JP2018166946A - Composite sheet and absorbent article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite sheet capable of quickly permeating a body fluid and having excellent breathability. SOLUTION: The composite sheet includes a first fiber layer and a second fiber layer arranged under the first fiber layer, and the first fiber layer has a flat plate shape and has a high density region. The second fiber layer has a plurality of convex portions protruding toward the first fiber layer side, and the plurality of convex portions have a low density region having a fiber density lower than that of the high density region. The top of at least a part of the convex portion is in contact with the high-density region of the first fiber layer. [Selection diagram] FIG. 1A

Description

  The present invention relates to a composite sheet and an absorbent article.

  Conventionally, in an absorbent article such as an incontinence pad, a panty liner, and a sanitary napkin, a configuration in which an absorbent body is provided between a liquid-permeable top sheet and an impermeable back sheet is known. And as a liquid-permeable surface sheet, there is known a composite of two fiber layers in consideration of rapid permeation of body fluid.

  For example, Patent Document 1 includes a hydrophobic nonwoven fabric that forms a first surface and a hydrophilic nonwoven fabric that forms a second surface, and at least unevenness is formed on the hydrophilic nonwoven fabric. The hydrophilic non-woven fabric has a fiber density higher than other portions and includes a protruding portion that protrudes from the hydrophobic non-woven fabric, and the hydrophobic non-woven fabric and the hydrophilic non-woven fabric are at least part of the protruding portions. A composite sheet for absorbent articles that is in direct contact with each other in the part is disclosed.

  Patent Document 2 discloses a non-woven fabric for absorbent articles composed of at least two fiber layers, and a plurality of convex portions projecting in the direction of the first surface and a first portion provided between the convex portions. A plurality of grooves recessed in the direction of the two surfaces, the groove provided discontinuously in the first recess provided with the first bottom located on the second surface side, A plurality of second recesses recessed from the first bottom toward the second surface, wherein the second recess includes a second bottom having the highest fiber density among the nonwoven fabrics. Yes.

JP 2017-12319 A Japanese Patent Laid-Open No. 2006-220987

  Patent Document 1 discloses that the fibers of the convex portion 6B of the hydrophilic nonwoven fabric arranged on the lower side are dense and have high water absorption, and the fibers of the concave portion 7A of the hydrophobic nonwoven fabric arranged on the upper side. It is described that the movement of moisture from the first surface to the second surface side of the composite sheet can be promoted due to the fact that the water is permeable and the water permeability is high. However, since the fibers are concentrated in the convex portion 6A of the hydrophobic non-woven fabric, the body fluid tends to stay in the portion, and the moisture hardly transfers to the concave portion 7B of the hydrophilic non-woven fabric.

  The nonwoven fabric disclosed in Patent Document 2 is configured to have a fiber density gradient in which the fiber density increases from the first surface to the second surface. However, in the nonwoven fabric of Patent Document 2, since the two fiber layers are in close contact with each other, the air permeability between the layers cannot be said to be good, and there is a problem that reversion tends to occur.

  In view of the above points, an object of the present invention is to provide a composite sheet that can quickly pass through body fluids and has excellent air permeability.

  In order to solve the above problems, a first aspect of the present invention is a composite sheet including a first fiber layer and a second fiber layer disposed below the first fiber layer, wherein the first fiber layer is the first sheet. The fiber layer is flat, has a high density region, and a low density region having a fiber density lower than the high density region, and the second fiber layer has a plurality of protrusions protruding toward the first fiber layer side. It has a convex part and the top part of the convex part of at least one part of the said several convex part is in contact with the said high-density area | region of the said 1st fiber layer.

  According to the first aspect, the first fiber layer has the high density region and the low density region, so that the body fluid moves from the low density region to the high density region in the first fiber layer. It becomes easy to do. In addition, the second fiber layer has a plurality of protrusions protruding toward the first fiber layer, and at least some of the tops of the protrusions are high-density regions of the first fiber layer in which body fluid is likely to collect. The body fluid can be quickly transferred from the first fiber layer to the second fiber layer.

  Furthermore, since the first fiber layer is flat, there is a space between the first fiber layer and the second fiber layer, and the air permeability is good. Therefore, even when the body fluid remains in the low-density region or the like of the first fiber layer, it is easy to dry, and unpleasant feeling due to stickiness can be prevented. Moreover, since there is little area which a 1st fiber layer and a 2nd fiber layer contact, the reverse return of the bodily fluid from a 2nd fiber layer to a 1st fiber layer can be prevented, and a feeling of wear can be improved.

  In the second embodiment of the present invention, the fiber density of the convex portion is higher than the fiber density of the high-density region.

  According to said 2nd form, since the fiber density of the convex part of a 2nd fiber layer is higher than the fiber density of the high-density area | region of a 1st fiber layer, from a 1st fiber layer to a 2nd fiber layer The transfer of body fluid proceeds better.

  In the third aspect of the present invention, the second fiber layer has a concave portion between the plurality of convex portions, and the fiber density of the concave portion is higher than the fiber density of the convex portion.

  According to the said 3rd form, the transfer of the bodily fluid from the convex part in a 2nd fiber layer to a recessed part becomes easy. Thereby, the bodily fluid which has migrated from the first fiber layer can be satisfactorily migrated to a lower layer (absorber, etc.).

  In the fourth embodiment of the present invention, at least some of the tops of the plurality of convex portions are arranged at least partially in the low-density region of the first fiber layer in plan view. Yes.

  According to the fourth embodiment, the second fiber layer can be in contact with the low-density region of the first fiber layer. Thereby, even when a bodily fluid remains in the low density region, the bodily fluid is absorbed from the low density region of the first fiber layer to the convex portion of the second fiber layer, and stickiness can be prevented.

  In the fifth aspect of the present invention, a top portion of the convex portion arranged at least partially in the low density region is separated from the first fiber layer.

  According to the fifth aspect, among the plurality of convex portions of the second fiber layer, the height of the convex portions that are not in contact with the high-density region of the first fiber layer is lower, so the first fiber layer and the first The space between the two fiber layers can be increased. Thereby, air permeability can be further improved.

  In the sixth embodiment of the present invention, the low density region has an aperture.

  According to the sixth aspect, the surface area of the first fiber layer is reduced by forming the opening in the first fiber layer. Thereby, since the area which a 1st fiber layer and skin contact is not small, the discomfort with respect to skin can be reduced and air permeability can also be improved.

  In the seventh aspect of the present invention, at least a part of the plurality of convex portions is formed so as to protrude from the aperture portion.

  According to the seventh aspect, when the composite sheet is compressed in the thickness direction, the convex portion of the second fiber layer can protrude from the opening of the first fiber layer and contact the first fiber layer. It becomes. Therefore, even when the body fluid remains in the hole portion, the body fluid can be easily transferred from the first fiber layer to the second fiber layer.

  The eighth aspect of the present invention is a composite sheet according to any one of the first to seventh aspects, a liquid-impermeable back sheet, and between the top sheet and the back sheet as a top sheet. It is an absorbent article provided with the main body which has the provided absorber.

  According to the eighth aspect, it is possible to provide an absorbent article including a composite sheet that exhibits the above-described effects.

  According to one embodiment of the present invention, it is possible to provide a composite sheet that can quickly permeate body fluid and has excellent air permeability.

It is a disassembled perspective view of the composite sheet by the 1st form of this invention. It is a perspective view of the composite sheet by the 1st form of this invention. It is typical sectional drawing for demonstrating the function of the composite sheet by the 1st form of this invention. It is typical sectional drawing for demonstrating the function of the composite sheet by the modification of the 1st form of this invention. It is typical sectional drawing for demonstrating the function of the composite sheet by the modification of the 1st form of this invention. It is a disassembled perspective view of the composite sheet by the 2nd form of this invention. It is a perspective view of the composite sheet by the 2nd form of this invention. It is a figure for demonstrating the shape of the 2nd fiber layer in the 3rd form of this invention. It is a top view of the composite sheet using the 2nd fiber layer in the 3rd form of the present invention. It is a figure for demonstrating the shape of the 2nd fiber layer in the 4th form of this invention. It is a top view of the composite sheet using the 2nd fiber layer in the 4th form of the present invention. It is a figure for demonstrating the shape of the 2nd fiber layer in the 5th form of this invention. It is a top view of the composite sheet using the 2nd fiber layer in the 5th form of this invention. It is typical sectional drawing for demonstrating the function of the composite sheet by the 4th and 5th form of this invention. It is typical sectional drawing for demonstrating the function of the composite sheet by the 4th and 5th form of this invention. It is a schematic diagram of the apparatus which manufactures the composite sheet by one form of this invention. It is a partially broken view of the absorbent article by one form of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments.

(Composite sheet)
FIG. 1 shows a composite sheet 1 according to an embodiment of the present invention. FIG. 1A is a schematic exploded perspective view of the composite sheet 1, and FIG. 1B is a schematic perspective view of the composite sheet 1. In the drawings, the x direction indicates the width direction of the absorbent article when the composite sheet 1 is used for a flat absorbent article having an elongated shape (FIG. 10), and the y direction is orthogonal to the x direction. The front-rear direction of the absorbent article refers to the z direction, which is the direction orthogonal to the surface of the absorbent article. Note that the x direction and the y direction can be interchanged.

  As shown in FIGS. 1A and 1B, the composite sheet 1 includes a first fiber layer 10 and a second fiber layer 20 disposed below the first fiber layer 10. Each of the first fiber layer 10 and the second fiber layer 20 is a layer including an aggregate of fibers.

(First fiber layer)
The first fiber layer 10 has a flat plate shape, and has a high density region 12 and a low density region 14 having a fiber density lower than that of the high density region 12. In FIGS. 1A and 1B, the high density region 12 is dark and the low density region 14 is colored lighter than the high density region 12. Since the first fiber layer 10 has such regions with different fiber densities, the body fluid flowing from the upper surface side of the first fiber layer 10 flows into the low density region 14 where the space into which the body fluid enters is larger. It's easy to do. However, since the capillary phenomenon is more remarkable in the high-density region 12 than in the low-density region 14, a force (capillary force) that draws liquid from a region having a low fiber density to a region having a high fiber density is generated. As a result, body fluid (including urine, vaginal discharge, menstrual blood, etc.) moves from the low density region 14 to the high density region 12 in the first fiber layer 10.

  1A and 1B, the high-density region 12 extends in a regular pattern in a lattice shape. That is, the high density region 12 is a combination of a region group including a plurality of linear regions 12a extending at intervals in the x direction and a region group including a plurality of linear regions 12b extending at intervals in the y direction. And have a crossing structure. The low density region 14 is formed in a region other than the high density region 12. In the illustrated form, a low density region 14 is formed in a region surrounded by the high density region 12.

  However, the arrangement of the high density region 12 and the low density region 14 is not limited to the illustrated form. For example, the high density region 12 may be formed by one region group among the above-described region groups. Further, the linear regions 12a and 12b of the above two region groups do not have to be orthogonal to each other, and may intersect at an angle of, for example, 15 to 75 °. Even within the same region group, the extending directions of the respective linear regions may be different from each other, and thereby adjacent linear regions may overlap. Further, each linear region in the same region group may not extend linearly, and may be bent or meandered. The widths of the linear regions may be different depending on each linear region, or the widths may vary in the same linear region.

  Moreover, the high-density area | region 12 does not need to contain a linear area | region, For example, the area | region which has arbitrary shapes may be arrange | positioned linearly or irregularly, spacing apart. Furthermore, the arrangement of the high-density region 12 and the low-density region 14 can be changed. However, the strength of the first fiber layer 10 can be increased by the high-density regions 12 extending in a lattice pattern as in the illustrated form. In addition, in both the x direction and the y direction of the first fiber layer 10, it can be avoided that the low density region 14 is greatly separated from the high density region 12, so that the body fluid is transferred from the low density region 14 to the high density region 12. Can be improved.

  The ratio of the total area of the high density region 12 and the total area of the low density region 14 in the first fiber layer 10 is preferably 3: 7 to 6: 4, and is 4: 6 to 5: 5. More preferably. By setting the ratio of the total area of the high-density regions 12 and the total area of the low-density regions 14 to 3: 7 or more, it is possible to prevent the low-density regions 14 from being greatly separated from the high-density regions 12. The body fluid from the low density region 14 to the high density region 12 can be favorably transferred in one fiber layer 10. On the other hand, by setting it as 6: 4 or less, it can prevent that the area | region far away from the contact location with the convex part 21 of the 2nd fiber layer 20 among the high-density area | region 12 is formed, and the 1st fiber layer 10 From the body fluid to the second fiber layer 20 can be improved.

  The first fiber layer 10 may be a layer containing an aggregate of fibers, and may be a woven fabric or a non-woven fabric, but is preferably a non-woven fabric because regions having different fiber densities can be easily formed. . Examples of the fibers constituting the nonwoven fabric include olefins such as polyethylene and polypropylene, synthetic fibers such as polyester and polyamide, regenerated fibers such as rayon and cupra, blended fibers thereof, and natural fibers such as cotton alone or 2 It can be used in combination of more than one species. Especially, since the force which absorbs a bodily fluid is strong and the touch is good, it is preferable to use cotton for the 1st fiber layer 10.

  When the first fiber layer 10 is a nonwoven fabric, examples of the processing method include a spunlace method, a spunbond method, a thermal bond method, a chemical bond method, a melt blown method, and a needle punch method. When cotton is used as the fiber, it is preferable to use a spunlace method in which the fibers can be strongly entangled because the fibers cannot be bonded using heat fusion. Moreover, the high density area | region 12 and the low density area | region 14 of the 1st fiber layer 10 can be formed by allowing the formed layered fiber assembly to pass through a pair of pressure rolls, at least one of which has irregularities. .

  In addition, the high density area | region 12 can be made into an area | region where a fiber density is higher than the average fiber density of the 1st fiber layer 10, and the low density area | region 14 is a fiber rather than the average fiber density of the 1st fiber layer 10. A region having a low density can be obtained. The high-density region 12 is preferably a region having a fiber density that is 1.25 times or more the average fiber density of the first fiber layer 10 and less than 1.25 times the average fiber density of the first fiber layer 10. It is preferable that the region has a fiber density of.

Fiber density of the high-density regions 12 of the first fiber layer 10 is preferable to be 80~500g / ^{m 3,} more preferably a 100 to 300 g / ^{m 3.} The fiber density of the low density regions 14 of the first fiber layer 10 is preferable to be 30 to 400 g / ^{m 3,} more preferably a 50 to 200 g / ^{m 3.} The fiber density of the overall average of the first fiber layer 10 is preferable to be 30 to 500 g / ^{m 3,} more preferably a 50 to 300 g / ^{m 3.} The value of the ratio of the fiber density of the high density region 12 of the first fiber layer to the fiber density of the low density region 14 of the first fiber layer ((fiber density of the high density region of the first fiber layer) / (first fiber) The fiber density in the low density region of the layer)) is preferably 1.5 or more, and more preferably 1.7 or more.

  Moreover, the thickness of the 1st fiber layer 10 is preferable in it being 0.1-0.5 mm, and it is more preferable in it being 0.2-0.3 mm.

  Further, the first fiber layer 10 may be provided with irregularities by pressing or the like. However, even when unevenness is provided, the shape is such that a space is formed between the first fiber layer 10 and the second fiber layer 20. Thereby, the structure which permeate | transmitted bodily fluid quickly and was excellent in air permeability can be obtained. In addition, it is preferable that the surface of the 1st fiber layer 10 is not provided with an unevenness | corrugation from a viewpoint of making the touch favorable.

(Second fiber layer)
As shown in FIGS. 1A and 1B, the second fiber layer 20 has a plurality of convex portions 21 protruding toward the first fiber layer 10. In the illustrated form, the plurality of convex portions 21 are formed as a plurality of flange portions extending in the y direction. Concave portions 22 are formed between the convex portions 21, and in the illustrated form, the plurality of concave portions 22 are formed as a plurality of groove portions formed between the plurality of flange portions and extending in the y direction.

  As shown in FIG. 1B, the top portion 21 a ′ of at least some of the convex portions 21 a among the plurality of convex portions 21 is in contact with the first fiber layer 10. Thereby, it can transfer to the 2nd fiber layer 20 quickly from the high-density area | region 12 which is the area | region where the body fluid was collected in the 1st fiber layer 10, and a body fluid can be absorbed rapidly. In the illustrated form, the heights of the plurality of convex portions 21 are the same, but the heights of the plurality of convex portions 21 may be different from each other. Further, the height of each convex portion 21 may vary along the y direction.

  Further, in the illustrated form, the top portions 21 b ′ of some of the convex portions 21 b of the plurality of convex portions 21 are in partial contact with the high-density region 12. Moreover, these convex parts 21b do not need to contact the high-density area | region 12, and do not need to contact 1st fiber layer 10 itself.

  The top portion 21 a ′ of the convex portion 21 a of the second fiber layer 20 in contact with the high density region 12 may be bonded to the high density region 12 of the first fiber layer 10. In that case, both layers may be bonded by an adhesive, for example a hot melt adhesive. Moreover, adhesion by thermal fusion can be performed by adding thermoplastic synthetic fibers to the first fiber layer 10 and / or the second fiber layer 20, or by adding a binder.

  The fiber density of the convex portions 21 of the second fiber layer 20 is preferably larger than the fiber density of the high-density region 12 of the first fiber layer 10. As a result, the force (capillary force) for drawing body fluid from the first fiber layer 10 to the second fiber layer 20 is increased, so that the body fluid can be quickly transferred from the high-density region 12 of the first fiber layer 10 to the second fiber layer 20. It can be carried out.

  In the second fiber layer 20, the fiber density of the recesses 22 is preferably higher than the fiber density of the protrusions 21. Thereby, it becomes easy to introduce | transduce the bodily fluid which has transferred to the convex part 21 of the 2nd fiber layer 20 from the 1st fiber layer 10 further to the recessed part 22 with capillary force.

  Further, as shown in FIG. 1B, since the first fiber layer 10 has a flat plate shape and the second fiber layer has an uneven structure, it is between the first fiber layer 10 and the second fiber layer 20. A space S is formed at least between the first fiber layer 10 and the recess 22 of the second fiber layer 20. Thereby, the air permeability in a composite sheet improves. Therefore, even when a body fluid remains in the first fiber layer 10, it becomes possible to dry quickly, and a sticky feeling (uncomfortable feeling) caused by the body fluid touching the skin can be suppressed. Moreover, even if the body fluid remains in the second fiber layer 20, the drying is similarly accelerated, so that the reversal when the composite sheet is strongly compressed can be reduced. With the above-described configuration, the body fluid can be transferred quickly, and the drying proceeds quickly. As a result, it is possible to provide the composite sheet 1 that provides a comfortable wearing feeling.

  Similar to the first fiber layer 10, the second fiber layer 20 may be a layer containing an aggregate of fibers, and may be a woven fabric or a non-woven fabric, but is preferably a non-woven fabric. As the fibers used for the nonwoven fabric, the same fibers as those described in the first fiber layer 10 can be used. Moreover, the processing method at the time of making the layer of the 2nd fiber layer 20 into a nonwoven fabric can also use the method similar to what was demonstrated with the 1st fiber layer 10. FIG.

  The convex part 21 and the recessed part 22 of the 2nd fiber layer 20 can be formed by pressing (embossing), for example. The pressing can be formed by passing the layered fiber assembly between a pair of pressure rolls, for example, a roll having an uneven shape and a flat roll. By such pressing, the fiber density of the concave portion 22 can be made higher than the fiber density of the convex portion 21 as described above.

Fiber density of the convex portion 21 of the second fiber layer 20 is preferable to be 100 to 500 g / ^{m 3,} more preferably a 150 to 350 g / ^{m 3.} The fiber density of the recessed portion 22 of the second fiber layer 20 is preferable to be 200 to 800 g / ^{m 3,} more preferably a 250~500g / ^{m 3.} The fiber density of the overall average of the second fiber layer 20 is preferable to be 150~450g / ^{m 3,} more preferably a 200 to 400 g / ^{m 3.} Value of ratio of fiber density of concave portion 22 of second fiber layer 20 and fiber density of convex portion 21 of second fiber layer 20 ((fiber density of concave portion 22 of second fiber layer 20) / (second fiber layer) The fiber density of the 20 convex portions 21)) is preferably 1.1 or more, and more preferably 1.3 or more.

  The value of the ratio of the fiber density of the convex portion 21 of the second fiber layer 20 and the fiber density of the high-density region 12 of the first fiber layer 10 ((fiber density of the convex portion 21 of the second fiber layer 20) / (first The fiber density of the high-density region 12 of one fiber layer 10) is preferably 1.05 or more, and more preferably 1.1 or more.

  The second fiber layer 20 can be a non-woven fabric using the fibers described for the first fiber layer 10. As the method for forming the nonwoven fabric as the second fiber layer 20, the formation method described for the first fiber layer 10 can also be used. In addition, it is preferable that the thickness of the convex portion 21 of the second fiber layer 20 is larger than the thickness of the first fiber layer 10.

(Description of the effect of this embodiment)
Next, the effect of this embodiment will be described in more detail below. FIG. 2 shows a schematic cross-sectional view (cross-sectional view taken along line II) of the composite sheet 1 of FIG. 1B cut in the x direction. In FIG. 2, the composite sheet 1 is shown as a state in which the composite sheet 1 and the absorbent body 4 thereunder are combined.

  When the composite sheet 1 of this embodiment is used as a top sheet of an absorbent article, the upper side in FIG. 2 is the wearer's skin and the body fluid is released. Here, the capillary phenomenon in the fiber layer occurs more significantly in the high density region 12 than in the low density region 14. Therefore, when the body fluid comes into contact with the first fiber layer 10, the body fluid moves from the low density region 14 to the high density region 12 by capillary action in the first fiber layer 10. And since the high-density area | region 12 of the 1st fiber layer 10 is contacting the convex part 21 of the 2nd fiber layer 20, the bodily fluid which has moved to the high-density area | region 12 of the 1st fiber layer 10 is 2nd fiber layer. The transition is made to 20 convex portions 21. Furthermore, the body fluid moves from the convex portion 21 to the concave portion 22 in the second fiber layer 20, and then migrates from the concave portion 22 to the third layer provided therebelow, in the illustrated form, the absorbent body. The transfer of these body fluids is indicated by arrows in FIG.

  By being able to transfer bodily fluids mainly through the above-mentioned route, bodily fluids can be quickly absorbed into the absorbent body 4 and the amount of bodily fluids contained in the first fiber layer 10 that is in direct contact with the wearer's skin can be quickly reduced. Can do.

  In the composite sheet 1, the fiber density is in the order of the low density region 14 of the first fiber layer 10, the high density region 12 of the second fiber density, the convex portion 21 of the second fiber layer 20, and the concave portion 22 of the second fiber layer 20. It is preferable that it is high. This makes it easier to absorb the path as indicated by the arrow. In addition, it is preferable that the fiber density of the absorbent body 4 is larger than the fiber density of the recess 22 of the second fiber layer 20 because the force for drawing body fluid from the second fiber layer 20 to the absorbent body 4 becomes larger.

  The composite sheet 1 is configured by combining a flat plate-like first fiber layer 10 and a second fiber layer 20 having a plurality of convex portions 21. Therefore, a space S is formed between the first fiber layer 10 and the second fiber layer 20, and air can easily pass between the fiber layers. Thereby, while being able to permeate | transmit a bodily fluid quickly, it is the composite sheet 1 which is excellent also in air permeability.

  In addition, in any fiber layer of the 1st fiber layer 10 and the 2nd fiber layer 20, it is preferable that a cotton is included as a fiber from a viewpoint of the absorptivity of a bodily fluid. In particular, since the touch is good, it is preferable that the first fiber layer 10 in direct contact with the wearer's skin contains cotton. However, cotton generally has high water retention and has a strong function of retaining body fluids. Therefore, in the conventional configuration, when the first fiber layer 10 includes cotton, the body fluid tends to remain in the first fiber layer 10 and it may be easy to feel stickiness.

  In contrast, the first fiber layer 10 has a high density region 12 and a low density region 14, and at least some of the plurality of convex portions 21 of the second fiber layer 20 have a high fiber density of the first fiber layer 10. With the above-described configuration in contact with the region, the body fluid can be quickly transferred from the first fiber layer 10 to the second fiber layer 20. Thereby, the composite sheet which suppressed the stickiness and improved the wearing feeling can be obtained while taking advantage of the water absorption and the touch that cotton originally has.

(Modification of the first embodiment)
3A and 3B are schematic cross-sectional views of modifications of the composite sheet 1 shown in FIGS. 1A, 1B, and 2. FIG. 3A shows a normal state of the composite sheet 1, and FIG. 3B shows a state where the composite sheet 1 is compressed in the thickness direction.

  In the composite sheet 1 shown in FIGS. 3A and 3B, the height of some of the convex portions 21b among the plurality of convex portions 21 formed on the second fiber layer 20 is lower than the height of the convex portions 21a on both sides thereof. This is different from the above-described composite sheet. As described above, the height of some of the convex portions 21 b is low, so that the top portion 21 b ′ of the convex portion 21 b is separated from the first fiber layer 10. Thereby, since the space between the 1st fiber layer 10 and the 2nd fiber layer 20 becomes large, air permeability improves.

  In such a form in which the height of some of the convex portions 21b is low, the top portion 21b 'of the convex portion 21b having a low height is disposed in the low density region 14 of the first fiber layer in plan view. It is preferable. With such a configuration, when the composite sheet 1 is compressed as shown in FIG. 3B, the convex portion 21 b can come into contact with the low density region 14, so that the body fluid is applied to the low density region 14 of the first fiber layer 10. Even when U remains, the bodily fluid U can be directly absorbed by the convex portion 21b.

  In addition, the value of the ratio of the height b of the convex part 21b in FIG. 3A and the height a of the convex part 21a provided in the both sides is low of the 1st fiber layer 10 when the composite sheet 1 is compressed. From the viewpoint of enabling direct absorption of body fluid U from the density region 14, it is preferably 0.5 or more. Further, from the viewpoint of improving air permeability, it is preferably 0.8 or less.

(Composite sheet according to the second form)
4A and 4B show a second form of the composite sheet according to the present invention. 4A is a schematic exploded perspective view of the composite sheet 201, and FIG. 4B is a schematic perspective view of the composite sheet 201.

  4A and 4B, the composite sheet 201 includes a first fiber layer 210 and a second fiber layer 220. The first fiber layer 210 is composed of a high-density region 212 and a high-density region 212. And a low density region 214 having a low fiber density. The second fiber layer 220 has a plurality of convex portions 221 protruding toward the first fiber layer 210 and a plurality of concave portions 222 formed therebetween, and the top of at least some of the convex portions 221. Is in contact with the high density region 212 of the first fiber layer 210. However, it differs from the embodiment shown in FIGS. 1A and 1B in that the low density region 214 of the first fiber layer 210 has the apertures 216.

The opening portion 216 refers to a region where there is no fiber having an area of 25,000 μm ² or more in plan view. In addition, the total area of the apertures 216 in the first fiber layer 210 is preferably 30% or less with respect to the entire area of the first fiber layer 210. By setting it as this range, it can prevent that the 2nd fiber layer 120 exposes too much and impairs the touch. The shape of the opening 216 may be a circle or a polygon such as a quadrangle as illustrated. Moreover, when the opening part 216 is circular, it is preferable that a diameter is 0.3-3 mm.

  For example, when the first fiber layer 201 is formed as a non-woven fabric as described above, the opening 216 can be formed by designing so as to form a region without fibers. Moreover, after forming the nonwoven fabric used as a 1st fiber layer, you may form by a needle punch etc. In the former case, the shape of the opening 216 is an indefinite shape having no clear contour.

  By forming the opening 216 in the low density region 214, when the first fiber layer 210 hits the skin, the area in contact with the skin can be reduced. Therefore, even if the composite sheet 201 hits the skin with the body fluid remaining in the first fiber layer 210, it becomes difficult to feel stickiness due to the body fluid. Moreover, since the air permeability of the composite sheet 201 is improved by the presence of the opening portion 116, it can be quickly dried even if the body fluid remains in the first fiber layer 210.

  4B, in the composite sheet 201 obtained by stacking the first fiber layer 210 and the second fiber layer 220, a part of the convex portion 221 of the second fiber layer 220 is the first fiber in plan view. The layer 210 is exposed from the opening 216.

(Composite sheet according to the third embodiment)
With reference to FIG. 5A and FIG. 5B, the composite sheet 301 by the 3rd form is demonstrated. FIG. 5A is a perspective view of the second fiber layer 320 in the composite sheet 301 according to the third embodiment, and FIG. 5B is a third embodiment in which the first fiber layer 310 and the second fiber layer 320 are laminated. 3 is a top view of a composite sheet 301. FIG.

  The composite sheet 301 also includes a first fiber layer 310 and a second fiber layer 320, similar to the composite sheets 1 and 201 described above. The first fiber layer 310 includes a high-density region 312 and a high-density region 312. And a low density region 314 having a low fiber density. In addition, the second fiber layer 320 has a plurality of convex portions 321 protruding toward the first fiber layer 310, and at least a top portion of the convex portions 321 is a high-density region 312 of the first fiber layer 310. Is different from the composite sheet 201 (FIGS. 4A and 4B) in that the configuration of the second fiber layer 320 is different.

  The second fiber layer 320 shown in FIG. 5A is the same as the second fiber layer 20 of the composite sheet 1 in that it has a plurality of hook-shaped protrusions 321c that are separated from each other and extend in the y direction. Further, a plurality of convex portions 321d extending apart from each other are also provided in the x direction. That is, the second fiber layer 320 has a lattice-like convex portion including the convex portion 321c and the convex portion 321d. Such a lattice-like convex portion increases the shape retention of the second fiber layer 320, and can maintain a structure having irregularities even against a force such as compression.

  FIG. 5B shows a top view of the composite sheet 301 in which the second fiber layer 320 shown in FIG. 5A is laminated with the first fiber layer 310. As shown in FIG. 5B, in the composite sheet 301, a part of the convex portion 321 of the second fiber layer 320 is exposed from the opening portion 316 of the first fiber layer 310.

(Composite sheet according to the fourth embodiment)
With reference to FIG. 6A and FIG. 6B, the composite sheet 401 by the 4th form is demonstrated. 6A is a perspective view of the second fiber layer 420 in the composite sheet 401 according to the fourth embodiment, and FIG. 6B is according to the fourth embodiment in which the first fiber layer 410 and the second fiber layer 420 are laminated. 3 is a top view of a composite sheet 401. FIG.

  The composite sheet 401 also includes a first fiber layer 410 and a second fiber layer 420 as in the above-described composite sheet. The first fiber layer 410 has a fiber density higher than that of the high-density region 412 and the high-density region 412. And a low low density region 414. In addition, the second fiber layer 420 has a plurality of convex portions 421 that protrude toward the first fiber layer 410, and the top of at least some of the convex portions 421 is the high-density region 412 of the first fiber layer 410. Is different from the composite sheet 201 (FIGS. 4A and 4B) in that the configuration of the second fiber layer 420 is different.

  The second fiber layer 420 is not provided with the ridge-shaped protrusions provided in the composite sheet 201 or the like, and a plurality of independent protrusions 421 are continuously arranged separately from each other in the x direction and the y direction. Has been.

  FIG. 6B shows a top view of the composite sheet 401 in which the second fiber layer 420 shown in FIG. 6A is laminated with the first fiber layer 410. As shown in FIG. 6B, in the composite sheet 401, a part of the convex portion 421 of the second fiber layer 430 is exposed from the opening portion 416 of the first fiber layer 410.

  (Composite sheet according to the fifth embodiment)

  With reference to FIG. 7A and FIG. 7B, the composite sheet 501 by the 5th form is demonstrated. 7A is a perspective view of the second fiber layer 520 in the composite sheet 501 according to the fifth embodiment, and FIG. 7B is according to the fifth embodiment in which the first fiber layer 510 and the second fiber layer 520 are laminated. 4 is a top view of a composite sheet 501. FIG.

  The composite sheet 501 also includes a first fiber layer 510 and a second fiber layer 520, as in the above-described composite sheet. The first fiber layer 510 has a fiber density higher than that of the high-density region 512 and the high-density region 512. And a low low density region 514. The second fiber layer 520 has a plurality of protrusions 521 protruding toward the first fiber layer 510, and at least some of the tops of the protrusions 521 are high-density regions 512 of the first fiber layer 510. Is different from the composite sheet 201 (FIGS. 4A and 4B) and the like in that the configuration of the second fiber layer 520 is different.

  The second fiber layer 520 of the composite sheet 501 shown in FIG. 7A includes the configuration of the second fiber layer 320 of the composite sheet 301 according to the third embodiment (FIG. 5A) and the second fiber layer of the composite sheet 401 according to the fourth embodiment. Each of the configurations 420 (FIG. 6A) is incorporated. That is, in addition to the grid-like convex portions 521c and 521d extending in the x-direction and the y-direction, respectively, there are independent convex portions 521e formed in the lattice.

  FIG. 7B shows a top view of the structure of the composite sheet 401 in which the second fiber layer 420 shown in FIG. 7A is laminated with the first fiber layer 410. As shown in FIG. 7B, in the composite sheet 401, the first fiber layer out of the opening portion 416 of the first fiber layer 410 and a part of the convex portion 421e of the second fiber layer 410 and the top portion of the convex portion 421e. A portion of 410 that is not in contact with the high density region 412 is exposed.

(Explanation of effects according to fourth and fifth embodiments)
About the function by the structure provided with the 2nd fiber layer containing a plurality of independent convex parts like the above-mentioned 4th form (Drawing 6A and 6B) and 5th form (Drawing 7A and 7B), This will be described with reference to FIGS. 8A and 8B.

  8A and 8B, the composite sheet 401 shown in FIGS. 6A and 6B is illustrated and described as an example. 8A is a schematic cross-sectional view of the composite sheet 401 (cross-sectional view taken along the line II-II in FIG. 6B), and FIG. 8B is a schematic cross-sectional view showing a state in which the composite sheet 401 of FIG. 8A is compressed. is there.

  As shown in FIG. 8A, the first fiber layer 410 has an opening 416 in the low density region 414. The convex portion 421a of the second fiber layer 420 is in contact with the high-density region 412, and the convex portion 421b is disposed below the opening portion 416 and can protrude upward from the opening portion 416. Yes.

  As described above, the body fluid easily moves from the low density region 414 to the high density region 412, but when the hole portion 416 is provided, the body fluid U may remain in the hole portion 416. is there. Even in such a case, if the convex portion 421b is arranged at a position corresponding to the opening portion 416 as shown in the figure, the composite sheet 401 receives the force F and is compressed during use of the composite sheet 401. Thus, the convex portion 421b protrudes from the opening portion 416. Thereby, the bodily fluid U left in the opening portion 416 can be reliably absorbed by the convex portion 421b.

  The composite sheet 501 shown in FIGS. 7A and 7B can achieve the same effect as described above. In the case of the composite sheet 501, since the lattice-like convex portions 521c and 521d are formed, the body fluid is retained even when the body fluid remains in the opening portion 516 of the first fiber layer 510 while maintaining shape retention. Can be quickly absorbed from the first fiber layer 510 to the second fiber layer 520.

  As described above, the composite sheet according to the present embodiment can quickly permeate body fluids and has excellent air permeability. Therefore, an absorbent article that absorbs body fluids such as urine with low viscosity and high discharge speed, for example, for women It can be suitably used as a surface sheet of the incontinence pad.

(Manufacture of composite sheets)
The composite sheet according to the present embodiment can be manufactured by combining (stacking or superposing) the first fiber aggregate that becomes the first fiber layer and the second fiber aggregate that constitutes the second fiber layer. . This composite includes bonding the first fiber layer and the second fiber layer.

  FIG. 9 schematically shows a manufacturing apparatus 50 for the composite sheet 201 shown in FIGS. 4A and 4B as an example. The illustrated apparatus 50 is a pair of pressure rolls for forming a first roll 51 and a second roll 52, and a first fiber layer 210, which are a pair of pressure rolls for forming the second fiber layer 220. A fourth roll 54 and a fifth roll 55 and a third roll 53 for combining the first fiber layer 210 and the second fiber layer 220 are provided.

  In the apparatus 50, when the second fiber aggregate 42 passes between the first roll 51 and the second roll 52, the convex portion 221 and the concave portion 222 corresponding to the shape of the roll in the second fiber aggregate 42. (FIGS. 4A and 4B) can be formed. At that time, a convex portion 221 is formed on the second fiber assembly 42 at a position where the peak 51A of the first roll 51 and the valley 52B of the second roll 52 mesh. In addition, a recess 222 is formed in the second fiber assembly 42 at a position where the valley 51B of the first roll 51 and the peak 52A of the second roll 52 mesh with each other. At the position where the valley 51B of the first roll 51 and the peak 52A of the second roll 52 mesh with each other, the space between the first roll 51 and the second roll 52 is narrow, so the second fiber aggregate 42 is compressed. Thus, the fiber density of the recess 222 can be increased.

  On the other hand, when the first fiber assembly 41 passes between the fourth roll 54 and the fifth roll 55, the first fiber assembly 41 has a high density region 412 and a low density region 414 corresponding to the shape of the roll. And the opening part 416 (FIG. 4A and 4B) can be formed. Specifically, since the first fiber assembly 41 is squeezed at a position where the raised portion 54A of the fourth roll 54 is pressed against the fifth roll 55, the fiber density at that location increases, and FIGS. 4A and 4B show A high density region 212 is formed as shown. In addition, an opening 216 is formed in the first fiber assembly 41 at a position where the recess 54 </ b> B of the fourth roll 54 and the protrusion 55 </ b> A of the fifth roll 55 mesh with each other.

  The raised portions 54A and the depressions 54B of the fourth roll 54 have a pattern shape corresponding to the configuration of the high-density regions 212, the low-density regions 214, and the apertures 216 of the first fiber layer 210 as shown in FIGS. 4A and 4B. Is formed.

  The 1st fiber layer 210 and the 2nd fiber layer 220 which were formed as mentioned above are pressed lightly between the 1st roll 51 and the 3rd roll 53, and both are compounded. In this case, the third roll 53 may be heated. Thereby, both the fiber layers 210 and 220 can be combined by thermal fusion of thermoplastic binder particles or binder fibers previously contained in the first fiber layer 210 and / or the second fiber layer 220.

  In addition, when not forming the opening part 216 as shown to FIG. 4A and FIG. 4B, by using the roll in which the hollow 54B of the 4th roll 54 and the protrusion 55A of the 5th roll are used, FIG. The 1st fiber layer 10 which does not have an opening part as shown to FIG. 1B can be formed.

  9 performs the formation of the first fiber layer 210, the formation of the second fiber layer 220, and the composite of the first fiber layer 210 and the second fiber layer 220 in one apparatus. It is also possible to form the fiber layers 210 and 220 with separate apparatuses, and then combine both in another apparatus.

(Absorbent article)
The above-mentioned composite sheet can be suitably used as a surface sheet of an absorbent article. FIG. 10 shows an absorbent article 100 using the above-described composite sheet. The absorbent article 100 includes a main body (absorbent) having a liquid-permeable top sheet (composite sheet) 1, a liquid-impervious back sheet 2, and an absorbent body 4 provided between the two sheets 1 and 2. Article main body) 8. In order to maintain the shape of the absorbent body 4, the absorbent body 4 may be wrapped with an encapsulating sheet 5 made of crepe paper or nonwoven fabric. As shown in FIG. 10, the overall shape is an elongated shape having a predetermined length in the front-rear direction, and has a substantially constant width in a direction orthogonal to the front-rear direction.

  In addition, as the back surface sheet 2 of the absorbent article 100, a sheet material having at least water shielding properties such as an olefin resin sheet such as polyethylene or polypropylene can be used. A laminated nonwoven fabric obtained by laminating a nonwoven fabric on a polyethylene sheet or the like, or a laminated sheet of a nonwoven fabric that is substantially impervious to liquid by interposing a waterproof film can be used. Further, it is more desirable to use a material having moisture permeability from the viewpoint of preventing stuffiness. As such a water-impervious / breathable sheet material, a sheet obtained by melt-kneading an inorganic filler in an olefin resin such as polyethylene or polypropylene to form a sheet and then stretching it in a uniaxial or biaxial direction can be obtained. A porous sheet can be used.

  The absorbent body 4 interposed between the back sheet 2 and the top sheet 1 is not limited as long as it is a material that can absorb and retain body fluid, but preferably contains cotton-like pulp and a water-absorbing polymer. As the water-absorbing polymer, a superabsorbent polymer (SAP), a superabsorbent fiber (SAF), and a combination thereof can be used. Examples of pulp include cellulose fibers such as chemical pulp obtained from wood and dissolved pulp, and artificial cellulose fibers such as rayon and acetate. As raw materials for chemical pulp, hardwood, softwood, etc. are used, but softwood is preferably used because of its long fiber length.

  Further, the absorbent body 4 may be mixed with synthetic fibers. As synthetic fibers, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon, and copolymers thereof can be used. It can also be used. In addition, composite fibers such as a core-sheath fiber, a side-by-side fiber, and 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 addition, it is also possible to use a hydrophobic fiber that has been surface treated with a hydrophilizing agent to impart affinity to body fluids.

  The thickness of the absorber 4 can be in the range of 0.5 to 25 mm, and is preferably in the range of 1.5 to 10 mm. The absorbent body 4 does not have to have a uniform thickness over the front surface, and may have a structure in which the body fluid discharge port corresponding region 30 and the like are bulged. In addition, the absorbent body 4 is preferably manufactured by a stacking fiber or an airlaid method.

  As the side nonwoven fabric 7, a water-repellent treated nonwoven fabric or a hydrophilic treated nonwoven fabric can be used. For example, in order to increase the effect of preventing permeation of menstrual blood or vaginal discharge or the feeling of touch, it is preferable to use a water repellent nonwoven fabric coated with a silicon-based, paraffin-based, alkylchromic chloride-based water repellent or the like . As a kind of the nonwoven fabric, a soft air-through nonwoven fabric which is difficult to crease and hardly wrinkles is preferable. Also, a spunbond / meltblown mixed nonwoven fabric is preferred because of its high strength and resistance to friction.

  The total length of the absorbent article 1 can be 130 to 450 mm, 140 to 360 mm, or 170 to 270 mm.

  The absorbent article 100 of this embodiment may be provided with a compressed groove (also referred to as a compressed groove or emboss) 9. The compressed groove 9 is formed as a groove recessed from the top sheet 1 to the back sheet 2 side. Thereby, the deformation | transformation suitable for the shape of the body can be made easy, and the transfer of the bodily fluid on the surface or inside can be controlled.

1, 201, 301, 401, 501 Composite sheet (surface sheet)
2 Back sheet 4, 404 Absorber 5 Encapsulating sheet 7 Side nonwoven fabric 8 Main body (absorbent article main body)
10, 210, 310, 410, 510 First fiber layer 12, 212, 312, 412, 520 High density region 14, 214, 314, 414, 514 Low density region 216, 316, 416, 516 Opening portion 20, 220 , 320, 420, 520 Second fiber layer 21, 221, 321, 421, 521 Convex part 22, 222, 322, 422, 522 Concave part 41 First fiber aggregate 42 Second fiber aggregate 50 Composite sheet manufacturing apparatus 51 First roll 52 Second roll 53 Third roll 54 Fourth roll 55 Fifth roll 51A First roll 51 peak 51B First roll 51 valley 52A Second roll 52 peak 52B Second roll 52 valley 54A Fourth Bump 54B of roll 54 Depression 55A of fourth roll 54 Protrusion 100 of fifth roll 55 Absorbent article

Claims (8)

A composite sheet comprising a first fiber layer and a second fiber layer disposed under the first fiber layer,
The first fiber layer has a flat plate shape, and has a high density region and a low density region having a fiber density lower than the high density region,
The second fiber layer has a plurality of protrusions protruding toward the first fiber layer, and the top of at least some of the plurality of protrusions is the height of the first fiber layer. A composite sheet in contact with the density region.   The composite sheet according to claim 1, wherein the fiber density of the convex portion is higher than the fiber density of the high-density region.   The composite sheet according to claim 1 or 2, wherein the second fiber layer has a recess between the plurality of protrusions, and the fiber density of the recess is higher than the fiber density of the protrusion.   The top of at least some of the plurality of convex portions is at least partially disposed in the low density region of the first fiber layer in plan view. A composite sheet according to claim 1.   The composite sheet according to claim 4, wherein a top portion of the convex portion disposed at least partially in the low density region is separated from the first fiber layer.   The composite sheet according to any one of claims 1 to 5, wherein the low density region has an aperture.   The composite sheet according to claim 6, wherein at least a part of the plurality of convex portions is formed so as to protrude from the opening portion.   It has the composite sheet as described in any one of Claim 1 to 7 as a surface sheet, a liquid-impermeable back sheet, and the absorber provided between the said surface sheet and the said back sheet. Absorbent article provided with a main body.

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