Absorbent article

Abstract

To provide a technology sufficiently preventing rubbing caused between an absorbent article and the skin in a real use.SOLUTION: An absorbent article is such one where a liquid-impermeable back sheet, an adsorbent part and a liquid-permeable top sheet are laminated in this order. The absorbent body includes an absorbent body and an encapsulating sheet encapsulating the absorbent body. The encapsulating sheet is disposed directly on the back sheet. The absorbent article has an easily slipping area where the absorbent part and the back sheet are not fixed in a thickness direction. When a dynamic friction coefficient between the skin of a wearer and the absorbent article is set to μ'1 and a dynamic friction coefficient between the absorbent part and the back sheet is set to μ'2, the relation ship of μ'1>μ'2 is satisfied. The encapsulating sheet has a thickness change rate of 30% or more before and after applying the load of 10 gf / cm2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to absorbent articles.

Background Art

[0002] Conventionally, as absorbent articles such as sanitary napkins, pantiliners, incontinence pads, etc., those in which a liquid-impermeable backsheet, an absorbent body part, and a liquid-permeable topsheet are laminated in this order are known. Since absorbent articles are worn in close contact with delicate parts of the skin, many wearers are concerned about rubbing between the absorbent article and the skin.

[0003] As a means for preventing rubbing, for example, there is an absorbent article using a topsheet with unevenness (for example, Patent Document 1). Also known are absorbent articles in which a drug such as a skin care agent is applied to the skin side of the topsheet (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The technologies disclosed in Patent Documents 1 and 2 are directed to devising a member that directly contacts the skin. Although such technologies can reduce damage to the skin caused by rubbing, they do not prevent rubbing itself. Therefore, a configuration that can prevent rubbing itself and improve the wearing feeling is required.

[0007] Regarding the prevention of rubbing, for example, it has also been studied in Patent Document 3 and Non-Patent Document 1, but there is room for study regarding the prevention of rubbing in a state where a load is applied from the skin side during actual use. For example, as the absorber part, it is common for the absorber body to be wrapped in a wrapping sheet, but there is room for study regarding the configuration of the wrapping sheet.

[0008] One aspect of the present disclosure aims to provide a technique for sufficiently preventing rubbing that may occur between an absorbent article and the skin during actual use.

Means for Solving the Problems

[0009] A first aspect of the present disclosure is an elongated absorbent article in which an impermeable backsheet, an absorber part, and a permeable topsheet are laminated in this order, the absorber part includes an absorber body and a wrapping sheet that wraps the absorber body, the wrapping sheet is disposed directly on the backsheet, the absorber part and the backsheet have a slippery region that is not fixed in the thickness direction, the coefficient of kinetic friction between the skin of the wearer and the absorbent article is μ'1, and the coefficient of kinetic friction between the absorber part and the backsheet is μ'2, and μ'1 > μ'2, and the rate of change in thickness of the wrapping sheet before and after the application of a load of 10 gf / cm 2 is 30% or more.

[0010] When the absorbent article is worn, the absorbent article is fixed to the underwear on the backsheet side. When the wearer's body moves, the underwear moves accordingly, and the absorbent article fixed accordingly also moves. At this time, as the entire absorbent article follows the movement of the underwear, rubbing occurs between the skin-side surface of the absorbent article and the inner thigh in contact with the skin-side surface. Therefore, when the absorbent article is worn for a long time or when the wearer makes intense movements, etc., it may cause discomfort due to rubbing and skin problems. On the other hand, according to the first aspect, the absorbent body portion has a slippery region that is not fixed to the backsheet. The presence of such a slippery region allows the absorbent body portion and the backsheet to slide relative to each other. In other words, the absorbent article according to this aspect has a structure inside that is slidable in the plane direction. As a result, even if the underwear moves as the wearer's body moves and the backsheet further moves following the movement of the underwear, the movement of the backsheet is difficult to be transmitted to the absorbent body portion or the structure from the absorbent body portion to the top surface (skin surface). That is, the structure from the absorbent body portion to the top surface and the structure from the absorbent body portion to the bottom surface (non-skin surface) can move independently of each other. Therefore, the structure from the absorbent body portion to the top surface can follow the skin of the inner thigh portion, and the structure from the absorbent body portion to the bottom surface can follow the underwear. Thus, according to this aspect, the relative movement between the wearer's skin and the skin-side surface of the absorbent article is reduced, and rubbing between the absorbent article and the skin can be prevented.

[0011] Furthermore, in this aspect, assuming that the coefficient of kinetic friction between the wearer's skin and the absorbent article is μ'1 and the coefficient of kinetic friction between the absorbent body portion and the backsheet is μ'2, μ'1 > μ'2. Therefore, the structure from the absorbent body portion to the topmost surface can more easily follow the skin of the wearer's inner thigh portion, and the effect of preventing rubbing between the absorbent article and the skin can be obtained more reliably. Rubbing between the skin and the absorbent article is particularly likely to be felt during an operation such as walking or running in which the body is continuously moved. Therefore, if it is easy to slide inside the absorbent article during the operation, the effect of suppressing rubbing is likely to be felt. Therefore, by having the relationship of the coefficient of kinetic friction as described above according to this aspect, rubbing can be prevented during walking or running operations.

[0012] In addition, since the absorbent body contained in the absorbent body portion is wrapped by a wrapping sheet, it is possible to prevent spillage of fibers, absorbent polymer particles, etc. contained in the main body. Further, it is possible to prevent fibers, absorbent polymer particles, etc. contained in the absorbent body from being exposed to the backsheet side and inhibiting the sliding between the absorbent body portion and the backsheet. Further, according to this aspect, since the wrapping sheet can be directly disposed on the backsheet, the ease of sliding between the absorbent body portion and the backsheet can be controlled by appropriately selecting the material of the wrapping sheet. In that case, for example, the absorbent article can be configured with a low number of components without interposing a layer for reducing friction or the like.

[0013] Furthermore, in this aspect, the above-described wrapping sheet is 10 gf / cm 2The sheet shall have a thickness change rate of 30% or more before and after load application. The absorbent article according to this aspect not only has the configuration of the above-mentioned slippery region and the relationship of the coefficient of kinetic friction (μ'1 > μ'2), but also includes a covering sheet having the above-mentioned predetermined thickness change rate, so that a satisfactory anti-slip effect can be obtained in actual use. The covering sheet is easily deformable itself. Therefore, in addition to the slippage between the absorbent body part and the back sheet described above, the deformation of the covering sheet itself causes deformation inside the absorbent article, specifically, relative movement in the plane direction between the absorbent body part and the back sheet is likely to occur. Also, even when a load is applied downward from the wearer's skin, the covering sheet can absorb the load, so the operation of starting to slip between the covering sheet and the back sheet also becomes smooth.

[0014] The second aspect of the present disclosure is the absorbent article according to the first aspect, wherein the ratio (μ'2 / μ'1×100) of the coefficient of kinetic friction μ'2 between the absorbent body part and the back sheet to the coefficient of kinetic friction μ'1 between the wearer's skin and the absorbent article is 95% or less.

[0015] According to the above second aspect, the anti-friction effect between the absorbent article and the skin can be obtained more reliably.

[0016] The third aspect of the present disclosure includes a central region including a body fluid discharge port facing portion facing the body fluid discharge port of the wearer, a front region in front of the central region, and a rear region behind the central region, and at least the central region is the slippery region, which is the absorbent article according to the first or second aspect.

[0017] The region where the absorbent article is likely to move when the wearer's body moves is the central region when viewed in the longitudinal direction. Therefore, according to the above third aspect, by making the central region the slippery region, the effect of preventing friction between the absorbent article and the skin can be improved.

[0018] The fourth aspect of the present disclosure is the absorbent article according to any one of the first to third aspects, wherein the slippery region is formed across the entire width direction of the absorbent article.

[0019] According to the above fourth aspect, the restriction of movement between the absorbent body part and the back sheet is eliminated across the entire width direction. Therefore, the relative sliding movement between the absorbent body part and the back sheet, particularly the sliding movement in the lateral direction, becomes easier.

[0020] The fifth aspect of the present disclosure is the absorbent article according to any one of the first to fourth aspects, wherein the coefficient of kinetic friction between the absorbent body part and the back sheet is 0.8 or less.

[0021] According to the above fifth aspect, since the friction during relative movement between the absorbent body part and the back sheet is reduced, the absorbent body part and the back sheet are more likely to slide in the plane direction relative to each other. Therefore, during the wearer's movement, the movement of the underwear is absorbed inside the absorbent body, and the effect of preventing rubbing between the absorbent article and the skin can be further improved.

[0022] The sixth aspect of the present disclosure is the absorbent article according to any one of the first to fifth aspects, wherein the area of the slippery region is 50% or more of the area of the overlapping region between the absorbent body part and the back sheet.

[0023] According to the above sixth aspect, by having a predetermined area of the slippery region, the effect of preventing rubbing between the absorbent article and the skin can be improved.

[0024] The seventh aspect of the present disclosure is the absorbent article according to the seventh aspect, wherein the covering sheet includes an air-through nonwoven fabric.

[0025] According to the above seventh aspect, the effect of preventing rubbing between the absorbent article and the skin can be further improved. In addition, since the covering sheet itself also has the ability to hold body fluids, it also contributes to reducing the amount of body fluids reaching the back sheet.

[0026] The eighth aspect of the present disclosure is that the amount of compression work measured by a compression tester for the encapsulated sheet is 0.10 gf·cm / cm 2 or more, and it is the absorbent article according to any one of the seventh to ninth aspects.

[0027] According to the above eighth aspect, the encapsulated sheet itself is easily deformed. Therefore, in addition to the slippage between the absorbent body part and the back sheet described above, the encapsulated sheet itself is deformed, so that deformation inside the absorbent article, specifically, relative movement in the plane direction between the absorbent body part and the back sheet is likely to occur. Further, even when a load is applied downward from the wearer's skin, the encapsulated sheet can absorb the load, so that the operation of starting to slip between the encapsulated sheet and the back sheet also becomes smooth.

[0028] The ninth aspect of the present disclosure has a fixing part in which the absorbent body part and the back sheet are fixed in the thickness direction, and the maximum value of the shear strain of the artificial skin piece measured by rubbing the artificial skin piece under a load in the thickness direction in the slippery region is τ N Let it be, and the maximum value of the shear strain measured under the same conditions as the measurement of τ N in the fixing part is τ B Let it be, and τ N <τ B and it is the absorbent article according to the first or second aspect.

[0029] In the above ninth aspect, in addition to the configuration described above in the first or second aspect, the maximum value τ N of the shear strain of the artificial skin piece in the slippery region and the maximum value of the shear strain in the fixing part are τ B and have a predetermined relationship (τ N <τ B ). The artificial skin piece is a substitute for the wearer's skin used for measuring the shear strain. Therefore, the above relationship of the shear strain (τ N <τ B ) means that the shear strain that can occur on the wearer's skin during wearing is reduced in the slippery region. Further, the fixing part has the above relationship of the shear strain (τ N <τ B) is also meant to be formed in an arrangement such that it can be obtained, i.e., within a range and at a position. Thus, by having the above shear strain relationship (τ N <τ B ), an absorbent article with reduced burden on the skin and high satisfaction regarding non-abrasion is provided.

[0030] The tenth aspect of the present disclosure includes a central region including a body fluid discharge port facing portion facing the body fluid discharge port of the wearer during wearing, a front region in front of the central region, and a rear region behind the central region. The absorbent body portion and the back sheet have a fixing portion fixed in the thickness direction. The ratio of the area of the fixing portion to the total area of the overlapping region of the absorbent body portion and the back sheet is less than 50%, and the fixing portion is provided in at least one of the front region and the rear region. The absorbent article according to the first or second aspect.

[0031] In the above tenth aspect, in addition to the configuration described above in the first or second aspect, since the area of the fixing portion is less than a predetermined ratio, the area of the above-mentioned slippery region is more than a predetermined ratio. Thereby, the above effects by the slippery region can be obtained more reliably. Also, although the slippery region is an excellent anti-abrasion mechanism, for some wearers, a feeling that the absorbent article floats from the underwear near the buttocks may occur, and it may be felt that the absorbent article is not stably worn, which may cause discomfort. This is presumably due to the fact that the back of the body moves more than the front, and the buttocks are likely to be in close contact with the absorbent article over a relatively large area because the absorbent article somewhat enters the creases of the buttocks, etc. Also, there are wearers who feel the above floating feeling in the front region. On the other hand, in this aspect, since the fixing portion where the absorbent body portion and the back sheet are fixed is formed in at least one of the front region and the rear region, the relative movement between the absorbent body portion and the back sheet can be suppressed in at least one of the front region and the rear region. In this way, according to this aspect, while maintaining the anti-abrasion effect, the discomfort that may be caused by the anti-abrasion mechanism can also be reduced, so that a comfortable wearing feeling can be obtained.

Advantages of the Invention

[0032] According to one aspect of the present disclosure, it is possible to provide a technique for sufficiently preventing rubbing between an absorbent article and the skin that may occur during wearing in actual use.

Brief Description of the Drawings

[0033]

Figure 1

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Best Mode for Carrying Out the Invention

[0034] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each drawing, unless otherwise specified, the same or corresponding components may be denoted by the same reference numerals and the description thereof may be omitted. Further, the drawings are schematic for facilitating understanding of the invention, and some dimensions may be shown enlarged or reduced.

[0035] The absorbent article according to the embodiment of the present disclosure may specifically be a sanitary napkin, a light incontinence pad, a pantiliner (sanitary sheet), a diaper, etc., but can be preferably used as a sanitary napkin. Hereinafter, this embodiment will be described based on an example of a sanitary napkin.

[0036] <Basic Configuration of Absorbent Article> FIG. 1 shows a plan view of an absorbent article 1 according to an embodiment of the present disclosure as viewed from the side facing the skin (skin side) when worn. Further, FIG. 2 shows a cross-section taken along line I-I of FIG. 1. In the cross-sectional view, the joining or fixing of the layers is shown in gray. That is, the gray portion indicates that the upper and lower members at that location are joined or fixed to each other.

[0037] As shown in FIGS. 1 and 2, the absorbent article 1 is formed by laminating an impermeable back sheet 2, an absorber portion 4, and a permeable top sheet 3 in this order. When wearing the absorbent article 1, the back sheet 2 side is fixed to underwear such as panties, and the top sheet 3 side comes into contact with the skin. A displacement preventing material (not shown) for fixing the absorbent article 1 to the underwear may be provided on the underwear side of the back sheet 2. In this specification, the back sheet 2 side of the absorbent article is also referred to as the underwear side or the lower side, and the top sheet 3 side is also referred to as the skin side or the upper side.

[0038] As shown in FIG. 1, the absorbent article 1 has an elongated shape having a predetermined length in the longitudinal direction D1 and a predetermined width in the width direction D2 orthogonal to the longitudinal direction D1, excluding the wings W, W extending from both side portions. In the absorbent article 1, the portion excluding the wings W, W may be referred to as the absorbent article main body. In the form shown in FIG. 1, the width of the absorbent article main body is substantially constant, but may vary in the longitudinal direction D1. Further, the absorbent article 1 shown in FIG. 1 has a shape and structure that is substantially line-symmetric with respect to the center line (longitudinal center line) CL extending in the longitudinal direction, but the structure of the absorbent article does not necessarily have to be line-symmetric.

[0039] Note that the length (total length) of the absorbent article 1 in the longitudinal direction D1 may preferably be 150 mm or more and 450 mm or less, more preferably 170 mm or more and 400 mm or less. Further, the thickness of the absorbent article main body (the portion including the absorbent body portion 4) may preferably be 0.3 mm or more and 30 mm or less, more preferably 1.0 mm or more and 15 mm or less, when measured at a location other than the location compressed in the thickness direction. However, a configuration in which the absorbent article main body is partially bulged may also be adopted by bulging the absorbent body portion 4 at the center in the width direction D2 of a part of the absorbent body portion 4, for example, the portion Q facing the body fluid discharge port and the region in the vicinity thereof, and the rear region.

[0040] The portion Q facing the body fluid discharge port is a portion that faces the body fluid discharge port such as the vaginal orifice of the wearer during wearing and is located on the longitudinal center line CL. The portion Q facing the body fluid discharge port may be in the range of 10 mm or more and 50 mm or less in the longitudinal direction D1 and 10 mm or more and 30 mm or less in the width direction D2, but the size of the portion Q facing the body fluid discharge port is not necessarily limited to the above range.

[0041] The absorbent article 1 may have a central region C including a body fluid discharge port facing portion Q, an end region Ef adjacent to one side of the central region C in the longitudinal direction D1 and extending to one edge of the longitudinal direction D1, and an end region Eb adjacent to the other side of the central region C in the longitudinal direction D1 and extending to the other edge of the longitudinal direction D1. The end regions Ef and Eb may be collectively referred to as an end region. Also, when the upper side in FIG. 1 is the front of the absorbent article 1 and the lower side is the rear of the absorbent article, the end region Ef is called the front region and the end region Eb is called the rear region.

[0042] The wings W, W are members for securely fixing the absorbent article 1 to underwear when worn, and extend from both sides of the central region C. The central region C may be a region from one edge (front edge) to the other edge (rear edge) of the longitudinal direction D1 of the wing W at the position where the wing W is connected to the absorbent article body (the base end of the wing W).

[0043] Note that one embodiment of the present disclosure may be an absorbent article without the wings W, W. In that case, when it is assumed that the wings W, W are formed, the region from one edge to the other edge at the base end of the wings W, W can be defined as the central region C.

[0044] On the skin side of the topsheet 3, side sheets 7, 7 extending in the longitudinal direction D1 along both side portions of the absorber portion 4 are overlaid. The side sheets 7, 7 extend outwards on both sides and are joined to the back sheet 2 extending outwards on both sides in the vertical direction to form the wings W, W. The joining of the side sheet 7 and the back sheet 2 may be formed by an adhesive as shown in FIGS. 2 and 3, or heat sealing, ultrasonic sealing, etc. may be used. The side sheets 7, 7 may extend inside the width direction D2 to form gathers.

[0045] In the form shown in FIG. 1, both the backsheet 2 and the topsheet 3 have the same length in the longitudinal direction D1 from the front end to the rear end of the absorbent article 1. On the other hand, the width of the topsheet 3 is smaller than the width of the backsheet 2. Further, the absorbent body portion 4 is provided sandwiched between the topsheet 3 and the backsheet 2 so as not to be exposed to the outside. For example, as shown in FIG. 1, the absorbent body portion 4 is arranged so as to fit within the backsheet 2 in plan view, that is, so as not to protrude from the backsheet 2. Further, the absorbent body portion 4 is configured and arranged so as to fit within the region where the topsheet 3 and the side sheets 7, 7 are provided. For example, the absorbent body portion 4 may protrude from the topsheet 3 at both ends in the width direction D2, but in that case, the protruding portions are covered by the side sheets 7, 7.

[0046] In the region around the absorbent body portion 4, the sheets may be joined to each other. For example, at both ends in the longitudinal direction D1 of the absorbent article 1, that is, in the regions where the absorbent body portion 4 extends beyond in the longitudinal direction D1, the topsheet 3 and the backsheet 2 may be joined by joining means such as an adhesive such as hot melt, heat seal, ultrasonic seal, etc. Further, at the ends in the width direction D2 of the absorbent body portion 4 along the longitudinal direction D1, the side sheet 7 and / or the topsheet 3 and the backsheet 2 may be joined by the above joining means. In this way, the periphery of the absorbent body portion 4 may be sealed over the entire circumference. Thereby, it is possible to prevent the body fluid absorbed by the absorbent body portion 4 from leaking in the direction along the surface direction (from the side), and also to enhance the shape stability of the absorbent article 1.

[0047] As the backsheet 2, at least a sheet material having water shielding properties such as an olefin resin sheet such as polyethylene or polypropylene can be used. A laminated nonwoven fabric obtained by laminating a nonwoven fabric on a polyethylene sheet or the like, or a laminated sheet of a nonwoven fabric having substantially liquid impermeability with a waterproof film interposed therebetween can be used. Further, from the viewpoint of preventing stuffiness, it is more desirable to use a material having moisture permeability. As such a water shielding and moisture permeable sheet material, a microporous sheet obtained by melt-kneading an inorganic filler in an olefin resin such as polyethylene or polypropylene, forming a sheet, and then stretching it in a uniaxial or biaxial direction can be used.

[0048] The topsheet 3 is a liquid-permeable sheet that quickly permeates body fluids such as menstrual blood, vaginal discharge, and urine. As the topsheet 3, a porous or non-porous nonwoven fabric, a porous plastic sheet, or the like is preferably used. Examples of the material fibers constituting the nonwoven fabric include olefins such as polyethylene and polypropylene, synthetic fibers such as polyester and polyamide, regenerated fibers such as rayon and cupra, and blended fibers thereof, and natural fibers such as cotton, which can be used alone or in combination of two or more. Examples of the processing method of the nonwoven fabric include the spunlace method, the spunbond method, the thermal bond method, the meltblown method, and the needle punch method. Among these processing methods, the spunlace method is preferable in that it can produce a nonwoven fabric rich in flexibility, and the spunbond method is preferable in that it can produce a nonwoven fabric rich in drapability. The thermal bond method is preferable in that it can produce a bulky and soft nonwoven fabric. Further, composite fibers such as core-sheath type fibers, side-by-side type fibers, and split type fibers, in which fibers with a high melting point are used as the core and fibers with a low melting point are used as the sheath, can be used.

[0049] As the side sheet 7, a water-repellent treated nonwoven fabric or a hydrophilic treated nonwoven fabric can be used. For example, when enhancing the effect of preventing penetration of menstrual blood, vaginal discharge, etc. or the tactile sensation, it is preferable to use a water-repellent treated nonwoven fabric coated with a silicone-based or paraffin-based water-repellent agent or the like. Further, when enhancing the absorbency of menstrual blood or the like in the wing W, it is preferable to use a hydrophilic treated nonwoven fabric as the material of the nonwoven fabric. As the type of nonwoven fabric, an air-through nonwoven fabric that is difficult to get creases, is difficult to wrinkle, and is soft is preferable.

[0050] As shown in FIG. 2, the absorbent body portion 4 has a configuration including an absorbent body main body 4a that substantially bears the function of absorbing body fluid, and a covering sheet 4b that covers the absorbent body main body 4a. Due to the structure in which the absorbent body main body 4a is wrapped by the covering sheet 4b, it is possible to prevent the fibrous or granular material contained in the absorbent body main body 4a from spilling out, and it is also possible to prevent the absorbent body portion 4 as a whole from sagging or cracking, that is, the shape retention property is also improved.

[0051] The width of the absorbent body portion 4 may be constant over the longitudinal direction D1, or may gradually narrow at the front and rear as shown in FIG. 1. In this specification, the width of the absorbent body portion 4, or the width of the region where the absorbent body portion 4 and the back sheet 2 overlap refers to the width of the region other than the portions that gradually narrow at the front and rear.

[0052] The absorber body 4a is not limited as long as it is a material capable of absorbing and retaining body fluids, but preferably contains cotton-like pulp and a water-absorbing polymer. As the water-absorbing polymer, superabsorbent polymer granular powder (superabsorbent polymer (SAP)), superabsorbent polymer fiber (superabsorbent fiber (SAF)), and combinations thereof can be used. Examples of the pulp include those made of cellulose fibers such as chemical pulp obtained from wood, dissolving pulp, artificial cellulose fibers such as rayon and acetate, and recycled pulp and recycled fibers can also be used. As raw materials for chemical pulp, hardwoods, softwoods, etc. are used, and softwoods are preferably used because of their long fiber length. The absorber body 4a can be manufactured by stacking or air-laying methods.

[0053] In addition, synthetic fibers may be mixed in the absorber body 4a. As the synthetic fibers, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon, and copolymers thereof can be used, and two of these can be mixed and used. Also, composite fibers such as core-sheath fibers having a high-melting-point fiber as the core and a low-melting-point fiber as the sheath, side-by-side fibers, and split fibers can be used. In addition, those obtained by surface-treating hydrophobic fibers with a hydrophilizing agent to impart affinity for body fluids can also be used.

[0054] The encapsulating sheet 4b is made to be highly flexible so that it can absorb the load from the body when the absorbent article 1 is worn, and the thickness change rate before and after load application is high. By the encapsulating sheet 4b absorbing the load, the force with which the encapsulating sheet 4b is pressed against the back sheet 2 is weakened, and sufficient relative sliding (described in detail later) between the encapsulating sheet 4b and the back sheet 2 becomes possible.

[0055] The thickness change rate of the encapsulating sheet 4b before and after load application is 30% or more. The thickness change rate may preferably be 50%. The above thickness change rate is 10 gf / cm2 It may be calculated from the thickness before and after load application. Further, the measurement can be performed by a compression tester such as a KES compression tester.

[0056] Further, the wrapping sheet 4b may have a high compression work amount. The compression work amount (WC) of the wrapping sheet 4b measured by a compression tester, for example, a KES compression tester, is preferably 0.10 gf·cm / cm 2 or more, more preferably 0.17 gf·cm / cm 2 or more.

[0057] Further, the basis weight of the wrapping sheet 4b may preferably be 8 gsm or more and 35 gsm or less, more preferably 12 gsm or more and 25 gsm or less, still more preferably 16 gsm or more and 20 gsm or less. Further, when the wrapping sheet 4b is a non-woven fabric, particularly an air-through non-woven fabric, the fineness of the fibers used in the wrapping sheet 4b may preferably be 3.3 dtex or more and 7.8 dtex or less.

[0058] The material of the wrapping sheet 4b is not particularly limited as long as the rate of change in thickness is 30% or more as described above, and may be a non-woven fabric, paper, or the like. As the non-woven fabric, an air-through non-woven fabric, a spunbond non-woven fabric, a softened spunbond non-woven fabric, or the like is used. As the paper, crepe paper is used. Among these, an air-through non-woven fabric is preferable because it can reduce the coefficient of kinetic friction μ'2 (described in detail later) between the absorber portion 4 and the back sheet 2 and is flexible. Further, the air-through non-woven fabric is also preferable from the viewpoint of preventing leakage because it has a high function of retaining body fluid.

[0059] An intermediate sheet 5 may be provided between the top sheet 3 and the absorber portion 4 to assist the downward and / or lateral transfer and diffusion of body fluid that has reached the non-skin surface of the top sheet 3, but the intermediate sheet 5 can also be omitted. When the intermediate sheet 5 is provided, as the material of the intermediate sheet 5, for example, the same material as that of the top sheet 3 described above can be used.

[0060] Although illustration is omitted, the absorbent article main body may have a squeezing groove (fit emboss) that depresses from the top sheet 3 side toward the back sheet 2 side by a method known in the art. Due to the presence of the squeezing groove, the top sheet 3 and the absorbent body portion 4, or the top sheet 3, the intermediate sheet 5, and the absorbent body portion 4 are joined vertically, so that they can deform and move integrally even when a force is applied.

[0061] <Joining of the absorbent body portion and the back sheet> The absorbent article 1 according to an embodiment of the present disclosure has a region where the absorbent body portion 4 and the back sheet are not fixed in the thickness direction. Here, first, the joining and fixing of the absorbent body portion and the back sheet in the absorbent article according to the prior art will be described with reference to FIGS. 3 and 4. FIG. 3 is a plan view of the absorbent article 1' according to the prior art as viewed from the skin side, and FIG. 4 is a cross-sectional view taken along line II-II of FIG. 3. The absorbent article 1' according to the prior art also has a basic structure similar to that of the absorbent article 1 described above.

[0062] As shown in FIG. 3, in the absorbent article 1', the absorbent body portion 4 and the back sheet 2 are fixed to each other in the thickness direction at the fixing portion 8. In FIG. 3, the range of the fixing portion 8 is shown by a matte pattern. The fixing portion 8 is provided continuously in a strip shape over the longitudinal direction D1, more specifically, from one end to the other end of the longitudinal direction D1. The fixing portion 8 shown in FIG. 3 is composed of a plurality of annular adhesive application portions that are shifted and overlapped in the longitudinal direction D1. The adhesive application portion may be formed by an adhesive such as hot melt, for example. At the position where the fixing portion 8 is formed, the absorbent body portion 4 and the back sheet 2 cannot move relative to each other in the plane direction.

[0063] Here, the annular adhesive application portion is such that the adhesive is applied on the circumference of the circle, and no adhesive is applied inside the circle. Since no adhesive is applied in the inner region of the circle, the absorber portion 4 and the backsheet 2 are not joined inside the circle. However, since they are surrounded by the annular adhesive application portion, it becomes a region where the absorber portion 4 and the backsheet 2 cannot move relative to each other, and it is included in the fixing portion. Note that as the fixing portion 8, instead of the annular adhesive application portion, an adhesive application portion where the adhesive is solidly applied in a circular shape may be provided.

[0064] The fixing portion 8 extends in a strip shape, two on each side of the longitudinal center line CL, and both have substantially the same width. In the absorbent article 1', for example, between the strip-shaped fixing portions 8, the absorber portion 4 and the backsheet 2 are not joined, but such portions are few. In the absorbent article 1', generally, the absorber portion 4 is fixed to the backsheet 2, and the absorber portion 4 and the backsheet 2 move integrally in the plane direction. Therefore, in the absorbent article 1', the relationship of the coefficient of kinetic friction μ'1 > μ'2 described later cannot be obtained. Also, in general, in the absorbent article main body, a squeezing groove (not shown) is formed by squeezing in the thickness direction after laminating the members (in the illustrated example, the absorber portion 4, the intermediate sheet 5, and the top sheet 3) from the absorber portion 4 to the topmost surface. Therefore, even when a force is applied in the direction of shearing the absorbent article 1', the members cannot slide relative to each other in the plane direction within the structure from the backsheet 2 to the top sheet 3.

[0065] Therefore, when the wearer moves the body while wearing the absorbent article 1', for example, when performing a walking motion of alternately moving the legs forward and backward, the underwear deforms as the legs move forward and backward. At this time, the entire absorbent article 1' follows the deformation of the underwear. Then, inevitably, friction occurs between the absorbent article 1' and the inner thigh portion of the wearer facing the absorbent article 1'. Also, even if no friction occurs, the skin of the inner thigh portion in close contact with the absorbent article 1' is pulled in the shearing direction by the absorbent article 1', and a burden is likely to be imposed on the skin.

[0066] In contrast, in the absorbent article according to an embodiment of the present disclosure, the absorbent body portion 4 has a slippery region NB that is not fixed to the back sheet 2 in the thickness direction. The slippery region NB is a region other than the fixing portion 8, and may also be referred to as a non-fixed region. The slippery region NB may preferably be formed substantially over the entire width direction D2. Further, in the absorbent article 1, as shown in FIG. 1, the slippery region NB is formed in a region that extends in the longitudinal direction D1 from the middle of one end region Ef through the central region C to the middle of the other end region Eb. That is, in the absorbent article 1, most of the absorbent body portion 4 and the back sheet 2 are not fixed to each other in the thickness direction, and in the overlapping region of the absorbent body portion 4 and the back sheet 2, the fixing portions 8 are only slightly formed at both ends in the longitudinal direction D1.

[0067] In the absorbent article 1, the rate of change in thickness of the covering sheet 4b before and after the application of a load is a predetermined value or more, and due to the formation of the slippery region NB, the absorbent body portion 4 and the back sheet 2, specifically the covering sheet 4b and the back sheet 2, can slide relative to each other sufficiently even during actual use. Therefore, the configuration from the absorbent body portion 4 to the top surface can follow the skin while remaining in close contact with the skin, and the back sheet 2 can follow the underwear. Thus, even if the underwear moves as the wearer's body moves and the back sheet 2 moves as the underwear moves, the structure from the absorbent body portion 4 to the top surface can maintain a stable state while remaining in close contact with the skin in the crotch portion. Therefore, rubbing of the skin by the absorbent article 1 during wearing is reduced, and an excellent wearing feeling that could not be obtained by simply devising the configuration of the top sheet can be obtained.

[0068] In addition, in this specification, when it is said that the slippery region NB is "formed substantially over the entire width direction", it means that as long as the effect of preventing rubbing during wearing without interfering with the sliding between the absorber portion 4 and the backsheet 2 is not impaired, the formation of the fixing portion 8 that fixes the absorber portion 4 and the backsheet 2 in the width direction D2 is allowed. For example, it refers to a form in which the total length of the fixing portion 8 in the width direction D2 is 20% or less, preferably 10% or less, more preferably 5% or less of the overlapping region between the absorber portion 4 and the backsheet 2 or the length of the absorber portion 4 in the width direction D2 as viewed in the width direction D2. For example, the form in which the fixing portion 8 is formed at both end edges of the absorber portion 4 in the width direction D2 with the length in the width direction D2 within the above range may be included. However, when the absorber portion 4 and the backsheet 2 are not joined over the entire width direction D2, that is, when the slippery region NB is formed over the entire width direction, the relative movement (sliding) between the absorber portion 4 and the backsheet 2 becomes easier, which is preferable.

[0069] As shown in FIGS. 1 and 2, in the absorbent article 1, the absorber portion 4 and the backsheet 2 are not joined throughout the entire central region C, and there is no fixing portion 8. That is, the central region C is the slippery region NB. In other words, the entire central region C is included in the slippery region NB. Since the skin facing the central region C is particularly likely to feel rubbed, by making the central region C the slippery region NB, the evaluation regarding rubbing can be effectively enhanced.

[0070] Note that the absorbent article 1 may not be provided with the fixing portion 8 between the absorbent body portion 4 and the back sheet 2. That is, the absorbent body portion 4 and the back sheet 2 are not joined and fixed throughout, and all of the overlapping regions between the absorbent body portion 4 and the back sheet 2 may be slippery regions NB. This form is preferable from the viewpoint of preventing rubbing because the slide between the absorbent body portion 4 and the back sheet 2 becomes easy. On the other hand, in view of the shape retention of the absorbent article 1 when worn for a long time or the like, it is preferable that the fixing portion 8 is formed. However, the fixing portion 8 needs to be formed at a position and within a range that does not prevent the relative movement between the absorbent body portion 4 and the back sheet 2. When the fixing portion 8 is provided, as shown in FIG. 1, it is preferably formed at one or both ends in the longitudinal direction D1 of the overlapping region between the absorbent body portion 4 and the back sheet 2.

[0071] The area of the slippery region NB (the area of the region other than the fixing portion 8) may preferably be 50% or more, more preferably 70% or more, and even more preferably 90% or more with respect to the area of the overlapping region between the absorbent body portion 4 and the back sheet 2.

[0072] Also, the total area of the fixing portion 8 where the absorbent body portion 4 and the back sheet 2 are fixed in a plan view may preferably be less than 50%, more preferably less than 30%, and even more preferably less than 10% with respect to the area of the overlapping region between the absorbent body portion 4 and the back sheet 2.

[0073] Some member may be sandwiched between the absorbent body portion 4 and the back sheet 2, but as shown in FIG. 2 and the like, it is preferable that the absorbent body portion 4 is directly laminated on the back sheet 2 without the intervention of other members. When laminated without the intervention of other members, a simple configuration with a small number of members can obtain a good effect of preventing rubbing.

[0074] <Coefficient of friction> Furthermore, in the absorbent article 1, the coefficient of kinetic friction between the wearer's skin and the absorbent article 1 is μ'1, and the coefficient of kinetic friction between the absorbent body part 4 and the back sheet 2 is μ'2, and μ'1 > μ'2. Here, as described above, since the absorbent body part 4 is configured such that the absorbent body main body 4a is wrapped by the covering sheet 4b, the covering sheet 4b is directly laminated on the back sheet 2, that is, in direct contact with the back sheet 2. Therefore, the coefficient of kinetic friction μ'2 between the absorbent body part 4 and the back sheet 2 is the coefficient of kinetic friction between the covering sheet 4b and the back sheet 2.

[0075] When the absorbent article 1 has the above relationship of the coefficient of kinetic friction (μ'1 > μ'2), when the absorbent article 1 is worn in close contact with the wearer's skin, rather than a relative slide occurring between the absorbent article 1 and the skin, a slide between the absorbent body part 4 and the back sheet 2, that is, between the covering sheet 4 and the back sheet 2, is more likely to occur. Therefore, the structure from the absorbent body part 4 to the top surface can easily follow the skin of the crotch part, and the effect of preventing rubbing between the absorbent article 1 and the skin can be obtained more reliably. In particular, since the regulation of the coefficient of kinetic friction relates to the friction when the wearer is moving rather than starting to move, by having the relationship of the coefficient of kinetic friction (μ'1 > μ'2), the effect of suppressing rubbing in an operation of continuously moving the body such as walking or running can also be improved. Note that since the absorbent article 1 according to the present embodiment includes the covering sheet 4b having a predetermined thickness change rate, the relationship of the friction coefficient can be obtained during actual use when a load is applied from the skin side.

[0076] Note that the coefficient of friction (including the coefficient of kinetic friction and the coefficient of static friction) in this specification can be measured using a friction measuring device, for example, TriboMaster μv1000, TL201Tt, etc. manufactured by Trinity Lab Co., Ltd. When measuring the coefficient of friction between the wearer's skin and the absorbent article using a friction measuring device, the entire absorbent article is placed on the stage of the friction measuring device. When measuring the coefficient of friction between the absorbent body part and the back sheet, the absorbent body part and the back sheet part are taken out from the absorbent article (in a state where the top sheet and the intermediate sheet are removed) and placed on the stage of the friction measuring device. When the absorbent body part is composed of an absorbent body main body and a wrapping sheet, the wrapping sheet and the back sheet part may be taken out and placed on the stage of the friction measuring device. Also, when measuring the coefficient of friction between the absorbent body part and the back sheet, the measurement may be performed on any region of the absorbent article, but preferably, it is performed in the central region C facing the crotch part where rubbing is likely to be a concern. Then, in the measurement of the coefficient of friction between the wearer's skin and the absorbent article and the measurement of the coefficient of friction between the absorbent body part and the back sheet, the measurement location (the location where the contactor of the friction measuring device contacts) is the same in plan view. For example, if the coefficient of friction between the wearer's skin and the absorbent article is measured near the center in the width direction of the central region C, the measurement of the coefficient of friction between the absorbent body part and the back sheet is also performed near the center in the width direction of the central region C in the same manner.

[0077] For measuring the coefficient of friction between the wearer's skin and the absorbent article, the above-described friction measuring device can be used, and as shown in Fig. 5(a), it can be performed using an artificial skin piece 55 as a substitute for the skin. As the artificial skin piece 55, a commercially available one may be used, or it may be manufactured for measurement. The artificial skin piece 55 may be a plate-shaped piece made of a resin such as urethane resin and having a hardness of about Asker C hardness 15. Also, as shown in Fig. 5(b), the shape of the artificial skin piece 55 is such that the side (lower side) facing the absorbent article simulating the body bulge is a spherical shape convex downward. An example of the artificial skin piece has a shape and size of length a = 97 mm × width b = 50 mm × minimum thickness t = 12 mm, and a spherical shape convex downward with a curvature radius of 150 mm on the lower side.

[0078] The ratio (μ'2 / μ'1×100) of the dynamic friction coefficient μ'2 between the absorbent body part 4 and the back sheet 2 to the dynamic friction coefficient μ'1 between the wearer's skin and the absorbent article 1 is preferably 95% or less, more preferably 80% or less, and even more preferably 70% or less. When the ratio of the dynamic friction coefficient μ'2 to the dynamic friction coefficient μ'1 is within the above range, the absorbent body part 4 and the back sheet 2 slide preferentially when the wearer is moving, and the structure from the absorbent body part 4 to the top surface can more easily follow the skin, improving the effect of preventing rubbing. In this specification, the dynamic friction coefficient is the average friction coefficient measured in a steady state.

[0079] The dynamic friction coefficient μ'2 between the absorbent body part 4 and the back sheet 2 is preferably 0.8 or less, more preferably 0.60 or less. When the dynamic friction coefficient μ'2 is within the above range, it becomes easier to slide between the absorbent body part 4 and the back sheet 2, so the effect of preventing rubbing can be improved.

[0080] Also, taking the static friction coefficient between the wearer's skin and the absorbent article 1 as μ1 and the static friction coefficient between the absorbent body part 4 and the back sheet 2 as μ2, μ1>μ2 may hold. Thereby, when the wearer starts to move, sliding between the absorbent body part 4 and the back sheet 2 is more likely to occur preferentially than relative sliding between the absorbent article 1 and the skin, and the structure from the absorbent body part 4 to the top surface can more easily follow the skin of the crotch part, improving the effect of preventing rubbing between the absorbent article 1 and the skin. In the absorbent article 1 according to the present embodiment, since the covering sheet 4b of the absorbent body part 4 and the back sheet 2 are in contact, the static friction coefficient μ2 between the absorbent body part 4 and the back sheet 2 is specifically the static friction coefficient between the covering sheet 4b and the back sheet 2.

[0081] Note that the encapsulated sheet 4b that contacts the backsheet 2 may be used without treatment, but it can also be subjected to a friction reduction treatment. The friction reduction treatment is, for example, a treatment of applying or adhering a substance capable of imparting lubricity to the surface of the encapsulated sheet 4b facing the backsheet 2. In the friction reduction treatment, a liquid containing a treatment substance may be applied to the surface of the encapsulated sheet 4b facing the backsheet 2, or a film-like treatment substance may be adhered. As an example of the friction reduction treatment, silicone coating can be mentioned. The coating liquid for silicone coating may be a silicone resin, methylpolysiloxane, highly polymerized methylpolysiloxane, poly(oxyethylene·oxypropylene)methylpolysiloxane copolymer, etc. Also, the friction reduction treatment may be a fluororesin coating or the like. The amount of the substance imparted by the friction reduction treatment may be 0.1 g / m 2 or more and 30 g / m 2 or less (in a dry state).

[0082] The above friction reduction treatment may be applied to the surface of the backsheet 2 facing the absorber portion 4 or the encapsulated sheet 4b. Also, it may be applied to both the encapsulated sheet 4b and the backsheet 2.

[0083] Also, when the encapsulated sheet 4b and / or the backsheet 2 is subjected to a friction reduction treatment and a fixing portion 8 such as an adhesive for joining the encapsulated sheet 4b and the backsheet 2 is provided, it is preferable not to apply the friction reduction treatment to the position where the fixing portion 8 is to be provided.

[0084] <Shearing strain> Furthermore, for the absorbent article 1 according to the present embodiment, the maximum value of the shearing strain of the artificial skin measured by rubbing the artificial skin piece under a load in the thickness direction at the fixing portion 8 is τ B and the maximum value of the shearing strain measured under the same conditions as the measurement of the above τ B in the easy-sliding region is τ N and it has the characteristic that τ N <τ B Here, since the artificial skin piece serves as a substitute for the skin, τ N<τ B This relationship means that, in a state where the absorbent article 1 is worn in a close contact state, the burden on the skin in the slippery area NB is reduced. Even if there is no actual rubbing occurring to the wearer, the wearer may feel a burden on the skin due to the force received in the shearing direction from the closely attached absorbent article, and the wearer may feel a sensation as if rubbing is occurring or about to occur. In that case, the satisfaction level when evaluating the absence of rubbing tends to be impaired. On the other hand, in the absorbent article 1 according to the present embodiment, the burden on the skin can be reduced, and the satisfaction level regarding the absence of rubbing as described above can be improved.

[0085] For the measurement of shear strain, the friction test device 50 (Fig. 5(a)) described as a device available for the measurement of the coefficient of friction can be used. The measurement of shear strain can be performed as follows. First, prepare a predetermined artificial skin piece 55, bring the artificial skin piece 55 into contact with and face the skin surface of the absorbent article 1, and slide and rub the artificial skin piece 55 and the absorbent article 1 relative to each other in one direction in the longitudinal direction of the absorbent article 1 under predetermined conditions. At that time, in order to simulate the situation where the absorbent article is attached to underwear, it is preferable that the absorbent article 1 is placed on the stage 51 after attaching a cloth such as a muslin cloth 52 to its non-skin side. Also, for the relative slide, either the artificial skin piece 55 or the stage 51 of the friction test device 50 on which the absorbent article 1 is arranged may be moved. For example, as shown in Fig. 5(a), the stage 51 is moved in the slide direction Ds. The above slide is performed with a load applied to the artificial skin piece 55. An example of the predetermined conditions during the slide can be a vertical load (thickness direction load) applied: 9.8 N, slide speed: 5.3 mm / s, slide distance: 15 mm.

[0086] Then, during the slide, the side surface of the artificial skin piece 55 is photographed over time, and the shear strain is obtained by the digital image correlation method. The digital image correlation method (DICM) is a known method used for measuring strain and the like. In the measurement of the shear strain of the artificial skin piece in this embodiment, a random dot pattern (speckle pattern) is applied to the side surface of the artificial skin piece by spraying paint or the like, and the side surface is photographed over time with a camera 58 such as a high-speed camera, and the photographed image is analyzed. Thereby, the change over time of the shear strain of the artificial skin piece 55 can be obtained. Although there is a distribution in the shear strain within the analysis region, the value of the absolute value of the maximum shear strain within the analysis region of the artificial skin piece and within the entire measurement time is recorded as the maximum value of the shear strain.

[0087] Such measurement of the shear strain of the artificial skin piece is performed at the position where the fixing portion 8 is disposed and the position where the slippery region NB is disposed in a plan view in one absorbent article, respectively. Then, the artificial skin piece is rubbed under a load in the thickness direction, and the maximum value of the shear strain of the artificial skin piece measured under the same conditions can be obtained for each of the slippery region NB and the fixing portion 8. That is, the maximum value τ of the shear strain measured in the slippery region NB N and the maximum value τ of the shear strain measured at the fixing portion 8 B can be obtained.

[0088] The ratio (τ of the maximum value τ of the shear strain measured in the slippery region NB N to the maximum value τ of the shear strain measured at the fixing portion 8 B (τ N / τ B × 100) may preferably be 95% or less, more preferably 90% or less, and still more preferably 85% or less. When the ratio is within the above range, the relative slide between the absorber portion 4 and the back sheet 2 in the slippery region NB becomes easy, the anti-friction effect is high, and an absorbent article that suppresses the burden on the skin can be provided even if rubbing has not actually occurred.

[0089] Furthermore, for the absorbent article 1 according to the present disclosure, the maximum value of the shear strain of the artificial skin piece measured by bringing the artificial skin piece into contact with the skin side in the slippery region NB of the absorbent article 1 is τ, and the artificial skin piece is brought into contact with the skin side of a control absorbent article having no slippery region NB, and the maximum value of the shear strain of the artificial skin piece measured under the same conditions as the maximum value τ of the shear strain is τc, and it may have the feature that τ < τc. Since the artificial skin piece is a substitute for the skin as described above, the relationship τ < τc regarding the maximum value of the shear strain measured using the artificial skin piece means that when the absorbent article 1 is in close contact and the skin of the wearer and the absorbent article move relatively in the shear direction, the shear strain that can occur in the skin of the wearer is reduced compared to conventional products. In conventional products, even if there is no actual rubbing, the skin feels a burden when receiving a force in the shear direction from the closely attached absorbent article, and the wearer feels a feeling of rubbing or a feeling of being about to rub, and the satisfaction when evaluating the absence of rubbing tends to be impaired. On the other hand, in the absorbent article 1 according to the present embodiment, the burden on the skin can be reduced, and the satisfaction regarding the absence of rubbing can also be improved.

[0090] In addition, the conventional product used as the control absorbent article may be a product in which the absorbent body portion 4 and the back sheet 2 are entirely fixed in the thickness direction. The control absorbent article (conventional product) may be the absorbent article 1' shown in FIGS. 3 and 4, in which the absorbent body portion 4 and the back sheet 2 are fixed in the thickness direction over the longitudinal direction D1.

[0091] In addition, an embodiment of the present disclosure is an elongated absorbent article in which an impermeable back sheet, an absorbent body portion, and a permeable top sheet are laminated in this order, having a slippery region where the absorbent body portion and the back sheet are not fixed, the maximum value of the shear strain of the artificial skin piece measured by rubbing the artificial skin piece on the skin side of the absorbent article is τ, and the artificial skin piece is brought into contact with the skin side of a control absorbent article having no slippery region, and the maximum value of the shear strain of the artificial skin piece measured under the same conditions as the maximum value τ of the shear strain is τc, and it may be an absorbent article where τ < τc.

[0092] The ratio (τ / τc×100) of the maximum value τ of the shear strain of the artificial skin piece measured by bringing the artificial skin piece into contact with the skin side of the absorbent article 1 to the maximum value τc of the shear strain measured under the same conditions as the maximum value τ of the shear strain by bringing the artificial skin piece into contact with the skin side of the control absorbent article is preferably 95% or less, more preferably 90% or less, and even more preferably 80% or less. By the range of the above ratio, it is possible to provide the absorbent article 1 in which the burden on the skin during wearing is more reliably reduced as compared with conventional absorbent articles.

[0093] <Formation of the fixing part in the manufacturing process> The above-described fixing part 8, which is a part where the absorber part 4 and the back sheet 2 are fixed in the thickness direction, can be provided by applying an adhesive using melt coating by a hot melt coater or the like on the production line. More specifically, a gravure coater, a spray coater, a spiral gun, a bead gun, or the like can be used. Fig. 6 shows a part of the process in the production line for obtaining the absorbent article 1 shown in Fig. 1. As shown in Fig. 6, a long back sheet strip 2A is conveyed so that the longitudinal direction becomes the conveyance direction Dt, and at this time, the cutting planned contours (dashed-dotted lines) of a plurality of absorbent articles 1 to be cut out later are determined. Then, the adhesive Ad1 is applied so as to span one end portion in the longitudinal direction D1 of one absorber part 4 and the other end portion of the absorber part 4 subsequent to the absorber part 4. In the example shown in Fig. 6, the adhesive Ad1 is applied along the conveyance direction Dt of the absorbent article 1 such that a plurality of annular adhesive application portions are shifted by the length of their radius in the conveyance direction Dt and overlap each other. The shape of the adhesive application portion is not limited to that shown in the figure, and may be polygonal or any other shape, or may be linear, curved, or spiral, or may be by solid coating of a predetermined shape.

[0094] Thereafter, the intermediate sheet 5 is optionally overlaid, and further, a top sheet strip that becomes the top sheet 3 and a side sheet that becomes the side sheet 7 are overlaid, and heat sealing or the like is performed on a predetermined portion and then cut. The adhesive Ad1 joins the absorber part 4 and the back sheet 2 vertically, but at the position where there is no absorber part 4, it joins the top sheet 3 or the side sheet 7 and the back sheet 2. In addition, in the backsheet band 2A, an adhesive Ad2 (hatched) may be continuously applied along the conveyance direction Dt at the planned positions for forming the wings W, W. By disposing the side sheet 7 on the adhesive Ad2, the backsheet 2 and the side sheet 7 are joined at both side portions of the absorbent article 1 to form the wings W, W.

[0095] <Modification example of side sheet> Furthermore, a modification example of the side sheet 7 in the absorbent article 1 will be described. The basic configuration of the absorbent article 1 shown in FIG. 7 is the same as the form shown in FIG. 1, but the side sheets 7, 7 are not overlapped on the topsheet 3, but are arranged on the lower side (non-skin side) of the absorbent body portion 4, which is different from the form shown in FIG. 1.

[0096] The closer the absorbent body portion 4 and the backsheet 2 are in contact with each other, the more difficult it is for the absorbent body portion 4 and the backsheet 2 to slide relative to each other. However, according to this modification example, at both end portions in the width direction D2, the side sheets 7, 7 are respectively sandwiched between the absorbent body portion 4 and the backsheet 2, so that it becomes difficult for the absorbent body portion 4 and the backsheet 2 to be in close contact with each other. Therefore, the absorbent body portion 4 and the backsheet 2 are more easily movable relative to each other, so that the structure from the absorbent body portion 4 to the top surface follows the skin more easily, and the backsheet 2 (when a member is disposed under the backsheet 2, the structure from the backsheet 2 to the bottom surface) follows the underwear more easily. And the effect of preventing rubbing as described above is improved.

[0097] In the example shown in FIG. 7, the side sheets 7, 7 are each folded back downward inside the width direction D2. The side sheet 7 does not have to be folded back, but by folding it back, the side sheet 7 sandwiched between the absorbent body portion 4 and the backsheet 2 becomes two layers, so that the absorbent body portion 4 and the backsheet 2 are more easily movable relative to each other.

[0098] FIG. 8 shows another modification of the side sheet 7. The basic configuration of the absorbent article 1 shown in FIG. 8 is also the same as the form shown in FIG. 1. In the example shown in FIG. 7, similar to the example shown in FIG. 7, the side sheets 7, 7 are arranged on the lower side (non-skin side) of the absorbent body portion 4. Further, each of the side sheets 7, 7 is folded back inside in the width direction D2 on the upper side (skin side), and extends outward in the width direction D2 beyond the width of the absorbent body portion 4. Such side sheets 7, 7 can be used for forming gathers.

[0099] The absorbent article 1 described above was a product with wings, but even in a product without wings, the same effects can be obtained by the above-described configuration. However, in the case of a product with wings, since the back sheet 2 can be firmly fixed to the underwear, preferential sliding is likely to occur between the absorbent body portion 4 and the back sheet 2, so the effect of preventing rubbing is enhanced.

[0100] <Another Embodiment (Absorbent Article Having a Fixing Portion in the Rear Region)> FIG. 9 shows a plan view of the absorbent article 11 according to another embodiment of the present disclosure as viewed from the side facing the skin (skin side) during wearing. Further, FIG. 10 shows a cross-sectional view taken along line III-III of FIG. 9, and FIG. 11 shows a cross-sectional view taken along line IV-IV of FIG. 9. The absorbent article 11 according to the present embodiment is different from the absorbent article 1 shown in FIGS. 1 and 2 in that the range in which the fixing portion 8 is formed, and thus the range of the slippery region NB, is different. More specifically, in the absorbent article 11, at least the front region Ef and the central region C are the slippery regions NB. Further, the slippery region NB is also provided in a part of the rear region Eb. And the slippery region NB continuously extends from the front end of the absorbent body portion 4 to a position beyond the boundary between the central region C and the rear region Eb as shown in FIG. 9. In the absorbent article 11 according to the present embodiment, among the fixing portions 8, the fixing portion where the absorbent body portion 4 and the back sheet 2 are fixed in the rear region Eb is called the first fixing portion 81, and the fixing portion where the absorbent body portion 4 and the back sheet 2 are fixed in the front region Ef is called the second fixing portion 82.

[0101] FIG. 9 also shows a squeezing groove (fit emboss) EM that is provided in the absorbent article body and that is recessed from the topsheet 3 side toward the backsheet 2 side by a method known in the art. The squeezing groove EM has a function of appropriately guiding the body fluid discharged to the skin side of the absorbent article 11 and promoting the deformation of the absorbent article 1 along the shape of the body. Further, due to the presence of the squeezing groove EM, the topsheet 3 and the absorbent body portion 4, or the topsheet 3, the intermediate sheet 5, and the absorbent body portion 4 are joined vertically, so that they can be deformed and move integrally even when a force is applied.

[0102] As described above in the description of the absorbent article 1, the slippery region NB is an excellent anti-slip mechanism. Therefore, from the viewpoint of improving the anti-slip effect, it is preferably provided over a wide range. However, some wearers may feel that the absorbent article floats from the underwear and is not stably worn, for example, near the buttocks. This is presumably because the buttocks, which are at the back of the body, move relatively greatly, the absorbent article somewhat enters the groove of the buttocks, and the area where the topsheet is in close contact is large, so that the structure from the absorbent body portion 4 to the uppermost surface and the topsheet 3 below it are likely to separate vertically. Further, the feeling that the absorbent article floats and is not stable as described above may also be felt in the front region Ef. Such a floating feeling may cause discomfort during wearing and may impair the comfortable wearing feeling.

[0103] In contrast, in the present embodiment, a fixing portion 8 in which the absorber portion 4 and the back sheet are fixed in the thickness direction is formed in at least one of the front region Ef and the rear region Eb. Therefore, in at least one of the front region Ef and the rear region Eb, an undesirable relative movement between the absorber portion 4 and the back sheet 2 can be suppressed. For example, as shown in FIGS. 9 to 11, a first fixing portion 81, which is a portion where the absorber portion 4 and the back sheet 2 are fixed, is formed in the rear region Eb. In that case, even when the buttocks move while being in close contact with the absorbent article 11, the rear region Eb moves integrally up and down at that time, so that a feeling that the structure above the absorber portion 4 floats from the back sheet 2 and the underwear is avoided. Also, since the central region C is often the region where rubbing is easily felt, if a rubbing prevention mechanism can be ensured in the central region C, the wearer can more strongly feel the effect of rubbing prevention. In this way, according to the present embodiment, while maintaining the effect of rubbing prevention, the discomfort that may be caused by providing the rubbing prevention mechanism can also be reduced, and a comfortable wearing feeling can be obtained. Further, due to the presence of the fixing portion, the shape stability of the absorbent article 11 can also be improved. That is, an advantage is obtained in that the absorbent article 11 is less likely to break when the wearer moves violently or when force is applied during replacement of the absorbent article 11.

[0104] In the drawings, the range of the fixing portion where the absorber portion 4 and the back sheet 2 are fixed is indicated by a matte pattern (fine dots). As shown in FIG. 9, the first fixing portion 81 is provided in a continuous band shape over the longitudinal direction D1. The first fixing portion 81 is composed of a plurality of annular adhesive application portions (dotted lines) that are shifted and overlapped in the longitudinal direction D1. The adhesive application portion may be formed of an adhesive such as hot melt, for example. That is, the fixing portion 8 (including the first fixing portion 81 and the second fixing portion 82 described later) may be a layer of adhesive. At the position where the fixing portion 8 is formed, the relative movement of the absorber portion 4 and the back sheet 2 in the plane direction is suppressed and they are fixed.

[0105] Here, in the circular adhesive application part, the adhesive is applied on the circumference of the circle, and no adhesive is applied inside the circle. Since no adhesive is applied in the inner region of the circle, the absorber part 4 and the backsheet 2 are not joined inside the circle. However, since they are surrounded by the circular adhesive application part, the absorber part 4 and the backsheet 2 are fixed, and thus are included in the fixing part 8. Note that as the fixing part 8, instead of the circular adhesive application part, an adhesive application part where the adhesive is applied in a solid circular shape may be provided.

[0106] In the form shown in FIG. 9, the first fixing part 81 in the rear region Eb extends in a strip shape on both sides of the longitudinal center line CL. However, if the absorber part 4 and the backsheet 2 in the rear region Eb can be fixed, the size, shape, and arrangement of the first fixing part 81 are not particularly limited. For example, the first fixing part 81 may be formed in a discontinuous strip shape. Also, it may be formed in one strip shape or three or more strip shapes. Further, the first fixing part 81 may not be formed by a circular or circular adhesive application part, but may be formed in a strip shape with a constant width (length in the width direction D2). Furthermore, there may be a form in which the entire region of the absorber part 4 in the rear region Eb serves as the fixing part.

[0107] Also, in the form shown in FIG. 9, the first fixing part 81 is formed in the central region m in the width direction of the absorber part 4. More specifically, it is formed on the boundary between the central region m in the width direction of the absorber part 4 and the end region s in the width direction. From the viewpoint of improving the effect of suppressing the uncomfortable feeling that the upper structure of the absorbent article 11 floats, as shown in FIG. 9, it is preferable that the first fixing part 81 is formed in the central region m in the width direction. The region in the width direction D2 of the absorber part 4 is a section obtained by dividing the length in the width direction D2 of the absorber part 4 into three equal parts. The central region is called the central region m in the width direction, and the regions on both sides of the central region m in the width direction are called the end regions s, s in the width direction, respectively.

[0108] The range in the longitudinal direction D1 where the first fixing part 81 is provided may be preferably 50% or more, preferably 75% or more of the length in the longitudinal direction D1 of the absorber part 4 in the rear region Eb. From the viewpoint of suppressing the discomfort in the rear region Eb, it is preferable that the first fixing part 81 is provided over the entire length in the longitudinal direction D1 of the absorber part 4 in the rear region Eb. Note that the first fixing part 81 may be formed within the rear region Eb or may be formed across the boundary line between the rear region Eb and the central region C. However, the first fixing part 81 is formed at a distance from the body fluid discharge port facing part Q.

[0109] The total area in plan view of the fixing parts where the absorber part 4 and the back sheet 2 are fixed in the thickness direction may be preferably 5% or more and less than 50%, more preferably less than 30% with respect to the total area of the overlapping region of the absorber part 4 and the back sheet 2. By having the area in the above ratio, the above-described effect of reducing the discomfort in at least one of the front region Ef and the rear region Eb can be improved, and the effect of preventing rubbing by the slippery region NB is not hindered.

[0110] Also, when the first fixing part 81 in the rear region Eb is formed in a strip shape along the longitudinal direction D1, the total width (length in the width direction D2) of the first fixing part 81 may be preferably 10% or more and 80% or less, more preferably 20% or more and 70% or less of the width of the absorber part 4. By having the above ratio, the above-described effect of reducing the discomfort in the rear region Eb can be improved, and it is possible to prevent the range of the fixing part from becoming excessively large and the amount of the adhesive used for the fixing part from increasing to make the absorbent article 11 hard.

[0111] <Modification example> FIG. 12 shows a plan view of the absorbent article 11A according to the modification example as viewed from the skin side. Further, FIG. 13 shows a cross-sectional view taken along line III-III of FIG. 12. The absorbent article 11 shown in FIGS. 12 and 13 has the same basic configuration as the form shown in FIGS. 9 to 11, but is different from the form shown in FIGS. 9 to 11 in that the arrangement of the fixing parts is different. In the absorbent article 11A, the first fixing parts 81, 81 are respectively provided in the width direction end regions s, s and are not provided in the width direction central region m.

[0112] During the wearing of the absorbent article, due to the movement of the wearer, the absorber portion 4 and the back sheet 2 slide relative to each other in the slippery region NB. However, such sliding behavior is somewhat restricted by the first fixing portion 81 in the rear region Eb. In particular, when the movement of the wearer is large and the sliding behavior becomes large, if the first fixing portion 81 is in the central region m in the width direction of the rear region Eb, it is likely to be restricted in movement. On the other hand, in the absorbent article 11A, since the first fixing portion 81 is not provided in the central region m in the width direction, the restriction on the relative movement between the absorber portion 4 and the back sheet 2 in the slippery region NB by the first fixing portion 81 is small, and the effect of preventing rubbing by the slippery region NB can be improved. The function of the fixing portion to reduce the feeling that a part of the absorbent article floats behind the body is ensured by the first fixing portions 81, 81 provided in the width direction end regions s, s, respectively.

[0113] From the viewpoint of reducing the restriction on the relative movement between the absorber portion 4 and the back sheet 2 in the slippery region NB, it is preferable that the first fixing portions 81, 81 are provided along the edges in the width direction D2 of the absorber portion 4 as shown in FIG. 12.

[0114] In addition, when fixing portions (second fixing portions 82, to be described later) are formed in the front region Ef, similar effects can be obtained by the arrangement in the central region m in the width direction.

[0115] FIG. 14 shows a plan view of an absorbent article 11B according to another modification as seen from the skin side. The absorbent article 11B is obtained by adding second fixing portions 82, 82 to the front of the configuration of the absorbent article 11 (FIGS. 9 to 11). That is, in the absorbent article 11B, fixing portions for fixing the absorber portion 4 and the back sheet 2 vertically are formed in the front and rear, respectively. The second fixing portions 82, 82 are also continuous strip-shaped fixing portions along the longitudinal direction D1 provided on both sides of the longitudinal center line CL, respectively. Also, similar to the first fixing portion 81, the second fixing portion 82 is formed by overlapping a plurality of annular adhesive application portions shifted in the longitudinal direction D1.

[0116] In the absorbent article 11B, in the front region Ef, the absorber portion 4 and the back sheet 2 are fixed by the second fixing portion 82, so that the shape stability in the front region Ef is obtained. That is, even when used for a long time or when the wearer moves violently during wearing, the absorber portion 4 and the back sheet 2 are difficult to separate, and the absorbent article 11B is difficult to break.

[0117] Note that the portion facing the front region Ef, that is, the front of the body, does not move as violently as the back of the body. Therefore, as shown in FIG. 14, the second fixing portion 82 may be shorter in the longitudinal direction D1 than the first fixing portion 81.

[0118] <Relationship between the displacement prevention material and the fixing portion> FIG. 15 shows a plan view of the absorbent article 11 as viewed from the non-skin side, that is, the back sheet 2 side. In FIG. 15, the displacement prevention material 9 (hatched portion) provided on the non-skin side of the absorbent article 11 is also shown. In the form shown in FIG. 15, a plurality of strip-shaped displacement prevention materials 9 are provided at intervals along the longitudinal direction D1, but the arrangement of the displacement prevention materials 9 is not limited to that shown in the figure, and may be a known arrangement of the displacement prevention materials 9.

[0119] The misalignment prevention material 9 is preferably adhesive. As the material used as the adhesive misalignment prevention material 9, known adhesives, for example, hot melt type adhesives can be used. As its main components, styrene polymers, tackifiers, plasticizers, and combinations thereof can be mentioned. Examples of styrene polymers include styrene-ethylene-butylene-styrene block copolymers, styrene-butylene-styrene block copolymers, styrene-isobutylene-styrene copolymers, styrene-butadiene-styrene block copolymers, etc., and one or more of these can be used. Also, as the tackifier and plasticizer, those that are solid at normal temperature can be used. Examples of tackifiers include C5 petroleum resins, C9 petroleum resins, dicyclopentadiene petroleum resins, rosin petroleum resins, polyterpene resins, terpene phenol resins, etc. Examples of plasticizers include monomer plasticizers such as tricresyl phosphate, dibutyl phthalate, dioctyl phthalate, etc., and polymer plasticizers such as vinyl polymers and polyesters.

[0120] With the adhesive misalignment prevention material 9, the absorbent article 11 can be surely fixed to the underwear, and during wearing, the absorbent article 11 can be prevented from shifting from the underwear. When removing the absorbent article 11 from the underwear during replacement of the absorbent article 11, the absorbent article 11 is pulled and a force is applied. Here, in the absorbent article 11 according to the present embodiment, since there is a slippery region NB where the absorbent body portion 4 and the back sheet 2 are not joined, when the absorbent article 11 is pulled to remove it from the underwear, the pulling force acts to separate between the absorbent body portion 4 and the back sheet 2 fixed to the underwear by the misalignment prevention material 9, and there is a possibility that the absorbent article 11 may be damaged. Also, when replacing the absorbent article 11, the wearer usually holds the front of the absorbent article 11 and peels it off from the front to the back. Particularly at the stage of peeling in the rear region, the pulling direction tends to become unstable, and separation between the absorbent body portion 4 and the back sheet 2 easily occurs.

[0121] In contrast, in the present embodiment, as shown in FIG. 15, in a plan view, when viewed in the longitudinal direction D1, the first fixing portion 81 overlaps the displacement preventing material 9. Therefore, when removing the absorbent article 11 from the underwear, the absorbent body portion 4 and the back sheet 2 can be integrally lifted particularly at the position where the displacement preventing material 9 is peeled off from the underwear in the rear region Eb. Thus, the possibility that the absorbent body portion 4 and the back sheet 2 are separated and the absorbent article 11 is damaged can be reduced.

[0122] The length d of the longitudinal direction D1 in which the displacement preventing material 9 and the first fixing portion 81 overlap in the longitudinal direction D1 may be preferably 5% or more and 30% or less, more preferably 10% or more and 20% or less of the length of the displacement preventing material 9 in the longitudinal direction D1. When the length d is within the above range, when peeling off the rear region Eb of the absorbent article 11 from the underwear, it becomes easier to integrally lift the components of the absorbent article 11, and it is possible to avoid preventing the function of the slippery region NB due to the fixing portion becoming excessively long.

[0123] The displacement preventing material 9 and the first fixing portion 81 do not necessarily have to overlap in a plan view as long as they overlap in the longitudinal direction D1. However, it is preferable that the displacement preventing material 9 and the first fixing portion 81 overlap in a plan view because the possibility that the absorbent body portion 4 and the back sheet 2 are separated when removing the absorbent article 11 from the underwear can be further reduced.

[0124] Also, when the second fixing portion 82 is provided in the front region Ef, if the displacement preventing material 9 overlaps the second fixing portion 82 in the longitudinal direction D1 in the front, the same effect as that described above for the first fixing portion 81 can be obtained.

[0125] In addition, the technology of the present disclosure is applicable not only to sanitary napkins, pantiliners, incontinence pads, etc., but also to diapers, and is particularly suitable as a sanitary napkin. Since sanitary napkins are often used with the skin side in close contact locally, rubbing is likely to occur between the absorbent article and the skin due to the movement of the wearer compared to other absorbent articles. Therefore, by using the embodiment of the present disclosure for sanitary napkins, rubbing between the absorbent article and the skin can be reduced, and a decrease in the wearing feeling can be prevented. In addition, itching, pain, chafing, etc. that the wearer may feel in some cases can also be prevented.

Example

[0126] Experimental examples are shown below. Note that Examples 2 to 8 (the change rate of the thickness of the wrapping sheet is less than 30%) of this experimental example were examples, and Example 1 (the change rate of the thickness of the wrapping sheet is 30% or less) was a comparative example.

[0127] <Preparation of Absorbent Article> As the absorbent articles of Examples 1 to 7, in the structure of a commercially available conventional product P (manufactured by Daio Paper Corporation, 23 cm with wings, having the arrangement of the fixing part as shown in FIG. 3), the material of the wrapping sheet of the absorbent body part was changed, and the arrangement of the fixing part between the wrapping sheet and the back sheet was changed as shown in FIG. 1. The back sheet included in the absorbent article was made of polyethylene resin, had a sheet basis weight of 25 gsm, and was non-breathable. In the conventional product P, as shown in FIGS. 3 and 4, the wrapping sheet and the back sheet were continuously fixed in the longitudinal direction. The wrapping sheet used in the conventional product P was crepe paper (sheet basis weight 15 gsm).

[0128] The materials of the wrapping sheets used in each example were as follows. Example 1: Softened spunbond nonwoven fabric (sheet basis weight 15 gsm) Example 2: Spunbond nonwoven fabric (sheet basis weight 15 gsm) Example 3: Crepe paper (sheet basis weight 15 gsm) Example 4: Air-through nonwoven fabric (sheet basis weight 18 gsm, fiber fineness 3.3 dtex) Example 5: Air-through nonwoven fabric (sheet basis weight 35 gsm, fiber fineness 5.6 dtex) Examples 6 and 7: Air-through nonwoven fabric (sheet basis weight 18 gsm, fiber fineness 5.6 dtex) In Examples 1 to 6, the above-mentioned wrapping sheet was used without treatment. On the other hand, in Example 7, a wrapping sheet having a silicone treatment with a basis weight of 5 g / cm 2 was used on the surface of the wrapping sheet facing the back sheet.

[0129] Furthermore, as Example 8, in the structure of a commercially available conventional product Pa (manufactured by Daio Paper Corporation, 36 cm with wings) having a different shape from the above-mentioned conventional product P, the material of the wrapping sheet of the absorber part was changed to an air-through nonwoven fabric (sheet basis weight 18 gsm, fiber fineness 5.6 dtex), and the fixing part 8 was formed in the regions indicated by the embossed pattern in each of the front region and the rear region as shown in Fig. 16. The wrapping sheet used in the conventional product Pa was also crepe paper (sheet basis weight 15 gsm).

[0130] <Measurement> (Coefficient of kinetic friction μ'1 between the skin and the absorbent article) The coefficient of kinetic friction was measured using a speed-variable friction measuring device (Trinity Lab Co., Ltd., μv1000). An artificial skin piece was used as a substitute for human skin. = Preparation of artificial skin piece = The artificial skin piece was prepared as follows. The main agent and the curing agent of the urethane resin were mixed at a mass ratio of 3:1, molded, and naturally polymerized and cured at room temperature. The obtained artificial skin piece 55 had a predetermined shape (length a = 97 mm × width b = 50 mm × minimum thickness t = 12 mm, spherical shape with a curvature radius of 150 mm on the lower side and convex on the lower side) as shown in Fig. 5(b), and the Asker C hardness was 15.

[0131] The absorbent article was affixed to the gold cloth with the topsheet facing upward. Further, the gold cloth was affixed to the stage of the friction tester such that the longitudinal direction of the absorbent article became the sliding direction (the sliding direction of the friction test piece). The gold cloth was used to simulate the situation where the absorbent article was affixed to underwear. Then, the artificial skin piece was placed at the center in the width direction in the central region of the absorbent article with the length direction of the artificial skin piece along the longitudinal direction of the absorbent article. In the measurement unit sliding mode, with a vertical load of 9.8 N (average contact pressure 2.4 kPa), a sliding speed of 5.3 mm / second, and a sliding distance of 15 mm one-way, the artificial skin piece was relatively slid in the longitudinal direction of the absorbent article for measurement. The movement path of the artificial skin piece was along the center line along the longitudinal direction and included the portion facing the body fluid discharge port.

[0132] (Coefficient of kinetic friction μ'2 between the absorbent body part and the backsheet) The coefficient of kinetic friction between the absorbent body part and the backsheet was measured using a multi-functional static and kinetic friction measuring device (Trinity Lab Co., Ltd., TL201Tt). Specifically, the covering sheet and the backsheet portions were taken out from the absorbent articles of each example, the central portion in the width direction in the central region of the backsheet was attached to a 2 cm × 2 cm contactor, the covering sheet was fixed to the measurement table, and measurement was performed in the table sliding mode under the conditions of a weight of 10 g, a sliding speed of 10 mm / second, and a sliding distance of 50 mm one-way.

[0133] (Comparison of the maximum value of shear strain of the artificial skin piece: comparison between Example 6 and the conventional product P) The shear strain generated in the artificial skin piece was measured using the above friction testing apparatus (Trinity Lab Co., Ltd., μv1000). First, as shown in Fig. 5(a), the absorbent article 1 was attached to the gold cloth 52 with the topsheet facing upward. Further, the gold cloth 52 was attached to the stage 51 of the friction testing apparatus so that the longitudinal direction of the absorbent article 1 was the sliding direction (the sliding direction of the friction test piece). The gold cloth 52 was used to simulate the situation where the absorbent article was attached to the underwear. Then, the artificial skin piece 55 was placed at the center in the width direction in the slippery region of the absorbent article, more specifically, in the central region. Under the conditions of a vertical load of 9.8 N (average contact pressure of 2.4 kPa), a slide speed of 5.3 mm / s, and a slide distance of 15 mm, the stage 51 was moved in one direction so that the artificial skin piece 55 and the absorbent article 1 slid relative to each other. The slide direction Ds of the stage 51 was the longitudinal direction of the absorbent article 1.

[0134] The analysis of the shear strain generated in the artificial skin piece was performed by the digital image correlation method (DICM). More specifically, a random dot pattern (speckle pattern) was sprayed with paint on the side surface (end face in the width direction) of the artificial skin piece, and the side surface was photographed over time with a high-speed camera. The 28 mm × 13 mm analysis region of the photographed side surface image was divided into 2100 grids, and the position change of each grid point was calculated by analyzing the luminance value distribution of each divided section, and the shear strain distribution at each time was obtained. Further, the temporal change of the maximum value of the shear strain of the artificial skin piece (the maximum value of the absolute value of the shear strain value within the analysis region) was obtained. Further, the value that became the maximum in the temporal change over the measurement time was recorded as the representative value of the maximum value of the shear strain.

[0135] (Comparison of the maximum shear strain of the artificial skin piece: comparison between the slippery region and the fixed part in Example 8) For the absorbent article of Example 8 (Fig. 16), the maximum value τ of the shear strain of the artificial skin piece at the center in the longitudinal direction D1 and the center in the width direction D2 of the fixed part 8 in the rear region B was measured at the center in the longitudinal direction D1 and the center in the width direction D2 of the slippery region NB in the same manner as described above for the maximum value τ N of the shear strain of the artificial skin piece.

[0136] (Compression work amount) The compression work amount (WC value) in the thickness direction of the wrapped sheet was measured using a KES compression tester (manufactured by Kato Tech Co., Ltd., KES-G5). In the measurement, a steel pressure plate with a pressure area of 2 cm 2 was used, and the measurement was carried out under the conditions of a load of 10 gf / cm 2 and a speed of 0.02 mm / sec.

[0137] (Thickness change rate) In the measurement of the above compression work amount, the thickness of the wrapped sheet before and after compression was measured, and further the thickness change rate R (%) was measured. Note that, taking the thickness before compression as T1 and the thickness after compression as T2, R (%) = (T1 - T2) / T1 × 100.

[0138] In any of the measurements, the same measurement was carried out 5 times, and the average value was taken as the measurement result.

[0139] (Sensory evaluation) (Evaluation I: Comparison of rubbing with the skin) The subjects were asked to wear the absorbent article in the normal way and then walk at the normal speed. Then, they were asked to evaluate the rubbing between the absorbent article and the skin felt during walking. The evaluation was carried out in comparison with the conventional product P. Note that the conventional product P has the same basic configuration as the absorbent articles in Examples 1 to 6, but is an absorbent article in which the absorbent body part and the back sheet are continuously joined in the longitudinal direction as shown in FIGS. 3 and 4. The criteria for Evaluation I were as follows. A: The rubbing was significantly reduced compared to the conventional product P B: A significant reduction in rubbing was felt compared to the conventional product P C: A reduction in rubbing was felt compared to the conventional product P D: A slight reduction in rubbing was felt compared to the conventional product P E: The feeling of rubbing was the same as that of the conventional product P.

[0140] (Evaluation II: Satisfaction regarding lack of rubbing) Sixteen subjects were each asked to use the absorbent article of Example 6 and the conventional product P in a normal manner. Then, regarding the "satisfaction with non-abrasion", they were asked to answer with one of "satisfied with the absorbent article of Example 6", "can't say either way", or "satisfied with the conventional product P". For all the subjects, the percentage of the number of subjects who answered "satisfied with the absorbent article of Example 6" and the percentage of the number of subjects who answered "satisfied with the conventional product P" were each recorded.

[0141] Table 1 shows the measurement results of the dynamic friction coefficients μ'1 and μ'2 for the absorbent article of Example 6.

[0142]

Table 1

[0143] Furthermore, Table 2 shows the results of Measurement and Evaluation I for the absorbent articles of Examples 1 to 7.

[0144]

Table 2

[0145] As shown in Table 1, for the absorbent article according to the embodiment of the present disclosure, the dynamic friction coefficient μ'2 between the absorbent body part and the back sheet was smaller than the dynamic friction coefficient μ'1 between the skin and the absorbent article. Regarding such an absorbent article, an evaluation regarding the rubbing suppression effect was recognized (Table 2).

[0146] Also, as shown in Table 2, for any of Examples 1 to 7, a rubbing suppression effect was recognized as compared with the conventional product P. Among them, the absorbent articles provided with an air-through nonwoven fabric as the covering sheet (Examples 4 to 6), and the absorbent articles provided with a covering sheet obtained by further subjecting the air-through nonwoven fabric to a silicone treatment (Example 7) had a remarkable rubbing suppression effect.

[0147] Table 3 shows the comparison of the maximum shear strain of the artificial skin pieces between the absorbent article of Example 6 and the conventional product P, and the results of Evaluation II.

[0148] [Table 3]

[0149] As shown in Table 3, it was found that the absorbent article having the relationship of τ < τc has a higher evaluation regarding the satisfaction of rubbing than the conventional product.

[0150] Table 4 shows the comparison results of the maximum shear strain τ B of the artificial skin piece in the fixing part and the maximum shear strain τ N of the artificial skin piece in the slippery region in the absorbent article of Example 8.

[0151] [Table 4]

[0152] As shown in Table 4, in the absorbent article of Example 8, the maximum shear strain τ N of the artificial skin piece in the slippery region was smaller than the maximum shear strain τ B of the artificial skin piece in the fixing part.

[0153] As described above, the present disclosure has been described based on the embodiments, but the present disclosure is not limited by these embodiments. Within the scope described in the claims, various changes, modifications, substitutions, additions, deletions, combinations, etc. are possible, and these also belong to the technical scope of the present disclosure. Also, the above-described components can be arbitrarily combined. [Description of Reference Numerals]

[0154] 1 Absorbent article 1' Absorbent article (prior art) 2 Backsheet 2A Backsheet band 3 Topsheet 4 Absorbent body part 4a Absorbent body main body 4b Wrapped sheet 5 Intermediate sheet 7 Side sheet 8 Fixing part 9 Displacement preventing material 81 First fixing part 82 Second fixing part C Central region CL Longitudinal center line D1 First direction (longitudinal direction) D2 Second direction (width direction) Dt Conveying direction Ef Front region Eb Rear region EM Squeezing groove NB Anti-slip region Q Region facing the body fluid discharge port W Wing

Claims

Claim 1 An elongated absorbent article in which a liquid-impermeable backsheet, an absorber portion, and a liquid-permeable topsheet are laminated in this order, wherein the absorber portion includes an absorber body and a wrapping sheet that wraps the absorber body, and the wrapping sheet is disposed directly on the backsheet, the absorber portion and the backsheet have a slippery region that is not fixed in the thickness direction, with the coefficient of kinetic friction between the wearer's skin and the absorbent article being μ'1 and the coefficient of kinetic friction between the absorber portion and the backsheet being μ'2, μ'1 > μ'2, The thickness change rate of the wrapped sheet before and after the application of a load of 10 gf / cm ２ is 30% or more, an absorbent article. Claim 2 The absorbent article according to claim 1, wherein the ratio of the coefficient of kinetic friction μ'2 between the absorber portion and the backsheet to the coefficient of kinetic friction μ'1 between the wearer's skin and the absorbent article is 95% or less. Claim 3 including a central region including a body fluid discharge port facing portion facing the wearer's body fluid discharge port, a front region in front of the central region, and a rear region behind the central region, wherein at least the central region is the slippery region, the absorbent article according to claim 1 or 2. Claim 4 The absorbent article according to claim 1 or 2, wherein the slippery region is formed across the entire width direction of the absorbent article. Claim 5 The absorbent article according to claim 1 or 2, wherein the coefficient of kinetic friction between the absorber portion and the backsheet is 0.8 or less. Claim 6 The absorbent article according to claim 1 or 2, wherein the area of the slippery region is 50% or more of the area of the overlapping region between the absorber portion and the backsheet. Claim 7 The absorbent article according to claim 1 or 2, wherein the wrapping sheet includes an air-through nonwoven fabric. Claim 8 The amount of compression work measured by a compression testing machine of the sheet to be wrapped is 0.10 gf·cm / cm ２ The absorbent article according to claim 7, wherein the amount is 0.10 gf·cm / cm or more. Claim 9 the absorber portion and the backsheet have a fixed portion fixed in the thickness direction, Let τ be the maximum value of the shear strain of the artificial skin piece measured by rubbing the artificial skin piece under a load in the thickness direction in the slippery region. Ｎ Let τ be the maximum value of the shear strain measured under the same conditions as the measurement of τ in the fixing part. Ｎ Let τ be the maximum value of the shear strain measured under the same conditions as the measurement of τ. Ｂ If τ Ｎ <τ Ｂ The absorbent article according to claim 1 or 2. Claim 10 including a central region including a body fluid discharge port facing portion facing the wearer's body fluid discharge port during wearing, a front region in front of the central region, and a rear region behind the central region, the absorber portion and the backsheet have a fixed portion fixed in the thickness direction, the ratio of the area of the fixed portion to the entire area of the overlapping region between the absorber portion and the backsheet is less than 50%, the absorbent article according to claim 1 or 2, wherein the fixed portion is provided in at least one of the front region and the rear region.

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