Body fluid absorbent articles

Abstract

To provide a body fluid absorbent article capable of enhancing absorptivity of a body fluid with an absorber and suppressing the reversion of the body fluid from the absorber.SOLUTION: A body fluid absorbent article 1 comprises a top sheet 2, a back sheet 3, and an absorber 4 disposed between the top sheet 2 and the back sheet 3, and absorbs with the absorber 4 a body liquid transmitted through the top sheet 2 on a side to be in contact with a user's skin. Recess unit patterns 12 recessed toward the absorber 4 side are repetitively arranged in the longitudinal direction and the cross direction of the top sheet 2 to form a plurality of recesses 9 in the top sheet 2, and the aperture area rate of the recesses 9 in the top sheet 2 is 4% or more but 10% or less.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a body fluid absorbent article used to absorb body fluids such as vaginal discharge, menstrual blood, sweat, and urine. [Background technology]

[0002] Body fluid absorbent articles have traditionally been used to absorb body fluids such as vaginal discharge, menstrual blood, sweat, urine, etc. Body fluid absorbent articles typically have a three-layer structure including a top sheet that is permeable to body fluids, a back sheet that is impermeable to body fluids, and an absorbent body sandwiched between the top sheet and the back sheet.The top sheet is in contact with the user's skin, and the absorbent body absorbs body fluids that have permeated the top sheet.

[0003] In order to improve comfort when using a bodily fluid absorbent article, it is important to increase the absorbency of bodily fluids by the absorbent core and to minimize the amount of bodily fluid remaining on the top sheet that comes into contact with the skin, so that bodily fluids do not come into contact with the user's skin. As a means for achieving this, a technique has been disclosed in which multiple recesses are formed in the top sheet by embossing or the like (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-014927 Summary of the Invention [Problem to be solved by the invention]

[0005] In absorbent articles, the absorption of body fluids by the absorbent body is improved by forming many recesses in the top sheet, but in order to increase comfort when using the absorbent article, it is also necessary to prevent body fluids from flowing back out of the absorbent body.

[0006] The present invention has been made to solve this problem, and aims to provide a body fluid absorbent article that can improve the absorbency of body fluids by the absorbent body and suppress the return of body fluids from the absorbent body. [Means for solving the problem]

[0007] The present invention relates to a body fluid absorbent article comprising a top sheet, a back sheet, and an absorbent body disposed between the top sheet and the back sheet, wherein the absorbent body absorbs body fluid that has permeated through the top sheet on the side that contacts the user's skin. The body fluid absorbent article of the present invention is characterized in that a plurality of recesses are formed in the top sheet by repeatedly arranging unit patterns of recesses recessed toward the absorbent body in the longitudinal and lateral directions of the top sheet, and the open area ratio of the recesses in the top sheet is 4% to 10%.

[0008] Preferably, the body fluid absorbent article of the present invention can be configured such that a plurality of unit rows, each formed by a unit pattern of the recesses being repeatedly arranged in a direction inclined relative to the vertical or horizontal direction of the top sheet, are arranged parallel to each other.

[0009] In addition, in the body fluid absorbent article of the present invention, preferably, the top sheet has a vertically elongated shape in which the length in the vertical direction is longer than the length in the horizontal direction, and the unit pattern of the recesses can be configured to be repeatedly arranged in a direction inclined relative to the horizontal direction.

[0010] Furthermore, in the body fluid absorbent article of the present invention, preferably, the top sheet has a vertically elongated shape in which the length in the vertical direction is longer than the length in the horizontal direction, and the unit pattern of the recesses can be configured so that they are repeatedly arranged in a direction inclined relative to the vertical direction.

[0011] Furthermore, in the body fluid absorbent article of the present invention, it is preferable that the top sheet has a plurality of dense regions in which a plurality of the recesses are gathered, and each of the plurality of dense regions is surrounded by a sparse region in which no recesses are formed. [Effects of the Invention]

[0012] According to the body fluid absorbent article of the present invention, the absorbency of body fluids by the absorber can be improved, and backflow of body fluids from the absorber can be suppressed. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a plan view of the body fluid absorbent article. [Figure 2] FIG. [Figure 3] FIG. 2 is an enlarged longitudinal cross-sectional view showing a schematic configuration of a portion of the body fluid absorbent article. [Figure 4] FIG. 10 is an enlarged longitudinal cross-sectional view showing a schematic configuration of a portion of a modified top sheet. [Figure 5] FIG. 2 is an enlarged plan view of a portion of the top sheet. [Figure 6] FIG. 4 is an explanatory diagram showing a unit pattern of recesses. [Figure 7] FIG. 2 is a plan view of the absorbent article, illustrating the arrangement of a plurality of recesses in the top sheet. [Figure 8] FIG. 2 is an explanatory diagram showing a schematic configuration of a method for forming a plurality of recesses in a first raw material sheet that is the base of a top sheet. [Figure 9] FIG. 2 is a perspective view showing a schematic configuration of a pair of printing rolls. [Figure 10] 4A and 4B are diagrams illustrating the arrangement of a plurality of protrusions formed on the outer peripheral surface of a printing roll. [Figure 11] 3A and 3B are diagrams illustrating an arrangement of a plurality of recesses formed in a first raw material sheet. [Figure 12] 1 is an explanatory diagram showing a schematic configuration of a method for manufacturing a body fluid absorbent article. DETAILED DESCRIPTION OF THE INVENTION

[0014] Body fluid absorbent articles are attached directly to a user's clothing (e.g., underwear) or skin and are used to absorb body fluids such as vaginal discharge, menstrual blood, sweat, urine, etc. Specific examples of body fluid absorbent articles include panty liners, sanitary napkins, incontinence pads, underarm sweat pads, and sweat-absorbing sheets.

[0015] The absorbent article has at least a three-layer structure including a top sheet that is permeable to body fluids, a back sheet that is impermeable to body fluids, and an absorbent body sandwiched between the top sheet and the back sheet that can absorb body fluids. The absorbent body absorbs and retains body fluids that permeate the top sheet on the side that comes into contact with the user's skin. The back sheet prevents body fluids from leaking from the absorbent body and adhering to the user's clothing during use.

[0016] An embodiment of the present invention will be described below with reference to the accompanying drawings. In the following embodiment, the side of the absorbent article that comes into contact with the user's skin is referred to as the "front side," and the opposite side is referred to as the "back side."

[0017] Overall structure of the body fluid absorbent article The bodily fluid absorbent article 1 of this embodiment is a panty liner that is attached to a user's underwear during use. As shown in Figures 1 to 3, the bodily fluid absorbent article 1 has a flat shape with a front and back principal surfaces, and includes a top sheet 2, a back sheet 3, and a sheet-like absorbent body 4 sandwiched between the top sheet 2 and the back sheet 3. The top sheet 2, the back sheet 3, and the absorbent body 4 are all formed to the same outer shape (shape defined by the outer periphery) and size, and correspond to the outer shape and size of the bodily fluid absorbent article 1. Note that the absorbent body 4 does not necessarily have to have the same outer shape and size as the top sheet 2 and the back sheet 3; for example, it may have the same outer shape as the top sheet 2 and the back sheet 3 but be slightly smaller in size (for example, it may be small enough to fit inside the pressure-bonding portions 6 described below).

[0018] The body fluid absorbent article 1 is formed by laminating a top sheet 2, an absorbent body 4, and a back sheet 3 in this order from the front side to the back side, with the top sheet 2 and the absorbent body 4 being fixed over the entire surface or almost the entire surface by an adhesive layer 5, and the absorbent body 4 and the back sheet 3 being fixed over the entire surface or almost the entire surface by an adhesive layer 6. An adhesive layer 7 is provided on the back surface of the back sheet 3 for attaching the body fluid absorbent article 1 to the user's underwear.

[0019] The outer peripheral edge of the absorbent article 1 is subjected to heat bonding, ultrasonic bonding, or simple bonding in which pressure is applied only in the thickness direction, along the entire periphery, to form a pressure-bonded portion 8. In the pressure-bonded portion 8, the top sheet 2, absorbent body 4, and back sheet 3 are strongly bonded together, or the top sheet 2 and back sheet 3 are strongly bonded together, and the thickness of the pressure-bonded portion 8 is thinner than the thickness of the portions other than the pressure-bonded portion 8. There are no particular restrictions on the width of the pressure-bonded portion 8, but it is preferably 2 mm or more and 5 mm or less extending inward from the outer peripheral edge of the absorbent article 1. It should be noted that the pressure-bonded portion 8 does not necessarily have to be formed on the absorbent article 1.

[0020] The absorbent article 1 preferably has an outer shape that matches the part of the user's body where it is to be applied during use, and in this embodiment, it has a vertically elongated shape that matches the user's crotch area. That is, in a plan view, the absorbent article 1 has a length in the vertical direction, which is oriented along the front-to-back direction of the user's body, that is longer than a length in the horizontal direction, which is perpendicular to the vertical direction, and the vertical direction is the length direction, and the horizontal direction is the width direction. Here, the vertical direction of the absorbent article 1 is the direction that serves as a reference when applying the absorbent article 1 to a specific part of the user in an appropriate orientation during use.

[0021] Furthermore, although not particularly limited, the absorbent article 1 has a bilaterally symmetrical shape with respect to a center line that bisects the widthwise dimension and extends in the longitudinal direction. The absorbent article 1 may or may not be symmetrical from front to back with respect to the center line that bisects the lengthwise dimension and extends in the widthwise direction. Furthermore, although not particularly limited, the absorbent article 1 is formed so that its width is narrowest at the center in the longitudinal direction, and the left and right side edges gradually become narrower from the front and rear ends toward the center.

[0022] The external shape of the body fluid absorbent article 1 can be various shapes such as a track (circular track) of a stadium or a shape similar to this, an oval shape, a rectangle, etc., if it is not vertically elongated, it can be various shapes such as a square shape, a circle shape, a polygon shape, etc.

[0023] The size and thickness of the bodily fluid absorbent article 1 are not particularly limited, and can be appropriately set depending on the part of the user to which it is applied during use.

[0024] The body fluid absorbent article 1 does not necessarily have to have a three-layer structure of a top sheet 2, an absorbent body 4, and a back sheet 3, but may have a laminated structure of four or more layers, for example, by providing a sheet between the top sheet 2 and the absorbent body 4 that has a liquid-permeable effect, a diffusing effect, or the effect of preventing body fluids from flowing back to the surface side.

[0025] Top sheet The top sheet 2 comes into contact with the user's skin during use and allows bodily fluids excreted in the top sheet 2 to pass through in the thickness direction and transfer to the absorbent body 4; it has liquid permeability that allows bodily fluids to pass through. The top sheet 2 is not particularly limited in terms of its structure as long as it is liquid permeable, and examples of such sheet structures include woven fabrics, knitted fabrics, nonwoven fabrics, and felt. Among these, it is preferable to use a nonwoven fabric for the top sheet 2 in terms of its pleasant feel and low irritation to the skin. The nonwoven fabric used for the top sheet 2 may be manufactured by any conventional method without any particular limitation, but is preferably manufactured by a method such as the spunlace method, thermal bond method, air-through method, air-laid method, needle punch method, or spunbond method. These methods not only improve the texture of the top sheet 2, but also increase safety for the skin because no adhesives or solvents are used.

[0026] The material constituting the top sheet 2 is not particularly limited, and examples include natural fibers such as cotton, silk, pulp, wool, and hemp; synthetic fibers such as polyester, polyamide, acrylic, polypropylene, polyethylene / polyester composite, and polyethylene / polypropylene composite; semi-synthetic fibers such as rayon and acetate; and fibers made by mixing various fibers (blended spinnings and mixed fiber products). Among these, cellulosic fibers such as cotton, rayon, and acetate have excellent moisture absorption properties, allowing the skin surface to maintain an appropriate level of moisture. The fibers themselves absorb moisture and become soft, resulting in less friction with the skin and minimal static electricity. In particular, using cotton, a natural fiber, as the cellulosic fiber is pleasant to the touch and less irritating to the skin (less likely to cause rashes), making the body fluid absorbent article 1 gentle on the skin and highly comfortable to use.

[0027] If the top sheet 2 is made of 100% cotton, the bodily fluid absorbent article 1 can be made more effectively gentle on the skin and highly comfortable to wear. On the other hand, if the top sheet 2 is made of cotton and thermoplastic synthetic fibers such as polyethylene / polyester bicomponent fibers, when the bodily fluid absorbent article 1 is subjected to a thermocompression process to form the pressure-bonded portions 8, the thermoplastic synthetic fibers melt and can weld the top sheet 2 to the absorbent body 4 (containing thermoplastic fibers) or the back sheet 3. In this case, it is preferable that the top sheet 2 contain 50% or more cotton, from the perspective of improving the aforementioned gentleness to the skin.

[0028] The top sheet 2 does not have to be composed of a single liquid-permeable sheet, but may be composed of a laminate of multiple liquid-permeable sheets. In this case, the top sheet 2 is preferably composed of a laminate in which a sheet made of cellulosic fiber (preferably cotton) is placed on the side that comes into contact with the user, and a sheet made of thermoplastic synthetic fiber is placed on the side that comes into contact with the absorbent core 4.

[0029] As shown in Fig. 1, the top sheet 2 has a plurality of recesses 9 formed on its surface side. The recesses 9 need only be formed in at least the main bodily fluid discharge region F of the top sheet 2, but may also be formed over the entire top sheet 2 as in this embodiment. The entire top sheet 2 refers to the entire region excluding the pressure-bonded portions 8. The main bodily fluid discharge region F refers to the region facing the private parts from which the user discharges bodily fluids during use, and in this embodiment, it is the approximate center region in the longitudinal direction of the top sheet 2, as indicated by the dashed-dotted line in Fig. 1. The position and size of the main bodily fluid discharge region F may be adjusted as appropriate depending on the part of the user to which the absorbent article 1 is applied and the manner in which it is worn on that part, and are not particularly limited.

[0030] The multiple recesses 9 are formed by, for example, embossing the top sheet 2, as will be described in detail later. As shown in Figure 3, the depressions 9 of the top sheet 2 are made thinner by the pressing force applied during embossing, making it easier for body fluids to pass through the depressions 9. Therefore, body fluids discharged into the top sheet 2 are transferred to and absorbed by the absorbent body 4 mainly via the depressions 9. The body fluids absorbed into the absorbent body 4 spread radially in the surface direction of the absorbent body 4 and are retained by the absorbent body 4.

[0031] As shown in Figure 3, the recess 9 has a tapered shape in a longitudinal cross section parallel to the thickness direction of the top sheet 2, with the width gradually narrowing toward the bottom of the recess 9. The recess 9 has a tapered shape in longitudinal cross section in all directions, and the shape in cross section gradually becomes smaller from the opening 90 side that widens on the surface of the top sheet 2 toward the bottom 91 side. In this embodiment, the recess 9 has a truncated cone shape with a flat tip that forms the bottom 91.

[0032] The shape of the recess 9 in vertical cross section is not particularly limited as long as it is tapered, and may be, for example, a cone shape with a rounded or pointed tip forming the bottom 91 (not shown). As shown in FIG. 4(A), the peripheral wall 92 may be inclined in a curved shape rather than a straight line, or as shown in FIG. 4(B), the peripheral wall 92 may be inclined in two or more stages. In this way, the shape of the recess 9 in vertical cross section can be various shapes as long as it is tapered. Furthermore, the recess 9 may have a hole (not shown) formed in the bottom 91.

[0033] The recesses 9 have a shape that tapers overall toward the bottom 91, and because the shape is large in cross section on the side of the openings 90 that widen on the surface of the top sheet 2, body fluid discharged into the top sheet 2 can be smoothly transferred from the recesses 9 to the absorbent body 4, improving the absorption of body fluid by the absorbent body 4. In addition, because the shape of the cross section on the bottom 91 side of the recesses 9 that are close to the absorbent body 4 is small, body fluid held by the absorbent body 4 can be prevented from flowing back from the absorbent body 4 to the top sheet 2 side via the recesses 9.

[0034] The depth of the recesses 9 is not particularly limited, but as shown in Figure 3, it is preferable that the recesses 9 protrude beyond the thickness of the top sheet 2 toward the absorbent body 4. By having the recesses 9 protrude toward the absorbent body 4, bodily fluids can be transferred more smoothly to the absorbent body 4, and the absorbency of bodily fluids by the absorbent body 4 can be further improved.

[0035] The shape of the recesses 9 in plan view is not particularly limited, and may be circular as in this embodiment, or may be elliptical or polygonal. The area of ​​the recesses 9 in plan view (the area of ​​the openings of the recesses 9 on the surface of the top sheet 2, hereinafter referred to as "opening area") is not particularly limited, but if it is too small, the effect of the recesses 9 in smoothly transferring body fluids to the absorbent body 4 will be weakened, while if it is too large, body fluids will easily return from the absorbent body 4. Therefore, the opening area of ​​the recesses 9 should be 0.2 mm 2 Over 7.1mm 2 It is preferable that the thickness is less than 0.4 mm. 2 Over 1.8mm 2 It is more preferable to set the following:

[0036] There are no particular limitations on the total open area of ​​the recesses 9 in the top sheet 2, but if it is too small, the effect of the recesses 9 in smoothly transferring bodily fluids to the absorbent body 4 will be weakened, while if it is too large, the adhesive of the adhesive layer 5 that bonds the top sheet 2 and the absorbent body 4 together will come into contact with the skin, reducing comfort during use of the bodily fluid absorbent article 1. For this reason, the total open area of ​​the recesses 9 in the top sheet 2, expressed as a ratio (open area ratio) to the area of ​​the top sheet 2 (area of ​​the region excluding the compression-bonded portions 8), is preferably 4% to 10%, and more preferably 5% to 8%. This open area ratio may be 4% to 10%, and more preferably 5% to 8%, at least in the main bodily fluid discharge region F of the top sheet 2.

[0037] As will be described later, when multiple recesses 9 are formed in the top sheet 2 by arranging multiple unit rows 13, each of which is made up of a unit pattern 12 of recesses repeatedly arranged in a direction inclined relative to the vertical or horizontal direction of the top sheet 2, parallel to each other, the ratio (opening area rate) of the total opening area of ​​the recesses 9 in the unit pattern 12 to the area of ​​the unit pattern 12 of recesses is preferably 4% or more and 10% or less, more preferably 5% or more and 8% or less.

[0038] This opening area ratio can be calculated by taking a photograph of the surface of the top sheet 2 with a camera while placing a scale, importing the photographed image into a computer, extracting the entire area of ​​the top sheet 2 (the area of ​​the unit pattern 12 of the recess) using image analysis software to measure its area S1, and extracting the openings 90 of multiple recesses 9 within the entire area of ​​the top sheet 2 (the area of ​​the unit pattern 12 of the recess) to measure their total area S2, and then calculating the opening area ratio by 100 × S2 / S1.

[0039] As shown in FIG. 1 , the recesses 9 are not uniformly arranged on the top sheet 2. That is, the recesses 9 are not arranged on the top sheet 2 in an evenly dispersed manner, such as in a grid or staggered pattern. The recesses 9 are arranged on the top sheet 2 in a manner where some recesses 9 are clustered together at multiple locations on the top sheet 2. That is, at least in the main bodily fluid discharge region F, and in this embodiment, throughout the entire top sheet 2, as shown in FIG. 5 , the top sheet 2 includes multiple dense regions 10 in which the recesses 9 are densely packed, and the multiple dense regions 10 are spaced apart. The multiple dense regions 10 are sandwiched by sparse regions 11, and each dense region 10 is surrounded by the sparse regions 11. Here, the sparse regions 11 refer to regions of the top sheet 2 where no recesses 9 are formed. The number of recesses 9 in a dense region 10 is not particularly limited, but is preferably three or more, and more preferably four or more. Furthermore, it is preferable that the multiple recesses 9 in a dense region 10 are not gathered in a line but are evenly scattered and gathered together. The top sheet 2 may include portions other than the dense regions 10 and the sparse regions 11, and for example, one recess 9 may be arranged alone, away from the recess 9 in the dense region 10.

[0040] Because the top sheet 2 has multiple dense regions 10 sandwiched between sparse regions 11, body fluid discharged onto the top sheet 2 spreads along the sparse regions 11 in the plane direction of the top sheet 2 and is guided to the multiple dense regions 10 present in the top sheet 2. Once guided to the dense regions 10, the body fluid is quickly transferred to the absorbent body 4 by the multiple closely packed recesses 9 within the dense regions 10, and is absorbed by the absorbent body 4. In this way, the body fluid discharged onto the top sheet 2 is diffused over a wide range, and during the diffusion process, the body fluid is quickly transferred to the absorbent body 4 in each of the dense regions 10. This allows the body fluid to be absorbed over a wide range in the absorbent body 4, allowing the absorbent body 4 to absorb a larger amount of body fluid, while also preventing the body fluid from flowing back from the absorbent body 4 into the top sheet 2.

[0041] In the dense region 10, a plurality of recesses 9 are gathered at small intervals within an imaginary frame of a predetermined shape in a plan view. In the present embodiment, as shown in Fig. 5, the top sheet 2 includes, as the dense region 10, a dense region 10A in which four recesses 9 are gathered within a circular imaginary frame, and dense regions 10B1, 10B2, 10B3, and 10B4A in which 17 recesses 9 are gathered within a circular imaginary frame, and a predetermined number of recesses 9 are evenly scattered within each dense region 10. The distance between the recesses 9 within the dense region 10, measured from the center to the nearest recess 9, is 1.5 mm or more and 3.0 mm or less, and preferably 2.0 mm or more and 2.8 mm or less.

[0042] The size of the dense region 10 is not particularly limited, but in this embodiment, the size of the circular imaginary frame in which the multiple recesses 9 are accommodated is set to a diameter in the range of 5 mm to 20 mm. The shape of the imaginary frame does not necessarily have to be circular, and may be various shapes such as an ellipse or a rectangular shape such as a square or rectangle. When the imaginary frame is elliptical, its size is set to a major axis in the range of 10 mm to 20 mm and a minor axis in the range of 5 mm to 15 mm. When the imaginary frame is square or rectangular, the size is the same as when it is circular or elliptical, respectively.

[0043] There are no particular limitations on the density of the multiple recesses 9 contained in the dense region 10, but if the density is too small, the effect of the multiple recesses 9 in the dense region 10 in quickly transferring body fluids to the absorbent body 4 will be weakened, while if the density is too large, the adhesive of the adhesive layer 5 that bonds the top sheet 2 and the absorbent body 4 together will come into contact with the skin, reducing comfort during use of the body fluid absorbent article 1. Therefore, the density of the multiple recesses 9 contained in the dense region 10, in terms of the ratio of the open area of ​​the recesses 9 to the area of ​​the dense region 10 (open area rate), is preferably 8% to 15%, and more preferably 10% to 13%.

[0044] The opening area ratio of the recesses 9 in the dense region 10 can be calculated by taking a photograph of the surface of the top sheet 2 with a camera while placing a scale on it, importing the photographed image into a computer, extracting the dense region 10 using image analysis software and measuring its area S3, and extracting the openings 90 of the multiple recesses 9 in the dense region 10 and measuring their total area S4, and then calculating the opening area ratio by 100 × S4 / S3.

[0045] Additionally, in the dense regions 10 of the top sheet 2, the presence of multiple recesses 9 tends to reduce the adhesive strength of the adhesive layer 5 between the top sheet 2 and the absorbent body 4. In particular, when the material of the top sheet 2 is primarily composed of hydrophilic cellulosic fibers such as cotton or rayon, adhesive strength tends to decrease when the adhesive used in the adhesive layer 5 is primarily composed of a hydrophobic rubber-based hot melt. However, when sparse regions 11 are present in the top sheet 10 so as to surround the dense regions 10, the adhesive strength of the adhesive layer 5 between the top sheet 2 and the absorbent body 4 is high in the sparse regions 11, making it possible for the top sheet 2 to be less likely to peel from the absorbent body 4. In this way, the presence of sparse regions 11 around each of the multiple dense regions 10 in the top sheet 2 allows the top sheet 2 to maintain high resistance to peeling from the absorbent body 4 while improving the absorbency of body fluids by the absorbent body 4.

[0046] The size of the sparse region 11 is not particularly limited, but is preferably large enough to separate the dense regions 10 sandwiching the sparse region 11 by, for example, a distance of 5 mm to 10 mm. Furthermore, the total area of ​​the sparse region 11 in a planar view is not particularly limited, but if it is too small, it will be less effective at spreading body fluid discharged onto the top sheet 2 in the plane direction of the top sheet 2 and at increasing the durability of the top sheet 2 against peeling from the absorbent body 4, while if it is too large, it will be less effective at causing the dense region 10 to quickly transfer body fluid to the absorbent body 4. For this reason, the area of ​​the sparse region 11 in a planar view, expressed as a ratio (area ratio of the sparse region) of the area of ​​the top sheet 2 (area of ​​the region excluding the compression-bonding portions 8), is preferably 20% to 50%, and more preferably 30% to 40%.

[0047] The area ratio of the sparse region 11 can be determined by taking a photograph of the surface of the top sheet 2 with a camera while placing a scale, importing the photographed image into a computer, extracting the main body fluid discharge region F using image analysis software and measuring its area S1, and also extracting the dense region 10 and any independently existing recesses 9 within the main body fluid discharge region F and measuring the area S5 of the remaining areas, and then calculating the opening area ratio by 100 × S5 / S1.

[0048] As shown in Fig. 6, the plurality of recesses 9 in the top sheet 2 described above are formed on the top sheet 2 by arranging a plurality of unit rows 13 in parallel to one another, each row being made up of a repeating unit pattern 12 of recesses. A unit pattern 12 of recesses is made up of one or more recesses 9, and when made up of a plurality of recesses 9, it is a combination of recesses that forms a predetermined pattern. In this embodiment, as shown in Fig. 7, the unit pattern 12 is made up of 32 (=8 × 4) recesses 9 that make up the eight dense regions 10A described above, and 68 (4 × 17) recesses 9 that make up the four dense regions 10B1, 10B2, 10B3, and 10B4, for a total of 110 recesses 9. These unit patterns 12 of recesses are repeatedly arranged along the vertical direction (lengthwise direction) and horizontal direction (widthwise direction) of the top sheet 2, as shown in Fig. 6, thereby forming a plurality of recesses 9 in the top sheet 2.

[0049] The shape of recessed portion unit pattern 12 is not limited to the shape of this embodiment, and may be a shape combining multiple recessed portions 9 in a simpler pattern. For example, in this embodiment, the patterns of recessed portions 9 in dense regions 10B1, 10B2, 10B3, and 10B4 are slightly different, but the patterns of recessed portions 9 in dense regions 10B3 and 10B4 may be made the same as the patterns of recessed portions 9 in dense regions 10B1 and 10B2, and recessed portion unit pattern 12 having a shape including four dense regions 10A and two dense regions 10B1 and 10B2 may be repeatedly arranged, or the patterns of recessed portions 9 in dense regions 10B2, 10B3, and 10B4 may be made the same as the pattern of recessed portions 9 in dense region 10B1, and recessed portion unit pattern 12 having a shape including two dense regions 10A and one dense region 10B1 may be repeatedly arranged.

[0050] Although there are no particular limitations on the unit patterns 12 of the recesses, in this embodiment, they are not repeatedly arranged in a direction parallel to the horizontal direction, which is the width direction of the top sheet 2, but are repeatedly arranged in a direction inclined relative to the horizontal direction. The inclination angle θ of the direction in which the unit patterns 12 are repeatedly arranged relative to the horizontal direction of the top sheet 2 is not particularly limited, but is preferably 1.0° to 5.0°, and more preferably 2.5° to 3.5°. In this embodiment, the unit patterns 12 of the recesses are also repeatedly arranged in a direction inclined relative to the vertical direction, which is the longitudinal direction of the top sheet 2, rather than repeatedly arranged in a direction parallel to the vertical direction. Note that the unit patterns 12 of the recesses may be repeatedly arranged in a direction parallel to the vertical direction of the top sheet 2. Alternatively, the unit patterns 12 of the recesses may be repeatedly arranged in a direction parallel to the horizontal direction of the top sheet 2, and repeatedly arranged in a direction inclined relative to the vertical direction of the top sheet 2.

[0051] back seat The backsheet 3 prevents body fluids absorbed in the absorber 4 from leaking out from the back surface of the body fluid absorbent article 1 to the outside, and is liquid-impermeable so as to prevent body fluids from passing through. The material of the backsheet 3 is not particularly limited as long as it is liquid-impermeable, and examples thereof include liquid-impermeable films, liquid-impermeable nonwoven fabrics such as SMS, and spunbonded nonwoven fabrics and point-bonded nonwoven fabrics laminated with liquid-impermeable films. Examples of liquid-impermeable films include films made of polyethylene, polypropylene, polyester, nylon, polyvinyl alcohol, cellophane, vinyl chloride, etc., and multilayer films of these materials.

[0052] absorber The absorbent body 4 absorbs and retains the body fluids that have passed through the top sheet 2. The material of the absorbent body 4 is not particularly limited as long as it has the ability to absorb and retain body fluids, and examples of materials that can be used include well-known absorbent materials such as absorbent pulp and absorbent polymers that are commonly used in panty liners, sanitary napkins, sweat-absorbing sheets, etc.; and fiber assemblies with a sheet structure such as woven fabrics, knitted fabrics, nonwoven fabrics, or pulp products. Among these, it is preferable to use nonwoven fabrics made from natural and synthetic fibers because of their pleasant feel and excellent absorbency.

[0053] Examples of natural fibers include cotton, silk, pulp, wool, hemp, etc. Among these natural fibers, cellulosic fibers such as cotton and pulp (which do not contain protein components) are preferred because they are less likely to cause contact dermatitis such as allergies, are less likely to cause rashes, and have excellent absorbency.

[0054] Examples of synthetic fibers include nylon fibers, polyethylene fibers, polyester fibers, polyamide fibers, acrylic fibers, polyvinyl alcohol fibers, polypropylene fibers, polyethylene terephthalate fibers, ethylene vinyl acetate fibers, and urethane fibers. Semi-synthetic fibers such as rayon fibers, acetate fibers, and cupra fibers, as well as blends and mixed fibers of various fibers, can also be used. Among these, synthetic fibers such as ethylene vinyl acetate fibers, polypropylene fibers, polyethylene fibers, polyester fibers, and polyethylene terephthalate fibers, or composite fibers thereof, are preferred in terms of dry feel and texture. Examples of composite fibers include polyethylene / polyester (including polyethylene terephthalate) composite fibers, polyethylene / polypropylene composite fibers, and ethylene vinyl acetate / polypropylene composite fibers. These fibers may be used alone or in combination of two or more. An example of a combination of two or more fibers is a combination of cellulosic fibers and composite fibers, and the blending ratio can be, for example, 4:6 to 8:2.

[0055] The method for producing the nonwoven fabric used in the absorbent body 4 is not particularly limited and can be any conventionally known method, but among these, it is preferable to produce it by methods such as the spunlace method, thermal bond method, air-through method, air-laid method, needle punch method, spunbond method, etc. These methods not only improve the texture of the absorbent body 4, but also increase safety for the skin because no adhesives or solvents are used.

[0056] adhesive layer The adhesive layers 5, 6 are formed by, for example, applying or spraying a water-soluble adhesive (for example, an acrylic-based water-soluble adhesive) or a water-insoluble adhesive (for example, a rubber-based hot melt or a polyolefin-based hot melt) between the top sheet 2 and the absorbent body 4, and between the absorbent body 4 and the back sheet 3. The adhesive layers 5, 6 may be provided over the entire surface or almost the entire surface of the top sheet 2, the absorbent body 4, and the back sheet 3, or may be provided partially, for example, in a striped pattern (vertical stripes or horizontal stripes), a grid pattern, or a spiral pattern.

[0057] adhesive layer The adhesive layer 7 is formed, for example, by applying an adhesive to the back sheet 3. The adhesive is not particularly limited as long as it can attach the body fluid absorbent article 1 to clothing such as underwear, and for example, adhesives such as water-soluble adhesives (e.g., acrylic water-soluble adhesives) and water-insoluble adhesives (e.g., rubber-based hot melt, polyolefin-based hot melt) can be used. Among these, water-insoluble adhesives are preferred because they have superior adhesive strength to clothing such as underwear compared to other adhesives, and rubber-based hot melts are more preferred.

[0058] The adhesive layer 7 may be provided over the entire or almost the entire back surface of the back sheet 3, or may be provided partially. In this embodiment, as shown in Fig. 2, the adhesive layer 7 is configured by a plurality of strip-shaped adhesive portions 70 extending in the width direction of the back sheet 3 and arranged at predetermined intervals along the longitudinal direction of the back sheet 3, and the adhesive layer 7 is striped.

[0059] Before use, the adhesive layer 7 is protected by being covered with a release sheet (not shown), and at the time of use, the body fluid absorbent article can be attached to the user's skin or clothing such as underwear by peeling the release sheet from the adhesive layer 7. The release sheet is formed by applying a release agent to a sheet material such as a plastic film, a fiber sheet, or paper, and the release agent side is attached to the adhesive layer 7.

[0060] Method for manufacturing body fluid absorbent article A method for manufacturing the above-mentioned bodily fluid absorbent article 1 will now be described. First, with reference to Figures 8 to 11, a method for manufacturing a raw roll of a strip-shaped first raw sheet 101 that forms the top sheet 2 will be described. A manufacturing apparatus 110 in this manufacturing method includes a sheet supply unit 111 that supplies the first raw sheet 101, a recess forming unit 112 that forms a plurality of recesses 9 in the first raw sheet 101, and a sheet recovery unit 113 that recovers the first raw sheet 101 with the recesses 9 formed therein.

[0061] The sheet supply unit 111 includes a supply roll 114 around which the first raw sheet 101 is wound, and a support means (not shown) for rotatably supporting the supply roll 114. The first raw sheet 101 is unwound from the supply roll 114 by the rotation of a winding roll 121 (described later), and is transported to the recess forming unit 112 with its length direction as the transport direction.

[0062] The recess forming unit 112 includes a pair of printing rolls 115, 116 and a rotation drive means (not shown) that supports the pair of printing rolls 115, 116 and rotates them in synchronization with the conveyance of the first raw material sheet 101. The pair of printing rolls 115, 116 are arranged to sandwich the first raw material sheet 101 therebetween and rotate in opposite directions to each other in accordance with the conveyance direction of the first raw material sheet 101. The pair of printing rolls 115, 116 form recesses 9 in the first raw material sheet 101 by pressing protrusions 117 (described below) from one side of the first raw material sheet 101 passing between them without heating it. At this time, the protrusions 117 physically separate the fibers that make up the first raw material sheet 101 to form the recesses 9, and therefore, recesses 9 corresponding to the shape of the protrusions 117 are formed in the first raw material sheet 101.

[0063] As shown in Figures 9 and 10, a plurality of protrusions 117 are provided on the outer peripheral surface of one printing roll 115. The plurality of protrusions 117 are provided on the outer peripheral surface of the one printing roll 115 in an arrangement pattern corresponding to the arrangement pattern of the plurality of recesses 9 formed in the top sheet 2 described above. That is, unit rows 119 are formed by repeatedly arranging unit patterns 118 of protrusions in a direction inclined relative to the circumferential direction of the one printing roll 115, and a plurality of these unit rows 119 are arranged parallel to each other (aligned in the thickness direction of the one printing roll 115), thereby providing a plurality of protrusions 117 on the outer peripheral surface of the one printing roll 115. The inclination angle θ of the direction in which the unit patterns 118 are repeatedly arranged relative to the circumferential direction of the one printing roll 115 is the same as the inclination angle θ of the direction in which the unit patterns 12 of recesses of the top sheet 2 are repeatedly arranged relative to the lateral direction of the top sheet 2. The unit pattern 118 of protrusions has a pattern shape corresponding to the unit patterns 12 of recesses of the top sheet 2, and in this embodiment, is formed by a combination of a total of 110 protrusions 117.

[0064] The protrusions 117 have a tapered shape in a vertical cross section parallel to the height direction (the direction in which they protrude from the outer peripheral surface of one of the printing rolls 115), with the width gradually narrowing toward the tip. The protrusions 117 have a tapered vertical cross section in all directions, and in this embodiment, the protrusions 117 have a conical shape with a rounded tip. As a result, the recesses 9 in the top sheet 2 formed by the protrusions 117 have a tapered vertical cross section in all directions. The shape of the protrusions 117 is not particularly limited as long as the vertical cross section in all directions is tapered. The height of the protrusions 117 is not particularly limited, but is preferably greater than the thickness of the top sheet 2. As a result, as shown in FIG. 3 , the recesses 9 in the top sheet 2 formed by the protrusions 117 protrude beyond the thickness of the top sheet 2 toward the absorbent body 4.

[0065] As shown in Figure 9, a plurality of depressions 120 are formed on the outer peripheral surface of the other printing roll 116. The plurality of depressions 120 are formed on the outer peripheral surface of the other printing roll 116 in an arrangement pattern corresponding to the arrangement pattern of the plurality of protrusions 117 formed on the outer peripheral surface of the one printing roll 115, and when the other printing roll 116 rotates in synchronization with the one printing roll 115, the protrusions 117 of the one printing roll 115 fit into the corresponding depressions 120 of the other printing roll 116 with the first raw sheet 101 sandwiched therebetween. This allows the depressions 9 to be firmly and securely formed in the first raw sheet 101, improving the shape stability of the depressions 9.

[0066] As shown in Fig. 8, the first raw sheet 101 that has passed through the recess forming section 112 is transported to the sheet recovery section 113. The sheet recovery section 113 includes a take-up roll 121 and a transport drive means (not shown) that supports and rotates the take-up roll 121 to transport and wind the first raw sheet 101 onto the take-up roll 121. The first raw sheet 101 with the plurality of recesses 9 formed therein is transported to and wound up on the take-up roll 121. The first raw sheet 101 with the plurality of recesses 9 formed therein is stored in the form of a rolled raw web.

[0067] 11, the first raw sheet 101 having a plurality of recesses 9 formed therein has a plurality of unit rows 13 arranged parallel to each other in the CD direction (lined up in the width direction of the first raw sheet 101), each row being constituted by a unit pattern 12 of recesses repeatedly arranged in the MD direction (the length direction of the first raw sheet 101). The unit patterns 12 of recesses are not repeatedly arranged in a direction parallel to the MD direction, but are repeatedly arranged in a direction inclined relative to the MD direction. The inclination angle θ of the direction in which the unit patterns 12 are repeatedly arranged relative to the MD direction is preferably 1.0° to 5.0°, and more preferably 2.5° to 3.5°, similar to the top sheet 2.

[0068] In this way, the recess unit patterns 12 are not repeatedly arranged in a direction parallel to the MD, which provides the following effect. Specifically, if the recess unit patterns 12 are repeatedly arranged in a direction parallel to the MD, when the first raw sheet 101 is wound around the take-up roll 121 and one longitudinal portion of the first raw sheet 101 is stacked on top of another longitudinal portion, the recesses 9 in this portion will overlap from above with the recesses 9 arranged in the same unit row 13 in the other portion. If this occurs every time the first raw sheet 101 is wound around the take-up roll 121, the recesses 9 in each layer of the raw web may overlap, causing the shape of the recesses 9 to collapse (be crushed, deformed, etc.). This problem becomes more pronounced when the top sheet 2 is made primarily of cellulosic fibers such as cotton, as this results in poor shape stability of the top sheet 2.

[0069] In contrast, if the recess unit patterns 12 are repeatedly arranged in a direction inclined relative to the MD, when the first raw sheet 101 is wound around the take-up roll 121, even if one longitudinal portion of the first raw sheet 101 is stacked on top of another portion, there is no risk that the recesses 9 in this portion will overlap the recesses 9 arranged in the same unit row 13 in the other portion. Therefore, when the first raw sheet 101 is wound around the take-up roll 121 to form a raw web, the recesses 9 in each layer of the first raw sheet 101 will not overlap, and deformation of the shape of the recesses 9 (such as crushing or deformation) can be suppressed. In particular, when the material of the top sheet 2 is primarily composed of cellulose-based fibers such as cotton, the shape stability of the top sheet 2 is poor. Therefore, according to the method of this embodiment, the shape of the recesses 9 can be maintained when the first raw sheet 101, which is the basis of the top sheet 2, is stored in the form of a raw web.

[0070] In this embodiment, the unit patterns 12 of the recesses are also arranged in the CD direction, not in a direction parallel to the CD direction, but in a direction inclined relative to the CD direction. The unit patterns 12 of the recesses may also be arranged in a direction parallel to the CD direction.

[0071] Next, a manufacturing method for the body fluid absorbent article 1 will be described with reference to Fig. 12. A manufacturing apparatus 100 in this manufacturing method includes a sheet supply unit 105 that supplies a first raw material sheet 101 having a plurality of recesses 9 formed therein, a strip-shaped second raw material sheet 102 that will form the absorbent body 4, and a strip-shaped third raw material sheet 103 that will form the back sheet 3, a laminating unit 106 that laminates the raw material sheets 101, 102, and 103 into a strip-shaped laminated sheet 104, and a punching unit 107 that punches out the body fluid absorbent article 1 from the laminated sheet 104.

[0072] The sheet supply section 105 includes a first supply roll 105A around which the first raw sheet 101 is wound, a first transport drive means (not shown) that supports and rotates the first supply roll 105A to unwind and transport the first raw sheet 101 from the first supply roll 105A, a second supply roll 105B around which the second raw sheet 102 is wound, a second transport drive means (not shown) that supports and rotates the second supply roll 105B to unwind and transport the second raw sheet 102 from the second supply roll 105B, a third supply roll 105C around which the third raw sheet 103 is wound, and a third transport drive means (not shown) that supports and rotates the third supply roll 105C to unwind and transport the third raw sheet 103 from the third supply roll 105C. The first raw material sheet 101, the second raw material sheet 102, and the third raw material sheet 103 are synchronously transported from their respective supply rolls 105A, 105B, and 105C, and transported to the laminating section 106 with their length directions as the transport direction. Note that, during transport, the second raw material sheet 102 and the third raw material sheet 103 are coated with, for example, a hot melt adhesive using coaters 109A and 109B, respectively.

[0073] The laminating unit 106 includes a pair of heating rolls 106A and 106B, a laminating rotation drive means (not shown) that supports the pair of heating rolls 106A and 106B and rotates them in synchronization with the transport of the raw material sheets 101, 102, and 103, an embossing roll 106C and a backup roll 106D, and a crimping rotation drive means (not shown) that supports the embossing roll 106C and the backup roll 106D and rotates them in synchronization with the transport of the raw material sheets 101, 102, and 103. The pair of heating rolls 106A and 106B are arranged to sandwich the raw material sheets 101, 102, and 103 therebetween, and rotate in opposite directions to each other in accordance with the transport direction of the raw material sheets 101, 102, and 103. The embossing roll 106C and the backup roll 106D are disposed so as to sandwich the respective raw material sheets 101, 102, and 103 therebetween, and rotate in opposite directions to each other in accordance with the conveyance direction of the respective raw material sheets 101, 102, and 103.

[0074] The pair of heating rolls 106A, 106B applies heat and pressure to the raw material sheets 101, 102, and 103 passing between them, thereby bonding the raw material sheets 101, 102, and 103 to one another with a hot melt adhesive. This forms a strip-shaped laminated sheet 104 in which the raw material sheets 101, 102, and 103 are stacked. The laminated sheet 104 is supplied to an embossing roll 106C and a backup roll 106D located downstream.

[0075] The embossing roll 106C has a plurality of embossments (not shown) on its outer peripheral surface that correspond to the shapes of the pressure-bonded portions 8 of the body fluid absorbent article 1, and by embossing the laminated sheet 104 that passes between it and the backup roll 106D, a plurality of pressure-bonded portions 8 are formed on the laminated sheet 104. The laminated sheet 104 is then supplied to a punching section 107 located downstream.

[0076] The punching section 107 includes a cutting roll 107A having a blade shape (not shown) on its outer surface that corresponds to the outer shape of the body fluid absorbent article 1, a backup roll 107B that is arranged to sandwich the laminated sheet 104 between the cutting roll 107A and the backup roll 107B, and a rotational drive means (not shown) that supports the cutting roll 107A and the backup roll 107B and rotates them in synchronization with the transport of the laminated sheet 104.

[0077] The cutting roll 107A uses a blade to punch out shapes corresponding to the outer shapes of the absorbent articles 1 from the laminate sheet 104 as it passes between itself and the backup roll 107B, thereby separating the absorbent articles 1 one after another from the laminate sheet 104. In this embodiment, the absorbent articles 1 are punched out from the laminate sheet 104 so that the longitudinal direction (longitudinal direction) of the absorbent articles 1 is oriented in the CD direction (the width direction of the laminate sheet material 104). As a result, a plurality of recesses 9 are formed in the top sheet 2 of the absorbent article 1 such that the unit patterns 12 of the recesses are repeatedly arranged in a direction inclined relative to the lateral direction (width direction). Note that the absorbent articles 1 may also be punched out from the laminate sheet 104 so that the longitudinal direction (longitudinal direction) of the absorbent articles 1 is oriented in the MD direction (the length direction of the laminate sheet material 104). In this case, a plurality of recesses 9 are formed in the top sheet 2 of the absorbent article 1 such that unit patterns 12 of recesses are repeatedly arranged in a direction inclined relative to the vertical direction (longitudinal direction).

[0078] The separated individual absorbent articles 1 are transported to the next process by a transport conveyor 108, where an adhesive layer 6 is formed, and then the articles are individually packaged. Meanwhile, the trim 122, which is waste material of the laminated sheet 104 after the absorbent articles 1 are separated, is wound up on a cutting roll 107A and then collected.

[0079] Action and effect In the body fluid absorbent article 1 of this embodiment, the open area ratio of the recesses 9 in the top sheet 2 is 4% or more and 10% or less. This allows body fluid discharged into the top sheet 2 to be smoothly transferred to the absorbent body 4 by the multiple recesses 9, thereby improving the body fluid absorption by the absorbent body 4 and suppressing backflow of body fluid from the absorbent body 4. Furthermore, the adhesive of the adhesive layer 5, which bonds the top sheet 2 and the absorbent body 4 together, can be prevented from coming into contact with the user's skin, thereby improving comfort when using the body fluid absorbent article 1.

[0080] Furthermore, in the body fluid absorbent article 1 of this embodiment, a plurality of dense regions 10, each consisting of a group of recesses 9, are formed in the top sheet 2, and each of the dense regions 10 is surrounded by sparse regions 11 where no recesses 9 are formed. This allows body fluid discharged onto the top sheet 2 to be spread in the plane direction of the top sheet 2 by the sparse regions 11 and guided to the plurality of dense regions 10 dispersed in the top sheet 2, where the plurality of recesses 9 clustered closely together in the dense regions 10 allow the body fluid to be quickly transferred to the absorbent body 4 and absorbed by the absorbent body 4. Therefore, body fluid discharged onto the top sheet 2 can be quickly absorbed over a wide area of ​​the absorbent body 4, thereby improving the absorbency of body fluid by the absorbent body 4 and suppressing backflow of body fluid from the absorbent body 4. In addition, since the sparse regions 11 are present in the top sheet 10 so as to surround the dense regions 10, the adhesive strength of the adhesive layer 5 between the top sheet 2 and the absorbent body 4 is high in the sparse regions 11, making it difficult for the top sheet 2 to peel off from the absorbent body 4. In this way, by having sparse regions 11 around each of the multiple dense regions 10, the top sheet 2 can maintain high resistance to peeling of the top sheet 2 from the absorbent body 4 while improving the absorbency of body fluids by the absorbent body 4.

[0081] Furthermore, in the body fluid absorbent article 1 of this embodiment, the recesses 9 of the top sheet 2 have a tapered shape in longitudinal cross section, with the width gradually narrowing toward the bottom side (the absorbent body 4 side) of the recesses 9. As a result, the recesses 9 have a large shape in cross section on the side of the openings 90 that widen on the surface of the top sheet 2, allowing body fluid to smoothly transfer from the recesses 9 to the absorbent body 4. This improves the absorbency of body fluid by the absorbent body 4, reducing the amount of body fluid remaining in the top sheet 2 and preventing body fluid from coming into contact with the user's skin. In addition, because the recesses 9 have a small shape in cross section on the bottom 91 side that is close to the absorbent body 4, it is possible to prevent body fluid held by the absorbent body 4 from flowing back from the absorbent body 4 to the top sheet 2 side via the recesses 9.

[0082] Furthermore, in the body fluid absorbent article 1 of this embodiment, the recesses 9 of the top sheet 2 protrude beyond the thickness of the top sheet 2 toward the absorbent body 4. This makes it easier for body fluids discharged onto the top sheet 2 to migrate from the recesses 9 to the absorbent body 4. This further improves the body fluid absorption ability of the absorbent body 4.

[0083] Furthermore, in the manufacturing process of the absorbent article 1 of this embodiment, the plurality of recesses 9 are formed in the first raw sheet 101, which is the basis for the top sheet 2, by arranging multiple unit rows 13, each of which is formed by repeating unit patterns 12 of recesses in a direction inclined relative to the length direction of the sheet, in parallel to one another. As a result, when the first raw sheet 101, on which the plurality of recesses 9 have been formed, is wound around a take-up roll 121 and collected, the recesses 9 do not overlap in the respective wound layers of the first raw sheet 101. This prevents the shape of the recesses 9 from being distorted (such as crushed or deformed) when the first raw sheet 101 is wound around a take-up roll 121 and collected. In particular, when the material of the top sheet 2 is primarily composed of cellulose-based fibers such as cotton, the shape stability of the top sheet 2 is poor. However, according to this embodiment, the shape of the recesses 9 can be maintained when the first raw sheet 101, which is the basis for the top sheet 2, is stored in the form of a roll. Therefore, the shape of the plurality of recesses 9 formed in the top sheet 2 is also maintained in the absorbent article 1 manufactured using the first raw sheet 101.

[0084] Variations Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0085] In the above-described embodiment, as shown in Fig. 3, the recesses 9 protrude beyond the thickness of the top sheet 2 toward the absorbent body 4. In one variation, the recesses 9 may be recessed from the front surface side within the thickness of the top sheet 2, and may not protrude from the back surface side toward the absorbent body 4.

[0086] In the above-described embodiment, as shown in Fig. 3, the recess 9 has a tapered shape in a longitudinal cross section parallel to the thickness direction of the top sheet 2, with the width gradually narrowing toward the bottom side of the recess 9. As a variation, the recess 9 may not have a tapered shape in a longitudinal cross section parallel to the thickness direction of the top sheet 2, but may have a shape with a constant width from the opening 90 side to the bottom side 91.

[0087] In the above-described embodiment, as shown in Fig. 5, the top sheet 2 is formed with a plurality of dense regions 10 in which a plurality of recesses 9 are densely gathered. As a variation, the top sheet 2 may have a plurality of recesses 9 that are not densely gathered but are dispersed.

[0088] In the above-described embodiment, as shown in Figure 6, unit rows 13 are formed on the top sheet 2 by repeatedly arranging unit patterns 12 of recesses in a direction inclined relative to the longitudinal or lateral direction of the top sheet 2, and a plurality of unit rows 13 are arranged parallel to one another to form a plurality of recesses 9. As a variation, the unit patterns 12 of recesses may be repeatedly arranged in a direction parallel to the longitudinal direction of the top sheet 2 and also in a direction parallel to the lateral direction of the top sheet 2.

[0089] In the above-described embodiment, the body fluid absorbent article 1 is a panty liner, but as a variation, the body fluid absorbent article 1 can be used to absorb other types of body fluids, such as a sanitary napkin, an incontinence pad, an underarm sweat pad, or a sweat absorbing sheet. [Example]

[0090] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to the following examples.

[0091] To confirm the effect of the open area ratio of the recesses in the top sheet of a bodily fluid absorbent article, tests were conducted on the absorbency of bodily fluids by the absorbent core and the return of bodily fluids from the absorbent core. The bodily fluid absorbent articles used in Examples 1 to 3 and Comparative Examples 1 to 4 were composed of a laminated top sheet, absorbent core, and back sheet measuring 15 cm long x 5 cm wide, and the materials of the top sheet, absorbent core, and back sheet were as follows. The open area ratios of the recesses in the top sheets of Examples 1 to 3 and Comparative Examples 1 to 4 are shown in Table 1. Surface sheet: spunlace nonwoven fabric (same for all examples) Absorbent: Air-through nonwoven fabric (same for all examples) Backsheet: Polyethylene film (same for all examples)

[0092] The test involved first dripping 0.5 mL of a 0.62% mucin solution onto the top sheet and leaving it for 5 minutes. After 5 minutes, 10 sheets of filter paper measuring 7.5 cm x 7.5 cm were placed on top of the top sheet and left to stand in this state for 1 minute. After 1 minute, the 10 filter papers were removed from the top sheet and their weights were measured. The weight change M before and after placing the filter papers on the absorbent article was calculated, and the proportion of the mucin solution that had transferred from the absorbent article to the filter paper (100 x M / 0.5) was calculated. The specific gravity of the mucin solution was set to 1. The results are shown in Table 1. In addition, 10 pieces of filter paper were placed on the top sheet and left to stand for 1 minute, and a 378 g weight was placed on the filter paper. After leaving it in this state for 1 minute, the weights of the 10 pieces of filter paper were also measured, and the proportion of mucin aqueous solution that had transferred from the body fluid absorbent article to the filter paper (100 × M / 0.5) was calculated in the same manner. The results are shown in Table 1.

[0093] [Table 1]

[0094] According to Table 1, it was confirmed that when the open area ratio of the recesses in the top sheet is 4% or more, the absorbent body can absorb body fluids discharged into the top sheet well and can effectively prevent body fluids from flowing back out of the absorbent body. This means that the top sheet is less likely to stick to the skin when the body fluid absorbent article is used, improving comfort during use. [Explanation of symbols]

[0095] 1. Body fluid absorbing articles 2 Topsheet 3 Back Seat 4. Absorbent 9 Recess 10 dense area 11 Sparse Area 12 Recess unit pattern 13 Unit Pattern Unit Sequence

Claims

1. A body fluid absorbent article comprising a top sheet, a back sheet, and an absorbent body disposed between the top sheet and the back sheet, wherein the absorbent body absorbs body fluid that has permeated through the top sheet on the side that contacts the skin of a user, The top sheet and the absorbent body are fixed together by an adhesive layer over the entire surface or almost the entire surface, a plurality of recesses are formed in the top sheet by repeatedly arranging unit patterns of recesses recessed toward the absorbent body in the longitudinal and lateral directions of the top sheet, the recesses protrude beyond the thickness of the top sheet toward the absorbent body and do not reach the absorbent body; A body fluid absorbent article in which the open area ratio of the recesses in the top sheet is 4% or more and 10% or less.

2. The body fluid absorbent article according to claim 1, wherein a plurality of unit rows each formed by repeating unit patterns of recesses in a direction inclined relative to the longitudinal or lateral direction of the top sheet are arranged parallel to one another.

3. The body fluid absorbent article according to claim 1 or 2, wherein the top sheet has a longitudinally elongated shape in which the longitudinal length is longer than the lateral length, and the unit patterns of the recesses are repeatedly arranged in a direction inclined with respect to the lateral direction.

4. 4. The body fluid absorbent article according to claim 1, wherein the top sheet has a vertically elongated shape in which the length in the vertical direction is longer than the length in the horizontal direction, and the unit patterns of the recesses are repeatedly arranged in a direction inclined with respect to the vertical direction.

5. 5. The body fluid absorbent article according to claim 1, wherein the top sheet has a plurality of dense regions in which a plurality of the recesses are gathered, and each of the dense regions is surrounded by a sparse region in which no recesses are formed.

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