Absorbent article

Abstract

This absorbent article comprises a liquid-impermeable back sheet and a skin-side structure part disposed on the skin side of the back sheet. The skin-side structure part includes an absorber part disposed directly on the skin side of the back sheet, and a liquid-permeable top sheet disposed on the skin side of the absorber part. The absorbent article has: a non-fixed region in which the back sheet and the skin-side structure part are not fixed to each other, and the back sheet and the skin-side structure part can slide relative to each other; and a fixed region other than the non-fixed region. In the non-fixed region, the average deviation of the dynamic friction coefficient of the surface of the non-skin side of the back sheet is less than that in the fixed region.

Description

Absorbent article

[0001] The present disclosure relates to absorbent articles.

[0002] Conventionally, as absorbent articles such as sanitary napkins, panty liners, incontinence pads, etc., those having a liquid-impermeable backsheet, an absorbent body part, and a liquid-permeable topsheet in this order are known. Since absorbent articles are worn while being 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 and improving the wearing feeling, for example, it is known to use a topsheet with unevenness (for example, Patent Document 1). Also, absorbent articles in which a drug such as a skin care agent is applied to the skin side of the topsheet are known (for example, Patent Document 2).

[0004] Japanese Patent Application Laid-Open No. 2017-55841, Japanese Patent Application Laid-Open No. 2023-19296

[0005] The technologies disclosed in Patent Documents 1 and 2 are those that devise the members that directly contact the skin. Such technologies can reduce the damage when the skin side surface of the absorbent article rubs against the skin, but do not improve the wearing feeling by preventing the rubbing itself. Therefore, there is a need for a configuration that allows the skin side surface of the absorbent article to follow the skin as much as possible, suppresses rubbing, and improves the wearing feeling.

[0006] Also, in conventional absorbent articles, usually, the backsheet and the absorbent body part are fixed as a whole (for example, refer to FIGS. 4 and 5). Therefore, the influence of the means for fixing (for example, an adhesive) appears in the state of the backsheet, and a state where wrinkles occur on the non-skin side of the backsheet may be observed. Although it is less likely for the non-skin side of the absorbent article to be seen compared to the skin side, it may damage the impression of the absorbent article when the user takes a quick glance.

[0007] In view of the above points, one aspect of the present disclosure is to provide a technique that improves the wearing feeling by allowing the skin side surface of the absorbent article to follow the wearer's skin well and can prevent wrinkles on the non-skin side of the absorbent article.

[0008] One aspect of the present disclosure is an absorbent article having an impermeable backsheet and a skin-side structure disposed on the skin side of the backsheet, wherein the skin-side structure includes an absorbent portion directly disposed on the skin side of the backsheet and a permeable topsheet disposed on the skin side of the absorbent portion, and the backsheet and the skin-side structure are not fixed, and the article has a non-fixed region in which the backsheet and the skin-side structure are relatively slidable, and a fixed region other than the non-fixed region, wherein the average deviation of the coefficient of dynamic friction of the non-skin side surface of the backsheet in the non-fixed region is smaller than the average deviation of the coefficient of dynamic friction of the non-skin side surface of the backsheet in the fixed region.

[0009] According to one aspect of this disclosure, a technology is available that improves the wearing comfort by enabling the skin-facing surface of an absorbent article to conform well to the wearer's skin, and also prevents wrinkles on the non-skin side of the absorbent article.

[0010] This is a plan view of an absorbent article according to one embodiment of the present disclosure, as seen from the skin side. This is a cross-sectional view taken along line I-I in Figure 1. This is a cross-sectional view taken along line II-II in Figure 1. This is a plan view of an absorbent article according to the prior art, as seen from the skin side. This is a cross-sectional view taken along line I'-I' in Figure 4. This is a plan view of an absorbent article according to a modified example. This is a plan view of an absorbent article according to a modified example. This is a diagram illustrating a part of the manufacturing process of an absorbent article according to one embodiment.

[0011] The embodiments of this disclosure will be described in detail below 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 their descriptions may be omitted. Also, the drawings are schematic in order to aid in understanding the invention, and some dimensions may be shown larger or smaller than they actually are. Furthermore, in cross-sectional views, two components may be shown separated to indicate that no other component is interposed between them.

[0012] The absorbent articles according to the embodiments of this disclosure may specifically be sanitary napkins, light incontinence pads, panty liners, diapers, etc., but are preferably used as sanitary napkins. In the following, this embodiment will be described based on the example of a sanitary napkin.

[0013] <Basic Structure of Absorbent Articles> Figure 1 shows a plan view of an absorbent article 1 according to one embodiment of the present disclosure, as seen from the side facing the skin when worn (skin side). Figure 2 shows a cross-sectional view taken along line I-I in Figure 1, and Figure 3 shows a cross-sectional view taken along line II-II in Figure 1. In the cross-sectional views, the gray color indicates the joining or fixing of layers. That is, the gray area in the cross-sectional view indicates that the two members sandwiching the gray area are joined or fixed to each other. Two members laminated without an intervening gray area are in direct contact or can be in direct contact, but are not joined or fixed to each other.

[0014] As shown in Figures 1 to 3, the absorbent article 1 is made up of an impermeable backsheet 2, an absorbent portion 4, and a permeable topsheet 3, which are laminated in this order from the non-skin side to the skin side. When the wearer is wearing the absorbent article 1, the backsheet 2 side (non-skin side) is fixed to underwear such as shorts by a slip-prevention portion (described in detail later), and the topsheet 3 side (skin side) is in contact with the skin. In this specification, the portion of the backsheet 2 laminated on the skin side is called the skin-side structure 15. The skin-side structure 15 is a portion that includes at least the absorbent portion 4 and the topsheet 3, and may also include an intermediate sheet, as will be described later. Alternatively, the skin-side structure 15 may be the entire portion up to the surface that comes into contact with the wearer's skin. The skin-side structure 15 is arranged such that the absorbent portion 4 is directly superimposed on (in direct contact with) the backsheet 2. However, although the absorbent portion 4 of the skin-side structure 15 is mainly in contact with the backsheet 2, other layers other than the topsheet 3, or other layers other than the absorbent portion 4 and the topsheet 3, such as the sidesheet 7, may be in contact with the backsheet 2 around the absorbent portion 4. Within the skin-side structure 15, the components may or may not be fixed to each other, but the absorbent portion 4 and the topsheet 3 may be fixed together by adhesive or embossing as shown in Figures 2 and 3.

[0015] The absorbent article 1 may be provided with wings WG, WG extending from both sides. The wings WG, WG are parts that are folded back to the non-skin side of the underwear when worn to securely fix the absorbent article 1 to the underwear. The part excluding the wings WG, WG is called the main body of the absorbent article (also called the absorbent article body) bd. The absorbent article body bd has an elongated shape with a predetermined length in the front-to-back direction D1 and a predetermined width in the lateral direction D2 perpendicular to this front-to-back direction D1. The front-to-back direction (longitudinal direction) D1 of the absorbent article 1 corresponds to the front-to-back direction of the wearer's body when worn, and the lateral direction (short direction) D2 corresponds to the left-to-right direction of the wearer's body. The width of the absorbent article body may be approximately constant, but may vary along the front-to-back direction D1. Furthermore, although the absorbent article 1 shown in Figures 1 to 3 has a shape and structure that is substantially symmetrical with respect to the center line (front-to-back center line) CL extending in the front-to-back direction, the structure of the absorbent article does not necessarily have to be symmetrical.

[0016] The portion Q facing the bodily fluid outlet shown in Figure 1 is the part that faces the wearer's bodily fluid outlet, such as the vaginal opening, when the device is worn, and is located on the center line CL in the anterior-posterior direction. The portion Q facing the bodily fluid outlet may be in the range of 10 mm to 50 mm in the anterior-posterior direction D1 and 10 mm to 30 mm in the width direction D2, but the size of the portion Q facing the bodily fluid outlet is not necessarily limited to the above range.

[0017] The absorbent article 1 has a central region C including a portion Q facing a bodily fluid drainage port, a front region F in front of the central region C, and a rear region R behind the central region C. The wings WG, WG described above may extend laterally from the central region C (outward in the lateral direction D2). The central region C may be the region corresponding to the crotch area of ​​the wearer's underwear when worn. The central region C may also be the region from one edge to the other in the anterior-posterior direction D1 of the wing WG at the position in the lateral direction D2 where the wing WG is connected to the absorbent article body bd (the base end of the wing WG).

[0018] The length (total length) of the absorbent article 1 in the front-to-back direction D1 is preferably 150 mm or more and 450 mm or less, more preferably 170 mm or more and 360 mm or less. The thickness of the portion of the absorbent article body bd containing the absorbent part 4 is measured at a location other than the area compressed in the thickness direction, and is preferably 0.3 mm or more and 30 mm or less, more preferably 1.0 mm or more and 15 mm or less. However, the absorbent article body bd may be partially bulged by bulging the absorbent part 4 in a part of the absorbent part 4, for example, the area opposite the body fluid outlet Q and the area near it, and in the center of the width direction D2 of the rear area.

[0019] One embodiment of this disclosure may be an absorbent article without wings wg, wg. In that case, assuming that wings wg, wg are formed, the region from one edge to the other in the front-rear direction D1 at the base end of the wings wg, wg in the lateral direction D2 can be defined as the central region C.

[0020] On the skin-facing side of the top sheet 3, side sheets 7, 7 are superimposed, extending in the front-to-back direction D1 along both sides of the absorbent portion 4. The side sheets 7, 7 extend to both sides and are joined to the back sheet 2, which also extends to both sides, to form wings wg, WG. The side sheets 7, 7 may extend inward in the width direction D2 to form gathers. The absorbent article 1 does not necessarily have side sheets 7, 7; in that case, the wings wg may be formed by joining the back sheet 2 and a sheet positioned on the non-skin side of the back sheet 2.

[0021] In the example shown in Figure 1, both the back sheet 2 and the top sheet 3 have the same length in the front-to-back direction D1, extending from the front end to the rear end of the absorbent article 1. On the other hand, the width of the top sheet 3 (length in the lateral direction D2) is smaller than the width of the back sheet 2. The absorbent portion 4 is provided sandwiched between the top sheet 3 and the back sheet 2 so as not to be exposed to the outside. For example, as shown in Figure 1, the absorbent portion 4 is arranged so as to fit within the back sheet 2 in a plan view, that is, so as not to protrude from the back sheet 2. The absorbent portion 4 is also configured and arranged so as to fit within the area where the top sheet 3 and side sheets 7, 7 are provided. For example, the absorbent portion 4 may protrude from the top sheet 3 at both ends in the width direction D2, but in that case, the protruding portions are covered by the side sheets 7, 7.

[0022] As the backsheet 2, a sheet material having at least water-impermeable properties, such as an olefin resin sheet of polyethylene or polypropylene, can be used. Laminated nonwoven fabrics, such as polyethylene sheets laminated with nonwoven fabric, or laminated nonwoven fabric sheets with a waterproof film interposed to ensure substantially liquid impermeability can be used. Furthermore, from the viewpoint of preventing stuffiness, it is even more desirable to use a material that has moisture permeability. As such a water-impermeable and moisture-permeable sheet material, a microporous sheet obtained by melt-kneading an inorganic filler into an olefin resin such as polyethylene or polypropylene, forming a sheet, and then stretching it in a uniaxial or biaxial direction can be used.

[0023] The top sheet 3 is a permeable sheet that allows bodily fluids such as menstrual blood, vaginal discharge, and urine to pass through quickly. Suitable materials for the top sheet 3 include perforated or non-perforated nonwoven fabrics and porous plastic sheets. Suitable materials for the nonwoven fabric include, for example, olefins such as polyethylene and polypropylene, synthetic fibers such as polyester and polyamide, regenerated fibers such as rayon and cupro, and blends thereof, as well as natural fibers such as cotton, which can be used individually or in combination of two or more. Processing methods for the nonwoven fabric include the spunlace method, spunbond method, thermal bond method, meltblown method, and needle punch method. Of these processing methods, the spunlace method is preferred for producing flexible nonwoven fabrics, the spunbond method for producing nonwoven fabrics with good drape, and the thermal bond method for producing bulky and soft nonwoven fabrics. Furthermore, composite fibers such as core-sheath type fibers, side-by-side type fibers, and split type fibers, which use fibers with high melting points as a core and fibers with low melting points as a sheath, can be used.

[0024] As the side sheet 7, a water-repellent nonwoven fabric or a hydrophilic nonwoven fabric can be used. For example, to prevent menstrual blood or vaginal discharge from penetrating or to enhance the feel against the skin, it is preferable to use a water-repellent nonwoven fabric coated with a silicone-based or paraffin-based water-repellent agent. Also, to improve the absorbency of menstrual blood, etc. in the wing wg, it is preferable to use a hydrophilic nonwoven fabric as the nonwoven fabric material. As for the type of nonwoven fabric, an air-through nonwoven fabric that is soft, does not easily crease or wrinkle, and is resistant to folding is preferred.

[0025] As shown in Figures 2 and 3, the absorbent body 4 can be configured to include an absorbent body 4a that substantially performs the function of absorbing bodily fluids, and a covering sheet 4b that encloses the absorbent body 4a.

[0026] The materials constituting the absorbent body 4a are not limited as long as they can absorb and retain bodily fluids, but it is preferable that they include cotton-like pulp and a superabsorbent polymer. As the superabsorbent polymer, superabsorbent polymer granules (SAP), superabsorbent polymer fibers (SAF), and combinations thereof can be used. As the pulp, examples include cellulose fibers such as chemical pulp and dissolved pulp obtained from wood, and artificial cellulose fibers such as rayon and acetate. Recycled pulp and recycled fibers can also be used. As raw materials for chemical pulp, hardwoods and softwoods can be used, but softwoods are preferably used because of their long fiber length. The absorbent body 4a can be manufactured by the fiber stacking or airlaid method. Furthermore, as the absorbent body 4a, a thin sheet consisting of a layer of superabsorbent polymer granules and / or superabsorbent polymer fibers sandwiched between sheets of nonwoven fabric or the like, a so-called SAP sheet, can also be used. When an SAP sheet is used, the encasing sheet 4b can be omitted.

[0027] Furthermore, synthetic fibers may be mixed into the absorbent body 4a. As 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 also be mixed and used. In addition, composite fibers such as core-sheath fibers, side-by-side fibers, and split fibers, with a high-melting-point fiber as the core and a low-melting-point fiber as the sheath, can also be used. Furthermore, hydrophobic fibers can be surface-treated with a hydrophilizing agent to impart affinity to body fluids.

[0028] The structure in which the absorbent body 4a is wrapped by the covering sheet 4b prevents the fibrous or granular material contained in the absorbent body 4a from spilling out, and also prevents the entire absorbent part 4 from becoming distorted or cracked, thus improving the shape retention of the absorbent part 4. However, the covering sheet 4b is not necessarily required.

[0029] The material of the covering sheet 4b is not particularly limited, but may be nonwoven fabric, paper, etc. As for nonwoven fabrics, air-through nonwoven fabric, spunbond nonwoven fabric, flexible spunbond nonwoven fabric, etc. are used. As for paper, crepe paper is used. When the absorbent body 4a is wrapped by the covering sheet 4b, the back sheet 2 and the covering sheet 4b will be in direct contact within the absorbent article 1. Therefore, from the viewpoint of reducing friction between the back sheet 2 and the absorbent part 4, and consequently friction between the back sheet 2 and the skin-side structure part 15 on the skin side of the back sheet 2, an air-through nonwoven fabric is preferred.

[0030] Furthermore, an intermediate sheet may be provided between the top sheet 3 and the absorbent portion 4 to facilitate the transfer and diffusion of bodily fluids that have reached the top sheet 3 toward the non-skin side and / or in the planar direction. However, the intermediate sheet 5 may be omitted. If an intermediate sheet is provided, the material of the intermediate sheet can be, for example, the same material as the top sheet 3 described above.

[0031] <Basic configuration of the anti-slip section> An anti-slip section 9b (hereinafter also referred to as the anti-slip section for the main body) is provided on the non-skin side of the back sheet 2 of the absorbent article body bd. When the absorbent article 1 is worn, the anti-slip section 9b can be attached to the underwear to prevent the absorbent article 1 from shifting away from the underwear.

[0032] The material constituting the anti-slip portion 9b is not particularly limited, as long as it can suppress the shifting of the absorbent article 1 against the underwear when it is attached to the underwear, and allows the absorbent article 1 to be easily removed from the underwear after use. The anti-slip portion 9b is preferably formed as a layer of adhesive, and it is preferable to use a hot-melt type adhesive. The main components of the anti-slip portion 9b can be a styrene polymer, a tackifier, a plasticizer, or a combination thereof.

[0033] Examples of styrene-based polymers include styrene-ethylene-butylene-styrene block copolymers, styrene-butylene-styrene block copolymers, styrene-isobutylene-styrene copolymers, and styrene-butadiene-styrene block copolymers, and one or more of these can be used. Among these, styrene-butadiene-styrene block copolymers are preferred due to their good thermal stability. In addition, tackifiers and plasticizers that are solid at room temperature can be used. Examples of tackifiers include C5 petroleum resins, C9 petroleum resins, dicyclopentadiene petroleum resins, rosin petroleum resins, polyterpene resins, and terpene phenol resins. Examples of plasticizers include monomer plasticizers such as triflethyl phosphate, dibutyl phthalate, and dioctyl phthalate, as well as polymer plasticizers such as vinyl polymers and polyesters.

[0034] The arrangement of the anti-slip portion 9b is not particularly limited; it is sufficient that the anti-slip portion 9b is provided within the range of the absorbent article body bd in a plan view, and may extend beyond the range in which the absorbent portion 4 is provided. However, it is preferable that the anti-slip portion 9b is provided within the range in which the absorbent portion 4 is provided, as this allows the body bd to be more stably fixed to the underwear. The anti-slip portion 9b may be provided over the entire range in which the absorbent portion 4 is provided, or it may be provided in part of the above range. In that case, the anti-slip portion 9b may be provided continuously or discontinuously.

[0035] For example, the anti-slip portion 9b may include a plurality of strip-shaped anti-slip portions 9b that extend along the front-to-back direction D1 and are spaced apart from each other in the lateral direction D2, as shown in Figure 1. In such a configuration, the absorbent article body bd can be continuously fixed to the underwear along the front-to-back direction D1, and if the anti-slip portion 9b is an adhesive layer, the anti-slip portion 9b can be arranged over a wide area without the adhesive force of the anti-slip portion 9b becoming excessively strong. In the example shown in Figure 1, three anti-slip portions 9b are provided along the front-to-back direction D1, but the number of anti-slip portions 9b is not limited to three; there may be one, two, or four or more. In a configuration that includes strip-shaped anti-slip portions 9b extending along the front-to-back direction D1, it is preferable to have anti-slip portions 9b that are positioned to overlap the front-to-back center line CL, as this allows the absorbent article body bd to be fixed to the underwear more stably.

[0036] Although not shown in the figures, the anti-slip portion 9b may include a plurality of strip-shaped anti-slip portions that extend along the lateral direction D2 and are spaced apart from each other in the front-rear direction D1. In such an example, the absorbent article body bd can be continuously fixed to the underwear along the lateral direction D2, and if the anti-slip portion 9b is an adhesive layer, the anti-slip portion 9b can be placed over a wide area without the adhesive force of the anti-slip portion 9b becoming excessively strong.

[0037] Furthermore, the anti-slip portion 9b may be arranged in a known form other than those described above.

[0038] A wing anti-slip portion 9w may also be provided on the non-skin side of the wing wg, that is, on the non-skin side of the backsheet 2 that constitutes the wing wg. The wing anti-slip portions 9w, 9w ensure that the wings wg, WG are securely fixed to the underwear when worn. The wing anti-slip portion 9w may also be made of the same material as the main body anti-slip portion 9b provided on the main body bd as described above.

[0039] <Fixing of Backsheet and Skin-Side Structure> In one embodiment of the present disclosure, the absorbent article 1 has an unfixed area 25 on the absorbent article body bd where the backsheet 2 and the skin-side structure 15 directly arranged on the skin side of the backsheet 2 are not fixed. First, the fixing of the backsheet 2 and the skin-side structure 15 in the conventional absorbent article will be explained with reference to Figures 4 and 5. Figure 4 is a plan view of the conventional absorbent article 1' as seen from the skin side, and Figure 5 is a cross-sectional view taken along the line I'-I' in Figure 3.

[0040] The basic structure of the conventional absorbent article 1' is the same as that of the absorbent article 1 described above. However, as shown in Figures 4 and 5, in the absorbent article 1', the back sheet 2 and the skin-side structure 15 are fixed to each other with adhesive 8 (shown in textured hatching or gray). More specifically, the back sheet 2 and the side sheet 7 are bonded together with side adhesive 8a, and in the absorbent article body bd, the back sheet 2 and the absorbent part 4 are bonded together over the entire surface (over the entire surface in the front-to-back direction D1 and the entire surface in the lateral direction D2) with body adhesive 8b. That is, in the body bd of the absorbent article 1', a fixed area 21 is formed over the entire surface of the body bd to which the back sheet 2 and the skin-side structure 15 are fixed. For this reason, in the conventional absorbent article 1', the back sheet 2 and the skin-side structure 15, which includes the absorbent part 4 and the top sheet 3, are fixed in the thickness direction, and the back sheet 2 and the skin-side structure 15 cannot slide relative to each other. Therefore, when the wearer moves their body while wearing absorbent item 1', the underwear also deforms with the movement, but the entire absorbent item 1' deforms in accordance with the deformation of the underwear. As a result, the skin-facing side of absorbent item 1' moves in a way that causes it to rub against the wearer's skin.

[0041] In contrast, as shown in Figures 1 and 2, in the absorbent article 1 according to one embodiment of the present disclosure, the absorbent article body bd has an unfixed region 25 in which the back sheet 2 and the skin-side structural part 15 directly arranged on the skin side of the back sheet 2 are not fixed. In the cross-sectional view of Figure 2, the back sheet 2 and the absorbent part 4 are shown separated, but this is shown to indicate that there is no other member (including adhesive) interposed between the back sheet 2 and the absorbent part 4, and the back sheet 2 and the absorbent part 4 are in direct contact or can be in direct contact in the thickness direction.

[0042] The non-fixed region 25 is a region in which the backsheet 2 and the skin-side structure 15 are not bonded together by adhesive means including adhesive 8 or means other than adhesive 8, and in which the backsheet 2 and the skin-side structure 15 are relatively slidable. More specifically, it includes a region in which the backsheet 2 and the absorbent portion 4 are not bonded together and are relatively slidable. Furthermore, within the non-fixed region 25, not only the absorbent portion 4 but also the top sheet 3 may be slidable relative to the backsheet 2, or layers other than the absorbent portion 4 and the top sheet 3, such as the side sheet 7, may be slidable relative to the backsheet 2. Thus, within the absorbent article 1, the backsheet 2 can move along the surface facing the skin-side structure 15, and the backsheet 2 can move along the surface facing the backsheet 2 of the skin-side structure 15. As a result, the skin-side structure 15 can follow the skin, and the backsheet 2 can follow the underwear. Therefore, regardless of the movement of the back sheet 2, the skin-side structure 15 can conform well to the wearer's skin while remaining in close contact with it (high conformability to the skin is achieved). As a result, friction between the skin and the skin-side surface of the absorbent article 1 during application is reduced, and a superior wearing comfort can be obtained that could not be achieved by simply modifying the configuration of the top sheet 3.

[0043] In the non-fixed region 25, the back sheet 2 and the skin-side structure 15 are directly laminated together, and no other material is interposed between them. Therefore, in the manufacture of the absorbent article 1 according to this embodiment, the number of materials can be reduced, and the manufacturing process can also be simplified.

[0044] In the example shown in FIG. 1, the non-fixed region 25 is formed over the entire transverse direction D2 of the absorber part 4. As a result, the entire transverse direction D2 of the absorber part 4 can slide relative to the backsheet 2, so that the followability of the skin side surface of the absorbent article 1 to the skin can be further improved. Further, the non-fixed region 25 may be formed across both ends of the absorbent article body bd in the transverse direction D2. In that case, the edge of the absorbent article body bd in the transverse direction D2 is preferably closed by applying an adhesive to the edge or performing a sealing process such as heat sealing over the entire longitudinal direction D1 in the form without the wings wg, or in the front region F and the rear region R in the form with the wings wg.

[0045] Furthermore, as shown in FIGS. 1 and 2, it is preferable that the outer end of the non-fixed region 25 in the transverse direction D2 and the outer end of the absorber part 4 in the transverse direction D2 are separated by a length k in the transverse direction D2. This separation serves as play for the absorber part 4 and makes it easier for the absorber part 4 to move relative to the backsheet 2, thus enhancing the followability of the skin side structure part 15 to the skin. The length k in the transverse direction D2 between the outer end of the non-fixed region 25 in the transverse direction D2 and the outer end of the absorber part 4 in the transverse direction D2 may preferably be 0.5 mm or more and 5 mm or less, and more preferably 1 mm or more and 3.5 mm or less.

[0046] Note that if the backsheet 2 and the skin side structure part 15 can slide relative to each other, the non-fixed region 25 does not necessarily have to be formed over the entire transverse direction D2. For example, by extending the side adhesive 8a so as to cross over the edge of the absorber part 4 in the transverse direction D2 toward the center side, the end of the absorber part 4 in the transverse direction D2 and the backsheet 2 may be adhered along the longitudinal direction D1. In that case, the length in the transverse direction D2 where the backsheet 2 and the absorber part 4 are adhered may preferably be 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less.

[0047] The non-fixed area 25 may be formed in the central area C, preferably over the entire central area C as shown in FIG. 1, and more specifically, may extend beyond the front end and the rear end of the central area C. Since the difference in the wearing feeling for the wearer is particularly likely to be felt in the crotch area, the non-fixed area 25 is more preferably formed in the central area C facing the crotch area, and more preferably over the entire central area C, so that the improvement in the wearing feeling can be more vividly felt.

[0048] Furthermore, the non-fixed area 25 may extend beyond the boundary between the central area C and the front area F forward. For example, as shown in FIG. 1, the non-fixed area 25 may extend in the front-rear direction D1 from near the center of the front-rear direction D1 of the front area F to near the center of the front-rear direction D1 of the rear area R. Thereby, since the back sheet and the skin-side structure portion 15 can slide relative to each other in a larger range, the skin-side structure portion 15 can follow the skin well while remaining in close contact with the wearer's skin (high followability to the skin), and an absorbent article with a better wearing feeling can be provided.

[0049] As described above, when the non-fixed area 25 extends from the rear part of the front area F to the front part of the rear area R, that is, when it extends from a position beyond the boundary between the central area C and the front area F forward to a position beyond the boundary between the central area C and the rear area R backward, the position of the front end of the non-fixed area 25 may be a position separated from the front end of the front area F by preferably 30% or more and 80% or less, more preferably 50% or more and 70% or less of the length of the front-rear direction D1 of the front area F. Also, the position of the rear end of the non-fixed area 25 may be a position separated from the rear end of the rear area R by preferably 30% or more and 80% or less, more preferably 40% or more and 70% or less of the length of the front-rear direction D1 of the rear area R.

[0050] Areas other than the non-fixed area 25 are fixed areas 21 in which the back sheet 2 and the skin-side structure 15 are bonded together by adhesive 8 or other adhesive means. In the examples shown in Figures 1 and 2, the fixed areas 21 are formed by bonding the back sheet 2 and the skin-side structure 15 to the front area F and the rear area R, respectively, with the main adhesive 8b. In the wings wg, wg as well, the fixed areas 21 are formed by bonding the back sheet 2 and the side sheet 7 together with the side adhesive 8a.

[0051] In this embodiment, the location where the fixed area 21 is formed in the absorbent article body bd may be at least one of the front area F and the rear area R, preferably both. The smaller the area of ​​the fixed area 21, the larger the area of ​​the non-fixed area 25, which is preferable in that the back sheet 2 and the skin-side structure 15 can slide more easily (with less force) over a wider area, thus improving the skin-following ability of the skin-side structure 15 to the skin. However, the presence of the fixed area 21 is preferable in that it prevents the laminated structure of the absorbent article 1 from breaking and the absorbent article 1 from disintegrating even when a large force is applied to the absorbent article 1, thereby improving the robustness of the absorbent article 1.

[0052] When a fixed region 21 is formed in the front region F, the length of the fixed region 21 in the front-rear direction D1 from the front end of the front region F may be preferably 30% to 80%, more preferably 50% to 70%, of the length of the front region F in the front-rear direction D1. Similarly, when a fixed region 21 is formed in the rear region R, the length of the fixed region 21 in the front-rear direction D1 from the rear end of the rear region R may be preferably 30% to 85%, more preferably 40% to 70%, of the length of the rear region R in the front-rear direction D1.

[0053] The area of ​​the non-fixed region 25 in the overlapping region between the backsheet 2 and the absorbent portion 4, that is, the area of ​​the non-fixed region 25 relative to the area of ​​the absorbent portion 4, is preferably 50% or more, more preferably 70% or more. Having the non-fixed region 25 be 50% or more of the absorbent portion 4 further improves the skin conformity of the absorbent article 1. The area of ​​the non-fixed region 25 in the main body bd, that is, the area of ​​the non-fixed region 25 relative to the area of ​​the main body bd, is also preferably 20% or more, more preferably 30% or more.

[0054] Furthermore, as shown in Figure 1, it is preferable that the fixed area 21 overlaps with at least one of the front end and rear end of the absorbent portion 4. As described above, the absorbent portion 4 contains particulate matter including superabsorbent polymer granules (SAP) and superabsorbent polymer fibers (SAF), so it is undesirable for such particulate matter to spill out of the absorbent portion 4. In particular, the front end and rear end of the absorbent portion 4 are usually not sealed or are only sealed by the pressure of the cutter during cutting, so there is a high possibility that particulate matter will spill out if force is applied. If particulate matter spills out of the absorbent portion 4 and adheres to the backsheet 2, irregularities may occur on the non-skin side surface of the backsheet 2. Therefore, if the fixing area 21 overlaps with at least one of the front and rear ends of the absorbent portion 4, the absorbent portion 4 is well fixed at at least one of the front and rear ends, and more preferably, if it overlaps with both the front and rear ends, the absorbent portion 4 is well fixed at both the front and rear ends, thus reducing the risk of the absorbent portion 4 moving, unraveling, and spilling its contents. Furthermore, it is also possible to reduce the impact of spilled granular material on the condition of the non-skin side surface of the backsheet 2. The area in which the fixing area 21 overlaps with the front or rear end of the absorbent portion 4 preferably includes the portion cut by a cutter or the like in the front-rear direction D1 (for example, the area shown in Figure 6). Also, the area in which the fixing area 21 overlaps with the absorbent portion 4 may be a range from the front edge or rear edge of the absorbent portion 4 (front or rear end of the cut position) in the front-rear direction D1, preferably 5 mm to 30 mm, more preferably 15 mm to 25 mm, depending on the shape of the cutting line of the absorbent portion 4. This range reduces the possibility of the contents spilling out by fixing the front-to-back end D1 of the absorbent portion 4 to the back sheet 2, and also prevents the fixed area 21 from increasing and the non-fixed area 25 from decreasing.

[0055] In this specification, "relatively slidable" means that the two members are able to slide relative to each other due to the force applied to the absorbent article when the user of the absorbent article handles it in the normal manner, and that this sliding is perceptible to the user of the absorbent article in the normal manner (i.e., by human senses such as sight and touch). Furthermore, the direction of sliding may be any direction perpendicular to the thickness of the absorbent article 1, and may include one or more directions inclined with respect to the front-to-back direction D1, the side-to-side direction D2, and the front-to-back direction D1 and / or the side-to-side direction D2 of the absorbent article 1. Therefore, even if there is a part within the fixed area 21 where the back sheet 2 and the skin-side structure 15 are not adhered, if they cannot slide relative to each other, that part is not included in the "unfixed area". For example, if the fixed area 21 is formed by applying adhesive in a spiral pattern using a spiral gun or spiral coater, a closed area where adhesive is not attached is formed. However, since the areas within such closed areas where adhesive is not attached are not relatively slidable between the back sheet 2 and the skin-side structure 15, these areas are not included in the non-fixed area 25. The same applies to a fixed area 21 formed by overlapping and applying multiple annular adhesives while shifting them in one direction.

[0056] As described above, the non-fixed area 25 is an area in which the backsheet 2 and the skin-side structure 15 can slide relative to each other, so it is preferable that it is an area having a certain degree of continuous area. For example, the non-fixed area 25 is preferably a continuous area in which the maximum length D1 in the front-to-back direction is 50 mm or more and the maximum length D2 in the lateral direction is 50 mm or more, and it is more preferable that it is a continuous area in which the maximum length D1 in the front-to-back direction is 60 mm or more and the maximum length D2 in the lateral direction is 60 mm or more. Furthermore, the non-fixed area 25 may be a continuous area in which the maximum length D1 in the front-to-back direction is greater than or equal to the length D1 in the front-to-back direction of the central area C and the maximum length D2 in the lateral direction is greater than or equal to the length D2 in the lateral direction of the absorbent part 4.

[0057] Furthermore, in this embodiment, the back sheet 2 and the skin-side structure 15 have a non-fixed region 25 that allows them to slide relative to each other. Therefore, when the back sheet 2 and the skin-side structure 15 are pulled in opposite directions in the lateral direction D2, the relative distance d1 of movement between the back sheet 2 and the skin-side structure 15 in the lateral direction D2 can be 10 mm or more. This distance d1 depends on the overall size of the absorbent article 1, but is preferably 15 mm or more, more preferably 20 mm or more, and even more preferably 30 mm or more. The above distance d1 may be a distance measured by the force applied when the absorbent article is handled in a normal manner. The distance d1 can be measured, for example, by attaching the anti-slip portion 9b to a substrate, gripping the substrate and the skin-side structure 15 respectively, and pulling them in opposite directions along the lateral direction D2 until a predetermined maximum load is applied. In this case, it is preferable to cover the substrate with a cloth similar to that used for underwear. Such a test can also be performed using a tensile testing machine. The "specified maximum load" may be, for example, the load that can be applied to the absorbent article 1 when it is handled in a normal manner, specifically 0.5 to 0.6 N / cm². ２ This refers to a certain degree of load, and does not include loads that would cause the structure of the absorbent article to break. More specifically, the displacement distance d1 can be measured under conditions such as those described in the embodiments below.

[0058] <Coefficient of friction of the backsheet> In the fixed area 21, the backsheet 2 and the skin-side structure 15, and especially the backsheet 2 and the absorbent part 4, are generally fixed using a fixing means such as an adhesive 8. Such fixing means can affect the properties of the backsheet 2. For example, when a hot melt adhesive is used as the fixing means, the heated hot melt adhesive is applied to the skin-side surface of the backsheet 2 and then cooled to room temperature, causing expansion and contraction of the backsheet 2 during the manufacturing process, and irregular bumps and dips that can be observed as wrinkles are likely to be formed on the backsheet 2.

[0059] In contrast, in one embodiment of the present disclosure, an unfixed region 25 is formed in which the back sheet 2 and the skin-side structure 15 are not fixed. More specifically, the state of the unfixed region 25 is described as follows: if M1 is the average deviation (MMD) of the coefficient of dynamic friction of the non-skin-side surface of the back sheet 2 in the unfixed region 25, and M0 is the average deviation (MMD) of the coefficient of dynamic friction of the non-skin-side surface of the back sheet 2 in the fixed region 21, then M1 < M0. In other words, the non-skin-side surface of the back sheet 2 is smoother in the unfixed region 25, and irregularities such as wrinkles are reduced.

[0060] The average deviation of the dynamic friction coefficient in the above characteristics can be measured, for example, by a friction measuring instrument such as a multi-functional static-dynamic friction measuring instrument. Furthermore, while the above characteristics can be measured by comparing the measured values ​​in the non-fixed region 25 and the measured values ​​in the fixed region 21 of the same or similar absorbent article 1, it is also possible to substitute this with the measured value measured on the non-skin side of the backsheet of an absorbent article having the same configuration except for the absence of a non-fixed region.

[0061] Thus, because the non-skin side of the backsheet 2 is smooth in the non-fixed area 25, even when the non-skin side of the absorbent article 1 is seen by the user, a smooth surface of the backsheet 2 without wrinkles or other irregularities can be observed, which may give the user a good impression.

[0062] Furthermore, the smooth surface of the non-skin side of the backsheet 2 also brings the following effects. In absorbent articles, a slip-prevention portion 9b (for example, Figure 1) is usually formed on the non-skin side of the backsheet 2, and the slip-prevention portion 9b is often a layer of adhesive. Therefore, when the slip-prevention portion 9b is provided on the non-skin side of the backsheet 2, if the slip-prevention portion 9b is provided in the non-fixed area 25, the layer of the slip-prevention portion 9b will be formed on a smooth surface, so the slip-prevention portion 9b can adhere well to the non-skin side of the backsheet 2. In addition, the surface of the slip-prevention portion 9b facing the underwear will also be smooth with few irregularities, so when the slip-prevention portion 9b is adhered to the underwear, the adhesion between the slip-prevention portion 9b and the underwear will also be high. As a result, the absorbent article 1 is more securely fixed to the underwear via the slip-prevention portion 9b. In other words, the function of the slip-prevention portion 9b in preventing the absorbent article 1 from shifting away from the underwear can be improved.

[0063] Furthermore, the ratio of the difference between the average deviation of the coefficient of dynamic friction of the non-skin side surface of the backsheet 2 in the fixed region 21 (M0) and the average deviation of the coefficient of dynamic friction of the non-skin side surface of the backsheet 2 in the non-fixed region 25 (M1) to the above M0, i.e., (M0 - M1) / M0 * 100 (%), is preferably 5% or more, more preferably 8% or more. This makes the non-skin side surface of the backsheet 2 smoother in the non-fixed region 25, further enhancing the visual impression of the non-skin side of the absorbent article 1, and consequently improving the adhesion of the anti-slip portion to the backsheet 2 and underwear.

[0064] M1 may be 0.58 or less, more preferably 0.57 or less, even more preferably 0.56 or less, or 0.55 or less, depending on the material of the back sheet 2.

[0065] Furthermore, if U1 is defined as the average value (MIU) of the kinetic friction coefficient of the non-skin side surface of the backsheet 2 in the non-fixed region 25, and U0 is defined as the average value (MIU) of the kinetic friction coefficient of the non-skin side surface of the backsheet 2 in the fixed region 21, then U1 < U0 may occur.

[0066] <Specific arrangement of anti-slip portion> As described above, if the anti-slip portion 9b is provided in the non-fixed area 25, the anti-slip portion 9b will adhere more easily to the backsheet 2 and to the underwear, thereby enhancing the original function of the anti-slip portion 9b, which is preferable. Therefore, from the viewpoint of enhancing the original function of the anti-slip portion 9b, it is preferable that a large proportion of the anti-slip portion 9b is located in the non-fixed area 25. For example, it is preferable that 50% or more, more preferably 60% or more, even more preferably 70% or more, 80% or more, 90% or more, or 95% or more of the total area of ​​the anti-slip portion 9b overlaps with the non-fixed area 25. Furthermore, as shown in Figure 1, it is preferable that almost all or the entire anti-slip portion 9b overlaps with the non-fixed area 25. In other words, it is preferable that 50% or less, more preferably 40% or less, even more preferably 30% or less, 20% or less, 10% or less, or 5% or less of the total area of ​​the anti-slip portion 9b overlaps with the fixed area 21. Furthermore, as shown in Figure 1, it is preferable that the anti-slip portion 9b hardly overlaps with the fixed area 21, or does not overlap it at all.

[0067] <Modifications> The following describes modifications of the absorbent article of this disclosure.

[0068] Figures 6 and 7 show modified examples of the absorbent article 1. The example shown in Figure 6 has the same configuration as the absorbent article 1 shown in Figure 1, except that the ranges of the non-fixed area 25 and the fixed area 21 are different. Both examples shown in Figures 6 and 7 have a non-fixed area 25 in which the backsheet 2 and the skin-side structure 15 are not fixed, so the absorbent article conforms well to the skin and provides an absorbent article 1 with excellent wearing comfort. In addition, in both examples, the average deviation of the coefficient of dynamic friction of the non-skin side surface of the backsheet 2 is smaller in the non-fixed area 25 than in the fixed area 21, and the non-skin side surface of the backsheet 2 in the non-fixed area 25 is smooth. Therefore, the appearance is good. Furthermore, the adhesion of the anti-slip portion 9b to the surface of the backsheet 2 and the adhesion of the anti-slip portion 9b to the underwear are improved, and the function of the anti-slip portion 9b is improved.

[0069] In the example shown in Figure 6, the configuration (size and position) of the anti-slip portion 9b is the same as in the example shown in Figure 1, but the range of the fixing area 21 formed in the front area F and the rear area R is wider than in the example shown in Figure 1. As a result, the front and rear ends of the anti-slip portion 9b overlap the fixing area 21. The range of the fixing area 21 can be made wider, for example, from the viewpoint of ensuring the robustness of the absorbent article 1 as described above, and preventing the contents of the absorbent portion 4 from spilling. If such viewpoints are considered important, the anti-slip portion 9b may be configured to overlap the fixing area 21, as long as it does not hinder the improvement of the overall function of the anti-slip portion 9b, while ensuring a good impression of the non-skin side of the absorbent article 1 due to the smoothness of the non-skin side surface of the backsheet 2.

[0070] Furthermore, in the example shown in Figure 7, the configuration (size and position) of the anti-slip portion 9b is the same as in the example shown in Figure 1, but the range of the fixing area 21 in the front area F is wider than in the example shown in Figure 1, and the front end of the anti-slip portion 9b overlaps with the fixing area 21. In the example shown in Figure 7, there is no fixing area 21 in the rear area R of the absorbent article body bd, and the rear end of the anti-slip portion 9b does not overlap with the fixing area 21. In the example shown in Figure 7, the anti-slip portion 9b does not overlap with the fixing area 21 across the entire central area C and rear area R, but overlaps with the non-fixed area 25. As a result, the adhesion of the anti-slip portion 9b to the backsheet 2 and to the underwear is improved across the entire central area C and rear area R, so that the absorbent article 1 can be fixed to the underwear more securely. The posterior region R is the area that faces the wearer's buttocks and is an area where the absorbent article 1 is easily deformed. By preventing the posterior region R from shifting away from the underwear, the wearer will be more likely to feel a reduction in shifting.

[0071] In addition to the configuration shown in Figure 7, in which there is no fixed area 21 in the rear region R, a configuration in which there is a fixed area 21 in the rear region R but no fixed area 21 in the front region F is also conceivable. In that case, the non-skin side surface of the back sheet 2 in the front region F can be made smoother, the function of the anti-slip portion 9b formed in the front region F can be enhanced, and slippage of the front region F from the underwear can be prevented. Opposite the front region F is the relatively flat front of the body, so the front region F is not easily deformed and is therefore a region that is relatively less likely to slip from the underwear. However, once it does slip, it is a region that is likely to cause significant discomfort, so preventing slippage of the front region F from the underwear is also important.

[0072] As described above, even in a configuration where no fixing area 21 is provided in the front area F or rear area R in addition to the central area C, the top sheet 3 or side sheet 7 and the back sheet 2 may be fixed to the front and rear of the absorbent article 1 by adhesive or other fixing means such as heat sealing. This prevents the absorbent article 1 from falling apart and enhances the robustness of the absorbent article 1.

[0073] <About the Manufacturing Process> Figure 8 illustrates a part of the process in the manufacturing method of the absorbent article 1 according to one embodiment. In Figure 8, an adhesive is applied to a long backsheet strip 2Z while it is being transported with its length direction being the transport direction Dt. For example, a hot melt adhesive is used as the adhesive. On the backsheet strip 2Z, the planned cutting contour (dotted line) of the absorbent article 1 is set. Then, a strip-shaped central adhesive 8bZ corresponding to the main adhesive 8b of the final absorbent article 1 is applied intermittently to the center of the backsheet strip 2Z in a direction perpendicular to the transport direction Dt (the center of the lateral direction D2 of the absorbent article 1), so as to form an unfixed region 25 later. However, in this case, the application is carried out continuously over a range that spans the rear region R of one absorbent article and the front region F of another absorbent article adjacent to that absorbent article 1. Furthermore, on the outer side of the backsheet strip 2Z in a direction perpendicular to the transport direction Dt (outside the lateral direction D2 of the absorbent article 1), a strip-shaped side adhesive 8aZ corresponding to the side adhesive 8a of the final absorbent article 1 is continuously applied.

[0074] In Figure 8, the central strip adhesive 8bZ and the side strip adhesive 8aZ both indicate areas where adhesive is applied. The adhesive may be applied as a solid coating within these areas, or it may be applied in dots or lines. For example, it may be linear, curved, spiral, etc., extending along the transport direction Dt. A hot melt coater, more specifically a gravure coater, spray coater, spiral gun, bead gun, etc., can be used to apply the adhesive 8.

[0075] After applying the adhesive, the absorbent portion 4, the long top sheet strip which will become the top sheet 3, and the long side sheet strip which will become the side sheet 7 can be overlapped with the adhesive as needed, and after heat sealing or the like may be applied, they can be cut to obtain the absorbent article 1 (Figure 1, etc.). In Figure 8, the arrangement of the anti-slip portion 9b is shown by a dashed line. For example, it can be provided by pre-applying it to a release sheet and then placing the release sheet with the anti-slip portion applied to it at a predetermined position on the non-skin side of the back sheet strip 2Z. After that, the skin-side components (in this example, the absorbent portion 4, the top sheet strip, and the side sheet strips) can be laminated with the adhesive.

[0076] The absorbent article 1 described above was a product with wings, but the same effect can be obtained with a product without wings using the above configuration. However, the product with wings allows the back sheet 2 to be firmly fixed to the underwear, making it easier for the back sheet 2 and the skin-side structure 15 to slide relative to each other, thus improving the wearing comfort.

[0077] Furthermore, the technology disclosed herein is applicable to sanitary napkins, panty liners, incontinence pads, and diapers, but is particularly suitable for use with sanitary napkins. Since sanitary napkins are often used with the skin side in close contact with the genital area, friction between the absorbent material and the skin is more likely to occur due to the wearer's movements compared to other absorbent items. Therefore, by using the embodiment of the disclosed invention in sanitary napkins, a better wearing experience is more easily felt compared to conventional products.

[0078] The embodiments of this disclosure will be described in more detail below with reference to examples.

[0079] <Preparation of absorbent material> (Example 1) As Example 1, a commercially available conventional product P (manufactured by Daio Paper Corporation, with wings, 23 cm) that does not have a non-fixed area was used. Conventional product P has the same arrangement of fixed areas and anti-slip parts as described with reference to Figures 4 and 5, and adhesive 8 is placed over the entire surface of the back sheet, fixing the back sheet and the structure on top of it (skin-side structure part), so that the back sheet and the skin-side structure part cannot slide relative to each other with the normal force of the user.

[0080] (Example 2) A sanitary napkin was prepared that had the same basic structure as the conventional product P in Example 1, and the arrangement of the anti-slip parts was also the same, but it had a non-fixed area. The sanitary napkin in Example 2 had the same arrangement of fixed areas as described with reference to Figures 1 to 3.

[0081] <Method for measuring the coefficient of friction> For each example, the measurement area was defined as a region of 10 mm in the horizontal direction and 50 mm in the front-to-back direction, in the area on the side of the central region of the non-skin side of the backsheet of the sanitary napkin where the absorbent part overlaps and no anti-slip part is provided (the region outside the outermost lateral edge of the anti-slip part located in the lateral direction). The above measurement area is included in the fixed area in Example 1 and in the non-fixed area in Example 2. The measurement area for each example was cut out and further disassembled to obtain a test piece consisting of the backsheet 2, adhesive, and covering sheet 4b for Example 1, and a test piece consisting of the backsheet 2 and covering sheet 4b overlapping for Example 2.

[0082] A multi-functional static-dynamic friction measuring instrument (TL201Tt, manufactured by Trinity Lab Co., Ltd.) was used for the measurements. More specifically, the test specimens taken from each example were fixed on the test stand with the non-skin side of the backsheet facing upwards, and a 10 mm wide line contact was brought into contact with the test specimen, applying a load of 10 g. The line contact was then moved back and forth in the forward and backward direction for a one-way distance of 50 mm. The speed at which the line contact was moved was 300 mm / min. Measurements were performed three times for each example, and the average value of the mean deviation (MMD) of the dynamic friction coefficient was calculated.

[0083] <Results and Discussion> The average value of the average deviation of the coefficient of dynamic friction was 0.572 for Example 1 (conventional product) and 0.524 for Example 2 (embodiment of the present disclosure). Thus, the average deviation of the coefficient of dynamic friction in Example 2 was smaller than the average deviation of the coefficient of dynamic friction in Example 1. Furthermore, when the measured parts of each example were visually observed and compared, many wrinkles were observed in the back sheet of Example 1, but almost no wrinkles were observed in the back sheet of Example 2.

[0084] In this embodiment, the coefficient of dynamic friction in the fixed area of ​​the sanitary napkin in Example 2 was not measured. However, it is considered that the measured value of the coefficient of dynamic friction in the fixed area of ​​Example 2 will be equivalent to the measured value of the coefficient of dynamic friction in the fixed area of ​​the sanitary napkin in Example 1. Therefore, by comparing the mean deviation (MMD) of the coefficient of dynamic friction between Example 1 and Example 2, it is considered that a comparison was made between the mean deviation (MMD) of the coefficient of dynamic friction in the non-fixed area and the mean deviation (MMD) of the coefficient of dynamic friction in the fixed area of ​​Example 1. Thus, from the above results, it is understood that in the sanitary napkin of Example 2 according to this disclosure, if the mean deviation of the coefficient of dynamic friction in the fixed area is M0 and the mean deviation of the coefficient of dynamic friction in the non-fixed area is M1, then M0 > M1, and (M0 - M1) / M0 × 100 (%) is approximately 8.4%.

[0085] Although the present disclosure has been described above based on embodiments, the present disclosure is not limited to these embodiments. The above embodiments can be modified, altered, replaced, added, deleted, and combined in various ways within the scope of the claims, and these also fall within the technical scope of the present disclosure. Furthermore, the above-mentioned components can be combined in any way.

[0086] The specific aspects of this disclosure are further described below.

[0087] (Note 1) The embodiment of Note 1-1 is an absorbent article having an impermeable backsheet and a skin-side structure disposed on the skin side of the backsheet, wherein the skin-side structure includes an absorbent portion directly disposed on the skin side of the backsheet and a permeable topsheet disposed on the skin side of the absorbent portion, wherein the backsheet and the skin-side structure are not fixed, and the backsheet and the skin-side structure have a non-fixed region in which they can slide relative to each other and a fixed region other than the non-fixed region, wherein the average deviation of the coefficient of dynamic friction of the non-skin side surface of the backsheet in the non-fixed region is smaller than the average deviation of the coefficient of dynamic friction of the non-skin side surface of the backsheet in the fixed region.

[0088] Absorbent items are used by attaching them to underwear with the backsheet side facing outwards. When the wearer's body moves, the underwear moves in accordance with that movement, and the absorbent item also moves in accordance with the movement of the underwear (including deformation and / or shifting). In this case, even though the absorbent item moves in accordance with the movement of the underwear, the skin in the crotch area to which the skin-facing side of the absorbent item is in contact does not move much, so friction is likely to occur between the skin-facing side (topsheet side) of the absorbent item and the skin in contact with that side. For this reason, especially when the absorbent item is worn for a long time or when there is vigorous movement, the feeling of wearing it may be impaired due to friction.

[0089] In contrast, the absorbent article according to the above-described embodiment 1 has an unfixed region where the back sheet and the skin-side structure are not fixed, and is configured so that the back sheet and the skin-side structure can slide relative to each other. As a result, one of the opposing back sheets and skin-side structures can move independently along the surface relative to the other. Therefore, even if the back sheet moves in accordance with the movement of the underwear while the absorbent article is in close contact with the wearer's skin, the movement of the back sheet is not directly transmitted to the skin-side structure, preventing the absorbent article from rubbing against the skin. In other words, because the components inside the absorbent article are relatively slidable, even if the back sheet moves in accordance with the underwear, the skin-side surface of the absorbent article can follow the wearer's skin and maintain close contact with the skin, making it difficult for friction to occur between the absorbent article and the skin, thus improving the wearing comfort.

[0090] Furthermore, in this embodiment, the average deviation of the coefficient of dynamic friction on the non-skin side of the backsheet is smaller in the non-fixed region than in the fixed region. That is, the non-skin side of the backsheet in the non-fixed region is smoother and wrinkles are reduced. As a result, when the user looks at the non-skin side of the absorbent article, a smooth surface is observed on the non-skin side of the backsheet, resulting in a better visual impression. Moreover, if an anti-slip portion is further provided on the non-skin side of the backsheet, the adhesion of the anti-slip portion to the backsheet surface is increased, and the surface of the anti-slip portion itself that faces the underwear also becomes smoother, thus increasing the adhesion of the anti-slip portion to the underwear.

[0091] Furthermore, in this embodiment, since a fixing area is provided, the back sheet and the skin-side structure are partially fixed in the thickness direction, which reduces the possibility of the laminated structure of the absorbent article breaking when a large force is applied to the absorbent article.

[0092] (Note 2) In the embodiment of Note 2, the absorbent article has a front-to-back direction corresponding to the front-to-back direction of the body when worn, and a lateral direction perpendicular to the front-to-back direction, and further has a central region including a portion facing the body fluid outlet that faces the body fluid outlet of the wearer when worn, a front region in front of the central region, and a rear region behind the central region, and the non-fixed region is formed over the entire front-to-back direction of the central region and over the entire lateral direction of the absorbent portion.

[0093] According to the embodiment described in Appendix 2 above, since the non-fixed area is formed over the entire front-to-back direction of the central area and over the entire lateral direction of the absorbent part, the back sheet and the skin-side structure can easily slide relative to each other over a large range in the lateral direction, and the skin-side surface of the absorbent article conforms more easily to the wearer's skin (hereinafter also referred to as conformability). Furthermore, since the central area is an area where the wearer is likely to feel friction between the absorbent article and their skin, this embodiment makes it even easier to feel an improvement in wearing comfort. In addition, if an anti-slip portion is provided, the anti-slip portion, which has high adhesion to both the non-skin side of the back sheet and the underwear, can be expanded in the front-to-back direction to match the range of the non-fixed area.

[0094] (Note 3) In the embodiment of Note 3, the area of ​​the non-fixed region in the overlapping region of the backsheet and the absorbent portion is 50% or more of the area of ​​the overlapping region.

[0095] According to the embodiment described in Appendix 3 above, by having a ratio of the area of ​​the non-fixed region to the area of ​​the overlapping region between the backsheet and the absorbent portion to a predetermined value or greater, the backsheet and the skin-side structure can slide relatively large, improving the conformability of the skin-side surface of the absorbent article to the skin. Furthermore, if a slip-prevention portion is provided, the slip-prevention portion, which has high adhesion to both the non-skin-side surface of the backsheet and the underwear, can be enlarged to match the range of the non-fixed region.

[0096] (Note 4) In the embodiment of Note 4, the non-fixed region further extends beyond the boundary between the central region and the front region in the forward direction, or beyond the boundary between the central region and the rear region in the rear direction.

[0097] In the embodiment described in Appendix 4 above, the range of the non-fixed area is wider, and the range in which relative sliding between the backsheet and the skin-side structure is possible is widened, so the conformability of the skin-side surface of the absorbent article to the skin is further improved. In addition, in the case of an absorbent article equipped with a slip-prevention portion, the slip-prevention portion, which has high adhesion to both the non-skin-side surface of the backsheet and the underwear, can be expanded in the front-to-back direction to match the range of the non-fixed area.

[0098] (Note 5) In the embodiment of Note 5, the fixed area is formed to overlap the front end and rear end of the absorbent portion.

[0099] As described above, the non-fixed area is the area where the backsheet and the skin-side structure move relative to each other, and when such relative movement occurs, force is also applied to the absorbent part itself contained in the skin-side structure. Since the absorbent part contains particulate matter including superabsorbent polymer granules and superabsorbent polymer fibers, when force is applied, such particulate matter may spill out of the absorbent part. If particulate matter spills out of the absorbent part and adheres to the backsheet, irregularities may occur on the non-skin side of the backsheet. In contrast, according to the embodiment described in Appendix 5 above, the fixed area where the backsheet and the skin-side structure are fixed overlaps the front and rear ends of the absorbent part. As a result, the front and rear ends of the absorbent part are fixed to the backsheet, and relative movement with respect to the backsheet is reduced. Therefore, it is possible to prevent the components of the absorbent part from spilling out of the absorbent part at the front and rear, and to prevent irregularities from occurring on the non-skin side of the backsheet.

[0100] (Note 6) In the embodiment of Note 6, anti-slip portions for securing the absorbent article to the underwear when worn are provided on the non-skin side of the back sheet in the front region, the central region, and the rear region, and in the front region or the rear region, the anti-slip portions do not overlap with the fixing region.

[0101] According to the embodiment described in Appendix 6 above, the anti-slip portion is provided on the non-skin side of the backsheet, which securely fixes the absorbent material to the underwear, preventing the absorbent material from shifting away from the underwear and preventing leakage of bodily fluids.

[0102] Furthermore, as described above for the embodiment of Appendix 1, the absorbent article has an unfixed region where the backsheet and the skin-side structure are not fixed, and in the unfixed region the average deviation of the coefficient of dynamic friction of the non-skin-side surface of the backsheet is smaller, and as described above for the embodiment of Appendix 2, the unfixed region is formed over the entire front-to-back direction of the central region. Here, in the embodiment of Appendix 6, the anti-slip portion is formed in the central region, so the anti-slip portion is securely provided in the unfixed region, that is, in the region where the non-skin-side surface of the backsheet is smooth. For this reason, the anti-slip portion can adhere closely along the non-skin-side surface of the backsheet. In addition, the smoothness of the non-skin-side surface of the backsheet is reflected in the anti-slip portion itself, and the surface of the anti-slip portion facing the underwear is also smooth, so the anti-slip portion can adhere closely to the underwear. Thus, the function of the anti-slip portion in securely fixing the absorbent article to the underwear can be improved.

[0103] (Note 7) In the embodiment of Note 7, the entire anti-slip portion does not overlap with the fixed area.

[0104] According to the embodiment described in Appendix 7 above, since the anti-slip portion does not overlap the fixed area overall, the area in which the anti-slip portion overlaps the non-fixed area, that is, the area in which the anti-slip portion is provided on the smoother non-skin side of the backsheet in the non-fixed area, can be increased. As a result, the adhesion of the anti-slip portion to the backsheet and to the underwear can be improved, and the function of the anti-slip portion can be enhanced.

[0105] This application claims priority based on Japanese Patent Application No. 2024-169802, filed on 30 September 2024, the entire contents of which are incorporated herein by reference.

[0106] 1 Absorbent article 2 Back sheet 3 Top sheet 4 Absorbent body 4a Absorbent body 4b Wrapping sheet 7 Side sheet 8 Adhesive 8a Side adhesive 8b Body adhesive 9b Anti-slip part for body (anti-slip part) 9w Anti-slip part for wing 15 Skin-side structure 21 Fixed area 25 Non-fixed area bd Absorbent article body C Central area CL Front-to-back center line D1 Front-to-back direction (longitudinal direction) D2 Lateral direction (short direction) Dt Conveying direction F Front area Q Opposite part of body fluid outlet R Rear area wg Wing

Claims

1. An absorbent article having an impermeable backsheet and a skin-side structure disposed on the skin side of the backsheet, wherein the skin-side structure includes an absorbent portion directly disposed on the skin side of the backsheet and a permeable topsheet disposed on the skin side of the absorbent portion, the backsheet and the skin-side structure are not fixed together and the article has a non-fixed region in which the backsheet and the skin-side structure are relatively slidable, and a fixed region other than the non-fixed region, wherein the average deviation of the coefficient of dynamic friction of the non-skin side surface of the backsheet in the non-fixed region is smaller than the average deviation of the coefficient of dynamic friction of the non-skin side surface of the backsheet in the fixed region.

2. The absorbent article according to claim 1, wherein the absorbent article has a front-to-back direction corresponding to the front-to-back direction of the body when worn, and a lateral direction perpendicular to the front-to-back direction, and further has a central region including a portion facing a body fluid outlet that faces the body fluid outlet of the wearer when worn, a front region in front of the central region, and a rear region behind the central region, and the non-fixed region is formed over the entire front-to-back direction of the central region and over the entire lateral direction of the absorbent portion.

3. The absorbent article according to claim 2, wherein the area of ​​the non-fixed region in the overlapping region of the backsheet and the absorbent portion is 50% or more of the area of ​​the overlapping region.

4. The absorbent article according to claim 2 or 3, wherein the non-fixed region further extends forward beyond the boundary between the central region and the front region, or backward beyond the boundary between the central region and the rear region.

5. The absorbent article according to claim 2 or 3, wherein the fixing region is formed to overlap the front end and rear end of the absorbent portion.

6. The absorbent article according to claim 2 or 3, wherein the non-skin side of the backsheet is provided with anti-slip portions in the front region, the central region, and the rear region for securing the absorbent article to underwear when worn, and in the front region or the rear region, the anti-slip portions do not overlap with the fixing region.

7. The absorbent article according to claim 6, wherein the entire anti-slip portion does not overlap with the fixing area.

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