CN111032942A

CN111032942A - Non-woven fabric

Info

Publication number: CN111032942A
Application number: CN201880054643.0A
Authority: CN
Inventors: 濑户吉彦; 衣笠由彦
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2017-08-31
Filing date: 2018-07-17
Publication date: 2020-04-17
Anticipated expiration: 2038-07-17
Also published as: JP2019044293A; JP6594936B2; CN111032942B; WO2019044217A1; RU2736266C1

Abstract

A nonwoven fabric (10) having thermoplastic fibers and having a 1 st surface side (Z1) and a 2 nd surface side (Z2) has an outer surface fiber layer (1) on the 1 st surface side (Z1), an outer surface fiber layer (2) on the 2 nd surface side (Z2), a plurality of connecting portions (3) between the outer surface fiber layer (1) on the 1 st surface side (Z1) and the outer surface fiber layer (2) on the 2 nd surface side (Z2), and a hollow portion (4) between the connecting portions (3), wherein the hollow portion (4) is continuous in the plane direction of the nonwoven fabric (10).

Description

Non-woven fabric

Technical Field

The present invention relates to a nonwoven fabric.

Background

Nonwoven fabrics are often used in absorbent articles such as sanitary napkins and diapers. Techniques for imparting various functions to the nonwoven fabric are known.

For example, patent document 1 describes a nonwoven fabric having both surfaces formed with irregularities. The double-sided irregularities are formed by alternately arranging 1 st and 2 nd protrusions protruding in opposite directions to each other via an annular wall in different directions intersecting each other in a plan view. The 1 st and 2 nd protrusions have inner spaces open to the respective opposite surfaces, and the inner spaces are separated from each other by ridges and are discontinuous.

Patent document 2 describes a nonwoven fabric in which a 1 st layer and a 2 nd layer are laminated and bonded portions and non-bonded portions of the two layers are alternately arranged. The nonwoven fabric has protrusions in which the layer 1 protrudes and a cavity is formed in the non-joined portion, and has recesses in the joined portions between the protrusions. The projections and the recesses are arranged alternately and in a row in one direction, and the rows are arranged in a plurality of rows. In this arrangement, the hollow portions of the projections are not connected to each other, and a closed structure is formed.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012-136792

Patent document 2: japanese patent laid-open publication No. 2006-341455

Disclosure of Invention

The present invention provides a nonwoven fabric having thermoplastic fibers and having a 1 st surface side and a 2 nd surface side, the 2 nd surface side being the opposite side of the 1 st surface side, the nonwoven fabric having an outer surface fiber layer on the 1 st surface side, an outer surface fiber layer on the 2 nd surface side, a plurality of connecting portions between the outer surface fiber layer on the 1 st surface side and the outer surface fiber layer on the 2 nd surface side, and a hollow portion between the connecting portions, the hollow portion being continuous in a planar direction of the nonwoven fabric.

The above and other features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings.

Drawings

FIG. 1 is a partially sectional perspective view schematically showing a preferred embodiment of the nonwoven fabric according to the present invention.

FIG. 2 is a partially cut perspective view schematically showing a specific example of using the nonwoven fabric of FIG. 1 as a topsheet.

FIG. 3 is a cross-sectional view of the nonwoven fabric shown in FIG. 1 taken along line A-A.

FIG. 4 is a cross-sectional view of the nonwoven fabric shown in FIG. 1 taken along line B-B.

Fig. 5 is an explanatory view schematically showing an example of a preferred method for producing a nonwoven fabric according to the present embodiment, wherein (a) is an explanatory view showing a step of arranging a web on a support male member and pressing a support female member against the support male member from the web, (B) is an explanatory view showing a step of blowing a 1 st hot air from above the support female member to shape the web, and (C) is an explanatory view showing a step of removing the support female member and blowing a 2 nd hot air from above the shaped web to weld fibers to each other.

Fig. 6 is a sectional view showing arrangement of the projections of the male member, the projections of the female member, and the predetermined fibers in the planar direction in which the fibers are oriented in the thickness direction in the step of fig. 5 (B).

Detailed Description

The present invention relates to a nonwoven fabric having excellent air permeability within its thickness.

In an absorbent article such as a diaper or a sanitary napkin, the humidity of the interior increases due to sweat from the skin or water vapor from excrement while the absorbent article is worn on the body. When the humidity is too high, redness, itching, etc. of the skin may be caused, which may adversely affect the skin.

Since nonwoven fabrics are usually fiber aggregates formed into a sheet shape, air passages are small, and various studies have been made to improve air permeability. Examples thereof include nonwoven fabrics having openings. However, the nonwoven fabric is only perforated in the thickness direction, and the air permeability inside the nonwoven fabric other than the perforated portion is low. Such nonwoven fabric has room for further improvement in order to obtain air permeability to the extent that moisture in the absorbent article is ventilated. Further, even in the nonwoven fabric having a thickness due to the uneven shape of the internal space as in

patent documents

1 and 2, the internal spaces are separated from each other, and therefore, there is room for improvement in terms of improving the mobility of air and sufficiently reducing the humidity inside. On the other hand, in the conventional nonwoven fabric, even when the internal spaces are connected to each other without pressure, the internal spaces collapse due to squeezing or the like, and the air permeability is adversely inhibited.

The nonwoven fabric of the present invention has excellent air permeability within the thickness.

A preferred embodiment of the nonwoven fabric according to the present invention will be described below with reference to the drawings.

Fig. 1 shows a nonwoven fabric 10 according to the present embodiment. The nonwoven fabric 10 has a 1 st surface side Z1 and a 2 nd surface side Z2, and the 2 nd surface side Z2 is the opposite surface side of the 1 st surface side Z1. The 1 st surface side Z1 and the 2 nd surface side Z2 are the front surface and the back surface of the nonwoven fabric 10.

The nonwoven fabric 10 can be suitably used for a topsheet of an absorbent article such as a sanitary napkin or a disposable diaper. When used as a topsheet, any surface may be used so as to face the skin of the wearer. However, from the viewpoint of excellent air permeability and soft skin touch, it is preferable to use the surface side opposite to the surface in contact with hot air during production, that is, the 1 st surface side Z1, toward the skin surface side of the wearer because the number of fusion points of the fibers is small and the texture is smooth. Fig. 2 shows an example of a diaper 200 in which the nonwoven fabric 10 is disposed as a topsheet 201 so that the 1 st surface side Z1 faces the skin surface side of the wearer. That is, in this example, the outer surface fiber layer 1 on the 1 st surface side Z1 faces the skin surface side of the wearer. The diaper 200 includes a topsheet 201, a backsheet 202 on the wearing side, and an absorbent 203 sandwiched between the topsheet 201 and the backsheet 202. In this example, a side leakage preventing barrier (gather) 207 formed of a side sheet is provided. The diaper 200 is a belt type in which a fastening tape (fastening tape)206 on the back side R is fixed to the abdomen side F and is worn, but is not limited thereto, and may be a pants-type diaper. Further, the present invention can be applied to various absorbent articles other than diapers, for example, sanitary napkins and the like. In the present embodiment, the surface that is brought into contact with hot air during the production may be the 2 nd surface side Z2, and may have the same shape as the nonwoven fabric 10, or hot air may be blown from the 1 st surface side Z1 to increase the number of fusion points between the fibers on the 1 st surface side Z1. As described later, the nonwoven fabric 10 may have a structure in which the 1 st nonwoven fabric layer 5 and the 2 nd nonwoven fabric layer 6 are laminated, or may be constituted by only the 1 st nonwoven fabric layer 5 without the 2 nd nonwoven fabric layer 6.

In the following, an embodiment in which the 1 st surface side Z1 of the nonwoven fabric 10 shown in fig. 1 is used toward the skin surface will be considered. However, the present invention is not to be construed as being limited thereto.

The nonwoven fabric 10 of the present embodiment has thermoplastic fibers. At least a part of the fibers of the thermoplastic fibers are fused to each other at the intersection points. As will be described below, the nonwoven fabric 10 has a thickness shaped into a shape different from that of a conventional sheet-like nonwoven fabric.

Specifically, as shown in fig. 1, 3, and 4, the nonwoven fabric 10 includes the outer surface fiber layer 1 on the 1 st surface side Z1, the outer surface fiber layer 2 on the 2 nd surface side Z2, and a plurality of connecting portions 3 arranged between the outer surface fiber layer 1 on the 1 st surface side Z1 and the outer surface fiber layer 2 on the 2 nd surface side Z2 (hereinafter, the outer surface fiber layer 1 on the 1 st surface side Z1 and the outer surface fiber layer 2 on the 2 nd surface side Z2 are simply referred to as the outer surface fiber layer 1 and the outer surface fiber layer 2, respectively). The outer surface fiber layer 1, the outer surface fiber layer 2, and the coupling portion 3 are integrated with each other by fusing at least a part of the fibers to each other without a seam. The nonwoven fabric 10 is a bulky and thick nonwoven fabric in which the linking section 3 links and supports the outer surface fiber layer 1 on the 1 st surface side Z1 and the outer surface fiber layer 2 on the 2 nd surface side Z2. The thickness of the nonwoven fabric 10 is not limited to the thickness of only the outer

surface fiber layers

1 and 2 and the connecting portion 3, but means an apparent thickness of a shape formed by shaping the entire nonwoven fabric. In the present embodiment, the thickness is the thickness between the surface of the 1 st surface side Z1 and the surface of the 2 nd surface side Z2. This thickness is also referred to as the apparent thickness of the nonwoven fabric 10.

In the nonwoven fabric 10, the thermoplastic fibers are fused to each other at the intersections of at least some of the fibers even at portions other than the connecting portions between the outer

surface fiber layers

1 and 2 and the connecting portions 3. The nonwoven fabric 10 may have intersections where the thermoplastic fibers are not welded to each other. The nonwoven fabric 10 may contain fibers other than thermoplastic fibers, and may be welded at intersections between the thermoplastic fibers and the fibers other than thermoplastic fibers.

In the nonwoven fabric 10, the outer

surface fiber layers

1 and 2 constitute flat surfaces on both sides of the nonwoven fabric 10. The connecting portions 3 stand upright in the thickness direction of the nonwoven fabric 10. The coupling portions 3 are preferably coupled to the outer

surface fiber layers

1 and 2 perpendicularly like a pillar.

The nonwoven fabric 10 has a hollow portion 4 between the

connection portions

3 and 3. The hollow portion 4 is a space divided by the connecting portion 3 inside the nonwoven fabric 10. The surface and the back surface of the hollow portion 4, i.e., the 1 st surface Z1 side and the 2 nd surface Z2 side, are covered with the outer

surface fiber layers

1 and 2, and preferably are not perforated in the thickness direction.

The "hollow portion" referred to herein is a space that is not substantially filled with the fibers of the nonwoven fabric. Specifically, the hollow part 4 is located inside the nonwoven fabric 10, and the amount of fibers is 20 fibers/mm²Hereinafter, from the viewpoint of air permeability, a space in which no fiber is arranged is preferable.

(method of measuring fiber amount)

The above-mentioned fiber amount was measured in the following manner.

The nonwoven fabric 10 is cut in the thickness direction so as to pass through a portion to be measured (for example, between the connection portions). The cut surface was observed under magnification using a scanning electron microscope, and the number of cross sections of the fiber cut per a predetermined area of the cut surface was counted. The magnification of about 30 to 60 fibers (150 times or more and 500 times or less) can be measured by observing and adjusting the cross section of the fiber under magnification. Then, the conversion is made to 1mm per unit²The number of cross sections of the fibers (2) is set to a fiber density (root/mm)²). The measurements were made at 3 points, respectively, and averaged to set the fiber density of the sample. The scanning electron microscope used was JCM-5100 (trade name) manufactured by Nippon electronic Co.

The hollow portion 4 is continuous in the planar direction of the nonwoven fabric 10. This "continuation" may be a state in which the respective regions of the hollow portion 4 divided by the coupling portion 3 are connected in the planar direction, or may be a state in which 1 hollow portion extends in the planar direction. The hollow portion 4 is formed with a through air passage by this continuity. In the air passage formed by the hollow portion 4, air can be discharged from the inside of the thickness of the nonwoven fabric (between the outer surface fiber layer 1 on the 1 st surface side Z1 and the outer surface fiber layer 2 on the 2 nd surface side Z2) to the outside in the planar direction of the nonwoven fabric. During the exhaust, air can be introduced into the hollow portion 4 through the outer

surface fiber layers

1 and 2. Thereby, the air is metabolized around and in the nonwoven fabric 10. This effect is more effectively exhibited when the nonwoven fabric 10 is pressed in the thickness direction.

In this way, the nonwoven fabric 10 has a structure in which air is removed in the planar direction in the hollow portion 4 sandwiched between the outer

surface fiber layers

1 and 2, and thus has excellent air permeability horizontally rearward in the thickness of the nonwoven fabric. Further, when the nonwoven fabric 10 is incorporated as a component of an absorbent article (for example, a topsheet that contacts the skin, or an intermediate sheet between the topsheet and the liquid-retentive absorbent member), the humidity in the absorbent article can be effectively reduced during use.

From the viewpoint of further improving the air permeability of the nonwoven fabric 10, the hollow portion 4 is preferably continuous along a plurality of different directions intersecting in a plan view.

Further, the nonwoven fabric 10 has: the

coupling portions

3, 3 defining the hollow portion 4 support the plane of the outer surface fiber layers 1, 2 in the thickness direction. This makes the three-dimensional structure of the nonwoven fabric 10 less likely to collapse and makes it easier to recover the shape after pressing. The result is: the nonwoven fabric 10 can maintain the air permeability inside the nonwoven fabric 10 due to the hollow portion 4, and the effect of reducing the humidity of the absorbent article incorporating the nonwoven fabric 10 is sustained, thereby providing an excellent effect on the skin.

In addition, from the viewpoint of maintaining the space of the hollow portion 4 without easily collapsing the three-dimensional structure described above, the coupling portion 3 preferably has a wall surface including: the height of the nonwoven fabric 10 in the thickness direction and the extension length (width) of the nonwoven fabric 10 in the planar direction along the extension direction of the outer surface fiber layers 1, 2. From the same viewpoint, it is preferable that the wall surface of the connecting portion 3 is arranged along a plurality of different directions intersecting with each other in a plan view of the nonwoven fabric.

In the nonwoven fabric 10, the hollow portions 4 are preferably connected without a barrier to air movement, and more preferably connected in a straight line. This is due to: the loss due to the bending of the air flow caused by the obstacle and the flow path is reduced, and the above-described ventilation inside is effectively realized. Similarly, in order to reduce the loss due to the obstacle, the ventilation path formed by the hollow portion 4 is preferably a tubular space in which the inside of the nonwoven fabric 10 travels in the planar direction. The air passage preferably reaches an end of the nonwoven fabric 10.

The nonwoven fabric 10 has a thickness (large volume) sufficient for ensuring the air passage without increasing the fiber amount due to the three-dimensional structure of the outer

surface fiber layers

1 and 2 and the connecting portion 3 in the thickness direction. Therefore, the nonwoven fabric 10 has flexibility because it is bent without resistance when the nonwoven fabric is bent, as compared with a nonwoven fabric having a thickness by increasing the fiber amount only.

The nonwoven fabric 10 is preferably in the following ranges in thickness and basis weight from the viewpoint of excellent air permeability.

The apparent thickness of the nonwoven fabric as a whole is preferably 2mm or more, more preferably 3mm or more, and further preferably 4mm or more. The upper limit of the apparent thickness is not particularly limited, but when used as a topsheet for an absorbent article, from the viewpoint of good portability, the upper limit is preferably 10mm or less, more preferably 9mm or less, and still more preferably 8mm or less.

The weight per unit area of the nonwoven fabric 10 having the apparent thickness is preferably 80g/m²Hereinafter, more preferably 70g/m²Hereinafter, more preferably 60g/m²The following. The lower limit of the weight per unit area is not particularly limited, but is preferably 8g/m from the viewpoint of making the nonwoven fabric have a good texture and forming air flow paths from the beginning to the end²Above, more preferably 10g/m²Above, more preferably 15g/m²The above.

(method of measuring apparent thickness and weight per unit area of nonwoven Fabric 10)

(1) Method for measuring apparent thickness of nonwoven fabric:

the nonwoven fabric to be measured was cut into 10cm × 10 cm. In the case where 10cm × 10cm cannot be obtained, the cutting is performed to an area as large as possible. The thickness under a load of 50Pa was measured using a laser thickness meter (ZLD 80 (trade name) manufactured by OMRON K.K.). Three portions were measured, and the average value was defined as the apparent thickness of the nonwoven fabric 10.

(2) The method for measuring the weight per unit area of the non-woven fabric comprises the following steps:

the nonwoven fabric to be measured was cut into 15cm × 15 cm. In the case where 10cm × 10cm cannot be obtained, the cutting is performed to an area as large as possible. The weight was measured using a balance, divided by the area, and used as the weight per unit area.

(3) In the measurement of (1) and (2), when a commercially available absorbent article is used, the adhesive used in the absorbent article is cured by a cooling method such as cold spray (cold spray), and the nonwoven fabric to be measured is carefully peeled off and measured. At this time, the adhesive is removed using an organic solvent. The same applies to the measurement of other nonwoven fabrics in the present specification.

Next, a more specific structure of the nonwoven fabric 10 in the present embodiment will be described with reference to fig. 1, 3, and 4.

In the present embodiment, the nonwoven fabric 10 is a laminate of the 1 st nonwoven fabric layer 5 on the 1 st surface Z1 side and the 2 nd nonwoven fabric layer 6 on the 2 nd surface Z2 side. The nonwoven fabric 10 has the following three-dimensional structure, and has an uneven surface on one surface side.

That is, the 1 st nonwoven fabric layer 5 includes the outer surface fiber layer 1 on the 1 st surface Z1 side and the connection portions 3, and the 2 nd nonwoven fabric 6 constitutes the outer surface fiber layer 2 on the 2 nd surface Z2 side. The 1 st nonwoven fabric layer 5 has recesses 7 open on the 1 st surface Z1 side, and has an uneven surface 8 on the 1 st surface Z1 side based on the recesses 7 and the outer surface fiber layer 1. On the other hand, the 2 nd nonwoven fabric 6 has a substantially flat shape, and is arranged continuously in a planar shape over the entire 2 nd surface Z2 side as the outer surface fiber layer 2 on the 2 nd surface Z2 side of the nonwoven fabric 10. The 2 nd nonwoven fabric 6 may be completely flat or may have a slight step. From the viewpoint of securing the air flow path, it is preferable to make it flat. The height difference of the 2 nd nonwoven fabric 6 is smaller than the height difference of the 1 st outer surface fiber layer 11 and the recess bottom 71. The term "substantially flat" as used herein means that the difference in height between the irregularities is smaller than the difference in height between the 1 st outer surface fiber layer 11 and the recessed portion bottom 71.

In this way, in the nonwoven fabric 10, the uneven surface 8 is preferably disposed with the recessed portion 7 opening to the 1 st surface side Z1, which is one surface side. Air can be taken into the concave portion 7, and the above air permeability can be improved. Further, it is possible to embody: the characteristic cushioning property of local subsidence of the concave portion 7 is generated while the three-dimensional structure of the nonwoven fabric 10 is maintained. In addition, from the viewpoint of shape recovery property at the time of compression, the concave portion 7 is preferably surrounded by the wall surface constituted by the above-described coupling portion 3. The relationship between the recess 7 and the hollow 4 passing through the coupling portion 3 will be described later.

Further, in the 1 st nonwoven fabric layer 5, the recess 7 has a recess bottom 71 formed of the fiber layer of the 1 st nonwoven fabric 5 on the 2 nd surface side Z2. The recess bottom 71 is joined in contact with the 2 nd nonwoven fabric layer 6 to constitute a part of the outer surface fiber layer 2. That is, in the present embodiment, the outer surface fiber layer 2 on the 2 nd plane Z2 side partially has a 2-layer structure at the position where the concave portion 7 is disposed. The 2-layer structure is arranged in a plurality of numbers in the plane direction of the 2 nd surface Z2 side, so that the strength of the nonwoven fabric 10 on the 2 nd surface Z2 side is improved, and the deformation of the 2 nd surface Z2 side is suppressed. By the support based on the 2-layer structure, the entire three-dimensional structure of the nonwoven fabric 10 is less likely to collapse. The space of the recess 7 is partitioned by the recess bottom 71 as a bottom and the coupling portion 3 as a wall. The connecting portion 3 connects the end of the outer surface fiber layer 1 and the end of the recess bottom portion 71.

The hollow portion 4 is provided between the 1 st nonwoven fabric layer 5 and the 2 nd nonwoven fabric layer 6. Specifically, the hollow portion 4 is located in a region surrounded by the outer surface fiber layer 2 composed of the outer surface fiber layer 1 of the 1 st nonwoven fabric layer 5, the coupling portion 3, and the 2 nd nonwoven fabric layer 6. Unlike the recess 7, the hollow portion 4 has no opening in the thickness direction, and covers the front and rear surfaces with the outer surface fiber layer 1 and the outer surface fiber layer 2, as described above. The hollow portion 4 and the recess portion 7 are adjacent to each other via the connection portion 3 as a common wall portion. This point will be described later in detail.

In the 1 st nonwoven fabric layer 5 of the present embodiment, the outer surface fiber layer 1 on the 1 st surface side Z1 has 2 types of portions. The 2 nd outer surface fiber layers 11 and 12 are disposed on the 1 st surface side Z1 in part. They have lengths extending in different directions intersecting the nonwoven fabric 10 in a plan view. The extending directions are X and Y directions orthogonal to each other along the sides of the nonwoven fabric 10. The Y direction is the longitudinal direction of the nonwoven fabric 10, and the X direction is the width direction of the nonwoven fabric 10.

In the 2 types of portions, one 1 st outer surface fiber layer 11 continuously extends in the Y direction in a plan view of the nonwoven fabric 10, and is continuous over the entire length of the nonwoven fabric 10. The 1 st outer surface fiber layer 11 extending in the Y direction is arranged in a plurality spaced from each other along the X direction orthogonal to the Y direction.

The other 2 nd outer surface fiber layer 12 extends in the X direction and is disposed so as to connect the 1 st outer surface fiber layers 11 and 11 arranged at intervals in the X direction. "connecting the 1 st outer surface fiber layers 11 and 11" means that the 2 nd outer surface fiber layers 12 adjacent to each other are arranged linearly with the 1 st outer surface fiber layer 11 interposed therebetween. Specifically, the deviation of the width center line of the 2 nd outer surface fiber layer 12 extending in the X direction from the width center line of the 2 nd outer surface fiber layer 12 extending in the X direction adjacent to the 1 st outer surface fiber layer 11 with the 1 st outer surface fiber layer interposed therebetween means a range of the width (length in the Y direction) of the 2 nd outer surface fiber layer 12, and means, for example, within 5 mm. The 2 nd outer surface fiber layer 12 is located slightly lower than the 1 st outer surface fiber layer 11 on the 1 st surface side Z1. Therefore, the 2 nd outer surface fiber layer 12 is cut by the 1 st outer surface fiber layer 11 in the X direction, and a plurality of the layers are spaced apart from each other and aligned in the X direction. The width (width in the Y direction) of the 2 nd outer surface fiber layer 12 is narrower than the width (width in the X direction) of the 1 st outer surface fiber layer 11. A plurality of such rows of the 2 nd outer surface fiber layer 12 in the X direction are further arranged spaced apart from each other in the Y direction. The shape of the 2 nd outer surface fiber layer is not limited to the shape of the present embodiment, and the position and width of the 1 st surface side Z1 may be the same as those of the 1 st outer surface fiber layer 11, for example. However, the 2 nd outer surface fiber layer 12 is preferably formed in the form of the present embodiment because the application of the pressing force in the planar direction can be suppressed.

When the outer surface fiber layer 1 includes a plurality of portions having different extending directions as described above, the "different directions intersecting in plan view" forming the extending directions is not limited to the X direction and the Y direction. The nonwoven fabric 10 may take various forms as long as it is oriented in a direction intersecting the plane direction thereof. As described later, the intersection angle of the "different directions intersecting in plan view" is most preferable from the viewpoint of further improving the compression recovery property to the cushioning property after the compression deformation of the nonwoven fabric 10 and the viewpoint of facilitating the production of the longitudinally oriented fiber of the connecting portion: the Cross angle (90 DEG) between the mechanical flow (MD) Direction of the surface fibers of the nonwoven fabric and the Cross Direction (Cross Direction) perpendicular thereto.

In the 1 st nonwoven fabric layer 5, a plurality of the recess bottoms 71 are arranged so as to be spaced apart from each other. Specifically, the recess bottom portion 71 covers the separation space between the 1 st outer surface fiber layers 11 and 11 on the 1 st surface Z1 on the 2 nd surface Z2, and is arranged in a plurality of rows spaced from each other along the extending direction (Y direction) of the outer surface fiber layers 11. Further, a plurality of rows of the recess bottom portions 71 in the Y direction are arranged so as to be spaced apart from each other in the X direction orthogonal to the Y direction. That is, the recess bottom portions 71 are also arranged in the X direction. Thus, the arrangement direction of the recess bottom portions 71 coincides with the extending direction of the outer surface fiber layer 1. Therefore, when the extending direction of the outer surface fiber layers 1 is different from the X direction and the Y direction, the arrangement direction of the outer surface fiber layers 2 is also different from the X direction and the Y direction correspondingly.

Further, the coupling portion 3 has 2 kinds of portions. One is the 1 st coupling part 31 which connects the 1 st outer surface fiber layer 11 on the 1 st surface side Z1 and the recess bottom 71 on the 2 nd surface side Z2 in the thickness direction. The other is the 2 nd coupling part 32 which connects the 2 nd outer surface fiber layer 12 on the 1 st surface side Z1 and the recess bottom 71 on the 2 nd surface side Z2 in the thickness direction. The plurality of coupling portions 3 (the 1 st coupling portion 31 and the 2 nd coupling portion 32) are arranged so as to be spaced apart from each other in the planar direction of the nonwoven fabric 10, according to the spaced arrangement of the outer surface fiber layer 1 and the recess bottom portion 71.

The coupling portion 3 couples the outer surface fiber layer 1 and the end of the recess bottom 71 to each other. More specifically, the 1 st connecting portion 31 connects the end portion 11A of the 1 st outer surface fiber layer 11 and the end portion 71A of the recess bottom 71. On the other hand, the 2 nd coupling portion 32 couples the end portion 12A of the 2 nd outer surface fiber layer 12 and the end portion 71A of the recess bottom portion 71.

As described above, the coupling portion 3 has the wall surface having the height in the thickness direction and the width extending in the planar direction, and the coupling portion 3 connects the outer surface fiber layer 1 and the recess bottom portion 71 in the plane. From the viewpoint of maintaining the three-dimensional structure of the nonwoven fabric 10, partial sinking, and good compression recovery properties, the wall surface formed by the connecting portion 3 is preferably arranged along a plurality of different directions intersecting with each other in a plan view of the nonwoven fabric 10 as described below.

Specifically, the 1 st coupling part 31 includes a wall surface along the 1 st outer surface fiber layer 11 extending direction of the 1 st surface side Z1, the wall surface having a length (width) corresponding to the side in the Y direction of the recess bottom 71 of the 2 nd surface side Z2. That is, the wall surface of the 1 st coupling part 31 is arranged along the Y direction. On the other hand, the 2 nd connecting part 32 includes a wall surface along the extending direction of the 2 nd outer surface fiber layer 12 on the 1 st surface side Z1, and the wall surface has a length (width) corresponding to the side in the X direction of the recess bottom 71 on the 2 nd surface side Z2. That is, the wall surface of the 2 nd coupling part 32 is arranged along the X direction. In this way, the direction of the coupling portion 3 (the 1 st coupling portion 31 and the 2 nd coupling portion 32) along the wall surface coincides with the extension of the outer surface fiber layer 1. Therefore, when the extending direction of the outer surface fiber layer 1 is different from the X direction and the Y direction, the direction of the connecting portion 3 along the wall surface is also different from the X direction and the Y direction.

Since the 1 st coupling part 31 and the 2 nd coupling part 32 have the assembly structure intersecting as described above, the strength of the column supporting the outer

surface fiber layers

1 and 2 is increased. This makes the nonwoven fabric 10 have a high shape retention property of the three-dimensional structure, and maintains high air permeability due to the hollow portion 4.

The hollow portion 4 also has 2 kinds of portions. One part of the hollow portion 4 is a 1 st hollow portion 41 in a region surrounded by the 1 st outer surface fiber layer 11, the 1 st coupling portion 31, and the outer surface fiber layer 2. The other part is a 2 nd hollow portion 42 in a region surrounded by the 2 nd outer surface fiber layer 12, the 2 nd coupling portion 32, and the outer surface fiber layer 2.

As described above, from the viewpoint of air permeability, the hollow section 4 is preferably continuous along a plurality of different directions intersecting in a plan view of the nonwoven fabric 10.

In the present embodiment, the 1 st hollow portion 41 extends along the extending direction (Y direction) of the 1 st outer surface fiber layer 11 and the 1 st coupling portion 31, and is continuous in the Y direction. Thus, the 1 st hollow portion 41 forms a ventilation passage 41A penetrating in the Y direction. On the other hand, the 2 nd hollow portion 42 extends along the extending direction (X direction) of the 2 nd outer surface fiber layer 12 and the 2 nd coupling portion 32, and is continuous in the X direction intersecting the Y direction. Thereby, the 2 nd hollow portion 42 forms a ventilation passage 42A penetrating in the X direction. A plurality of rows of these

air passages

41A and 42A are arranged. The

respective air passages

41A and 42A are connected to each other in the intersecting region, and form a communicating space. In this way, the hollow portions 4 formed by the 1 st hollow portion 41 and the 2 nd hollow portion 42 are connected in different directions (X direction and Y direction) intersecting each other in the plane direction of the nonwoven fabric 10 inside the nonwoven fabric 10.

In this way, the hollow portion 4 includes a plurality of portions continuous in different directions (X direction and Y direction) intersecting each other in the plane direction of the nonwoven fabric 10, and is connected in a mesh shape. The hollow portions 4 connected in a mesh shape have no barrier by the fiber layers (for example, the outer

surface fiber layers

1 and 2 and the connecting portion 3) of the nonwoven fabric 10, and air can move in a vertical and horizontal direction endlessly through the tubular spaces of the

air passages

41A and 42A. By connecting the hollow portions 4 in a mesh shape in this way, even if a part of the plurality of ventilation paths existing is collapsed, the air can be continuously metabolized in conjunction with other ventilation paths. The continuity of the air flow through the hollow portion 4 is further improved by the structure in which the coupling portion 3 defining the hollow portion 4 supports the plane of the outer

surface fiber layers

1 and 2.

The directions in which the hollow portions 4 are connected to each other are not limited to the 2 directions X and Y, and may be various directions, as long as they are different directions intersecting each other in the plane direction of the nonwoven fabric 10. The different directions intersecting each other are not limited to 2 directions, and may be 3 directions or more.

From the viewpoint of effectively exhibiting the above-described function, the flow passage area of the air passage constituted by the hollow portion 4 is preferably in the following range in cross section.

The flow path area of the ventilation path 41A constituted by the 1 st hollow part 41 is preferably 1.5mm per 1 flow path in the cross section²Above, more preferably 2.3mm²Above, more preferably 3mm²The above. In addition, the flow path area of the air passage 41A is preferably 7.8mm per 1 flow path in the cross section from the viewpoint of securing the strength of the nonwoven fabric²Hereinafter, more preferably 7mm²Hereinafter, more preferably 6.2mm²The following. Specifically, the flow path area of the air flow path 41A is preferably 1.5mm per 1 flow path²Above and 7.8mm²Hereinafter, more preferably 2.3mm²Above and 7mm²Hereinafter, more preferably 3mm²Above and 6.2mm²The following.

Similarly, the flow path area of the air passage 42A formed by the 1 st hollow portion 42 is preferably 2.3mm per 1 flow path in the cross section²Above, more preferably 3.5mm²Above, more preferably 4.5mm²The above. In addition, from the viewpoint of securing the strength of the nonwoven fabric, the flow path area of the air passage 42A is preferably 11.6mm per 1 flow path in the cross section²Hereinafter, more preferably 10.5mm²Hereinafter, more preferably 9.3mm²The following. Specifically, the flow path area of the ventilation path 42A is preferably 2.3mm²Above and 11.6mm²Hereinafter, more preferably 3.5mm²Above and 10.5mm²Hereinafter, more preferably 4.5mm²Above and 9.3mm²The following.

The flow path area of the air passage 41A is preferably smaller than the flow path area of the air passage 42A.

(method of measuring flow passage area of air passage in hollow section 4)

The nonwoven fabric to be measured is cut at right angles to the direction in which the hollow portion extends, to obtain a cut surface of the hollow portion. The area of the hollow portion 4, i.e., the area of the ventilation path, was measured by magnifying the cut surface to a size (10 to 100 times) that the cut surface can sufficiently enter the visual field and measuring the cut surface with a digital microscope (trade name: VHX-1000) manufactured by KEYENCE.

From the viewpoint of keeping the space of the hollow portion 4, the connecting portion 3 is preferably a portion in which fibers are oriented in the thickness direction of the nonwoven fabric 10.

Here, the fibers of the connecting portions 3 are oriented in the thickness direction of the nonwoven fabric 10, which means that the longitudinal orientation ratio of the fibers is 60% or more, which is obtained by a measurement method described later. The connecting portions 3 can be said to be disposed vertically in the thickness direction of the nonwoven fabric 10 by the longitudinal orientation ratio of the fibers having this range.

The connecting portion 3 is erected in a columnar state by setting the longitudinal orientation ratio of the fibers to 60% or more and having local fusion bonding of the fibers, and gives an appropriate elastic force to the nonwoven fabric 10 in the thickness direction. In contrast, since the fibers of the conventional nonwoven fabric do not have the longitudinal orientation ratio of the fibers as in the connection portion 3 of the present embodiment, the nonwoven fabric is deformed to fill the space between the fibers by the force applied when the nonwoven fabric is pressed in the thickness direction, and the amount of deformation is increased by the force. However, in the present embodiment, the coupling portion 3 supports the outer

surface fiber layers

1 and 2 like a column and is perpendicular to the thickness direction, and therefore can withstand a slight force from the same direction. Further, in the present embodiment, when a large force is applied, the column is deformed so as to be broken. That is, deformation (hereinafter, also referred to as buckling deformation) that is not possessed by the conventional nonwoven fabric or is close to the so-called buckling phenomenon occurs. However, even when the connecting portion is bent as in the buckling phenomenon, the nonwoven fabric 10 can be restored to the original thickness by the elastic force of the constituent fibers.

From the viewpoint of cushioning properties, the longitudinal orientation ratio of the fibers of the connecting portion 3 defined above is preferably 63% or more, and more preferably 65% or more. More preferably 68% or more. The upper limit is not particularly limited, and the longitudinal orientation ratio is preferably 90% or less, more preferably 85% or less, and even more preferably 80% or less, from the viewpoint of producing a structure in which the fibers intersect with each other to form a weld, and the fibers form a columnar shape to produce a resistance. Specifically, the longitudinal orientation ratio of the coupling portion 3 is preferably 63% or more and 90% or less, more preferably 65% or more and 85% or less, and further preferably 68% or more and 80% or less.

In the present embodiment, the outer surface fiber layer 1 and the outer surface fiber layer 2 are portions where fibers are oriented in the planar direction on the front surface and the back surface (the 1 st surface side Z1 and the 2 nd surface side Z2) of the nonwoven fabric 10, respectively.

Here, "the fibers are oriented in the plane direction" means that the longitudinal orientation ratio of the fibers is less than 45% by a measurement method described later. When the longitudinal orientation ratio of the fibers is less than 45%, the fibers can be sufficiently aligned in the planar direction and maintain a flat shape. In the outer surface fiber layer oriented in the planar direction, the longitudinal orientation ratio of the fibers is preferably 0% or more, more preferably 30% or more, from the viewpoint of shape retention and strength retention of the nonwoven fabric. The longitudinal orientation ratio of the fibers in the outer surface fiber layer 1 and the outer surface fiber layer 2 is preferably 38% or less, more preferably 37% or less, because it is easy to contact the plane as in a normal flat nonwoven fabric.

In the connection portion 3, since the outer

surface fiber layers

1 and 2 in which the fibers are oriented in the planar direction are connected at the end portions without a seam, the fibers oriented in the planar direction and the fibers oriented in the thickness direction are mixed in the portion. In this portion, a portion up to the definition falling within the above range is defined as the coupling portion 3. In the portion where the fibers oriented in the planar direction and the fibers oriented in the thickness direction are mixed, the longitudinal orientation ratio of the fibers preferably shows an oblique orientation of 45% or more and 60% or less, and the longitudinal orientation ratio of the fibers is more preferably shifted from 45% to 60% in a stepwise longitudinal orientation and to a sufficient longitudinal orientation.

(method of measuring the longitudinal orientation ratio of the fibers in the connecting section 3 and the outer surface fiber layers 1 and 2)

(1) Production of non-woven Fabric section

A cross section in the thickness direction, which is orthogonal to the direction in which the coupling portion 3 extends in the planar direction and passes through the center of the extended length, is formed as a cross section (longitudinal cross section) of the nonwoven fabric passing through the outer surface fiber layer 1 on the 1 st surface side and the outer surface fiber layer 2 on the 2 nd surface side. Alternatively, when the nonwoven fabric 10 has the hollow portion 4 as described later, a cross section (longitudinal cross section) of the nonwoven fabric passing through the 1 st surface side outer surface fiber layer 1 and the 2 nd surface side outer surface fiber layer 2 in the thickness direction passing through the center of the hollow portion 4 is formed. For example, a cross section in the thickness direction of fig. 1 (fig. 3 and 4) is formed along the line a-a and the line B-B. The cross section in the thickness direction passing through the line a-a shown in fig. 3 is a cross section perpendicular to the longitudinal direction (Y direction) of the nonwoven fabric extending from the 1 st linking part 31. The cross section in the thickness direction passing through the line B-B shown in fig. 4 is a cross section perpendicular to the width direction (X direction) of the nonwoven fabric extending from the 2 nd connecting portion 32. The cross section is a cross section obtained by cutting a nonwoven fabric to be measured into 5mm × 5mm or more.

(2) Measurement of the longitudinal orientation ratio of the fibers of the connecting part 3 and the outer

surface fiber layers

1 and 2

The cross section in the thickness direction was observed by SEM (product name of JCM-5100, manufactured by Nippon electronics Co., Ltd.) at 35 times magnification. A square line of 0.5mm by 0.5mm was prepared as a reference line in the observation image. Each side (reference line) of the square is a side orthogonal to the thickness direction and the plane direction in the cross section of the nonwoven fabric. The number of fibers extending through a reference line formed by each side of the square was counted. The fibers passing through the reference line of a square orthogonal to the plane direction of the nonwoven fabric are defined as the "number of transverse fibers", and the fibers passing through the reference line of a square orthogonal to the thickness direction of the nonwoven fabric are defined as the "number of longitudinal fibers". The longitudinal orientation ratio was calculated as (number of longitudinal fibers)/(number of transverse fibers + number of longitudinal fibers) × 100 ═ longitudinal orientation ratio (%). These were measured at 4 points, and the average value was used as the value of the longitudinal orientation ratio. The outer surface fiber layer and the joint portion were cut out and measured.

The connecting portion 3 has the above-described orientation of the fibers, and thus the fiber layers defining the space of the hollow portion 4 are less likely to collapse due to the pressing force in the thickness direction. Even if buckling deformation occurs due to a strong pressing force, the shape recovery of the coupling portion 3 is high. That is, the pressing force in the thickness direction is elastically maintained by the orientation of the fibers of the coupling portions 3 and is buckled and deformed, and when the nonwoven fabric 10 sinks and the compressive deformation is released, the nonwoven fabric 10 returns to the original apparent thickness by the elasticity of the fibers of the coupling portions 3. As a result, the nonwoven fabric 10 recovers its cushioning property even when repeatedly contacted, and the sustained cushioning property can be enhanced.

Further, when the pressing force in the thickness direction of the nonwoven fabric 10 is applied by the fiber orientation in the connection portion 3, the pressing force is more likely to be concentrated in the thickness direction than when the pressing force is dispersed in the planar direction from the vicinity of the force point. Therefore, the spread of the pressing force in the planar direction is suppressed, and the nonwoven fabric 10 locally sinks near the point of force.

Accordingly, the orientation in the fiber thickness direction in the connecting portion 3 is combined with the planar structure in which the outer

surface fiber layers

1 and 2 are supported in the thickness direction by the surface of the connecting portion 3 and the structure in which the hollow portion 4 is connected to form a net, and thus the nonwoven fabric 10 can maintain high air permeability and exhibit air metabolism more continuously.

The orientation of the fibers in the thickness direction in the connecting portion 3 is preferably provided in at least one of the 1 st connecting portion 31 and the 2 nd connecting portion 32 having different orientations of the above-described surfaces, and more preferably provided in both the 1 st connecting portion 31 and the 2 nd connecting portion 32.

In the present embodiment, in both of the first connecting portion 31 and the second connecting portion 32 having different plane orientations, the fibers are oriented in the thickness direction of the nonwoven fabric 10. This means that the connecting portions 3 are oriented in the thickness direction regardless of the longitudinal direction and the width direction of the nonwoven fabric 10. If a nonwoven fabric in which fibers are substantially randomly oriented and fused is formed into irregularities as in a conventional nonwoven fabric, it is not possible to orient the connecting portions 3 in such different directions in the thickness direction. Even if oriented, it is only one direction of the machine flow (MD) direction in the manufacture of nonwoven fabrics. In contrast, the nonwoven fabric 10 of the present embodiment has the above-defined fiber orientation in the thickness direction in both the connection portions 3 facing in any direction (in the present embodiment, the

connection portions

31 and 32 having mutually orthogonal surfaces).

Accordingly, the buckling deformation of the connecting portion 3 can be appropriately generated not only when the pressing force is applied vertically but also when the pressing force is applied obliquely or when the pressing force is applied as a shear force in multiple directions, and excellent cushioning properties with appropriate elasticity of the nonwoven fabric 10 can be exhibited.

Next, the relationship between the recess 7 and the hollow 4 passing through the coupling portion 3 will be described.

In the nonwoven fabric 10, the concave portion 7 opening toward the first surface Z1 is disposed in a region where the hollow portion 4 is not disposed. As described above, the hollow portion 4 and the recess portion 7 are adjacent to each other with the connecting portion 3 as a common wall portion interposed therebetween. The recess 7 is disposed adjacent to both the first hollow portion 41 and the second hollow portion 42 by a configuration described below.

The recess 7 is formed by surrounding the periphery in the planar direction with the wall surfaces of the four connecting portions 3 erected from the four sides of the recess bottom portion 71. A plurality of concave portions 7 having such a structure are arranged so as to be spaced apart from each other in the X direction and the Y direction. In this arrangement, the recesses 7 are independent of each other without communicating with each other. In the present embodiment, the four coupling portions 3 and the recess bottom portion 71 surrounding the recess 7 are formed in a shape of a prism or a frustum. However, the shape of the recess 7 is not limited thereto, and may be various shapes as long as the function described later is achieved.

The four coupling portions 3 defining the recess 7 are two first coupling portions 31 and two second coupling portions 32. The first connecting portion 31 is disposed with the surface along the Y direction facing each other, and the second connecting portion 32 is disposed with the surface along the X direction facing each other, and they are combined to intersect each other.

In one configuration, the recess 7 is adjacent to the first hollow portion 41 by the first connecting portion 31 and adjacent to the second hollow portion 42 by the second connecting portion 32. Thereby, in the recess 7, the sucked air can be supplied to both the 1 st hollow portion 41 and the 2 nd hollow portion 42 at the same time. Further, air can be sent into the first hollow portion 41 and the second hollow portion 42 from the side through the first connecting portion 31 and the second connecting portion 32. This allows the nonwoven fabric 10 to continue to suck air into the hollow portion 4 even when the nonwoven fabric is pressed in the thickness direction.

The presence of the recessed portions 7 has a function of suppressing the spread of the pressing force in the planar direction of the nonwoven fabric 10, in addition to the fiber orientation of the connecting portions 3. That is, the outer surface fiber layer 1 on the 1 st surface Z1 side is less likely to sink as a whole due to the presence of the concave portions 7. This makes it possible to more effectively exhibit compression deformation (buckling deformation) defined in the vicinity of the force point of the pressing force in the nonwoven fabric 10. At this time, the presence of the intersecting portion between the connecting portions 3 surrounding the recessed portion 7 facilitates maintenance of the three-dimensional structure of the entire nonwoven fabric 10 in addition to the above-defined fiber orientation in the thickness direction. This can provide a high shape recovery property after buckling deformation is generated at the portion other than the intersection of the coupling portion 3, and can further improve the cushioning property.

Further, by opening the concave portion 7 to the 1 st surface side Z1, it can partially enter the skin surface of a human body to be pressed, for example, a finger. Accordingly, when the nonwoven fabric 10 is pressed from the 1 st surface side Z1, a cushioning feeling of the sinking of the outer surface fiber layer 1 due to the buckling deformation of the connection portion 3 can be obtained, and a softer touch feeling can be obtained in the portion of the concave portion 7, which is preferable. Further, when the skin surface of the body is overlapped with the concave portion 7, stress concentrates on the connection portion 3 existing at the edge of the concave portion 7, and the connection portion 3 is more likely to be bent and deformed. This makes the cushioning property of the nonwoven fabric 10 more preferable.

In the present embodiment, the plurality of independent concave portions 7 are separated from each other and connected in the Y direction by the 1 st outer surface fiber layer 11. This makes it easy to maintain the shape of the surface Z1 on the 1 st surface side of the nonwoven fabric 10, and is preferable because the shape recovery property after pressing is more excellent. Further, it is preferable that the 1 st outer surface fiber layer 11 and the 2 nd outer surface fiber layer 12 have different heights on the 1 st surface side Z1, because it is possible to suppress the application of the pressing force to the plane direction of the nonwoven fabric 10.

From the viewpoint of effectively exhibiting the above-described function, the area ratio of the recessed portions 7 on the 1 st surface side Z1 of the nonwoven fabric 10 is preferably 5% or more, more preferably 10% or more, and still more preferably 15% or more. From the viewpoint of securing the strength of the nonwoven fabric and the air passage, the area ratio of the concave portions 7 is preferably 90% or less, more preferably 80% or less, and still more preferably 70% or less. Specifically, the area ratio of the concave portion 7 is preferably 5% or more and 90% or less, more preferably 10% or more and 80% or less, and further preferably 15% or more and 70% or less.

(method of measuring the area ratio of concave portion 7)

The area of the concave portion 7 was measured by enlarging the area to a size (10 times or more and 100 times or less) that can be measured while the portion to be measured from the top falls sufficiently in the field of view with a digital microscope (trade name: VHX-1000) manufactured by Keyence corporation, and the ratio was calculated from the whole as an area ratio.

Next, a preferred embodiment of the method for producing the nonwoven fabric 10 of the present embodiment will be described below with reference to fig. 5.

In the method for producing the nonwoven fabric 10 of the present embodiment, the support male member 120 and the support female member 130 for shaping the web 110 before nonwoven forming are used. As shown in fig. 5(a), the fiber web 110 is placed on the support male member 120, and is held and sandwiched by the support female member 130 from above the fiber web 110, thereby performing shaping. The fiber web 110 finally becomes the 1 st nonwoven fabric layer 5.

The male support member 120 has a plurality of protrusions 121 at positions corresponding to the 4 connection portions 3 to be formed so as to surround the recessed portions 7 of the 1 st nonwoven fabric layer 5 and the recessed portion bottom portions 71 of the 2 nd surface side Z2. The

projections

121, 121 of the support male member 120 are formed as recesses 122 corresponding to the positions of the outer surface fiber layer 1 to be shaped into the 1 st surface side Z1 of the 1 st nonwoven fabric layer 5. Thus, the support body male member 120 has a concavo-convex shape, and the protrusions 121 and the recesses 122 are alternately arranged in different directions in a plan view. The bottom 123 of the concave portion 122 of the support male member 120 is configured to be blown through by hot air, and for example, a plurality of holes (not shown) are arranged. As a support for producing the nonwoven fabric 10, the "different direction" is preferably the following direction: the direction coincides with the Y direction (longitudinal direction) and the X direction (width direction) of the nonwoven fabric 10. The Y direction corresponds to the machine flow direction in the present manufacturing method, and the X direction corresponds to the width direction orthogonal to the machine flow direction. The "different directions" are different depending on the uneven structure of the nonwoven fabric of the present invention, and are not limited to the Y direction and the X direction.

The support female member 130 has lattice-shaped protrusions 131 corresponding to the recesses 122 of the support male member 120. The

protrusions

131, 131 of the support female member 130 are formed as recesses 132 corresponding to the protrusions 121 of the support male member 120. Thus, the support female member 130 has a concavo-convex shape, and the protrusions 131 and the recesses 132 are alternately arranged in different directions in a plan view. The bottom 133 of the concave portion 132 of the support female member 130 is configured to be penetrated by hot wind, and has a plurality of holes, for example. The distance between the

protrusions

131, 131 of the support female member 130 is set to be larger than the width of the protrusion 121 of the support male member 120. The distance can be set as appropriate so that the web 110 can be sandwiched between the protrusions 121 of the male member 120 and the protrusions 131 of the female member 130 to appropriately shape the coupling portions 3 in which the fibers are oriented in the thickness direction.

First, in the present embodiment, the web is supplied from a carding machine (not shown) to a shaping device so that the web 110 before welding has reached a certain thickness. The fiber web 110 is a raw material which finally becomes the 1 st nonwoven fabric layer 5.

Next, as shown in fig. 5(a), the fiber web 110 including thermoplastic fibers is arranged on the support male member 120, and the support female member 130 is press-fitted from the fiber web 110 into the support male member 120. At this time, the protrusion 121 of the support male member 120 is fitted into the recess 132 of the support female member 130. The concave portion 122 of the support male member 120 is fitted to the protrusion 131 of the support female member 130. This produces a shape in which the fibers are oriented in the thickness direction and the plane direction.

In this state, as shown in fig. 5(B), the 1 st hot air W1 is blown to the web 110 from the support female member 130 side. That is, the 1 st hot air W1 is blown from the 2 nd surface of the nonwoven fabric 10. This causes the fiber web 110 to be fused to such an extent that the uneven shape of the nonwoven fabric 10 can be maintained. In the fiber web 110, the fibers are extremely slowly fused to each other.

In the fiber web 110, the degree of freedom of movement of the fibers is high unlike in nonwoven fabrics. Therefore, the fibers are easily oriented in the thickness direction (longitudinal direction) on the surface facing in any direction around the protrusions 121 of the support male member 120.

More specifically, when the 1 st hot air W1 is blown toward the web 110 from the support female member 130 side, the connecting portions 3 of the 1 st nonwoven fabric layer 5, in which the fibers are oriented in the thickness direction, are formed between the wall surfaces of the protrusions 121 of the support male member 120 and the wall surfaces of the protrusions 131 of the support female member 130. At this time, the fiber web 110 is not fused at the intersection points of the fibers, and therefore, the fibers have high mobility, and the fiber orientation can be aligned in the blow-through direction of the 1 st hot air W1. More specifically, as shown in fig. 5(B) and 6, the fibers of the fiber web 110 are gathered in the region surrounded by the four wall surfaces of the protrusion 121 of the male support member 120 and the wall surfaces of the protrusion 131 of the female support member 130 surrounding the same. That is, the fibers are aligned in the blow-through direction of the 1 st hot air W1 regardless of the orientation of the wall surface 131A of the protrusion 121 along the machine flow direction (Y direction) or the wall surface 131B along the width direction (X direction). This allows the fibers in the connecting portions 3 of the nonwoven fabric 10 to be oriented in the thickness direction.

Further, between the top of the protrusion 121 and the bottom of the recess 132, the blow-through of the 1 st hot air W1 is suppressed, and the fibers are fused in the planar direction. Thereby, a fiber layer corresponding to the outer surface fiber layer 2 of the 2 nd surface side Z2 is formed. Further, between the bottom of the recess 122 and the top of the protrusion 131, the fibers are oriented in the planar direction. Since the protrusions 131 block the hot air, the amount of fusion in the formed fiber layer is small, and a smooth fiber layer can be obtained. Thereby, a fiber layer corresponding to the outer surface fiber layer 1 of the 1 st surface side Z1 is formed. The shape of the coupling portion oriented in the thickness direction is also maintained.

Note that the arrows in the drawings schematically show the flow of the 1 st hot air W1.

The temperature of the 1 st hot air W1 is set to a temperature at which the thermoplastic fibers can maintain the longitudinally oriented shape. Considering a general fiber material used for such products, the melting point of the thermoplastic fibers constituting the fiber web 110 is preferably higher than 0 ℃ or higher and 70 ℃ or lower, and more preferably higher than 5 ℃ or higher and 50 ℃ or lower.

From the viewpoint of effective welding, the wind speed of the first hot wind W1 is preferably 2m/s or more, and more preferably 3m/s or more. In addition, the wind speed of the first hot wind W1 is preferably 100m/s or less, and more preferably 80m/s or less, from the viewpoint of making the apparatus compact.

In this way, the fiber web 110 is pseudo-welded and held in the uneven shape (hereinafter, the fiber web 110 is referred to as an uneven fiber web 111).

The height of the projections 121 of the support male member 120 and the height of the projections 131 of the support male member 130 are appropriately determined depending on the apparent thickness of the nonwoven fabric 10 to be produced. For example, it is preferably 2mm or more, more preferably 3mm or more, further preferably 5mm or more, and further preferably 15mm or less, more preferably 10mm or less, further preferably 9 or less. Specifically, it is preferably 2mm or more and 15mm, more preferably 3mm or more and 10mm or less, and further preferably 5mm or more and 9mm or less.

Next, as shown in fig. 5(C), the support female member 130 is removed, and the other web 140 serving as the 2 nd nonwoven layer 6 is directly placed on the exposed surface (the surface opposite to the support male member 120) of the uneven web 111 in a state where the uneven web 111 is along the support male member 120. Next, the 2 nd hot air W2 at a temperature at which the fibers of the uneven fiber web 111 and the fiber web 140 can be appropriately welded is blown to further weld the fibers to each other. In this case, similarly to the first hot air W1, the 2 nd hot air W2 is blown to the uneven fiber web 111 and the fiber web 140 from the side to be the 2 nd surface of the nonwoven fabric 10. Considering a general fiber material used for such products, the temperature of the 2 nd hot air W2 is preferably 0 ℃ to 70 ℃ higher than the melting point of the thermoplastic fibers constituting the fiber web 110, and more preferably 5 ℃ to 50 ℃.

The speed of the 2 nd hot wind W2 is preferably 2m/s or more, more preferably 3m/s or more depending on the height of the projections 121 of the support male members 120. This allows the fibers to be sufficiently thermally conducted and welded to each other, and the uneven shape can be sufficiently fixed. The wind speed of the 2 nd hot wind W2 is preferably 100m/s or less, and more preferably 80m/s or less. This can suppress excessive heat conduction to the fibers, and can improve the hand of the nonwoven fabric 10.

By reducing the surface roughness of the female support member, the step of blowing the first hot air W1 can be omitted. By reducing the surface roughness, the support female material can be detached in the blowing step of the 2 nd hot wind W2 without the fibers that are not welded intertwining with each other. In other words, after the web is produced, the male member and the female member are fitted to each other, and the female member is directly removed and treated with hot air W2. This makes the processing easier.

As the thermoplastic fiber, a fiber generally used as a raw material of a nonwoven fabric can be used without particular limitation. For example, the fiber may be a fiber composed of a single resin component, or a composite fiber composed of a plurality of resin components. Examples of the composite fiber include a core-sheath type and a side-by-side type.

In the case of using a composite fiber containing a low-melting-point component and a high-melting-point component (for example, a core-sheath composite fiber in which the sheath is the low-melting-point component and the core is the high-melting-point component) as the thermoplastic fiber, the temperature of the hot air blown to the fiber web 110, the uneven fiber web 111, and the fiber web 140 is preferably equal to or higher than the melting point of the low-melting-point component and lower than the melting point of the high-melting-point component. More preferably, the temperature is a temperature which is not less than the melting point of the low-melting component and is 10 ℃ lower than the melting point of the high-melting component, and still more preferably a temperature which is not less than 5 ℃ higher than the melting point of the low-melting component and is not less than 20 ℃ lower than the melting point of the high-melting component. In addition, from the viewpoint of elasticity, in the core-sheath type composite fiber, the more the core as a high melting point component, the higher the elasticity. Therefore, the core component is preferably large in terms of the cross-sectional area ratio.

As described above, the nonwoven fabric 10 is produced. The fibers of the web 110 are uniformly oriented in the thickness direction between the protrusions 122 of the male support member 120 and the protrusions 131 of the female support member 130, thereby forming the connection portions 3 of the 1 st nonwoven fabric layer 5. At this time, the coupling portion 3 in which the fibers are oriented in the thickness direction (longitudinal direction) is formed on the surface facing in any direction around the protrusion 121. This forms the recessed portions 7 surrounded by the four connecting portions 3 included in the 1 st nonwoven fabric layer 5. Further, the recess bottom 71 of the 1 st nonwoven fabric layer 5 is formed between the top of the protrusion 121 and the bottom of the recess 132. Further, the outer surface fiber layer 1 of the 1 st surface side Z1 of the 1 st nonwoven fabric layer 5 in which the fibers are oriented in the planar direction is formed between the bottom of the recess 122 and the top of the protrusion 131. The fiber web 140 is welded to each other while being kept flat, thereby forming the second outer-surface fiber layer 2 including the 2 nd nonwoven fabric layer 6. This forms a hollow portion 4 surrounded by the outer surface fiber layer 1 of the 1 st nonwoven fabric layer 5, the connecting portion 3, and the 2 nd nonwoven fabric layer 6 (outer surface fiber layer 2).

In the obtained nonwoven fabric 10, the lower surface in fig. 5(C) is the 1 st surface side Z1, and the opposite surface is the 2 nd surface side Z2. That is, the 1 st surface Z1 of the nonwoven fabric 10 is the side on which the support male member 120 is disposed, and the 2 nd surface Z2 is the side on which the first hot air W1 and the second hot air W2 are blown. Therefore, the fiber amount of the outer surface fiber layer 2 of the 2 nd surface side Z2 is smaller than the fiber amount of the outer surface fiber layer 1 of the 1 st surface side Z1 due to the difference in the blowing amount of the first hot wind W1. The fusion points between the fibers of the outer surface fiber layer 2 on the 2 nd surface side Z2 are larger than those of the outer surface fiber layer 1 on the 1 st surface side Z1. Further, due to the difference in heat, the surface of the outer surface fiber layer 1 on the 1 st surface side Z1 has less roughness and a good texture as compared with the surface of the outer surface fiber layer 2 on the 2 nd surface side Z2. Even if the step of blowing the first hot wind W1 is omitted, the same effect can be obtained by utilizing the distance from the second hot wind W2. Further, by fitting the support, the fibers on the support female member 130 side (the fibers of the outer surface fiber layer 2 to be the 2 nd surface side Z2 in the nonwoven fabric 10) are stretched and directed toward the support male member 120. Therefore, the amount of the fibers in the outer surface fiber layer 2 formed on the 2 nd surface side Z2 at the top of the projection 121 of the support male member 120 is smaller than that in the outer surface fiber layer 1 formed on the 1 st surface side Z1 at the bottom of the recess 122 of the support male member 120.

In the manufacturing method of the present embodiment, the thickness of the nonwoven fabric 10 is appropriately determined according to the heights of the protrusions 121 of the support male members 120 and the protrusions 131 of the support female members 130. For example, if the height of the protrusions is increased, the apparent thickness of the nonwoven fabric 10 becomes thicker, and if the height of the protrusions is decreased, the apparent thickness of the nonwoven fabric 10 becomes thinner. On the other hand, if the wind speed is increased, the apparent thickness of the nonwoven fabric 10 becomes large, and if the wind speed is decreased, the apparent thickness of the nonwoven fabric 10 becomes small. In addition, if the height of the protrusions is increased, the fiber density of the nonwoven fabric 10 is decreased, and if the height of the protrusions is decreased, the fiber density of the nonwoven fabric 10 is increased. On the other hand, if the wind speed is increased, the fiber density of the nonwoven fabric 10 decreases, and if the wind speed is decreased, the fiber density of the nonwoven fabric 10 increases.

The nonwoven fabric of the present invention can be used for various purposes. For example, the sheet can be suitably used as a topsheet for absorbent articles such as disposable diapers, sanitary napkins, panty liners, and urine pads for human use or infants. Further, since the sheet has excellent deformation characteristics under a pressing force, the sheet can be used as a sub-layer interposed between a topsheet and an absorbent body of a diaper, a sanitary product, or the like, or a cover sheet (core wrap sheet) of an absorbent body, or the like. Further, the form of the topsheet, the gather, the outer sheet, and the side flaps used as the absorbent article can be exemplified. Further, the present invention may be used as a cover sheet for a hip wiping sheet, a cleaning sheet, a filter, or a heating device.

The present invention also discloses the following nonwoven fabric according to the above embodiment.

<1> a nonwoven fabric having thermoplastic fibers and having a 1 st surface side and a 2 nd surface side, the 2 nd surface side being the opposite surface side to the 1 st surface side,

the nonwoven fabric has the 1 st-surface-side outer surface fiber layer, the 2 nd-surface-side outer surface fiber layer, a plurality of connecting portions between the 1 st-surface-side outer surface fiber layer and the 2 nd-surface-side outer surface fiber layer, and a hollow portion between the connecting portions, the hollow portion being continuous in the planar direction of the nonwoven fabric.

<2> the nonwoven fabric according to <1>, wherein the hollow portion is continuous along a plurality of different directions intersecting each other in a plan view of the nonwoven fabric.

<3>According to the above<2>In the nonwoven fabric, a flow path area of an air passage formed by continuous hollow portions in a longitudinal direction of the nonwoven fabric among a plurality of different directions intersecting with each other in a plan view of the nonwoven fabric is 1.5mm per flow path in a cross section²Above and 7.8mm²Preferably 2.3mm or less²Above, more preferably 3mm²The above, preferably 7mm²Less than, more preferably 6.2mm²The following.

<4>According to the above<2>Or<3>In the nonwoven fabric, in a width direction of the nonwoven fabric in a plurality of different directions intersecting with each other in a plan view of the nonwoven fabric, a flow path area of each flow path in a cross section of the nonwoven fabric is 2.3mm with respect to a flow path area of an air passage formed by continuous hollow portions²Above and 11.6mm²Preferably 3.5mm or less²Above, more preferably 4.5mm²The above, preferably 10.5mm²Less than, more preferably 9.3mm²The following.

<5> the nonwoven fabric according to <4>, wherein a flow passage area of an air passage in which the hollow portions are continuous in the longitudinal direction is smaller than a flow passage area of an air passage in which the hollow portions are continuous in the width direction.

<6> the nonwoven fabric according to any one of <1> to <5>, wherein the fibers of the connecting portion are oriented in a thickness direction of the nonwoven fabric.

<7> the nonwoven fabric according to <6>, wherein the longitudinal orientation ratio of the fibers of the connecting portion is 60% or more and 90% or less, preferably 63% or more, more preferably 65% or more, and preferably 85% or less, more preferably 80% or less.

<8> the nonwoven fabric according to <6>, wherein the longitudinal orientation ratio of the fibers of the connecting portion is 65% or more and 80% or less.

<9> the nonwoven fabric according to any one of <1> to <8>, wherein the connecting portion has a wall surface having a height in a thickness direction of the nonwoven fabric and a width in a planar direction of the nonwoven fabric extending in an extending direction of the outer surface fiber layer on the 1 st surface side and the outer surface fiber layer on the 2 nd surface side, and the wall surface is arranged along a plurality of different directions intersecting with each other in a plan view of the nonwoven fabric.

<10> the nonwoven fabric according to any one of <1> to <9>, which has an uneven surface on the 1 st surface side of the nonwoven fabric.

<11> the nonwoven fabric according to <10>, wherein there are 2 types of the nonwoven fabric, and the outer surface fiber layers on the 1 st surface side have lengths extending in different directions intersecting each other in a plan view of the nonwoven fabric.

<12> the nonwoven fabric according to <11>, wherein one of the 2 types of outer surface fiber layers on the 1 st surface side continuously extends in a longitudinal direction in a plan view of the nonwoven fabric, and a plurality of the outer surface fiber layers are arranged at intervals in a width direction orthogonal to the longitudinal direction.

<13> the nonwoven fabric according to <12>, wherein the other outer surface fiber layer of the 2 outer surface fiber layers on the 1 st surface side is arranged so as to extend in the width direction in a plan view of the nonwoven fabric and connect the one outer surface fiber layers.

<14> the nonwoven fabric according to <13>, wherein the position of the one outer surface fiber layer on the first surface side of the nonwoven fabric is set lower than that of the other outer surface fiber layer on the 1 st surface side.

<15> the nonwoven fabric according to <13> or <14>, wherein a width of the other outer surface fiber layer in the longitudinal direction is smaller than a width of the one outer surface fiber layer in the width direction on the 1 st surface side.

<16> the nonwoven fabric according to any one of <10> to <15>, wherein the connecting portion has a wall surface having a height in a thickness direction of the nonwoven fabric and a width in a plane direction of the nonwoven fabric extending in an extending direction of the outer surface fiber layer on the 1 st surface side and the outer surface fiber layer on the 2 nd surface side,

the concave-convex surface is provided with a concave portion surrounded by the wall surface and opened to the 1 st surface side.

<17> the nonwoven fabric according to <16>, wherein the recessed portion has a recessed portion bottom portion on the 2 nd surface side,

the recessed portion bottom portion covers the partition space of the outer surface fiber layer on the 1 st surface side on the 2 nd surface side, and is formed in a plurality of rows spaced from each other along a longitudinal direction of the nonwoven fabric, which is an extending direction of the outer surface fiber layer on the 1 st surface side.

<18> the nonwoven fabric according to <17>, wherein a plurality of longitudinal rows formed at the bottom of the recess are arranged so as to be spaced apart from each other in a width direction orthogonal to the longitudinal direction.

<19> the nonwoven fabric according to any one of <16> to <18>, wherein the recessed portions are independent from each other and do not communicate with each other.

<20> the nonwoven fabric according to any one of <1> to <19>, wherein the outer surface fiber layer on the 1 st surface side and the outer surface fiber layer on the 2 nd surface side cover the front and back surfaces of the hollow portion.

<21> the nonwoven fabric according to any one of <1> to <20>, wherein the hollow portion is a space defined by the connecting portion inside the nonwoven fabric.

<22> the nonwoven fabric according to any one of <1> to <21>, wherein the hollow portion is covered on the front and back surfaces with the 1 st surface side outer surface fiber layer and the 2 nd surface side outer surface fiber layer, and the hollow portion is not perforated in the thickness direction.

<23>According to the above<1>～<22>The nonwoven fabric of any of the above, whereinThe hollow part is a hollow part with the fiber amount of 20 pieces/mm²Hereinafter, a space in which no fiber is disposed is preferable.

<24> the nonwoven fabric according to any one of <1> to <23>, wherein the hollow portion continuously forms an air passage along a plurality of different directions intersecting with each other in a plan view of the nonwoven fabric,

the air passage reaches the end of the nonwoven fabric.

<25> the nonwoven fabric according to any one of <1> to <24>, wherein the nonwoven fabric has an apparent thickness of 2mm or more and 10mm or less, preferably 3mm or more, more preferably 4mm or more, and preferably 9mm or less, more preferably 8mm or less.

<26> the nonwoven fabric according to any one of <1> to <24>, wherein the nonwoven fabric has an apparent thickness of 4mm to 8 mm.

<27>According to the above<1>～<26>The nonwoven fabric of any one of the above, wherein the weight per unit area of the whole nonwoven fabric is 8g/m²Above and 80g/m²Hereinafter, it is preferably 70g/m²Below, more preferably 60g/m²Hereinafter, it is preferably 10g/m²More preferably 15g/m or more²The above.

<28> the nonwoven fabric according to any one of <1> to <27>, wherein the nonwoven fabric is a laminate of a 1 st nonwoven fabric layer and a 2 nd nonwoven fabric layer, the 1 st nonwoven fabric layer has the 1 st surface side outer surface fiber layer and the connecting portion, and the 2 nd nonwoven fabric layer forms the 2 nd surface side outer surface fiber layer.

<29> the nonwoven fabric according to <28>, wherein the 1 st nonwoven fabric layer has a recess opened to the 1 st surface side, and the recess and the outer surface fiber layer on the 1 st surface side provide a concave-convex surface on the 1 st surface side.

<30> the nonwoven fabric according to <28> or <29>, wherein the 2 nd nonwoven fabric has a substantially flat shape and is continuously arranged in a planar shape on the 2 nd surface side as a whole.

<31> the nonwoven fabric according to any one of <1> to <30>, wherein fibers are oriented in a planar direction in the outer surface fiber layer on the 1 st surface side and the outer surface fiber layer on the 2 nd surface side.

<32> an absorbent article comprising the nonwoven fabric according to any one of <1> to <31 >.

<33> an absorbent article comprising, as a topsheet, the nonwoven fabric of any one of <1> to <31> above, such that a surface opposite to a surface that comes into contact with hot air during production faces the skin surface side of a wearer as one surface side.

<34> an absorbent article comprising, as a topsheet, the nonwoven fabric of any one of <1> to <31> above, such that a surface which is brought into contact with hot air during production faces the skin surface side of a wearer as the other surface side.

<35> a method for producing a nonwoven fabric, comprising: and a step of placing a web on a support male member having a plurality of protrusions and a plurality of recesses arranged between the plurality of protrusions, and pressing the web with a support female member having recesses and protrusions corresponding to the protrusions and recesses of the support male member to shape the web.

<36> the method for producing a nonwoven fabric according to <35>, wherein the bottom portions of the concave portions of the support male member and the support female member are configured to be penetrated by hot air, and the method comprises: and a step of blowing hot air in a state where the male support member and the female support member are fitted with the fiber web therebetween.

<37> the method for producing a nonwoven fabric according to <35> or <36>, wherein the support female member is detached,

placing another web on a surface of the web opposite to the male support member in a state where the web is attached to the male support member,

the hot air is blown to the two fiber webs to further fuse the fibers to each other.

Examples

The present invention will be described in more detail with reference to examples, but the present invention is not to be construed as being limited thereto. In the present example, "part(s)" and "%" are based on mass unless otherwise specified.

(example 1)

The nonwoven fabric shown in fig. 1 was produced by a hot air production method including the steps shown in fig. 5 using a core-sheath thermoplastic fiber (polyethylene terephthalate (PET)/Polyethylene (PE) ═ 5:5) having a fiber diameter of 1.2 dtex. This was used as a nonwoven fabric sample of example 1. The blowing treatment with the first hot wind W1 was performed at a temperature of 160 ℃, a wind speed of 54m/s, and a blowing time of 3 seconds. The second hot air was blown at a temperature of 160 ℃ and a wind speed of 6m/s for a blowing time of 3 seconds.

The nonwoven fabric sample S1 of example 1 had the meshed hollow portions 4 shown in fig. 1. Specifically, the first hollow portion 41 is continuous in the Y direction which is the longitudinal direction of the nonwoven fabric sample S1, and the second hollow portion 42 is continuous in the X direction which is the width direction orthogonal to the longitudinal direction of the nonwoven fabric sample S1. The first hollow portion 41 and the second hollow portion 42 are connected at the intersecting portion, and the hollow portions 4 are connected in a mesh shape as the whole nonwoven fabric sample S1.

The nonwoven fabric sample of example 1 was provided with the connecting portion 3 defined above.

The nonwoven fabric sample of example 1 further had a concave portion 7 opened on the 1 st plane Z1 side.

(example 2)

The nonwoven fabric shown in FIG. 1 was produced by a hot air production method including the step shown in FIG. 5 using a thermoplastic fiber having a fiber diameter of 2.9 dtex. This was used as a nonwoven fabric sample of example 2. The blowing treatment with the first hot wind W1 was performed at a temperature of 160 ℃, a wind speed of 54m/s, and a blowing time of 3 s. The blowing treatment with the second hot air was performed at a temperature of 160 ℃, a wind speed of 6m/s, and a blowing time of 3 s.

In the nonwoven fabric sample of example 2, the first hollow portion 41 and the second hollow portion 42 were connected in a mesh shape, as in example 1.

Comparative example

A flat nonwoven fabric having uneven shape was produced without hot air forming by using a thermoplastic fiber having a fiber diameter of 1.2dtex, and this was used as a nonwoven fabric sample of comparative example.

(reference example)

The uneven nonwoven fabric having the shape shown in fig. 1 of patent document 1 is produced by a hot air production method including the production step described in paragraph [0031] of the specification of the document using thermoplastic fibers having a fiber diameter of 1.2 dtex. This was used as a nonwoven fabric sample of the reference example. The blowing treatment with the first hot wind W1 was performed at a temperature of 160 ℃, a wind speed of 54m/s, and a blowing time of 3 seconds. The second hot air was blown at a temperature of 160 ℃ and a wind speed of 6m/s for a blowing time of 3 seconds.

In the nonwoven fabric sample of the reference example, the first protrusions on the 1 st surface side and the second protrusions on the 2 nd surface side are each in the shape of a truncated cone with a rounded top or a hemisphere. As a result of measurement of the top portion in accordance with the above (method of measuring the longitudinal orientation ratio of the fibers in the connecting portion 3), the longitudinal orientation ratio of the fibers at the top portion was 35%, and the fibers were radially oriented in the thickness direction from the top portion. The nonwoven fabric sample of the reference example did not have the hollow portions as in examples 1 and 2.

The following tests were carried out on the above examples, comparative examples and reference examples.

(transverse air permeability test)

Each nonwoven fabric sample was sandwiched between a square first acrylic sheet (size: 50 mm. times.50 mm. times.3 mm) having a cylindrical opening of 10mm on one side at the center and a second acrylic sheet identical to the first acrylic sheet except that no opening was provided, with the 1 st surface Z1 being on the side of the first acrylic sheet. A Gerley tester was attached to the opening of the first acrylic plate, and the time (seconds) required for air at a scale of 0 to 100mL to pass through the edge of the outer tube was measured using a stopwatch according to the JISP8117 test method, and the air permeability per 1 second was calculated. The measurement was performed 3 times, and the average was taken as the air permeability of the sample.

The cross-direction air permeability test can evaluate the air permeability resistance when air flows through the thickness of a nonwoven fabric sample. In this evaluation, the higher the air permeability, the better the air permeability within the thickness of the nonwoven fabric.

[ Table 1]

As shown in table 1, examples 1 and 2 had an air permeability of 3 times or more as compared with the comparative example, and were found to have excellent air permeability.

Although the present invention has been described in connection with the embodiments and examples thereof, it is not intended to be limited to the details shown, unless otherwise specified by the inventors, but rather should be construed broadly within the spirit and scope of the invention as defined in the appended claims.

The present application claims priority from the patent application japanese patent application No. 2017-168001 filed in japan at 31/8/2017, which is incorporated herein by reference as part of the description of the present specification.

Description of the reference numerals

1 outer surface fiber layer on the 1 st surface side

11 st outer surface fiber layer

12 nd 2 nd outer surface fiber layer

2 outer surface fiber layer of 2 nd face side

3 connecting part

31 st connecting part

32 nd 2 nd connecting part

39 end of the connecting part

4 hollow part

41 st hollow part 1

42 nd 2 nd hollow part

41A, 42A ventilation path

5 th 1 nonwoven Fabric layer

6 nd 2 non-woven fabrics layer

7 concave part

71 bottom of recess

10 nonwoven fabric

Z1 face side 1

Z2 side of 2 nd surface

Claims

1. A nonwoven fabric having thermoplastic fibers and having a 1 st surface side and a 2 nd surface side, the 2 nd surface side being the opposite side of the 1 st surface side,

2. The nonwoven fabric according to claim 1, wherein the hollow portion is continuous along a plurality of different directions intersecting in a plan view of the nonwoven fabric.

3. The nonwoven fabric according to claim 2, wherein a flow path area of each flow path in a cross section of a flow path of the air passage formed by the hollow portion being continuous in a longitudinal direction of the nonwoven fabric among a plurality of different directions intersecting with each other in a plan view of the nonwoven fabric is 1.5mm²Above and 7.8mm²Preferably 2.3mm or less²Above, more preferably 3mm²The above, preferably 7mm²Less than, more preferably 6.2mm²The following.

4. The nonwoven fabric according to claim 2 or 3, wherein, with respect to the flow path area of the air passage in which the hollow portion is continuous in the width direction of the nonwoven fabric among a plurality of different directions intersecting in a plan view of the nonwoven fabric, the flow path area of each flow path in a cross section is 2.3mm²Above and 11.6mm²Preferably 3.5mm or less²Above, more preferably 4.5mm²The above, preferably 10.5mm²Less than, more preferably 9.3mm²The following.

5. The nonwoven fabric according to claim 4, wherein a flow path area of an air passage in which the hollow portions are continuous in the longitudinal direction is smaller than a flow path area of an air passage in which the hollow portions are continuous in the width direction.

6. The nonwoven fabric according to any one of claims 1 to 5, wherein the fibers of the connecting portions are oriented in the thickness direction of the nonwoven fabric.

7. The nonwoven fabric according to claim 6, wherein the longitudinal orientation ratio of the fibers of the connecting portion is 60% or more and 90% or less, preferably 63% or more, more preferably 65% or more, and preferably 85% or less, more preferably 80% or less.

8. The nonwoven fabric according to claim 6, wherein the longitudinal orientation ratio of the fibers of the connecting portion is 65% or more and 80% or less.

9. The nonwoven fabric according to any one of claims 1 to 8, wherein the connecting portion has wall surfaces that have a height in a thickness direction of the nonwoven fabric and a width in a planar direction of the nonwoven fabric extending in an extending direction of the outer surface fiber layer on the 1 st surface side and the outer surface fiber layer on the 2 nd surface side, and the wall surfaces are arranged along a plurality of different directions intersecting with each other in a plan view of the nonwoven fabric.

10. The nonwoven fabric according to any one of claims 1 to 9, which has a concave-convex surface on the 1 st surface side of the nonwoven fabric.

11. The nonwoven fabric according to claim 10, wherein there are 2 types of the outer surface fiber layers on the 1 st surface side of the nonwoven fabric, and the outer surface fiber layers have lengths extending in different directions intersecting with each other in a plan view of the nonwoven fabric.

12. The nonwoven fabric according to claim 11, wherein one of the 2 types of outer surface fiber layers on the 1 st surface side continuously extends in a longitudinal direction in a plan view of the nonwoven fabric, and a plurality of the outer surface fiber layers are arranged at intervals from each other in a width direction orthogonal to the longitudinal direction.

13. The nonwoven fabric according to claim 12, wherein the other outer surface fiber layer of the 2 outer surface fiber layers on the 1 st surface side is arranged so as to extend in the width direction in a plan view of the nonwoven fabric and connect the one outer surface fiber layers.

14. The nonwoven fabric according to claim 13, wherein the position of the one outer surface fiber layer on the first surface side of the nonwoven fabric is set lower than the position of the other outer surface fiber layer on the first surface side of the nonwoven fabric on the 1 st surface side.

15. The nonwoven fabric according to claim 13 or 14, wherein the width in the length direction of the other outer surface fiber layer is smaller than the width in the width direction of the one outer surface fiber layer on the 1 st surface side.

16. The nonwoven fabric according to any one of claims 10 to 15, wherein the connecting portion has a wall surface having a height in a thickness direction of the nonwoven fabric and a width in a plane direction of the nonwoven fabric extending in an extending direction of the outer surface fiber layer on the 1 st surface side and the outer surface fiber layer on the 2 nd surface side,

17. The nonwoven fabric according to claim 16, wherein the recessed portion has a recessed portion bottom portion on the 2 nd surface side,

the recessed portion bottom portions cover the partition spaces of the outer surface fiber layer on the 1 st surface side on the 2 nd surface side, and are arranged in a plurality of rows spaced apart from each other along a longitudinal direction of the nonwoven fabric, which is an extending direction of the outer surface fiber layer on the 1 st surface side.

18. The nonwoven fabric according to claim 17, wherein a plurality of longitudinal rows formed at the bottom of the recess are arranged at intervals in a width direction orthogonal to the longitudinal direction.

19. The nonwoven fabric according to any of claims 16-18, wherein the depressions are independent from each other and do not communicate with each other.

20. The nonwoven fabric according to any one of claims 1 to 19, wherein the 1 st surface side outer surface fiber layer and the 2 nd surface side outer surface fiber layer cover the front and back of the hollow portion.

21. The nonwoven fabric according to any one of claims 1 to 20, wherein the hollow portion is a space defined by the connecting portion inside the nonwoven fabric.

22. The nonwoven fabric according to any one of claims 1 to 21, wherein the hollow portion is covered with the 1 st surface-side outer surface fiber layer and the 2 nd surface-side outer surface fiber layer on the front and back sides, and the hollow portion is not perforated in the thickness direction.

23. The nonwoven fabric according to any one of claims 1 to 22, wherein the hollow portion has a fiber amount of 20 fibers/mm²Hereinafter, a space in which no fiber is disposed is preferable.

24. The nonwoven fabric according to any one of claims 1 to 23, wherein the hollow portion is continuous along a plurality of different directions intersecting in a plan view of the nonwoven fabric to form an air passage,

the air passage reaches the end of the nonwoven fabric.

25. The nonwoven fabric according to any one of claims 1 to 24, wherein the apparent thickness of the nonwoven fabric is 2mm or more and 10mm or less, preferably 3mm or more, more preferably 4mm or more, and further preferably 9mm or less, more preferably 8mm or less.

26. The nonwoven fabric according to any one of claims 1 to 24, wherein the apparent thickness of the nonwoven fabric is 4mm or more and 8mm or less.

27. The nonwoven fabric according to any one of claims 1 to 26, wherein the overall basis weight of the nonwoven fabric is 8g/m²Above and 80g/m²Hereinafter, it is preferably 70g/m²Below, more preferably 60g/m²Hereinafter, it is preferably 10g/m²More preferably 15g/m or more²The above.

28. The nonwoven fabric according to any one of claims 1 to 27, wherein the nonwoven fabric is a laminate of a 1 st nonwoven fabric layer and a 2 nd nonwoven fabric layer, the 1 st nonwoven fabric layer has the 1 st-surface-side outer surface fiber layer and the connecting portion, and the 2 nd nonwoven fabric layer forms the 2 nd-surface-side outer surface fiber layer.

29. The nonwoven fabric according to claim 28, wherein the 1 st nonwoven fabric layer has a recess that opens to the 1 st surface side, and has a concave-convex surface on the 1 st surface side based on the recess and the outer surface fiber layer on the 1 st surface side.

30. The nonwoven fabric according to claim 28 or 29, wherein the 2 nd nonwoven fabric has a substantially flat shape and is continuously arranged in a planar shape on the 2 nd surface side as a whole.

31. The nonwoven fabric according to any one of claims 1 to 30, wherein in the 1 st surface-side outer surface fiber layer and the 2 nd surface-side outer surface fiber layer, fibers are oriented in a planar direction.

32. An absorbent article having the nonwoven fabric according to any one of claims 1 to 31.

33. An absorbent article comprising, as a topsheet, the nonwoven fabric according to any one of claims 1 to 31 so that a surface opposite to a surface that is exposed to hot air during production faces the skin surface of a wearer as one surface side.

34. An absorbent article comprising, as a topsheet, the nonwoven fabric according to any one of claims 1 to 31 such that a surface that is exposed to hot air during production faces the skin surface side of a wearer as the other surface side.

35. A method for producing a nonwoven fabric, comprising: and a step of placing a web on a support male member having a plurality of protrusions and a plurality of recesses arranged between the plurality of protrusions, and pressing the web from above with a support female member having recesses and protrusions corresponding to the protrusions and recesses of the support male member to shape the web.

36. The method for producing a nonwoven fabric according to claim 35, wherein the bottom of the concave portions of the support male member and the support female member is configured to be penetrated by hot air, and the method comprises: and a step of blowing hot air in a state where the support male member and the support female member are fitted with the fiber web therebetween.

37. The method for producing a nonwoven fabric according to claim 35 or 36, wherein the support female material is removed,