Absorbent articles

Abstract

This technology improves the wearing comfort by allowing the skin-facing side of the absorbent article to conform well to the wearer's skin, and also prevents wrinkles on the non-skin side of the absorbent article. [Solution] 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 is smaller in the non-fixed region than in the fixed region.

Description

Technical Field

[0001] The present disclosure relates to absorbent articles.

Background Art

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

[0003] As a means for preventing friction 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).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[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] Furthermore, in conventional absorbent products, the backsheet and the absorbent portion are usually fixed together (see, for example, Figures 4 and 5). Therefore, the effect of the fixing method (e.g., adhesive) is reflected in the condition of the backsheet, and wrinkles may be observed on the non-skin side of the backsheet. Although the non-skin side of an absorbent product is seen less frequently than the skin side, it may detract from the user's impression of the absorbent product at a glance.

[0007] In view of the above, one aspect of this disclosure aims to provide a technology that improves the wearing comfort by enabling the skin-side surface of the absorbent article to conform well to the wearer's skin, and that prevents wrinkles on the non-skin side of the absorbent article. [Means for solving the problem]

[0008] A first 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, wherein the backsheet and the skin-side structure are not fixed and the backsheet and the skin-side structure are relatively slidable in a non-fixed region 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] The absorbent material is used by attaching it 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 material also moves in accordance with the movement of the underwear (including deformation and / or shifting). In this case, even though the absorbent material moves in accordance with the movement of the underwear, the skin in the crotch area to which the skin-facing side of the absorbent material is in contact does not move much, so friction is likely to occur between the skin-facing side (topsheet side) of the absorbent material and the skin in contact with that side. For this reason, especially when the absorbent material is worn for a long time or when there is vigorous movement, the feeling of wearing it may be impaired due to friction.

[0010] In contrast, the absorbent article according to the first embodiment described above 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.

[0011] 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.

[0012] 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.

[0013] In a second aspect of the present disclosure, 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 bodily fluid outlet that faces the wearer's bodily fluid outlet when worn, a front region in front of the central region, and a rear region behind the central region, wherein the non-fixed region is formed over the entire central region and over the entire lateral direction of the absorbent portion.

[0014] According to the second embodiment described 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 ease with which the skin-side surface of the absorbent article conforms to the wearer's skin (hereinafter also referred to as conformability) is increased. 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 surface 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.

[0015] In a third aspect of this disclosure, 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.

[0016] According to the third embodiment described 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 region 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.

[0017] In a fourth aspect of the present disclosure, 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.

[0018] In the fourth embodiment described 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 also 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.

[0019] In a fifth aspect of the present disclosure, the fixed region is formed to overlap the front and rear ends of the absorbent portion.

[0020] As described above, the non-fixed region is a region 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 portion itself contained in the skin-side structure. Since the absorbent portion contains particulate matter including superabsorbent polymer granules and superabsorbent polymer fibers, when force is applied, such particulate matter may spill out of the absorbent portion. If particulate matter spills out of the absorbent portion and adheres to the backsheet, irregularities may occur on the non-skin-side surface of the backsheet. In contrast, according to the fifth embodiment described above, the fixed region to which the backsheet and the skin-side structure are fixed overlaps the front and rear ends of the absorbent portion. As a result, the front and rear ends of the absorbent portion 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 portion from spilling out of the absorbent portion at the front and rear, and to prevent irregularities from occurring on the non-skin-side surface of the backsheet.

[0021] In a sixth aspect of the present disclosure, 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 the underwear when worn, wherein the anti-slip portions in the front region or the rear region do not overlap with the fixing region.

[0022] According to the sixth aspect described above, since the displacement prevention portion is provided on the non-skin side of the backsheet, the absorbent article can be securely fixed to the underwear, preventing the absorbent article from shifting from the underwear, and preventing leakage of body fluids and the like.

[0023] Further, as described above for the first aspect, the absorbent article has a non-fixed region where the backsheet and the skin-side structure portion are not fixed. In the non-fixed region, the average deviation of the coefficient of kinetic friction of the surface on the non-skin side of the backsheet is smaller. As described above for the second aspect, the non-fixed region is formed over the entire front-back direction of the central region. Here, according to the sixth aspect described above, since the displacement prevention portion is formed in the central region, the displacement prevention portion is surely provided in the non-fixed region, that is, in the region where the surface on the non-skin side of the backsheet is smooth. Therefore, the displacement prevention portion can adhere along the surface on the non-skin side of the backsheet. Further, the smoothness of the surface on the non-skin side of the backsheet is also reflected in the displacement prevention portion itself, and the surface of the displacement prevention portion facing the underwear is also smooth, so that the displacement prevention portion can be made to adhere to the underwear. Thus, the function of the displacement prevention portion to securely fix the absorbent article to the underwear can be improved.

[0024] In the seventh aspect of the present disclosure, the entire displacement prevention portion does not overlap the fixed region.

[0025] According to the seventh aspect described above, since the displacement prevention portion does not entirely overlap the fixed region, the range in which the displacement prevention portion overlaps the non-fixed region, that is, the range in which the displacement prevention portion is provided on the smoother non-skin side surface of the non-fixed region can be increased. Therefore, the adhesion of the displacement prevention portion to the backsheet and the adhesion to the underwear can be enhanced, and the function of the displacement prevention portion can be improved.

Effects of the Invention

[0026] According to one aspect of the present disclosure, it is possible to provide a technique for improving the wearing feeling by enabling the surface on the skin side of the absorbent article to follow well with the skin of the wearer, and preventing wrinkles on the non-skin side of the absorbent article.

Brief Description of the Drawings

[0027] [Figure 1] This is a plan view of an absorbent article according to one embodiment of the present disclosure, as seen from the skin side. [Figure 2] This is a cross-sectional view taken along line II in Figure 1. [Figure 3] This is a cross-sectional view taken along line II-II in Figure 1. [Figure 4] This is a plan view of an absorbent article relating to the conventional technology, as seen from the skin side. [Figure 5] This is a cross-sectional view along the line I'-I' in Figure 4. [Figure 6] This is a plan view of an absorbent article relating to a modified example. [Figure 7] This is a plan view of an absorbent article relating to a modified example. [Figure 8] This is a diagram illustrating a part of the manufacturing process of an absorbent article according to one embodiment. [Modes for carrying out the invention]

[0028] 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.

[0029] 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.

[0030] <Basic composition of absorbent materials> 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 along line II of Figure 1, and Figure 3 shows a cross-sectional view along line II-II of 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 laminated members without an intervening gray area are in direct contact or can be in direct contact, but are not joined or fixed to each other.

[0031] 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. Furthermore, 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, the topsheet 3, or another layer other than the absorbent portion 4 and topsheet 3, such as the sidesheet 7, may also 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.

[0032] The absorbent article 1 may be equipped with wings wg, wg extending from both sides. The wings wg, wg are for securely fixing the absorbent article 1 to the underwear when worn. 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, the absorbent article 1 shown in Figures 1 to 3 has a shape and structure that is approximately symmetrical with respect to the center line (front-to-back center line) CL extending in the front-to-back direction, but the structure of the absorbent article does not necessarily have to be symmetrical.

[0033] The portion Q facing the bodily fluid outlet shown in Figure 1 is the part that faces the wearer's vaginal opening or other bodily fluid outlet when worn, and is located on the anterior-posterior center line CL. 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.

[0034] 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).

[0035] 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 preferably 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 compressed area in the thickness direction. However, the absorbent article body bd may have a configuration in which the absorbent part 4 is partially bulged by bulging a part of the absorbent part 4, for example, the area opposite the body fluid outlet Q and the area near it, and the center of the width direction D2 of the rear area.

[0036] One embodiment of the present 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.

[0037] 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.

[0038] 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 positioned 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 positioned 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.

[0039] As the backsheet 2, a sheet material having at least water-impermeable properties, such as an olefin resin sheet made 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, it is even more desirable to use a material that has moisture permeability from the viewpoint of preventing stuffiness. 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.

[0040] 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.

[0041] 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.

[0042] As shown in Figures 2 and 3, the absorbent body 4 can be configured to include an absorbent body 4a that substantially absorbs bodily fluids, and a covering sheet 4b that encloses the absorbent body 4a.

[0043] 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 due to their long fiber length. The absorbent body 4a can be manufactured by the fiber stacking or airlaid method. In addition, 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, so-called SAP sheets, can also be used. When using SAP sheets, the encasing sheet 4b can be omitted.

[0044] 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 (with 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 also be used. Furthermore, hydrophobic fibers can be surface-treated with a hydrophilizing agent to impart affinity to body fluids.

[0045] The structure in which the absorbent body 4a is encased in a 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.

[0046] 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 body 4, and consequently friction between the back sheet 2 and the skin-side structure 15 on the skin side of the back sheet 2, an air-through nonwoven fabric is preferred.

[0047] Furthermore, an intermediate sheet may be provided between the top sheet 3 and the absorbent section 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 may be the same as the material of the top sheet 3 described above.

[0048] <Basic structure of the anti-slip section> The non-skin side of the backsheet 2 of the absorbent article body bd is provided with an anti-slip portion 9b (hereinafter also referred to as the anti-slip portion for the main body). When the absorbent article 1 is worn, the anti-slip portion 9b can be attached to the underwear to prevent the absorbent article 1 from shifting away from the underwear.

[0049] 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 the absorbent article 1 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 styrene polymers, tackifiers, plasticizers, or combinations thereof.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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-to-back 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.

[0054] Furthermore, the anti-slip portion 9b may be arranged in a known format other than those described above.

[0055] 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 ensure that the wing wg is 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.

[0056] <Securing the back sheet to the skin-side structural part> An absorbent article 1 according to one embodiment of the present disclosure has an unfixed region 25 in the absorbent article body bd where 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. First, the fixing of the back sheet 2 and the skin-side structural part 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.

[0057] 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 body (over the entire front-to-back direction D1 and the entire 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 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, including 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.

[0058] 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.

[0059] 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. This allows the skin-side structure 15 to follow the skin and the backsheet 2 to follow the underwear. Therefore, regardless of the movement of the backsheet 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 fit that could not be achieved by simply modifying the configuration of the topsheet 3 is obtained.

[0060] In the non-fixed region 25, the back sheet 2 and the skin-side structure 15 are directly laminated, 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.

[0061] In the example shown in Figure 1, the non-fixed area 25 is formed over the entire lateral direction D2 of the absorbent portion 4. This allows the entire lateral direction D2 of the absorbent portion 4 to slide relative to the backsheet 2, further improving the skin conformity of the skin-facing surface of the absorbent article 1. Alternatively, the non-fixed area 25 may be formed over both ends of the lateral direction D2 of the absorbent article body bd. In that case, it is preferable that the edges of the lateral direction D2 of the absorbent article body bd are closed by applying adhesive to the edges or by applying a sealing process such as heat sealing, in the front region F and rear region R in the configuration with wings wg, and over the entire front-to-back direction D1 in the configuration without wings wg.

[0062] Furthermore, as shown in Figures 1 and 2, it is preferable that the outer end of the non-fixed region 25 in the lateral direction D2 and the outer end of the absorbent portion 4 in the lateral direction D2 are separated by a length k in the lateral direction D2. This separation provides play for the absorbent portion 4, making it easier for the absorbent portion 4 to move relative to the backsheet 2, thereby improving the skin-side structure portion 15's conformity to the skin. The length k in the lateral direction D2 between the outer end of the non-fixed region 25 in the lateral direction D2 and the outer end of the absorbent portion 4 in the lateral direction D2 is preferably 0.5 mm or more and 5 mm or less, and more preferably 1 mm or more and 3.5 mm or less.

[0063] Furthermore, if the backsheet 2 and the skin-side structure 15 are relatively slidable, the non-fixed area 25 does not necessarily have to be formed over the entire length of the lateral direction D2. For example, the lateral adhesive 8a may be extended so that the edge of the absorbent part 4 in the lateral direction D2 extends beyond the center, thereby bonding the end of the absorbent part 4 in the lateral direction D2 to the backsheet 2 along the front-rear direction D1. In that case, the length of the lateral direction D2 to which the backsheet 2 and the absorbent part 4 are bonded is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less.

[0064] The non-fixed area 25 may be formed in the central area C, preferably extending over the entire central area C as shown in Figure 1, and more specifically beyond the front and rear ends of the central area C, respectively. Since the difference in fit is particularly easily felt by the wearer in the crotch area, the improvement in fit can be more readily perceived by having the non-fixed area 25 formed in the central area C facing the crotch area, more preferably over the entire central area C.

[0065] Furthermore, the non-fixed region 25 may extend forward beyond the boundary between the central region C and the front region F. For example, as shown in Figure 1, the non-fixed region 25 may extend in the front-to-back direction D1 from near the center of the front-to-back direction D1 of the front region F to near the center of the front-to-back direction D1 of the rear region R. This allows the back sheet and the skin-side structure 15 to slide relative to each other over a larger range, improving the effect of the skin-side structure 15 to conform well to the wearer's skin while remaining in close contact with it (high conformability to the skin), and providing an absorbent article with a superior wearing comfort.

[0066] Furthermore, as described above, if the non-fixed region 25 extends from the rear of the front region F to the front of the rear region R, the position of the front end of the non-fixed region 25 may be at a distance from the front end of the front region F that is preferably 30% to 80%, more preferably 50% to 70%, of the length D1 in the front-rear direction of the front region F. Also, the position of the rear end of the non-fixed region 25 may be at a distance from the rear end of the rear region R that is preferably 30% to 80%, more preferably 40% to 70%, of the length D1 in the front-rear direction of the rear region R.

[0067] 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, the fixed areas 21 are also formed by bonding the back sheet 2 and the side sheet 7 with the side adhesive 8a.

[0068] 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.

[0069] If 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, if 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.

[0070] The area of ​​the non-fixed area 25 in the overlapping region between the backsheet 2 and the absorbent portion 4, that is, the area of ​​the non-fixed area 25 relative to the area of ​​the absorbent portion 4, is preferably 50% or more, more preferably 70% or more. Having the non-fixed area 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 area 25 in the main body bd, that is, the area of ​​the non-fixed area 25 relative to the area of ​​the main body bd, is also preferably 20% or more, more preferably 30% or more.

[0071] Furthermore, as shown in Figure 1, it is preferable that the fixed area 21 overlaps 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, thereby 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 range shown in Figure 6). Depending on the shape of the cutting line in which the absorbent portion 4 is cut, the area may be preferably 5 mm to 30 mm, more preferably 15 mm to 25 mm, in the front-rear direction D1 from the front edge or rear edge of the absorbent portion 4 (the front or rear end of the cut position). 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.

[0072] In this specification, "relatively slidable" means that the two components 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., through human senses such as sight and touch). 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 part where the adhesive is not attached is formed, but the part within such a closed part where the adhesive is not attached is not included in the unfixed area 21 because the back sheet 2 and the skin-side structure 15 cannot slide relative to each other. The same applies to a fixed area 21 formed by overlapping and applying multiple annular adhesives while shifting them in one direction.

[0073] 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.

[0074] 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 examples below.

[0075] <Coefficient of friction of the back seat> In the fixed area 21, the back sheet 2 and the skin-side structure 15, and especially the back sheet 2 and the absorbent part 4, are typically fixed using a fixing means such as an adhesive 8. Such fixing means can affect the properties of the back sheet 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 back sheet 2 and then cooled to room temperature. This causes expansion and contraction of the back sheet 2 during the manufacturing process, making it easy for irregular bumps and dips, which can be observed as wrinkles, to form on the back sheet 2.

[0076] In contrast, in one embodiment of the present disclosure, a non-fixed region 25 is formed where the backsheet 2 and the skin-side structure 15 are not fixed. To describe the state of the non-fixed region 25 more specifically, when the average deviation (MMD) of the coefficient of kinetic friction on the non-skin side surface of the backsheet 2 in the non-fixed region 25 is denoted as M1, and the average deviation (MMD) of the coefficient of kinetic friction on the non-skin side surface of the backsheet 2 in the fixed region 21 is denoted as M0, M1 < M0. That is, the non-skin side surface of the backsheet 2 is smoother in the non-fixed region 25, and the unevenness such as wrinkles is reduced.

[0077] The average deviation of the coefficient of kinetic friction in the above characteristics can be measured by a friction measuring instrument such as a multi-functional static and kinetic friction measuring instrument. Also, for the above characteristics, in the same or the same type of absorbent article 1, the measured value in the non-fixed region 25 may be compared with the measured value in the fixed region 21, but it can also be replaced with the measured value obtained by measuring the non-skin side surface of the backsheet of an absorbent article having the same configuration except for the absence of the non-fixed region.

[0078] Thus, since the non-skin side surface of the backsheet 2 is smooth in the non-fixed region 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 unevenness such as wrinkles can be observed, which can give a good impression to the user.

[0079] Furthermore, the smoothness of the non-skin side surface of the backsheet 2 also brings the following effects. That is, in absorbent articles, generally, a displacement prevention portion 9b (for example, in FIG. 1) is often formed on the non-skin side surface of the backsheet 2, and the displacement prevention portion 9b is often an adhesive layer. Therefore, when providing the displacement prevention portion 9b on the non-skin side surface of the backsheet 2, if the displacement prevention portion 9b is provided in the non-fixed region 25, the layer of the displacement prevention portion 9b will be formed on a smooth surface, so that the displacement prevention portion 9b can adhere well to the non-skin side surface of the backsheet 2. Also, since the surface of the displacement prevention portion 9b facing the underwear is also smooth with few irregularities, when the displacement prevention portion 9b is adhered to the underwear, the adhesion between the displacement prevention portion 9b and the underwear is also high. As a result, the absorbent article 1 is more securely fixed to the underwear via the displacement prevention portion 9b. In other words, the function of the displacement prevention portion 9b to prevent the displacement of the absorbent article 1 from the underwear can be improved.

[0080] Also, the ratio of the difference between the average deviation (M0) of the coefficient of kinetic friction of the non-skin side surface of the backsheet 2 in the fixed region 21 and the average deviation (M1) of the coefficient of kinetic friction of the non-skin side surface of the backsheet 2 in the non-fixed region 25 to M0, that is, (M0 - M1) / M0 * 100 (%) is preferably 5% or more, more preferably 8% or more. Thereby, the non-skin side surface of the backsheet 2 in the non-fixed region 25 becomes smoother, and the effect of improving the appearance impression of the non-skin side of the absorbent article 1, and thus further increasing the adhesion of the displacement prevention portion to the backsheet 2 and the underwear can be achieved.

[0081] M1 depends on the material of the backsheet 2, but is preferably 0.58 or less, more preferably 0.57 or less, still more preferably 0.56 or less, 0.55 or less.

[0082] In addition, when the average value (MIU) of the coefficient of kinetic friction of the non-skin side surface of the backsheet 2 in the non-fixed region 25 is U1 and the average value (MIU) of the coefficient of kinetic friction of the non-skin side surface of the backsheet 2 in the fixed region 21 is U0, U1 < U0 can be obtained.

[0083] <Specific placement of anti-slip parts> 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 both the backsheet 2 and 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 entirety of the 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.

[0084] <Variation> The following describes some variations of the absorbent articles described herein.

[0085] 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 non-fixed area 25 and the fixed area 21 and their ranges 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 dynamic friction coefficient 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.

[0086] 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 with 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 part 4 from spilling. If such viewpoints are considered important, the anti-slip portion 9b may be configured to overlap with 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.

[0087] 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.

[0088] In addition to the configuration shown in Figure 7, which lacks a fixed area 21 in the rear region R, a configuration in which there is a fixed area 21 in the rear region R but not in the front region F is also conceivable. In this case, the non-skin side surface of the backsheet 2 in the front region F can be made smoother, improving the function of the anti-slip portion 9b formed in the front region F and preventing the front region F from shifting away from the underwear. Opposite the front region F is the relatively flat front of the body, so the front region F is less prone to deformation and therefore less likely to shift away from the underwear. However, once it does shift, it is an area that can easily cause significant discomfort, so preventing the front region F from shifting away from the underwear is also important.

[0089] 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.

[0090] <About the manufacturing process> Figure 8 illustrates a part of the process in the manufacturing method of an 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. The planned cutting contour (dotted line) of the absorbent article 1 is set on the backsheet strip 2Z. 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 that an unfixed region 25 is later formed. 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.

[0091] 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 conveying 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.

[0092] After applying the adhesive, the absorbent section 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 if necessary, cut to obtain the absorbent article 1 (Figure 1, etc.). In Figure 8, the arrangement of the anti-slip section 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 section 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 section 4, the top sheet strip, and the side sheet strip) can be laminated with the adhesive.

[0093] 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 backsheet 2 to be more securely fixed to the underwear, making it easier for the backsheet 2 and the skin-side structure 15 to slide relative to each other, thus improving the wearing comfort.

[0094] 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. [Examples]

[0095] The embodiments of this disclosure will be described in more detail below with reference to examples.

[0096] <Preparation of absorbent materials> (Example 1) As Example 1, a commercially available conventional product P (manufactured by Daio Paper Corporation, 23 cm with wings) 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, with adhesive 8 placed over the entire surface of the backsheet, fixing the backsheet and the structure on top of it (skin-side structure), so that the backsheet and the skin-side structure cannot slide relative to each other with the normal force of the user.

[0097] (Example 2) The basic structure of the conventional product P in Example 1 is the same, and the arrangement of the anti-slip parts is also the same, but a sanitary napkin with a non-fixed area was prepared. The sanitary napkin in Example 2 had the same arrangement of fixed areas as described with reference to Figures 1 to 3.

[0098] <Method for measuring the coefficient of friction> For each example, the measurement area was defined as a region measuring 10 mm in the horizontal direction and 50 mm in the front-to-back direction, within the central area of ​​the non-skin side of the backsheet of the sanitary napkin, specifically the area where the absorbent portion overlaps and where no anti-slip portion is provided (the area outside the outermost lateral edge of the anti-slip portion located laterally). This 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. For Example 1, a test piece consisting of the backsheet 2, adhesive, and covering sheet 4b was extracted, while for Example 2, a test piece consisting of the backsheet 2 and covering sheet 4b stacked on top of each other was extracted.

[0099] 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.

[0100] <Results and Discussion> The average of the average deviations of the coefficients of dynamic friction was 0.572 in Example 1 and 0.524 in Example 2. Thus, the average deviation of the coefficients of dynamic friction in Example 2 was smaller than that of Example 1. Furthermore, when the measured parts of each example were visually observed and compared, numerous wrinkles were observed in the back sheet in Example 1, while almost no wrinkles were observed in the back sheet in Example 2.

[0101] 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 assumed that the measured value of the coefficient of dynamic friction in the fixed area of ​​Example 2 is 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 of ​​Example 1 and the mean deviation (MMD) of the coefficient of dynamic friction in the fixed area. 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%.

[0102] 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. [Explanation of Symbols]

[0103] 1. Absorbent articles 2 back seats 3 Top Sheet 4 Absorbent part 4a Absorbent body 4b Packaging sheet 7 Side Seats 8. Adhesive 8a Side adhesive 8b Main body adhesive 9b Anti-slip part for the main body (anti-slip part) 9w Wing anti-slip section 15 Skin side structure 21 Fixed area 25 Non-fixed area bd Absorbent Article Body C central area CL Anteroposterior center line D1 Front-to-back direction (longitudinal direction) D2 Horizontal direction (short side direction) Dt Conveying direction F Anterior area Q Opposite 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, The skin-side structure includes an absorbent portion directly positioned on the skin side of the back sheet and a permeable top sheet positioned on the skin side of the absorbent portion. The back sheet and the skin-side structure are not fixed together, and the back sheet and the skin-side structure are relatively slidable in a non-fixed region, and the fixed region is other than the non-fixed region. An absorbent article 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 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 drainage port that faces the body fluid drainage port of the wearer when worn, a front region in front of the central region, and a rear region behind the central region. The absorbent article according to claim 1, wherein 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 between 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 fixed area is formed to overlap the front end and rear end of the absorbent portion.

6. On the non-skin side of the backsheet, anti-slip portions for securing the absorbent article to the underwear during wear are provided in the front region, the central region, and the rear region. The absorbent article according to claim 2 or 3, wherein in the front region or the rear region, the anti-slip portion does not overlap with the fixed 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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