Absorbent article

Abstract

Provided is an absorbent article that inhibits slipping. In front waist regions (S1) and back waist regions (S2) of an absorbent article (1), a plurality of regions are provided that are divided in the length direction (L) of the front waist regions and the back waist regions. The plurality of regions include a front waist region (F11), an upper abdomen region (F12), a lower abdomen region (F13) located at a position that is 50 to 85% of the full length of the length direction of the front waist regions from the front end edge of the front waist regions toward the back, a front leg region (F14), a back waist region (R11) located at a position that is 0 to 25% of the full length of the length direction of the back waist regions from the back end edge of the back waist regions toward the front, an upper back region (R12), a lower back region (R13), and a back leg region (R14). The tensile stress in the width direction of the lower abdomen region is greater than that of any region of the front waist regions. The tensile stress in the width direction of the back waist region is greater than that of any region of the back waist regions.

Description

Technical Field

[0001] This invention relates to absorbent articles such as disposable diapers. Background Technology

[0002] Disposable diapers and other absorbent articles are worn to cover the abdomen and back of the body, configured to prevent slippage (e.g., Patent Document 1 below). The absorbent article in Patent Document 1 is configured such that it is difficult for the absorbent article to shift relative to the wearer's body movements. More specifically, in the lower back area, a first elastic portion and a second elastic portion located below the crotch are provided. The first and second elastic portions are spaced apart in the longitudinal direction. The elastic stress of the first and second elastic portions is greater than the elastic stress of the area between the first and second elastic portions. Therefore, when the absorbent article is worn, the first and second elastic portions fit snugly against the body, while the area between the first and second elastic portions is relatively less snug against the body.

[0003] For example, if the wearer moves their thighs by bending or stretching, the second elastic section in the back waist area, located on the crotch side, is pulled towards the groin. Furthermore, as the second elastic section moves towards the groin, the area between the first and second elastic sections is also pulled towards the groin. The area between the first and second elastic sections experiences less stretching stress and does not conform tightly to the body. Therefore, when a pulling force is applied along the length of the back waist area of ​​the disposable diaper due to the wearer's body movements, the area between the first and second elastic sections acts as a buffer zone, absorbing the skin's stretching changes caused by body movements. This prevents the first elastic section from shifting towards the groin. Additionally, the first and third elastic sections are connected, as are the second and third elastic sections. That is, the elastic sections in the front and back waist areas are arranged to cover the wearer's waist circumference. Therefore, if the second elastic section shifts towards the groin, it can be pulled back to its original position by the third elastic section. Thus, the absorbent article of Patent Document 1 is configured to inhibit displacement.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-202246 Summary of the Invention

[0007] There is a significant need to suppress the shifting of absorbent fabrics, and there is still room for improvement. In particular, if the absorbent fabric does not fit the wearer's body shape, it will shift at the unsuitable location, potentially leading to overall shifting of the absorbent fabric during wear. Therefore, the aim is to provide absorbent fabrics that can further suppress slippage.

[0008] One method involves an absorbent article comprising: mutually orthogonal length and width directions; a front waist region, a rear waist region, and a crotch region disposed between the front waist region and the rear waist region; and an absorbent core disposed at least in the crotch region. In the front waist region and the rear waist region, a plurality of regions are provided, formed by dividing the front waist region and the rear waist region in the length direction. The plurality of regions include: a front waist region located at 0-25% of the total length of the front waist region extending rearward from the front edge of the front waist region; an upper abdominal region located at 25-50% of the total length of the front waist region extending rearward from the front edge of the front waist region; a lower abdominal region located at 50-85% of the total length of the front waist region extending rearward from the front edge of the front waist region; and a front waist region located at 85-100% of the total length of the front waist region extending rearward from the front edge of the front waist region. The lower back region is located at 0-25% of its total length in the forward direction from the rear edge of the aforementioned lower back region; the upper back region is located at 25-50% of its total length in the forward direction from the rear edge of the aforementioned lower back region; the lower back region is located at 50-85% of its total length in the forward direction from the rear edge of the aforementioned lower back region; and the hind leg region is located at 85-100% of its total length in the forward direction from the rear edge of the aforementioned lower back region. The tensile stress in the width direction of the aforementioned lower abdominal region is greater than the tensile stress in any region of the aforementioned front waist region. The tensile stress in the width direction of the aforementioned lower back region is greater than the tensile stress in any region of the aforementioned lower back region.

[0009] Other absorbent articles include: mutually orthogonal length and width directions; a front waist region, a rear waist region, and a crotch region disposed between the front waist region and the rear waist region; and an absorbent core disposed at least in the crotch region. In the front waist region and the rear waist region, multiple regions are provided that are divided along the length direction of the front waist region and the rear waist region. These multiple regions include: a front waist region located at 0-25% of the total length of the front waist region extending rearward from the front edge of the front waist region; an upper abdominal region located at 25-50% of the total length of the front waist region extending rearward from the front edge of the front waist region; a lower abdominal region located at 50-85% of the total length of the front waist region extending rearward from the front edge of the front waist region; and a front waist region located at 85-100% of the total length of the front waist region extending rearward from the front edge of the front waist region. The lower back region is located at 0-25% of its total length in the forward direction from the rear edge of the aforementioned lower back region; the upper back region is located at 25-50% of its total length in the forward direction from the rear edge of the aforementioned lower back region; the lower back region is located at 50-85% of its total length in the forward direction from the rear edge of the aforementioned lower back region; and the lower leg region is located at 85-100% of its total length in the forward direction from the rear edge of the aforementioned lower back region. The tensile stress in the width direction of the aforementioned lower back region is greater than the tensile stress in any other region. Attached Figure Description

[0010] Figure 1 This is a schematic front view of the absorbent article involved in this embodiment.

[0011] Figure 2 This is a schematic top view of the unfolded state of the absorbent article involved in this embodiment.

[0012] Figure 3 It is along Figure 1 The schematic cross-sectional view of F3-F3 shown.

[0013] Figure 4 It is a diagram that schematically shows the state of an absorbent item being worn by a wearer. Detailed Implementation

[0014] (1) Overview of the implementation method

[0015] Based on the description in this specification and the accompanying drawings, at least the following will become clear.

[0016] One type of absorbent article includes: mutually orthogonal length and width directions; a front waist region, a rear waist region, and a crotch region disposed between the front waist region and the rear waist region; and an absorbent core disposed at least in the crotch region. In the front waist region and the rear waist region, a plurality of regions are provided, formed by dividing the front waist region and the rear waist region in the length direction. The plurality of regions include: a front waist region located at 0-25% of the total length of the front waist region extending rearward from the front edge of the front waist region; an upper abdominal region located at 25-50% of the total length of the front waist region extending rearward from the front edge of the front waist region; a lower abdominal region located at 50-85% of the total length of the front waist region extending rearward from the front edge of the front waist region; and a front waist region located at 85-100% of the total length of the front waist region extending rearward from the front edge of the front waist region. The lower back region is located at 0-25% of its total length in the forward direction from the rear edge of the aforementioned lower back region; the upper back region is located at 25-50% of its total length in the forward direction from the rear edge of the aforementioned lower back region; the lower back region is located at 50-85% of its total length in the forward direction from the rear edge of the aforementioned lower back region; and the hind leg region is located at 85-100% of its total length in the forward direction from the rear edge of the aforementioned lower back region. The tensile stress in the width direction of the aforementioned lower abdominal region is greater than the tensile stress in any region of the aforementioned front waist region. The tensile stress in the width direction of the aforementioned lower back region is greater than the tensile stress in any region of the aforementioned lower back region. According to this method, the lower abdominal region, which abuts against the shortest part of the waist circumference in the abdomen, has the greatest tensile stress, and the lower back region, which abuts against the shortest part of the waist circumference in the back, has the greatest tensile stress. The part with the greatest stress abuts against the shortest part of the body's waist circumference. By applying maximum stress to the most concave part of the body, the longitudinal displacement of the absorbent material can be suppressed through its contraction. In other words, by placing a high-stress area in the concave part of the body, and by matching the body's shape with the stress level of the absorbent material, displacement of the absorbent material can be suppressed. Furthermore, the high-stress area in the lower back, because it is located near the flat back waist of the body, is less prone to longitudinal displacement during fitting, and thus easily maintains a suitable position.

[0017] Other absorbent articles include: mutually orthogonal length and width directions; a front waist region, a rear waist region, and a crotch region disposed between the front waist region and the rear waist region; and an absorbent core disposed at least in the crotch region. In the front waist region and the rear waist region, multiple regions are provided that are divided in the length direction of the front waist region and the rear waist region. These multiple regions include: a front waist region located at 0-25% of the total length of the front waist region extending rearward from the front edge of the front waist region; an upper abdominal region located at 25-50% of the total length of the front waist region extending rearward from the front edge of the front waist region; a lower abdominal region located at 50-85% of the total length of the front waist region extending rearward from the front edge of the front waist region; and a front waist region located at 85-100% of the total length of the front waist region extending rearward from the front edge of the front waist region. The lower back region is located at 0-25% of its total length in the forward direction from the rear edge of the aforementioned lower back region; the upper back region is located at 25-50% of its total length in the forward direction from the rear edge of the aforementioned lower back region; the lower back region is located at 50-85% of its total length in the forward direction from the rear edge of the aforementioned lower back region; and the lower leg region is located at 85-100% of its total length in the forward direction from the rear edge of the aforementioned lower back region. The tensile stress in the width direction of the aforementioned lower back region is greater than that in any other region. The lower back region, which abuts against the shortest part of the waist circumference in the back, experiences the greatest tensile stress, and the part with the greatest stress abuts against the shortest part of the body's waist circumference. By applying the greatest stress to the most concave part of the body, the longitudinal displacement of the absorbent material can be suppressed by the contraction of the absorbent material. Furthermore, because the tensile stress in the width direction of the lower back area is greater than that in any other area, it suppresses wearing pressure relative to the abdomen and increases wearing pressure on the back, thereby inhibiting displacement. It reduces pressure relative to the wearer's abdomen and improves comfort.

[0018] According to a preferred embodiment, the tensile stress in the width direction of the aforementioned lower back region is greater than the tensile stress in the width direction of the aforementioned lower abdomen region. The tensile stress is greatest in the lower abdomen region within the front waist region and greatest in the lower back region within the rear waist region. When worn, the lower abdomen region and the lower back region pull on each other. At this time, because the tensile stress in the lower back region is greater than that in the lower abdomen region, an upward force is applied from the center of the abdomen towards the side of the body. Therefore, even when absorbing bodily fluids such as urine, the force applied to the crotch area can suppress the sagging of the absorbent material.

[0019] According to a preferred embodiment, the tensile stress in the width direction of the upper back region is greater than the tensile stress in the width direction of the lower back region. According to this embodiment, the tensile stress in the back waist region gradually increases in the order of the lower back region, upper back region, and back waist region. The waist circumference on the back side gradually shortens upwards from the bulge of the buttocks. By increasing the stress on the absorbent material as the body's waist circumference decreases, the absorbent material conforms to the wearer's body shape, thus suppressing displacement of the absorbent material in the length direction.

[0020] According to a preferred embodiment, the tensile stress in the width direction of the lower back region is greater than the tensile stress in the width direction of the hind leg region. According to this embodiment, the tensile stress in the lower back region gradually increases in the order of the hind leg region, lower back region, upper back region, and lower back region. The waist circumference on the back side shortens from the bulge of the buttocks towards the groin. Therefore, the waist circumference of the portion where the lower back region is located is shorter than that of the portion where the hind leg region is located. However, the hind leg region is where the upper thigh is located and easily moves with the movement of the thigh. By setting the tensile stress in this hind leg region to be relatively small, the wearing comfort can be improved without hindering the movement of the upper thigh.

[0021] According to a preferred embodiment, the tensile stress in the width direction of the aforementioned front waist region is less than the tensile stress in the width direction of the aforementioned upper abdomen region. According to this embodiment, the tensile stress in the front waist region gradually decreases in the order of the lower abdomen region, upper abdomen region, and front waist region. By reducing the stress on the absorbent material as the body's waist circumference increases, the absorbent material can conform to the wearer's body shape, and displacement of the absorbent material in the length direction can be suppressed.

[0022] According to a preferred embodiment, the sum of the tensile stress in the width direction of the front waist region and the tensile stress in the width direction of the back waist region is greater than the sum of the tensile stress in the width direction of the lower abdomen region and the tensile stress in the width direction of the lower back region. In the wearing state, the front waist region and the back waist region are connected, and they cooperate to cover the wearer's waist circumference. The circumference of the wearer's waist tends to be shorter near the waist opening compared to the lower abdomen area. According to this embodiment, by increasing the sum of the tensile stress near the waist opening, a stress design that matches the circumference obtained by adding the front and back of the body can be achieved, thus suppressing the shifting of absorbent materials.

[0023] According to a preferred embodiment, the sum of the tensile stress in the width direction of the aforementioned front waist region and the aforementioned back waist region, as well as the sum of the tensile stress in the width direction of the aforementioned lower abdomen region and the aforementioned lower back region, is greater than the sum of the tensile stress in the width direction of the aforementioned upper abdomen region and the aforementioned upper back region. The waist circumference is shortest near the waist opening and lengthens from the waist opening towards the crotch. This lengthening is due to the bulge of the abdomen and the slope from the apex of the buttocks. The bulge of the abdomen and the slope from the apex of the buttocks mainly correspond to the upper abdomen region and the upper back region. The sum of the tensile stresses in the upper abdomen region and the upper back region is less than the sum of the tensile stresses in the front waist region and the aforementioned back waist region, thus preventing the bulge from constricting the body and allowing absorbent materials to be placed along the body. Furthermore, compared to the bulge of the abdomen and the slope from the apex of the buttocks towards the crotch, the waist circumference is shorter due to the concavity of the lower abdomen. The combined tensile stress in the lower abdomen and lower back regions is greater than the combined tensile stress in the upper abdomen and upper back regions, matching the concavity of the lower abdomen. The area from near the waist opening to the lower end of the abdomen is configured in proportion to the body circumference, which can suppress the deterioration of wearing comfort caused by localized tightness and can also suppress the overall shifting of absorbent materials.

[0024] According to a preferred embodiment, the sum of the tensile stress in the width direction of the lower back region and the tensile stress in the width direction of the upper back region is greater than the sum of the tensile stress in the width direction of the lower abdomen region and the tensile stress in the width direction of the foreleg region. According to this embodiment, the strong constriction relative to the concave areas of the abdomen and back can prevent slippage. Furthermore, the strong constriction on the back side compared to the abdomen increases the upward pulling force towards the back side, applying a force opposite to the downward displacement direction of the abdomen side. Therefore, the fall of the absorbent material 1 can be prevented.

[0025] According to the preferred embodiment, the total tensile stress in the width direction of the four regions of the lower back waist area is greater than the total tensile stress in the width direction of the four regions of the front waist area. The wearer's body shape differs between the abdominal and back sides, with the abdominal side bulging more than the back side. According to this embodiment, the total tensile stress in the multiple regions of the front waist area is smaller, preventing excessive constriction relative to the abdominal side where the body bulges more, while the total tensile stress in the multiple regions of the lower back waist area is larger. This allows the absorbent material to match the back side where the body bulges less, simultaneously improving comfort and suppressing shifting.

[0026] According to a preferred embodiment, the absorbent core has a low-basis-weight portion where the basis weight of the absorbent material is lower than that of the surrounding material. This low-basis-weight portion is positioned in an area overlapping with the lower abdominal region. According to this embodiment, the low-basis-weight portion allows the absorbent core to deform easily, making the lower abdominal region more conform to the body and further suppressing displacement in the front waist area.

[0027] (2) Overall general composition of absorbent materials

[0028] Hereinafter, the absorbent article according to the embodiment will be described with reference to the accompanying drawings. In the following description of the drawings, the same or similar parts are labeled with the same or similar reference numerals. It should be noted that the drawings are schematic views, and the proportions of the dimensions may differ from the actual dimensions. Therefore, specific dimensions should be determined by referring to the following description. Furthermore, the drawings may include parts with different dimensional relationships or proportions. Figure 1 This is a schematic front view of the absorbent article involved in this embodiment. Figure 2 This is a schematic top view of the unfolded state of the absorbent article involved in this embodiment. Figure 2 The diagram shows the elongated state of the absorbent article 1, which is stretched until no wrinkles are formed, with the lateral joints described later disengaged. Figure 3 It is along Figure 2 A schematic cross-sectional view of an absorbent article along line F3-F3. Additionally, for ease of explanation, some components are omitted from the diagram. Furthermore, for ease of explanation, even though the components are separated in the thickness direction, in actual products they are sometimes connected in the thickness direction.

[0029] The absorbent article 1 is, for example, a shorts-type disposable diaper, a band-type disposable diaper, or a shorts-type sanitary napkin. In this embodiment, the absorbent article 1 is a shorts-type disposable diaper. Figure 1 As shown, the absorbent article 1 has a length direction L and a width direction W orthogonal to the length direction L. The length direction L extends towards the front and back of the body. The absorbent article 1 has a thickness direction T orthogonal to both the length direction L and the width direction W. The thickness direction T extends towards the skin side T1 on the wearer's side and the non-skin side T2 on the opposite side.

[0030] The absorbent article 1 has: a front waist area S1 disposed on the abdomen of the wearer; a rear waist area S2 disposed on the back of the wearer; and a crotch area S3 disposed under the crotch of the wearer and between the front waist area S1 and the rear waist area. Figure 1 As shown, the absorbent article 1 may have a lateral joint 16 that joins the outer portion of the front waist region S1 and the outer portion of the rear waist region S2. Figure 1As shown, with the side joint 16 formed, the absorbent article 1 has a waist opening 17 for the wearer to pass through and a pair of leg openings 18 for the wearer's thighs to insert into. The waist opening 17 can be defined by the front edge S1F of the front waist region S1 and the rear edge S2R of the rear waist region S2.

[0031] In the shorts-type absorbent article 1, the crotch area S3 can be defined by the inner edge of the side joint 16 in the length direction L. The boundary between the front waist area S1 and the crotch area S3 can be defined by the rear end edge 16R of the side joint 16 in the front waist area S1. The boundary between the back waist area S2 and the crotch area S3 can be defined by the front end edge 16F of the side joint 16 in the back waist area S2. Alternatively, the crotch area S3 can also be defined by the area having a leg opening 18. The leg opening 18 is a portion recessed from the outer edge of the absorbent article 1 in the width direction W. The boundary between the front waist area S1 and the crotch area S3 can be defined by the front end edge of the leg opening 18. The boundary between the back waist area S2 and the crotch area S3 can be defined by the rear end edge of the leg opening 18.

[0032] In addition, in this specification, the outer portion refers to the part occupying a certain range in the width direction W, including the outer edge in the width direction W, and the outer edge refers to the outer edge in the width direction W. Similarly, the inner portion refers to the part occupying a certain range in the width direction W, including the inner edge in the width direction W, and the inner edge refers to the inner edge in the width direction W. Furthermore, in this specification, the front end and rear end are the parts occupying a certain range in the length direction L, including the edges in the length direction L, and the front edge and rear edge are the edges in the length direction L. The outer end includes the front end and rear end, and the outer edge includes the front edge and rear edge.

[0033] The absorbent article 1 may have an absorbent body 20 and an outer body 50. The absorbent body 20 may be separately constructed from the outer body 50. The absorbent body 20 is disposed at least in the crotch region S3. The absorbent body 20 may extend from the crotch region S3 toward at least the front waist region S1 in the length direction L, or it may extend throughout the front waist region S1, the back waist region S2, and the crotch region S3. Figure 3As shown, the absorbent body 20 overlaps with the outer body 50 in the thickness direction T in the front waist region S1 and the rear waist region S2. The outer body 50 is disposed at least in the front waist region S1 and the rear waist region S2. The absorbent body 20 may have an absorbent core 30, a surface sheet 41, a back sheet 42, and side sheets 47. The absorbent core 30 may have at least an absorbent core 31 containing absorbent material. The absorbent material may, for example, contain pulverized pulp or superabsorbent polymer (SAP), or mixtures thereof. The absorbent core 31 is disposed at least in the crotch region S3, and may also extend from the front waist region S1 to the rear waist region S2. The absorbent body 30 may have a core sheet 32 ​​covering the absorbent core 31. The core sheet 32 ​​may, for example, be made of thin paper or nonwoven fabric.

[0034] The absorber 30 may have a low-basis-weight section LR where the basis weight of the absorbent material is lower than that of the surrounding material. In this embodiment, in the low-basis-weight section LR, a core sheet 32 ​​is provided instead of an absorbent core 31 in the thickness direction T. Therefore, in this embodiment, the basis weight of the absorbent material in the low-basis-weight section LR is 0. Furthermore, "basis weight of the absorbent material is 0" means substantially 0, as long as the absorbent core 31 is substantially absent in the low-basis-weight section LR. In the low-basis-weight section LR, either a portion of the surrounding absorbent material may be present through inflow, or an absorbent material with a basis weight lower than that of the surrounding absorbent core 31 may be provided.

[0035] The surface sheet 41 is located on the skin-side T1 relative to the absorbent core 30. At least a portion of the surface sheet 41 (e.g., the portion not covered by the side sheet 47) is positioned in the absorbent article at the position closest to the skin-side T1, in contact with the wearer's skin. The surface sheet 41 only needs to be liquid-permeable, for example, it can be made of non-woven fabric. The back sheet 42 is located on the non-skin-side T2 relative to the absorbent core 30. The back sheet 42 only needs to be liquid-impermeable, for example, it can be made of film. The side sheet 47 is positioned outside the center of the absorbent core 31 in the width direction W. The side sheet 47 can be positioned on the skin-side T1 of the surface sheet. The side sheet 47 can be made of non-woven fabric, for example.

[0036] The outer body 50 can be disposed on the non-skin side T2 relative to the absorbent body 20. The outer body 50 can be composed of multiple sheets. The multiple sheets can be, for example, made of non-woven fabric. The outer body of the front waist region S1 and the outer body of the back waist region S2 can be separated in the length direction L. The outer body 50 can have a waist elastic member 55 disposed in the front waist region S1 and the back waist region S2 in a state of elongation in the width direction W. The waist elastic member 55 can be composed of a filamentous or rope-like elastic member extending in the width direction W, or it can be composed of a sheet-like elastic member.

[0037] The absorbent article 1 of this embodiment is configured to prevent slippage. The configuration for preventing slippage of the absorbent article 1 will now be described in detail. In the front waist region S1 and the rear waist region S2, multiple regions are provided, each divided along the length direction L by the front waist region S1 and the rear waist region S2. Each region is designed to generate appropriate tensile stress. Due to the difference in tensile stress, each region deforms in a different manner, making it difficult for the absorbent article 1 to slip off. The region comprises multiple areas: an anterior waist region F11 located at 0-25% of the total length L of the anterior waist region S1 extending backward from the front edge S1F of the anterior waist region S1; an upper abdominal region F12 located at 25-50% of the total length L of the anterior waist region S1 extending backward from the front edge S1F of the anterior waist region S1; a lower abdominal region F13 located at 50-85% of the total length L of the anterior waist region S1 extending backward from the front edge S1F of the anterior waist region S1; and a foreleg region located at 85-100% of the total length L of the anterior waist region S1 extending backward from the front edge S1F of the anterior waist region S1. Region F14; the lower back region R11 located at 0-25% of the total length of the lower back region S2 along the length L of the lower back region S2 extending forward from the rear end edge S2R of the lower back region S2; the upper back region R12 located at 25-50% of the total length of the lower back region S2 along the length L of the lower back region S2 extending forward from the rear end edge S2R of the lower back region S2; the lower back region R13 located at 50-85% of the total length of the lower back region S2 along the length L of the lower back region S2 extending forward from the rear end edge of the lower back region S2; and the lower leg region R14 located at 85-100% of the total length of the lower back region S2 along the length L of the lower back region S2 extending forward from the rear end edge of the lower back region S2.

[0038] Each region is a region of the outer casing 50. The specifications of each region and the determination of tensile stress can be performed by the following method. For the absorbent article 1 with the side joint 16, the side joint 16 is torn open to separate the front waist region S1 and the back waist region S2. Next, the absorbent body 20 is separated from the outer casing 50. After placing the outer casing 50 in an environment of 23°C ± 2°C and 50% ± 5% humidity for 2 hours, and stretching the outer casing 50 until no wrinkles are visible, marks are marked on the boundaries of the front waist region S1 and the back waist region S2. Based on these marks, the outer casing 50 is cut to obtain a test piece divided into multiple regions. Next, the two ends (5mm wide) of the cut test piece are clamped by the clamps (clamping devices) of a tensile testing machine (Instron testing machine). At this time, the distance between the clamps is set to 100mm. Next, with one of the clamps in the width direction W fixed, the other clamp is moved by changing the distance between the clamps. The moving speed of the clamp is set to 254 mm / min. During the clamp movement, the stress applied to the clamp is measured, and the stress (N / mm) obtained when stretched by 70% (a certain width) from the elongated state is defined as "tensile stress". The measurement data of tensile stress obtained in the absorbent article 1 according to Examples 1 and 2 are shown in Table 1.

[0039] [Table 1]

[0040] Unit N / mm

[0041] Example 1 Example 2 Example 1 Example 2 F11 0.0104 0.0092 R11 0.0394 0.0402 F12 0.0113 0.0100 R12 0.0271 0.0268 F13 0.0292 0.0260 R13 0.0140 0.0157 F14 0.0075 0.0067 R14 0.0078 0.0050 total 0.0583 0.0520 0.0882 0.0877

[0042] Figure 4 This is a schematic diagram showing the state of the absorbent item 1 being worn by a wearer. Figure 4 This diagram shows the wearer in a standing, side-view position. The wearer's body lines are represented by a single-dotted line BL. Figure 4As shown, the wearer's body shape differs on the abdominal and back sides, and the waist circumference varies along the length L of the absorbent article 1. Through in-depth research, the applicant discovered that the waist circumference is shortest near the lower abdomen, increasing upwards from the lower abdomen and towards the groin. Conversely, on the wearer's back, the waist circumference shortens as it moves upwards from the buttocks, with less variation near the waist (the narrowest part of the waist), resulting in a generally flat shape with minimal outward bulges. Areas of high stress in the absorbent article 1 are in close contact with the body. For example, if a high-stress area is in close contact with the longer part of the waist circumference, the high-stress area will shift towards the shorter part due to the contraction of the absorbent article 1, sometimes causing displacement of the absorbent article 1. However, in this embodiment, the tensile stress in the width W of the lower abdominal region F13 is greater than the tensile stress in any area of ​​the front waist region S1. That is, the tensile stress relationships satisfy F13 > F11, F13 > F12, and F13 > F14. Furthermore, the tensile stress in the width direction W of the lower back region R11 is greater than the tensile stress in any region of the lower back region S2. That is, the tensile stress relationships satisfy R11 > R12, R11 > R13, and R11 > R14. The lower abdominal region F13, which abuts against the shortest part of the waist circumference in the abdomen, has the greatest tensile stress, and the lower back region R11, which abuts against the shortest part of the waist circumference in the back, has the greatest tensile stress. The region with the greatest stress abuts against the shortest part of the body's waist circumference. By aligning the region with the most concave part of the body, the absorbent material 1 conforms to the shape of the body through contraction, thus suppressing displacement of the absorbent material 1 in the length direction L. That is, by placing a region with high stress in the concave part of the body, the shape of the body is proportionate to the degree of wearing pressure generated by the stress of the absorbent material 1, thus suppressing displacement of the absorbent material 1. Furthermore, since the lower back region R11, which experiences greater stress, matches the waist area on the back side of the body, which is in a flat shape, it is difficult for the length direction L to shift during the matching process, and it is easy to maintain the position of the suitable absorbent material 1 continuously.

[0043] The tensile stress in the width direction W of the upper back region R12 can be greater than the tensile stress in the width direction W of the lower back region R13. That is, the tensile stress relationship can satisfy R12 > R13. The tensile stress of the back waist region S2 gradually increases in the order of lower back region R13, upper back region R12, and lower back region R11. The lower back region R13 covers the bulging part of the wearer's buttocks. The waist circumference on the back side gradually shortens from the bulging part of the buttocks upwards. As the body's waist circumference decreases, the stress on the absorbent material 1 increases, thereby making the absorbent material 1 conform to the wearer's body shape and suppressing the displacement of the absorbent material 1 in the length direction L. In addition, the lower back region R13 is positioned opposite to the excrement. If the tensile stress of the lower back region R13 is large, the excrement will be in close contact with the body, which may worsen the wearing experience. However, compared to the lower back area R11 and upper back area R12, the lower back area R13 experiences less stress and does not adhere tightly to the body. Therefore, it does not cause excrement to adhere closely to the body and can continuously absorb it, thus preventing a deterioration in wearing comfort. Furthermore, the bulging portion of the buttocks covered by the lower back area R13 is an area where the body is prone to movement during activity. Because the absorbent material 1 does not adhere excessively to this area where the body is prone to movement, the absorbent material 1 is less likely to wrinkle due to body movement, thus preventing shifting.

[0044] The tensile stress in the width direction W of the lower back region R13 can be greater than the tensile stress in the width direction W of the rear leg region R14. That is, the tensile stress relationship can satisfy R13 > R14 and R11 > R12 > R13 > R14. The tensile stress of the rear waist region S2 gradually increases in the order of rear leg region R14, lower back region R13, upper back region R12, and rear waist region R11. The waist circumference on the back side shortens from the bulge of the buttocks towards the lower groin. Therefore, the waist circumference of the part with the lower back region R13 is shorter than that of the part with the rear leg region R14. However, the rear leg region R14 is the area where the upper thigh is located and easily moves with the movement of the thigh. By setting the tensile stress of this rear leg region R14 to be smaller, the movement of the upper thigh will not be hindered, and the wearing comfort can be improved.

[0045] The tensile stress in the width direction W of the front waist region F11 can be less than the tensile stress in the width direction W of the upper abdomen region F12. That is, the tensile stress relationship can satisfy F11 < F12. The waist circumference of the wearer's abdomen is shortest at the concave part of the lower abdomen and increases as it moves upward from that concave part. The tensile stress of the front waist region S1 gradually decreases in the order of lower abdomen region F13, upper abdomen region F12, and front waist region F11. By reducing the stress of the absorbent material 1 as the body's waist circumference increases, the absorbent material 1 conforms to the wearer's body shape, and displacement of the absorbent material 1 in the length direction L can be suppressed. In addition, the bulging part of the abdomen covered by the front waist region F11 is a part of the body that is prone to movement during movement. Since the absorbent material 1 does not fit too tightly against this part of the body that is prone to movement during movement, the absorbent material 1 is less likely to wrinkle due to body movement, and displacement can be suppressed.

[0046] The tensile stress in the width direction W of the lower abdominal region F13 can be less than or equal to the sum of the tensile stress in the width direction W of the front waist region F11, the upper abdominal region F12, and the front leg region F14. That is, the tensile stress relationship can satisfy F13 < F11 + F12 + F14 or F13 = F11 + F12 + F14. If the tensile stress in the lower abdominal region F13 becomes too large compared to the surrounding areas, although it can suppress the slippage of the absorbent material 1, there is a possibility that the wearing comfort will deteriorate due to localized tightness. The tensile stress in the lower abdominal region F13 is less than or equal to the sum of the tensile stresses in the other areas of the front waist region S1. Therefore, relative to the overall wearing pressure of the front waist region S1, the lower abdominal region F13 will not protrude too much, which can suppress discomfort and prevent slippage.

[0047] The tensile stress relationship in the front waist area S1 can satisfy F13>F12>F11>F14. The tensile stress relationship can be configured in proportion to the waist circumference of the abdomen, so that the absorbent material 1 can match the shorter lower abdominal area F13, and the stress is reduced in the front leg area F14, which is prone to leaving marks on the leg elastic members, so as not to tighten the area near the thighs and improve the wearer's wearing comfort.

[0048] The tensile stress in the width direction W of the lower back region R11 is greater than that in any other region. That is, the tensile stress relationships satisfy R11 > R12, R11 > R13, R11 > R14, R11 > F11, R11 > F12, R11 > F13, and R11 > F14. By aligning the maximum stress with the most concave part of the back, the contraction of the absorbent material 1 can suppress displacement of the absorbent material 1 in the length direction L. Furthermore, since the tensile stress in the width direction W of the lower back region R11 is greater than that in any other region, wearing pressure relative to the abdomen is reduced, and wearing pressure on the back is increased, thereby suppressing displacement. This reduces pressure relative to the wearer's abdomen and improves comfort.

[0049] The total tensile stress in the width direction (W) of the four regions of the back waist area S2 can be greater than the total tensile stress in the width direction (W) of the four regions of the front waist area S1. That is, the tensile stress relationship satisfies R11+R12+R13+R14>F11+F12+F13+F14. The wearer's body shape differs between the abdomen and back, with the abdomen bulging more than the back. The total tensile stress in the multiple regions of the front waist area S1 is relatively small, so it is not too constricting relative to the more bulging abdomen. Conversely, the total tensile stress in the multiple regions of the back waist area S2 is relatively large, and the absorbent material 1 matches the less bulging back, simultaneously improving comfort and inhibiting shifting.

[0050] The sum of the tensile stress in the width direction W of the front waist region F11 and the tensile stress in the width direction W of the back waist region R11 can be greater than the sum of the tensile stress in the width direction W of the lower abdomen region F13 and the tensile stress in the width direction W of the lower back region R13. That is, the tensile stress relationship can satisfy F11+R11>F13+R13. In the wearing state, the front waist region S1 and the back waist region S2 are connected, and the two cooperate to cover the wearer's waist circumference. The circumference of the wearer's waist tends to be shorter near the waist opening compared to the lower abdomen. By increasing the sum of the tensile stress near the waist opening, a stress design that matches the circumference obtained by adding the front and back of the body can be achieved, which can suppress the displacement of the absorbent material 1.

[0051] The sum of the tensile stress in the width direction (W) of the front waist region (F11) and the rear waist region (R11), and the sum of the tensile stress in the width direction (W) of the lower abdomen region (F13) and the lower back region (R13) can be greater than the sum of the tensile stress in the width direction (W) of the upper abdomen region (F12) and the upper back region (R12). That is, the tensile stress relationship satisfies F11+R11>F12+R12 and F13+R13>F12+R12. The waist circumference is shortest near the waist opening and lengthens towards the hips. This lengthening is due to the protrusion of the abdomen and the slope from the apex of the buttocks. The protrusion of the abdomen and the slope from the apex of the buttocks mainly correspond to the upper abdomen region (F12) and the upper back region (R12). The combined tensile stress of the upper abdominal region F12 and the upper back region R12 is less than the combined tensile stress of the front waist region F11 and the rear waist region R11. Therefore, it does not constrict the body's bulge, and the absorbent material 1 is positioned along the body. The waist circumference is shorter due to the concavity of the lower abdomen compared to the bulge of the abdomen and the slope from the top of the buttocks towards the groin. The combined tensile stress of the lower abdominal region F13 and the lower back region R13 is greater than the combined tensile stress of the upper abdominal region F12 and the upper back region R12, matching the concavity of the lower abdomen. The area from near the waist opening to the lower end of the abdomen is positioned proportionally to the body circumference, suppressing the deterioration of wearing comfort caused by localized constriction and preventing overall displacement of the absorbent material 1.

[0052] The sum of the tensile stress in the width direction W of the lower back region R11 and the upper back region R12 can be greater than the sum of the tensile stress in the width direction W of the lower abdomen region F13 and the hind leg region R14. That is, the tensile stress relationship satisfies R11+R12>R13+R14. The shape of the back is concave on the upper side, and the lower back region R11 and the upper back region R12 are relatively concave areas on the back. By matching the concave part of the back with strong stress, the displacement of the absorbent article 1 is suppressed. In addition, the sum of the tensile stress in the width direction W of the front waist region F11 and the upper abdomen region F12 can be greater than the sum of the tensile stress in the width direction W of the lower abdomen region F13 and the front leg region F14. That is, the tensile stress relationship satisfies F11+F12<F13+F14. The abdomen is concave in shape on the lower side, with the lower abdominal region F13 and the foreleg region F14 being relatively concave areas of the abdomen. By applying strong stress to these concave areas of the abdomen, displacement of the absorbent material 1 is suppressed. The sum of the tensile stress in the lower back region R11 and the upper back region R12 can be greater than the sum of the tensile stress in the width direction W of the lower abdominal region F13 and the foreleg region F14. The tensile stress relationship satisfies R11+R12>F13+F14. The lower back region R11 and the upper back region R12 are relatively concave areas of the back. In addition, the lower abdominal region F13 and the foreleg region F14 are relatively concave areas of the abdomen. By forcefully tightening the concave areas of the abdomen and back, slippage can be suppressed. Furthermore, by forcefully tightening the back side compared to the abdominal side, the upward pulling force towards the back side can be increased, applying a force opposite to the downward displacement direction of the abdominal side. Therefore, it can suppress the falling of absorbent material 1.

[0053] The tensile stress in the width direction W of the lower back region R11 can be greater than the tensile stress in the width direction W of the lower abdomen region F13. That is, the tensile stress relationship can satisfy R11 > F13. In the front waist region S1, the tensile stress in the lower abdomen region F13 is the greatest, and in the lower back region S2, the tensile stress in the lower back region R11 is the greatest. When worn, the lower abdomen region F13 and the lower back region R11 pull on each other. At this time, since the tensile stress in the lower back region R11 is greater than the tensile stress in the lower abdomen region F13, an upward force is applied from the center of the abdomen towards the side of the body. Therefore, even when there is a force acting on the crotch area side during the absorption of body fluids such as urine, the downward movement of the absorbent material 1 can be suppressed.

[0054] The tensile stress in the width direction W of the upper back region R12 can be greater than the tensile stress in the width direction W of the lower abdomen region F13. That is, the tensile stress relationship can satisfy R12 > F13. When worn, the lower abdomen region F13 and the upper back region R12 pull on each other. At this time, since the tensile stress in the upper back region R12 is greater than the tensile stress in the lower abdomen region F13, a force is applied obliquely upward from the center of the abdomen towards the side of the body. Therefore, even when there is a force acting on the side of the crotch area during the absorption of body fluids such as urine, the downward movement of the absorbent material 1 can be suppressed.

[0055] The tensile stress in the width direction W of the lower abdominal region F13 can be greater than the tensile stress in the width direction W of the lower back region R13. That is, the tensile stress relationship can satisfy F13 > R13. The lower abdominal region F13 and the lower back region R13 are pulled towards each other via the lateral joint 16. At this time, since the tensile stress relationship satisfies F13 > R13, the lower waist region S2 is pulled towards the front waist region S1 by the lower abdominal region F13 with relatively large tensile stress, which can further improve the matching with respect to the lower abdomen. In addition, in the back, since the tensile stress in the lower waist region R11 is relatively large, an upward force is generated, which can suppress the slippage of the absorbent material 1.

[0056] The tensile stress in the width direction W of the upper back region R12 can be greater than the tensile stress in the width direction W of the upper abdomen region F12. That is, the tensile stress relationship can satisfy R12 > F12. Furthermore, it is preferable that the tensile stress in the width direction W of the upper back region R12 can be more than twice the tensile stress in the width direction W of the upper abdomen region F12. Regarding body shape, the portion above the apex of the buttocks that contacts the upper back region R12 is concave, while the portion above the lower end of the abdomen where the upper abdomen region F12 is located is bulging. The difference in waist circumference between the area concave relative to the apex of the buttocks and the area bulging relative to the lower end of the abdomen tends to increase. By ensuring that the tensile stress relationship satisfies R12 > F12, a stress configuration more suitable to the body shape can be achieved, and the slippage of the absorbent material 1 can be suppressed.

[0057] The sum of the tensile stress in the width direction W of the lower back region R11 and the tensile stress in the width direction W of the upper back region R12 can be greater than or equal to the sum of the tensile stress in the width direction W of the front waist region F11 and the tensile stress in the width direction W of the upper abdomen region F12. According to this method, the back side is strongly tightened relative to the concave portion of the body shape, compared to the abdominal side, thereby applying a force opposite to the downward displacement direction of the abdominal side, thus suppressing the slippage of the absorbent material 1.

[0058] In addition to the stress differences in the regions of the outer casing 50, the composition of the absorbent body 20 can also be modified to suppress displacement of the absorbent article. More specifically, the low-weight section LR can be positioned in the region overlapping with the lower abdominal region F13. The low-weight section LR facilitates the deformation of the absorbent core 31, making the lower abdominal region F13 more closely match the concave area at the lower end of the abdomen, further suppressing displacement of the front waist region S1. Furthermore, the low-weight section LR can be positioned not only in the lower abdominal region F13, but also distributed throughout other regions.

[0059] Furthermore, the structure that increases stress in each region can be achieved, for example, by increasing the elongation ratio of the elastic member disposed in the waist section of the outer casing. Alternatively, by increasing the number of filamentous or rope-like elastic members 55 in the waist section. Alternatively, by increasing the number of filamentous elastic members disposed in the waist section of the outer casing. Conversely, the structure that reduces stress in each region can be achieved by using a structure opposite to that that increases stress.

[0060] The present invention has been described in detail above using the embodiments described above. However, it should be understood by those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented in modified and altered ways without departing from the concept and scope of the present invention as defined in the claims. Therefore, the purpose of this specification is illustrative and not intended to be restrictive in any way.

[0061] Furthermore, the entire contents of Japanese Patent Application No. 2020-185283, filed on November 5, 2020, are incorporated herein by reference.

[0062] Industrial applicability

[0063] Absorbent materials can be provided to prevent them from slipping off.

[0064] Explanation of reference numerals in the attached figures

[0065] 1: Absorbent material, 31: Absorbent core, LR: Low base weight area, F11: Front waist area, F12: Upper abdomen area, F13: Lower abdomen area, F14: Front leg area, R11: Lower waist area, R12: Upper back area, R13: Lower back area, R14: Lower leg area, S1: Front waist area, S1F: Front edge, S2: Lower waist area, S2R: Rear edge, S3: Crotch area, L: Length direction, W: Width direction.

Claims

1. An absorbent article having: The length and width directions are mutually orthogonal; The front waist area, the back waist area, and the crotch area located between the front waist area and the back waist area; and At least the absorbent core is configured in the crotch area, wherein, In the aforementioned front waist region and the aforementioned back waist region, there are multiple areas formed by dividing the aforementioned front waist region and the aforementioned back waist region along the aforementioned length direction. The aforementioned regions include: a front waist region located at 0-25% of the total length of the front waist region extending backward from its front edge; an upper abdominal region located at 25-50% of the total length of the front waist region extending backward from its front edge; a lower abdominal region located at 50-85% of the total length of the front waist region extending backward from its front edge; and a front waist region located at 85-100% of the total length of the front waist region extending backward from its front edge. The leg area; the lower back area located at 0-25% of the total length of the lower back area extending forward from the rear edge of the lower back area; the upper back area located at 25-50% of the total length of the lower back area extending forward from the rear edge of the lower back area; the lower back area located at 50-85% of the total length of the lower back area extending forward from the rear edge of the lower back area; and the hind leg area located at 85-100% of the total length of the lower back area extending forward from the rear edge of the lower back area. The tensile stress in the width direction of the lower abdominal region is greater than the tensile stress in the width direction of any region of the front waist region. The tensile stress in the width direction of the aforementioned lower back region is greater than the tensile stress in the width direction of any region of the aforementioned lower back circumference. The tensile stress in the width direction of the upper back region is greater than the tensile stress in the width direction of the lower back region. The tensile stress in the width direction of the lower back region is greater than the tensile stress in the width direction of the hind leg region. The tensile stress in the width direction of the upper back region is greater than the tensile stress in the width direction of the lower abdomen region, and the tensile stress in the width direction of the lower abdomen region is greater than the tensile stress in the width direction of the lower back region.

2. An absorbent article, the absorbent article having: The length and width directions are mutually orthogonal; The front waist area, the back waist area, and the crotch area located between the front waist area and the back waist area; and At least the absorbent core is configured in the crotch area, wherein, In the aforementioned front waist region and the aforementioned back waist region, there are multiple areas formed by dividing the aforementioned front waist region and the aforementioned back waist region along the aforementioned length direction. The aforementioned regions include: a front waist region located at 0-25% of the total length of the front waist region extending backward from its front edge; an upper abdominal region located at 25-50% of the total length of the front waist region extending backward from its front edge; a lower abdominal region located at 50-85% of the total length of the front waist region extending backward from its front edge; and a front waist region located at 85-100% of the total length of the front waist region extending backward from its front edge. The leg area; the lower back area located at 0-25% of the total length of the lower back area extending forward from the rear edge of the lower back area; the upper back area located at 25-50% of the total length of the lower back area extending forward from the rear edge of the lower back area; the lower back area located at 50-85% of the total length of the lower back area extending forward from the rear edge of the lower back area; and the hind leg area located at 85-100% of the total length of the lower back area extending forward from the rear edge of the lower back area. The tensile stress in the width direction of the aforementioned lower back region is greater than the tensile stress in the width direction of any other region. The tensile stress in the width direction of the upper back region is greater than the tensile stress in the width direction of the lower abdomen region, and the tensile stress in the width direction of the lower abdomen region is greater than the tensile stress in the width direction of the lower back region.

3. The absorbent article according to claim 2, wherein, The tensile stress in the width direction of the aforementioned lower back region is greater than the tensile stress in the width direction of the aforementioned lower abdomen region.

4. The absorbent article according to claim 2 or 3, wherein, The tensile stress in the width direction of the upper back region is greater than the tensile stress in the width direction of the lower back region.

5. The absorbent article according to claim 4, wherein, The tensile stress in the width direction of the lower back region is greater than the tensile stress in the width direction of the hind leg region.

6. The absorbent article according to claim 1 or 2, wherein, The tensile stress in the width direction of the aforementioned front waist region is less than the tensile stress in the width direction of the aforementioned upper abdomen region.

7. The absorbent article according to claim 1 or 2, wherein, The sum of the tensile stress in the width direction of the aforementioned front waist region and the tensile stress in the width direction of the aforementioned rear waist region is greater than the sum of the tensile stress in the width direction of the aforementioned lower abdomen region and the tensile stress in the width direction of the aforementioned lower back region.

8. The absorbent article according to claim 7, wherein, The sum of the tensile stress in the width direction of the aforementioned front waist region and the tensile stress in the width direction of the aforementioned rear waist region, as well as the sum of the tensile stress in the width direction of the aforementioned lower abdomen region and the tensile stress in the width direction of the aforementioned lower back region, is greater than the sum of the tensile stress in the width direction of the aforementioned upper abdomen region and the tensile stress in the width direction of the aforementioned upper back region.

9. The absorbent article according to claim 1 or 2, wherein, The sum of the tensile stress in the width direction of the lower back region and the tensile stress in the width direction of the upper back region is greater than the sum of the tensile stress in the width direction of the lower abdomen region and the tensile stress in the width direction of the foreleg region.

10. The absorbent article according to claim 1 or 2, wherein, The sum of the tensile stresses in the width direction of the four regions of the rear waist area is greater than the sum of the tensile stresses in the width direction of the four regions of the front waist area.

11. The absorbent article according to claim 1 or 2, wherein, The aforementioned absorbent core has a low-basis-weight portion where the basis weight of the absorbent material is lower than that of the surrounding material. The aforementioned low-base heavy part is located in the area that overlaps with the aforementioned lower abdominal region.

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