Absorbent articles

Abstract

To provide an absorbent article that can achieve both improved fit and prevention of slippage, and the prevention of skin problems for the wearer. [Solution] The absorbent article 1 comprises a ventral portion 3, a dorsal portion 2, and an absorbent body 4 including an absorbent material 8. The ventral portion 3 and the dorsal portion 2 are joined together to form a waist portion. The front and rear ends of the absorbent body 4 extend to the central portion in the width direction of the ventral portion 3 and the dorsal portion 2, respectively. The waist portion includes elastic members 12 and 13 that expand and contract in the width direction. The return stress in the width direction of the waist portion is 0.010 N / mm to 0.030 N / mm or less. An anti-slip agent SC is applied to the skin-contacting surface of the waist portion.

Description

[Technical Field]

[0001] This invention relates to absorbent articles. [Background technology]

[0002] Absorbent articles are known that have a waist circumference composed of an ventral portion and a dorsal portion. Such absorbent articles fit snugly around the wearer's waist so as not to shift and can be easily put on like underwear.

[0003] Up until now, in order to further improve fit and prevent slippage, various improvements have been made to the waist area, such as adjusting the stress of elastic members according to the area. For example, Patent Document 1 discloses a pant-type disposable diaper having an abdominal portion, a crotch portion and a dorsal portion, and having a pair of side seals, a waist opening and a pair of leg openings. In this disposable diaper, the area between the upper imaginary line connecting the upper ends of the uppermost elastic members in each of the pair of side seals and the lower imaginary line connecting the lower ends of the lowermost elastic members in each of the pair of side seals is divided into four band-shaped areas of the same width extending in the diaper width direction. These four band-shaped areas are designated as the 1st region, 2nd region, 3rd region, and 4th region in order from the upper imaginary line side to the lower imaginary line side. At that time, the contraction force of each region when wearing the diaper is greater in the 2nd region than in the 3rd region, greater in the 4th region than in the 3rd region, and greater in the 2nd region than in the 1st region. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 5144229 [Overview of the project] [Problems that the invention aims to solve]

[0005] In absorbent materials, to further improve fit and prevent slippage, one possible method is to increase the stress of the elastic material included in the waist area to a certain extent, thereby tightening the wearer's waist area to a certain degree.

[0006] However, in such cases, the skin of the wearer's waist may be strongly compressed by the material that makes up the skin-contacting surface around the waist. This can put a strain on the skin due to the pressure, and if slippage occurs, the stratum corneum and sebum of the skin may peel off from the skin surface. This can reduce the skin's barrier function and potentially cause skin problems such as eczema and dry skin. Such skin problems can also occur in disposable diapers described in Patent Document 1, in which the stress of the elastic material is adjusted according to the area. In other words, when the waist is tightened to some extent to improve fit and prevent slippage, adjusting only the elastic material around the waist has its limits in preventing skin problems. This tendency is particularly pronounced in infants with sensitive skin or infants who are very active.

[0007] To minimize skin irritation, one might consider using a larger size disposable diaper to reduce friction between the material that makes up the skin-contacting surface around the waist and the wearer's skin. However, while this may reduce skin irritation, it could also reduce the fit, causing the diaper to become loose and shift from its proper position, potentially leading to urine leakage.

[0008] To prevent slipping, methods such as using materials that increase friction between the skin and the absorbent material, or using devices like suspenders, could be considered. However, the former makes it difficult to prevent skin problems, and the latter significantly increases the amount of material used, making them impractical solutions for disposable products.

[0009] Therefore, the object of the present invention is to provide an absorbent article that can achieve both improved fit and prevention of slippage, and prevention of skin problems for the wearer. [Means for solving the problem]

[0010] The absorbent article of the present invention has longitudinal, widthwise, and thicknesswise directions that are mutually orthogonal when unfolded, and comprises an abdominal portion that covers the wearer's abdomen, a dorsal portion that covers the wearer's back, and an absorbent body that covers the wearer's groin and includes an absorbent material, wherein the abdominal portion and the dorsal portion are joined together at both ends in the widthwise direction along the longitudinal direction to form a waist portion, and the absorbent body has front and rear ends in the longitudinal direction that extend to the central portion in the widthwise direction of the abdominal portion and the dorsal portion, respectively, wherein the waist portion includes an elastic member that expands and contracts in the widthwise direction, the return stress in the widthwise direction of the waist portion is 0.010 N / mm to 0.030 N / mm or less, and an anti-slip agent is applied to the skin-contacting surface of the waist portion. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an absorbent article that can achieve both improved fit and prevention of slippage, as well as prevention of skin problems for the wearer. [Brief explanation of the drawing]

[0012] [Figure 1] This is a plan view showing an example of the structure of an absorbent article according to an embodiment, in an unfolded state. [Figure 2] This is a cross-sectional view along the longitudinal centerline CL in Figure 1. [Figure 3] This is a cross-sectional view along the widthwise centerline CW in Figure 1. [Figure 4] Figure 1 is a plan view showing an example of application of the anti-slip agent in an unfolded state. [Figure 5] Figure 1 is a plan view showing another application example of the anti-slip agent in an unfolded state. [Figure 6] Figure 1 is a plan view showing another application example of the anti-slip agent in an unfolded state. [Figure 7] Figure 1 is a plan view showing another application example of the anti-slip agent in an unfolded state. [Figure 8] It is a schematic diagram showing a method for measuring the return stress. [Figure 9] It is a schematic diagram showing a method for measuring the sliding tensile stress.

Mode for Carrying Out the Invention

[0013] This embodiment relates to the following aspects.

[0014] [Aspect 1] It has a longitudinal direction, a width direction, and a thickness direction that are orthogonal to each other in the unfolded state, and includes a ventral part that covers the abdomen of the wearer, a dorsal part that covers the back, and an absorbent body that covers the crotch of the wearer and includes an absorber. The ventral part and the dorsal part are joined to each other along the longitudinal direction at both ends in the width direction to form a body circumference part. The absorbent body is an absorbent article in which the front and rear ends in the longitudinal direction extend to the central parts in the width direction of the ventral part and the dorsal part, respectively. The body circumference part includes an elastic member that expands and contracts in the width direction, the return stress of the body circumference part in the width direction is 0.010 N / mm to 0.030 N / mm, and an anti-slip agent is applied to the skin contact surface of the body circumference part.

[0015] In this absorbent article, the waist portion includes an elastic member that expands and contracts in the width direction. This ensures a good fit between the waist portion and, consequently, the absorbent article, to the wearer's waist. Because the return stress in the width direction of the waist portion is low (0.010 N / mm to 0.030 N / mm), pressure and chafing against the wearer's skin caused by the skin-contacting material of the waist portion, including the elastic member, can be suppressed. Furthermore, the application of an anti-slip agent to the skin-contacting surface of the waist portion, i.e., the presence of the anti-slip agent between the waist portion and the skin, suppresses chafing between the material and the skin. These factors help to reduce skin problems for the wearer. Simultaneously, the presence of the anti-slip agent between the waist portion and the skin prevents the absorbent article from slipping off the wearer's waist, even with low return stress in the width direction of the waist portion. Therefore, this absorbent article improves fit and prevents slipping while simultaneously reducing skin problems for the wearer. (Furthermore, a return stress of 0.010 N / mm or higher suppresses slippage through a synergistic effect with the anti-slip agent, and a return stress of 0.030 N / mm or lower suppresses the occurrence of skin problems caused by pressure on the skin.)

[0016] [Aspect 2] The shear prevention agent is an absorbent article according to Embodiment 1, wherein the shear prevention agent contains 45% by mass or more of a hygroscopic humectant under conditions of a temperature of 20°C and a relative humidity of 60%RH.

[0017] This absorbent article contains 45% by mass or more of a hygroscopic humectant as an anti-slip agent under conditions of 20°C and 60% RH relative humidity. Therefore, although not limited to the mechanism described below, it is believed that hydrogen bonds are formed between the hygroscopic humectant and the moisture on the skin surface, creating surface tension between at least one of the anti-slip agents on the ventral and dorsal sides and the wearer's waist. As a result, even with low return stress in the width direction of the waist area, the absorbent article can be more effectively prevented from slipping off the wearer's waist. In addition to this effect of preventing slippage, the hygroscopic humectant interposed between the waist area material and the skin of the waist can suppress friction between the material and the skin, thereby reducing skin problems for the wearer.

[0018] [Aspect 3] The absorbent article according to embodiment 2, wherein the hygroscopic humectant contains glycerin.

[0019] In this absorbent article, the inclusion of glycerin as a hygroscopic humectant allows the hygroscopic humectant to be more reliably effective. Specifically, surface tension prevents slippage, so even with low return stress in the width direction of the waist area, the absorbent article is less likely to slip off the wearer's waist. Furthermore, the glycerin acts as an intermediary between the waist area material and the skin of the waist, suppressing friction between the material and the skin, thus reducing skin problems for the wearer.

[0020] [Aspect 4] The basis weight of the aforementioned anti-slip agent is 0.3 g / m². 2 More than 2.5g / m 2 The absorbent article described in any one of the following embodiments 1 to 3.

[0021] In this absorbent article, the basis weight of the shear prevention agent is 0.3 g / m². 2 More than 2.5g / m 2 The following applies: The basis weight of the anti-slip agent is the lower limit (0.3 g / m²). 2 By having a basis weight of 2.5 g / m² or more, surface tension can be more reliably generated between the waist area and the wearer's waist. 2 By keeping the amount below the upper limit, the anti-slip agent will not become sticky when worn. Furthermore, by keeping the amount below the upper limit, it will prevent the lubrication effect from outweighing the anti-slip effect, which could actually cause the item to slip down. Therefore, the optimal amount of anti-slip agent can achieve both anti-slip effect and reduced stickiness.

[0022] [Aspect 5] An absorbent article according to any one of embodiments 1 to 4, wherein in a sliding tensile test, the sliding tensile stress is 0.10 N / mm or more and 0.12 N / mm or less.

[0023] In this absorbent material, the sliding tensile stress in the sliding tensile test is 0.10 N / mm or higher. This prevents the absorbent material, which becomes heavier after absorbing excreted urine, from slipping down from the wearer's waist. As a result, slippage can be more reliably suppressed despite the low return stress in the width direction of the waist area. On the other hand, the sliding tensile stress is 0.12 N / mm or lower. This can more reliably suppress the occurrence of skin problems caused by skin compression.

[0024] [Aspect 6] The absorbent article according to any one of embodiments 1 to 5, wherein in a sliding tensile test, the sliding tensile stress is 1.05 times or more and 1.25 times or less the sliding tensile stress when the anti-slip agent is not applied to the skin-contacting surface of the body portion.

[0025] In this absorbent article, the sliding tensile stress in the sliding tensile test is 1.05 times or more the sliding tensile stress when no anti-slip agent is applied to the skin-contact surface around the waist. This prevents the absorbent article, which becomes heavier after absorbing excreted urine, from slipping down from the wearer's waist. As a result, slippage can be more reliably suppressed despite the low return stress in the width direction around the waist. On the other hand, the sliding tensile stress is 1.25 times or less the sliding tensile stress when no anti-slip agent is applied to the skin-contact surface around the waist. This suppresses the occurrence of skin problems caused by skin compression, thus more reliably preventing skin problems.

[0026] [Aspect 7] The absorbent article according to any one of embodiments 1 to 6, wherein the anti-slip agent is applied continuously or intermittently from one end to the other in the width direction on at least one of the ventral and dorsal portions.

[0027] In this absorbent article, an anti-slip agent is continuously or intermittently applied over a wide area, from one end to the other, on at least one of the ventral and dorsal sides. As a result, even if the return stress in the width direction of the waist area is low, surface tension can suppress the absorbent article from slipping down from the wearer's waist. At the same time, it can suppress the occurrence of skin problems caused by skin compression over a wide area of ​​the waist area.

[0028] [Aspect 8] The absorbent article according to any one of embodiments 1 to 7, wherein the anti-slip agent is applied to the ends of the absorbent in the longitudinal and / or width directions so as to overlap in the thickness direction.

[0029] In the longitudinal and / or widthwise directions, the ends of the absorbent material are highly rigid, while the parts outside the ends are less rigid. Due to this difference in rigidity, the ends of the absorbent material are prone to causing pressure on the skin of the waist. Therefore, in this absorbent material, an anti-slip agent is applied to the highly rigid ends of the absorbent material in the longitudinal and / or widthwise directions. This suppresses the occurrence of skin problems caused by pressure on the skin of the waist from the ends of the absorbent material. At the same time, slippage can be suppressed by surface tension instead of friction.

[0030] [Aspect 9] The absorbent article according to any one of embodiments 1 to 3, wherein the anti-slip agent is not applied to the outer end in the longitudinal direction of at least one of the ventral and dorsal portions.

[0031] When clothing comes into contact with the anti-slip agent, the fibers of the clothing can be adsorbed by the agent, and if these adsorbed fibers accumulate, they may have adverse effects on the skin. In addition, the adsorbed fibers may look like dirt, and consequently, the absorbent material may appear unsanitary. Therefore, in this absorbent material, the anti-slip agent is not applied to the outer longitudinal edge of at least one of the ventral and dorsal sides. Thus, it is possible to prevent clothing fibers from adsorbing to the outer longitudinal edges of the ventral and dorsal sides, which are prone to contact with the wearer's clothing. This reduces adverse effects on the skin caused by adsorbed fibers and prevents the absorbent material from appearing unsanitary.

[0032] [Aspect 10] The absorbent article according to any one of embodiments 1 to 9, wherein the anti-slip agent is not applied to the inner end in the longitudinal direction of at least one of the ventral and dorsal portions.

[0033] When clothing or the floor surface comes into contact with the anti-slip agent, the fibers of the clothing and dust from the floor surface can be adsorbed by the agent. If these adsorbed fibers and dust accumulate, they may have adverse effects on the skin. In addition, the adsorbed fibers and dust may look like dirt, and consequently, the absorbent material may become unsanitary. Therefore, in this absorbent material, the anti-slip agent is not applied to the inner longitudinal edge of at least one of the ventral and dorsal sides. Thus, it is possible to prevent the fibers of clothing and dust from adsorbing to the inner longitudinal edge of the ventral and dorsal sides, which are prone to contact with the wearer's clothing and the floor surface. This ensures that adverse effects on the skin from adsorbed fibers and dust are avoided and that the absorbent material remains clean.

[0034] [Aspect 11] The absorbent article according to any one of embodiments 1 to 10, wherein the anti-slip agent is applied to both outer sides in the width direction of the absorbent body, beyond both ends in the width direction, on at least one of the ventral and dorsal portions of the absorbent body.

[0035] The portions on the ventral and dorsal sides of the absorbent body that are wider than the ends in the width direction do not overlap with the absorbent body and have low rigidity, making them areas where the elastic force of multiple elastic members is easily effective. Therefore, in this absorbent article, an anti-slip agent is applied to these areas where the elastic force is easily effective, i.e., the portions on both the ventral and dorsal sides that are wider than the ends in the width direction of the absorbent body, in at least one of the ventral and dorsal sides. This synergistically provides the effect of ensuring a good fit between the ventral and dorsal sides and, consequently, the absorbent article, to the wearer's waist by the multiple elastic members, as well as the effect of preventing slippage by the anti-slip agent.

[0036] [Aspect 12] The absorbent article according to any one of embodiments 1 to 11, wherein the anti-slip agent is applied between the longitudinal end and the longitudinal outer end of the absorbent body on at least one of the ventral and dorsal portions.

[0037] In this absorbent article, an anti-slip agent is applied between the longitudinal end and the longitudinal outer end of the absorbent body on at least one of the ventral and dorsal sides. This anti-slip agent supports the absorbent body, which becomes heavier after absorbing excreted urine. As a result, even though the return stress in the width direction of the combined ventral and dorsal sides is low, the absorbent article can be more reliably prevented from slipping down from the wearer's waist.

[0038] [Aspect 13] The absorbent article according to any one of embodiments 1 to 12, wherein each of the ventral and dorsal portions is located on the skin side, and includes an inner sheet whose skin-side surface constitutes the skin-contacting surface, the inner sheet includes hydrophobic fibers, the anti-slip agent is a hydrophilic agent, and the anti-slip agent is positioned where the hydrophobic fibers are present in the inner sheet.

[0039] In this absorbent article, the inner sheet in at least one of the ventral and dorsal sides contains hydrophobic fibers, and a hydrophilic anti-slip agent is applied where the hydrophobic fibers are present. By applying the hydrophilic anti-slip agent where the hydrophobic fibers are present in the inner sheet in this way, it is possible to make it difficult for the anti-slip agent to penetrate the inner sheet. As a result, the effects of the anti-slip agent applied to the inner sheet, such as the effect of reducing friction and the effect of suppressing slippage, can be exerted more effectively, and the effect of the anti-slip agent can be produced even with a small amount, and the effect can be easily sustained.

[0040] Hereinafter, an absorbent article according to an embodiment of the present invention will be described with reference to the drawings, using a disposable diaper for children as an example. However, the present invention is not limited to its embodiments and examples, and can be applied to other types of absorbent articles, such as disposable diapers for children with different details, disposable diapers for adults, and sanitary napkins in the form of panties, without departing from the subject matter of the present invention.

[0041] The disposable diaper 1 of this embodiment is of the pant type. Figures 1 to 3 show the disposable diaper 1 according to this embodiment. Figure 1 is a plan view showing the unfolded state of an example of the configuration of the disposable diaper 1, and therefore shows the state in which the elastic member is extended and the side seal portion (described later) is not joined. Figure 2 is a cross-sectional view along the longitudinal center line CL (described later) in Figure 1. Figure 3 is a cross-sectional view along the widthwise center line CW (described later) in Figure 1.

[0042] Disposable diaper 1, in the unfolded state shown in Figures 1 to 3, has a longitudinal direction L, a width direction W, and a thickness direction T that are mutually orthogonal. The imaginary line passing through the center of the width direction W of disposable diaper 1 and extending along the longitudinal direction L is called the longitudinal centerline CL, and the width centerline passing through the center of the longitudinal direction L and extending along the width direction W is called the width centerline CW. Here, the direction and side approaching the longitudinal centerline CL are considered the inward and inward directions of the width direction W, respectively, and the direction and side moving away from the width centerline CL are considered the outward and outward directions of the width direction W, respectively. On the other hand, the direction and side approaching the width centerline CW are considered the inward and inward directions of the longitudinal direction L, respectively, and the direction and side moving away from the width centerline CW are considered the outward and outward directions of the longitudinal direction L, respectively. Furthermore, viewing disposable diaper 1 placed on a plane parallel to the plane containing the longitudinal direction L and the width direction W from above the plane in the thickness direction T is called a "planar view," and the shape perceived in a planar view is called the "planar shape." Any direction within a plane including the longitudinal direction L and the width direction W is called the "plane direction". When disposable diaper 1 is worn, the side of the disposable diaper 1 that is relatively closer to the wearer's skin and the side that is farther away from the wearer's skin in the thickness direction T are also called the "skin side" and the "non-skin side", respectively. In disposable diaper 1, the surface that comes into contact with the skin and the surface opposite it are also called the "skin-contact surface" and the "non-skin-contact surface", respectively. In the longitudinal direction L, the side that is relatively closer to the ventral side (described later) or farther away from the dorsal side (described later) is also called the ventral side or anterior side, and the side that is relatively closer to the dorsal side or farther away from the ventral side is also called the dorsal side or posterior side. The above definitions are also applied to each material of disposable diaper 1 and to disposable diaper 1 when it is worn.

[0043] In the case of disposable diapers 1, the statement that their components, structure, and shape are aligned with a predetermined direction (for example, the longitudinal direction L, the width direction W, and the thickness direction T) includes not only cases where the components are parallel to the predetermined direction, but also cases where they are within a range of ±30° with respect to the predetermined direction. For curved or curved components, the components are evaluated as described above with respect to the tangents at each point on the curve.

[0044] The disposable diaper 1 comprises an abdominal portion 3, a dorsal portion 2, and an absorbent body 4. The abdominal portion 3 is the part of the disposable diaper 1 that covers the wearer's abdomen. The absorbent body 4 is the part of the disposable diaper 1 that covers the wearer's groin area and includes an absorbent material 8. The dorsal portion 2 is the part of the disposable diaper 1 that covers the wearer's back. At least the front and rear ends of the absorbent body 4 in the longitudinal direction L extend to the central portion in the width direction W of the abdominal portion 3 and dorsal portion 2, respectively.

[0045] In this embodiment, the front and rear ends of the absorbent body 4 are connected, for example, to the central portion in the width direction W of the ventral portion 3 and the dorsal portion 2, respectively, by an adhesive (example: hot melt adhesive, the same applies hereinafter). In this case, the front and rear ends of the absorbent body 4 reach approximately the central portion in the longitudinal direction L of the ventral portion 3 and the dorsal portion 2, respectively, but may also reach approximately the outer ends in the longitudinal direction L.

[0046] Disposable diaper 1 is formed by joining together a pair of ventral joints 3a located at both ends of the width direction W of the ventral portion 3 and extending along the longitudinal direction L, and a pair of dorsal joints 2a located at both ends of the width direction W of the dorsal portion 2 and extending along the longitudinal direction L. The pair of ventral joints 3a and the pair of dorsal joints 2a joined together are also called a pair of side seals. In this case, in disposable diaper 1, the ventral portion 3 and dorsal portion 2 joined together by the pair of side seals form a waist area that covers the wearer's waist. In addition, the outer ends of the ventral portion 3 and dorsal portion 2 in the longitudinal direction L define a waist opening through which the wearer's waist passes. Furthermore, in disposable diaper 1, the ends on both sides of the width direction W of the absorbent body 4 and the inner ends of the ventral portion 3 and dorsal portion 2 in the longitudinal direction L define a pair of leg openings through which the wearer's legs pass.

[0047] In this embodiment, when unfolded, the ventral portion 3 and the dorsal portion 2 each have a rectangular shape that is generally long in the width direction W, and are spaced apart from each other in the longitudinal direction L. The absorbent body 4 has a rectangular shape that is generally long in the longitudinal direction L, and one end in the longitudinal direction L is connected to the ventral portion 3, and the other end is connected to the dorsal portion 2. The ventral portion 3, the absorbent body 4, and the dorsal portion 2 are formed separately from each other. Therefore, the disposable diaper 1 is a 3-piece type. At least two of the ventral portion 3, the absorbent body 4, and the dorsal portion 2 may be formed as a single unit, or they may be connected as a single unit by another outer sheet or the like. For example, if the ventral portion 3 and the dorsal portion 2 share at least one of the sheet members that make up the ventral portion 3 and the dorsal portion 2, and are formed as a single unit by a continuous sheet member, then the disposable diaper 1 can be said to be a 2-piece type composed of that and the absorbent body 4. A two-piece disposable diaper is a disposable diaper that, when unfolded, has an abdominal section, a crotch section, and a dorsal section, with the abdominal, crotch, and dorsal sections joined together by a single outer covering.

[0048] Each of the ventral portion 3 and the dorsal portion 2 is formed from a liquid-impermeable sheet material. In this embodiment, each of the ventral portion 3 and the dorsal portion 2 has at least the skin-facing surface (inner sheet material 31, 21: described later) made from a sheet material containing hydrophobic fibers. Therefore, at least the surface portion of the skin-facing side of the sheet material contains hydrophobic fibers. As a result, hydrophilic agents have difficulty penetrating the surface portion of the skin-facing side. However, each of the ventral portion 3 and the dorsal portion 2 may also have the non-skin-facing side (outer sheet material 32, 22: described later) made from a sheet material containing hydrophobic fibers. The surface portion refers to the area from the surface of the sheet material up to 1 / 4 of its thickness.

[0049] When a sheet material contains hydrophobic fibers, it is preferable that the fibers constituting the sheet material contain 70% by mass or more of hydrophobic fibers, more preferably 80% by mass or more, even more preferably 90% by mass or more, and may even be 100% by mass. Examples of hydrophobic fibers include thermoplastic resin fibers, such as polyolefin resin fibers like polypropylene and polyethylene, polyamide resin fibers like 6-nylon and 6,6-nylon, and polyester resin fibers like polyethylene terephthalate and polybutylene terephthalate. It is preferable that these thermoplastic fibers do not contain hydrophilic agents. A sheet material containing 70% by mass or more of hydrophobic fibers can be called a hydrophobic sheet material (hydrophobic sheet).

[0050] The ventral portion 3 is formed by laminating an inner sheet member 31 located on the skin side and an outer sheet member 32 located on the non-skin side in the thickness direction T, and joining them with an adhesive or heat seal (the same applies hereinafter). Similarly, the dorsal portion 2 is formed by laminating an inner sheet member 21 located on the skin side and an outer sheet member 22 located on the non-skin side in the thickness direction T, and joining them with an adhesive or the like.

[0051] In this embodiment, the outer sheet member 32 on the non-skin side has its outer end in the longitudinal direction L folded back towards the skin side and overlapping the inner sheet member 31 on the skin side. In this case, the outer sheet member 32 that has been folded back and is located on the skin side is considered to be the inner sheet member 31. Similarly, the outer sheet member 22 on the non-skin side has its outer end in the longitudinal direction L folded back towards the skin side and overlapping the inner sheet member 21 on the skin side. In this case, the outer sheet member 22 that has been folded back and is located on the skin side is considered to be the inner sheet member 21.

[0052] In this embodiment, the ventral portion 3 and the dorsal portion 2 are joined at multiple locations by an inner sheet member 31, 21 and an outer sheet member 32, 22, respectively, using a hydrophobic adhesive. Therefore, in each of the ventral portion 3 and the dorsal portion 2, adhesive is scattered at multiple locations on the inner sheet member 31, 21 and the outer sheet member 32, 22, respectively.

[0053] In the ventral portion 3, multiple waist elastic members 13 for waist gathering are arranged between the inner sheet member 31 located on the skin side and the outer sheet member 32 located on the non-skin side. The multiple waist elastic members 13 extend along the width direction W from one end of the ventral portion 3 in the width direction W to the other, except for the area that overlaps with the central part of the absorber 8 in the thickness direction T, and are arranged with gaps in the longitudinal direction L. The inner sheet member 31 and the outer sheet member 32 and the multiple waist elastic members 13 are joined together with an adhesive or the like. In this embodiment, a hydrophobic adhesive is used.

[0054] In the back portion 2, multiple waist elastic members 12 for waist gathering are arranged between the inner sheet member 21 located on the skin side and the outer sheet member 22 located on the non-skin side. The multiple waist elastic members 12 extend along the width direction W from one end of the back portion 2 in the width direction W to the other, except for the area that overlaps with the central part of the absorber 8 in the thickness direction T, and are arranged with gaps in the longitudinal direction L. The inner sheet member 21 and the outer sheet member 22 and the multiple waist elastic members 12 are joined together with an adhesive or the like. In this embodiment, a hydrophobic adhesive is used.

[0055] In this embodiment, the ventral portion 3 may include a ventral cover sheet member 43 positioned on the skin-facing surface so as to cover the ventral end of the absorbent body 4 in the longitudinal direction L from the skin side. The ventral cover sheet member 43 prevents the ventral end of the absorbent body 4 from directly touching the wearer's skin, thereby suppressing skin friction. Similarly, the dorsal portion 2 may include a dorsal cover sheet member 42 positioned on the skin-facing surface so as to cover the dorsal end of the absorbent body 4 in the longitudinal direction L from the skin side. The dorsal cover sheet member 42 prevents the dorsal end of the absorbent body 4 from directly touching the wearer's skin, thereby suppressing skin friction. The ventral cover sheet member 43 and the dorsal cover sheet member 42 are made of the same material as the inner sheet members 31 and 21, for example.

[0056] Multiple waist elastic members 12 and 13 expand and contract the waist area. There are no particular restrictions on the type of elastic member, but examples include thread-like or sheet-like rubber. There are no particular restrictions on the material of each elastic member, but examples include styrene-butadiene rubber and urethane rubber. The characteristics of each elastic member, such as the size of the cross-section (wire diameter, etc.) and the elongation ratio, are appropriately selected according to the magnitude of the tightening force corresponding to the position within the waist WP.

[0057] Examples of the sheet materials mentioned above include any liquid-impermeable sheet, such as liquid-impermeable nonwoven fabrics, synthetic resin films, composite sheets thereof, SB nonwoven fabrics, SMS nonwoven fabrics, etc. There are no particular restrictions on the type of nonwoven fabric, such as meltblown nonwoven fabrics, spunbond nonwoven fabrics, airlaid nonwoven fabrics, and air-through nonwoven fabrics. There are no particular restrictions on the material of the nonwoven fabric or synthetic resin film of the sheet material, as long as it can be used for sanitary products, but examples include polyolefin resins such as polypropylene and polyethylene, polyamide resins such as 6-nylon and 6,6-nylon, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate. The basis weight of the nonwoven fabric of the sheet material is, for example, 5 to 100 g / m². 2 The amount is preferably 10-50 g / m². 2The length (thickness) of the sheet member in the thickness direction T is, for example, 0.1 to 5 mm, preferably 0.1 to 2 mm. The sheet members constituting the ventral portion 3 and the dorsal portion 2 may be two sheets, the inner sheet member and the outer sheet member, one sheet, or three or more sheets (not shown). The sheet members do not need to be folded (not shown). If each sheet member is a hydrophobic sheet, for example, if the sheet member contains hydrophobic fibers as the main constituent fibers, then a hydrophobic material can be selected from the above materials as the material for the fibers constituting the sheet member.

[0058] In this embodiment, the disposable diaper 1 further comprises an outer sheet member 14 that bridges the gap between the ventral portion 3 and the dorsal portion 2. The outer sheet member 14 is a liquid-impermeable sheet member, such as a nonwoven fabric, and its ends in the longitudinal direction L are laminated to the ventral portion 3 and the dorsal portion 2, respectively, and joined with an adhesive or the like. The type and material of the nonwoven fabric are as described above. The outer sheet member 14 is also joined with an adhesive or the like to the non-skin side of the absorbent body 4, which is generally positioned between the ventral portion 3 and the dorsal portion 2, thereby assisting and protecting the absorbent body 4 from the non-skin side. The outer sheet member 14 may be composed of two or more sheet members (not shown). Another sheet member separate from the outer sheet member 14 may be provided on the non-skin side (not shown).

[0059] The disposable diaper 1 may further include a sheet-like stretchable member (not shown) that is attached with adhesive to the non-skin side (or skin side) of at least one of the ventral portion 3 and the dorsal portion 2, and that extends along the width direction W and stretches in the width direction W. The sheet-like stretchable member is, for example, a sheet-like member that is stretchable in the width direction W, and functions as a waist gather and / or sweat-absorbing sheet. Examples of the types of sheet-like stretchable members include stretchable nonwoven fabrics that are composites of styrene rubber, olefin rubber, urethane rubber, etc., with nonwoven fabric or paper, etc.

[0060] The absorbent body 4 is located in the center of the width direction W and has a central body portion 10 that extends along the longitudinal direction L, and may further have a pair of leg gather portions 5 located at both ends of the width direction W and extending along the longitudinal direction L. Each of the pair of leg gather portions 5 extends along the longitudinal direction L and has a plurality of leg elastic members 5a that are spaced apart in the width direction W.

[0061] The central part 10 of the main body has a roughly rectangular shape and includes a liquid-permeable surface sheet 7, a liquid-impermeable back sheet 9, and an absorbent 8 located between the surface sheet 7 and the back sheet 9 that absorbs and retains liquid. The absorbent 8 is joined to the surface sheet 7 and the back sheet 9 by adhesive, and the surface sheet 7 and the back sheet 9 are joined to each other by adhesive at their peripheral edges. The shape of the central part 10 of the main body is not limited to the above example, as long as it is long in the longitudinal direction L, for example, a rectangle with rounded corners, a rectangle with a short side that curves outward, or an hourglass shape.

[0062] Examples of surface sheets 7 include liquid-permeable nonwoven or woven fabrics, synthetic resin films with liquid-permeable pores, and composite sheets thereof. Examples of backing sheets 9 include liquid-impermeable nonwoven fabrics or synthetic resin films, composite sheets thereof, and SMS nonwoven fabrics. There are no particular restrictions on the type of nonwoven fabric, and examples include meltblown nonwoven fabrics, spunbond nonwoven fabrics, airlaid nonwoven fabrics, and air-through nonwoven fabrics. There are no particular restrictions on the type of synthetic resin film, and known film materials can be used. There are no particular restrictions on the materials of the nonwoven fabrics and synthetic resin films as long as they can be used for sanitary products, but examples include olefin resins such as polyethylene and polypropylene, polyamide resins such as 6-nylon and 6,6-nylon, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate. Cellulose fibers may be used as the material for the nonwoven fabric. To provide breathability, the synthetic resin film may contain inorganic particles such as calcium carbonate.

[0063] The absorber 8 includes an absorption core 8b that absorbs and holds liquid, and a core wrap 8a that encloses the absorption core 8b, and may include a groove portion 8c that can diffuse the liquid in the longitudinal direction L and the width direction W. As the material of the absorption core 8b, at least one of an absorber material, for example, a cellulose-based fiber and a superabsorbent polymer, can be mentioned. Examples of the cellulose-based fiber include natural cellulose fibers such as pulp fibers such as wood pulp fibers, crosslinked pulp fibers, and non-wood pulp fibers, regenerated cellulose fibers, and semi-synthetic cellulose fibers. In the case of pulp fibers, as the size thereof, the average major diameter of the fibers is, for example, several tens of μm, preferably 20 to 40 μm, and the average fiber length is, for example, several mm, preferably 2 to 5 mm. Examples of the superabsorbent polymer (Super Absorbent Polymer: SAP) include polyacrylate-based, polysulfonate-based, and maleate anhydride-based water-absorbent polymers. As the size (when dry) of the superabsorbent polymer, the average particle diameter is, for example, several hundreds of μm, preferably 200 to 500 μm. As the basis weight of the cellulose-based fiber and the superabsorbent polymer, for example, 100 to 400 g / m 2 can be mentioned. Examples of the material of the core wrap 8a include liquid-permeable sheets such as non-woven fabrics and tissues.

[0064] The central part 10 of the main body is provided with a pair of leak-proof walls 6 arranged facing each other on both sides in the width direction W and extending along the longitudinal direction L. Each leak-proof wall 6 is formed of a leak-proof sheet member 6b that extends along the longitudinal direction L and contains a plurality of leak-proof elastic members 6a arranged at intervals in the width direction W. The outer end of each leak-proof wall 6 in the width direction W is joined to at least one of the surface sheet 7, absorbent 8, and back sheet 9 with an adhesive or the like to form a fixed end, and the inner end in the width direction W is spaced apart from the other sheets, including the surface sheet 7, to form a free end. The plurality of leak-proof elastic members 6a are joined with an adhesive near the free end of the leak-proof sheet member 6b. Examples of leak-proof sheet members 6b include hydrophobic sheet members, and examples of hydrophobic sheet members include nonwoven fabrics containing hydrophobic fibers. The type and material of the nonwoven fabric are the same as, for example, as in the case of the inner sheet members 31 and 21 described above. Multiple leak-proof elastic members 6a are exemplified by rubber threads, but the type and material of the elastic members are as described above. The characteristics of the elastic members, such as the size of the cross-section (wire diameter, etc.) and the elongation ratio, are appropriately selected according to the function of the leak-proof wall 6. Note that each leak-proof wall 6 may have its inner end in the width direction W folded back to the outside in the width direction W.

[0065] A pair of leg gather sections 5 are joined to both ends of the main body central section 10 in the width direction W. Each leg gather section 5 extends along the longitudinal direction L and comprises a plurality of leg elastic members 5a arranged at intervals in the width direction W, and a skin-side and a non-skin-side leg sheet member 5b that sandwiches the plurality of leg elastic members 5a. The inner end of each leg gather section 5 in the width direction W is joined to the non-skin-side surface of the end of the main body central section 10 in the width direction W with adhesive to form a fixed end, and the outer end in the width direction W is spaced apart from the main body central section 10 to form a free end. The plurality of leg elastic members 5a are joined with adhesive near the free ends of the skin-side and non-skin-side leg sheet members 5b. The plurality of leg elastic members 5a cause each leg gather section 5 to expand and contract. Examples of leg sheet members 5b include hydrophobic sheet members, and examples of hydrophobic sheet members include nonwoven fabrics containing hydrophobic fibers. The type and material of the nonwoven fabric are as described above. The multiple leg elastic members 5a are exemplified by elastic threads, and the type and material of these elastic members are as described above. The characteristics of the elastic members, such as the size of the cross-section (linearity, etc.) and the elongation ratio of the elastic members, are appropriately selected according to the magnitude of the tightening force corresponding to the position within the leg gather portion 5.

[0066] In the disposable diaper 1, a pair of leg gathers 5 are bridged by an outer sheet member 14. The outer sheet member 14 is laminated at both ends in the width direction W to the inner ends in the width direction W of each of the pair of leg gathers 5 and joined with an adhesive or the like, thus supporting and protecting the pair of leg gathers 5 from the non-skin side. The pair of leg gathers 5 may be formed integrally with the outer sheet member 14.

[0067] The dorsal portion 2 may include a dorsal extension that extends further inward from the inner edge in the longitudinal direction L of the dorsal main body portion, which occupies substantially the same area as the dorsal joint portion 2a in the longitudinal direction L. The dorsal extension is the inner region of the dorsal portion 2 in the longitudinal direction L. The portion of the dorsal extension that does not overlap with the absorbent main body 4, i.e., the portions on both sides in the width direction W, functions as a pair of buttock cover portions 40. The buttock cover portions 40 protect the wearer's buttocks from the outside. The buttock cover portions 40 include a buttock elastic member 41 that deforms the buttock cover portions 40 to conform to the wearer's buttocks.

[0068] Next, the disposable diaper 1 (absorbent article) in this embodiment will be described in more detail. In this disposable diaper 1 (absorbent article), the waist portion, which is composed of the ventral portion 3 and the dorsal portion 2, includes an elastic member that expands and contracts in the width direction W. At that time, the return stress in the width direction W of the waist portion is 0.010 N / mm to 0.030 N / mm or less. Furthermore, an anti-slip agent is applied to the skin-contact surfaces of the waist portion, which are composed of the skin-contact surface 3S of the ventral portion 3 and the skin-contact surface 2S of the dorsal portion 2.

[0069] As described above, this disposable diaper 1 includes, for example, a plurality of waist elastic members 13 in the ventral portion 3 and a plurality of waist elastic members 12 in the dorsal portion 2, as elastic members that stretch in the width direction W. These waist elastic members contribute to improving the fit of the disposable diaper 1 and preventing it from slipping down.

[0070] Here, the return stress is the stress when both ends in the width direction W of the waist portion (where the ventral portion 3 and the dorsal portion 2 are joined) of the disposable diaper 1 are pulled outwards in the width direction W, and is one indicator of the magnitude of the force with which the waist portion constricts the wearer's waist. If the return stress is large, it can be said that the waist portion constricts the wearer's waist with a large force. The return stress of this disposable diaper 1 is set to a low value of 0.010 N / mm to 0.030 N / mm or less. Therefore, the constricting force of the disposable diaper 1 is reduced to suppress compression of the wearer's waist skin. However, the method for measuring the return stress will be described later.

[0071] The disposable diaper 1 has an anti-slip agent applied to the skin-contact surfaces of the waist area, which consist of the skin-contact surface 3S of the ventral portion 3 and the skin-contact surface 2S of the dorsal portion 2. The anti-slip agent is an agent that prevents the disposable diaper 1 from slipping down. Figure 4 is a plan view of the unfolded state showing an example of application of the anti-slip agent SC in the disposable diaper 1 according to the embodiment of Figure 1. However, the areas indicated by multiple dots are areas to which the anti-slip agent SC has been applied (the same applies to Figures 5 to 7 below). In this embodiment, the anti-slip agent SC is applied (placed) on both the skin-contact surfaces 3S and 2S (skin-facing surfaces) of the ventral portion 3 and the dorsal portion 2. The areas in the ventral portion 3 and the dorsal portion 2 where the anti-slip agent SC is applied / placed can be called the areas 3EA and 2EA where the anti-slip agent SC exists. Note that in Figure 4, the anti-slip agent SC may be applied to only one of the ventral portion 3 and the dorsal portion 2.

[0072] It is preferable that the shear prevention agent SC be applied to the member facing the skin. Therefore, when the shear prevention agent SC is applied to the ventral portion 3, it is applied to at least the inner sheet member 31 of the ventral portion 3, and if a ventral cover sheet member 43 is provided, it is also applied to the ventral cover sheet member 43. Similarly, when the shear prevention agent SC is applied to the dorsal portion 2, it is applied to at least the inner sheet member 21 of the dorsal portion 2, and if a dorsal cover sheet member 42 is provided, it is also applied to the dorsal cover sheet member 42.

[0073] However, the areas where the anti-slip agent SC exists in each sheet member (e.g., areas 3EA, 2EA) do not need to cover the entire surface of the skin-contacting surface of each sheet member (e.g., skin-contacting surfaces 3S, 2S). The areas where the anti-slip agent SC exists are, for example, at least 20% of the skin-contacting surface of the sheet member in terms of area ratio, preferably 40% or more, more preferably 60% or more, and even more preferably 80% or more. Furthermore, the anti-slip agent SC does not need to be present in only one sheet member; it may be present in multiple sheet members. The anti-slip agent SC may be present continuously or intermittently in a single sheet member. Intermittent means, for example, in a stripe pattern, checkerboard pattern, or grid pattern. The anti-slip agent SC may be present in multiple locations independently of each other in a single sheet member.

[0074] In this disposable diaper 1 (absorbent material), the waist portion (joined from the ventral portion 3 and the dorsal portion 2) includes elastic members (waist elastic members 13, 12) that expand and contract in the width direction W. This ensures a good fit of the waist portion, and consequently the disposable diaper 1, to the wearer's waist. At that time, since the return stress in the width direction W of the waist portion is low (0.010 N / mm or more, 0.030 N / mm or less), it is possible to suppress pressure and chafing on the wearer's waist skin caused by the materials constituting the skin contact surfaces 3S, 2S of the waist portion, including the elastic members. Furthermore, since an anti-slip agent SC is applied to the skin contact surface of the waist portion, that is, the anti-slip agent SC is interposed between the materials of the waist portion and the skin, chafing between the materials and the skin can be suppressed. As a result, skin problems for the wearer can be suppressed. Furthermore, the presence of the anti-slip agent SC between the waist area and the skin prevents the disposable diaper 1 from slipping down the wearer's waist even if the return stress in the width direction of the waist area is low. Therefore, the disposable diaper 1 can improve fit and prevent slipping while also suppressing skin problems for the wearer. (Note that a return stress of 0.010 N / mm or higher suppresses slipping through a synergistic effect with the anti-slip agent, and a return stress of 0.030 N / mm or lower suppresses the occurrence of skin problems caused by skin compression.)

[0075] <Method for measuring return stress> Figure 8 is a schematic diagram illustrating the method for measuring return stress. However, the longitudinal direction L and width direction W of the disposable diaper being measured are the same as those in Figure 4. (1) Prepare a disposable diaper (pants type) as sample Sa. Furthermore, prepare fixing jigs 91 for pulling both ends in the width direction W of the waist portion BR (where the ventral portion 3 and the dorsal portion 2 are joined) of sample Sa outwards in the width direction W. However, two fixing jigs 91 are prepared, one for one end in the width direction W of the waist portion BR of sample Sa and one for the other end. Each fixing jig 91 has a rod-shaped portion 91a that is longer than the length L in the longitudinal direction of the side seal portion Ss (where the ventral joint portion 3a and the dorsal joint portion 2a are joined) of sample Sa. (2) Attach two fixing jigs 91 to the autograph (manufactured by Shimadzu Corporation, model number AG-XPlus HS). (3) Attach the sample Sa to the two fixing jigs 91 (in the direction of the white arrows in Figure 8). At that time, attach the sample Sa to the fixing jig 91 such that the width direction W of the body portion BR of the sample Sa is parallel to the tension direction DE of the Autograph's tensioning machine, and that the extension line EL, which passes through the tensioning part of the Autograph's tensioning machine and is parallel to the tension direction DE, coincides with the center of the longitudinal direction L of the side seal portion Ss of the sample. For this attachment, the rod-shaped portion 91a of the fixing jig 91 for one end is inserted into the inside of the body portion BR near one end of the width direction W of the body portion BR (for example, the upper end in Figure 8) so as to be parallel to the side seal portion Ss. The rod-shaped portion 91a of the fixing jig 91 for the other end is inserted into the inside of the body portion BR near the other end of the width direction W of the body portion BR (for example, the lower end in Figure 8) so as to be parallel to the side seal portion Ss. (4) Adjust the distance Dc between the chucks of the Autograph (manufactured by Shimadzu Corporation) (distance inside the fixing jig 91) to set the length Dx in the width direction W inside the body circumference BR (distance between the side seals Ss) to 50% of the length Dx when extended (hereinafter this length is also called the "circumference"). (5) The sample Sa is fixed to the fixing jig 91, and the fixing jig 91 is moved at a chuck speed of 100 mm / min (in the direction of the black arrow in Figure 8) to stretch the waist circumference BR until the length Dx is 90% of the circumference. Then, the direction of movement is reversed from that position, and the fixing jig 91 is returned to its original position at the same speed. That is, the length Dx is returned to 50% of the circumference. This operation is repeated twice, and on the second time, the stress value at the point when the length Dx is 2 / 3 of the circumference is recorded. The value of the stress per unit length is calculated by dividing this value by the length L in the longitudinal direction of the waist circumference BR (measured at the position of the side seal), and this is called the return stress. The reason why the return stress is taken as the stress at this length of 2 / 3 of the circumference is that this length is the average waist circumference length of a disposable diaper when worn.

[0076] The anti-slip agent SC is not particularly limited as long as it can prevent the disposable diaper 1 from slipping down from the wearer's waist, but it is preferable that it has a moisturizing effect. In this embodiment, the anti-slip agent is described as a hydrophilic moisturizer as an example, but a hydrophobic (oil-based) moisturizer may also be used. The hydrophilic moisturizer preferably contains moisturizing components and water, and the main component of the hydrophilic moisturizing component is preferably a component that can form hydrogen bonds with the water on the skin surface and create surface tension between the skin and the skin, such as glycerin, hyaluronic acid, urea, and heparin-like substances, and glycerin, which is a hygroscopic moisturizer, is particularly preferred. Examples of oil-based moisturizers include ceramide and petrolatum, which suppress water evaporation from the skin. As an auxiliary to the moisturizing component, for example, a polyhydric alcohol having moisturizing and antibacterial (preservative) properties may be further included. Examples of polyhydric alcohols include butylene glycol, propylene glycol, dipropylene glycol, and propanediol. Furthermore, as an additive to the moisturizing component, it may further contain an agent having pharmacological effects such as anti-inflammatory or detoxification effects. An auxiliary agent having antibacterial (preservative) effects can also be called a preservative (antibacterial) auxiliary agent. In this embodiment, the anti-slip agent includes, for example, glycerin, water, and an auxiliary agent.

[0077] The anti-slip agent SC preferably contains 45% by mass or more of a hygroscopic humectant under conditions of 20°C and 60% RH relative humidity. By containing 45% by mass or more of a hygroscopic humectant, hydrogen bonds are formed between the hygroscopic humectant and the moisture on the skin surface, creating surface tension between the anti-slip agent SC on at least one of the ventral portion 3 and the dorsal portion 2 and the wearer's waist. As a result, even if the return stress in the width direction W of the waist portion is low, the disposable diaper 1 can be more effectively prevented from slipping down from the wearer's waist. In addition to this effect of preventing slippage, the presence of the hygroscopic humectant between the waist portion material and the skin of the waist can suppress skin problems caused by skin compression.

[0078] The hygroscopic moisturizer contained in the above-mentioned anti-slip agent SC preferably contains glycerin. This allows the hygroscopic moisturizer to exert its effect more reliably. In other words, since slippage can be suppressed by surface tension, even if the return stress in the width direction of the waist area is low, the absorbent material can be more effectively prevented from slipping off the wearer's waist. At the same time, because glycerin is interposed between the waist area material and the skin of the waist, the occurrence of skin problems caused by skin compression can be suppressed, thus preventing skin problems for the wearer.

[0079] In the above-mentioned anti-slip agent, there are no particular restrictions on the proportion of each component as long as an anti-slip effect is achieved. For example, under conditions of a temperature of 20°C and a relative humidity of 60%RH, the main component of the moisturizing agent is 40-80% by mass, and the other components, including auxiliary agents, water, and additives, are 60-20% by mass.

[0080] If the anti-slip agent is a humectant, the method for measuring whether the humectant is hydrophilic or hydrophobic, and the method for measuring the component ratio are as follows. <Methods for measuring the hydrophilicity and hydrophobicity of humectants and methods for measuring component ratios> (1) Cut out a portion of the nonwoven fabric coated with moisturizer from the disposable diaper to a predetermined size (for example, 5cm x 5cm). (2) Immerse the cut nonwoven fabric in a beaker containing a predetermined amount of water (for example, 500 ml) to dissolve the humectant in the water. (3) The water used for extraction is evaporated under heated and reduced pressure (evaporator) to concentrate the humectant components. If no extracted components are present after the water evaporates (nothing precipitates), the humectant is hydrophobic. (4) If the humectant is hydrophilic, (if the components have been extracted) leave the water in which the humectant has dissolved in a beaker to stand for 4 weeks at a temperature of 20°C and a relative humidity of 60%RH. (5) After the time has elapsed, the water in which the humectant has dissolved is analyzed using a liquid chromatography-mass spectrometer (LC-MS) to measure the mass of each component. (6) From the obtained components and their masses, calculate the ratio of each component (excluding water). If you also want to measure the moisture content, perform the following measurements separately from (1) to (6) above. (7) Separately, perform (1) and (2) above, and leave the water in which the humectant has dissolved in a beaker for a while at a temperature of 20°C and a relative humidity of 60%RH. The water will evaporate, and a mixture (humectant containing water) containing the amount of water that can be contained at a temperature of 20°C and a relative humidity of 60%RH will be formed. Measure the mass of this mixture, including the beaker. (8) Then, place the beaker containing the mixture into a drying oven to remove the moisture from the mixture, and measure the mass of the beaker again. This will give you the mass of the water. (9) Calculate the ratio of each component (including water) from the mass of each component obtained in (5) above and the mass of water obtained in (8) above. (10) If it is confirmed in (3) above that the humectant is hydrophobic, the extraction in (1) and (2) above is carried out by changing the organic solvent to any organic solvent, and various measurements are performed according to (4) to (9).

[0081] There are no particular restrictions on the basis weight of the anti-slip agent SC, as long as it can provide anti-slip effects, but 0.3g / m² is acceptable. 2 More than 2.5g / m 2The following is preferable: The basis weight of the anti-slip agent is equal to or greater than the lower limit (0.3 g / m2), which allows for more reliable surface tension to be generated between the waist area and the wearer's waist. The basis weight of the anti-slip agent is equal to or greater than the upper limit (2.5 g / m2). 2 By keeping the amount below the upper limit, the anti-slip agent will not become sticky when worn. Furthermore, by keeping the amount below the upper limit, it will prevent the lubrication effect from outweighing the anti-slip effect, which could actually cause the item to slip down. Therefore, the optimal amount of anti-slip agent can achieve both anti-slip effect and reduced stickiness.

[0082] If the anti-shrinkage agent is a humectant, the method for measuring the basis weight of the humectant is as follows: <Method for measuring the basis weight of moisturizers> (1) Cut a portion of the nonwoven fabric coated with moisturizer from a disposable diaper to a predetermined size (e.g., 5cm x 5cm) and measure its mass. (2) If the humectant is hydrophilic, immerse the cut nonwoven fabric in a beaker containing a predetermined amount of water (for example, 500 ml). (3) After immersing the nonwoven fabric in water, repeatedly poke and stir it irregularly with a glass rod for more than 5 minutes, then leave it undisturbed in water for 60 minutes. (4) After that, the moisture contained in the nonwoven fabric is thoroughly squeezed out, and it is dried in an oven at 50 degrees Celsius or higher for 24 hours or more, and its mass is measured. (5) Calculate the mass of the humectant applied to the nonwoven fabric from the difference between the mass of the nonwoven fabric after drying and the weight of the nonwoven fabric before immersion in water. Divide the mass of the humectant by the area of ​​the nonwoven fabric to obtain the basis weight of the humectant. (6) If the humectant is hydrophobic, immerse the nonwoven fabric cut in (2) in a beaker using a predetermined amount of any organic solvent. Then, carry out (3) to (5) in the same manner.

[0083] In a preferred embodiment of this design, the disposable diaper 1 exhibits a sliding tensile stress of 0.10 N / mm or more and 0.12 N / mm or less in a sliding tensile test. However, the sliding tensile stress is one indicator of the magnitude of the force required for the disposable diaper 1 to slide off the waist. A larger sliding tensile stress indicates that a larger force is required for the disposable diaper 1 to slide off the waist. The method for measuring the sliding tensile stress in a sliding tensile test will be described later.

[0084] Thus, in this disposable diaper 1, the sliding tensile stress is 0.10 N / mm or more, which prevents the disposable diaper 1, which has become heavy after absorbing excreted urine with the absorbent material 8, from slipping down from the wearer's waist. As a result, slippage can be more reliably suppressed despite the low return stress in the width direction W of the waist area. On the other hand, the sliding tensile stress is 0.12 N / mm or less, which suppresses the occurrence of skin problems caused by skin compression, thus more reliably suppressing the occurrence of skin problems.

[0085] In a preferred embodiment of this design, the disposable diaper 1 exhibits a sliding tensile stress in a sliding tensile test that is 1.05 times or more and 1.25 times or less than the sliding tensile stress when the anti-slip agent SC is not applied to the skin-contacting surfaces (3S and 2S) of the waist area (ventral side 3 and dorsal side 2).

[0086] Thus, in this disposable diaper 1, the sliding tensile stress is 1.05 times or more the sliding tensile stress when no anti-slip agent is applied, which prevents the disposable diaper 1, which has become heavy after absorbing excreted urine in the absorbent material 8, from slipping down from the wearer's waist. As a result, slippage can be more reliably suppressed despite the low return stress in the width direction W of the waist area. On the other hand, since the sliding tensile stress is 1.25 times or less the sliding tensile stress when no anti-slip agent is applied, the occurrence of skin problems due to skin compression can be suppressed, thus more reliably preventing skin problems.

[0087] <Method for measuring sliding tensile stress> Figure 9 is a schematic diagram illustrating the method for measuring sliding tensile stress. (1) Prepare a disposable diaper (pants type) as sample Sa. However, apply 1.0 g / m2 of glycerin as a shear prevention agent SC to the waist area BR of sample Sa (where the ventral part 3 and dorsal part 2 are joined) at the position shown in Figure 4. (2) Prepare a cylinder 92 having a diameter that matches the size of sample Sa. Wrap the circumference of cylinder 92 with artificial skin (Ideatex Japan Co., Ltd., PBZ13001 Black). For example, if the size of sample Sa is "S" and "L", the average waist circumference of the wearer is 405 mm and 467 mm, respectively. Therefore, prepare a cylinder 92 with a diameter that matches these (the diameter is estimated using the formula: average waist circumference ≈ diameter × π). (3) Take a 100mm piece of 50mm wide masking tape GT. Fold this in half and glue the 10mm portions on the folded edge side together to form the mounting portion for the digital force gauge (Nidec-Shimpo, FGP-20). On the other hand, attach each of the remaining 40mm portions on the opposite side of the folded edge to the center of the width W on the front and rear sides of the center of the longitudinal L portion (the folded portion in the product) of the absorbent body AB (crotch area) of sample Sa. Next, on the mounting portion of the attached masking tape GT for the digital force gauge, make a 1mm diameter opening HL using a general-purpose drill at a position 5mm from the folded edge toward sample Sa. (4) In order to reproduce the environment of the wearer's skin surface, pure water is applied to the artificial skin on the surface of cylinder 92 using an air spray (Airtex Co., Ltd., Airbrush Workset METEO) to a basis weight of 1.0 ± 0.2 g / cm2. Then, it is left to stand for 30 seconds. (5) Attach the sample Sa to the cylinder 92 wrapped with artificial skin (direction of the white arrow in Figure 9). At this time, attach the sample Sa so that the lower end BRa of the torso circumference BR coincides with the upper end 92a of the cylinder 92. (6) Roll the cylinder 92 with the sample Sa attached over a table twice on a table while applying a pressure of 5 kg or more so that the same pressure as when the sample Sa was attached is applied to the sample Sa. (7) Attach the hooking jig of the zero-set digital force gauge to the opening HL and pull at 20 mm / second for 10 seconds (direction of the black arrow in Figure 8). This will remove the sample Sa from the cylinder 92. (8) Of the measurements taken with the digital force gauge, the peak value is recorded and this value is taken as the sliding tensile stress.

[0088] In a preferred embodiment of this design, the shear prevention agent SC is applied to at least one of the ventral portion 3 and the dorsal portion 2 (skin contact surfaces 3S and 2S) on the outside in the width direction W of the absorbent body 4, beyond both ends in the width direction W. In the example shown in Figure 4, the shear prevention agent SC is applied (placed) on both skin contact surfaces 3S and 2S of the ventral portion 3 and the dorsal portion 2 on the outside in the width direction W of the absorbent body 4, beyond both ends in the width direction W.

[0089] In this disposable diaper 1, the skin-contact surfaces 3S and 2S of the ventral portion 3 and dorsal portion 2, respectively, have low rigidity in the portions on both sides of the width direction W beyond the ends of the absorbent body 4 in the width direction W, as these portions do not overlap with the absorbent body 4. Therefore, these portions are areas where the elastic force of multiple elastic members, such as the waist elastic members 13 and 12, is easily effective. Accordingly, as described above, the anti-slip agent SC is applied to these portions where the elastic force is easily effective, that is, to the portions on both sides of the width direction W beyond the ends of the absorbent body 4 in the width direction W, in at least one of the ventral portion 3 and dorsal portion 2. This synergistically provides the effect of ensuring a good fit between the ventral portion 3 and dorsal portion 2, and consequently the disposable diaper 1, to the wearer's waist by multiple elastic members, as well as the effect of suppressing slippage by the anti-slip agent SC.

[0090] In a preferred embodiment of this design, the shear prevention agent SC is applied between the end of the absorbent body 4 in the longitudinal direction L and the outer end of the ventral body 3 and the dorsal body 2 (skin contact surfaces 3S and 2S) on at least one of the ventral body 3 and the dorsal body 2 (skin contact surfaces 3S and 2S). In the example shown in Figure 4, the shear prevention agent SC is applied (placed) between the end of the absorbent body 4 in the longitudinal direction L and the outer end of the ventral body 3 and the dorsal body 2 (skin contact surfaces 3S and 2S) on both the ventral body 3 and the dorsal body 2 (skin contact surfaces 3S and 2S).

[0091] Because this disposable diaper 1 has such a configuration, the anti-slip agent SC can support the absorbent body 8, which has become heavier after absorbing excreted urine, on at least one of the ventral portion 3 and the dorsal portion 2. As a result, even though the return stress in the width direction W of the combined ventral portion 3 and dorsal portion 2 is low, the slippage of the disposable diaper 1 from the wearer's waist can be more reliably suppressed.

[0092] In a preferred embodiment of this design, the shear prevention agent SC is applied continuously or intermittently from one end to the other in the width direction W of at least one of the ventral portion 3 and the dorsal portion 2. In the example shown in Figure 4, the shear prevention agent SC is applied continuously from one end to the other in the width direction W of both the ventral portion 3 and the dorsal portion 2.

[0093] Because this disposable diaper 1 has such a configuration, even if the return stress in the width direction W of the waist area is low, surface tension can prevent the disposable diaper 1 from slipping down from the wearer's waist. At the same time, it can suppress the occurrence of skin problems caused by pressure between the abdominal portion 3 and the dorsal portion 2 and the skin of the waist over a wide area of ​​the waist area, thereby suppressing skin problems.

[0094] In a preferred embodiment of this design, the shear prevention agent SC is applied to the longitudinal L and / or widthwise W ends of the absorbent body 8 contained in the absorbent body 4, overlapping in the thickness direction T. In the example shown in Figure 4, the shear prevention agent SC is applied to both the ventral and dorsal ends in the longitudinal L direction, and both the left and right ends in the width direction W of the absorbent body 8 contained in the absorbent body 4, overlapping in the thickness direction T.

[0095] In disposable diapers, the ends of the absorbent material 8 are highly rigid in the longitudinal direction L and / or the width direction W, while the parts outside the ends of the absorbent material 8 are less rigid. Due to this difference in rigidity, the ends of the absorbent material 8 are prone to causing pressure on the skin around the waist. Therefore, as described above, in this disposable diaper 1, an anti-slip agent SC is applied to the ends of the absorbent material 8 in the longitudinal direction L and / or the width direction W, where the rigidity is high. This suppresses the occurrence of skin problems caused by pressure on the skin around the waist from the ends of the absorbent material 8. At the same time, slippage can be suppressed by surface tension instead of friction.

[0096] In a preferred embodiment of this design, the ventral portion 3 and the dorsal portion 2 each include inner sheet members (inner sheets) 31 and 21 located on the skin side, with the skin-facing surfaces constituting the skin-contacting surfaces 3S and 2S. The inner sheet members 31 and 21 contain hydrophobic fibers. The shear prevention agent SC is a hydrophilic agent. The shear prevention agent SC is placed where hydrophobic fibers are present in the inner sheet members 31 and 21. In the example shown in Figure 4, the inner sheet members 31 and 21 include, for example, hydrophobic sheets in which the proportion of hydrophobic fibers in the constituent fibers is 70% by mass or more, as described above. The hydrophilic agent of the shear prevention agent SC includes, for example, an agent containing a hygroscopic water-retaining agent, as described above.

[0097] In this disposable diaper 1, the inner sheet members 31 and 21 in at least one of the ventral portion 3 and the dorsal portion 2 contain hydrophobic fibers, and a hydrophilic anti-slip agent is applied where the hydrophobic fibers are present. By applying the hydrophilic anti-slip agent SC to the areas where the hydrophobic fibers are present in the inner sheet members 31 and 21 in this way, it is possible to make it difficult for the anti-slip agent SC to penetrate the inner sheet members 31 and 21. As a result, the effects of the anti-slip agent SC applied to the inner sheet members 31 and 21, such as the effect of reducing chafing and the effect of suppressing slippage, can be made to produce an effect even with a small amount of the anti-slip agent, and the effect can be easily sustained.

[0098] The degree of hydrophilicity of the sheet material (sheet) can be measured by the following method. <Method for evaluating the hydrophilicity of sheet materials> (1) Cut the sheet material used in disposable diapers to a predetermined size (for example, 50 mm x 50 mm) and place it on the acrylic plate. (2) Drop 0.05 mL of colored water onto the cut sheet material from 30 mm above. After 10 minutes, measure the diffusion area of ​​the colored water using an image analysis device. A larger measured value indicates higher hydrophilicity compared to a smaller value.

[0099] In a preferred embodiment of this design, the shear prevention agent SC is not applied to the outer end in the longitudinal direction L of at least one of the ventral portion 3 and the dorsal portion 2.

[0100] Figure 5 is a plan view of the unfolded state showing another application example (modified version) of the anti-slip agent SC in the disposable diaper 1 according to the embodiment of Figure 1. In the example of Figure 5, compared to the example of Figure 4, the agent is not applied to the outer edges in the longitudinal direction L of both the ventral portion 3 and the dorsal portion 2. That is, there are uncoated areas 3WS and 2WS at the outer edges in the longitudinal direction L of both the ventral portion 3 and the dorsal portion 2. In this case as well, the same effect as in Figure 4 can be obtained.

[0101] Furthermore, when clothing comes into contact with the anti-slip agent SC, the fibers of the clothing can be adsorbed onto the SC, and if these adsorbed fibers accumulate, they may have adverse effects on the skin. Also, the adsorbed fibers may look like dirt, and consequently, the disposable diaper 1 may appear unsanitary. Therefore, in this disposable diaper 1, the anti-slip agent SC is not applied to the outer edge in the longitudinal direction L of at least one of the ventral portion 3 and the dorsal portion 2. Thus, it is possible to prevent clothing fibers from adsorbing onto the outer edge in the longitudinal direction L of the ventral portion 3 and the dorsal portion 2, which are prone to contact with the wearer's clothing. This suppresses adverse effects on the skin caused by adsorbed fibers and prevents the disposable diaper 1 from appearing unsanitary.

[0102] In a preferred embodiment of this design, the shear prevention agent SC is not applied to the inner end in the longitudinal direction L of at least one of the ventral portion 3 and the dorsal portion 2.

[0103] In the example in Figure 5, compared to the example in Figure 4, the coating is not applied to the outer edges in the longitudinal direction L of both the ventral portion 3 and the dorsal portion 2. That is, there are uncoated areas 3LS and 2LS at the inner edges in the longitudinal direction L of both the ventral portion 3 and the dorsal portion 2. In this case as well, the same effect as in Figure 4 can be obtained.

[0104] When clothing or the floor surface comes into contact with the anti-slip agent SC, the fibers of the clothing and dust from the floor surface can be adsorbed onto the anti-slip agent SC. If these adsorbed fibers and dust accumulate, they may have adverse effects on the skin. In addition, the adsorbed fibers and dust may look like dirt, and consequently, the disposable diaper 1 may become unsanitary. Therefore, in this disposable diaper 1, the anti-slip agent SC is not applied to the inner edge in the longitudinal direction L of at least one of the ventral portion 3 and the dorsal portion 2. Thus, it is possible to prevent the fibers of clothing and dust from the floor surface from adsorbing onto the inner edge in the longitudinal direction L of the ventral portion 3 and the dorsal portion 2, which are prone to contact with the wearer's clothing and the floor surface. This reduces adverse effects on the skin from adsorbed fibers and dust, and prevents the disposable diaper 1 from looking unsanitary.

[0105] Figure 6 is a plan view of the unfolded state showing another application example (modified version) of the anti-slip agent SC in the disposable diaper 1 according to the embodiment of Figure 1. In this embodiment, compared to the application example in Figure 4, the anti-slip agent SC is applied to at least one of the ventral portion 3 and the dorsal portion 2 in a location that does not overlap with the absorbent body 4. In this modified version, it is applied to both the ventral portion 3 and the dorsal portion 2. In this case as well, the same effect as in Figure 4 can be obtained. Note that in Figure 6, the anti-slip agent SC may be applied to only one of the ventral portion 3 and the dorsal portion 2.

[0106] Figure 7 is a plan view of the unfolded state showing another application example (modified version) of the anti-slip agent SC in the disposable diaper 1 according to the embodiment of Figure 1. In this embodiment, compared to the application example in Figure 4, the anti-slip agent SC is applied only to both outer sides in the width direction W of the absorbent body 4 on at least one of the ventral portion 3 and the dorsal portion 2, and is not applied to the outer side in the longitudinal direction L of the absorbent body 4. In this modified version, it is applied to both the ventral portion 3 and the dorsal portion 2. In this case as well, the same effect as in Figure 4 can be obtained. Note that in Figure 7, the anti-slip agent SC may be applied to only one of the ventral portion 3 and the dorsal portion 2. [Examples]

[0107] The present invention will be described below based on examples, but the present invention is not limited to these examples.

[0108] (1) Sample Example: As a disposable diaper, a size L pant-type disposable diaper according to the embodiment was prepared. A slip-preventing agent was applied to the disposable diaper at the position shown in Figure 4. As the slip-preventing agent, glycerin was used at a basis weight of 1.0 g / m² under conditions of a temperature of 20°C and a relative humidity of 60% RH. 2 The samples were coated and left to stand for 1.5 months under conditions of 20°C and 60% RH relative humidity. The elastic force of the elastic member around the waist of each disposable diaper in Examples 1 to 4 was adjusted to set the return stress to 0.010 N / mm, 0.016 N / mm, 0.023 N / mm, and 0.030 N / mm, respectively. Comparative Examples: Disposable diapers identical to those in the Examples were prepared. In Comparative Example 1, the same anti-slip agent as in the Examples was applied in the same amount. In Comparative Examples 2 and 3, no anti-slip agent was applied. The elastic force of the elastic member around the waist of each of the disposable diapers in Comparative Examples 1 to 3 was adjusted to set the return stress to 0.009 N / mm, 0.030 N / mm, and 0.032 N / mm, respectively.

[0109] (2) Evaluation Three subjects (infants (approximately 2 years old) with average body types based on the design of the pull-up type disposable diapers (size L)) were each fitted with the example and comparative example disposable diapers for a predetermined time (e.g., 3 hours). The skin on the back was visually observed before and after fitting to check for any shifting of the disposable diaper and for any marks left by the disposable diaper.

[0110] (3) Results The evaluation results are shown in Table 1 below. In Examples 1-4, when disposable diapers coated with an anti-slip agent were used, no shifting of the disposable diapers was observed, and no marks from the disposable diapers were observed. In Comparative Example 1, the return stress was small, so no marks were observed from the disposable diaper, but displacement was observed. In Comparative Example 2, the return stress was large, so no displacement of the disposable diaper was observed, but a slight mark was observed. In Comparative Example 3, the return stress was even larger, so no displacement of the disposable diaper was observed, but a mark was observed. Therefore, it was found that the presence of appropriate return stress and anti-slip agents can suppress slippage and improve fit, while also minimizing the impact on the wearer's skin and preventing skin problems.

[0111] [Table 1]

[0112] The disposable diapers of the present invention are not limited to the embodiments, examples, or modifications described above, and can be combined with or modified with those embodiments, examples, modifications, and known technologies, etc., without departing from the purpose and spirit of the present invention. [Explanation of Symbols]

[0113] 1. Disposable diapers 2 Dorsal part 3 Ventral part 4 Absorbent body 8 Absorbent 12,13 Elastic members SC Anti-Slip Agent

Claims

1. An absorbent article having longitudinal, widthwise, and thicknesswise directions that are mutually orthogonal in an unfolded state, comprising an abdominal portion that covers the wearer's abdomen, a dorsal portion that covers the wearer's back, and an absorbent body that covers the wearer's groin and includes an absorbent material, wherein the abdominal portion and the dorsal portion are joined together at both ends in the widthwise direction along the longitudinal direction to form a waist portion, and the absorbent body has front and rear ends in the longitudinal direction that extend to the central portion in the widthwise direction of the abdominal portion and the dorsal portion, respectively, The body circumference portion includes an elastic member that expands and contracts in the width direction, The return stress in the width direction of the body circumference is 0.010 N / mm to 0.030 N / mm. A slip-preventing agent is applied to the skin-contacting surface of the torso area. Absorbent material.

2. The aforementioned anti-slip agent contains 45% by mass or more of a hygroscopic humectant under conditions of a temperature of 20°C and a relative humidity of 60% RH. The absorbent article according to claim 1.

3. The aforementioned hygroscopic humectant contains glycerin. The absorbent article according to claim 2.

4. The basis weight of the aforementioned shear prevention agent is 0.3 g / m² or more and 2.5 g / m² or less. The absorbent article according to claim 2 or 3.

5. In a sliding tensile test, the sliding tensile stress is between 0.10 N / mm and 0.12 N / mm. The absorbent article according to any one of claims 1 to 3.

6. In the sliding tensile test, the sliding tensile stress is 1.05 times or more and 1.25 times or less the sliding tensile stress when the anti-slip agent is not applied to the skin contact surface of the body circumference. The absorbent article according to any one of claims 1 to 3.

7. The anti-slip agent is applied continuously or intermittently from one end to the other in the width direction of at least one of the ventral and dorsal portions. The absorbent article according to any one of claims 1 to 3.

8. The anti-slip agent is applied to the ends of the absorbent in the longitudinal and / or width directions so as to overlap in the thickness direction. The absorbent article according to any one of claims 1 to 3.

9. The anti-slip agent is not applied to the outer end in the longitudinal direction of at least one of the ventral and dorsal portions. The absorbent article according to any one of claims 1 to 3.

10. The anti-slip agent is not applied to the inner end in the longitudinal direction of at least one of the ventral and dorsal portions. The absorbent article according to any one of claims 1 to 3.

11. The anti-slip agent is applied to at least one of the ventral and dorsal portions of the absorbent body on both sides in the width direction, beyond the ends in the width direction of the absorbent body. The absorbent article according to any one of claims 1 to 3.

12. The anti-slip agent is applied between the longitudinal end and the longitudinal outer end of the absorbent body on at least one of the ventral and dorsal portions. The absorbent article according to any one of claims 1 to 3.

13. Each of the ventral and dorsal portions is located on the skin side and includes an inner sheet whose skin-facing surface constitutes the skin-contacting surface. The inner sheet contains hydrophobic fibers, The aforementioned anti-slip agent is a hydrophilic agent. The anti-slip agent is placed where the hydrophobic fibers are present in the inner sheet. The absorbent article according to any one of claims 1 to 3.

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