JP6599116B2 - Absorbent articles - Google Patents

Description

  The present invention relates to absorbent articles such as sanitary napkins, panty liners, and incontinence pads for absorbing menstrual blood and vaginal discharge. Specifically, the opening of the liquid-permeable surface sheet and the embossment of the absorbent body are predetermined. It is related with the absorbent article arrange | positioned so that it may overlap in the ratio.

  Conventionally, as an absorbent article such as a panty liner, sanitary napkin, incontinence pad, a liquid-impervious 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 There is known an intervening absorber made of cotton-like pulp or the like.

  Many improvements have been made on this type of absorbent article, and various measures have been taken to make it easier for the absorbent to absorb bodily fluids. For example, in the following Patent Document 1, the absorbent body has a plurality of compressed portions formed by squeezing a part of the absorbent body in the thickness direction, and the liquid-permeable top sheet is a nonwoven fabric. There is disclosed an absorbent article having holes that do not exist, and in which the holes of the liquid-permeable top sheet and the compressed parts of the absorbent body are at least partially overlapped in the thickness direction of the absorbent article.

JP 2012-1000094 A

  However, in the absorbent article described in Patent Document 1, when the compressed portion of the absorber and the opening of the top sheet are provided separately, the relative positions of the compressed portion of the absorber and the opening of the top sheet are shifted. By this, it is thought that the product with a low effect which the absorption performance in the overlap part of the pressing part of an absorber and the opening of a top sheet improves is produced in a fixed ratio.

  Therefore, the main problem of the present invention is that a product having an optimum absorption performance can be continuously obtained by providing an overlapping portion of the opening of the liquid-permeable surface sheet and the embossment of the absorber at a predetermined ratio. It is to provide an absorbent article.

In order to solve the above-mentioned problem, as the present invention according to claim 1, a large number of embosses are given by pressing from the skin side between the liquid-permeable top sheet and the back sheet in which a large number of openings are formed. While the absorbent body is interposed, the absorbent article is arranged so that the opening and the embossing overlap at a predetermined rate in the thickness direction,
Wherein both apertures and embossing plane shape is circular, with a diameter _{D 10} of the apertures are 0.5 mm to 3 mm, the pitch _{P 10} of the opening is of a diameter of the aperture _{D 10} 1 It is .5 times to 1.8 times, and the diameter _{D 11} of the embossed is 1.3 times to 2 times the diameter _{D 10} of the apertures, the apertures are arranged in a grid pattern or a staggered pattern, The embosses are arranged in a lattice or zigzag pattern,
Under the pitch P _10, conditions the diameter D ₁₀ diameters D ₁₁ and the opening 10 of the embossing were set in the above range of the aperture, pitch P ₁₁ of the embossments from the following equation (1) by being pitch ratio _{P R} is set to be 0.7 to 0.9,
Pitch ratio P _R = (Pitch P _{10 of the} opening 10) / (Pitch P _{11 of the} emboss ₁₁ ) (1)
In a circle with a diameter of 50 mm centered on the body fluid discharge site of the wearer, obtained from the formula : (total area of overlapping portion where the opening and embossing overlap in the thickness direction) / (total area of the opening) × 100 The absorbent article is characterized in that the overlapping ratio of the opening and the embossing is set to 17% to 73%.

  In the first aspect of the present invention, the pitch ratio and the overlap ratio are respectively defined in a predetermined range so that the openings of the liquid-permeable surface sheet and the embossment of the absorber overlap at a predetermined ratio. .

To the overlap ratio to 17% to 73%, and setting the pitch ratio P _R to 0.7 to 0.9. By setting the overlap ratio to 17% to 73%, the openings of the liquid-permeable surface sheet overlap with the embossment of the absorber at an appropriate ratio, so that the optimum absorption performance can be obtained. That is, in the overlapping portion of the opening and the emboss, the body fluid flows directly into the emboss through the opening, and after being temporarily stored here, follows a path that is absorbed by the absorber from the peripheral surface of the emboss. Further, in the portion other than the overlapping portion, an absorbent body that is not squeezed is interposed in the opening. Follow the path of diffusion through the absorbent body as it is quickly drawn into the surroundings. Since these two routes are appropriately combined to absorb the body fluid, the absorption speed, the amount of reversion, the diffusion area, etc. are improved, and the optimum absorption performance can be obtained.

  In addition, even when the relative position between the liquid-permeable surface sheet and the absorbent body is slightly shifted during the production process, the opening of the liquid-permeable surface sheet and the embossment of the absorbent body are set to the above-described pitch ratio and overlapping rate. As a result, it is possible to continuously obtain a product having a certain absorption performance in which the improvement effect of the absorption performance due to the provision of the overlapping portion of the opening of the liquid-permeable surface sheet and the embossment of the absorber is sufficiently exhibited. become.

  On the other hand, if the overlap ratio is smaller than 17%, it is not preferable from the experimental results described in detail later because the absorption speed becomes slow, the amount of reversion increases, and the diffusion area tends to expand.

  Note that “the pitch of the openings” is the distance between the centers of the adjacent openings, and “the pitch of the embosses” is the distance between the centers of the adjacent embosses.

In the present invention, the aperture diameter D ₁₀ of when the planar shape of the aperture is circular, and the 0.5 mm to 3 mm. It hardly fluid flows into the opening when the diameter D ₁₀ of the aperture is too small, too large absorber not squeezed emboss area that is exposed increases from the opening, return amount is increased fear is there.

In the present invention, since both the opening and the emboss have a circular planar shape, the opening and the emboss are easily overlapped.

In the present invention, the aperture pitch P ₁₀ of when the planar shape of the opening in the circular, is 1.5 times to 1.8 times the hole diameter. While the pitch P ₁₀ of the opening is much the return amount is too small, the percentage of overlap is too large embossed decreases.

In the present invention, the diameter D ₁₁ of the embossed upon the planar shape of the opening in the circular, is 1.3 times to 2 times the diameter D ₁₀ of the aperture. Ratio overlapping with openings when the diameter D ₁₁ of the embossing is too small decreases, the volume of the absorber obtained too large decreases the absorption speed may be reduced.

In the present invention, the apertures and the embosses are arranged in a lattice shape or a zigzag shape, respectively, so that they are likely to overlap each other.

As the present invention according to claim 2, wherein the embossed absorbent article of claim 1 Symbol placement has been granted in a region including at least body fluid discharge portions are provided.

In the invention described in claim 2 , the absorption performance of this region is optimized by applying the embossment of the absorber to the region including at least the body fluid discharge site.

  As described above in detail, according to the present invention, the optimum absorption performance can be obtained by providing the overlapping portion of the opening and the emboss at a predetermined ratio.

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. It is a top view (the 1) which shows the overlapping state of the opening 10 and the embossing 11. FIG. It is a top view (the 2) which shows the overlapping state of the opening 10 and the embossing 11. FIG. 3 is a cross-sectional view showing the flow of body fluid when all of the apertures 10 overlap with the emboss 11. FIG. 3 is a cross-sectional view showing a flow of body fluid when a part of the opening 10 overlaps with the emboss 11; FIG. It is a graph which shows the relationship between an overlap rate and absorption speed. It is a graph which shows the relationship between an overlap rate and a diffusion area. It is a graph which shows the relationship between an overlap rate and a return amount. It is a top view at the time of arrange | positioning in zigzag form.

  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. The liquid surface sheet 3, the absorbent body 4 made of cotton-like pulp or synthetic pulp interposed between the two sheets 2 and 3, and the absorbent body 4 for maintaining the shape of the absorbent body 4 and improving the diffusibility. The wrapping sheet 5 is made of crepe paper or nonwoven fabric that surrounds the wrapping paper, and side nonwoven fabrics 7 and 7 are disposed on both sides of the surface along the longitudinal direction. Further, in the periphery of the absorbent body 4, at the front and rear end edges in the longitudinal direction of the napkin, the outer edge portion of the liquid-impermeable back sheet 2 and the liquid-permeable surface sheet 3 is an adhesive such as hot melt or heat seal. The liquid-impervious back sheet 2 and the side nonwoven fabric 7 which are joined by an adhesive means such as the like and are extended laterally from the edge of the absorbent body 4 at both side edges thereof. The outer periphery flap part which does not have the absorber 4 is formed in the outer periphery by joining by adhesion | attachment means, such as a heat seal.

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.

  Next, the liquid-permeable surface sheet 3 is preferably a non-woven fabric or a porous plastic sheet in which a large number of openings are formed. 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. Of these processing methods, the spunlace method is superior in terms of flexibility and the spunbond method is superior in drapeability, and the thermal bond method is superior in terms of being bulky and having high compression recovery properties. As the material sheet constituting the plastic sheet, for example, an olefin resin such as polyethylene or polypropylene is preferably used, but a polyamide resin such as polyester, nylon, EVA, or the like can also be used. The liquid permeable top sheet 3 will be described in detail later.

  The absorbent body 4 interposed between the liquid-impermeable back sheet 2 and the liquid-permeable surface sheet 3 is, for example, a mixture of a superabsorbent resin in pulp or a mixture of chemical fibers in the pulp. In addition, those mixed with a superabsorbent resin are used. As shown in the figure, it is desirable that the absorbent body 4 is surrounded by the encapsulating sheet 5 in order to maintain the shape and quickly diffuse menstrual blood and prevent reversal of once absorbed menstrual blood and the like. Examples of the pulp include chemical fibers obtained from wood, cellulose fibers such as molten pulp, and those made of artificial cellulose fibers such as rayon and acetate. It is preferably used in terms of price. The absorber 4 will be described in detail later.

  The absorbent body 4 may be mixed with synthetic fibers. As the synthetic fiber, for example, polyolefins such as polyethylene or polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon, and copolymers thereof can be used. It may be a mixture. 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 also be used. In the case of a hydrophobic fiber, it is desirable to use a synthetic fiber that has been surface-treated with a hydrophilizing agent so as to have an affinity for body fluids.

  Examples of the superabsorbent resin include cross-linked polyacrylate, self-crosslinked polyacrylate, saponified acrylate-vinyl acetate copolymer cross-linked, isobutylene / maleic anhydride copolymer cross-linked, Examples include cross-linked polysulfonates, and partially cross-linked water-swellable polymers 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-absorbent resin having the water absorption performance, the water absorption force and the water absorption speed can be adjusted by adjusting the crosslinking density and the crosslinking density gradient. The content of the highly water-absorbent resin is desirably 10 to 60% of the weight of the absorber. When the content of the superabsorbent resin is less than 10%, sufficient absorbability cannot be provided, and when it exceeds 60%, the entanglement between the pulp fibers disappears, the sheet strength decreases, and tears, cracks, etc. Is likely to occur.

  When providing the encapsulating sheet 5 surrounding the absorbent body 4 as in this example, as a result, the encapsulating sheet 5 is interposed between the liquid-permeable surface sheet 3 and the absorbent body 4, A body fluid is quickly diffused by the encapsulating sheet 5 having excellent absorbability, and reversal of menstrual blood and the like is prevented.

  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. 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, The synthetic fiber is swelled or made porous by treating with a metal salt such as stannic chloride, partially dissolving the surface to make it porous, and depositing metal hydroxide, etc. It is desirable to use a hydrophilic treated non-woven fabric provided with.

  Although not shown in the drawing, the inner side of the side nonwoven fabric 7 is folded back and one or more elastic elastic members are arranged at predetermined positions so that the inner side portion of the side nonwoven fabric is brought to the surface side by the contraction force. You may make it form the standing three-dimensional gather.

[About the liquid-permeable surface sheet 3 and the absorber 4]
As shown in FIG. 1, the liquid-permeable surface sheet 3 has a large number of apertures 10, 10... Formed at predetermined intervals in the napkin longitudinal direction and the width direction. The opening 10 may be provided at least in a region including the blood drainage port H of the wearer, but is preferably formed on the entire surface of the liquid-permeable surface sheet 3 as in the illustrated example.

  The planar shape of the opening 10 is preferably circular as shown in FIGS. 3 and 4. Thereby, it becomes easy to overlap with the emboss 11 of the absorber 4 described in detail later. Further, in addition to a circle, it may be formed in a planar shape such as an oval or an ellipse.

  As shown in FIGS. 3 and 4, the array of the apertures 10 is preferably in a lattice shape aligned along the napkin longitudinal direction and the napkin width direction. Alternatively, they may be arranged in a zigzag pattern aligned along a direction inclined at a predetermined angle with respect to the napkin longitudinal direction and the napkin width direction (see FIG. 10).

As shown in FIG. 3, the diameter D10 of the opening 10 is 0.5 mm to 3 mm, preferably ₁ mm to 3 mm, more preferably 1.5 mm to 3 mm. Menstrual blood hardly flow into the diameter D ₁₀ of 0.5mm smaller than aperture 10 of the aperture 10, to menstrual blood becomes difficult to transmit the liquid-permeable topsheet 3, 3 mm larger than the liquid permeable The area of the absorbent body 4 (absorbent body 4 surrounded by the encapsulating sheet 5) disposed in the lower layer of the conductive surface sheet 3 that is not embossed is exposed to an excessively large area and is absorbed by the absorbent body 4. There is a risk that the amount of returned menstrual blood will increase.

As shown in FIG. 3, the pitch P ₁₀ of the apertures 10 is preferably 1.5 to 1.8 times the diameter D ₁₀ of the apertures 10. That is, when the diameter _{D 10} of the opening 10 was set to 0.5 mm to 3 mm, the pitch _{P 10} of the preferred aperture 10 is 0.75Mm～5.4Mm. If the pitch P ₁₀ of the apertures ₁₀ is smaller than 1.5D _10, the density of the apertures 10 formed in the liquid-permeable surface sheet 3 becomes too high, and the amount of reversion may increase. If greater than 8D _10, hardly overlaps with the emboss 11 of the absorbent core 4 to be described later. The pitch P _{10 of the} apertures 10 is the distance between the centers of the apertures 10 and 10 adjacent to each other in the napkin width direction and the napkin longitudinal direction. The pitch in the napkin width direction and the pitch in the napkin longitudinal direction are preferably substantially the same.

  Next, as shown in FIG. 1, the absorbent body 4 is provided with a large number of embosses 11, 11... On the skin side surface (surface on the liquid-permeable surface sheet 3 side) by pressing from the skin side (surface side). Has been. The emboss 11 may be provided at least in a region including the blood drainage port H of the wearer, but is preferably formed on the entire surface of the absorbent body 4 as shown in the drawing. The emboss 11 is formed by squeezing the absorbent body 4. When the absorbent body 4 is surrounded by the encapsulated sheet 5, the encapsulated sheet 5 and the embossed sheet 5 are formed from the outer surface side of the encapsulated sheet 5. You may form by squeezing the absorber 4 integrally.

  The planar shape of the emboss 11 is preferably circular. This makes it easy to overlap with the aperture 10, and the absorbent body 4 is evenly squeezed, and the improvement in capillary action due to the consolidation of the fibers becomes uniform in the circumferential direction, and menstrual blood is easily drawn.

  As shown in FIGS. 3 and 4, the arrangement of the embosses 11 is preferably a lattice shape aligned along the napkin longitudinal direction and the napkin width direction. Alternatively, they may be arranged in a zigzag pattern aligned along a direction inclined at a predetermined angle with respect to the napkin longitudinal direction and the napkin width direction (see FIG. 10).

As shown in FIG. 3, the diameter D _{11 of the} emboss 11 is preferably 1.3 to 2 times the diameter D ₁₀ of the opening 10. That is, when the diameter _{D 10} of the opening 10 was set to 0.5 mm to 3 mm, the diameter _{D 11} of the preferred emboss 11 is 0.65Mm～6mm. Accordingly, the diameter D ₁₀ of the opening 10 is formed smaller than the diameter D _{11 of the} emboss 11, so that it is possible to more reliably prevent the return from the opening 10.

The distance between adjacent embosses 11 and 11 is preferably smaller than the diameter D _{10 of the} opening 10. Thereby, the opening 10 located in the middle between the embosses 11 and 11 is easily overlapped with the emboss 11. However, it is preferable to secure 0.3 mm or more between the embosses 11 and 11 so that the adjacent embosses 11 and 11 do not overlap each other.

In the sanitary napkin 1, the pitch ratio _{P R} obtained from the following equation (1) is set to _{0.7~0.9 (0.7 ≦ P R ≦ 0.9} ).
Pitch ratio P _R = (Pitch P _{10 of} opening 10) / (Pitch P _{11 of} emboss ₁₁ ) (1)
The pitch P _{11 of the} emboss 11 is a center-to-center distance between adjacent embosses 11 and 11.

As apparent from the above equation, pitch _{P 11} of the embossing 11, the pitch ratio _{P R} obtained from the above equation (1) is 0.7 to 0.9 and (0.7 ≦ _{P R} ≦ 0.9) It is set to be. The pitch P ₁₁ of the embossing 11, is that the distance between the centers of the embossing 11, 11 adjacent to each other in napkin width and the napkin longitudinally. The pitch in the napkin width direction and the pitch in the napkin longitudinal direction are preferably substantially the same.

  In the sanitary napkin 1, the opening 10 of the liquid-permeable surface sheet 3 and the emboss 11 of the absorbent body 4 are arranged so as to overlap with each other in the thickness direction of the sanitary napkin 1. That is, as shown in FIGS. 3 and 4, the overlapping portion 12 where the opening 10 and the emboss 11 overlap is provided in a predetermined ratio with respect to the total area of the opening 10 in plan view.

The overlapping ratio M obtained from the following equation (2) is set to 17% to 73% (17% ≦ M ≦ 73%).
Overlap ratio M = (total area of the overlap portion 12 where the opening 10 and the emboss 11 overlap in the thickness direction within a circle with a diameter of 50 mm centered on the wearer's blood drainage port H) / (wearer's blood drainage) The total area of the opening 10 in a circle with a diameter of 50 mm centered on the mouth H) × 100% (2)

  The total area of the overlapping portions 12 is the sum of the areas of a large number of scattered overlapping portions 12, 12. The range in which the overlap ratio M is set is within a circle having a diameter of 50 mm centered on the blood drainage port H of the wearer, at least in the region corresponding to the blood drainage port H of the wearer. This is because 10 and the emboss 11 overlap each other at a predetermined ratio to obtain a predetermined absorption performance.

In order to set the overlap ratio M to 17% to 73%, the pitch P _{10 of the} apertures 10, the diameter D _{11 of the} emboss 11, and the diameter D _{10 of the} aperture 10 are set in the above ranges, respectively. under, the pitch ratio _{P R} can be set by 0.7 to 0.9. That is, by forming the sizes and pitches of the apertures 10 and the embosses 11 in the above ranges, the liquid-permeable surface sheet 3 is disposed at an arbitrary position on the upper surface of the absorbent body 4, and the above ranges are satisfied. An overlap rate M is ensured.

  By setting the overlap ratio M to 17% to 73%, a product in which the apertures 10 of the liquid-permeable surface sheet 3 overlap with the emboss 11 of the absorbent body 4 at an appropriate ratio is continuously obtained. As is clear from the experimental results, the absorption speed of the bodily fluid is increased, the amount of reversion can be reduced, the diffusion area of the bodily fluid is also reduced, and the optimum absorption performance can be obtained.

  This will be specifically described with reference to FIGS. FIG. 5 is a cross-sectional view when the entire opening 10 overlaps the emboss 11, and FIG. 6 is a cross-sectional view when a part of the opening 10 overlaps the emboss 11. In the overlapping portion 12 between the opening 10 and the emboss 11, as shown in FIGS. 5 and 6, body fluid flows directly into the emboss 11 through the opening 10 and is temporarily stored therein. It is absorbed by the absorber following a path of absorption by the absorber 4 from the peripheral surface. Further, in the portion other than the overlapping portion 12 between the opening 10 and the emboss 11, as shown in FIG. 6, the absorbent body 4 that is not squeezed is interposed in a part of the opening 10. The body fluid that has passed through the top sheet 3 is directly absorbed by the unsqueezed absorbent body 4 and is quickly drawn into the periphery of the emboss 11 by the capillary action of the fibers densified by the squeezing. Following the path of diffusion, it is absorbed by the absorber. Thus, the body fluid that has passed through the liquid-permeable surface sheet 3 through the opening 10 enters the emboss 11 and is temporarily stored, and is absorbed by the unsqueezed absorbent body 4 interposed in the opening 10 and quickly diffuses. In combination, the absorption speed, the amount of reversion, the diffusion area, etc. are improved, and the optimum absorption performance can be obtained.

  On the other hand, if the overlap ratio M is smaller than 17%, it is not preferable because the absorption speed is slowed, the diffusion area is enlarged, and the amount of reversion is increased from the experimental results described in detail later.

  The overlapping ratio M is obtained by taking an enlarged photograph from the surface side of the liquid-permeable surface sheet 3 with a digital microscope (for example, model number VHX-5000, manufactured by Keyence Corporation), and opening 10 and emboss 11 from the photographed image. Can be obtained by measuring the area where the two overlap.

Next, the relationship between the overlapping ratio M and the pitch ratios P _R, will be described with reference to specific examples. 3 and 4, the diameter D _{10 of} the opening 10 is 3.0 mm, the pitch P _{10 of the} opening 10 is 5.4 mm, the diameter D _{11 of} the emboss 11 is 3.9 mm, and the pitch P _{11 of the} emboss 11 is P ₁₁ = 6. It is the figure which showed the positional relationship of the opening 10 and the embossing 11 in the case of .75 mm. Pitch ratio _{P R} in this case is 0.8. FIG. 3 shows a state in which the opening 10 coincides with the center of the emboss 11 at the center, and the overlapping rate M at this time is 21.1%, which is the minimum. On the other hand, FIG. 4 shows a state in which the opening 10 is farthest from the emboss 11 at the central portion, and the overlapping rate M at this time is maximum at 32.9%. Note that the area of the overlapping portion 12 was automatically calculated using a function built in the CAD software when the opening 10 and the emboss 11 were drawn using CAD software built in a personal computer.

In this way, the diameter _{D 11} of the diameter _{D 10} and the pitch _{P 10} and the embossed 11 of apertures 10 and fixed, by changing the pitch of the emboss 11, the pitch ratio _{P R} 0.6,0.7 Table 1 shows the overlap ratio M when the values are changed to 0.8, 0.9, and 1.0. In addition, the result of Table 1 shows that the overlapping rate M is lowest when various changes are made within the practical range when D ₁₀ , P ₁₀ , and D ₁₁ are applied to an actual sanitary napkin. It is determined under the conditions (D ₁₀ = 3.0 mm, P ₁₀ = 5.4 mm, D ₁₁ = 3.9 mm).

As shown in Table 1, as the pitch ratio P _R is increased, the range of overlap ratio M increases. The pitch ratio P _R is the overlap factor M and less than 0.7 too small, hardly overlapped portion 12 is formed, which is not preferable. On the other hand, when the pitch ratio P _R is 1.0, the range of overlap ratio M becomes very large, the displacement of slight misalignment and materials of the feed roller, because that may occur in the case of 0% to not overlap at all, in this case Since it becomes impossible to combine the case where a body fluid enters directly into the emboss 11 through the overlapping portion 12 and the case where the body fluid is absorbed by the absorbent body 4 that is not squeezed, it is not preferable. Thus, the present sanitary napkin 1, as described above, the overlap factor M is always set to 0.7 to 0.9 as the pitch ratio _{P R} as a certain range.

Similarly, the condition (D ₁₀₎ where the overlap ratio M is highest when various changes are made within the practical range when D ₁₀ , P ₁₀ , D ₁₁ is applied to an actual sanitary napkin. = _{3.0 mm,} with _{P 10 = 4.5mm, D 11 =} 4.7mm), was determined overlapping ratio M to the pitch ratio _P R 0.7 to 0.9 above. At this time, the overlap ratio M was greatest when P ₁₁ = 5.0 mm (P _R = 0.9), and the maximum overlap ratio M at that time was 73.1%.

Thus, the overlap factor M at the time of setting the pitch ratio _{P R} to 0.7 to 0.9 is the minimum value of 17.2% (Table 1), the maximum value is 73.1%. Therefore, in this sanitary napkin 1, as described above, the overlapping rate M was set to 17% to 73%. By setting to such a pitch ratio P _R and overlapping ratio M, even when the relative position between the liquid permeable topsheet 3 and the absorbent body 4 is slightly deviated in the production process, the absorption due to the provision of the overlap portion 12 Products with a certain absorption performance that fully exhibits the performance improvement effect can be continuously obtained.

Next, an experiment for comparing the absorption performance when the overlap ratio M is changed will be described. In the experiment, a perforated nonwoven fabric provided with a number of circular apertures 10, 10... Was used as the liquid-permeable surface sheet 3, and a pulp basis weight of 443 g / m ² and a polymer basis weight of 30 g / An m ² pile absorbent was used. The liquid-permeable surface sheet 3 and the absorber 4 are cut into a size of 70 mm × 85 mm, and a range of 5 mm from both side edges of the liquid-permeable surface sheet 3 is joined to the upper layer of the absorber 4 with a hot-melt adhesive. It was used. A circular opening 10 having a diameter D ₁₀ = 2.5 mm and a pitch P ₁₀ = 5.0 mm is formed over the entire surface of the liquid-permeable surface sheet 3, and the absorber 4 has a diameter D _11. A circular emboss 11 having a width of 2.5 mm and a pitch P _{11 of} 5.0 mm is formed over the entire surface. The pitch ratio _{P R} at this time is 1.0. By adjusting the cutting position of the liquid-permeable surface sheet 3, there are three tests in which the overlap ratio M between the opening 10 and the emboss 11 becomes 0%, 50%, and 100% when laminated on the absorber 4. I made a body.

The experiment method is as follows: (1) An injection tube is placed at the center of the side of the liquid-permeable surface sheet 3 of the test body, and the time (seconds) until the artificial menstrual blood 3 cc is completely absorbed from the injection tube is the first time. The area of the plane where the artificial menstrual blood absorbed by the absorber 4 has diffused is marked, and the area (mm ² ) is obtained as the first diffusion area. (2) Three minutes after the start of injection of the artificial menstrual blood, 3 cc of the second artificial menstrual blood is further injected from the injection cylinder, and the second absorption speed and diffusion area are obtained in the same manner. (3) One minute after the start of the second artificial menstrual blood injection, the injection tube is removed, and a filter paper and a weight of 200 g (5 g / cm ² ) are placed on the center of the specimen. (4) After 5 minutes, the weight (g) of the filter paper is measured, and the difference (g) from the weight before the test is determined as the amount of reversion.

  The artificial menstrual blood used was a component of 100 ml of glycerin, 4.6 g of CMC (carboxymethylcellulose sodium), 875 ml of purified water, 10 g of sodium chloride, and 10.7 g of sodium carbonate.

  The results of the experiment are shown in Table 2 and FIGS. The formula in the figure is an approximate expression of a quadratic curve.

  As shown in FIG. 7, the absorption speed tends to increase as the overlap ratio M increases, but tends to decrease when it exceeds approximately 60% to 70%.

  As shown in FIG. 8, the diffusion area tends to decrease as the overlap ratio M increases, but tends to increase slightly when it exceeds around 70%, particularly during the second absorption.

  As shown in FIG. 9, the amount of return tends to decrease as the overlap ratio M increases, but tends to increase slightly when it exceeds approximately 80%.

  As described above, it has been clarified that the absorption performance tends to be slightly lowered when the overlap ratio M is larger than 70% as a boundary.

  Further, when the overlap rate M is reduced, the absorption speed is slowed, the diffusion area is enlarged, and the amount of reversion tends to increase.

[Other examples]
(1) In the above embodiment, the openings 10 of the liquid-permeable surface sheet 3 and the embosses 11 of the absorber 4 are both arranged in a lattice pattern, but as shown in FIG. Any one or both of 11 may be arranged in a staggered manner. The pitch when arranged in a zigzag pattern may be the distance between the centers of the nearest adjacent openings or embosses.

(2) In the above embodiment, the emboss 11 of the absorbent body 4 is formed over the entire surface of the absorbent body 4, but if it is applied to at least the region including the blood drainage port H, the absorbent body 4 There is no need to apply over the entire surface. In this case, the total area of the apertures 10 when the overlap ratio M is determined is the sum of the areas of the liquid-permeable surface sheet 3 existing in the region including the blood drainage port H to which the emboss 10 is provided. To ask for.

(3) Although not shown, by interposing a hydrophilic second sheet between the liquid-permeable surface sheet 3 and the absorbent body 4, the absorption speed is further increased and the amount of return is further reduced. May be. In this case, in a state where the liquid-permeable surface sheet 3 and the second sheet are bonded together, a large number of apertures 10, 10... May be integrally formed in the liquid-permeable surface sheet 3 and the second sheet, or the absorber. In the state where the second sheet is laminated on the skin side of 4, the embossing 11, 11, ... may be imparted to the second sheet and the absorbent body 4 by pressing from the outer surface side of the second sheet, or the second sheet is made into a plurality of sheets. Both of these may be applied simultaneously.

  DESCRIPTION OF SYMBOLS 1 ... Sanitary napkin, 2 ... Impervious back sheet, 3 ... Impervious surface sheet, 4 ... Absorber, 5 ... Encapsulating sheet, 7 ... Side nonwoven fabric, 10 ... Opening, 11 ... Embossing, 12 ... Overlap

Claims (2)

Between the liquid-permeable top sheet and the back sheet in which a large number of apertures are formed, an absorbent body to which a large number of embossments are imparted by pressing from the skin side is interposed, and the apertures and the embossments are thick. An absorbent article arranged to overlap in a predetermined proportion in the direction,
Wherein both apertures and embossing plane shape is circular, with a diameter _{D 10} of the apertures are 0.5 mm to 3 mm, the pitch _{P 10} of the opening is of a diameter of the aperture _{D 10} 1 set to .5 times to 1.8 times, and the diameter _{D 11} of the embossed is 1.3 times to 2 times the diameter _{D 10} of the apertures, the apertures are arranged in a grid pattern or a staggered pattern, The embosses are arranged in a lattice or zigzag pattern,
Under pitch P _10, the conditions of the diameter D ₁₀ of the diameter D ₁₁ and the opening 10 of the embossing were set in the above range of the aperture, pitch P ₁₁ of the embossments from the following equation (1) by being pitch ratio _{P R} is set to be 0.7 to 0.9,
Pitch ratio P _R = (Pitch P _{10 of the} opening 10) / (Pitch P _{11 of the} emboss ₁₁ ) (1)
In a circle with a diameter of 50 mm centered on the body fluid discharge site of the wearer, obtained from the formula : (total area of overlapping portion where the opening and embossing overlap in the thickness direction) / (total area of the opening) × 100 An absorptive article characterized in that the overlapping ratio of the opening and the embossing is set to 17% to 73%. The absorbent article of the embossments claim 1 Symbol placement has been granted in a region including at least a body fluid drainage site.

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