RU2751905C1 - Absorbent product - Google Patents

Abstract

FIELD: absorbent products.SUBSTANCE: absorbent product 10 is proposed, comprising an upper layer 1, a layer 2 that protects against leakage, and an absorbent layer 3, while the layer 2 that protects against leakage is applied directly to the absorbent layer 3. The layer 2 that protects against leakage contains a layer 41 of meltblown and protective layer 42 for layer 41 meltblown, and the absorbent article 10 has one or more elements selected from items (i) and (ii) below. (i) The anti-leakage layer 2 comprises an embossed portion in which the meltblown layer 41 and the protective layer 42 are bonded, and a non-embossed portion other than the embossed portion. The leakage protection layer 2 comprises an embossed portion in which the meltblown layer 41 and the backing layer 42 are bonded, and a non-embossed portion other than the embossed portion. Layer 2, which protects against leakage, contains a zone without holes in the non-embossed portion. A zone without holes is a zone that does not contain a through hole, in which, in the plan view of the anti-leakage layer 2, the interfiber space containing the zone in which the zone of the rectangle E formed with the length of the diagonals E1 and E2 equal to 10 mcm, reaches 25 mcm2or more, passes through in the thickness direction. The zone without holes is located in the zone in which the anti-leakage layer 2 overlaps the absorbent layer 3. (ii) The protective layer 42 is located on the side of the meltblown layer 41 not facing the absorbent layer. The anti-leakage layer 2 comprises a piled zone in which the number of fibers of the meltblown layer 41, which are fibers that penetrate into the protective layer 42, is 2.5 fibers or more per mm. The average fiber diameter of the fibers of the meltblown layer 41 is 2.5 mcm or less. The piled zone is located in the zone where the anti-leakage layer 2 overlaps the absorbent layer 3EFFECT: absorbent product improvement.7 cl, 6 dwg

Description

TECHNICAL FIELD OF THE INVENTION

{0001}

The present invention relates to an absorbent article such as a sanitary napkin or diaper.

BACKGROUND OF THE INVENTION

{0002}

A nonwoven is often used in an absorbent article such as a sanitary napkin for texture or the like reasons. Various proposals have been made regarding such nonwovens.

For example, Patent Literature 1 discloses a nonwoven fabric including fluffy fibers included with free fibers crisscrossing the fluffy fibers for reasons related to improving the texture of the nonwoven fabric.

Patent Literature 2 discloses an absorbent article having a barrier layer comprising a spunbond web and a meltblown web. For reasons related to obtaining a barrier layer not only with barrier properties, but also with high flexibility and softness for sensitive skin, the number average fiber diameter of each nonwoven web and the total mass fraction of the meltblown nonwoven web are maintained within certain ranges.

LIST OF REFERENCES

PATENT LITERARY SOURCES

{0003}

Patent Literature 1: JP-A-2016-65335 (“JP-A” means Japanese Unexamined Published Patent Application)

Patent Literature 2: JP-T-2011-529749 (“JP-T” means the published Japanese translation of the PCT international application)

SUMMARY OF THE INVENTION

{0004}

In accordance with the present invention, there is provided an absorbent article including a topsheet, a leakage control layer, and an absorbent layer sandwiched between the topsheet and the leakage control layer, the leakage control layer being applied directly to the absorbent layer, and the anti-leakage layer includes a meltblown layer and a protective layer for the meltblown layer.

In an embodiment, the leakage protection layer includes an embossed portion in which the meltblown layer and the backing layer are bonded, and a non-embossed portion other than the embossed portion.

In an embodiment, the leakage control layer includes a no-hole area in the non-embossed portion.

In an embodiment, a zone without holes is a zone that does not include a through hole, in which, in a plan view of the leakage protection layer, an interfiber space containing a zone in which the area of a rectangle formed with a diagonal length of 10 μm is reaches 25 μm ² or more, passes through in the thickness direction.

In an embodiment, the area without holes is located in the area in which the leakage barrier overlaps the absorbent layer.

In an embodiment, the backsheet is located on the side of the meltblown layer not facing the absorbent layer.

In an embodiment, the leakage control layer includes a tufted area in which the number of fibers of the meltblown layer, which are fibers that penetrate into the backing layer, is 2.5 fibers or more per mm.

In an embodiment, the average fiber diameter of the fibers of the meltblown layer is 2.5 µm or less.

In an embodiment, the nailed area is located in the area in which the leakage barrier overlaps the absorbent layer.

{0005}

Other and additional objects, features and advantages of the invention will become more apparent from the description below with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

{0006}

{Fig. 1} FIG. 1 is a cross-sectional drawing showing one embodiment of an absorbent article according to the present invention.

{Fig. 2} FIG. 2 is an explanatory drawing schematically showing a method for confirming a "zone in which the area of a rectangle formed with a diagonal length of 10 μm reaches 25 μm ² or more" for a nonwoven fabric forming a leakage control layer in an absorbent article according to the present invention.

{Fig. 3} FIG. 3 is a partially enlarged cross-sectional drawing schematically showing a preferred embodiment of a nonwoven fabric forming a leakage barrier in an absorbent article according to the present invention.

{Fig. 4} FIG. 4 is a partially enlarged cross-sectional drawing schematically showing another preferred embodiment of a nonwoven fabric forming a leakage barrier in an absorbent article according to the present invention.

{Fig. 5} FIG. 5 is a photograph in lieu of the drawing taken for a section through the nonwoven fabric corresponding to FIG. 4.

{Fig. 6} FIG. 6 is a photograph replacing the drawing taken from the surface side of the nonwoven layer shown in FIG. 5, which does not face the absorbent layer.

DESCRIPTION OF IMPLEMENTATION OPTIONS

{0007}

The present invention relates to an absorbent article including a leakage control layer formed of a nonwoven fabric, in which liquid leakage prevention is improved without adversely affecting softness.

{0008}

Even in the known nonwoven fabrics described in Patent Literatures 1 and 2 above, or in a meltblown nonwoven fabric in which the interfiber spacing is generally small, fine interfiber through holes are formed. When such a nonwoven fabric is used as a leakage layer in an absorbent article, leakage of liquid can be prevented to some extent by the amount of liquid depending on the size of the through holes. However, there is a limit to this amount of liquid.

A possible countermeasure is to close the vias to some extent by reducing the diameter of the fibers or increasing the basis weight of the nonwoven to thereby fill the interconnecting spaces between the fibers. However, since this method increases the amount of fibers, it can lead to an increase in the hardness of the nonwoven fabric and adversely affect the feel of it, and therefore does not provide an effective solution for obtaining a leakage protection layer in an absorbent article in contact with skin.

In the calendering used in the prior art nonwoven fabrication method, the openings between the fibers can be filled to some extent when the fibers are compressed. However, in areas free from fibers, it is difficult to completely fill the through holes, which cause fluid leakage. If one resorts to increasing the degree of thermocompression bonding by means of calendering (increasing the force during thermocompression bonding or increasing the area of the thermocompression bonding zone), the curing of the nonwoven material increases due to flattening of the fibers and, accordingly, the softness is lost.

{0009}

On the other hand, the absorbent article according to the present invention includes a leakage prevention layer formed of a nonwoven fabric in which liquid leakage prevention is improved without adversely affecting softness.

{0010}

An absorbent article according to the present invention will be explained below based on a preferred embodiment with reference to the drawings. The nonwoven fabric of the present invention can be applied to a variety of fabrics that absorb and retain discharged fluid. For example, the nonwoven fabric can be used in a diaper, sanitary napkin, panty liner, incontinence pad, and urological pad.

{0011}

In the present invention, unless otherwise specified, the side that comes into contact with the human body is referred to as the skin-facing surface side, the skin-contacting surface side or the upper surface side, and the side that is opposite to the above-mentioned side is referred to as the side of the surface not facing the skin, the side of the surface not in contact with the skin, or the side of the rear surface. In particular, the side of the skin-contacting surface and the side of the non-skin-contacting surface in the leak-proof layer are referred to in some cases as the side facing the absorbent layer and the side not facing the absorbent layer. The direction normal to the top surface or back surface of the absorbent article is referred to as the thickness direction, and the dimension in this direction is referred to as the thickness.

{0012}

FIG. 1 shows a cross-section of an absorbent article 10 according to an embodiment. The absorbent article 10 includes a liquid-permeable topsheet 1 located on the skin-contacting surface side, a leak-proof layer 2 located on the non-skin contacting surface side, and a liquid retaining absorbent layer 3 located between top layer 1 and layer 2 to prevent leakage. The absorbent layer 3 is a layer of hydrophilic material located on the side of the surface of the topsheet 1 that is not in contact with the skin and may contain not only an accumulation (absorbent core) of liquid absorbents such as cellulose and absorbent polymer, but also a cover sheet (also referred to like a sheet for wrapping the core), which covers the accumulation of liquid absorbers. Specific examples of the cover sheet include liquid-permeable, fibrous sheet such as tissue paper (tissue paper) and nonwoven fabric.

{0013}

The leakage protection layer 2 is applied directly to the absorbent layer 3. That is, the leakage protection layer 2 and the absorbent layer 3 are superimposed on each other with no other layers between these two layers except for the agent (adhesive or the like) used for bonding. In the absorbent article 10 of the embodiment, the leakage barrier layer 2 forms a layer closest to the side of the surface of the absorbent article 10 that is not in contact with the skin. However, in an absorbent article according to the present invention, the leakage barrier does not have to be the layer closest to the side of the surface that is not in contact with the skin. For example, when the absorbent article of the present invention is a sanitary napkin or the like, an adhesive for attaching the article to a garment provided on the side of that surface of the leakage protection layer that does not face the skin, a release paper for covering the adhesive may be placed, while the adhesive is not being used, or the like. The absorbent article 10 of the embodiment preferably does not include any film on the side of the surface of the absorbent layer 3 not in contact with the skin. The anti-leakage layer 2 preferably has a surface 21 on the side 2A facing the absorbent layer that is in contact with the absorbent layer 3 and a surface 22 on the side 2B not facing the absorbent layer. The surface 22 on that side 2B of the leakage protection layer 2 that does not face the absorbent layer preferably forms the outer surface of the absorbent article 10.

{0014}

The leakage-proof layer 2 includes a fibrous layer 4 such as a nonwoven fabric or the like as a component. In particular, as shown in FIG. 3, the anti-leakage layer 2 has a fibrous layer 4 including a meltblown layer 41 and a protective layer 42 for the meltblown layer 41. The backsheet 42 is preferably located on at least the side of the meltblown layer 41 not facing the absorbent layer. The backing layer 42 is a layer that enhances the strength or the like of the meltblown layer 41. The anti-leakage layer 2 preferably includes an embossed portion (not shown) in which the meltblown layer 41 and the backing layer 42 are bonded, and a non-embossed portion (not shown) other than the embossed portion. The embossed portion herein means the area in which the constituent fibers of the fibrous layer 4 are densified and hot-stamped together. In the embossed portion formed in the fibrous layer 4 by this sealing and bonding, its thickness is reduced in comparison with other places in the fibrous layer 4. The embossed portion has, for example, a circular or rectangular shape, and the embossed portions can be formed dispersed over the entire area of the fibrous layer. 4. Alternatively, a plurality of lines can also be formed from straight or curved embossed portions. A plurality of lines from rectilinear or curved embossed portions can also be formed so that lines from a given plurality can intersect with each other.

{0015}

The leakage layer 2 includes synthetic fibers as constituent fibers and is preferably water repellent. Thereby, the leakage protection layer 2 has the function of preventing the leakage of the discharged liquid that has passed from the topsheet 1 and is absorbed in the absorbent layer 3 outward from the absorbent article 10. Thus, the leakage protection layer 2 including the fibrous layer 4 preferably includes the following fiber structure as a component in a region in which the leakage protection layer 2 overlaps the absorbent layer 3.

{0016}

Namely, the leakage-proof layer 2 preferably includes, in the region in which the leakage-proof layer 2 overlaps the absorbent layer 3, a region without holes in the non-embossed portion. A region without holes is a region that does not include a "through hole in which, in a plan view, an interfiber space containing a region in which the area of a rectangle formed with a diagonal length of 10 μm reaches 25 μm ² or more passes through in the thickness direction "(hereinafter referred to as" through hole "). The size of the "area in which the area of the rectangle formed with a diagonal length of 10 μm reaches 25 μm ² or more" is the size at which there is concern about water seepage from the leakage protection layer in the following state - a namely, in a state in which the discharged liquid in the absorbent article enters the leakproof layer from the topsheet and the pressure due to the sitting position will be applied to the water (liquid such as the discharged liquid that is absorbed by the absorbent article). The through hole is a hole that extends through in the thickness direction with a predetermined dimension as defined above, and the presence of a “no-hole zone” that does not include the through hole can be confirmed either from the side of surface 21 on that side 2A of the layer 2, preventing leakage, which faces the absorbent layer, or from the side of surface 22 on its side 2B, not facing the absorbent layer.

{0017}

"Plan view" herein means a top view of the surface (surface 21 on side 2A facing the absorbent layer or surface 22 on side 2B not facing the absorbent layer) of the sheet that forms the leakage barrier layer 2. "An opening that extends through in the thickness direction" herein means an opening in which "in a plan view, an interfiber space in which the area of a rectangle formed with a diagonal length of 10 μm reaches 25 μm ² or more" in the direction of the thickness of the layer 2, which protects against leakage, in the presence of a given area.

In addition, the diagonal length and area requirements described above as defined for the "through hole" herein mean leakage when seated pressure is applied to water corresponding to the discharged liquid to be absorbed into the absorbent product.

{0018}

(Through hole measurement method)

The presence or absence of a through hole can be determined by the following method.

That is, the surface (surface 21 on the side 2A facing the absorbent layer or surface 22 on the side 2B not facing the absorbent layer) of the sheet constituting the leakage proof layer 2 is examined at a magnification of 3000 times using a scanning electron microscope ( SEM) (manufactured by JEOL Co., Ltd., JCM-6000PLUS (trade name), which, for example, is the same elsewhere in this description) to identify interfiber spaces that go through without being covered by fibers if look from the front inward (in the direction of the thickness of the anti-leakage layer 2) on the observation screen (or image capturing screen). Investigate whether a rectangle (including a square) can be drawn that corresponds to a given interfiber space and in which two straight lines with a size of 10 μm intersect at the midpoint or not. Meanwhile, when the area of the rectangle is 25 µm ² or more, it is concluded that there is a through hole.

The area of the rectangle is calculated based on the following Formula [1]. The lesser of the angles at the midpoint at which straight lines intersect in the rectangle mentioned above is taken as the intersection angle θ (0 ° θ 90 °) to measure the intersection angle θ. The area of the rectangle in which the intersection angle θ is formed with a value of 30 ° or more with a diagonal length of 10 µm reaches 25 µm ² or more.

Rectangle area = (1/2) × (Diagonal length: 10 μm) ² × sin θ [1]

When the leakage protection layer is separated from the commercially available absorbent article for the measurement described above, the hot melt adhesive that adheres the materials together is cured by spraying a cooling spray 10 cm from the outermost side for about 5 seconds, and then the leakage layer is carefully peeled off. The method of separating / extracting the leakage layer is used for other measurement methods in this description.

{0019}

The through hole measurement method described above may be performed, for example, as shown in FIG. 2. That is, when the leakage protection layer 2 is viewed from the side of the surface 21 on the side 2A facing the absorbent layer or from the side of the surface 22 on the side 2B not facing the absorbent layer, a space 49 is revealed that is surrounded by fibers 48 and does not overlap with other fibers in the thickness direction. After that, depending on whether a rectangle E can be drawn, in which two straight lines E1 and E1 (which are drawn with a size of 10 microns and intersect at the midpoint and the angle of intersection between which is "adjusted" so that it is θ = 30 ° or more and 90 ° or less) are used as diagonals or not, it is judged whether or not there is a through hole as defined above. When rectangle E can be drawn, it is concluded that the monitored leakage layer includes a through hole. When the rectangle E cannot be drawn, it is concluded that the monitored leakage layer does not include a through hole.

{0020}

The case in which the leakage protection sheet 2 does not include the through hole defined above includes, for example, the aspect described below. That is, even if an interfiber space that satisfies the diagonal line and area requirements described above is present on the top surface in a plan view, when there are fibers that overlap the interfiber space in its depth and the "hole" does not penetrate the direction of the thickness, while maintaining the size described above, the leakage layer 2 does not include the through hole described above. In addition, when a hole so small that a rectangle having a diagonal with a length of 10 μm cannot be drawn is present in the interfiber space, which is visible on the front side when viewed from the through hole in a plan view, the leakage barrier layer 2 is also does not include the through hole described above. In the same way, also when there is a small hole in which the area of a rectangle drawn so that two straight lines with a size of 10 μm can intersect at the midpoint does not reach 25 μm ² or more (namely, is less than 25 μm ² ), the leakage layer 2 also does not include the through-hole described above.

{0021}

Specific examples of the method for producing the leakage proof layer 2 that has a hole-free zone having no through hole as defined above include various methods such as a method for increasing the number of fibers by increasing the basis weight.

First of all, for reasons of maintaining softness without excessively increasing the number of fibers to improve liquid leakage prevention, the leakage barrier layer 2 preferably includes the structure shown below.

{0022}

That is, when considering the leakage protection layer 2, it should be noted that in the multilayer structure consisting of the meltblown layer 41 and the protective layer 42 mentioned above, the leakage protection layer 2 preferably includes a tufted area 6 in which the number of fibers of the meltblown layer 41, which are fibers that penetrate the backing layer 42, is 2.5 fibers or more per 1 mm in the area that overlaps the absorbent layer 3 (see the partially enlarged drawing corresponding to the circle denoted by the reference number P in Fig. 3).

{0023}

"Tufted area 6" as used herein means the fibrous structure within the anti-leakage layer 2 as described above. That is, the portion inside the leakage layer 2 including a structure in which a portion of the fibers (for example, one end of the fiber) protrudes from the fiber cluster 41B forming the meltblown layer 41 and the protruding fibers (fluffed fibers) 41A penetrate into the space between the fibers 42A of the backing layer 42, referred to as the "tufted area 6". The backing layer 42, into which the fibers of the meltblown layer 41 penetrate, is preferably located on the side 2B of the meltblown layer 41 not facing the absorbent layer.

{0024}

The multilayer structure of the leakage layer 2 is not limited to the embodiment of the two-layer structure shown in FIG. 3, and provided that the multilayer structure includes a backing layer 42 located at least on the side 2B not facing the absorbent layer, the multilayer structure may encompass a structure having three or more layers. For example, as shown in FIG. 4, the multilayer structure can also be a structure having another backing layer 43 located on the side 2A facing the absorbent layer, in addition to the backing layer 42 located on the side 2B of the meltblown layer 41 not facing the absorbent layer. Alternatively, although not shown, the meltblown layer 41 may be formed in two or more layers, or each of the protective layers 42 and 43 may be formed in two or more layers. However, for reasons of maintaining the softness of the leakage layer 2, the leakage layer 2 preferably has a "tufted region 6, in which the number of fibers of the meltblown layer 41, which are fibers that penetrate into the backing layer 42, is 2. , 5 fibers or more per 1 mm ", and which is described above, with as few layers as possible superimposed on each other (see partially enlarged drawing in a circle denoted by the reference number P in Figs. 3 and 4).

{0025}

The tufted area 6 mentioned above is present within the anti-leakage layer 2, whereby a portion of the fibers of the meltblown layer 41 rises and is positioned so that the fibers can pass into the interfiber space of the anti-leakage layer 2 even without excessively increasing the number of fibers layer 2, which protects against leakage. As a result, the through hole is filled in the thickness direction, and the leakage proof layer 2 has a high liquid leakage prevention ability without negatively affecting the softness.

{0026}

For reasons related to preventing liquid leakage, making the number of fibers that penetrate inward in the pile area 6 of the anti-leakage layer 2 to 2.5 fibers or more per mm means providing the number of fibers that fill the through hole mentioned above.

{0027}

For reasons related to preventing liquid leakage, the number of fibers that penetrate from the meltblown layer 41 into the backing layer 42 in the pile area 6 is preferably 5 fibers or more per 1 mm, and more preferably 10 fibers or more per 1 mm. For reasons related to air permeability, the number of fibers that penetrate as described above is preferably 100 fibers or less per 1 mm, more preferably 50 fibers or less per 1 mm, and even more preferably 40 fibers or less per 1 mm. In particular, the number of fibers that penetrate from the meltblown layer 41 into the backing layer 42 in the pile area 6 is preferably 2.5 fibers or more per 1 mm and 100 fibers or less per 1 mm, more preferably 5 fibers or more per 1 mm. and 50 fibers or less per 1 mm, and even more preferably 10 fibers or more per 1 mm and 40 fibers or less per 1 mm.

{0028}

(Method for determining the number of fibers in the meltblown layer that penetrate the protective layer)

The number of fibers of the meltblown layer 41 that penetrate the backing layer 42 can be determined by the method described below.

When separating the leakage control layer from a commercially available absorbent article, the leakage control layer 2 in the area that overlaps the absorbent layer is separated according to the method shown in (Through Hole Measurement Method) above. The separated leakage layer 2 is cut in the thickness direction to obtain a cross-section. Layer 2, protecting against leakage, is placed on the stage for observation so that the section can be turned upward for viewing the surface obtained by cutting, at a magnification of 100 times using the SEM.

As for the length (length in the plane direction in the cross-section of the layer that protects against leakage) of the field of view, the size of the field of view in one place when examining the layer that protects against leakage by means of SEM is adjusted to 1 mm to determine the number of fibers in ten places. The number of tufted fibers 41A that penetrate from the meltblown layer 41 into the backing layer 42 located on the side 2B not facing the absorbent layer is counted at each location. The sum of the numbers counted in the ten places described above is taken as the numerator to calculate the number based on the following Formula [2].

(The number of fibers in the meltblown layer, which are fibers that penetrate the backing layer 42)

= (the number of fibers of the meltblown layer 41, which are fibers that penetrate the protective layer 42, in the field of view when observed) (fibers)

/ L (the length of the contact surface of the protective layer 42 and the meltblown layer 41 in the field of view during observation (10 mm)) [2]

{0029}

Specific examples of the cut surface to be viewed in the thickness direction include the SEM image shown in FIG. 5. In the cross section of the leakage layer 2 shown in FIG. 5, a three-layer structure is formed of a backing layer (spunbond layer) 43 located on the side 2A facing the absorbent layer, a meltblown layer 41 and a backing layer (spunbond layer) 42 located on the side 2B not facing the absorbent layer. In the SEM image in FIG. 5, the piled fibers 41A protruding from the fiber accumulation 41B forming the meltblown layer 41 penetrate the space between the fibers 42A of the backsheet 42 located on the side 2B not facing the absorbent layer.

The fibers of the meltblown layer 41, which are fibers that penetrate the backing layer 42, are preferably formed as shown in the SEM image shown in FIG. 6, for example when viewed from the side of surface 22 on the side 2B not facing the absorbent layer. That is, as shown in the rectangular area bounded by the dash-dot line in the SEM image of FIG. 6, the tufted fibers 41A of the meltblown layer 41 are preferably brought into a state in which the tufted fibers 41A are entangled with the fibers 42A of the backing layer 42 when the brushed fibers 41A penetrate the space between the fibers 42A of the backing layer 42. Thereby, the state in which the tufted the fibers 41A of the meltblown layer 41 penetrate the backing layer 42.

{0030}

FIG. 5, protective layers 42 and 43 are located on both surfaces of the meltblown layer 41 as shown in FIG. 4. In this case, as shown in FIG. 5, the tufted area 6 is preferably located on the side 2B not facing the absorbent layer. This is due to the fact that, for reasons related to preventing liquid leakage, the state of the piled fibers is maintained. More specifically, this is due to the fact that the fibrous structure of the pile area 6 is protected from the pressure of the liquid that flows from the absorbent layer 3 to prevent the formation of a through hole when using the absorbent article. The tufted area 6 can be located both on the side 2B, not facing the absorbent layer, and on the side 2A, facing the absorbent layer.

{0031}

For reasons related to preventing liquid leakage, the fleece area 6 is preferably located in the entire area in which the leakage protection layer 2 overlaps the absorbent layer 3. More preferably, the fleece area 6 extends from the area that overlaps the absorbent layer 3 to a flat area that does not overlap the absorbent layer 3 outside of this area, which overlaps the absorbent layer.

{0032}

In the leakage layer 2, the fibers of the meltblown layer 41 are preferably not exposed to the top surface (the top surface being surface 22) on the side 2B not facing the absorbent layer. As a means by which the fibers of the meltblown layer 41 are not exposed to the surface, the thickness of the backsheet 42 located on the side 2B not facing the absorbent layer with respect to the meltblown layer 41 can be adjusted to a predetermined level, or the fibers can also be fixed by using, for example, a hot melt adhesive or the like.

Thus, the fibers of the meltblown layer 41 are not exposed to the upper surface (the upper surface being surface 22) on the side 2B not facing the absorbent layer, and therefore the fluffed fibers of the meltblown layer 41 are protected, the fibrous structure of the flecked area 6 is preserved, and it will be difficult for liquid to seep out of the leakage layer 2.

(A method of confirming whether the fibers of the meltblown layer are exposed to the top surface of the anti-leakage layer or not)

The presence or absence of fibers exposed to exposure, as described above, can be confirmed by inspecting the upper surface of the observed object at a magnification of 100 times using SEM.

When the fibers of the meltblown layer 41 are displayed on the uppermost surface of the observation screen, it is concluded that the fibers of the meltblown layer are exposed to the upper surface. If this is not the case, for example, when only the fibers of the cover are displayed on the uppermost surface of the observation screen, it is concluded that the fibers are not exposed to attack on that surface.

{0033}

A “meltblown layer” as used herein means a layer of fibers (a layer of nonwoven fabric of the type that is directly bonded during spinning) formed by spinning fibers from a heated and melted thermoplastic resin and allowing the resulting fibers to accumulate on conveyor, whereby the fibers are converted into nonwoven fabric in accordance with the so-called meltblown process. In the blown melting process, molten resin exiting the orifices of a die is blown by a high temperature gas jet stream to form flock fibers having an ultra-small size by breaking. Therefore, the obtained meltblown layer is a nonwoven fabric layer formed from ultrafine fibers having a fiber diameter of 10 µm or less. The constituent fibers are formed from filaments having a fiber length of 30 µm or more. The fiber-to-fiber distance is also small. Such a meltblown layer 41 provides a very good touch feel and has very good barrier properties. On the other hand, reinforcement with the protective layer 42 is required to provide strength or wear resistance.

{0034}

For reasons of very good liquid leakage prevention, the average diameter (R1) of the fibers constituting the fibers of the meltblown layer 41 is preferably 2.5 μm or less, more preferably 1.5 μm or less, and even more preferably 1 μm or less. ... The average diameter (R1) of the fibers is in practice 0.1 µm or more. In particular, the average diameter (R1) of the fibers constituting the fibers of the meltblown layer 41 is preferably 0.1 µm or more and 2.5 µm or less, more preferably 0.1 µm or more and 1.5 µm or less and still more preferably 0.1 µm or more and 1 µm or less. In the multilayer structure of the leakage layer 2, which consists of the meltblown layer 41 and the protective layer 42, the average diameter (R1) of the fibers constituting the fibers of the meltblown layer 41 is limited to the limits described above, and therefore the interfiber space can be further narrowed for more reliably preventing the situation in which the leakage protection layer 2 includes the through-hole mentioned above.

{0035}

The protective layer 42 is a layer of fibers that enhances the strength or the like of the meltblown layer 41, and is preferably formed by using fibers having a larger fiber diameter than the fiber diameter of the meltblown layer 41. As the protective layer 41, various fibrous layers can be used, provided that this layer can increase the strength or the like of the meltblown layer 41. The protective layer 42 is preferably formed from a spunbond layer from these layers for cost reasons.

{0036}

"Spunbond layer" in this document means a layer of nonwoven fabric that is obtained by a so-called spunbond method. As with the meltblown layer, the spunbond layer is a fibrous layer formed by spinning a heated and melted thermoplastic resin into fibers and allowing the resulting fibers to accumulate on a conveyor. However, in the spinneretting process, fibers are formed by cooling and drawing the molten resin exiting the orifices of the spinneret. The resulting spunbond layer has a larger fiber diameter than the fiber diameter of the meltblown layer and is a fibrous layer formed from fibers having a longer fiber length (continuous fibers). Preferably, a spunbond layer is applied to the meltblown layer, and thereafter, hot embossing is applied to these layers, and the resulting product is converted into a nonwoven fabric in which both layers are bonded together.

{0037}

For reasons related to more reliably preventing the situation in which the leakage protection layer 2 includes the through-hole mentioned above, for reasons related to the further increase in the number of fibers of the meltblown layer 41, which are fibers that penetrate the protective layer 42 in the nailed area 6, and for reasons related to further increasing the effectiveness of the protective layer 42, which performs the function of protection in relation to the meltblown layer 41, the average diameter (R1) of the fibers, which are fibers of the meltblown layer 41, is preferably less than the average diameter (R2) fibers constituting the fibers of the guard layer 42. For these reasons, the ratio (R1 / R2) of the average diameter (R1) of the fibers constituting the fibers of the meltblown layer to the average diameter (R2) of the fibers constituting the fibers of the guard layer 42 is preferably 1 / 8 or less, more preferably 1/20 or less, and even more preferably 1/25 or less. For reasons related to air permeability, the ratio (R1 / R2) is preferably 1/100 or more, more preferably 1/50 or more, and even more preferably 1/40 or more. In particular, the ratio (R1 / R2) is preferably 1/100 or more and 1/8 or less, more preferably 1/50 or more and 1/20 or less, and even more preferably 1/40 or more and 1/25 or less.

{0038}

(Method for determining the average fiber diameter)

Reference should be made to a method in which five samples, which are small pieces, are taken randomly from the meltblown layer provided in the leakage protection layer, a photograph in which the object of observation is magnified, for example, 1000-10,000 times, is taken like this so that 20-60 fibers can be in the field of view, using an SEM, measure the fiber diameter for all fibers in the field of view so that the fiber can be counted once for each diameter measurement, and the average of the measured values is rounded to the first decimal place for calculating and determining the average fiber diameter.

{0039}

In the meltblown layer 41, for reasons related to maintaining softness when filling the through holes of the leakage layer 2, the filling degree is adjusted to preferably 25% or less, more preferably 20% or less, even more preferably 10% or less, and particularly preferably 5 % or less. "Degree of filling" in this document means the relative content of fibers in a space. The fill rate of the meltblown layer 41 is limited to the range described above. However, if we consider the texture of the meltblown layer 41 itself, it should be noted that this layer may have flexibility, which can provide a smooth curved surface or fold, like in a fabric (high drape) to suppress hardness, similar to the hardness / stiffness of paper or film (crunchy feel: hardness / stiffness, which requires a certain amount of force when bending or the like, and bends easily and does not bend when twisted, for example: dry rubbing sound occurs when touched or twisted or the like).

For reasons related to preventing leakage, the fill rate of the meltblown layer 41 is preferably 2% or more, more preferably 2.5% or more, and even more preferably 3% or more. In particular, the degree of filling of the meltblown layer 41 is preferably 2% or more and 25% or less, more preferably 2% or more and 20% or less, even more preferably 2.5% or more and 10% or less, and particularly preferably 3 % or more and 5% or less.

{0040}

(Method for determining the degree of filling of the meltblown layer)

The degree of filling of the meltblown layer can be determined by the method described below.

The mass of the leakage layer that is the object of measurement is measured. A section of the leakage layer, which is made in the direction of thickness, is observed using the SEM described above and the thickness of the meltblown layer is measured. The meltblown layer is separated on the basis of (Method for determining the surface density of the meltblown layer) described later. The areal density is calculated and the fill rate is calculated by the expression: {areal density of the meltblown layer / (thickness of the meltblown layer x resin density)} × 100.

The "resin density" described above can be determined by the method described below.

That is, the separated meltblown layer is compressed at 180 ° C by means of a LABO PRESS equipment (manufactured by Toyo Seiki Seisaku-Sho, Ltd., model P2-30) and for 1 minute by means of a two-stage compression press (low pressure: 5 kg / cm ³ , high pressure: 150 kg / cm ³ ) and then for 1 minute by means of a press with cooled plates to obtain a film. Thereafter, a piece with dimensions of 10 × 10 cm is cut from the film from a place in which no air is entrained, the mass is measured, and then the resulting value is divided by volume to obtain the density of the resin.

{0041}

For reasons of softness, the basis weight of the meltblown layer 41 is preferably 20 g / m ² or less, more preferably 15 g / m ² or less, and even more preferably 10 g / m ² or less. For reasons related to sheet strength, the basis weight of the meltblown layer 41 is preferably 3 g / m ² or more, more preferably 4 g / m ² or more, and even more preferably 5 g / m ² or more. In particular, the basis weight of the meltblown layer 41 is preferably 3 g / m ² or more and 20 g / m ² or less, more preferably 4 g / m ² or more and 15 g / m ² or less, and even more preferably 5 g / m 2 or less. m ² or more and 10 g / m ² or less.

{0042}

(Method for determining the surface density of the meltblown layer)

The areal density of the meltblown layer can be determined as described below.

The mass of the leakage layer which is the object of measurement is measured dry. A cross-section of the leakage protection layer, which is made in the direction of thickness, is examined using the SEM described above, and the thickness of each of the meltblown layer and the backing layer is measured, and the ratio of their thicknesses is determined. Use the following means to separate the meltblown layer from the leakage protection layer. When the meltblown layer and the backing layer are bonded with a hot melt adhesive or the like, the meltblown layer is carefully peeled off using a cold spray. The mass of the meltblown layer is measured and the resulting value is divided by the area of the sheet forming the leakage layer to calculate the areal density of the meltblown layer. When the meltblown layer and the backing layer are thermally bonded by embossing or the like, the embossed portion is removed, and then the meltblown layer is carefully peeled off by hand, using tweezers or the like. Thereafter, the mass of the meltblown layer is measured, and the resulting value is divided by the value obtained by subtracting the area of the embossed portion from the area of the sheet forming the leakage barrier to calculate the areal density of the meltblown layer.

{0043}

A preferred method of manufacturing the nonwoven fabric serving as the leakage protection layer 2 in the embodiment will be described. In this document, a case will be described where the protective layer 42 is applied as a spunbond layer.

To obtain the meltblown layer 41, the superfine fibers are accumulated on a conveyor belt by the meltblown / meltblown method to continuously move the starting material for the meltblown layer in the machine direction. In this case, the requirements for fiber diameter, degree of filling and areal density indicated above can be satisfied by setting various parameters / modes, such as the diameter of the die hole, air velocity and temperature of the high-temperature gas jet stream. Thereafter, to form the backing layer 42, the spunbond raw material is laminated onto the surface of the meltblown parent material described above by a spunbond method. In this case, the teasing is preferably applied to the surface of the base material for the meltblown layer in the course of the application of the starting material for the spinneret layer thereon. Thereby, the spunbond raw material will be applied to the tufted surface of the meltblown layer raw material, and the tufted region 6 mentioned above will be formed.

{0044}

The tufting can be performed by various methods commonly used as a method for making a nonwoven fabric. For example, the teasing is performed by rotating a convex roller having a plurality of convex portions on the peripheral surface when the convex roller is brought into contact with the surface of the starting material for the meltblown layer. Thereby, piled fibers can be formed.

{0045}

After the teasing, the fibers that have been tapped, cooled and spun-drawn and serve as the starting material for the spunbond layer are allowed to accumulate on the nailed surface of the starting material for the meltblown layer. In this case, the nailed fibers of the meltblown starting material penetrate into the spaces between the fibers of the spunbond starting material, and a nailed region 6 is formed in the leakage-proof layer 2 of the embodiment. Thereby, a nonwoven fabric serving as the leakage layer 2 in the embodiment can be obtained.

{0046}

In this manufacturing method, a structure in which “the number of fibers of the meltblown layer, which are fibers that penetrate into the backing layer, is 2.5 fibers or more per 1 mm” in the pile area 6, can be formed by protruding a part of the fibers (for example , one end of the fiber) from the accumulation of fibers 41B forming the meltblown layer 41, and the penetration of the protruding fibers (piled fibers) 41A into the spaces between the fibers 42A of the backing layer 42 located on the side 2B not facing the absorbent layer. In the method for manufacturing the nonwoven fabric serving as the leakage layer 2, according to the embodiment, a predetermined average fiber diameter, filling ratio, basis weight, or the like can be obtained by appropriately setting different processing modes.

{0047}

In the manufacturing method described above, the backing layer 43 formed from the spunbond layer may be further disposed on the surface serving as the absorbent layer facing side 2A of the starting material for the meltblown layer. In this case, the step of obtaining the starting material for the spinneret layer in the same manner as described above may be further provided downstream of the step for producing the starting material for the meltblown layer. In this case, the meltblown layer starting material is formed on the spinneret starting material obtained in the previous step.

In the method for manufacturing an absorbent article according to the present invention, it is preferable that the nonwoven fabric obtained by the manufacturing method described above is applied directly to the absorbent layer as a leakage barrier. The topsheet is applied to the absorbent layer and the spillage layer (nonwoven fabric), which are superimposed directly on top of each other from the skin-contacting surface of the absorbent layer, and the resulting article is joined together to form an absorbent article of the present invention. ... In some case, the method, if necessary, may include the step of attaching other elements.

{0048}

The constituent fibers of the meltblown layer 41 provided in the leakage-proof layer 2 and the constituent fibers in the case where the protective layers 42 and 43 are formed from spunbond layers are formed of a thermoplastic resin. Specific examples of thermoplastic resins include one or more of a polyolefin resin, a polyester resin, a polyamide resin, an acrylonitrile resin, a vinyl resin, and a vinylidene resin. Specific examples of the polyolefin-based resin include one or more resins selected from polyethylene, polypropylene, and polybutene. Specific examples of the polyester resin include one or more resins selected from polyethylene terephthalate and polybutylene terephthalate. Specific examples of the polyamide-based resin include one or more resins selected from nylon and the like. Specific examples of the vinyl-based resin include polyvinyl chloride and the like. Specific examples of the vinylidene-based resin include polyvinylidene chloride. You can also use a modified product or a mixture of different resins described above.

EXAMPLES

{0049}

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

{0050}

(Example 1)

A spunbond raw material having an average fiber diameter of 20 µm and an areal density of 9 g / m ² is formed by using a polyolefin resin and a spunbond method.

On it, a starting material for a meltblown layer having a basis weight of 10 g / m ² is formed by using a polyolefin resin and a meltblown process (molding temperature: 270 ° C). Teasing was performed over the entire surface of the starting material for the meltblown layer. Specifically, the meltblown feedstock was rubbed once at a speed of 1.2 m / min in the machine direction of the meltblown feedstock while applying a pressure of 165 Pa thereto by means of Sheet Paper manufactured by TRUSCO NAKAYAMA CORPORATION, catalog number: GBS -600-5P. The average fiber diameter, thickness and filling of the resulting meltblown layer were determined based on the (Method for determining the average fiber diameter), (Method for determining the degree of filling of the meltblown layer) and (Method for determining the surface density of the meltblown layer) described above.

Thereafter, a spunbond stock having an average fiber diameter of 20 µm and an areal density of 9 g / m ² was formed on the brushed surface of the meltblown base material by using a polyolefin resin and a spunbond method.

Thereafter, hot embossing was applied to the SMS multilayer fibrous layer (spunbond (S) - meltblown (M) - spunbond (S)), and the resulting article was treated as an SMS nonwoven.

Thereby, a sample of the leakage protection layer was obtained in Example 1, in which the die layers located on both surfaces of the meltblown layer 41 were used as the protective layers 42 and 43.

In the obtained sample of the leakage protection layer, on the surface of the spinneret layer located on the teamed side of the meltblown layer 41, the number of fibers of the meltblown layer 41, which are fibers that have penetrated into the protection layer from the teamed surface of the meltblown layer 41, was determined based on (Method for determining the number of fibers that penetrated the backing layer) indicated above, and this number was shown in Table 1 (hereinafter the same applies to Examples 2 and 3).

Similarly, in the obtained sample of the leakage layer with the spinneret surface located on the side of the meltblown layer 41 exposed to the nap, it was determined whether or not the fibers of the meltblown layer on the upper surface of the spinneret were exposed to exposure, based on (Method of Confirmation, whether the fibers of the meltblown layer on the upper surface of the leakage layer are exposed or not), which is indicated above, and the obtained data were shown in Table 1 (hereinafter the same applies to Examples 2 and 3).

{0051}

(Example 2)

A sample of the leakage layer in Example 2 was prepared in the same manner as in Example 1, except that a meltblown layer 41 was used as shown in Table 1. The fiber diameter shown above was obtained by varying the spinning temperature the meltblown layer in Example 1 to a low temperature (255 ° C).

{0052}

(Example 3)

A sample of the leakage layer in Example 3 was prepared in the same manner as in Example 1, except that a meltblown layer 41 was used as shown in Table 1. The fiber diameter described above was obtained by varying the spinning temperature the meltblown layer in Example 1 to 265 ° C.

{0053}

(Comparative example 1)

A sample of the anti-leakage layer in Comparative example 1 was prepared in the same way as in Example 1, except that the meltblown layer 41 shown in Table 1 was used, for which no teasing was performed. The presence of fibers that did not significantly penetrate the backing layer, regardless of the absence of lint, was due to the pressure applied to the sample during lamination.

{0054}

(Comparative example 2)

A sample of the anti-leakage layer in Comparative Example 2 was prepared in the same manner as in Example 2, except that the meltblown layer 41 shown in Table 1 was used, for which no teasing was performed.

{0055}

(Comparative example 3)

A sample of the leakage layer in Comparative Example 3 was prepared in the same manner as in Example 1, except that a meltblown layer 41 was used as shown in Table 1. The fiber diameter was obtained by varying the spinning temperature of the fibers of the meltblown layer in Example 1 to a low temperature (250 ° C).

(Comparative example 4)

A sample of the leakage protection layer in Comparative Example 4 was prepared in the same manner as in Example 3, except that the meltblown layer 41 shown in Table 1 was used, in which the filling ratio was increased by calendering without subjecting this layer to fluff.

{0056}

(Comparative example 5)

A spunbond raw material and a meltblown layer starting material, which were the same as in Example 2, were prepared one for each layer, and in the state in which both raw materials were superimposed on each other, the water flow in the form of jets were fed twice at different water pressures from each other from the side of the starting material for the meltblown layer. The first jetting was performed at low pressure (2.5 MPa) using nozzles having a diameter of 0.12 mm to entangle the constituent fibers of the spinneret starting material and the meltblown starting material, while both layers were wetted with water and bonded well. ... The second jetting was performed at high pressure (5 MPa) using nozzles having a diameter of 0.1 mm to further entangle the constituent fibers of the spinneret starting material and the meltblown starting material to obtain an SM nonwoven formed of two layers - die layer (S) and meltblown layer (M).

Thereby, a sample of the leakage proof layer was prepared in Comparative Example 5, in which a spinneret layer disposed on one surface of the meltblown layer 41 was used as the protective layer 42. The thickness and filling degree of the meltblown layer were determined based on (Method for determining the degree of filling meltblown layer) and (Method for determining the surface density of the meltblown layer) specified above.

In the sample of the leakage protection layer in Comparative Example 5, the number of fibers of the meltblown layer 41, which are the fibers that penetrated into the protection layer 42 from the surface of the meltblown layer 41, was determined based on (Method for determining the number of fibers that penetrated into the protection layer) above, and this number was shown in Table 1.

{0057}

(Comparative example 6)

The sample of the leakage layer in Comparative example 6 was prepared in the same way as in Comparative example 5, except that the pressure of the stream of water to be jetted was adjusted to 1.75 MPa for the first jetting and to 3.5 MPa for the second blasting.

{0058}

(Comparative example 7)

The sample of the leakage layer in Comparative example 7 was prepared in the same way as in Comparative example 5, except that the pressure of the stream of water to be jetted was adjusted to 1 MPa for the first jet treatment and to 2 MPa. for the second blasting.

{0059}

The presence / absence confirmations and tests described above were performed on all samples of the leakage layer in the Examples and Comparative Examples described above. The results are shown in Table 1.

(1) Test to evaluate the prevention of fluid leakage

On filter paper (manufactured by Advantech Toyo Co., Ltd., No. 2, diameter: 70 mm), a sample obtained by cutting out 8 cm × 8 cm from the sample of the leakage protection layer was placed. In this case, the sample of the leakage protection layer was positioned so that the surface on the side 2B not facing the absorbent layer (the surface with the fleece area) was facing towards the filter paper. On the sample of the leakage layer, a sample cut to dimensions of 8 cm × 8 cm from a dry cellulose sheet (manufactured by Lion Corporation, Lead Healthy Cooking Paper Double (trade name), basis weight: 40 g / m ² ) was placed.

After that, 1.0 g of deionized water, which was included 0.005% of the mass. Blue No. 1 dye was injected from the top onto the dry cellulose sheet using a pipette. After injection, an acrylic plate with a diameter of 60 mm was applied to this sheet, and this plate was pressed on top for 5 seconds using a weight of 2 kg.

After squeezing for 5 seconds, the presence or absence of wetting of the filter paper (presence or absence of leakage) was confirmed by a method for visually confirming the color of the filter paper. The amount of deionized water seeped into the filter paper was determined by subtracting the pre-test weight from the post-test weight, and the weight was measured with an electronic balance.

1.0 g of the introduced deionized water was used assuming a state in which the entire leakage layer was wetted with liquid transferred from the absorbent layer to the leakage layer in the absorbent article. A weight with a mass of 2 kg was used with the assumption of a state in which the pressure due to the seated position would be applied when the absorbent article was worn.

(2) Test to evaluate softness:

Sensory softness assessment was performed by asking five test participants (persons involved in research on absorbent articles) to rub the surfaces (both surfaces) of each nonwoven sample with their hand. Thereafter, each trial participant was asked to score based on the evaluation criteria described below, with the mean of the scores given by five individuals taken as the score for the sensory softness of each sample.

The hot melt adhesive was dissolved using an organic solvent (butyl acetate) for a disposable diaper (manufactured by Kao Corporation, Merries (registered trademark), Merries Pants, size M, 2017) to peel off the outermost nonwoven (located on the non-skin side of the surface) ) and a film, which is a layer to prevent leakage, and the resulting sample was dried for one day with a jet of air and then used. The softness of this outermost (non-skin-facing) nonwoven fabric was scored 5 and the softness of the leakage layer film was scored 1, and from this the softness of each sample of the leakage control layer , quantitatively assessed on a five-point scale.

{0060}

Table 1

Example 1 Example 2 Example 3 Comparative example 1 Comparative example 2 Nonwoven structure SMS SMS SMS SMS SMS Nonwoven fabric treatment agent Hot stamping Hot stamping Hot stamping Hot stamping Hot stamping Meltblown layer Average fiber diameter (μm) 0.8 2.4 1.1 0.8 2.4 Surface density (g / m ² ) 10 10 10 10 10 Thickness (μm) 352 254 244 317 244 Filling rate (%) 3.1 4.3 4.5 3.5 4.5 Napping The whole surface The whole surface The whole surface Not processed Not processed Fibers of the meltblown layer that penetrate the protective layer
(fibers per 1 mm) 30.0 14.2 3.3 0.8 0.0 Presence or absence of through holes Absence Absence Absence Availability Availability The presence or absence of the meltblown layer exposed to the influence of fibers Absence Absence Absence Absence Absence Liquid Leakage Prevention (mg) 0 0 0 4 fourteen Softness 3.4 4.2 3.6 3.6 4.2

Table 1 (continued)

Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Comparative example 7 Nonwoven structure SMS SMS SM SM SM Nonwoven fabric treatment agent Hot stamping Hot stamping Hydrosputting Hydrosputting Hydrosputting Meltblown layer Average fiber diameter (μm) 3.5 1.1 2.4 2.4 2.4 Surface density (g / m ² ) 10 10 10 10 10 Thickness (μm) 234 43 145 168 182 Filling rate (%) 4.7 25.8 7.6 6.5 6.0 Napping The whole surface Not processed Not processed Not processed Not processed Fibers of the meltblown layer that penetrate the protective layer
(fibers per 1 mm) 24.2 0.0 23.3 19.2 7.5 Presence or absence of through holes Availability Availability Availability Availability Availability The presence or absence of the meltblown layer exposed to the influence of fibers Absence Absence Availability Availability Availability Liquid Leakage Prevention (mg) 27 24 193 121 72 Softness 4.4 2.0 3.4 3.4 3.2

{0061}

As shown in Table 1 above, the samples of the leakage protection layers in Examples 1 to 3, in which the number of fibers of the meltblown layer, which are fibers that penetrated into the protection layer, was 2.5 fibers or more per mm and in which the layers did not have through holes provided better liquid leakage prevention than the samples of the leakage layers in Comparative Examples 1, 2 and 4, in which the number of fibers of the meltblown layer, which are fibers that penetrated into the protective layer, was less than 2.5 fibers per mm and in which the layers had through holes. Likewise, the samples of the leakage layers in Examples 1-3, in which the layers had no through holes, provided better liquid leakage prevention even compared to the samples of the leakage layers in Comparative Examples 3 and 5-7, in which the layers had through holes even if the number of fibers of the meltblown layer, which are fibers that penetrated the backing layer, was 2.5 fibers per mm.

In particular, the samples of the leakage layers in Examples 1-3 provided significantly better liquid leakage prevention compared to the samples of the protection layers in Comparative Examples 5-7. This is due to the fact that when forming the nailed zone by the hydroentangling method, the movement of the fibers of the meltblown layer is provided under the action of the pressure of the water flow, which causes the formation of through holes with a cross-sectional area of 25 μm ² or more, in Comparative examples 5-7, while in Examples 1 -3, the tufted area was formed by tiling, and it was possible to suppress further movement of the fibers of the meltblown layer by hot stamping. In addition, this is also due to the fact that in the samples of the anti-leakage layers, in Examples 1-3, it was possible to prevent the situation in which the fibers of the meltblown layer were exposed to the upper surface on the side of the anti-leakage layer, which not facing the absorbent layer.

In addition, it was found that a softer texture could also be provided by limiting the degree of filling of the meltblown layer in Examples 1-3.

{0062}

The invention has been described in connection with these embodiments and Examples, it being understood that the invention should not be limited in any of the details in the description unless otherwise stated, but rather should be construed broadly within the spirit and scope of the accompanying document. claims.

{0063}

This application claims priority from Patent Application No. 2018-106250 filed in Japan on June 1, 2018 and Patent Application No. 2019-042349 filed in Japan on March 8, 2019, which are incorporated herein by reference in their entirety.

DESCRIPTION OF REFERENCE POSITIONS

{0064}

1 Top layer

2 Anti-leakage layer

3 Absorbent layer

4 Fibrous layer

6 Raised area

2A Absorbent side facing side of the leakage barrier

2B Side of the anti-leakage layer not facing the absorbent layer

21 Surface of the side of the anti-leakage layer that faces the absorbent layer

22 Surface of the side of the anti-leakage layer that does not face the absorbent layer

41 Layer meltblown

41A Brushed meltblown layer fiber

42, 43 Protective layer

42A Fiber Protective Layer

48 Fiber

49 Space

10 Absorbent article

Claims (22)

1. An absorbent article comprising a top layer, an anti-leakage layer and an absorbent layer sandwiched between the top layer and the anti-leakage layer, the leakage protection layer is applied directly to the absorbent layer, and the anti-leakage layer comprises a meltblown layer and a protective layer for the meltblown layer; wherein the leakage protection layer comprises an embossed portion in which the meltblown layer and the backing layer are bonded, and a non-embossed portion other than the embossed portion; wherein the leakage-proof layer includes a region without holes in the non-embossed portion; in this case, a zone without holes is a zone that does not contain a through hole, in which, in the top view of the layer that protects against leakage, the interfiber space containing a zone in which the area of a rectangle formed with a diagonal length of 10 μm reaches 25 μm ² or more, passes through in the thickness direction; and the area without holes is located in the entire area in which the leakage barrier overlaps the absorbent layer. 2. An absorbent article according to claim 1, wherein the average fiber diameter of the fibers of the meltblown layer is 2.5 µm or less. 3. An absorbent article comprising a topsheet, a leakage control layer, and an absorbent layer located between the topsheet and the leakage control layer, the leakage protection layer is applied directly to the absorbent layer, and the anti-leakage layer comprises a meltblown layer and a protective layer for the meltblown layer; wherein the leakage protection layer comprises an embossed portion in which the meltblown layer and the backing layer are bonded, and a non-embossed portion other than the embossed portion; the protective layer is located on the side of the meltblown layer, not facing the absorbent layer; the leakage protection layer comprises a piled area in which the number of fibers of the meltblown layer, which are fibers that penetrate into the protective layer, is 2.5 fibers / mm or more; the average diameter of the fibers constituting the fibers of the meltblown layer is 2.5 µm or less; and the nailed area is located in the area in which the leakage protection layer overlaps the absorbent layer. 4. Absorbent article according to any one of paragraphs. 1-3, in which the fibers of the meltblown layer are not exposed to the top surface on the side of the leakage barrier that does not face the absorbent layer. 5. Absorbent product according to any one of paragraphs. 1-4, in which the degree of filling of the meltblown layer with fibers is 25% or less. 6. Absorbent product according to any one of paragraphs. 1-5, in which the areal density of the meltblown layer is 20 g / m ² or less. 7. A method of making a nonwoven fabric, in which ultrafine fibers are collected on a belt conveyor by means of a meltblown method for continuously moving the starting material for the meltblown layer in the machine direction; teasing is applied to the surface of the starting material for the meltblown layer and the spunbond raw material is laminated to the nailed surface of the meltblown raw material by a spunbond process.

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