side core wrap sheet.

[0008] Another aspect of the present invention is a method for manufacturing an absorbent article having a longitudinal direction, a width direction and a thickness direction perpendicular to each other, the absorbent article comprising a top sheet, a back sheet and an absorbent body located between the top sheet and the back sheet, the absorbent body comprising an absorbent core containing pulp fibers, a skin-side core wrap sheet located on the skin side of the absorbent core in the thickness direction, and a non-skin-side core wrap sheet located on the non-skin side of the absorbent core in the thickness direction, the method comprising the steps of: forming a continuous top sheet from the top sheet; a continuous skin-side core wrap sheet from the skin-side core wrap sheet formed of crepe paper having unevenness; a continuous non-skin-side core wrap sheet from the non-skin-side core wrap sheet formed of crepe paper having unevenness; a continuous back sheet from the back sheet; and a forming step of forming a laminate in which a surface sheet portion of the continuous surface sheet, a skin side core wrap sheet portion of the continuous skin side core wrap sheet, the absorbent core, a non-skin side core wrap sheet portion of the continuous non-skin side core wrap sheet, and a back sheet portion of the continuous back sheet are stacked in this order, wherein the forming step includes a coating step of applying a composition containing a hydrophilic solvent to at least one of the surface sheet portion of the continuous surface sheet and the skin side core wrap sheet portion of the continuous skin side core wrap sheet, and the degree of unevenness of the skin side core wrap sheet portion of the continuous skin side core wrap sheet after the forming step is smaller than the degree of unevenness of the non-skin side core wrap sheet portion of the continuous non-skin side core wrap sheet. Effect of the Invention

[0009] According to the present invention, an absorbent article and a manufacturing method thereof can be provided which have an absorbent body including an absorbent core wrapped in a core wrap sheet of crepe paper, and which is capable of achieving both improved rewetting by improving the liquid diffusion in the planar direction in the core wrap sheet and suppressing breakage of the core wrap sheet. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view showing an example of a configuration of a disposable diaper according to an embodiment in an unfolded state. [Diagram 2] FIG. 2 is a bottom view showing an example of the configuration of a disposable diaper according to an embodiment in an unfolded state. [Diagram 3] FIG. 2 is a cross-sectional view taken along the line CW-CW in FIG. [Figure 4] FIG. 2 is a plan view showing a configuration example of an absorbent body according to an embodiment. [Diagram 5] 1A to 1C are schematic diagrams illustrating an example of a manufacturing method for an absorbent article according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present disclosure relates to the following aspects: [Aspect 1] An absorbent article having a longitudinal direction, a width direction and a thickness direction which are perpendicular to each other, and comprising a top sheet, a back sheet and an absorbent body located between the top sheet and the back sheet, wherein the absorbent body includes an absorbent core containing pulp fibers, a skin side core wrap sheet located on the skin side of the absorbent core in the thickness direction, and a non-skin side core wrap sheet located on the non-skin side of the absorbent core in the thickness direction, wherein the skin side core wrap sheet and the non-skin side core wrap sheet are made of crepe paper having unevenness, and the degree of unevenness of the skin side core wrap sheet is smaller than the degree of unevenness of the non-skin side core wrap sheet.

[0012] In the present absorbent article, the degree of unevenness (number of wrinkles and / or size of wrinkles) of the skin-side core wrap sheet made of uneven crepe paper is smaller than the degree of unevenness of the non-skin-side core wrap sheet. That is, in the present absorbent article, the degree of unevenness of the skin-side core wrap sheet is relatively small. This can improve the liquid diffusibility in the planar direction of the skin-side core wrap sheet, and further increase the contact area between the top sheet and the skin-side core wrap sheet and the contact area between the skin-side core wrap sheet and the absorbent core. Therefore, during use, body fluids (including sweat) discharged into the absorbent article and transferred from the top sheet to the skin-side core wrap sheet can be diffused in the planar direction of the skin-side core wrap sheet and then transferred to the absorbent core. Therefore, the body fluids can be absorbed in a very wide area in the absorbent body, so that the amount of body fluid absorbed per unit area in the plan view of the absorbent body can be reduced. This can make the absorbent article less susceptible to rewetting after absorbing body fluid. On the other hand, by relatively increasing the unevenness of the non-skin-side core wrap sheet of crepe paper, the non-skin-side core wrap sheet can be easily deformed. As a result, even if the absorbent article expands and contracts due to the wearer's body movement during use, the non-skin-side core wrap sheet can follow the expansion and contraction, and breakage can be suppressed. At that time, the unevenness of the non-skin-side core wrap sheet absorbs the external force caused by the body movement, so the external force acting on the skin-side core wrap sheet (which has a small unevenness and cannot be said to be large in terms of the allowable external force) is reduced, and breakage of the skin-side core wrap sheet can also be suppressed. In this way, in an absorbent article having an absorbent body including an absorbent core wrapped in a crepe paper core wrap sheet, it is possible to achieve both improved rewetting due to improved liquid diffusion in the planar direction of the skin-side core wrap sheet and suppression of breakage of the core wrap sheet.

[0013] [Aspect 2] The absorbent article of claim 1, wherein the skin side core wrap sheet comprises fibers constituting the skin side core wrap sheet and a composition containing a hydrophilic solvent supported on the fibers.

[0014] In this absorbent article, the fibers constituting the skin-side core wrap sheet carry a composition containing a hydrophilic solvent (which may be water), and the effect of the hydrophilic solvent makes the fibers more compatible with body fluids. Therefore, during use, body fluid released into the absorbent article and transferred from the top sheet to the skin-side core wrap sheet can be more diffused in the planar direction of the skin-side core wrap sheet. In other words, the liquid diffusion in the planar direction of the skin-side core wrap sheet can be further improved. This can further suppress rewetting of the absorbent article.

[0015] [Aspect 3] The absorbent article of embodiment 2, wherein the composition further comprises a hydrophilic antimicrobial agent.

[0016] In this absorbent article, the fibers constituting the skin-side core wrap sheet are supported with a composition further including a hydrophilic antibacterial agent. The effect of the hydrophilic antibacterial agent makes the fibers more compatible with body fluids. Therefore, during use, body fluids released into the absorbent article and transferred from the top sheet to the skin-side core wrap sheet can be more diffused in the planar direction of the skin-side core wrap sheet. In other words, the liquid diffusibility in the planar direction of the skin-side core wrap sheet can be further improved. This can further suppress rewetting of the absorbent article. Furthermore, the antibacterial agent can impart antibacterial properties to body fluids transferring from the top sheet to the absorbent body.

[0017] [Aspect 4] 4. The absorbent article of claim 3, wherein the solvent comprises a non-volatile organic material.

[0018] In this absorbent article, the fibers constituting the skin-side core wrap sheet carry a solvent containing a hydrophilic and non-volatile organic substance. The effect of the hydrophilic and non-volatile organic substance allows the compatibility of the body fluid with the fibers to be stably and continuously exhibited. Therefore, during use, the body fluid released into the absorbent article and transferred from the top sheet to the skin-side core wrap sheet can be further diffused in the planar direction of the skin-side core wrap sheet. In other words, the liquid diffusion in the planar direction of the skin-side core wrap sheet can be further improved. This makes it possible to further suppress rewetting of the absorbent article. Furthermore, since the hydrophilic and non-volatile organic substance is difficult to volatilize, irritation to the skin can be suppressed.

[0019] [Aspect 5] An absorbent article as described in aspect 1 or 2, wherein the degree of unevenness in the center of the longitudinal direction and the center of the width direction of the skin side core wrap sheet is smaller than the degree of unevenness at both ends of the longitudinal direction and both ends of the width direction.

[0020] In the absorbent article, the degree of unevenness in the longitudinal center and width center of the skin-side core wrap sheet, i.e., the region where bodily fluid is discharged (hereinafter also referred to as the "excretion opening contact region"), is relatively small. Therefore, the planar liquid diffusibility of the skin-side core wrap sheet in the excretion opening contact region can be relatively large. As a result, in the skin-side core wrap sheet, during use, bodily fluid discharged to the excretion opening contact region can be diffused more quickly in the planar direction and then transferred to the absorbent core. Therefore, bodily fluid can be absorbed in a very wide region within the absorbent body, and the absorbent article can be made less susceptible to rewetting. Furthermore, the degree of unevenness in the longitudinal and width ends of the skin-side core wrap sheet, i.e., the end regions of the absorbent body (hereinafter also referred to as the "end regions"), is relatively large. Therefore, the planar liquid diffusibility of the skin-side core wrap sheet in the end regions can be relatively small. This makes it possible to suppress the diffusion of bodily fluids that have diffused outward from the excretion opening contact area in the end region during use, and therefore to suppress leakage of bodily fluids out of the absorbent article in the end region during use.

[0021] [Aspect 6] 3. The absorbent article of claim 1 or 2, wherein the unevenness of the skin side core wrap sheet is smaller than the unevenness of the skin side of the top sheet.

[0022] In this absorbent article, the unevenness of the skin-side core wrap sheet is made smaller than the unevenness of the skin-side of the topsheet, so that the skin-side core wrap sheet can easily come into contact with the topsheet. As a result, during use, bodily fluids released onto the topsheet can be quickly transferred from the topsheet to the skin-side core wrap sheet, and can be diffused in the planar direction by the skin-side core wrap sheet before being transferred to the absorbent core. Furthermore, by relatively increasing the unevenness of the skin-side of the topsheet, bodily fluids absorbed into the absorbent core can be made less likely to come into contact with the wearer's skin through the topsheet, making rewetting less likely to occur.

[0023] [Aspect 7] An absorbent article as described in aspect 1 or 2, wherein the crepe paper in the skin side core wrap sheet and the non-skin side core wrap sheet has a concave surface on the side opposite to the convex portion of the unevenness, and the concave portion includes a portion of the pulp fibers of the absorbent core.

[0024] In this absorbent article, the crepe paper in the skin-side core wrap sheet includes a part of the pulp fibers of the absorbent core in the concave portion on the surface opposite to the convex portion. This increases the contact area between the skin-side core wrap sheet and the absorbent core. This allows body fluid discharged into the absorbent article during use to be quickly transferred from the skin-side core wrap sheet to the absorbent core. Furthermore, the crepe paper in the non-skin-side core wrap sheet includes a part of the pulp fibers of the absorbent core in the concave portion on the surface opposite to the convex portion. This makes it easier to diffuse body fluid that has not been absorbed by the absorbent core and has passed through in the planar direction, and allows it to be absorbed by the absorbent core on the end side in the longitudinal direction and / or width direction. Furthermore, by having the concave portion on the surface opposite to the convex portion include the pulp fibers, it is possible to prevent the skin-side core wrap sheet and the non-skin-side core wrap sheet from being deformed too much, which reduces the absorption performance.

[0025] [Aspect 8] The absorbent article of aspect 1 or 2, further comprising a non-skin-side elastic member extending along the longitudinal direction at a position overlapping with the absorbent in the thickness direction and on the non-skin side of the absorbent in the thickness direction.

[0026] The absorbent article includes a non-skin-side elastic member extending in the longitudinal direction at a position overlapping the absorbent body in the thickness direction and on the non-skin side of the absorbent body in the thickness direction, which makes it easier to press the skin side portion of the absorbent body against the body. This allows bodily fluids released into the absorbent article to be transferred more quickly from the top sheet to the absorbent body during use. Furthermore, the non-skin-side elastic member can reinforce the non-skin-side core wrap sheet, which further prevents the non-skin-side core wrap sheet from breaking.

[0027] [Aspect 9] An absorbent article as described in aspect 8, further comprising a pair of leakproof walls located on both sides of the top sheet in the width direction and extending along the longitudinal direction, each of the pair of leakproof walls including a leakproof elastic member extending along the longitudinal direction, and the contractile force per unit length of the leakproof elastic member being smaller than the contractile force per unit length of the non-skin-side elastic member.

[0028] In this absorbent article, a pair of leak-proof walls located on both sides of the width of the top sheet and extending along the longitudinal direction each further includes a leak-proof elastic member extending along the longitudinal direction, thereby preventing lateral leakage of body fluids in the width direction. In addition, a non-skin-side elastic member having a contractile force per unit length greater than that of the leak-proof elastic member is provided on the non-skin side, making it easier to press the skin-side portion of the absorbent body against the body. This prevents lateral leakage of body fluids discharged into the absorbent article during use, while allowing the body fluids to be transferred more quickly from the top sheet to the absorbent body.

[0029] [Aspect 10] An absorbent article as described in aspect 1 or 2, having a pair of embossed portions formed in a groove shape extending from the surface of the top sheet toward the absorbent body and extending along the longitudinal direction, and the degree of unevenness of the skin side core wrap sheet in the area between the pair of embossed portions is smaller than the degree of unevenness of the skin side core wrap sheet in areas located widthwise outside each of the pair of embossed portions.

[0030] In this absorbent article, the unevenness of the skin-side core wrap sheet in the region between the pair of embossed portions (hereinafter also referred to as the "inner region") is relatively small. Therefore, the liquid diffusibility in the planar direction of the skin-side core wrap sheet in the inner region can be relatively large. As a result, in the skin-side core wrap sheet, during use, body fluid discharged to the inner region can be diffused in the planar direction more quickly and then transferred to the absorbent core. Therefore, body fluid can be absorbed in a very wide region in the absorbent body, and rewetting of the absorbent article can be prevented. Furthermore, the unevenness of the skin-side core wrap sheet in the region located outside each of the pair of embossed portions in the width direction (hereinafter also referred to as the "outer region") is relatively large. Therefore, the liquid diffusibility in the planar direction of the skin-side core wrap sheet in the outer region can be relatively small. As a result, during use, the diffusion of body fluid diffused from the inner region toward the outside (over the embossed portions) can be suppressed in the outer region, while the body fluid can be transferred to the absorbent core. Therefore, during use, leakage of bodily fluids out of the absorbent article can be suppressed in the outer region.

[0031] [Aspect 11] A method for manufacturing an absorbent article having a longitudinal direction, a width direction and a thickness direction perpendicular to each other, the absorbent article comprising a top sheet, a back sheet and an absorbent body located between the top sheet and the back sheet, the absorbent body comprising an absorbent core containing pulp fibers, a skin-side core wrap sheet located on the skin side of the absorbent core in the thickness direction, and a non-skin-side core wrap sheet located on the non-skin side of the absorbent core in the thickness direction. The method comprises preparing a continuous top sheet in which the top sheet is continuous, a continuous skin-side core wrap sheet in which the skin-side core wrap sheets are continuous and made of crepe paper having unevenness, a continuous non-skin-side core wrap sheet in which the non-skin-side core wrap sheets are continuous and made of crepe paper having unevenness, a plurality of the absorbent cores, and a continuous back sheet in which the back sheet is continuous. and a forming step of forming a laminate in which a portion of the top sheet of the continuous top sheet, a portion of the skin side core wrap sheet of the continuous skin side core wrap sheet, the absorbent core, a portion of the non-skin side core wrap sheet of the continuous non-skin side core wrap sheet, and a portion of the back sheet of the continuous back sheet are stacked in this order, wherein the forming step includes a coating step of applying a composition containing a hydrophilic solvent to at least one of the portion of the top sheet of the continuous top sheet and the portion of the skin side core wrap sheet of the continuous skin side core wrap sheet, and the degree of unevenness of the portion of the skin side core wrap sheet in the continuous skin side core wrap sheet after the forming step is smaller than the degree of unevenness of the portion of the non-skin side core wrap sheet in the continuous non-skin side core wrap sheet.

[0032] In the manufacturing method of the absorbent article, the unevenness of the skin-side core wrap sheet can be relatively reduced by the composition applied to the top sheet and transferred to the skin-side core wrap sheet in contact with the top sheet, or by the composition applied to the skin-side core wrap sheet. Therefore, the contact area between the top sheet and the skin-side core wrap sheet can be increased. This can increase the stability of the bonding between the top sheet and the skin-side core wrap sheet. At the same time, since the unevenness of the skin-side core wrap sheet of the manufactured absorbent article is relatively small, during use, body fluid (including sweat) discharged to the absorbent article and transferred from the top sheet to the skin-side core wrap sheet can be diffused in the planar direction of the skin-side core wrap sheet and then transferred to the absorbent core. Therefore, body fluid can be absorbed in a very wide area within the absorbent body, so the amount of body fluid absorbed per unit area in a plan view of the absorbent body can be reduced. This can make the absorbent article less susceptible to rewetting after absorbing body fluid. In addition, by relatively increasing the degree of unevenness of the non-skin side core wrap sheet of crepe paper, the non-skin side core wrap sheet can be made easier to deform, thereby preventing the non-skin side core wrap sheet or the skin side core wrap sheet from breaking during use.

[0033] [Aspect 12] The method described in aspect 11, wherein in the application step, the composition is applied only to the longitudinal and widthwise central portions of the surface sheet portion of the continuous surface sheet, and only to the longitudinal and widthwise central portions of the skin side core wrap sheet portion of the continuous skin side core wrap sheet.

[0034] In the manufacturing method of the absorbent article, the composition is applied to the longitudinal and widthwise central portion of the top sheet or the skin side core wrap sheet, i.e., the excretion opening contact area. This makes it possible to relatively reduce the degree of unevenness in the skin side core wrap sheet. Therefore, the contact area between the top sheet and the skin side core wrap sheet in the excretion opening contact area can be made larger. This makes it possible to further increase the stability of the bond between the top sheet and the skin side core wrap sheet in the excretion opening contact area. Furthermore, the composition is not applied to the end portions of the top sheet or the skin side core wrap sheet other than the longitudinal and widthwise central portions. In this way, by not applying the composition to the longitudinal and widthwise ends where the adhesive is mainly disposed when the sheets are bonded together, the adhesive can function properly at the ends. This makes it possible to suppress the occurrence of problems such as the adhesive not functioning well during transportation, causing the sheets at the ends of the absorbent article to turn over.

[0035] [Aspect 13] A method as described in aspect 11 or 12, wherein in the application step, the composition is applied, when viewed in a planar view, only within the area of ​​the continuous top sheet where the absorbent core is located, and only within the area of ​​the continuous skin-side core wrap sheet where the absorbent core is located.

[0036] In the method for manufacturing an absorbent article, the composition is applied only to the area of ​​the top sheet or the skin-side core wrap sheet where the absorbent core is disposed in a plan view. By limiting the area to which the composition is applied, the composition can be prevented from diffusing from the skin-side core wrap sheet to the non-skin-side core wrap sheet even if the skin-side core wrap sheet is joined to the non-skin-side core wrap sheet outside the area where the absorbent core is disposed. This can prevent the unevenness of the non-skin-side core wrap sheet from decreasing and the adhesive from becoming difficult to function when the sheets are joined together.

[0037] [Aspect 14] 13. The method of claim 11 or 12, wherein the composition further comprises a hydrophilic antimicrobial agent, and the solvent comprises water and an organic solvent, wherein the amount of water in the solvent is less than the amount of the organic solvent.

[0038] In the method for producing an absorbent article, the composition further contains a hydrophilic antibacterial agent, the solvent contains water and an organic solvent, and the amount of water is less than the amount of the organic solvent. In this way, by reducing the ratio of water in the composition, it is possible to suppress the occurrence of rust in the production equipment. On the other hand, by increasing the ratio of the organic solvent in the composition, it is possible to suppress the antibacterial agent itself from being exposed on the surface of the top sheet and irritating the skin of the wearer.

[0039] Hereinafter, the absorbent article and the manufacturing method thereof according to the embodiment will be described using a pants-type disposable diaper (hereinafter, simply referred to as a "disposable diaper") as an example of the absorbent article. However, the type of absorbent article is not limited to this example, and other types of absorbent articles may be used without departing from the scope of the present invention. Examples of such absorbent articles include tape-type diapers, incontinence pads, sanitary napkins, and panty liners.

[0040] First, an absorbent article according to an embodiment will be described. Figs. 1 to 4 are diagrams showing an example of the configuration of a disposable diaper 1 according to an embodiment. Figs. 1 and 2 are plan and bottom views, respectively, showing an example of the configuration of a disposable diaper according to an embodiment in an unfolded state. Fig. 3 is a schematic cross-sectional view taken along line CW-CW in Fig. 1. Fig. 4 is a plan view showing an example of the configuration of an absorbent body according to an embodiment.

[0041] In the unfolded state shown in FIG. 1, the disposable diaper 1 has a longitudinal direction L, a width direction W, and a thickness direction T that are perpendicular to each other, and has a longitudinal center line CL that passes through the center of the width direction W and extends in the longitudinal direction L, and a width direction center line CW that passes through the center of the longitudinal direction L and extends in the width direction W. Here, the direction and side approaching the longitudinal center line CL are respectively referred to as the inward and inner sides of the width direction W, and the direction and side moving away from the longitudinal center line CW are respectively referred to as the outward and outer sides of the width direction W. Meanwhile, the direction and side approaching the width direction center line CW are respectively referred to as the inward and inner sides of the longitudinal direction L, and the direction and side moving away from the width direction center line CW are respectively referred to as the outward and outer sides of the longitudinal direction L. In addition, the side toward the edge (abdominal edge) of the disposable diaper 1 corresponding to the wearer's abdomen in the longitudinal direction L is also referred to as the front side of the longitudinal direction L, and the side toward the edge (back edge) of the disposable diaper 1 corresponding to the wearer's back is also referred to as the rear side of the longitudinal direction L. In addition, "plan view" refers to viewing the disposable diaper 1 in a state of being unfolded on a plane including the longitudinal direction L and the width direction W from above in the thickness direction T, and "planar shape" refers to a shape as understood in a plan view. "Planar direction" refers to any direction parallel to a plane including the width direction W and the longitudinal direction L. "Skin side" and "non-skin side" respectively refer to the side that is relatively closer to the skin surface of the wearer in the thickness direction T when the disposable diaper 1 is worn by a wearer. "A direction along the longitudinal direction L" is not limited to the case where the direction is parallel to the longitudinal direction L, but also includes a range of ±30° with respect to the longitudinal direction L. "A direction along the width direction W" is not limited to the case where the direction is parallel to the width direction W, but also includes a range of ±30° with respect to the width direction W. These definitions are used not only for the disposable diaper 1, but also for the absorbent body of the disposable diaper 1 and each material arranged therein.

[0042] 1, the disposable diaper 1 includes, in the longitudinal direction L, a ventral portion (ventral waist belt) 2 located at the front, a dorsal portion (dorsal waist belt) 3 located at the rear, and an absorbent main body 10 located between the ventral portion 2 and the dorsal portion 3. In this embodiment, the ventral portion 2 has a generally rectangular shape extending in the width direction W, the dorsal portion 3 has a generally rectangular shape extending in the width direction W but with a shape in which the front portion in the longitudinal direction L extends forward, and the absorbent main body 10 has a generally rectangular shape extending in the longitudinal direction L.

[0043] The abdominal portion 2 is a portion that contacts the wearer's abdomen. The back portion 3 is a portion that contacts the wearer's buttocks or back. The absorbent body 10 is a portion that contacts the wearer's crotch (excretory opening). One end of the absorbent body 10 in the longitudinal direction L is laminated and joined to the skin-side surface of the abdominal portion 2, and the other end is laminated and joined to the skin-side surface of the back portion 3. Both ends 2a, 2a in the width direction W of the abdominal portion 2 and both ends 3a, 3a in the width direction W of the back portion 3 overlap in the thickness direction T and are joined along the longitudinal direction L to form a disposable diaper 1. In this case, in the disposable diaper 1, the outer end of the abdominal portion 2 in the longitudinal direction L and the outer end of the back portion 3 in the longitudinal direction L define a waist opening through which the wearer's waist passes. In addition, in the disposable diaper 1, a pair of leg openings through which the wearer's pair of legs pass are defined by both ends in the width direction W of the absorbent body 10, the inner end in the longitudinal direction L of the ventral portion 2, and the inner end in the longitudinal direction L of the dorsal portion 3.

[0044] In this embodiment, in the state shown in Fig. 1, the abdominal portion 2 and the back portion 3 are spaced apart from each other in the longitudinal direction L. That is, the abdominal portion 2 and the back portion 3 are formed separately from each other. In another embodiment, the disposable diaper 1 further includes a crotch portion located between the abdominal portion 2 and the back portion 3, one end of which is connected to the abdominal portion 2 and the other end of which is connected to the back portion 3. In this case, the abdominal portion 2, the back portion 3 and the crotch portion are formed integrally with each other or separately.

[0045] In this embodiment, the abdominal portion 2 includes liquid-impermeable cover sheets 21, 22, and 24. The cover sheet 21 is located on the skin side, and the cover sheet 22 is located on the non-skin side. The cover sheets 21 and 22 are laminated in the thickness direction T and are joined to each other by adhesive or heat fusion. The cover sheet 24 is laminated on the cover sheet 21 so as to cover the front end of the absorbent body 10 in the longitudinal direction L from the skin side. Similarly, in this embodiment, the back portion 3 includes liquid-impermeable cover sheets 31, 32, and 34. The cover sheet 31 is located on the skin side, and the cover sheet 32 ​​is located on the non-skin side. The cover sheets 31 and 32 are laminated in the thickness direction T and are joined to each other by adhesive or heat fusion. The cover sheet 34 is laminated on the cover sheet 31 so as to cover the rear end of the absorbent body 10 in the longitudinal direction L from the skin side. Examples of materials for each cover sheet include liquid-impermeable nonwoven fabrics and synthetic resin films. The types of liquid-impermeable nonwoven fabrics and synthetic resin films and their materials will be described later. At least one of the cover sheets 24 and 34 may be omitted. Each cover sheet may be made up of multiple sheets.

[0046] In this embodiment, the abdominal portion 2 includes a plurality of elastic members 23 for waist gathering between the cover sheet 21 and the cover sheet 22. The plurality of elastic members 23 extend along the width direction W, are arranged in the abdominal portion 2 at intervals in the longitudinal direction L, and are joined to the cover sheet 21 and the cover sheet 22 by adhesive or heat fusion. The elastic members 23 may not be arranged in the region of the abdominal portion 2 that is located on the non-skin side of the absorbent main body 10. Similarly, in this embodiment, the back portion 3 includes a plurality of elastic members 33 for waist gathering between the cover sheet 31 and the cover sheet 32. The plurality of elastic members 33 extend along the width direction W, are arranged in the abdominal portion 2 at intervals in the longitudinal direction L, and are joined to the cover sheet 31 and the cover sheet 32 ​​by adhesive or heat fusion. The elastic members 33 may not be arranged in the region of the back portion 3 that is located on the non-skin side of the absorbent main body 10. In this embodiment, the back side portion 3 further includes a plurality of elastic members 35 for leg gathers between the cover sheet 31 and the cover sheet 32. The plurality of elastic members 35 are arranged on the inside in the longitudinal direction L of the elastic members 33 so as to be convex toward the abdominal side portion 2 in a plan view. An example of the material of each elastic member is rubber thread.

[0047] In this embodiment, the absorbent body 10 includes a liquid-permeable top sheet 12, a liquid-impermeable back sheet 13, and an absorbent body 11 located between the top sheet 12 and the back sheet 13 and absorbing and retaining liquid. Examples of materials for the top sheet 12 include liquid-permeable nonwoven fabrics or woven fabrics, synthetic resin films with liquid-permeable holes, and combinations of the same or different types of these. Examples of materials for the back sheet 13 include liquid-impermeable and breathable nonwoven fabrics, synthetic resin films with air holes, and combinations of the same or different types of these. In addition, a liquid-permeable diffusion sheet located between the top sheet 12 and the absorbent body 11 and diffusing liquid in the planar direction may be provided.

[0048] Examples of the top sheet 12 include a flat sheet without any irregularities, a sheet extending in the longitudinal direction L and having a plurality of convex portions spaced apart in the width direction W and a plurality of concave portions provided between each of the plurality of convex portions, and a sheet having a plurality of convex portions that are approximately circular in plan view and arranged in a checkerboard pattern in plan view.

[0049] The type of liquid-permeable or liquid-impermeable nonwoven fabric is not particularly limited as long as it can be used for absorbent articles, and examples thereof include meltblown nonwoven fabric, spunbond nonwoven fabric, airlaid nonwoven fabric, and air-through nonwoven fabric. The material of the nonwoven fabric is not particularly limited as long as it can be used for absorbent articles, and examples thereof include synthetic resin fibers and pulp fibers. The synthetic resin is not particularly limited as long as it can be used for absorbent articles, and examples thereof include olefin resins such as polyethylene and polypropylene, polyamide resins such as 6-nylon and 6,6-nylon, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate. Pulp fibers will be described later. The type of liquid-permeable or liquid-impermeable synthetic resin film is not particularly limited as long as it can be used for absorbent articles, and examples thereof include known film materials. The material of the synthetic resin film is not particularly limited as long as it can be used for absorbent articles, and examples thereof include the synthetic resins described above.

[0050] The absorbent body 11 includes an absorbent core 11a that absorbs and retains liquid, and a core wrap sheet 11b that encases the absorbent core 11a. The material of the absorbent core 11a includes absorbent materials, such as pulp fibers and superabsorbent polymers. Examples of pulp fibers include cellulosic fibers. Examples of cellulosic fibers include wood pulp, crosslinked pulp, non-wood pulp, regenerated cellulose, and semi-synthetic cellulose. Examples of superabsorbent polymers (SAP) include polyacrylate-based, polysulfonate-based, and maleic anhydride-based water-absorbent polymers. Examples of the material of the core wrap sheet 11b include liquid-permeable nonwoven fabrics (including tissues) made of synthetic resin fibers or pulp fibers, and composite sheets thereof. There are no particular limitations on the type of synthetic resin fiber as long as it can be used for absorbent articles, and examples of the fiber include known synthetic fibers. The types of nonwoven fabrics, synthetic resins, and pulp fibers are as described above. The absorbent body 11 will be described in detail later.

[0051] The absorbent body 11 and the top sheet 12, and the absorbent body 11 and the back sheet 13 are bonded to each other with an adhesive. The top sheet 12 and the back sheet 13 are bonded to each other at their peripheral portions with an adhesive. The adhesive may be, for example, a hot melt adhesive. The shape of the absorbent body 10 is not limited to the above example as long as it is long in the longitudinal direction L, and may be, for example, a rectangle with rounded corners, a rectangle with short sides curved outward, or an hourglass shape.

[0052] The basis weights of the top sheet 12, the back sheet 13, and the absorbent body 11 are appropriately adjusted according to the absorption performance required for the disposable diaper 1, but are not particularly limited as long as they can be used as sheets for the disposable diaper 1. The basis weight of the top sheet 12 is, for example, 5 to 200 g / m 2 The basis weight of the back sheet 13 is, for example, 5 to 200 g / m 2 The basis weight of the absorbent core 11a is, for example, 10 to 2000 g / m 2The basis weight of the core wrap sheet 11b is, for example, 5 to 100 g / m 2 Some examples include:

[0053] The average fiber diameter (diameter) of the fibers constituting the core wrap sheet 11b is not particularly limited as long as it can be used as each sheet of the disposable diaper 1. The average fiber diameter of these fibers is, for example, 5 to 100 μm, and preferably 10 to 50 μm. By setting the average fiber diameter to 5 μm or more, the fibers do not become too thin, and for example, a liquid composition applied to the core wrap sheet 11b is less likely to move (or fall) vertically downward from the fibers due to gravity. By setting the average fiber diameter to 100 μm or less, the fibers do not become too thick, and for example, the surface area per volume of the fibers can be increased, making it easier to hold a large amount of liquid composition.

[0054] In this embodiment, the absorbent body 10 further includes an exterior sheet 14 laminated on the non-skin side of the back sheet 13. In the exterior sheet 14, both sides in the width direction W wrap around to the skin side of the laminate of the top sheet 12, the absorbent body 11, and the back sheet 13 to form a pair of leak-proof walls 15 extending in the longitudinal direction L. The outer edge of each leak-proof wall 15 in the width direction W is fixed to the edge of the absorbent body 10 in the width direction W, and the inner edge in the width direction W is not fixed. The leak-proof walls 15 are fixed by covering both ends in the longitudinal direction L with the cover sheets 24 and 34. Examples of materials for the exterior sheet 14 and the leak-proof walls 15 include hydrophobic sheets such as hydrophobic nonwoven fabrics. In another embodiment, examples of materials for the exterior sheet 14 and the leak-proof walls 15 include hydrophilic sheets such as hydrophilic nonwoven fabrics. Each leak-preventing wall 15 includes two leak-preventing elastic members 16 extending along the longitudinal direction L at its inner end in the width direction W. The leak-preventing elastic members 16 are exemplified by rubber threads. In another embodiment, each of the pair of leak-preventing walls 15 has its inner end in the width direction W further folded back toward the outside in the width direction W. In another embodiment, the number of leak-preventing elastic members 16 is one, or three or more.

[0055] In this embodiment, the absorbent main body 10 further includes one or more non-skin side elastic members 17 and one or more non-skin side elastic members 18 between the back sheet 13 and the exterior sheet 14 at a position overlapping with the absorber 11 in the thickness direction T. The non-skin side elastic members 17 extend along the longitudinal direction L at both ends of the absorbent main body 10 in the width direction W. The non-skin side elastic members 17 are for leg gathers. On the other hand, the non-skin side elastic members 18 extend along the longitudinal direction L from the rear end in the longitudinal direction L to near the central portion at the center of the absorbent main body 10 in the width direction W. The non-skin side elastic members 18 are used to press the rear (back) portion of the absorbent main body 10 in the longitudinal direction L against the buttocks or back of the wearer. An example of the material of each non-skin side elastic member is rubber thread.

[0056] Next, the absorbent body 11 will be described. The absorbent body 11 is a layer having liquid absorption and liquid retention properties. In this embodiment, the absorbent body 11 has a single layer structure. In another embodiment, the absorbent body 11 has a two-layer structure having an upper layer and a lower layer. In that case, the lengths of the upper layer and the lower layer in the width direction W and the length direction L may be the same or different, and the amount and type of absorbent material may be different. In another embodiment, the absorbent body 11 has a multi-layer structure having three or more layers.

[0057] The shape of the absorbent 11 (and core wrap sheet 11b) in a plan view is not particularly limited as long as it is a shape extending in the longitudinal direction L. In this embodiment, the absorbent 11 (and core wrap sheet 11b) has a rectangular shape extending in the longitudinal direction L. However, the shape is not limited to this example, and examples include a rectangle with a short side protruding in an arc shape, a rectangle with rounded corners, an ellipse, and an hourglass shape. The length (thickness) of the absorbent 11 in the thickness direction T is, for example, 0.5 to 20 mm, the length (length) in the longitudinal direction L is, for example, 15 to 40 cm, and the length (width) in the width direction W is, for example, 5 to 15 cm.

[0058] The shape of the absorbent core 11a in a plan view is not particularly limited as long as it extends in the longitudinal direction L and fits within the core wrap sheet 11b. In this embodiment, the absorbent body 11 has a generally hourglass shape with the center part in the longitudinal direction L narrowed inward. However, the shape is not limited to this example, and examples include a rectangle with short sides protruding in an arc shape, a rectangle with rounded corners, and an ellipse.

[0059] The core wrap sheet 11b includes a skin-side core wrap sheet 11b1 arranged on the skin side of the absorbent core 11a in the thickness direction T, and a non-skin-side core wrap sheet 11b2 arranged on the non-skin side of the absorbent core 11a in the thickness direction T. In this embodiment, the skin-side core wrap sheet 11b1 and the non-skin-side core wrap sheet 11b2 are integrally formed, that is, formed from a single sheet. Then, both ends in the width direction W of the single sheet are joined to each other to form a tube, the absorbent core 11a is contained inside, and both ends in the longitudinal direction L are sealed to form the absorbent body 11. In this case, the skin side of the absorbent core 11a is the skin-side core wrap sheet 11b1, and the non-skin side is the non-skin side core wrap sheet 11b2. In another embodiment, the skin-side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2 are formed separately from each other. Furthermore, in another embodiment, at least one of the skin side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2 is formed of multiple sheets.

[0060] The skin side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2 are made of crepe paper. The crepe paper is a nonwoven fabric (including paper) made of synthetic resin fibers or pulp fibers that has been creped, and has an uneven structure with concaves and convexities composed of multiple wrinkles. The unevenness of the skin side core wrap sheet 11b1 is smaller than that of the non-skin side core wrap sheet 11b2. Here, the unevenness refers to the number of concaves and convexities (wrinkles) per unit length in a direction (e.g., width direction W) perpendicular to the direction in which the concaves and convexities (wrinkles) extend (e.g., longitudinal direction L). The size of the concaves and convexities refers to the height H of the concaves and convexities and / or the width D of the concaves and convexities, as shown in FIG. 3(b). However, the height H of the unevenness refers to the height from the bottom of the recess (the portion between adjacent protrusions 51) to the top of the protrusion 51. The width D of the unevenness refers to the distance between the tops of adjacent protrusions 51 or the distance between the bottoms of adjacent recesses. A small degree of unevenness refers to a small number of unevennesses, a low height H of the unevennesses, and / or a large width D of the unevennesses, and does not include a case where there are no unevennesses. This is to maintain a certain degree of ease of deformation on the skin side of the absorbent body 11. The method for measuring the degree of unevenness of the core wrap sheet will be described later.

[0061] The unevenness of the crepe paper can be adjusted by the crepe processing conditions, the application of liquid to the crepe paper, etc. For example, when liquid is applied to the crepe paper, the applied portion becomes soft by being soaked in the liquid, and the unevenness is easily reduced. This makes it possible to reduce the unevenness. In this case, from the viewpoint of easily maintaining affinity with body fluids and the unevenness, it is preferable that the liquid applied to the crepe paper is hydrophilic and non-volatile.

[0062] In this embodiment, the degree of unevenness does not need to be smaller across the entire surface of the skin side core wrap sheet 11b1 than that of the non-skin side core wrap sheet 11b2. Examples of portions with a smaller degree of unevenness include, in a plan view, the central portion (one portion) excluding both ends (one portion each) when the skin side core wrap sheet 11b1 is divided into three in the width direction W, the central portion (two portions) excluding both ends (one portion each) when the skin side core wrap sheet 11b1 is divided into four in the width direction W, and the central portion (three or one portion) excluding both ends (one or two portions each) when the skin side core wrap sheet 11b1 is divided into five in the width direction W. And / or examples of the parts with a small degree of unevenness include, for example, the central portion (one piece) of the entire surface of the skin side core wrap sheet 11b1 when viewed in a plane, excluding both ends (one piece each) when the skin side core wrap sheet 11b1 is divided into three in the longitudinal direction L, the central portion (two pieces) excluding both ends (one piece each) when the skin side core wrap sheet 11b1 is divided into four in the longitudinal direction L, and the central portion (three pieces) excluding both ends (one piece each) when the skin side core wrap sheet 11b1 is divided into five in the longitudinal direction L.

[0063] In another embodiment, the portion with the above-mentioned small degree of unevenness may be, for example, 20% or more of the entire surface of the skin side core wrap sheet 11b1 when viewed in a plane, including the center in the longitudinal direction L and the width direction W (the intersection of the longitudinal center line CL and the width direction center line CW), preferably 40% or more, and more preferably 60% or more.

[0064] In any of the above cases, the portion with a small degree of unevenness preferably includes an excretory outlet contact area in plan view, and is preferably a region overlapping with the absorbent core 11a. The excretory outlet contact area is a region that faces or contacts the wearer's excretory outlet when the absorbent article (including the disposable diaper 1) is in use. The excretory outlet contact area is appropriately set according to the type and use of the absorbent article. For example, the excretory outlet contact area is set at the center or slightly forward of the center of the absorbent body in the longitudinal direction L, with a length of about 1 / 10 to 1 / 2 of the total length of the absorbent body, and at approximately the center of the absorbent body in the width direction W, with a width of about 1 / 3 to 1 / 2 of the total width of the absorbent body.

[0065] In this embodiment, the skin side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2 encase the absorbent core 11a such that the unevenness and wrinkles of the crepe paper extend along the longitudinal direction L. However, each of the skin side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2 does not need to have unevenness or wrinkles over its entire surface. It is sufficient that 90% or more of the entire surface of each of the skin side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2, including the excretion opening contact area, preferably 95% or more, more preferably 98% or more of the entire surface of the skin side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2 has unevenness and wrinkles. This makes it easier to prevent breakage due to external force in each of the skin side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2.

[0066] In the disposable diaper 1 described above, the unevenness (number of unevenness and / or size of unevenness) of the skin-side core wrap sheet 11b1 made of uneven crepe paper is smaller than the unevenness of the non-skin-side core wrap sheet 11b2. That is, in the disposable diaper 1, the unevenness of the skin-side core wrap sheet 11b1 is relatively small. This can improve the liquid diffusibility in the planar direction of the skin-side core wrap sheet 11b1, and can also increase the contact area between the top sheet 12 and the skin-side core wrap sheet 11b1 and the contact area between the skin-side core wrap sheet 11b1 and the absorbent core 11a. Therefore, during use, bodily fluids (including sweat) discharged into the disposable diaper 1 and transferred from the top sheet 12 to the skin-side core wrap sheet 11b1 can be diffused in the planar direction of the skin-side core wrap sheet 11b1 and then transferred to the absorbent core 11a. Therefore, bodily fluids can be absorbed over a very wide area within the absorbent body 11, thereby reducing the amount of bodily fluids absorbed per unit area in a plan view of the absorbent body 11. This makes it possible to make the disposable diaper 1 less susceptible to rewetting after absorbing bodily fluids.

[0067] On the other hand, by relatively increasing the unevenness of the non-skin side core wrap sheet 11b2 made of crepe paper, the non-skin side core wrap sheet 11b2 can be easily deformed. As a result, even if the disposable diaper 1 expands and contracts due to the wearer's body movements during use, the non-skin side core wrap sheet 11b2 can follow the expansion and contraction, and breakage can be suppressed. At that time, the unevenness of the non-skin side core wrap sheet 11b2 absorbs the external force caused by the wearer's body movements, so the external force acting on the skin side core wrap sheet 11b1 (which has a small unevenness and cannot be said to be large in terms of the allowable external force) is reduced, and breakage of the skin side core wrap sheet 11b1 can also be suppressed.

[0068] In this way, in a disposable diaper 1 having an absorbent body 11 including an absorbent core 11a wrapped in a crepe paper core wrap sheet 11b, it is possible to achieve both improved rewetting by improving the liquid diffusion in the planar direction of the skin-side core wrap sheet 11b1 and suppression of breakage of the core wrap sheet 11b.

[0069] In this embodiment, in the skin side core wrap sheet 11b1, the number of irregularities per unit length in the direction perpendicular to the direction in which the irregularities (wrinkles) extend, i.e., the number (average) of irregularities extending along the longitudinal direction L per unit length of 1 cm in the width direction W, is, for example, 1 to 50. Having one or more irregularities makes it easier for the skin side core wrap sheet 11b1 to deform, and prevents the skin side core wrap sheet 11b1 from breaking. Having 50 or less irregularities improves the liquid diffusibility in the planar direction of the skin side core wrap sheet 11b1, and increases the contact area with both the top sheet 12 and the absorbent core 11a.

[0070] In this embodiment, the skin side core wrap sheet 11b1 has an irregularity height H (average), which is the size of the irregularities (wrinkles), of, for example, 0.1 to 1 mm. When the irregularity height H is 0.1 mm or more, the skin side core wrap sheet 11b1 can be easily deformed, and the breakage of the skin side core wrap sheet 11b1 can be suppressed. When the irregularity height H is 1 mm or less, the liquid diffusibility in the planar direction of the skin side core wrap sheet 11b1 can be improved, and the contact area with both the top sheet 12 and the absorbent core 11a can be increased. In addition, the irregularity width D (average), which is the size of the irregularities, can be, for example, 0.2 to 10 mm. When the irregularity width D is 0.2 mm or more, the skin side core wrap sheet 11b1 can be easily deformed, and the breakage of the skin side core wrap sheet 11b1 can be suppressed. By making the width D of the irregularities 10 mm or less, the liquid diffusibility in the planar direction of the skin side core wrap sheet 11b1 can be improved, and the contact areas with both the top sheet 12 and the absorbent core 11a can be increased.

[0071] In this embodiment, the non-skin side core wrap sheet 11b2 has, for example, 2 to 100 (average) number of irregularities (wrinkles) extending along the longitudinal direction L per unit length of 1 cm in the width direction W. Having two or more irregularities makes it easier for the non-skin side core wrap sheet 11b2 to deform, and prevents breakage of the non-skin side core wrap sheet 11b2 and the skin side core wrap sheet 11b1. Having 100 or less irregularities makes it possible to improve the liquid diffusibility of the non-skin side core wrap sheet 11b2 in the planar direction to a certain extent, and to increase the contact area with both the back sheet 13 and the absorbent core 11a.

[0072] In this embodiment, the non-skin side core wrap sheet 11b2 has an irregularity (wrinkle) height (average), which is the size of the irregularity, of, for example, 0.2 to 2 mm. When the irregularity height H is 0.2 mm or more, the non-skin side core wrap sheet 11b2 can be easily deformed, and breakage of the non-skin side core wrap sheet 11b2 and the skin side core wrap sheet 11b1 can be suppressed. When the irregularity height H is 6 mm or less, the liquid diffusibility in the planar direction of the non-skin side core wrap sheet 11b2 can be improved to a certain extent, and the contact areas with both the back sheet 13 and the absorbent core 11a can be increased. In addition, the irregularity width D (average), which is the size of the irregularity, can be, for example, 0.1 to 5 mm. When the irregularity width D is 0.1 mm or more, the non-skin side core wrap sheet 11b2 can be easily deformed, and breakage of the non-skin side core wrap sheet 11b2 and the skin side core wrap sheet 11b1 can be suppressed. By making the width D of the irregularities 5 mm or less, the liquid diffusibility in the planar direction of the non-skin side core wrap sheet 11b2 can be improved to some extent, and the contact areas with both the back sheet 13 and the absorbent core 11a can be increased.

[0073] In a preferred embodiment of the present invention, the skin side core wrap sheet 11b1 includes fibers constituting the skin side core wrap sheet 11b1 and a composition containing a hydrophilic solvent carried by the fibers. In other words, the skin side core wrap sheet 11b1 includes (is applied to) the composition containing a hydrophilic solvent.

[0074] Here, the fibers constituting the skin side core wrap sheet 11b1 include synthetic resin fibers, pulp fibers, and mixtures thereof, as described above. The composition is a hydrophilic solvent containing a functional agent having a predetermined function. Examples of the functional agent having a predetermined function include antibacterial agents, deodorants, warming agents, herbal medicines, fragrances, and mixtures of at least two of these. The hydrophilic solvent refers to a solvent that is miscible with water in any ratio, and examples of the solvent include water, hydrophilic organic solvents, and mixtures thereof.

[0075] In the disposable diaper 1 as described above, the fibers constituting the skin-side core wrap sheet 11b1 carry a composition containing a hydrophilic solvent, and the hydrophilic solvent can make the fibers more compatible with body fluids. Therefore, during use, body fluid released into the disposable diaper 1 and transferred from the top sheet 12 to the skin-side core wrap sheet 11b1 can be more diffused in the planar direction of the skin-side core wrap sheet 11b1. In other words, the liquid diffusibility in the planar direction of the skin-side core wrap sheet 11b1 can be further improved. This can further suppress rewetting of the disposable diaper 1.

[0076] The fibers constituting the top sheet 12 may carry a composition containing a hydrophilic solvent. In other words, the top sheet 12 may contain (or be coated with) a composition containing a hydrophilic solvent. In this case, the composition of the top sheet 12 migrates over time to the skin side core wrap sheet 11b1, and the same effect as when the composition is disposed on the skin side core wrap sheet 11b1 can be obtained. In this case, the amount of the composition contained in the top sheet 12 is less than the amount of the composition contained in the skin side core wrap sheet 11b1.

[0077] In a preferred aspect of this embodiment, the composition further comprises a hydrophilic antimicrobial agent, in other words, the functional agent included in the composition comprises a hydrophilic antimicrobial agent.

[0078] Here, the hydrophilic antibacterial agent refers to an antibacterial agent that dissolves at least 40 g in 100 g of water at 25° C. within 5 hours. There are no particular limitations on the antibacterial agent, so long as it has hydrophilicity and antibacterial function, that is, the function of suppressing the growth of bacteria. Examples of the type of antibacterial agent include cationic antibacterial agents. Examples of the cationic antibacterial agent include guanidine antibacterial agents, biguanide antibacterial agents, and quaternary ammonium salts. Examples of the guanidine antibacterial agent include polyhexamethylene guanidine (PHMG), and examples of the biguanide antibacterial agent include polyhexamethylene biguanide (PHMB), also known as polyaminopropyl biguanide. Examples of the quaternary ammonium salt include benzalkonium chloride and benzethonium chloride. These antibacterial agents may be used alone or in combination.

[0079] In the disposable diaper 1 as described above, the fibers constituting the skin-side core wrap sheet 11b1 carry a composition further containing a hydrophilic antibacterial agent. The effect of the hydrophilic antibacterial agent can make the fibers more compatible with body fluids. Therefore, during use, the body fluid discharged into the disposable diaper 1 and transferred from the top sheet 12 to the skin-side core wrap sheet 11b1 can be more diffused in the planar direction of the skin-side core wrap sheet 11b1. That is, the liquid diffusibility in the planar direction of the skin-side core wrap sheet 11b1 can be further improved. This can further suppress rewetting of the disposable diaper 1. Furthermore, the antibacterial agent can impart antibacterial properties to the body fluid transferring from the top sheet 12 to the absorbent body 11.

[0080] In a preferred aspect of this embodiment, the solvent contains a non-volatile organic substance, in other words, the solvent contained in the composition contains a hydrophilic and non-volatile organic solvent.

[0081] Here, the non-volatile organic substance (solvent) refers to an organic solvent having a vapor pressure of 50 Pa or less at 25°C. The solvent is not particularly limited as long as it is an organic solvent that is hydrophilic and non-volatile and can dissolve the antibacterial agent. Examples of the solvent include glycols and alcohols. Examples of the glycols include propylene glycol (PG), dipropylene glycol (DPG), 1,3-butylene glycol (BG), and polyethylene glycol 400 (PEG400). Examples of the alcohols include 3-methoxy-3-methyl-1-butanol. These organic solvents may be used alone or in combination.

[0082] In the disposable diaper 1 as described above, the fibers constituting the skin-side core wrap sheet 11b1 carry a solvent containing a hydrophilic and non-volatile organic substance. The effect of the hydrophilic and non-volatile organic substance allows the compatibility of the body fluids with the fibers to be stably and continuously exhibited. Therefore, during use, the body fluid discharged into the disposable diaper 1 and transferred from the top sheet 12 to the skin-side core wrap sheet 11b1 can be diffused further in the planar direction of the skin-side core wrap sheet 11b1. In other words, the liquid diffusibility in the planar direction of the skin-side core wrap sheet 11b1 can be further improved. This can further suppress rewetting of the disposable diaper 1. Furthermore, since the hydrophilic and non-volatile organic substance is difficult to volatilize, irritation to the skin can be suppressed.

[0083] In a preferred embodiment of this embodiment, the composition (including the antibacterial agent and the hydrophilic and non-volatile organic solvent) has a lower limit of viscosity at 25°C of, for example, 5 mPa·s, preferably 50 mPa·s. By setting the lower limit of the viscosity within this range, the composition can be made to remain stable on the surface of the fiber without moving (or falling) vertically downward, and the compatibility of the fiber with body fluids can be more stably and continuously exhibited. From the viewpoint of ease of application, the upper limit is, for example, 12000 mPa·s. The viscosity is measured using a HAAKE RheoStress 1 (sensor: Cone φ60mm, 1° angle C60 / 1) manufactured by Thermo Fisher SCIENTIFIC Co., Ltd. under the conditions of 38 ml of the composition, temperature 25°C, humidity 50%, and shear rate: 10.0 (l / s).

[0084] The lower limit of the total ratio of the antibacterial agent and the solvent to the composition is, for example, 90% by mass, preferably 95% by mass or more, from the viewpoint of ensuring the antibacterial action. The composition may further contain other solvents, such as water, in addition to the antibacterial agent and the organic solvent. In terms of suppressing the volatility of the composition and suppressing rusting of the manufacturing equipment, the amount of water is preferably less than the amount of the organic solvent. In addition, the lower limit of the ratio of the antibacterial agent to the total ratio of the antibacterial agent and the solvent is, for example, 1% by mass, preferably 2% by mass, from the viewpoint of ensuring the antibacterial action. The upper limit is, for example, 60% by mass, preferably 50% by mass, from the viewpoint of dissolution in the solvent. Note that the solvent of the composition can be identified and quantified using GC / MS (gas chromatography mass spectrometry), and the antibacterial agent of the composition can be identified and quantified using LC / MS (high performance liquid chromatography mass spectrometry).

[0085] In a preferred embodiment of the present invention, the degree of unevenness in the center in the longitudinal direction L and the center in the width direction W of the skin side core wrap sheet 11b1 is smaller than the degree of unevenness at both ends in the longitudinal direction L and the width direction W.

[0086] Here, examples of the central portion in the longitudinal direction L of the skin side core wrap sheet 11b1 include, in a plan view, the central portion (one portion) excluding both ends (one portion each) when the skin side core wrap sheet 11b1 is divided into three, preferably into three equal portions, in the longitudinal direction L, the central portion (two portions) excluding both ends (one portion each) when the skin side core wrap sheet 11b1 is divided into four, preferably into four equal portions, in the longitudinal direction L, and the central portion (three or one portion) excluding both ends (one or two portions each) when the skin side core wrap sheet 11b1 is divided into five, preferably into five equal portions, in the longitudinal direction L. The central portion in the longitudinal direction L is appropriately set depending on the performance required of the disposable diaper 1.

[0087] On the other hand, examples of the central portion in the width direction W of the skin side core wrap sheet 11b1 include, in a plan view, the central portion (one portion) excluding both end portions (one portion each) when the skin side core wrap sheet 11b1 is divided into three, preferably equal portions, in the width direction W, the central portion (two portions) excluding both end portions (one portion each) when the skin side core wrap sheet 11b1 is divided into four, preferably equal portions, in the width direction W, and the central portion (three or one portion) excluding both end portions (one or two portions each) when the skin side core wrap sheet 11b1 is divided into five, preferably equal portions, in the width direction W. The above-mentioned central portion in the width direction W is set appropriately depending on the performance required of the disposable diaper 1.

[0088] As shown in FIG. 4, in this embodiment, in the skin side core wrap sheet 11b1, the center in the longitudinal direction L and the center in the width direction W in plan view are also referred to as the central region TA, the outer part thereof is also referred to as the outer region MTA, and the part of the outer region MTA overlapping with the absorbent core 11a is also referred to as the outer central region NTA (note that these definitions are also used for the top sheet 12 and the back sheet 13 overlapping in the thickness direction T). The central region TA in the skin side core wrap sheet 11b1 is a part with a small degree of unevenness, a part including the excretion opening contact area in plan view, and an area overlapping with the absorbent core 11a. In this embodiment, the central region TA is the central part (two parts) when the skin side core wrap sheet 11b1 is divided into four equal parts in the longitudinal direction L and the central part (one part) when the skin side core wrap sheet 11b1 is divided into three equal parts in the width direction W in plan view. The degree of unevenness in the central region TA of the skin side core wrap sheet 11b1 can be reduced in this manner, for example, by applying a composition to the central region TA.

[0089] As described above, in the disposable diaper 1, the degree of unevenness in the center of the longitudinal direction L and the width direction W, i.e., the excretory opening contact area (center area TA), is relatively small in the skin side core wrap sheet 11b1. This allows the liquid diffusibility in the planar direction of the skin side core wrap sheet 11b1 in the excretory opening contact area to be relatively large. This allows the skin side core wrap sheet 11b1 to quickly diffuse body fluid discharged to the excretory opening contact area during use in the planar direction and then transfer the body fluid to the absorbent core 11a. This allows the body fluid to be absorbed in a very wide area (including the outer central area NTA) in the absorbent body 11, which makes it difficult for the disposable diaper 1 to rewet.

[0090] Furthermore, in the disposable diaper 1, the degree of unevenness is relatively large at both ends in the longitudinal direction L and both ends in the width direction W, i.e., at the end regions of the absorbent 11 (hereinafter also referred to as "end regions"). Therefore, the liquid diffusibility in the planar direction of the skin-side core wrap sheet 11b1 in the end regions can be relatively small. This makes it possible to suppress the diffusion of bodily fluids that have been diffused from the excretion opening contact region (central region TA) toward the outside during use in the end regions. Therefore, it is possible to suppress leakage of bodily fluids from the end regions to the outside of the disposable diaper 1 during use. In this embodiment, the end regions are regions outside the central region TA, and are the outer central region NTA or the peripheral regions thereof.

[0091] In a preferred aspect of this embodiment, the unevenness of the skin side core wrap sheet 11b1 is smaller than the unevenness of the skin side of the topsheet 12.

[0092] Here, the top sheet 12 may be a sheet having projections and recesses, for example, a sheet having a plurality of projections extending in the longitudinal direction L and spaced apart in the width direction W, and a plurality of recesses provided between each of the projections, and a sheet having a plurality of projections that are substantially circular in plan view and arranged in a checkerboard pattern in plan view. In this embodiment, the height (average) of the projections and recesses in the top sheet 12 may be, for example, 0.2 to 3 mm. The width D (average) of the projections and recesses may be, for example, 0.1 to 3 mm.

[0093] As described above, in the disposable diaper 1, by making the unevenness of the skin-side core wrap sheet 11b1 relatively smaller than the unevenness of the skin-side of the topsheet 12, the skin-side core wrap sheet 11b1 can be easily brought into contact with the topsheet 12. As a result, during use, bodily fluids discharged onto the topsheet 12 can be quickly transferred from the topsheet 12 to the skin-side core wrap sheet 11b1, and can be diffused in the planar direction by the skin-side core wrap sheet 11b1 before being transferred to the absorbent core 11a. Furthermore, by making the unevenness of the skin-side of the topsheet 12 relatively larger, bodily fluids absorbed into the absorbent core 11a can be made less likely to come into contact with the wearer's skin through the topsheet 12, making rewetting less likely to occur.

[0094] In a preferred embodiment of the present invention, the crepe paper in the skin side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2 has a concave surface on the opposite side of the protrusions. In other words, as shown in FIG. 3(b), the crepe paper has a convex portion 51 that is not solid, and has a concave recess 52 on the opposite side. The recess 52 on the opposite side of the protrusion 51 contains a portion of the pulp fibers of the absorbent core 11a. In other words, the recess 52 is filled with pulp fibers.

[0095] As described above, in the disposable diaper 1, the crepe paper in the skin side core wrap sheet 11b1 includes a portion of the pulp fibers of the absorbent core 11a in the recessed portion 52 on the surface opposite to the protruding portion 51. This increases the contact area between the skin side core wrap sheet 11b1 and the absorbent core 11a. This allows bodily fluids discharged into the disposable diaper 1 during use to be quickly transferred from the skin side core wrap sheet 11b1 to the absorbent core 11a.

[0096] Furthermore, the crepe paper in the non-skin side core wrap sheet 11b2 includes a portion of the pulp fibers of the absorbent core 11a in the recessed portion 52 on the surface opposite to the protruding portion 51. This makes it easier for bodily fluid that has not been absorbed by the absorbent core 11a and has passed through to be diffused in the planar direction, and can be absorbed by the absorbent core 11a on the end side in the longitudinal direction L and / or width direction W.

[0097] Furthermore, since the recessed portions 52 of the skin side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2 contain pulp fibers, it is possible to prevent the skin side core wrap sheet 11b1 and the non-skin side core wrap sheet 11b2 from deforming too much, which would result in a reduction in absorption performance (e.g., absorption speed, absorption amount, etc.).

[0098] As a preferred aspect of this embodiment, the disposable diaper 1 further comprises a plurality of non-skin-side elastic members 17 (and / or 18) extending along the longitudinal direction L at a position overlapping with the absorbent body 11 in the thickness direction T and on the non-skin side of the absorbent body 11 in the thickness direction T.

[0099] As described above, the disposable diaper 1 includes the non-skin side elastic member 17 (and / or 18), which makes it easier to press the skin side portion of the absorbent body 11 against the body. This allows bodily fluids released into the disposable diaper 1 during use to be transferred more quickly from the topsheet 12 to the absorbent body. Furthermore, the non-skin side core wrap sheet 11b2 can be reinforced by the non-skin side elastic member 17 (and / or 18), which further prevents the non-skin side core wrap sheet 11b2 from breaking.

[0100] In a preferred aspect of this embodiment, the disposable diaper 1 further comprises a pair of leakage preventing walls 15 located on both sides of the topsheet 12 in the width direction W and extending along the longitudinal direction L. Each of the pair of leakage preventing walls 15 includes a leakage preventing elastic member 16 extending along the longitudinal direction L. The contractile force per unit length of the leakage preventing elastic member 16 is smaller than the contractile force per unit length of the non-skin-side elastic member 17 (and / or 18).

[0101] As described above, the disposable diaper 1 is provided with a pair of leakage preventing walls 15 having the leakage preventing elastic members 16, thereby preventing side leakage of body fluids in the width direction W. In addition, the non-skin side elastic members 17 (and / or 18) having a greater contractile force per unit length than the leakage preventing elastic members 16 are provided on the non-skin side, thereby making it easier to press the skin side portion of the absorbent body 11 against the body. This allows the body fluids discharged into the disposable diaper 1 to be transferred more quickly from the topsheet 12 to the absorbent body 11 during use, while preventing side leakage of the body fluids.

[0102] 1, the disposable diaper 1 may have a pair of embossed portions E formed in the shape of grooves extending from the surface of the topsheet 12 toward the absorbent body 11 in the thickness direction T and extending along the longitudinal direction L. The degree of unevenness of the skin-side core wrap sheet 11b1 in the region between the pair of embossed portions E is smaller than the degree of unevenness of the skin-side core wrap sheet 11b1 in the regions located outside each of the pair of embossed portions E in the width direction W.

[0103] As described above, in the disposable diaper 1, the degree of unevenness of the skin-side core wrap sheet 11b1 in the region (inner region) between the pair of embossed portions E is relatively small. Therefore, the liquid diffusibility in the planar direction of the skin-side core wrap sheet 11b1 in the inner region can be relatively increased. As a result, in the skin-side core wrap sheet 11b1, during use, body fluid discharged to the inner region can be diffused more quickly in the planar direction (outside the inner region) and then transferred to the absorbent core 11a. Therefore, body fluid can be absorbed in a very wide region in the absorbent body 11, and thus rewetting of the disposable diaper 1 can be made difficult to occur. The inner region can be said to be a region including a central region TA having a width between the pair of embossed portions E in the width direction W and extending in the longitudinal direction L within the range of the absorbent core 11a.

[0104] Furthermore, the degree of unevenness of the skin-side core wrap sheet 11b1 is relatively large in the region (outer region) located on the outer side of each of the pair of embossed portions E in the width direction. Therefore, the liquid diffusibility in the planar direction of the skin-side core wrap sheet 11b1 in the outer region can be relatively small. As a result, during use, the diffusion of bodily fluids that have diffused from the inner region toward the outside (over the embossed portions) can be suppressed in the outer region, while the bodily fluids can be transferred to the absorbent core 11a. Therefore, during use, leakage of bodily fluids to the outside of the disposable diaper 1 can be suppressed in the outer region. The outer region can be said to be the region of the absorbent core 11a excluding the central region TA.

[0105] Next, a method for producing an absorbent article according to an embodiment will be described. Fig. 5 is a schematic diagram showing an example of a method for producing an absorbent article according to an embodiment.

[0106] The absorbent article manufactured by this manufacturing method, i.e., the disposable diaper 1, has the configuration as described above. That is, the disposable diaper 1 includes a top sheet 12, a back sheet 13, and an absorbent body 11 located between the top sheet 12 and the back sheet 13. The absorbent body 11 includes an absorbent core 11a containing pulp fibers, a skin-side core wrap sheet 11b1 located on the skin side of the absorbent core 11a in the thickness direction T, and a non-skin-side core wrap sheet 11b2 located on the non-skin side of the absorbent core 11a in the thickness direction T.

[0107] This manufacturing method includes a preparation step S1 and a formation step S2, and the formation step S2 includes a coating step S21.

[0108] The preparation process S1 includes preparing a continuous top sheet 112 which is a continuous top sheet 12, a continuous skin side core wrap sheet 111b1 which is a continuous skin side core wrap sheet 11b1 formed from crepe paper having unevenness, a continuous non-skin side core wrap sheet 111b2 which is a continuous non-skin side core wrap sheet 11b2 formed from crepe paper having unevenness, a plurality of absorbent cores 11a, and a continuous back sheet 113 which is a continuous back sheet 13.

[0109] In this embodiment, a continuous exterior sheet 114 having a continuous leakproof wall 115 is prepared, which is a continuous exterior sheet 14 (including a leakproof elastic member 16 and non-skin side elastic members 17, 18) further having a leakproof wall 15. Then, a continuous backside sheet 113 is laminated at the center in the width direction W on the skin side of the continuous exterior sheet 114 having the continuous leakproof wall 115, to prepare a continuous laminate 120 composed of the continuous backside sheet 113, the continuous exterior sheet 114 and the continuous leakproof wall 115.

[0110] However, in this embodiment, the skin side core wrap sheet 11b1 (divided into two in the width direction W) and the non-skin side core wrap sheet 11b2 are formed as a single piece, so that the continuous skin side core wrap sheet 111b1 (divided into two in the CD direction) and the continuous non-skin side core wrap sheet 111b2 are a single continuous core wrap sheet 111b.

[0111] The formation process S2 forms a laminate in which a surface sheet 12 portion of the continuous surface sheet 112, a skin side core wrap sheet 11b1 portion of the continuous skin side core wrap sheet 111b1, an absorbent core 11a, a non-skin side core wrap sheet 11b2 portion of the continuous non-skin side core wrap sheet 111b2, and a back sheet 13 portion of the continuous back sheet 113 are laminated in this order.

[0112] First, as shown in FIG. 5(a), the absorbent core 11a is placed on the portion (the center in the CD direction) of the continuous non-skin-side core wrap sheet 111b2 of the continuous core wrap sheet 111b.

[0113] 5(b), the continuous skin-side core wrap sheets 111b1 located on both sides of the absorbent core 11a in the CD direction of the continuous core wrap sheet 111b are folded and joined onto the absorbent core 11a. Then, the front and rear sides of the continuous core wrap sheet 111b in the MD direction of the absorbent core 11a are cut to the size of one absorbent body 11. This forms an absorbent body 11 in which the skin-side core wrap sheet 11b1, absorbent core 11a, and non-skin-side core wrap sheet 11b2 are laminated in this order.

[0114] Next, as shown in FIG. 5(c), the topsheet 12 portion of the continuous topsheet 112 and the absorbent body 11 are arranged so as to face each other.

[0115] 5(d), the top sheet 12 portion of the continuous top sheet 112 is joined to the absorbent body 11. At the same time, the back sheet 13 portion of the continuous back sheet 113 is arranged to face the absorbent body 11. However, in this embodiment, the back sheet 13 portion of the continuous laminate 120 composed of the continuous back sheet 113, the continuous exterior sheet 114, and the continuous leak-proof wall 115 is arranged to face the absorbent body 11.

[0116] 5(e), the topsheet 12 portion of the continuous topsheet 112 and the absorbent body 11 are joined to the backsheet 13 portion of the continuous laminate 120. Then, the front and rear sides of the absorbent core 11a in the MD direction of the continuous topsheet 112 and the continuous laminate 120 are cut to the size of one piece of the topsheet 12 and backsheet 13 (and the exterior sheet 14 and the leakproof wall 15). This forms the absorbent main body 10 in which the topsheet 12, absorbent body 11 and backsheet 13 (and the exterior sheet 14 and the leakproof wall 15) are laminated in this order.

[0117] Here, the joining of the top sheet 12 portion of the continuous top sheet 112 to the absorbent body 11 (step in Figure 5(c)) and the joining of the absorbent body 11 to the back sheet 13 portion of the continuous laminate 120 (step in Figure 5(d)) may be performed simultaneously.

[0118] However, the forming step S2 includes a coating step S21. In the coating step S21, after the continuous skin-side core wrap sheet 111b1 is folded in FIG. 5(b), a composition containing a hydrophilic solvent is coated on the continuous skin-side core wrap sheet 111b1 or the skin-side core wrap sheet 11b1 of the absorbent 11 (schematically indicated by P1). In this case, the composition is coated on the skin-side surface of the skin-side core wrap sheet 11b1. Examples of the coating method include a non-contact coating method (e.g., spraying the composition onto the skin-side core wrap sheet 11b1 with a spray device) and a contact coating method (e.g., discharging the composition onto the skin-side core wrap sheet 11b1 from a nozzle). The coating position is a portion with a relatively small degree of unevenness, as described in the embodiment of the disposable diaper 1.

[0119] The application step S21 may be a step of applying a composition containing a hydrophilic solvent to the top sheet 12 portion of the continuous top sheet 112 in FIG. 5(c) (schematically shown as P2). In this case, the composition is applied to the skin side or non-skin side surface of the top sheet 12 portion. The application method is as described above. After application, when the continuous top sheet 112 is joined to the absorbent body 11, the composition migrates from the top sheet 12 portion to the skin side core wrap sheet 11b1. The migration can be roughly controlled by adjusting the viscosity of the composition. The application position is a portion of the skin side core wrap sheet 11b1 where the degree of unevenness is relatively small, as described in the embodiment of the disposable diaper 1.

[0120] The application step S21 may be a step of applying a composition containing a hydrophilic solvent to the top sheet 12 portion of the continuous top sheet 112 in FIG. 5(d) (schematically shown as P3). In this case, the composition is applied to the skin-side surface of the top sheet 12 portion. The application method is as described above. After application, the composition migrates from the top sheet 12 portion to the skin-side core wrap sheet 11b1. The migration can be roughly controlled by adjusting the viscosity of the composition. The application position is a portion of the skin-side core wrap sheet 11b1 where the degree of unevenness is relatively small, as described in the embodiment of the disposable diaper 1.

[0121] The coating step S21 may be carried out in any one of the above three aspects, but may also be carried out in a combination of two or more aspects.

[0122] Here, the unevenness of the skin side core wrap sheet 11b1 portion of the continuous skin side core wrap sheet 111b1 after the forming step S2 is smaller than the unevenness of the non-skin side core wrap sheet 11b2 portion of the continuous non-skin side core wrap sheet 111b2. This is because in the application step S21, a composition containing a solvent is applied or transferred to the skin side core wrap sheet 11b1 portion of the continuous skin side core wrap sheet 111b1, so that the applied portion becomes soaked in the liquid and softens, and the unevenness is flattened, thereby reducing the unevenness.

[0123] Thereafter, the abdominal side section 2 is joined to one end in the longitudinal direction L of the absorbent body 10, and the dorsal side section 3 is joined to the other end, thereby completing the disposable diaper 1.

[0124] In this manufacturing method, the unevenness of the skin-side core wrap sheet 11b1 can be relatively reduced by the composition applied to the top sheet 12 and transferred to the skin-side core wrap sheet 11b1 in contact with the top sheet 12, or by the composition applied to the skin-side core wrap sheet 11b1. This allows the contact area between the top sheet 12 and the skin-side core wrap sheet 11b1 to be increased. This increases the stability of the bond between the top sheet 12 and the skin-side core wrap sheet 11b1. At the same time, since the unevenness of the skin-side core wrap sheet 11b1 of the manufactured disposable diaper 1 is relatively small, bodily fluids (including sweat) discharged into the disposable diaper 1 during use and transferred from the top sheet 12 to the skin-side core wrap sheet 11b1 can be diffused in the planar direction of the skin-side core wrap sheet 11b1 and then transferred to the absorbent core 11a. Therefore, bodily fluids can be absorbed in a very wide area within the absorbent body 11, thereby reducing the amount of bodily fluids absorbed per unit area in a plan view of the absorbent body 11. This makes it difficult for rewetting to occur after absorbing bodily fluids in the disposable diaper 1. Furthermore, by relatively increasing the degree of unevenness of the non-skin side core wrap sheet 11b2 of the crepe paper, the non-skin side core wrap sheet 11b2 can be made to deform easily, thereby preventing breakage of the non-skin side core wrap sheet 11b2 and the skin side core wrap sheet 11b1 during use.

[0125] The method for making the unevenness of the skin side core wrap sheet 11b1 smaller than that of the non-skin side core wrap sheet 11b2 is not limited to the above method. For example, in the preparation step S1, crepe paper with a small unevenness may be used for the skin side core wrap sheet 11b1 (continuous skin side core wrap sheet 111b1), and crepe paper with a large unevenness may be used for the non-skin side core wrap sheet 11b2 (continuous non-skin side core wrap sheet 111b2).

[0126] In this embodiment, as a preferred aspect, in the application step S21, the composition is applied to at least one of only the central portion in the longitudinal direction L and width direction W of the top sheet 12 portion of the continuous top sheet 112, and only the central portion in the longitudinal direction L and width direction W of the skin side core wrap sheet 11b1 portion of the continuous skin side core wrap sheet 111b1.

[0127] In the manufacturing method, the composition is applied to the center of the top sheet 12 or the skin side core wrap sheet 11b1 in the longitudinal direction L and width direction W, i.e., generally in the excretion opening contact area. This makes it possible to relatively reduce the degree of unevenness in the skin side core wrap sheet 11b1 in the excretion opening contact area. This makes it possible to increase the contact area between the top sheet 12 and the skin side core wrap sheet 11b1 in the excretion opening contact area. This makes it possible to further increase the stability of the bond between the top sheet 12 and the skin side core wrap sheet 11b1.

[0128] Furthermore, the composition is not applied to the ends of the topsheet 12 or the skin-side core wrap sheet 11b1 other than the center in the longitudinal direction L and width direction W. In this way, by not applying the composition to the ends in the longitudinal direction L and width direction W where the adhesive is mainly disposed when the sheets are joined together, the adhesive can function properly at the ends. This makes it possible to prevent the adhesive from not functioning properly during transport in the manufacturing process, thereby preventing problems such as the sheets at the ends of the disposable paper diaper turning over.

[0129] In this embodiment, as a preferred aspect, in the application step S21, the composition is applied, in a planar view, to at least one of the area in the continuous top sheet 112 where the absorbent core 11a is located and the area in the continuous skin side core wrap sheet 111b1 where the absorbent core 11a is located.

[0130] In this manufacturing method, the composition is applied only to the area of ​​the top sheet 12 or the skin side core wrap sheet 11b1 where the absorbent core 11a is arranged in a plan view. By limiting the area to which the composition is applied in this way, even if the skin side core wrap sheet 11b1 is joined to the non-skin side core wrap sheet 11b2 outside the area where the absorbent core 11a is arranged, the composition can be prevented from diffusing from the skin side core wrap sheet 11b1 to the non-skin side core wrap sheet 11b2. This can prevent the unevenness of the non-skin side core wrap sheet 11b2 from decreasing and the adhesive from becoming difficult to function when the sheets are joined together.

[0131] In this embodiment, as a preferred aspect, the composition further comprises a hydrophilic antibacterial agent, the solvent comprises water and an organic solvent, and the amount of water in the solvent is less than the amount of the organic solvent.

[0132] In this manufacturing method, the composition further contains a hydrophilic antibacterial agent, the solvent contains water and an organic solvent, and the amount of water is less than the amount of the organic solvent. In this way, by reducing the ratio of water in the composition, it is possible to suppress the occurrence of rust in the manufacturing equipment. On the other hand, by increasing the ratio of the organic solvent in the composition, it is possible to suppress the antibacterial agent itself from being exposed on the surface of the top sheet and irritating the skin of the wearer.

[0133] <Method for measuring the degree of unevenness of core wrap sheet> The degree of unevenness of the core wrap sheet is measured as follows. (1) The absorbent article is divided into three equal parts in the width direction and length direction to prepare nine samples. (2) After freezing each sample using liquid nitrogen, cut it in the thickness direction with a sharp cutter knife so that the parts where you want to measure the degree of unevenness (e.g., the center part in the longitudinal direction and the width direction, and the part in the longitudinal direction in the front-back direction) can be seen in cross section, without deforming the degree of unevenness. The size of the cut may be 1 cm x 1 cm. (3) Prepare a microscope or optical microscope (e.g., VHX-7000 manufactured by Keyence Corporation) and take images of the cross section of each sample at a magnification of 10 to 100 times. (4) In the photographed image of each sample, the number of irregularities (wrinkles) per unit length and / or the height H and / or width D of the irregularities are measured for each of the concave and convex portions. (5) Calculate the average of the measurements for nine samples (or at least three nearby samples if the difference in location is large (±30% or more)) and use this as the final number of irregularities (wrinkles) per unit length and / or the irregularity height H and / or irregularity width D.

[0134] <Measuring method for the area where antibacterial liquid (containing antibacterial agent) has been applied> The amount of antibacterial liquid (containing an antibacterial agent) in the area where the antibacterial liquid is applied is measured as follows. (1) To check whether or not an antibacterial liquid has been applied, cut out a portion of the absorbent article of a specified size (e.g., 1 cm x 1 cm) and use it as a sample. (2) The antibacterial agents in the samples will be identified and quantified using LC / MS (high performance liquid chromatography mass spectrometry). (3) The above steps (1) and (2) are carried out for three samples, and the average value is calculated to determine the presence or absence and amount of antibacterial solution in that area. (4) The above steps (1) to (3) are carried out on a plurality of portions of the absorbent article, and the areas to which the antibacterial solution has been applied and the amount of the antibacterial solution in those areas are determined. EXAMPLES

[0135] The present invention will be described below based on examples, but the present invention is not limited to these examples.

[0136] (1) Sample (a) Example 1 Surface sheet (air-through nonwoven fabric): basis weight 30g / m 2 , Skin side core wrap sheet (crepe paper tissue): basis weight 15g / m 2 , Absorbent core (pulp fiber): basis weight 60g / m 2, Non-skin side core wrap sheet (crepe paper tissue): basis weight 15g / m 2 , Back sheet (breathable film): basis weight 35g / m 2 A simulated absorbent body was created. However, a simulated composition (1,3-butylene glycol (BG)) was applied to almost the entire surface of the skin-side core wrap sheet using a spray device. It was confirmed that the unevenness of the crepe in this sample had almost disappeared by visual inspection due to the hydrophilic solvent before lamination. Furthermore, the unevenness height was measured with a microscope and was 0.015 mm. (b) Comparative example 1 A simulated absorbent body was prepared with the same structure as in Example 1. However, the simulated composition (1,3-butylene glycol (BG)) was not applied to the skin-side core wrap sheet. In this sample, since there was no hydrophilic solvent before lamination, it was possible to visually confirm the presence of crepe irregularities. Furthermore, when measured with a microscope, the irregularity height was 0.025 mm.

[0137] (2) Evaluation method For the samples of Example 1 and Comparative Example 1, 0.5 ml of artificial blood was dropped from a height of 5 mm above the topsheet, and the degree of diffusion of the artificial blood on the topsheet and the skin-side core wrap sheet after 3 minutes was measured. As the degree of diffusion, the spread width of the artificial blood was measured in the MD and CD directions at the time of manufacturing each sheet. The artificial blood was prepared by mixing 80 g of glycerin, 8 g of sodium salt of CMC, 10 g of NaCl, 4 g of NaHCO3, 8 g of red dye No. 102, 2 g of red dye No. 2, and 2 g of yellow dye No. 5 with 1000 cc of water, and adjusted so that the viscosity was within the range of approximately 22 to 26 mPa·s.

[0138] (3) Evaluation results (a) Example 1 In the top sheet, the artificial blood spread 17 mm in the MD and 18 mm in the CD, while in the skin-side core wrap sheet, the artificial blood spread 31 mm in the MD and 35 mm in the CD. (b) Comparative example 1 In the top sheet, the artificial blood spread 23 mm in the MD and 20 mm in the CD, while in the skin-side core wrap sheet, the artificial blood spread 28 mm in the MD and 23 mm in the CD. (c) Summary Comparing Example 1 and Comparative Example 1, it was found that in the case where the composition was applied to the skin side core wrap sheet and the degree of unevenness was reduced (Example 1), the artificial blood moved from the surface sheet to the skin side core wrap sheet more quickly and diffused in the planar direction within the skin side core wrap sheet more quickly than in the case where the composition was not applied (Comparative Example 1).

[0139] The disposable diaper and its manufacturing method of the present invention are not limited to the above-mentioned embodiments, and it is possible to combine the embodiments or apply publicly known technologies within the scope that does not deviate from the purpose and intent of the present invention. [Explanation of symbols]

[0140] 1. Absorbent articles 11 Absorbent 11a Absorbent Core 11b1 Skin side core wrap sheet 11b2 Non-skin side core wrap sheet

Claims

1. An absorbent article having a longitudinal direction, a width direction and a thickness direction which are perpendicular to each other, the article comprising a top sheet, a back sheet, and an absorbent body located between the top sheet and the back sheet, The absorbent body is an absorbent core comprising pulp fibers; A skin-side core wrap sheet located on the skin side of the absorbent core in the thickness direction; A non-skin side core wrap sheet located on the non-skin side of the absorbent core in the thickness direction; Including, The skin side core wrap sheet and the non-skin side core wrap sheet are made of crepe paper having irregularities, The unevenness of the skin side core wrap sheet is smaller than the unevenness of the non-skin side core wrap sheet. Absorbent articles.

2. The skin side core wrap sheet is Fibers constituting the skin side core wrap sheet; a composition carried by the fibers, the composition comprising a hydrophilic solvent; Including, The absorbent article of claim 1.

3. The composition further comprises a hydrophilic antimicrobial agent. The absorbent article of claim 2.

4. The solvent includes a non-volatile organic material. The absorbent article of claim 3.

5. In the skin side core wrap sheet, the degree of unevenness in the center portion in the longitudinal direction and the center portion in the width direction is smaller than the degree of unevenness in both ends in the longitudinal direction and both ends in the width direction.

3. The absorbent article according to claim 1 or 2.

6. The unevenness of the skin side core wrap sheet is smaller than the unevenness of the skin side of the top sheet.

3. The absorbent article according to claim 1 or 2.

7. The crepe paper in the skin side core wrap sheet and the non-skin side core wrap sheet has a concave surface on the opposite side of the convex portion of the unevenness, the concave portion encompasses a portion of the pulp fibers of the absorbent core; 3. The absorbent article according to claim 1 or 2.

8. a non-skin-side elastic member extending along the longitudinal direction at a position overlapping the absorbent body in the thickness direction and on the non-skin side of the absorbent body in the thickness direction, 3. The absorbent article according to claim 1 or 2.

9. The sheet further includes a pair of leak-proof walls located on both sides in the width direction of the top sheet and extending along the longitudinal direction, Each of the pair of leak-proof walls includes a leak-proof elastic member extending along the longitudinal direction, a contractile force per unit length of the leakage preventing elastic member is smaller than a contractile force per unit length of the non-skin side elastic member; The absorbent article of claim 8.

10. A pair of embossed portions are formed in a groove shape from the surface of the topsheet toward the absorbent body and extend along the longitudinal direction, The unevenness of the skin side core wrap sheet in the region between the pair of embossed portions is smaller than the unevenness of the skin side core wrap sheet in the region located outside each of the pair of embossed portions in the width direction.

3. The absorbent article according to claim 1 or 2.

11. A method for manufacturing an absorbent article having a longitudinal direction, a width direction and a thickness direction perpendicular to each other, the absorbent article comprising a top sheet, a back sheet and an absorbent body located between the top sheet and the back sheet, the absorbent body including an absorbent core containing pulp fibers, a skin-side core wrap sheet located on the skin side of the absorbent core in the thickness direction, and a non-skin-side core wrap sheet located on the non-skin side of the absorbent core in the thickness direction, the method comprising: a preparation step of preparing a continuous top sheet, a continuous skin side core wrap sheet, a continuous skin side core wrap sheet, a continuous non-skin side core wrap sheet, a continuous non-skin side core wrap sheet, a plurality of the absorbent cores, and a continuous back sheet, a continuous back sheet, a continuous back sheet, and a forming step of forming a laminate in which a top sheet portion of the continuous top sheet, a skin side core wrap sheet portion of the continuous skin side core wrap sheet, the absorbent core, a non-skin side core wrap sheet portion of the continuous non-skin side core wrap sheet, and a back sheet portion of the continuous back sheet are laminated in this order; Equipped with The forming step includes a coating step of coating at least one of the top sheet portion of the continuous top sheet and the skin side core wrap sheet portion of the continuous skin side core wrap sheet with a composition containing a hydrophilic solvent; the unevenness of the skin side core wrap sheet portion of the continuous skin side core wrap sheet after the forming step is smaller than the unevenness of the non-skin side core wrap sheet portion of the continuous non-skin side core wrap sheet; method.

12. In the coating step, the composition is coated only on a central portion of the continuous top sheet in the longitudinal direction and the width direction of the top sheet portion, and only on a central portion of the continuous skin side core wrap sheet in the longitudinal direction and the width direction of the skin side core wrap sheet portion. The method of claim 11.

13. In the application step, the composition is applied, in a plan view, only to an area of ​​the continuous top sheet where the absorbent core is disposed, and only to an area of ​​the continuous skin side core wrap sheet where the absorbent core is disposed.

13. The method according to claim 11 or 12.

14. The composition further comprises a hydrophilic antimicrobial agent; The solvent includes water and an organic solvent, In the solvent, the amount of the water is less than the amount of the organic solvent.

13. The method according to claim 11 or 12.

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