Nonwoven fabric sheet for absorbent article and absorbent article

Abstract

Provided is a nonwoven fabric sheet for absorbent article having improved air permeability. This nonwoven fabric sheet for absorbent article has a simple structure, and can be easily applied to various constituent members. The nonwoven fabric sheet (100) for absorbent article is used for an absorbent article. The nonwoven fabric sheet for absorbent articles has: a first region (R1), which is a square with sides of 50 mm in each of a vertical direction (X) and a horizontal direction (Y) orthogonal to each other; and a plurality of second regions (R2) obtained by dividing the first region (R1) into regions with sides of 10 mm in each of the vertical direction and the horizontal direction. When a center region (RC) positioned at the center in the vertical direction and the horizontal direction is defined, the plurality of second regions include a high basis weight region (RH) having a basis weight twice or more the basis weight of fibers in the center region.

Description

Nonwoven Sheet for Absorbent Articles and Absorbent Articles

[0001] Conventionally, there has been a demand for improving the air permeability of nonwoven sheets constituting absorbent articles. For example, Patent Documents 1 and 2 disclose technologies for improving the air permeability of nonwoven sheets. Specifically, the sheets in the patent documents are formed by overlapping a stretchable moisture-permeable film having micropores and a non-stretchable nonwoven fabric, and joining them to each other at a plurality of joining portions scattered between the overlapping surfaces. The moisture-permeable film is stretchable, and with the stretching of the moisture-permeable film, the non-joined portions of the nonwoven fabric with the moisture-permeable film are configured to stretch. Further, the sheet of Patent Document 2 is manufactured by a method having a step of forming a laminate by bringing an elastic filament in a fusible state into contact with a nonwoven fabric and fusing the elastic filament to the nonwoven fabric, and a step of stretching the laminate to perform an elastic expression treatment. As the nonwoven fabric, one having a maximum strength of 40 N / 50 mm or less under the condition of a strain rate of 3.3 s-1 is used, and in the elastic expression treatment step, the laminate is configured to be stretched at a strain rate of 30 s-1 or more and 200 s-1 or less.

[0002] JP-A-2023-153503, JP-A-2023-68337

[0003] Various sheets configured to improve air permeability, such as those in Patent Documents 1 and 2, have been provided. However, in absorbent articles, due to the nature of the articles to absorb body fluids, there is a need to improve the air permeability throughout the absorbent articles, and there is a demand for a sheet that can more easily improve air permeability and is more applicable to various constituent members.

[0004] The present invention has been made in view of such problems, and aims to improve the air permeability of a nonwoven sheet for absorbent articles that has a simple configuration and can be easily applied to various constituent members.

[0005] An absorbent nonwoven sheet according to one embodiment is a sheet used in the absorbent article. The absorbent nonwoven sheet is divided into a first region which is a 50 mm square in each of the mutually orthogonal longitudinal and transverse directions, into a plurality of second regions which are each 10 mm in each of the longitudinal and transverse directions, and a central region located at the center of the longitudinal and transverse directions is defined, wherein the plurality of second regions include high basis weight regions which have a basis weight of twice or more than the basis weight of the fibers in the central region.

[0006] An absorbent article according to one embodiment comprises a nonwoven fabric sheet for absorbent articles and an absorbent core that absorbs bodily fluids.

[0007] Figure 1 is a front view of the absorbent article according to the embodiment. Figure 2 is a plan view of the absorbent article in its unfolded state according to the embodiment. Figure 3 is a cross-sectional view along line A-A shown in Figure 2. Figure 4 is a diagram illustrating each region of the nonwoven fabric sheet. Figure 5 is a diagram showing the basis weight of the second region of the nonwoven fabric sheet. Figure 6 is a diagram showing the measurement area for the basis weight of the second region of the nonwoven fabric sheet. Figure 7 is a diagram showing the measurement data for the measurement area shown in Figure 6.

[0008] (1) Outline of Embodiments The following matters will become clear from the description in this specification and the attached drawings. The invention according to Embodiment 1 is a nonwoven fabric sheet for absorbent articles used in absorbent articles. The nonwoven fabric sheet for absorbent articles is divided into a plurality of second regions of 10 mm each in the longitudinal and transverse directions, and a central region located in the center of the longitudinal and transverse directions is defined, and the plurality of second regions include a high basis weight region having a basis weight of twice or more than the basis weight of the fibers in the central region. According to the nonwoven fabric sheet according to this embodiment, the basis weight of the central region is half or less of the basis weight of the high basis weight region, and the breathability of the sheet can be improved by the central region with a relatively low basis weight. In addition, the high basis weight region is located within the first region centered on the central region. The basis weight of the high basis weight region is twice or more than the basis weight of the central region. Because a high-basis-weight area with more than twice the basis weight is placed within a 50 x 50 mm area, the strength of the central area can be reinforced by the high-basis-weight area, ensuring the overall material strength of the first area.

[0009] In a preferred embodiment, the invention according to Embodiment 2 may have the following features in the invention according to Embodiment 1: The plurality of second regions include a plurality of high basis weight regions. According to this embodiment, the central region can be reinforced by the plurality of high basis weight regions, making it easier to ensure the material strength of the entire first region.

[0010] In a preferred embodiment, the invention according to embodiment 3 may have the following features in the invention according to embodiment 1 or embodiment 2. The plurality of second regions each have a vertical extension region extending from the central region in the vertical direction and a horizontal extension region extending from the central region in the horizontal direction. The high basis weight region is provided in at least one of the vertical extension region and the horizontal extension region. According to this embodiment, the central region can be reinforced by the high basis weight region in at least one of the vertical and horizontal directions, making it easier to ensure the material strength of the entire first region.

[0011] In a preferred embodiment, the invention according to embodiment 4 may have the following features in the invention according to embodiment 3: At least one of the average basis weight of the lateral extension region and the average basis weight of the vertical extension region is 1.5 times or more the basis weight of the central region. According to this embodiment, it is easier to obtain the effect of reinforcing the central region with a high basis weight region in at least one of the vertical and horizontal directions, and it is easier to ensure the material strength of the entire first region.

[0012] In a preferred embodiment, the invention according to Embodiment 5 may have the following features in the invention according to any of Embodiments 1 to 4. The nonwoven sheet includes small-diameter fibers with a fiber diameter of 0.5 μm or more and 4.0 μm or less, and large-diameter fibers with a fiber diameter of 7.0 μm or more and 50.0 μm or less. According to this embodiment, because it has both small-diameter and large-diameter fibers, even if there is a difference in basis weight between the central region and the high-basis weight region, the difference in material strength does not tend to increase in proportion to the difference in basis weight, making it easier to ensure the strength of the entire first region. Furthermore, because it has small-diameter fibers, it is possible to suppress fluffing of the sheet compared to a configuration with only large-diameter fibers.

[0013] In a preferred embodiment, the invention according to embodiment 6 may have the following features in the invention according to any of embodiments 1 to 5. The coefficient of variation of the standard deviation of the basis weight of the second region is 0.1 or more and 0.3 or less. According to this embodiment, the coefficient of variation is 0.1 or more, allowing for variations in basis weight, and enabling the provision of regions for ensuring breathability and regions for ensuring strength. Furthermore, since the coefficient of variation is 0.3 or less, and the variations in basis weight are not too high, the overall strength of the material can be ensured without providing areas with locally weak strength.

[0014] In a preferred embodiment, the invention according to embodiment 7 may have the following features in the invention according to any of embodiments 1 to 6. The nonwoven fabric sheet is provided with compressed sections in which the nonwoven fabric sheet is compressed in the thickness direction. The compressed sections are provided in each of the second regions. According to this embodiment, the strength can be improved by the compressed sections, and compared to a configuration in which strength is increased only by increasing the basis weight, the strength of the material can be improved while increasing the overall breathability of the material.

[0015] The invention according to Embodiment 8 is an absorbent article comprising a nonwoven fabric sheet for absorbent articles described in any of Embodiments 1 to 7, and an absorbent core that absorbs bodily fluids. According to this embodiment, since it is equipped with a nonwoven fabric sheet that makes it easy to ensure breathability and material strength, it is possible to improve the wearing comfort of the absorbent article by ensuring breathability, and to improve the durability of the absorbent article by increasing material strength.

[0016] In a preferred embodiment, the invention according to embodiment 9 may have the following features in the invention according to embodiment 8: The absorbent article has an expandable member that expands and contracts in at least one of the longitudinal and transverse directions. The expandable member overlaps the central region and the high basis weight region. According to this embodiment, in the central region with a relatively low basis weight, large wrinkles can be formed by the expandable member. These large wrinkles can further improve breathability. On the other hand, in the high basis weight region with a relatively high basis weight, smaller wrinkles can be formed by the expandable member. By forming smaller wrinkles, bunching of the absorbent article can be suppressed compared to a configuration with large wrinkles. Therefore, it is possible to achieve both the effect of maintaining the shape of the absorbent article and the effect of ensuring breathability.

[0017] In a preferred embodiment, the invention according to embodiment 10 may have the following features in the invention according to embodiment 8 or embodiment 9. The nonwoven fabric sheet comprises a first nonwoven fabric sheet and a second nonwoven fabric sheet that overlaps the first nonwoven fabric sheet in the thickness direction. The high basis weight region of the second nonwoven fabric sheet overlaps the central region of the first nonwoven fabric sheet. According to this embodiment, since the central region of one nonwoven fabric sheet and the high basis weight region of the other nonwoven fabric sheet overlap, it is easier to obtain the effect of reinforcing the strength of the central region with the high basis weight region. Therefore, it is easier to obtain the effect of increasing the strength of the material.

[0018] In a preferred embodiment, the invention according to embodiment 11 may have the following features in the invention according to any one of embodiments 8 to 10: The absorbent article has a joint that joins the nonwoven fabric sheet and a member that abuts the nonwoven fabric sheet in the thickness direction. The joint overlaps each of the second regions. According to this embodiment, the strength of each second region can be improved by the joint, and the material strength can be improved.

[0019] In a preferred embodiment, the invention according to embodiment 12 may have the following features in the invention according to any one of embodiments 8 to 11. The absorbent article has a crotch area positioned between the legs of the wearer, a front waist area located in front of the crotch area, and a rear waist area located behind the crotch area. The absorbent article is a pant-type absorbent article in which the outer part of the front waist area and the outer part of the rear waist area are joined by side joints. The nonwoven fabric sheet is joined at the side joints. The central region of the nonwoven fabric sheet is joined by the side joints. According to this embodiment, the central region of the nonwoven fabric sheet overlaps the side joints, and the bonding strength of the side joints that overlap the central region, which has a relatively low basis weight, can be reduced. Therefore, the side joints can be easily broken when they are to be broken.

[0020] In a preferred embodiment, the invention according to embodiment 13 may have the following features in the invention according to any one of embodiments 8 to 12. The absorbent article comprises an absorbent body having an absorbent core that absorbs bodily fluids, and an outer covering that covers at least the non-skin side of the absorbent body. The nonwoven fabric sheet is disposed on the outer covering. According to this embodiment, the presence of the nonwoven fabric sheet in the outer covering makes it easier to release moisture from the absorbent body to the outside, and makes it easier to obtain an improved breathability effect.

[0021] In a preferred embodiment, the invention according to embodiment 14 may have the following features in the invention according to any one of embodiments 8 to 13. The outer covering has a plurality of waist sheets that cover the waist of the wearer. The waist sheet has a first waist sheet and a second waist sheet positioned on the non-skin side of the first waist sheet. The outer ends of the first waist sheet and the outer ends of the second waist sheet are positioned at the waist opening without being joined to each other. At least one of the first waist sheet and the second waist sheet is made of the nonwoven fabric sheet. According to this embodiment, since the outer ends of the first waist sheet and the outer ends of the second waist sheet are positioned at the waist opening without being joined to each other, airflow is easily generated between the waist sheets, and the breathability near the waist opening can be improved. In addition, since at least one of the first waist sheet and the second waist sheet is a nonwoven fabric sheet, the effect of improving the breathability of the nonwoven fabric sheet is made easier.

[0022] In a preferred embodiment, the invention according to embodiment 15 may have the following features in the invention according to embodiment 14: One of the outer edges of the first waist sheet and the outer edge of the second waist sheet extends outward in the front-rear direction than the other. The central region is located in the extended region. The region extending further than the other waist sheet has fewer layers of sheets. According to this embodiment, since the central region is provided in the extended region, higher breathability can be obtained and the breathability of the waist opening can be improved.

[0023] (2) Embodiments of nonwoven fabric sheet for absorbent articles and absorbent articles Hereinafter, an embodiment of the nonwoven fabric sheet for absorbent articles (hereinafter referred to as the nonwoven fabric sheet) 100 and the absorbent article 10 will be described with reference to the drawings. In the following drawings, identical or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and the ratios of each dimension etc. may differ from those of reality. Therefore, specific dimensions etc. should be determined by referring to the following explanation. In addition, there may be parts where the relationships and ratios of dimensions differ between drawings.

[0024] The absorbent article 10 comprises a nonwoven fabric sheet 100 and an absorbent core 50 that absorbs bodily fluids. Examples of the absorbent article 10 include pant-type diapers, tape-type diapers, sanitary napkins, sanitary shorts, absorbent liners (panty liners), and absorbent pads. The absorbent article 10 of this embodiment is a pant-type disposable diaper in which the outer part of the front waist area and the outer part of the rear waist area are joined by side joints. Figure 1 is a front view of the absorbent article 10 according to the embodiment, and Figure 2 is a plan view of the absorbent article 10 in an unfolded state. The plan view shown in Figure 1 is a view of the absorbent article 10 in an extended state as seen from the skin side T1. In this invention, the extended state is a state in which the absorbent article 10 is extended to a state in which no wrinkles are formed when the side joint 60, which will be described later, is unfolded. Figure 3 is a cross-sectional view along the line A-A shown in Figure 2.

[0025] The absorbent article 10 has a front-to-back direction L, a width direction W, and a thickness direction T, all of which are perpendicular to each other. The front-to-back direction L is defined by the direction extending toward the front and rear of the body. In other words, the front-to-back direction L is the direction extending in the front-to-back direction in the unfolded absorbent article 10. The absorbent article 10 also has a thickness direction T that is perpendicular to both the front-to-back direction L and the width direction W. The thickness direction T extends toward the skin side T1 toward the wearer and toward the non-skin side T2 toward the side away from the wearer.

[0026] The absorbent article 10 has a crotch area S3, a front torso area S1 located in front of the crotch area S3, and a rear torso area S2 located behind the crotch area S3. The front torso area S1 and the rear torso area S2 constitute a torso area that covers the wearer's torso. The front torso area S1 is the area that comes into contact with the wearer's abdominal side. The rear torso area S2 is the area that comes into contact with the wearer's back side. The crotch area S3 is located in the crotch of the wearer and is positioned between the front torso area S1 and the rear torso area S2.

[0027] The absorbent article 10 is provided with a pair of side joints 60 that join the outer part of the front waist area S1 and the outer part of the rear waist area S2. The absorbent article 10 is folded in half using a fold located in the center of the front-to-back direction L as a starting point, and in this folded state, it is joined by the side joints 60 to form a pant shape. The fold extends in the width direction W and is a fold that folds the absorbent article 10 in half so that the skin-side surfaces T1 of the absorbent article 10 face each other. The side joints 60 are defined by the parts that lock the outer part of the front waist area S1 and the outer part of the rear waist area S2 together, and may extend along the front-to-back direction L in each of the front waist area S1 and the rear waist area S2.

[0028] Here, the outer portion in this invention refers to a portion occupying a certain range in the width direction W, including the edge in the width direction W, and the outer edge refers to the edge in the width direction W. Furthermore, the outer end edge in this invention refers to the edge located on the outside in the front-rear direction L, and the inner end edge refers to the edge located on the inside in the front-rear direction L. The absorbent article 10 has a waist opening 62 through which the wearer's torso passes, and a pair of leg openings 66 into which the wearer's legs are inserted. The waist opening 62 is defined by the front end edge of the front waist area S1 and the rear end edge of the rear waist area S2. The boundary between the front waist area S1 and the crotch area S3 may be defined by the rear end edge of the side joint 60 provided in the front waist area S1, and the boundary between the rear waist area S2 and the crotch area S3 may be defined by the front end edge of the side joint 60 provided in the rear waist area S2.

[0029] The absorbent article 10 may have an absorbent body 40 and an outer casing 30. The absorbent body 40 may have an absorbent core 50, a liquid-permeable top sheet 41 covering the skin side T1 of the absorbent core 50, a liquid-impermeable back sheet 42 covering the non-skin side T2 of the absorbent core 50, and a non-skin side sheet 43 covering the non-skin side T2 of the back sheet 42. The absorbent body 40 may be located at least in the crotch area S3 and may extend to the front waist area S1 and the rear waist area S2. The absorbent core 50 is located at least in the crotch area S3 and has an absorbent material. The absorbent material may be pulverized pulp or superabsorbent polymer (SAP), or a mixture thereof. The absorbent core 50 is located at least in the crotch area S3. The top sheet 41 and the non-skin side sheet 43 may be made of nonwoven fabric. The back sheet 42 may be made of film. The top sheet 41 and the non-skin side sheet 43 may constitute the "nonwoven fabric sheet" of the present invention.

[0030] The absorbent body 40 may have leak-proof gathers 45 that can stand upright on the skin side T1. The leak-proof gathers 45 are arranged on both sides of the center of the width direction W of the absorbent body 40 and stand upright on the skin side T1 than the top sheet 41. The leak-proof gathers 45 may be composed of a portion of the outer part of the non-skin side sheet 43 that is folded back on the skin side T1 than the top sheet 41, and a leak-proof stretchable member 46 joined to the folded portion. The leak-proof stretchable member 46 is joined to the non-skin side sheet 43 in a state that allows it to be stretched in the front-rear direction L. The leak-proof stretchable member 46 may constitute the "stretchable member" of the present invention.

[0031] The outer casing 30 is positioned at least on the non-skin side T2 of the absorbent body 40. The outer casing 30 has a plurality of waist sheets. The waist sheets are sheets other than the absorbent body 40 that are positioned in the waist area. The waist sheets may include a first waist sheet 35 and a second waist sheet 36 positioned on the non-skin side T2 of the first waist sheet 35. At least one of the first waist sheet 35 and the second waist sheet 36 may constitute the "nonwoven fabric sheet" of the present invention. In a modified example, the outer end of the second waist sheet 36 may be folded back to the skin side T1 with the waist opening 62 as the base point, and positioned on the skin side T1 of the first waist sheet 35 and the absorbent body 40.

[0032] The front waist area S1 may be provided with a waist stretchable member that expands and contracts in the width direction W. The waist stretchable member may be made of a thread elastic that is expandable in the width direction W, or an elastic sheet that is expandable in the width direction W. The waist stretchable member of this embodiment is made of a thread elastic and has a front waist stretchable member 31 located in the front waist area S1 and a rear waist stretchable member 32 located in the rear waist area S2. The waist stretchable member only needs to be located in the waist area, and may be located across the waist area and the crotch area. The waist stretchable member of this embodiment has a leg stretchable member 38 located across the rear waist area S2 and the crotch area S3, and positioned along the leg opening 66. The leg stretchable member 38 curves from the outer part in the width direction of the rear waist area S2 toward the inside in the width direction W, toward the inside in the front-to-back direction (crotch area side). The front torso expandable member 31, the rear torso expandable member 32, and the leg expandable member 38 may constitute the "expandable member" of the present invention.

[0033] Next, the nonwoven fabric sheet 100 will be described. The nonwoven fabric sheet 100 is a sheet used in one of the components that make up the absorbent article 10. In this embodiment, the first waist sheet 35 and the second waist sheet 36 are made of the nonwoven fabric sheet 100. Figure 4 is a diagram for explaining each region of the nonwoven fabric sheet 100. The nonwoven fabric sheet 100 can define a first region R1 in which each of the mutually orthogonal vertical direction X and horizontal direction Y is a 50 mm square. Figure 4(A) shows the first region R1 which is a 50 mm square. The nonwoven fabric sheet 100 can divide the first region R1 into a plurality of second regions R2 in which each of the vertical direction X and horizontal direction Y is 10 mm, and can define a central region RC located at the center of the vertical direction X and horizontal direction Y in the first region R1 (plural second regions R2). Figure 4(B) shows a plurality of second regions R2 in which each of the vertical direction X and horizontal direction Y is 10 mm. The 25 squares shown in Figure 4(B) all constitute the second region R2, and the square located at the center constitutes the central region RC. The central region RC can be defined by the region with a lower basis weight than the surrounding area when multiple second regions are defined.

[0034] The nonwoven fabric sheet 100 only needs to have dimensions of at least the first region (50 mm x 50 mm), and may be greater than or equal to the dimensions of the first region R1. In this embodiment, the vertical direction X of the nonwoven fabric sheet 100 is the front-to-back direction L, but in modified examples, it may be the width direction W. Furthermore, the vertical direction X of the nonwoven fabric sheet 100 does not need to be parallel to the front-to-back direction L or the width direction W, and may be inclined with respect to the front-to-back direction L or the width direction W.

[0035] Figure 5 shows the basis weight of the second region R2 of the nonwoven fabric sheet 100. Figure 5(A) shows the basis weight of the second region R2 of the nonwoven fabric sheet 100 according to Example 1, which corresponds to the embodiment, and Figure 5(B) shows the basis weight of the second region R2 of the nonwoven fabric sheet 100X according to Comparative Example 1. The unit of basis weight is g / m². ２ In this embodiment, a plurality of second regions R2 include high-basis-weight regions RH having a basis weight of at least twice that of the fiber basis weight of the central region RC. The high-basis-weight regions RH are regions having a basis weight of at least twice that of the central region RC. The basis weight of the central region RC according to this embodiment is 7 g / m². ２ Therefore, the RH in the high basis weight region is 14 g / m². ２ The above is the basis weight range. In Figure 5(A), the high basis weight region RH is hatched. As shown in Figure 5(B), the second region R2 of the modified nonwoven sheet 100X all have a basis weight of less than twice that of the central region RC, and do not have a high basis weight region RH.

[0036] Figure 7 shows measurement data for some of the 25 regions of the second region R2, and Figure 6 shows the measurement locations for the said measurement data. Figures 6 and 7 show the basis weight of some of the second region R2 of the nonwoven fabric sheets according to Examples 2 to 6, and the basis weight of some of the second region R2 of the nonwoven fabric sheets according to Comparative Examples 2 to 6. Some of the regions are the central region RC and the second regions R201 to R212, a total of 13 regions, which are shown in Figure 6. In Figure 7, the basis weight of each second region and whether or not it corresponds to the high basis weight region RH are shown. In Figure 7, regions that correspond to the high basis weight region RH are marked with "○", and regions that do not correspond to the high basis weight region RH are marked with "×".

[0037] The nonwoven fabric sheets according to Examples 1 to 6 all have a high basis weight range RH, while the nonwoven fabric sheets according to Comparative Examples 1 to 6 do not have a high basis weight range RH. The nonwoven fabric sheets according to Examples 1 to 6 all achieved better breathability than the nonwoven fabric sheets according to Comparative Examples 1 to 6. Furthermore, the nonwoven fabric sheets according to Examples 1 to 6 ensured durability equivalent to that of the nonwoven fabric sheets according to Comparative Examples 1 to 6 in the normal use of absorbent articles.

[0038] In the nonwoven fabric sheet 100 of this embodiment, the basis weight of the central region RC is less than half the basis weight of the high-basis-weight region RH, and the breathability of the sheet can be improved by the relatively low basis weight of the central region RC. Furthermore, the high-basis-weight region RH is arranged within the first region R1 centered on the central region RC. The basis weight of the high-basis-weight region RH is more than twice the basis weight of the central region RC. Since the high-basis-weight region RH, which has more than twice the basis weight, is arranged within a 50 x 50 mm area, the strength of the central region RC can be reinforced by the high-basis-weight region RH, and the material strength of the entire first region R1 can be ensured. Note that the nonwoven fabric sheet 100 may include regions that do not satisfy the basis weight relationship, as long as the constituent members (in this embodiment, the first girdle sheet 35 and the second girdle sheet 36) include the first region R1 that satisfies the basis weight relationship.

[0039] The high basis weight region RH only needs to be composed of at least one second region R2 out of the 24 second regions R2 excluding the central region RC. However, preferably, multiple second regions R2 may include multiple high basis weight regions RH. According to this embodiment, the central region RC can be reinforced by multiple high basis weight regions RH, making it easier to ensure the overall material strength of the first region R1. In this embodiment, the second region R2 includes eight high basis weight regions RH.

[0040] The plurality of second regions include a vertically extending region RX that extends vertically from the central region and a horizontally extending region that extends horizontally from the central region RC. The vertically extending region RX is a region located on both sides of the central region RC in the vertical direction, and is composed of four second regions each including two second regions on both sides of the central region RC. The horizontally extending region RY is a region located on both sides of the central region RC in the horizontal direction, and is composed of four second regions each including two second regions on both sides of the central region RC. In FIG. 4(C), different hatchings are applied to the vertically extending region RX and the horizontally extending region RY.

[0041] The high basis weight region RH may be provided in at least one of the vertically extending region RX and the horizontally extending region RY. According to this aspect, in at least one of the vertical direction X and the horizontal direction Y, the central region RC can be reinforced by the high basis weight region RH, and it is easier to ensure the material strength of the entire first region R1. Preferably, the high basis weight region RH may be provided in both the vertically extending region RX and the horizontally extending region RY.

[0042] The average basis weight of the horizontally extending region RY and the average basis weight of the vertically extending region RX may be 1.5 times or more of the basis weight of the central region RC. According to this aspect, in at least one of the vertical direction X and the horizontal direction Y, the central region RC can be reinforced by the high basis weight region RH, and it is easier to ensure the material strength of the entire first region R1. Preferably, both the average basis weight of the horizontally extending region RY and the average basis weight of the vertically extending region RX may be 1.5 times or more of the basis weight of the central region RC. The basis weight of the central region RC in this embodiment is 7 g / m ２ and the average basis weight of the horizontally extending region RY is 11.5 g / m ２ and the average basis weight of the vertically extending region RX is 11.0 g / m ２ Accordingly.

[0043] The nonwoven fabric sheet 100 may contain small-diameter fibers with a fiber diameter of 0.5 μm or more and 4.0 μm or less, and large-diameter fibers with a fiber diameter of 7.0 μm or more and 50.0 μm or less. According to this embodiment, because it has both small-diameter and large-diameter fibers, even if there is a difference in basis weight between the central region RC and the high-basis-weight region RH, the difference in material strength does not tend to increase proportionally to the difference in basis weight, making it easier to ensure the strength of the entire first region. Furthermore, because it contains small-diameter fibers, fluffing of the sheet can be suppressed compared to a composition consisting only of large-diameter fibers. The nonwoven fabric sheet may be a nonwoven fabric containing fibers of different fiber diameters, and an SMS (spunbond + meltblown + spunbond) nonwoven fabric can be suitably used. In the case of an SMS nonwoven fabric, the spunbond fibers may be large-diameter fibers with a fiber diameter of 7.0 μm or more and 50.0 μm or less, and the meltblown fibers may be small-diameter fibers with a fiber diameter of 0.5 μm or more and 4.0 μm or less.

[0044] The coefficient of variation of the standard deviation of the basis weight in the second region R2 may be 0.1 or more and 0.3 or less. According to this embodiment, the coefficient of variation of the standard deviation is 0.1 or more, allowing for variations in basis weight, and enabling the creation of regions that ensure breathability and regions that ensure strength. Furthermore, since the coefficient of variation of the standard deviation is 0.3 or less, and the variations in basis weight are not too high, the overall strength of the material can be ensured without creating areas with locally weak strength. Total number of units in the second region: 25 <Example 1> Total basis weight of the second region in Example 1 = 302 Average basis weight of the second region in Example 1 = 12.08 Population standard deviation of Example 1 = 2.591061559 Coefficient of variation of the standard deviation of Example 1 = 2.591061559 / 12.08 = 0.214491851 <Comparative Example 1> Total basis weight of the second region in Comparative Example 1 = 352 Average basis weight of the second region in Comparative Example 1 = 14.08 Population standard deviation of Comparative Example 1 = 1.957958120 Coefficient of variation of the standard deviation of Comparative Example 1 = 1.957958120 / 14.08 = 0.139059525

[0045] The nonwoven fabric sheet 100 may be provided with a squeezed portion where the nonwoven fabric sheet 100 is compressed in the thickness direction T. The squeezed portion only needs to be formed by compressing the nonwoven fabric sheet 100 in the thickness direction T, and may be constituted by a fused portion where the fibers are fused. Further, the squeezed portion may be formed in the process of molding the nonwoven fabric sheet 100, or may be formed by compressing only the nonwoven fabric sheet or together with other constituent members after molding the nonwoven fabric sheet 100. The squeezed portion may be provided in each of the second regions R2. The squeezed portion only needs to be formed at least one in all the second regions (25 regions), and a plurality of them may be formed in each second region. According to this aspect, the strength can be improved by the squeezed portion, and the air permeability of the entire material can be improved while improving the material strength as compared with a configuration that improves the strength only by increasing the basis weight.

[0046] Next, the absorbent article 10 having the nonwoven fabric sheet 100 configured as described above will be described. Since the absorbent article 10 includes the nonwoven fabric sheet 100 that easily ensures air permeability and material strength, it is possible to ensure air permeability and improve the wearing feeling of the absorbent article 10, and to increase the material strength and improve the durability of the absorbent article 10.

[0047] The nonwoven fabric sheet 100 may be disposed on the outer package 30. Since the outer package 30 has the nonwoven fabric sheet 100, it is easier to let the moisture on the absorbent body 40 side out to the outside, and it is easier to obtain the effect of improving air permeability. Preferably, the nonwoven fabric sheet 100 may be disposed on the surface of the outer package 30 that is the most non-skin side T2. According to this configuration, it is easier to obtain the effect of releasing moisture to the outside of the absorbent article 10.

[0048] In the configuration in which the outer casing 30 has a nonwoven fabric sheet 100, the central region RC may be located in a region that does not overlap with the absorbent body 40. The outer casing 30 in the region that does not overlap with the absorbent body 40 has fewer layers of constituent members, making it easier to improve breathability. By locating the central region RC in this region, it is easier to obtain the effect of improving breathability. Also, in the configuration in which the outer casing 30 has a nonwoven fabric sheet 100, the high basis weight region RH may be located in a region that overlaps with the absorbent body 40. This ensures the rigidity of the material in the region that overlaps with the absorbent body 40, and prevents damage to the material even when the absorbent core 50 becomes heavy when absorbing bodily fluids. Furthermore, the high basis weight region RH may be located near the waist opening 62 (within a range of 30 mm from the waist opening 62). According to this configuration, damage to the material when it is pulled by hand during lifting can be suppressed. Also, damage to the material can be suppressed even when the absorbent core 50 absorbs bodily fluids and its weight becomes heavy.

[0049] The absorbent article 10 of this embodiment has a first waist sheet 35 and a second waist sheet 36, which are nonwoven fabric sheets 100. The first waist sheet 35 and the second waist sheet 36 are arranged on the non-skin side of the front waist area S1 and the non-skin side of the rear waist area S2, respectively. According to this embodiment, the breathability of the front waist area S1 and the rear waist area S2, which surround the wearer's waist, can be improved to reduce stuffiness and improve wearing comfort. The first waist sheet 35 is arranged on the side closest to the skin in the waist area, and is easily grasped by hand and subjected to force during the putting-on process, and is also easily subjected to force when rubbed against the skin during wear. By using a nonwoven fabric sheet 100, which is easy to ensure material strength, as the first waist sheet 35, durability can be improved. Furthermore, the second waist sheet 36 is positioned on the non-skin side of the waist area, making it susceptible to being gripped by hands and subjected to force during the fitting process, or to friction with clothing or bedding during wear. By using a nonwoven fabric sheet 100, which is easy to ensure material strength, as the second waist sheet 36, durability can be improved.

[0050] The stretchable members of the absorbent article 10 may overlap the central region RC and the high basis weight region RH. In this embodiment, the first waist sheet 35 and the second waist sheet 36 overlap the front body stretchable member 31 and the rear body stretchable member 32, respectively. The front body stretchable member 31 and the rear body stretchable member 32 overlap the central region RC and the high basis weight region RH. According to this embodiment, in the central region RC, which has a relatively low basis weight, large wrinkles can be formed by the stretchable members. These large wrinkles can further improve breathability. On the other hand, in the high basis weight region RH, which has a relatively high basis weight, smaller wrinkles can be formed by the stretchable members. By forming smaller wrinkles, bunching of the absorbent article can be suppressed compared to a configuration in which large wrinkles are formed. Therefore, it is possible to achieve both the effect of maintaining the shape of the absorbent article and the effect of ensuring breathability.

[0051] Furthermore, in the configuration where the front body expandable member 31 and the rear body expandable member 32 overlap the central region RC and the high-basis-weight region RH, different expandable members may overlap the central region RC and the high-basis-weight region RH, respectively, or the same expandable member may overlap the central region RC and the high-basis-weight region RH, which are located within the same first region R1. In addition, the expandable member may be continuous over the entire lateral Y or vertical X direction of the first region R1. With this configuration, wrinkles of various sizes can be formed over the entire lateral Y or vertical X direction of the first region R1.

[0052] The absorbent article 10 may have a plurality of nonwoven fabric sheets 100, and the nonwoven fabric sheet 100 may have a first nonwoven fabric sheet and a second nonwoven fabric sheet that overlaps the first nonwoven fabric sheet in the thickness direction. In this embodiment, the high basis weight region RH of the second nonwoven fabric sheet may overlap the central region RC of the first nonwoven fabric sheet. Specifically, the high basis weight region RH of the second nonwoven fabric sheet may overlap the central region RC of the first girth sheet, or the high basis weight region RH of the first nonwoven fabric sheet may overlap the central region RC of the second girth sheet. According to this embodiment, since the central region of one nonwoven fabric sheet and the high basis weight region of the other nonwoven fabric sheet overlap, it is easier to obtain the effect of reinforcing the strength of the central region RC with the high basis weight region RH. Therefore, it is easier to obtain the effect of increasing the strength of the material. In this embodiment, one of the first waist sheet 35 and the second waist sheet 36 constitutes the first nonwoven fabric sheet, and the other constitutes the second nonwoven fabric sheet.

[0053] The absorbent article 10 has a joint that joins a nonwoven fabric sheet 100 and a member that abuts the nonwoven fabric sheet 100 in the thickness direction T. Examples of the member that abuts the nonwoven fabric sheet 100 in the thickness direction include a member that constitutes the absorbent body 40 (for example, a non-skin side sheet 43), an elastic member (for example, a front body elastic member 31 and a rear body elastic member 32), and other nonwoven fabric sheets (for example, a first waist sheet 35 and a second waist sheet). The joint may be a joint made by adhesive or a joint made by compression.

[0054] The joint in this embodiment has a first joint 81 that joins the first waist sheet 35 and the second waist sheet 36, and a second joint 82 that joins the first waist sheet 35 and the non-skin side sheet 43. The first joint 81 joins the first waist sheet 35 and the second waist sheet 36, as well as joining the first waist sheet 35 to the waist stretchable member and the second waist sheet 36 to the waist stretchable member. The joint overlaps each of the second regions R2. That is, the joint overlaps all 25 second regions. According to this embodiment, the strength of each second region R2 can be improved by the joint, and the material strength can be improved. If multiple joints are provided, it is sufficient that any of the joints overlap each second region R2. For example, it is sufficient that some of the 25 second regions R2 overlap the first joint 81, and the other second regions R2 overlap the second joint 82.

[0055] The nonwoven fabric sheet 100 may be joined at the side joint 60. The central region RC of the nonwoven fabric sheet 100 may be joined by the side joint 60. In this embodiment, the side joint 60 joins the first girdle sheet 35 and the second girdle sheet 36, and both sheets constitute the nonwoven fabric sheet 100. Therefore, either the central region RC of the first girdle sheet 35 or the central region RC of the second girdle sheet 36 may overlap the side joint 60. According to this embodiment, the central region RC of the nonwoven fabric sheet 100 overlaps the side joint 60, and the bonding strength of the side joint 60 that overlaps the central region RC, which has a relatively low basis weight, can be reduced. Therefore, the side joint 60 can be easily broken when it is necessary to break it. In addition, the high basis weight region RH may overlap the side joint 60. Since the central region RC and the high-basis-weight region RH each overlap the side joint 60, the strength of the side joint 60 is ensured when worn, and the side joint 60 can be easily peeled off when attaching or detaching.

[0056] The outer ends of the first waist sheet 35 and the outer ends of the second waist sheet 36 may be arranged in the waist opening 62 without being joined to each other. At least one of the first waist sheet 35 and the second waist sheet 36 may be made of a nonwoven fabric sheet 100. In this embodiment, since the outer ends of the first waist sheet 35 and the outer ends of the second waist sheet 36 are arranged in the waist opening 62 without being joined, airflow is easily generated between the waist sheets, improving ventilation near the waist opening 62. In addition, since at least one of the first waist sheet 35 and the second waist sheet 36 is a nonwoven fabric sheet 100, the effect of improved ventilation of the nonwoven fabric sheet 100 is more easily achieved. In this embodiment, the first joining portion 81 is arranged inward in the front-rear direction L from the outer edge of the first waist sheet 35 and the outer edge of the second waist sheet 36, and the outer ends of the first waist sheet 35 and the second waist sheet 36 are not joined.

[0057] One of the outer edges of the first waist sheet 35 and the second waist sheet 36 may extend further outward in the front-rear direction L than the other. The central region RC may be located in the extended region. According to this embodiment, the region extending further than the other waist sheet has fewer layers of sheets. Since the central region is provided in the extended region, higher ventilation can be obtained, and the ventilation of the waist opening can be improved. For example, in the configuration in which the outer edge of the first waist sheet 35 extends further outward in the front-rear direction L than the outer edge of the second waist sheet 36, it is sufficient that the central region RC is located in the extended region of the first waist sheet 35, and in the configuration in which the outer edge of the second waist sheet 36 extends further outward in the front-rear direction than the outer edge of the first waist sheet 35, it is sufficient that the central region RC is located in the extended region of the second waist sheet 36.

[0058] Although the present invention has been described in detail using the embodiments described above, it will be clear to those skilled in the art that the present invention is not limited to the embodiments described herein. The present invention can be implemented in modified and altered forms without departing from the spirit and scope of the invention as defined by the claims. Therefore, the description herein is for illustrative purposes only and is not intended to be restrictive in any way to the present invention.

[0059] For example, the nonwoven fabric sheet 100 in this embodiment constitutes a first waist sheet 35 and a second waist sheet 36, but is not limited to this configuration. The nonwoven fabric sheet 100 may constitute one of the first waist sheet 35 and the second waist sheet 36, or it may constitute other sheets (top sheet 41, non-skin side sheet 43, etc.). Also, the stretchable member in this embodiment constitutes a front waist stretchable member 31 and a rear waist stretchable member 32, but is not limited to this configuration. The stretchable member may constitute one of the front waist stretchable member 31 and the rear waist stretchable member 32, or it may constitute other stretchable members (for example, a leg stretchable member 38, a leak-proof stretchable member 46, etc.).

[0060] This method allows for improved breathability of nonwoven fabric sheets for absorbent articles, with a simple structure that can be easily applied to various components.

[0061] 10: Absorbent article 30: Outer body 31: Front torso stretchable member (stretchable member) 32: Rear torso stretchable member (stretchable member) 35: First torso sheet 36: Second torso sheet 40: Absorbent main body 50: Absorbent core 60: Side joint 62: Torso opening 100: Nonwoven fabric sheet R1: First region R2: Second region RC: Center region RH: High basis weight region RX: Vertical extension region RY: Horizontal extension region S1: Front torso region S2: Rear torso region S3: Crotch region T: Thickness direction T1: Skin side T2: Non-skin side X: Vertical direction Y: Horizontal direction

Claims

1. A nonwoven fabric sheet for absorbent articles used in the absorbent article, wherein a first region, each of which is a 50 mm square in both the longitudinal and transverse directions, is divided into a plurality of second regions, each of which is 10 mm in both the longitudinal and transverse directions, and a central region located at the center of the longitudinal and transverse directions is defined, the plurality of second regions include a high basis weight region having a basis weight of twice or more the basis weight of the fibers in the central region.

2. The nonwoven fabric sheet for absorbent articles according to claim 1, wherein the plurality of second regions include a plurality of high basis weight regions.

3. The plurality of second regions each have a vertical extension region extending vertically from the central region and a horizontal extension region extending horizontally from the central region, and the high basis weight region is provided in at least one of the vertical extension region and the horizontal extension region, as described in claim 1.

4. The nonwoven fabric sheet for absorbent articles according to claim 3, wherein at least one of the average basis weight of the horizontal extension region and the average basis weight of the vertical extension region is 1.5 times or more the basis weight of the central region.

5. The nonwoven fabric sheet for absorbent articles according to claim 1, wherein the nonwoven fabric sheet comprises small-diameter fibers having a fiber diameter of 0.5 μm or more and 4.0 μm or less, and large-diameter fibers having a fiber diameter of 7.0 μm or more and 50.0 μm or less.

6. The coefficient of variation of the standard deviation of the basis weight in the second region is 0.1 or more and 0.3 or less, the nonwoven fabric sheet for absorbent articles according to claim 1.

7. The nonwoven fabric sheet for absorbent articles according to claim 1, wherein the nonwoven fabric sheet is provided with a compression section in the thickness direction, and the compression section is provided in each of the second regions.

8. An absorbent article comprising the nonwoven fabric sheet for absorbent articles described in any one of claims 1 to 7, and an absorbent core for absorbing bodily fluids.

9. The absorbent article according to claim 8, having an expandable member that expands and contracts in at least one of the vertical and horizontal directions, wherein the expandable member overlaps the central region and the high basis weight region.

10. The absorbent article according to claim 8, wherein the nonwoven fabric sheet comprises a first nonwoven fabric sheet and a second nonwoven fabric sheet overlapping the first nonwoven fabric sheet in the thickness direction, and the high basis weight region of the second nonwoven fabric sheet overlaps the central region of the first nonwoven fabric sheet.

11. The absorbent article according to claim 8, having a joint that joins the nonwoven fabric sheet and a member that abuts the nonwoven fabric sheet in the thickness direction, wherein the joint overlaps each of the second regions.

12. The absorbent article is a pant-type absorbent article having a crotch area positioned between the legs of the wearer, a front waist area located in front of the crotch area, and a rear waist area located behind the crotch area, wherein the outer part of the front waist area and the outer part of the rear waist area are joined by side joints, the nonwoven fabric sheet is joined at the side joints, and the central region of the nonwoven fabric sheet is joined by the side joints, as described in claim 8.

13. The absorbent article according to claim 8, comprising an absorbent body having an absorbent core for absorbing bodily fluids, and an outer covering covering at least the non-skin side of the absorbent body, wherein the nonwoven fabric sheet is disposed on the outer covering.

14. The absorbent article according to claim 8, wherein the outer covering has a plurality of waist sheets that cover the waist of the wearer, the waist sheet comprises a first waist sheet and a second waist sheet positioned on the non-skin side of the first waist sheet, the outer end of the first waist sheet and the outer end of the second waist sheet are positioned without being joined to each other at the waist opening, and at least one of the first waist sheet and the second waist sheet is made of the nonwoven fabric sheet.

15. The absorbent article according to claim 14, wherein one of the outer edges of the first waist sheet and the second waist sheet extends outward in the front-rear direction than the other, and the central region is located at least in the extended region.

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