JP6436960B2 - Absorbent articles - Google Patents

Description

  The present invention relates to absorbent articles such as sanitary napkins, panty liners, incontinence pads, and the like, and more particularly to absorbent articles in which a polymer sheet is interposed between a liquid-permeable top sheet and a back sheet.

  Conventionally, as the absorbent article, a body fluid is absorbed and retained between a liquid-impermeable back sheet such as a polyethylene sheet or a polyethylene sheet-laminated nonwoven fabric and a liquid-permeable surface sheet such as a nonwoven fabric or a liquid-permeable plastic sheet. The thing which interposed the absorber provided with the function to perform is known.

  Many improvements have been made to this type of absorbent article, and as the absorbent body, only a superabsorbent polymer (SAP) is disposed between at least two layers of sheets, and each sheet is composed of piled pulp or the like. There has been proposed a polymer sheet (also referred to as an SAP sheet or a Palpress absorber) in which a fibrous absorbent material is not interposed. By using the polymer sheet as an absorbent body, the absorbent article is excellent in that it can absorb and retain a large amount of body fluid while reducing the thickness of the absorbent article.

  However, since the fibrous absorbent material such as piled pulp is not blended in the polymer sheet, the force for drawing body fluid into the absorbent body due to capillary action or the like is weaker than that of the absorbent body using the fibrous absorbent material. There was a problem that the absorption rate was slow. In particular, in the case of menstrual blood having a high viscosity, since it is difficult to be drawn into the absorbent body, anxiety about leakage is increased by diffusing extensively on the surface. If the diffusion area on the surface increases, there is a risk that it may be judged that the absorption performance is low even though no leakage has actually occurred, and there is a risk that subsequent use will be avoided. is there.

  As a technique for coping with such a problem, there are, for example, the following Patent Document 1 in which the diffusibility of the liquid on the surface is suppressed, and the following Patent Document 2 in which an opening is provided in the surface material.

  In the following Patent Document 1, the bottom of the recess has a linear pressure-bonded portion in which constituent fibers are pressure-bonded or bonded, and has a plurality of convex portions surrounded by the recess, Since the intersections of the constituent fibers are joined by means other than pressure bonding in a part other than the part, it is disclosed that the liquid flow and the liquid spread are suppressed by the unevenness and the linear embossed part with large undulations. Yes.

Moreover, in the following Patent Document 2, the excretory fluid is permeated and has a surface sheet facing the skin made of a perforated sheet; An absorbent element containing cotton-like pulp in order to hold, in the perforation group of excretion liquid formed in the excretion region including at least the part of the perforated surface sheet facing the excretion part of the excretion liquid and its periphery, An absorbent article having an effective opening area of a single transmission hole of 3 to 75 mm ² and an opening area ratio of 10 to 80% is disclosed.

JP 2011-137262 A JP 2007-97643 A

  However, in the surface material described in Patent Document 1, since the volume of the linear recess serving as a body fluid temporary storage region is small, the body fluid flowing into the linear recess may overflow and diffuse on the surface. . Moreover, since the linear recessed part continuous in the skin side surface of a surface material is formed, there exists a possibility that the bodily fluid which entered this recessed part may spread | diffuse extensively along a recessed part.

  On the other hand, in the absorbent article described in Patent Document 2, since the top sheet is made of a perforated sheet, body fluid can easily pass through the opening to the absorber side, but menstrual blood or the like absorbed by the absorber from the opening is present. Since it was visible, it had the disadvantages that it was poor in concealment, easily returned from the opening, and increased anxiety about leakage.

  Therefore, a main problem of the present invention is to make it easier to draw body fluid and reduce anxiety about leakage while suppressing diffusion of the liquid on the surface.

In order to solve the above problems, as the present invention according to claim 1, there is provided a polymer sheet in which only a superabsorbent polymer is disposed between at least two layers between a liquid-permeable top sheet and a back sheet. In the interposed absorbent article,
The liquid-permeable surface sheet is a non-porous nonwoven fabric, and is a ridge-like convex portion that is recessed on the non-skin side and is continuous to the periphery in a region including the body fluid discharge site on the skin side surface of the liquid-permeable surface sheet. large number of recesses surrounded by formed of a continuous lattice pattern,
The concave portion is a recess formed with a depth within the range of the thickness of the liquid-permeable surface sheet, and the skin side surface of the liquid-permeable surface sheet is formed in an uneven shape by the concave portion and the convex portion. The non-skin side of the sheet is formed flat,
Area per one of the recess together are 30 -1000 mM ^2, the width of the convex portion is a 0.5 to 10 mm, the area of the recess 1.5 of the area of the convex portion An absorbent article characterized by being 20 times is provided.

In the first aspect of the present invention, a sheet-like polymer sheet in which only the superabsorbent polymer is disposed between at least two layers of sheets and no fibrous absorbent material made of piled pulp or the like is interposed between the sheets is used. in the absorbent article had, a skin side of the liquid-pervious topsheet in a region including a body fluid drainage site, together with the recessed non-skin side, the large number of recesses surrounded by the ridge-like protrusions surrounding continuous Since it is formed in a continuous lattice pattern, the discharged body fluid is temporarily stored in the recess, and then penetrates into the absorber on the lower layer side. In the recess, since the surface of the surface sheet is more compact than the conventional one in which such a recess is not provided, the permeation rate of the body fluid into the sheet is slightly reduced, and the body fluid that has entered the recess is temporarily Therefore, the penetration rate of body fluid into the lower polymer sheet is moderately suppressed, and the absorption rate of the superabsorbent polymer, which is slower than the pulp, is absorbed from the liquid-permeable surface sheet. The balance with the permeating speed becomes good, and the body fluid diffused through the polymer sheet is surely absorbed and retained by the superabsorbent polymer without causing overflow in the polymer sheet.

  On the surface of the liquid-permeable surface sheet, the discharged body fluid is temporarily stored in a recess surrounded by a bowl-shaped projection that is continuous with the periphery, so that the diffusion of the liquid on the surface is minimized. When the wearer confirms the diffusion state of the liquid after use, the anxiety about leakage can be reduced.

  Furthermore, since the liquid-permeable surface sheet is appropriately consolidated in the concave portion, the body fluid easily moves from the low density region to the high density region due to the density difference, and a body fluid drawing action occurs.

In the present invention, the recess is a recess formed with a depth within the range of the thickness of the liquid-permeable surface sheet, and the skin side surface of the liquid-permeable surface sheet is formed in an uneven shape by the recess and the projection, The non-skin side surface of the liquid-permeable surface sheet is formed flat.

The area per recess is 30 to 1000 mm ² , the width of the protrusion is 0.5 to 10 mm, and the area of the recess is 1. 5 to 20 times .

  As the present invention according to claim 2, there is provided the absorbent article according to claim 1, wherein the bottom surface of the recess is formed in a cross-sectional shape in which the depth gradually increases toward the center of the recess.

  In the invention of claim 2, the fiber density of the liquid-permeable surface sheet is increased from the peripheral portion to the center by forming the bottom surface of the concave portion in a cross-sectional shape in which the depth gradually increases toward the central portion of the concave portion. Since it changes so as to gradually increase toward the part, body fluid can easily permeate due to the difference in fiber density, and it is difficult for liquid residue to occur between the fibers, so that the remaining body fluid can be prevented from returning to the surface. become.

As the present invention according to claim 3 , there is provided the absorbent article according to any one of claims 1 and 2 , wherein the concave portion is welded to the non-skin side surface of the liquid-permeable surface sheet at the deepest portion of the central portion. The

In the invention of claim 3 , in the recess, the fiber density distribution of the liquid-permeable surface sheet is the deepest portion of the central portion by welding to the non-skin side surface of the liquid-permeable surface sheet at the deepest portion of the central portion. Since the body fluid becomes the highest density and the body fluid is easily drawn into this portion due to the difference in fiber density, the body fluid penetrates into the absorbent body through the central portion of the recess.

As the present invention according to claim 4 , there is provided the absorbent article according to any one of claims 1 to 3 , wherein a planar shape of the recess is a polygon, a circle or an ellipse.

In the invention described in claim 4 , as a preferable planar shape of the concave portion, a rhombus, a hexagon, a polygon such as a triangle, a circle or an ellipse are cited. Thereby, while the external appearance of a liquid-permeable surface sheet becomes favorable, a bodily fluid becomes easy to flow into a recessed part.

As the present invention according to claim 5 , the absorbent article according to any one of claims 1 to 4 , wherein the liquid-permeable surface sheet is composed of a single-layer sheet or a multilayer structure in which a plurality of sheets are laminated. Is done.

In the invention according to the fifth aspect , the liquid-permeable surface sheet may be a single-layer sheet or a multilayer structure in which a plurality of sheets are laminated. . In order to increase the pulling power of the liquid, it is more preferable to have a multilayer structure in which the fiber density and the fiber thickness of the skin side layer and the non-skin side layer can be changed.

  As described above in detail, according to the present invention, diffusion of liquid on the surface is suppressed, body fluid is easily drawn in, and anxiety about leakage can be reduced.

It is a partial fracture development view of sanitary napkin 1 concerning the present invention. It is the II-II arrow directional view of FIG. 3 is an enlarged plan view of a skin side surface of a liquid-permeable surface sheet 3. FIG. It is sectional drawing (the AA arrow directional view and BB arrow directional view of FIG. 3) of the liquid-permeable surface sheet 3. FIG. (A) is a liquid absorption state using a conventional pulp-containing absorber, (B) is a liquid absorption state using a conventional liquid-permeable surface sheet, (C) is a cross-sectional view showing the liquid absorption state of the present invention. is there. It is sectional drawing of the liquid-permeable surface sheet 3 which concerns on a modification. It is an enlarged plan view of the skin side surface of the liquid-permeable surface sheet 3 which concerns on a modification. 3 is a cross-sectional view of a liquid-permeable top sheet 3. FIG. It is sectional drawing of the polymer sheet 4 which concerns on a modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Basic structure of sanitary napkin 1]
As shown in FIGS. 1 and 2, the sanitary napkin 1 according to the present invention has a liquid-impervious back sheet 2 made of a polyethylene sheet, a polypropylene sheet, or the like, and a permeate that quickly permeates menstrual blood or a cage. A liquid surface sheet 3, a polymer sheet 4 in which a superabsorbent polymer is disposed between two sheets interposed between both sheets 2 and 3, and a longitudinal direction on each side of the surface. The side nonwoven fabrics 7 and 7 are formed. Further, in the periphery of the polymer sheet 4, the outer edge portions of the liquid-impermeable back sheet 2 and the liquid-permeable surface sheet 3 are hot-melt adhesive, heat seal, etc. The liquid-impermeable back sheet 2 and the side nonwoven fabric 7 that are joined by the adhesive means and extend laterally from the side edges of the polymer sheet 4 at both side edges thereof are adhesives such as hot melt, Joined by adhesive means such as heat sealing, an outer peripheral flap portion where the polymer sheet 4 does not exist is formed on the outer periphery.

Hereinafter, the structure of the sanitary napkin 1 will be described in detail.
As the liquid-impermeable back sheet 2, a sheet material having at least water shielding properties such as an olefin resin sheet such as polyethylene or polypropylene is used. In addition, a laminated nonwoven fabric obtained by laminating a nonwoven fabric on a polyethylene sheet or the like, or A nonwoven fabric sheet (in this case, the waterproof film and the nonwoven fabric constitute a liquid-impervious back sheet) can be used after substantially impervious to liquid imperviousness by interposing a waterproof film. In recent years, those having moisture permeability tend to be used from the viewpoint of preventing stuffiness. This water- and moisture-permeable sheet material is a microporous sheet obtained by forming a sheet by melting and kneading an inorganic filler in an olefin resin such as polyethylene or polypropylene, and then stretching in a uniaxial or biaxial direction. It is.

  The polymer sheet 4 interposed between the liquid-impermeable back sheet 2 and the liquid-permeable surface sheet 3 is disposed at least on the skin side (liquid-permeable surface sheet 3 side) as shown in FIG. In addition, the superabsorbent polymer 4C is arranged between the upper layer sheet 4A and the lower layer sheet 4B arranged on the non-skin side (impermeable liquid back sheet 2 side). Compared to a thin sheet, it is formed. In the illustrated example, the polymer sheet 4 has a two-layer structure in which a superabsorbent polymer 4C is disposed between the upper layer sheet 4A and the lower layer sheet 4B, but as shown in FIG. 9, between these sheets 4A and 4B. One or a plurality of intermediate sheets 4D in the illustrated example are arranged between the sheets (between the upper sheet 4A and the intermediate sheet 4D, between the intermediate sheets 4D, between the intermediate sheet 4D and the lower sheet 4B). It may be formed in a five-layer structure or more in which the superabsorbent polymer 4C is disposed in the middle). Between the sheets, a fibrous absorbent material made of piled pulp or the like is not interposed, and only the powdery superabsorbent polymer 4C is disposed. For this reason, the thickness of the polymer sheet 4 can be reduced, and the sanitary napkin 1 can be reliably reduced in thickness.

  As the upper layer sheet 4A constituting the polymer sheet 4, a perforated or non-porous nonwoven fabric, a crepe paper, a pulp sheet or a porous plastic sheet is used. As the raw material fibers constituting the nonwoven fabric, in the same manner as the liquid-permeable surface sheet 3, for example, synthetic fibers such as olefins such as polyethylene or polypropylene, polyesters, and polyamides, recycled fibers such as rayon and cupra, cotton Natural fibers such as Although the processing method of the said nonwoven fabric is not ask | required, in order to prevent dropping of the superabsorbent polymer 4C, it is preferable to set it as the processing method which increases the fiber density of the product obtained, such as the spun bond method, the melt blown method, and the needle punch method. . The pore diameter of the porous plastic sheet is preferably smaller than the average outer shape of the superabsorbent polymer 4C in order to prevent the superabsorbent polymer 4C from falling off.

  Further, as the lower layer sheet 4B, a sheet material having water shielding properties can be used in addition to a perforated or non-porous nonwoven fabric, a crepe paper, a pulp sheet, or a porous plastic sheet. As with the upper layer sheet 4A, the nonwoven fabric processing method is not limited. However, in order to prevent the superabsorbent polymer 4C from falling off, the fiber density of the obtained product, such as the spunbond method, the melt blown method, and the needle punch method, is increased. A processing method is preferred. The pore diameter of the porous plastic sheet is preferably smaller than the average outer shape of the superabsorbent polymer 4C in order to prevent the superabsorbent polymer 4C from falling off. As the water-impervious sheet material, the same material as the liquid-impermeable back sheet 2 can be used.

  When the intermediate sheet 4D is provided between the upper layer sheet 4A and the lower layer sheet 4B, the intermediate sheet 4D can be arbitrarily selected from the materials described in the upper layer sheet 4A.

  Examples of the superabsorbent polymer 4C include, for example, a polyacrylate cross-linked product, a self-crosslinked polyacrylate, a saponified acrylate-vinyl acetate copolymer cross-linked product, and a cross-linked isobutylene / maleic anhydride copolymer. , A crosslinked polysulfonate, and a partially crosslinked water-swellable polymer such as polyethylene oxide and polyacrylamide. Among these, those based on acrylic acid or acrylate that are excellent in water absorption and water absorption speed are preferred. In the production process of the highly water-absorbing polymer having the water-absorbing performance, the water-absorbing force and the water-absorbing speed can be adjusted by adjusting the crosslinking density and the crosslinking density gradient.

  On the other hand, side nonwoven fabrics 7 and 7 are provided on both sides of the surface side (skin side) of the sanitary napkin 1 along the longitudinal direction and over almost the entire length of the napkin 1, respectively. Are extended sideways, and wing-shaped flaps W and W are formed by a part of the liquid-impermeable back sheet 2 that is also extended sideways.

  As the side nonwoven fabric 7, a water-repellent treated nonwoven fabric or a hydrophilic treated nonwoven fabric can be used from the viewpoint of an important function. For example, if importance is placed on functions such as preventing permeation of menstrual blood or vaginal discharge, or enhancing the touch feeling, water repellent treatment coated with silicon, paraffin or alkylchromic chloride water repellent It is desirable to use a nonwoven fabric. Further, if importance is attached to the absorption of menstrual blood and the like in the wing-shaped flaps W, W, a method of polymerizing a compound having a hydrophilic group, for example, an oxidation product of polyethylene glycol, in the process of producing a synthetic fiber, , By treating with a metal salt such as stannic chloride, partially dissolving the surface to make it porous, and depositing metal hydroxides to swell or make the synthetic fiber porous, applying capillary action to make it hydrophilic It is desirable to use a hydrophilic treated non-woven fabric provided with.

  As shown in FIG. 2, the inner side of the side nonwoven fabric 7 folds the side nonwoven fabric 7 almost double, and inside the double sheet, in the middle in the height direction, as appropriate at both ends or in the longitudinal direction. One or a plurality of, in the illustrated example, two thread-like elastic elastic members 8 and 8 are disposed, and the double sheet portion is raised on the skin side by the contraction force. , BS is formed.

[Liquid-permeable surface sheet 3]
The liquid-permeable surface sheet 3 is a non-porous nonwoven fabric. Examples of the material fibers constituting the nonwoven fabric include synthetic fibers such as polyethylene or polypropylene, synthetic fibers such as polyester and polyamide, recycled fibers such as rayon and cupra, and natural fibers such as cotton. A nonwoven fabric obtained by an appropriate processing method such as a lace method, a spun bond method, a thermal bond method, a melt blown method, or a needle punch method can be used. Among these processing methods, the spunlace method is excellent in terms of flexibility and the spunbond method is excellent in drapeability, and the thermal bond method and the air-through method are excellent in terms of being bulky and having high compression recovery properties. The non-woven fiber may be either a long fiber or a short fiber, but preferably a short fiber is used in order to give a towel texture. In order to facilitate the embossing treatment, it is preferable to use an olefin fiber such as polyethylene or polypropylene having a relatively low melting point. In addition, a composite fiber such as a core-sheath fiber, a side-by-side fiber, or a split fiber having a fiber having a high melting point as a core and a fiber having a low melting point as a sheath can be suitably used.

  A large number of recesses 10 that are recessed on the non-skin side and surrounded by the ridge-like protrusions 11 that are continuous to the non-skin side in the region of the skin surface of the liquid-permeable surface sheet 3 and including the body fluid discharge site H of the wearer. Are formed in a continuous lattice pattern. That is, on the skin side surface of the liquid-permeable surface sheet 3, by embossing from the skin side, a large number of recesses 10, 10... Recessed on the non-skin side are formed in a continuous lattice pattern. By forming the recesses 10, portions other than the recesses 10, 10... Are formed as convex portions 11 relatively projecting toward the skin so as to surround the periphery of the recess 10 in a continuous bowl shape. It has a structure.

  As shown in detail in FIGS. 3 and 4, the concave portion 10 is squeezed at a depth within the thickness range of the liquid-permeable surface sheet 3 by embossing from the skin side surface of the liquid-permeable surface sheet 3. It is the hollow part formed by doing. Therefore, the skin side surface of the liquid-permeable surface sheet 3 is formed in a concavo-convex shape by the concave portions 10, 10. On the other hand, the non-skin side surface of the liquid-permeable surface sheet 3 is formed substantially flat.

  The convex portion 11 is a portion that protrudes relatively to the skin side from the concave portion 10, and when the concave portion 10 is formed by embossing, the convex portion 11 is a non-pressed portion that is not squeezed at all, or the compressive strength is weaker than the concave portion 10. It consists of a low pressing part. The convex portion 11 continuously surrounds the periphery of the concave portion 10 and is formed in a bowl shape that forms a partition with the adjacent concave portion 10.

  The lattice pattern by these recessed part 10 and the convex part 11 is formed in the area | region containing a wearer's bodily fluid discharge | emission site | part H. FIG. In the example shown in FIG. 1, the lattice pattern is formed on the entire surface of the liquid-permeable surface sheet 3, but only the intermediate region of the liquid-permeable surface sheet 3 including the body fluid discharge site H of the wearer may be used.

  With the above configuration, in the sanitary napkin 1, the body fluid discharged to the surface of the liquid-permeable surface sheet 3 is temporarily stored in the concave portions 10,. 4 is securely absorbed and retained. The permeation form of the body fluid will be described in comparison with a conventional absorbent article. As shown in FIG. 5 (A), the liquid-permeable surface sheet is made of a non-woven fabric that does not form the recess 10 as in the present invention. In a conventional absorbent article using a fibrous absorbent material in which a superabsorbent polymer is blended in a piled pulp as an absorbent material, the body fluid discharged on the surface of the liquid-permeable surface sheet is Quickly penetrates into the absorbent body through the fibers of the porous surface sheet and through a large number of apertures, and is absorbed by the pulp with a relatively high absorption rate and then absorbed and retained by the superabsorbent polymer with a relatively low absorption rate. It takes the form of absorption. A conventional absorbent article using such a fibrous absorbent body is excellent in absorption speed and utilizes the difference in absorption speed between pulp and polymer to ensure that the body fluid is held in the absorbent body. However, in such an absorbent article, since bulky piled pulp is used for the absorbent body, the thickness of the absorbent body has to be increased, and it has been difficult to reduce the thickness.

  Next, in order to reduce the thickness of the absorbent article, instead of the fibrous absorbent body of FIG. 5 (A), as shown in FIG. When the polymer sheet provided with is used, the body fluid discharged to the surface of the liquid-permeable surface sheet quickly passes through the liquid-permeable surface sheet and moves to the polymer sheet. However, in the polymer sheet, since the water-absorbing material is composed only of the polymer, a large amount of body fluid that has permeated the liquid-permeable surface sheet flows into the polymer sheet even though the water absorption rate of the polymer is low. Therefore, the body fluid that has flowed into the polymer sheet overflows and returns to the surface side, and the body fluid discharged without being transferred to the polymer sheet flows on the surface as it is, so that the diffusion area on the surface tends to increase. is there. Therefore, if the wearer who confirmed the surface of the used absorbent article has a large diffusion area of the body fluid on the surface, it may be an absorbent article with low absorption performance even if leakage does not actually occur. May cause doubts.

  On the other hand, in the sanitary napkin 1, as shown in FIG. 5C, when the body fluid discharged to the surface of the liquid-permeable surface sheet 3 flows into the recess 10, the surface of the recess 10 Therefore, the body fluid permeation rate into the inside of the top sheet is slightly reduced as compared with the conventional one in which such a recess 10 is not provided. It will be in the state temporarily stored in. For this reason, the penetration rate of the body fluid into the lower polymer sheet 4 is moderately suppressed, and the rate of absorption by the superabsorbent polymer having a lower absorption rate than that of the pulp and the penetration from the liquid-permeable surface sheet 3. The balance with the speed becomes good, and the body fluid that has diffused inside the polymer sheet 4 is surely absorbed and retained by the superabsorbent polymer sequentially in the process of diffusing in the surface direction without causing overflow of the body fluid in the polymer sheet 4. It becomes like this.

  On the surface of the liquid-permeable surface sheet 3, the discharged body fluid is temporarily stored in the concave portion 10 surrounded by the bowl-shaped convex portion 11, and the diffusion of the liquid on the surface is minimized. When the wearer confirms the diffusion state of the liquid after use, the feeling of anxiety about leakage can be reduced.

  Further, as shown in FIG. 4, in the concave portion 10, since the liquid-permeable topsheet 3 is consolidated, the body fluid tends to move from the low density region to the high density region due to the density difference. Even with high menstrual blood and the like, it tends to cause a body fluid drawing action.

  In plan view of the liquid-permeable surface sheet 3, the area of the concave portion 10 is 1.5 to 20 times, preferably 3 to 10 times the area of the convex portion 11. If this area ratio is smaller than 1.5 times, the area of the recess 10 is too small and the effect of storing body fluid is reduced. On the contrary, if it is larger than 20 times, the convex portion 11 is too small and the section between the adjacent concave portions 10 and 10 is likely to be damaged, and the temporarily stored body fluid may flow into the adjacent concave portion 10. The area ratio between the concave portion 10 and the convex portion 11 can be calculated from the ratio of the total area of the entire range in which the concave portion 10 and the convex portion 11 are formed.

  As shown in FIG. 4, the bottom surface of the recess 10 is preferably formed in a cross-sectional shape that gradually becomes deeper toward the center of the recess 10. As a result, the fiber density of the liquid-permeable surface sheet 3 on the lower side of the recess 10 is formed so as to gradually increase from the peripheral part to the central part, and the body fluid is directed from the peripheral part to the central part due to the difference in fiber density. And the liquid does not easily remain between the fibers, and the body fluid does not return to the surface.

  As shown in FIG. 4, the bottom surface of the recess 10 is preferably formed in an arc shape that bulges to the non-skin side as seen in a cross-sectional view of the liquid-permeable surface sheet 3. Thereby, the change in the fiber density from the outer peripheral part of the concave part toward the central part of the concave part in the lower liquid-permeable surface sheet 3 gradually increases toward the central part, which is optimal for drawing in body fluid due to the difference in fiber density. It becomes a state. Moreover, you may form the bottom face of the said recessed part 10 in the linear form which bulges to the non-skin side linearly toward a center part, as FIG. 6 shows.

  The concave portion 10 preferably forms a welded portion 12 welded to the non-skin side surface of the liquid-permeable surface sheet 3 at the deepest portion of the central portion. Thereby, the body fluid is easily drawn into the welded portion 12 due to the difference in fiber density, and the body fluid penetrates into the polymer sheet 4 through the welded portion 12. As a means of welding, it can carry out by heating at the time of embossing or by ultrasonic waves. The area of the welded portion 12 is preferably 1 to 10% of the area per recess 10. When it exceeds 10%, since the liquid permeability in the welding part 12 is low, there exists a possibility that the osmosis | permeation rate of a bodily fluid may fall. In the example shown in FIG. 4, the surface of the weld portion 12 is formed in a continuous curved line shape from the surrounding shape, but may be formed flat.

The area per one recess 10 is 30 to 1000 mm ² , preferably 30 to 300, and more preferably 30 to 150 mm ² . For example, when the area per recess 10 is 30 mm ² and the depth is 2.5 mm, the volume of the recess 10 can be about 20 mm ^3, and about 50 recesses are required to store 1 cc of menstrual blood. 10, 10... Are required, and simply multiplying the area of the concave portion 10 results in a diffusion area of about 1500 mm ² (in fact, there is a convex portion 11 between the adjacent concave portions 10, 10. The diffusion area becomes larger by that amount). The diffusion area of 1500 mm ² in the liquid-permeable surface sheet 3 is close to the size of the boundary as to whether or not an anxiety about leakage occurs when the wearer confirms the used sanitary napkin 1. When the diffusion area is large, anxiety about leakage increases significantly. Therefore, the area per one recess 10 is preferably 30 mm ² . When the area of the concave portion 10 exceeds 1000 mm ² , the concave portion 10 is too large, and when the sanitary napkin 1 is curved along the roundness of the body, the shape of the concave portion 10 is likely to change, and the effect of storing body fluid is reduced. There is a risk.

  The said recessed part 10 ... is arrange | positioned by the continuous lattice pattern by planar view from the skin side of the liquid-permeable surface sheet 3. FIG. The continuous lattice pattern includes a regular lattice pattern in which a large number of the recesses 10, 10... Are arranged in the longitudinal direction or the width direction of the sanitary napkin 1, and a rhombus pattern in which a large number of the recesses 10, 10. Is included. The concave portions 10 are arranged at a predetermined interval, and the convex portions 11 are provided between the adjacent concave portions 10 and 10.

  In the example shown in FIG. 3, the concave portion 10 is formed in a substantially diamond shape in plan view, and a large number of concave portions 10, 10. This pattern is desirable because the appearance of the lattice pattern is good and the body fluid can easily flow into the concave portion 10 and the liquid diffusion on the surface can be suppressed to a low level. The rhombus shape of the recess 10 is formed long in the longitudinal direction of the sanitary napkin 1, but may be formed long in the width direction, or may be formed in substantially the same length in the longitudinal direction and the width direction. Further, the concave portion 10 is formed in an arbitrary polygonal shape such as a hexagon shown in FIG. 7A or a triangle shown in FIG. 7B, and continuously in a regular lattice pattern or a rhombus pattern. Many can be arranged. Further, it may be a circle shown in FIG. 7C or an ellipse shown in FIG. 7D.

  The convex portions 11 may be formed with substantially equal widths (see FIGS. 3 and 7A and 7B), or may be formed with different widths (FIGS. 7C and 7D). reference). The width of the convex portion 11 is preferably about 0.5 to 10 mm, particularly about 0.5 to 3 mm. As a result, the adjacent concave portions 10 and 10 can be clearly defined, and the amount of body fluid stored in the concave portion 10 can be prevented from being reduced due to the interval between the concave portions 10 and 10 being too wide.

  In order to form the concavo-convex pattern on the liquid-permeable surface sheet 3, the embossing roll having a large number of embossing convex portions corresponding to the concave portions 10 on the surface and a flat roll having a flat surface. This can be achieved by passing a non-woven sheet.

  By the way, the liquid-permeable surface sheet 3 may have a single-layer structure composed of a single-layer sheet as shown in FIG. 8 (A), or a plurality of sheets as shown in FIG. 8 (B). A laminated multilayer structure may be used. However, in order to secure a body fluid storage space in the recess 10, it is preferable to use a non-compressed state (state of the nonwoven fabric sheet before forming the recess 10) having a thickness of 1.5 mm or more ( Total thickness in case of multi-layer structure).

  When the liquid-permeable surface sheet 3 has a multilayer structure, it is possible to add various performances by using sheets having different configurations in each layer. For example, by using a fiber having a higher fiber density on the non-skin side or a fiber having a smaller fiber thickness than the skin side, by providing a fiber density change from the skin side to the non-skin side in advance, to the non-skin side The body fluid drawing force can be increased.

As the optimum configuration example enhanced pulling force of the fibers consists air-through nonwoven fabric skin side layer are mixed fibers of thickness 3.0 dtex / 2.0 dtex, each basis weight ^{6g / m 2 / 12g / m} 2, the non The skin side layer may have a two-layer structure made of an air-through nonwoven fabric having a fiber thickness of 1.8 dtex and a basis weight of 18 g / m ² .

  When the liquid-permeable surface sheet 3 has a multilayer structure, the non-skin side layer has a core-sheath type bicomponent non-woven fabric or side-by-side fiber in which a fiber having a high melting point is a core and a fiber having a low melting point is a sheath. A nonwoven fabric made of a composite fiber such as a split fiber can be used. Thereby, since the non-skin side layer can be densified with fine fibers, the pulling force of the liquid can be increased.

  Moreover, when the said liquid-permeable surface sheet 3 is made into a multilayered structure, it is preferable to use a non-opening (non-porous) nonwoven fabric for the layer which comprises a skin contact surface layer at least. The non-perforated hole does not mean that there is essentially no space formed between the fibers of the nonwoven fabric, but an opening formed mechanically by post-processing such as pin piercing after forming the nonwoven fabric sheet. It does not have a hole, that is, an opening provided linearly from the skin side surface to the non-skin side surface of the nonwoven fabric sheet. The layer on the non-skin side from the skin contact surface layer may be a perforated sheet subjected to a perforation process.

  DESCRIPTION OF SYMBOLS 1 ... Sanitary napkin, 2 ... Liquid-impermeable back sheet, 3 ... Liquid-permeable surface sheet, 4 ... Polymer sheet, 7 ... Side nonwoven fabric, 8 ... Filament elastic elastic member, 4A ... Upper layer sheet, 4B ... Lower layer sheet, 4C: superabsorbent polymer, 10 ... concave, 11 ... convex, 12 ... weld

Claims (5)

In an absorbent article in which a polymer sheet in which only a superabsorbent polymer is disposed between at least two layers of sheets is interposed between a liquid-permeable surface sheet and a back sheet,
The liquid-permeable surface sheet is a non-porous nonwoven fabric, and is a ridge-like convex portion that is recessed on the non-skin side and is continuous to the periphery in a region including the body fluid discharge site on the skin side surface of the liquid-permeable surface sheet. large number of recesses surrounded by formed of a continuous lattice pattern,
The concave portion is a recess formed with a depth within the range of the thickness of the liquid-permeable surface sheet, and the skin side surface of the liquid-permeable surface sheet is formed in an uneven shape by the concave portion and the convex portion. The non-skin side of the sheet is formed flat,
Area per one of the recess together are 30 -1000 mM ^2, the width of the convex portion is a 0.5 to 10 mm, the area of the recess 1.5 of the area of the convex portion Absorbent article characterized by being 20 times .   The absorbent article according to claim 1, wherein the bottom surface of the recess is formed in a cross-sectional shape in which the depth gradually increases toward the center of the recess.   The absorbent article according to claim 1, wherein the concave portion is welded to a non-skin side surface of the liquid-permeable surface sheet at a deepest portion of a central portion. The absorptive article according to any one of claims 1 to 3 whose plane shape of said crevice is a polygon, a circle, or an ellipse. The absorbent article according to any one of claims 1 to 4, wherein the liquid-permeable surface sheet is composed of a single-layer sheet or a multilayer structure in which a plurality of sheets are laminated.

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