WO2019073643A1

WO2019073643A1 - Nonwoven fabric for liquid-permeable sheet of absorbent article and nonwoven fabric roll

Info

Publication number: WO2019073643A1
Application number: PCT/JP2018/024928
Authority: WO
Inventors: 匡志宇田; 弘光田房
Original assignee: ユニ・チャーム株式会社
Priority date: 2017-10-11
Filing date: 2018-06-29
Publication date: 2019-04-18
Also published as: JP6429971B1; TW201922193A; TWI763882B; JP2019069089A

Abstract

Provided is a nonwoven fabric for a liquid-permeable sheet of an absorbent article having good skin feel while not being susceptible to the problem of the cotton inside falling out and not tending to create a damp sensation against a wearer's skin. This nonwoven fabric (20) is constituted by a first fiber layer (21) including cotton (C) and thermoplastic resin fibers (F1) and a second fiber layer (22) including thermoplastic resin fibers (F2) but not cotton, comprises a plurality of protrusions (23) and a plurality of recesses (24), and has a protrusion region (23A) that extends from a second surface (2b) of each of the protrusions (23) to a first surface (2a) thereof in the thickness direction and a recess region (24A) that extends from a second surface (2b) of each of the recesses (24) to a first surface (2a) thereof in the thickness direction. The cotton (C) content in the first fiber layer (21) is smaller in the recess region (24A) than in the protrusion region (23A).

Description

Nonwoven fabric and nonwoven fabric roll for liquid permeable sheet of absorbent article

The present invention relates to a non-woven fabric used as a liquid-permeable sheet of an absorbent article such as a disposable diaper and a sanitary napkin, and a non-woven fabric roll in which the non-woven fabric is wound in a roll.

In absorbent articles such as disposable diapers and sanitary napkins, use a non-woven fabric containing cotton, which is a natural fiber, as a material for a liquid-permeable sheet such as a surface sheet, in order to obtain a sense of security by natural materials. Is being considered.

For example, Patent Document 1 includes a hydrophobic fiber and a hydrophilic fiber such as cotton shorter than the hydrophobic fiber, wherein the hydrophobic fiber is heat-sealed to each other, and at least a portion of the hydrophilic fiber Discloses a surface layer (non-woven fabric) of an absorbent article, in which the particles are dispersed in a sheet as an aggregate, and at least a part of the hydrophilic fibers of the aggregate are fused to the surface of the hydrophobic fiber There is. The surface layer disclosed in the patent document 1 makes it easy for the large amount of liquid to permeate to the absorbent layer, and makes it easy for the small amount of liquid to be retained in the surface layer, to the skin of the wearer. It is said that an absorbent article which is hard to give a moist feeling and which has a good wearing feeling can be provided.

JP-A-2002-651

However, for the non-woven fabric such as the surface layer disclosed in this patent document 1, that is, a non-woven fabric in which cotton is dispersed in the surface direction, for the purpose of obtaining a good touch etc. When the structure is formed, in the relatively thin concave portion, the distance from the inside to the outside of the non-woven fabric is short, so the cotton dispersed inside the non-woven fabric is the outside of the non-woven fabric due to physical load such as friction and vibration. When the cotton dispersed in the non-woven fabric absorbs and holds excrement fluid such as urine excreted from the wearer, the excrement fluid held by the cotton is the body of the wearer There is a possibility that the pressure on the surface of the non-woven fabric tends to exude due to pressure or the like (that is, rewet tends to occur), and as a result, the wearer's skin may feel moist.

Therefore, an object of the present invention is to provide a non-woven fabric for a liquid-permeable sheet of an absorbent article, which has a good touch, is hard to come off the internal cotton, and hardly gives a moist feeling to the wearer's skin. .

One embodiment (embodiment 1) of the present invention is a nonwoven fabric for a liquid-permeable sheet of an absorbent article, having a first surface and a second surface facing each other in a thickness direction, wherein the nonwoven fabric is the liquid-permeable material The first surface to be the non-skin-facing surface of the sheet is formed, the first fiber layer containing cotton and thermoplastic resin fibers, and the second surface to be the skin-facing surface of the liquid-permeable sheet are formed. A plurality of convex portions which are constituted by a second fiber layer containing a plastic resin fiber and not containing cotton, and projecting in a direction from the first surface to the second surface, and the first surface from the second surface A plurality of recesses recessed in a direction toward the surface, and the non-woven fabric is provided with a protrusion region extending in the thickness direction from the second surface of the protrusion to the first surface; And a recessed area extending in the thickness direction from the second surface to the first surface Te, the recessed area, the content of cotton in the first fibrous layer is smaller than the convex region, which is the non-woven fabric.

The non-woven fabric of the present embodiment is constituted by a first fiber layer containing cotton and a thermoplastic resin fiber, and a second fiber layer containing a thermoplastic resin fiber and not containing cotton, and the plurality of convex portions and a plurality of the above When the nonwoven fabric of the present embodiment is used for a liquid-permeable sheet (for example, a surface sheet etc.) of an absorbent article while exhibiting a good touch by the plurality of projections and depressions. (C) by including cotton in the first fiber layer located away from the skin-facing surface facing the wearer's skin (ie, the second surface of the non-woven fabric) (in other words, the first fiber including cotton) By the second fiber layer interposing on the skin facing surface side of the layer), the entire cotton falls out from the skin facing surface side of the liquid-permeable sheet (that is, the second surface side of the non-woven fabric) to the outside Difficult and also hydrophilic Even if the cotton is held by absorbing the liquid waste such as urine discharged from the wearer, the liquid waste is not easily exudation into the liquid-permeable sheet of skin-facing surface.
And the nonwoven fabric of this mode is extended in the thickness direction from the convex part field which extends in the thickness direction from the 2nd surface to the 1st surface of the above-mentioned convex part, and the 2nd surface of the above-mentioned crevice to the 1st surface And a recess region, and the recess region is thinner than the recess region because the content of cotton in the first fiber layer is smaller than that of the protrusion region, and the above-mentioned dropout of cotton and exudation of excrement fluid In the recessed area where the tendency is particularly likely to occur, the possibility of the cotton in the first fiber layer falling to the outside is reduced, and the amount itself of the excrement fluid retained in the cotton is also reduced. It becomes difficult to exude on the skin-facing surface of (i.e., on the second surface of the non-woven fabric).
From the above, the nonwoven fabric of the present embodiment provides a nonwoven fabric for a liquid-permeable sheet of an absorbent article, in which the internal cotton is difficult to come off while having a good touch, and it is difficult to give a wet feeling to the wearer's skin. be able to.

Further, in another aspect (embodiment 2) of the present invention, in the nonwoven fabric of the above aspect 1, the recess has a bottom and a side wall extending from the bottom toward the protrusion, and the recess area The fiber mass of the cotton is included in the side wall part area | region which extends in the said thickness direction from the said 2nd surface of the said side wall part to the said 1st surface.

The nonwoven fabric of this embodiment is the thinnest in the recess area, and the bottom area where the above-mentioned dropout of cotton and exudation of excrement fluid are most likely to occur (that is, from the second surface to the first surface in the bottom of the recess) In the above-mentioned sidewall region adjacent to the extending region), cotton is contained in the form of a fiber mass, and such a fiber mass is a form in which fibers (cotton) exist in a dispersed state (ie, individual fibers are independent) The non-woven fabric of the present embodiment, which contains such fiber mass of cotton, is more reliable in suppressing the coming off of the cotton in the recessed area, since it is easy to absorb and hold the excrement fluid in addition to being bulky. However, it is possible to further suppress exudation of the excretory fluid, particularly from the bottom region, by preferentially absorbing and retaining the excretory fluid in the cotton fiber mass in the side wall region.

In still another aspect (aspect 3) of the present invention, in the nonwoven fabric of the above aspect 2, the convex portion is a ridge portion extending in a first direction, and the concave portion is in a second direction orthogonal to the first direction. And a groove extending adjacent to the ridge and extending in the first direction, and the cotton fiber mass is present in the first fiber layer from the convex area to the concave area.

In the non-woven fabric of the present embodiment, since the above-described cotton fiber mass is present in the first fiber layer from the convex area to the concave area, in the concave area having a relatively high fiber density, the first fiber layer While the fiber mass of cotton can be supported steadily by the thermoplastic resin fiber etc. inside, in the convex region where the fiber density is relatively low, physical load such as vibration is applied to the non-woven fabric to move the fiber mass In such a case, it is possible to secure a minute space that can tolerate the movement of the fiber mass (in other words, it can support the cotton fiber mass while responding to physical loads such as vibration). The nonwoven fabric of the present embodiment can make it more difficult for the cotton to come off more reliably even in an environment where physical load such as vibration is likely to be applied.

In still another aspect (aspect 4) of the present invention, in the nonwoven fabric of the above-mentioned aspect 3, the cotton fiber mass existing across the convex region to the concave region is a portion of the portion existing in the convex region. The length in the direction of 2 is longer than the length in the second direction of the portion present in the recessed area.

In the nonwoven fabric of the present embodiment, in the fiber mass of cotton existing from the convex region to the concave region of the nonwoven fabric of the third embodiment, the length in the second direction of the portion present in the convex region is present in the concave region Since it is longer than the length in the second direction of the part, it is more difficult for the cotton to fall off as in the non-woven fabric of the third embodiment described above, while the excretory fluid is made of cotton fiber lumps (more specifically Can be preferentially absorbed and held in the convex region by the portions present in the convex region of the cotton fiber mass, and it is possible to make it more difficult to exude the excrement fluid from the above-mentioned concave region it can.

In still another aspect (aspect 5) of the present invention, in the nonwoven fabric according to any one of the aspects 2 to 4, the fiber mass of the cotton is closer to the first surface side in the thickness direction in the first fiber layer. It is ubiquitous.

In the non-woven fabric of the present embodiment, the non-woven fabric of the present embodiment is used as a liquid-permeable sheet of the absorbent article because the above-mentioned cotton fiber mass is unevenly distributed near the first surface in the thickness direction in the first fiber layer. When this happens, a cotton fiber mass will be present at a position further away from the skin-facing surface of the liquid-permeable sheet (that is, the second surface of the non-woven fabric), and the cotton fiber mass holds waste fluid. However, it is even more difficult to exude to the skin-facing surface of the liquid-permeable sheet.

In still another aspect (aspect 6) of the present invention, in the nonwoven fabric according to any one of the aspects 2 to 5, the cotton fiber mass is partially exposed from the first surface.

Since the nonwoven fabric of this embodiment has a portion of the cotton fiber mass exposed from the first surface, when the nonwoven fabric of this embodiment is used for the liquid permeable sheet of the absorbent article, the non-skin facing of the liquid permeable sheet A portion of the fiber mass exposed from the surface (that is, the first surface of the non-woven fabric) acts as a bridge to facilitate transfer of the excrement fluid to a member such as an absorber located on the non-skin facing surface side of the liquid permeable sheet. be able to.
Thereby, the nonwoven fabric of the present embodiment can improve the absorption performance of the absorbent article and can make rewet less likely to occur, so that it is more difficult to give a wet feeling to the wearer's skin Can.

In still another aspect (aspect 7) of the present invention, in the nonwoven fabric of the above-mentioned aspect 6, the cotton has a flat cross-sectional shape in a part of fibers.

The nonwoven fabric of the present embodiment is a nonwoven fabric of the above-mentioned embodiment 6, since the cross-sectional shape of a part of cotton fibers is flat, when the nonwoven fabric of this embodiment is used for a liquid permeable sheet of an absorbent article, a liquid permeable sheet The cotton fibers contained in a part of the fiber mass exposed from the non-skin facing surface of the fabric easily contact with a member such as an absorber located on the non-skin facing surface side of the liquid permeable sheet with a wider contact area, The liquid can be transferred to the member such as the absorber more efficiently.

In still another aspect (aspect 8) of the present invention, in the nonwoven fabric according to any one of the above aspects 2 to 7, the cotton fiber mass comprises a mass portion where cotton fibers are aggregated, and the first surface side from the mass portion And a diffusion fiber portion made of a plurality of cotton fibers extending in a plane direction toward the surface.

In the non-woven fabric of this aspect, since the above-mentioned cotton fiber mass has a specific structure having the above-mentioned mass portion and the diffusion fiber portion, the cotton fiber of the above-mentioned diffusion fiber portion is the thermoplastic resin in the first fiber layer. The fibers can be entangled with each other or enter between the fibers of the thermoplastic resin fibers to exert an anchoring effect, and the above-mentioned cotton fiber mass can be made more difficult to be reliably removed from the first surface side.
Furthermore, when the non-woven fabric of the present embodiment is used for a liquid-permeable sheet of an absorbent article, the above-mentioned cotton is made of the waste fluid supplied to the skin-facing surface of the liquid-permeable sheet and permeated in the thickness direction. In the diffusion fiber part, while absorbing and holding intensively (spotwisely) in the lump part of the fiber lump, in the diffusion fiber part, the waste fluid held in the above mass part is diffused in the surface direction of the liquid permeable sheet and thickness direction Since it can be made to transfer to the non-skin opposing surface side (ie, the 1st surface side of the nonwoven fabric), the excretory fluid can be transferred from a wider area to a member such as an absorber, and the liquid permeable sheet It is possible to make it even more difficult to cause liquid return of the excrement fluid from the non-skin facing surface side to the skin facing surface side and, further, exudation (rewet) of the excrement fluid onto the skin facing surface of the liquid permeable sheet.

In still another aspect (aspect 9) of the present invention, in the nonwoven fabric according to any one of the aspects 1 to 8, the thermoplastic resin fiber contained in the second fiber layer has a fineness contained in the first fiber layer It is larger than the fineness of each of the thermoplastic resin fiber and the cotton.

In the nonwoven fabric of the present embodiment, since the fineness of the thermoplastic resin fiber contained in the second fiber layer is larger than the fineness of each of the thermoplastic resin fiber and the cotton contained in the first fiber layer, the first fineness is relatively small. The thermoplastic resin fiber and cotton contained in the fiber layer tend to be entangled with the thermoplastic resin fiber contained in the first fiber layer or in the second fiber layer, and the cotton and the thermoplastic resin fiber disassociate in the first fiber layer Even when the non-woven fabric contains cotton as a constituent component, it is possible to exhibit excellent strength or shape-retaining property because it becomes difficult to cause division or delamination between the respective fiber layers. Furthermore, since the inter-fiber distance of the thermoplastic resin fiber contained in the second fiber layer tends to be relatively smaller than the inter-fiber distance of the thermoplastic resin fiber and cotton contained in the first fiber layer, the first fiber layer The fibers contained therein (in particular, cotton) are less likely to pass through the second fiber layer to the second surface side (i.e., the cotton is less likely to come off to the outside), and rewetting is further less likely to occur.

Yet another aspect (embodiment 10) of the present invention is a nonwoven fabric roll for a liquid-permeable sheet of an absorbent article, wherein the nonwoven fabric of any of the above-mentioned embodiments 1 to 9 is wound up in a roll.

The non-woven fabric roll of this embodiment uses non-woven fabric in which the cotton in the non-woven fabric is unlikely to come out to the outside even if physical load such as friction or vibration is applied (that is, the non-woven fabric of any of the above-mentioned embodiments 1 to 9). The non-woven fabric can be provided as a material adapted to high-speed production of an absorbent article (that is, production under conditions in which physical load such as friction or vibration is likely to be applied) while suppressing the falling off of cotton.

In still another aspect (embodiment 11) of the present invention, in the nonwoven fabric roll of the above-mentioned embodiment 10, the first surface of the nonwoven fabric is a net surface.

In the nonwoven fabric roll of this aspect, since the first surface of the nonwoven fabric is a net surface having a relatively high fiber density, when the nonwoven fabric is wound into a roll during the manufacturing process of the nonwoven fabric or from the nonwoven fabric roll during the manufacturing process of the absorbent article Even when non-woven fabrics overlapping in the thickness direction rub against each other when the non-woven fabric is unwound, the surface structure of the first surface (net surface) having a high fiber density hardly changes, and the cotton contained in the first fiber layer It can be made hard to come off from the 1 side.

According to the present invention, it is possible to provide a non-woven fabric for a liquid-permeable sheet of an absorbent article, which has a good touch, is resistant to internal cotton falling off, and hardly gives a moist feeling to the wearer's skin.

FIG. 1 is a plan view of a disposable diaper 1 using a nonwoven fabric 20 according to an embodiment of the present invention as a top sheet 2. FIG. 2 is a partial cross-sectional view of the disposable diaper 1 taken along the line II-II ′ in FIG. FIG. 3 is a partial perspective view of the nonwoven fabric 20 according to an embodiment of the present invention. FIG. 4 is a cross-sectional view of the nonwoven fabric 20 taken along the line IV-IV 'in FIG. FIG. 5: is a figure which shows typically the aspect of the constituent fiber of the nonwoven fabric 20 in sectional drawing of FIG. FIG. 6 is an enlarged view of a portion surrounded by the VI line in FIG. FIG. 7 is a view corresponding to FIG. 5 of a nonwoven fabric 20 'according to another embodiment of the present invention. FIG. 8 is a perspective view of the non-woven fabric roll 200 in which the non-woven fabric 20 is wound up in a roll shape.

Hereinafter, preferred embodiments of the nonwoven fabric of the present invention will be described in detail with reference to the drawings. In the present specification, “an object (for example, a non-woven fabric, an absorbent article, a surface sheet, etc.) placed on a horizontal surface in the unfolded state is In the case of an absorbent article, "looking in the thickness direction of the object from the top sheet side" is simply referred to as "planar view".

About various directions etc. which are used in this specification, unless there is particular notice, it is as follows.
In the present specification, "longitudinal direction" refers to "long direction of the length of a longitudinally long object (for example, absorbent article, non-woven fabric, etc.) in plan view", and "width direction" refers to "longitudinal in plan view""Lengthdirection" refers to the direction "perpendicular to the object placed on the horizontal plane in the unfolded state", and their longitudinal direction The width direction and the thickness direction are orthogonal to each other. Further, in the present specification, the “plane direction” refers to “a direction (that is, a horizontal direction) in which a flat surface of a substantially sheet-like object (for example, non-woven fabric, absorbent article, surface sheet, etc.) extends in plan view”. The surface direction and the thickness direction are orthogonal to each other.
Furthermore, in the present specification, unless otherwise specified, in the thickness direction of the absorbent article, "proximal to the wearer's skin surface when wearing the absorbent article" is "skin-facing surface It is called "side", and "the distal side relative to the skin surface of the wearer when wearing the absorbent article" is referred to as "non-skin facing surface side".
In addition, in this specification, the "skin facing surface side" and "non-skin facing surface side" of the absorbent article and various members (for example, top sheet, absorber, back sheet, etc.) constituting the absorbent article The “surface of” may be simply referred to as “skin facing surface” and “non-skin facing surface”, respectively.

FIG. 1 is a plan view of a disposable diaper 1 using a nonwoven fabric 20 according to an embodiment of the present invention as a surface sheet 2, and FIG. 2 is a cross-sectional view of the disposable diaper 1 along the line II-II ′ in FIG. FIG.
As shown in FIG. 1, the disposable diaper 1 (an example of the “absorbent article” in the present invention) has a longitudinal direction L and a width direction W in plan view, and further, substantially in the longitudinal direction L The central portion has a generally sandglass-like longitudinal outer shape narrowly narrowing inward in the width direction W. In addition, the external shape of the absorbent article to which the nonwoven fabric of the present invention is applied is not limited to such an aspect, and it may be an elongated shape in which the length in the longitudinal direction L is longer than the length in the width direction W For example, any vertically long shape (for example, a rectangle, an ellipse, a bowl shape, etc.) according to various applications etc. can be adopted.

Furthermore, as shown in FIG. 2, the disposable diaper 1 is a liquid-permeable top sheet 2 (non-woven fabric 20) according to the embodiment of the present invention, which is located on the skin facing surface side in the thickness direction T. And the liquid-impermeable back sheet 3 located on the non-skin facing surface side, and the liquid-absorbent absorbent body 4 located between the two sheets. , As a main component.
Moreover, in this disposable diaper 1, as shown to FIG. 1 and FIG. 2, a pair of liquid-

impermeable side sheets

5 and 5 which form a leak-proof wall part and the both ends in the width direction W of the disposable diaper 1 (I.e.,

elastic members

6, 6 made of thread rubber or the like for expanding and contracting in the longitudinal direction L respectively for the left and right leg circumference portions coming into contact with the wearer's thighs) And

connection sheets

7 and 7 for connecting the back facing area, and an exterior sheet (not shown) disposed on the non-skin facing surface side of the back sheet 3 as structural components. That is, the disposable diaper 1 is a so-called tape-type disposable diaper.
In addition, in the disposable diaper 1 shown in FIG. 1, the area at one end side of the longitudinal direction L located in the lower part of FIG. 1 is an abdominal facing area facing the abdomen of the wearer, and the longitudinal direction located in the upper part of FIG. The area on the other end side of L is a back facing area corresponding to the back (hip) of the wearer.

Moreover, in the above-mentioned disposable diaper 1, about constituent members other than surface sheet 2, especially if it can function as various constituent members of an absorptive article, it will not be restricted especially, but arbitrary constituent members known in the field may be used. It can be used.

For example, the back sheet 3 is disposed on the non-skin facing surface side (lower side of the absorber 4 in FIG. 2) in the disposable diaper 1 to prevent permeation of waste fluid such as urine discharged from the wearer, It is formed of a liquid impermeable sheet that functions to prevent the excrement fluid from leaking out to the wearer's underwear and clothes. In addition, although the liquid impermeable sheet which forms a back surface sheet does not permeate | transmit liquids, such as a waste liquid, it is preferable to be equipped with predetermined | prescribed air permeability. When the back sheet has such air permeability, the moisture released from the absorber (specifically, the moisture derived from the excretory fluid absorbed and held by the absorber) is absorbed through the back sheet. Since it is easy to discharge | release to the exterior of a sex article, it can make it hard to collect moisture between the inside of an absorbent article, or an absorbent article, and a wearer's skin surface.

The liquid impermeable sheet which can be used as the back sheet is not particularly limited, and, for example, any hydrophobic thermoplastic resin fiber (for example, polyolefin fiber such as polyethylene (PE), polypropylene (PP), etc., polyethylene terephthalate (PET) And the like), various composite fibers such as core-sheath type, etc.); a breathable resin film formed of hydrophobic thermoplastic resin such as PE and PP; It is possible to use any liquid-impermeable sheet such as a laminate obtained by laminating non-woven fabrics on one another; and laminated non-woven fabrics such as SMS non-woven fabrics.

The thickness, basis weight, outer shape and the like of the back sheet are not particularly limited as long as the effects of the present invention are not impaired, and any thickness, basis weight, outer shape and the like according to desired leakproof performance, air permeability, strength, etc. Can be adopted. In addition, in the above-mentioned disposable diaper 1, the peripheral part is joined with the surface sheet 2 in the state which pinched | interposed the absorber 4 between the surface sheets 2 and the back surface sheet 3. FIG.

In the above-described disposable diaper 1, the absorbent body 4 is disposed between the top sheet 2 and the back sheet 3, and can absorb and retain waste fluid such as urine that has passed through the top sheet 2. It is formed of an absorbent member having a liquid absorbing property. The absorber 4 extends over a wide range in the longitudinal direction L of the disposable diaper 1 in plan view, as shown in FIG. 1, and a substantially central portion in the longitudinal direction L extends inward in the width direction W. It has a generally hourglass-shaped vertically long outer shape that narrows toward the side. In addition, the absorber of the absorbent article to which the nonwoven fabric of this invention is applied is not limited to the thing of such a mode, Arbitrary longitudinal shape (for example, a rectangle, an ellipse, wedge shape according to various uses etc.) Etc.) can be adopted.

The absorbent member that can be used as the absorbent is not particularly limited as long as it can absorb and retain excrement fluid such as urine, and for example, from an absorbent material containing at least one of a water absorbent fiber and a superabsorbent polymer Using an absorbent core and at least one liquid-permeable core wrap sheet (for example, a tissue made of hydrophilic cellulose-based fibers) covering the outer peripheral surface of the absorbent core, etc. it can. Here, as the water-absorbent fibers, for example, cellulose fibers and the like can be used, and more specifically, wood pulp obtained using softwood or hardwood as a raw material; non-wood pulp such as kenaf, hemp, cotton, etc .; rayon And regenerated cellulose such as fibril rayon; semi-synthetic cellulose such as acetate and triacetate. Further, as the superabsorbent polymer, for example, granules such as starch-based superabsorbent polymer; synthetic polymer-based superabsorbent polymer such as sodium acrylate copolymer (so-called "SAP") can be used.

The thickness, basis weight and the like of the absorber are not particularly limited as long as the effects of the present invention are not impaired, and any thickness, basis weight and the like according to desired absorption performance, flexibility and the like can be adopted. In addition, the thickness, basis weight, and the like of the absorber may be constant or may be partially different over the entire surface direction of the absorber. In addition, the absorbent article to which the nonwoven fabric of the present invention is applied is not provided with such an absorbent if components (for example, a surface sheet etc.) other than the absorbent have predetermined liquid absorption properties. May be

In the disposable diaper 1 described above, the absorbent body 4 is joined to the top sheet 2 on the skin facing surface and to the back sheet 3 on the non-skin facing surface by any bonding means such as a hot melt adhesive. There is.

And in the above-mentioned disposable diaper 1, as shown in FIG. 2, the liquid-permeable top sheet 2 is arrange | positioned at the skin opposing surface side (upper side of the absorber 4 in FIG. 2), and is discharged | emitted from a wearer. Formed by a liquid-permeable sheet that functions to rapidly transfer waste fluid such as urine toward the absorber 4 and, further, in the above-mentioned disposable diaper 1, the liquid-permeable sheet of the present invention is used as the liquid-permeable sheet. The nonwoven fabric 20 which concerns on one Embodiment is used.
In addition, in the above-mentioned disposable diaper 1, although the surface sheet 2 has a rectangular-shaped external shape long in the longitudinal direction L in planar view, as shown in FIG. 1, the nonwoven fabric of this invention is applied The absorbent article to be used is not limited to such an embodiment, and the top sheet may have an arbitrary outer shape according to various applications and the like.

Hereinafter, the nonwoven fabric 20 which concerns on one Embodiment of this invention is demonstrated still in detail, referring drawings.
Here, FIG. 3 is a partial perspective view of the nonwoven fabric 20 according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view of the nonwoven fabric 20 taken along the line IV-IV ′ in FIG.

As shown in FIGS. 3 and 4, the non-woven fabric 20 according to the present embodiment has a first direction D ₁ corresponding to the longitudinal direction L of the disposable diaper 1 and a second direction D corresponding to the width direction W of the disposable diaper 1. the direction D _2, which has a thickness direction T perpendicular to these directions, and a first surface 2a and second surface 2b opposed to each other in the thickness direction T.
And the nonwoven fabric 20 which concerns on this embodiment forms the 1st surface 2a used as the non-skin opposing surface of the surface sheet 2 (liquid-permeable sheet) in the disposable diaper 1, as shown in FIG.3 and FIG.4 a first fiber layer 21 containing C and the thermoplastic resin fibers F _1, to form a second surface 2b which is a skin-facing surface of the topsheet 2, the second fiber not containing and cotton include thermoplastic resin fibers F ₂ The plurality of convex portions 23 configured by the layer 22 and further projecting in the direction from the first surface 2a toward the second surface 2b, and the plurality of concave portions 24 indented in the direction from the second surface 2b toward the first surface 2a And have. Furthermore, as shown in FIG. 4, the nonwoven fabric 20 has a plurality of convex region 23 A extending in the thickness direction T from the second surface 2 b of the convex 23 to the first surface 2 a in each of the plurality of convex portions 23 Each recess 24 has a recess area 24A extending in the thickness direction T from the second surface 2b to the first surface 2a of the recess 24, and the recess area 24A is formed of cotton in the first fiber layer 21. The content of C is smaller than that of the convex region 23A.

Thus, the nonwoven fabric 20 has a first fibrous layer 21 including the Cotton C and the thermoplastic resin fibers F _1, is constituted by a second fibrous layer 22 not containing and cotton include thermoplastic resin fibers F _2, and Since the plurality of convex portions 23 and the plurality of concave portions 24 described above are provided, the skin facing surface of the surface sheet 2 in the disposable diaper 1 is exhibited while exhibiting a good touch by the plurality of convex portions 23 and the concave portions 24 That is, cotton C is contained in the first fiber layer 21 at a position distant from the second surface 2b) of the non-woven fabric 20 (in other words, the skin facing surface side of the first fiber layer 21 containing cotton C) The second fiber layer 22 intervenes in the following), and it is difficult for the cotton C to fall out from the skin-facing surface side of the surface sheet 2 (that is, the second surface 2b side of the nonwoven fabric 20) to the outside as a whole. parent Even if the sexual cotton C is absorbing and retaining bodily fluid such as urine discharged from the wearer, the liquid waste is not easily exudation onto the skin-facing surface of the topsheet 2.
Furthermore, the non-woven fabric 20 has a thickness from the second surface 2b to the first surface 2a of the convex portion 23A extending in the thickness direction T from the second surface 2b to the first surface 2a of the convex portion 23 The recess area 24A extends in the longitudinal direction T, and the recess area 24A has a smaller thickness because the content of cotton C in the first fiber layer 21 is smaller than that of the projection area 23A. In the recessed area 24A where the above-mentioned drop of the cotton C and exudation of the excrement fluid are particularly likely to occur, the possibility of the cotton C in the first fiber layer 21 falling to the outside is reduced and the amount of excrement fluid retained in the cotton C As the amount itself decreases, the excretory fluid is less likely to exude on the skin-facing surface of the topsheet 2 (that is, on the second surface 2b of the nonwoven fabric 20).
Therefore, the nonwoven fabric 20 according to the present embodiment forms the surface sheet 2 (liquid-permeable sheet) in which the internal cotton C is hard to come off while providing a good touch, and hardly gives the wearer's skin a moist feeling. be able to.

Here, in the present specification, the content of cotton in each of the convex region and the concave region can be obtained, for example, as follows. That is, (1) After cutting out the sample of the area | region which becomes object from the nonwoven fabric dried beforehand at 105 degreeC for 1 hour, the initial mass (g) of this sample is measured. (2) Immerse the sample in 70% sulfuric acid for 1 hour to dissolve the cotton. (3) The sample after the sulfuric acid immersion is washed with about 6 liters of water with suction on a Buchner funnel, and further washed with about 1 liter of pure water. (4) After drying the washed sample at 105 ° C. for 2 hours, measure the post-treatment mass (g) of the sample. (5) The cotton-containing mass (g) in the sample is calculated by subtracting the post-treatment mass of the sample from the initial mass of the sample, and further, the obtained cotton-containing mass is converted to the mass per unit plan view area By doing this, the above-mentioned cotton content can be obtained.
Therefore, the magnitude relation of the content of cotton in each of the above-mentioned convex part area and the concave part area can be obtained by determining the content of cotton in each area and then comparing them. In addition, if it was in the measurement of content of the above-mentioned cotton, it measures in five different places arbitrary, and adopts the average value.

Further, in the present specification, the convex portion and the concave portion are partitioned as follows. That is, as shown in FIG. 4, when the non-woven fabric is placed on a horizontal surface with the first surface of the non-woven fabric facing downward, the portion with the highest height of the second surface is taken as the "highest portion" The position where the height difference between the highest and deepest parts is divided equally into two parts where the lowest part of the two faces is the “deepest part” of the concave (that is, the thickness direction from the highest and deepest parts) distance is a virtual reference horizontal plane P portion projecting upward than _B spread d / 2 and a position), respectively "convex portion", the portion recessed downward is "concave".
In addition, the “top” (see “top 231” in FIG. 4) of the convex portion described later includes the above-mentioned highest portion and the distance in the thickness direction from the highest portion is the height of the entire convex portion (ie, , D / 2), and the “bottom” of the recess (see “bottom 241” in FIG. 4) includes the deepest portion described above and in the thickness direction from the deepest portion It refers to a portion where the distance is within 3% of the depth (i.e., d / 2) of the entire recess.
Furthermore, in the present specification, as shown in FIG. 4, a region extending along the thickness direction from the second surface to the first surface of the convex portion is referred to as “convex portion region”, and the second surface of the concave portion A region extending along the thickness direction from the first surface to the first surface is referred to as a “recess region”.

Then, the nonwoven fabric 20 described above, as shown in FIG. 3, a plurality of protrusions 23 is formed as a ridge of the plurality of continuously extending in a first direction D _1, a plurality of recesses 24 , in a second direction D ₂ perpendicular to the first direction D ₁ and adjacent to the ridge portion (i.e., located between the ridge portion adjacent to the second direction D ₂₎ and the first direction D ₁ It is formed as a plurality of grooves extending continuously. Since the non-woven fabric 20 is provided with such a specific ridge-groove structure, it has excellent cushioning properties in the thickness direction T and can exert a good touch, and the drainage liquid can be expanded It can be diffused along the direction D _{1 of 1} (that is, the longitudinal direction L of the top sheet 2), and the disposable diaper 1 can be provided with excellent absorption performance.

In the present invention, the concavo-convex structure of the non-woven fabric (that is, the structure having a plurality of convex portions and concave portions) is not limited to the ridge and groove structure as in the above embodiment, and can express good touch. If it is, arbitrary concavo-convex structure is employable. As such a concavo-convex structure, for example, in the first direction between a plurality of rows of convex portions extending intermittently in the first direction and aligned in the second direction, and the convex portions adjacent in the second direction There may be mentioned a concavo-convex structure consisting of a plurality of rows of concave parts extending intermittently, a concavo-convex structure consisting of a plurality of hemispherical or cylindrical convex parts, and a plurality of concave parts located between adjacent convex parts.

In the present invention, the specific structure of peaks and valleys of the nonwoven fabric is not particularly limited as long as it can express a good feel, for example, the height of the protrusions (i.e., from the virtual reference horizontal plane P _B distance in the thickness direction of the up portion) is in the range of 0.1 mm ~ 3.0 mm, the depth of the recess (i.e., the distance in the thickness direction of the deepest part of the virtual reference horizontal plane P _B) is 0 The pitch of the plurality of projections (that is, the distance between the highest portions of two adjacent projections) is in the range of 0.5 mm to 5.0 mm.
Further, when the uneven structure of the non-woven fabric is a furrow structure, the width of the convex portion (that is, the length in the second direction of the portion where the length in the second direction in the convex portion is longest) is, for example, 0.1 mm The width of the recess (that is, the length in the second direction of the portion where the length in the second direction of the recess is the longest) is, for example, in the range of 0.1 mm to 5.0 mm. It is inside. The pitch and width of the convex portions and the concave portions can be measured from a planar photograph or a planar image by observing the nonwoven fabric in a non-pressured state by magnifying observation means such as a scanning electron microscope.

Moreover, in the above-mentioned embodiment, the 1st surface 2a used as the non-skin opposing surface of the surface sheet 2 has the substantially flat surface structure of the nonwoven fabric 20. As shown in FIG. Therefore, the non-woven fabric 20 can ensure a wider contact area with the absorber 4 disposed on the non-skin facing surface side of the surface sheet 2, and the waste fluid permeating the surface sheet 2 to the absorber 4 The migration can be made more efficiently and more reliably. In addition, when the first surface 2a of the non-woven fabric 20 has such a substantially flat surface structure, a sufficient thickness can be secured in the convex region 23A, so that it is included in the above-mentioned first fiber layer 21. Another advantage is that cotton C is less likely to come off.

In the present invention, the surface structure of the first surface of the non-woven fabric is not limited to such an aspect, for example, the first surface of the non-woven fabric has a portion corresponding to the convex portion on the second surface side and the thickness direction It may have a surface structure recessed toward the second surface side. When the first surface of the non-woven fabric has such a surface structure, the portion recessed toward the above-mentioned second surface side becomes a void portion, which can exhibit better cushioning properties. The void functions as a spacer between the surface sheet and the absorber, and the contact area with the absorber is also reduced, so that the waste fluid absorbed and held by the absorber is further transferred to the skin-facing surface of the surface sheet. There is an advantage that it is difficult to exude (that is, rewet does not easily occur).

The method of forming the uneven structure as described above on the non-woven fabric is not particularly limited. For example, a method of continuously blowing a gas (for example, air or the like) on the fiber web before forming the non-woven fabric Method, or a method using gear processing (hereinafter sometimes referred to as “gear processing method”), a method using vacuum forming or compression molding, or any other forming method can do. Above all, it is easy to unevenly distribute the cotton contained in the first fiber layer while shaping the concavo-convex structure (that is, the content of the cotton contained in the first fiber layer, the content in the recess region is the content of the protrusion region The gas spraying method is preferable in that it is easy to control to be smaller than the above.

Hereafter, each fiber layer which comprises the nonwoven fabric of this invention is demonstrated still in detail using the nonwoven fabric 20 which concerns on the above-mentioned embodiment.

[First fiber layer]
In the nonwoven fabric of the present invention, the first fiber layer forms a first surface which is the non-skin facing surface of the liquid-permeable sheet of the absorbent article to which the nonwoven fabric is applied, and comprises a cotton and thermoplastic resin fibers. It is composed of The cotton contained in the first fiber layer is not particularly limited, and, for example, cotton having a fineness of 1.0 dtex to 15 dtex and a fiber length of 5 mm to 40 mm can be used. Among them, in the case of cotton having a fiber length of 20 mm or more, when laminating the first fiber layer and the second fiber layer, part of the cotton fiber easily enters the inside of the second fiber layer, and Since the cotton fiber which entered inside can be bridged between the 1st fiber layer and the 2nd fiber layer and the liquid permeability of the whole nonwoven fabric can be improved, it can be used conveniently. Also, cotton with a fiber length of 20 mm or more (hereinafter sometimes referred to as "long-fiber cotton") and cotton with a fiber length of 10 mm or less (hereinafter sometimes referred to as "short-fiber cotton") are mixed. The mixed cotton can be used particularly preferably because the long fiber cotton can improve the liquid permeability of the non-woven fabric and the short fiber cotton can increase the bulk of the non-woven fabric.

The content of cotton in the first fiber layer is not particularly limited, but is, for example, in the range of 1% by mass to 70% by mass, preferably 2% by mass to 30%, from the viewpoint of water absorbency, water retention, flexibility and the like. It is in the range of mass%.
And in this invention, the cotton contained in the 1st fiber layer of a nonwoven fabric is unevenly distributed in the 1st fiber layer so that content in a crevice field may become smaller than content in a crevice field. is necessary. When the cotton is thus unevenly distributed in the first fiber layer, the possibility of the cotton falling off from the first surface side and the second surface side of the thin concave region is reduced, and the waste fluid retained in the cotton As the amount of the fluid itself is also reduced, the excretory fluid is less likely to exude on the surface of the non-woven fabric.

The means for uneven distribution of cotton in the first fiber layer as described above is not particularly limited, and for example, the above-mentioned gas spraying method can be used. Specifically, the second fiber layer is formed of thermoplastic resin fibers for the second fiber layer on a first fiber web formed by dispersing and mixing cotton substantially uniformly with the thermoplastic resin fibers for the first fiber layer. The fiber webs are stacked to form a laminated fiber web, and while conveying the laminated fiber web, a predetermined temperature and a predetermined pressure are applied to the surface (that is, the second surface) of the laminated fiber web on the second fiber web side. Forming a plurality of recesses in the laminated fiber web while interlacing the fibers in each fiber web and between the fiber webs by blowing a gas (e.g., air, etc.) After the cotton contained in the first fiber web is blown or moved to the lower region (ie, the convex region) side of the convex portion adjacent to the concave portion in the concave region) (ie, the first fiber web). After the laminated fiber web is distributed to the air-through heating device, the fibers in the respective fiber webs and between the respective fiber webs are fused together by the thermoplastic resin fibers in the heating device. By doing this, it is possible to obtain a non-woven fabric composed of the first fiber layer in which cotton is unevenly distributed as described above and the second fiber layer not containing cotton. According to the means using the gas spraying method, the uneven distribution of cotton contained in the first fiber layer can be easily achieved only by adjusting the pressure (jet pressure) of the gas sprayed onto the laminated fiber web and the jet conditions such as the jet diameter. In particular, it can be used because it can be realized.

In addition, the above-mentioned gear processing method can also be utilized as another means to make the above-mentioned cotton unevenly distributed in a 1st fiber layer, for example. Specifically, a first fiber web in which cotton is distributed unevenly in advance and a second fiber web made of thermoplastic resin fibers are laminated to produce a laminated fiber web, and then both sides of the laminated fiber web are paired. A first fiber layer and cotton in which cotton is unevenly distributed as described above are formed by sandwiching with a geared roll and locally pressing a portion with a low blending amount of cotton, thereby forming a plurality of recesses in the laminated fiber web. The nonwoven fabric which consists of the 2nd textiles layer which does not contain can be obtained.

Further, in the present invention, the cotton contained in the first fiber layer is dispersed in the form of a fiber aggregate which is an aggregate formed by gathering individual cotton fibers, and is dispersed in a matrix made of an aggregate of thermoplastic resin fibers. Is preferred.
Here, FIG. 5 is a figure which shows typically the aspect of the constituent fiber of the nonwoven fabric 20 in sectional drawing of FIG. 4, and FIG. 6 is an enlarged view of the part enclosed by VI line of FIG.

As shown in FIG. 5, in the non-woven fabric 20, in the first fiber layer 21, a cotton fiber mass CB is dispersed in a matrix made of an aggregate of thermoplastic resin fibers F ₁ . Thus, when the fiber mass of cotton is dispersed in the first fiber layer of the non-woven fabric, from the absorber located on the non-skin opposing surface side of the surface sheet (liquid permeable sheet) formed of the non-woven fabric, Even if the excrement fluid held in the absorbent body is released as moisture, intensively (spotly) absorb and retain the released moisture in the fiber mass of cotton in the above-mentioned first fiber layer. As a result, it is more difficult for the moisture (drainage fluid) released from the absorber to exude onto the skin-facing surface of the top sheet.

Furthermore, in the non-woven fabric 20 described above, the recess 24 has a bottom portion 241 and a side wall portion 242 extending from the bottom portion 241 toward the protrusion 23 as shown in FIGS. 24A includes the above-described cotton fiber mass CB in the side wall region 242A extending in the thickness direction T from the second surface 2b to the first surface 2a of the side wall portion 242. Thus, the non-woven fabric 20 described above is the thinnest in the recess area 24A, and the bottom area 241A in which the detachment of the cotton C and the exudation of the excrement fluid are most likely to occur (that is, the second surface of the bottom 241 of the recess 24). Cotton C is included in the form of a fiber mass CB in the above-mentioned side wall region 242A adjacent to the region extending in the thickness direction T from 2b to the first surface 2a, and further, the fiber mass CB is Such cotton fibers are more bulky than the form in which the fibers (cotton C) are present in a dispersed state (ie, the form in which the individual fibers are present alone), and because they are easy to absorb and retain waste fluid. The non-woven fabric 20 including the lump CB suppresses the dropout of the cotton C in the recessed area 24A to the outside more reliably, and removes the waste liquid from the cotton fiber lump C in the side wall area 242A. Priority is absorbed and be held, can be particularly difficult further cause exudation of liquid waste from the bottom region 241A to.

In this specification, the side wall portion of the recess, as shown in FIG. 4, from the bottom of the recess to the imaginary horizontal reference plane P _B described above (i.e., to the boundary of the convex portion and the concave portion) refers to the portion extending.

Further, in the non-woven fabric 20 described above, the cotton fiber mass CB is present, as shown in FIG. 5, in the first fiber layer 21 from the above-described convex area 23A to the recessed area 24A. As described above, when the fiber mass CB of cotton is present in the first fiber layer 21 from the projecting area 23A to the recessed area 24A, in the recessed area 24A having a relatively high fiber density, the first fiber while it is possible to steadily support the fibrous mass CB cotton by thermoplastic resin fibers F ₁ and the like in the layer 21, the lower convex regions 23A relatively fiber density, the physical load such as vibration nonwoven 20 In the case where the fiber mass CB is moved by the addition of the fiber mass, it is possible to secure a minute space that can accept the movement of the fiber mass CB (in other words, the fiber mass of cotton while responding to physical load such as vibration). Since CB can be supported, the above-mentioned non-woven fabric 20 can more reliably prevent the detachment of the cotton C even under an environment where physical load such as vibration is likely to be applied. In addition, about the fiber density of the above-mentioned convex part area and a crevice area, generally, when a concavo-convex structure is formed to a fiber web having a uniform fiber density in the surface direction, the fiber becomes relatively relatively in a concave area where the thickness becomes thin. The fiber density is relatively low in the convex area where the density is high and the thickness is maintained (in other words, the thickness is relatively high).

Furthermore, in the non-woven fabric 20 described above, the cotton fiber mass CB present across the convex region 23A to the concave region 24A is the second direction D of the portion existing in the convex region 23A as shown in FIG. the length of ₂ is longer than the second length in the direction D ₂ of the portion present in the recessed region 24A. Thus, in fiber mass CB from convex region 23A of the cotton that is present across the recessed region 24A of the nonwoven fabric 20, in the second direction D ₂ of the length recessed region 24A of the moieties present convex regions 23A When it is longer than the second length in the direction D ₂ of the portion present, while also more difficult to further rise to falling off of cotton C as described above, the excreted liquid by fibrous mass CB cotton (more specifically In the convex portion area 23A of the cotton fiber mass CB) can be absorbed and held preferentially in the convex portion area 23A, thereby further exuding the excrement fluid from the above-mentioned concave area 24A. It can be made hard to occur.

In addition, the length in the second direction of the portion present in each region of the fiber mass is, for example, a cross-sectional view of the target region enlarged by a scanning electron microscope, and the second direction of the portion present in the region It can be obtained by measuring the length of

Further, in the present invention, it is preferable that the fiber mass of cotton is unevenly distributed near the first surface side in the thickness direction in the first fiber layer. Thus, when the fiber mass of cotton is localized near the first surface side in the thickness direction in the first fiber layer, when the non-woven fabric is used for the liquid-permeable sheet of the absorbent article, Even if the fiber mass of cotton exists at a position further away from the surface facing the skin (that is, the second surface of the non-woven fabric) and the fiber mass of cotton holds the excretory fluid, the liquid permeable sheet Exudation to the skin facing surface becomes even more difficult.

Furthermore, in the non-woven fabric 20 described above, as shown in FIGS. 5 and 6, a part of the cotton fiber mass CB is exposed from the first surface 2 a of the non-woven fabric 20 (“fiber mass CB in FIG. Exposed part CB _d "). As described above, when a part of the cotton fiber mass CB is exposed from the first surface 2a, it is exposed from the non-skin opposing surface of the surface sheet 2 formed by the non-woven fabric 20 (that is, the first surface 2a of the non-woven fabric 20). A portion of the fiber mass CB (more specifically, as shown in FIG. 6, the cotton fibers C _d contained in the exposed portion CB _d of the fiber mass CB) becomes a bridge, and the non-skin facing of the surface sheet 2 The waste fluid can be easily transferred to the absorber 4 located on the surface side. Thereby, the above-mentioned non-woven fabric 20 can further improve the absorption performance of the disposable diaper 1 and can make rewet less likely to occur, thereby making it even more difficult to give a wet feeling to the wearer's skin be able to.

Furthermore, when a portion of the cotton fiber mass is thus exposed from the first surface, it is preferable that the cotton has a flat cross-sectional shape in a portion of the fiber. When the non-woven fabric is used for the liquid-permeable sheet of the absorbent article that the cross-sectional shape of a part of the cotton fiber is flat, from the non-skin facing surface of the liquid-permeable sheet (that is, the first surface of the non-woven fabric) An absorbent body or the like in which a cotton fiber (see “cotton fiber C _d ” contained in exposed part CB _d in FIG. 6) contained in a part of the exposed fiber mass is located on the non-skin opposing surface side of the liquid permeable sheet It is easy to contact with a member with a wider contact area, and waste fluid can be more efficiently transferred to a member such as an absorber.

Further, in the non-woven fabric of the present invention, the fiber mass of cotton is a diffusion made up of a mass part where the cotton fibers are aggregated and a plurality of cotton fibers extending in the surface direction from the mass part toward the first surface side. It is particularly preferred to have a particular structure having a fiber part. Here, FIG. 7 is a figure corresponding to FIG. 5 of nonwoven fabric 20 'which concerns on another embodiment of this invention. In addition, since the structure except the structure different from the nonwoven fabric 20 which concerns on the above-mentioned embodiment is fundamentally the same as that of the above-mentioned embodiment, description is abbreviate | omitted.

As shown in FIG. 7, in the non-woven fabric 20 ′ according to another embodiment of the present invention, the fiber mass CB of cotton contained in the first fiber layer 21 is a mass portion BP in which fibers of cotton C are aggregated, It has a specific structure having a diffusion fiber portion DP made of a plurality of fibers of cotton C which extends in a surface direction from the mass portion BP toward the first surface 2a side. In the non-woven fabric 20 ′, the cotton fiber mass CB has a specific structure having the above-mentioned mass portion BP and the diffusion fiber portion DP, so the cotton fiber of the above-mentioned diffusion fiber portion DP is the first fiber layer or intertwined with the thermoplastic resin fibers F ₁ in 21, it exhibits an anchoring effect to intrude between the fibers of the thermoplastic resin fibers F _1, further reliably fibrous mass CB of the aforementioned cotton from the first surface 2a side It can be made hard to come off. Furthermore, the non-woven fabric 20 'is supplied to the skin-facing surface of the surface sheet 2 formed by the non-woven fabric 20', and the excretory fluid permeated in the thickness direction T is the lump BP of the above-mentioned cotton fiber lump CB. In the diffusion fiber portion DP, non-skin in the thickness direction T while diffusing and retaining the excrement fluid held in the mass portion BP in the surface direction of the surface sheet 2 while absorbing and holding intensively (spotwisely) in the Since the liquid can be transferred to the opposite surface side (that is, the first surface 2a side of the non-woven fabric 20 ′), the excretory fluid can be transferred from a wider area to the absorber 4 and the non-skin of the surface sheet 2 is It is possible to make it even more difficult for the drainage liquid to return from the opposing surface side to the skin-facing surface side, and thus to make the excretion liquid (rewet) on the skin-facing surface of the top sheet 2 more difficult.

Next, the thermoplastic resin fiber contained in the first fiber layer will be described.
In the present invention, the thermoplastic resin fiber contained in the first fiber layer is not particularly limited as long as it is a fiber made of a thermoplastic resin, and examples of the thermoplastic resin include polyethylene (PE), polypropylene (PP), Olefin resins such as ethylene-vinyl acetate copolymer (EVA); polyester resins such as polyethylene terephthalate (PET) and polylactic acid (PLA); and known resins such as polyamide resins such as 6-nylon, These resins may be used alone or in combination of two or more.
In addition, the structure of fibers made of such a thermoplastic resin is not particularly limited, and, for example, composite fibers such as core-sheath fibers such as PET / PE, side-by-side fibers, and islands / sea fibers; Hollow type fibers; flat-shaped, Y-shaped, C-shaped modified cross-section type fibers, etc. may be mentioned, and fibers having these structures may be used alone or in combination of two or more types of fibers.

The fineness of the thermoplastic resin fiber contained in the first fiber layer is not particularly limited, but is usually in the range of 0.6 dtex to 8.8 dtex in terms of strength, flexibility, touch, liquid permeability, etc. of the non-woven fabric. , Preferably in the range of 1.1 dtex to 4.6 dtex. Moreover, it is preferable that the fineness of the thermoplastic resin fiber contained in this 1st fiber layer is smaller than the fineness (fiber diameter) of the thermoplastic resin fiber contained in the 2nd fiber layer mentioned later. Thus, when the fineness of the thermoplastic resin fiber contained in the first fiber layer is smaller than the thermoplastic resin fiber contained in the second fiber layer, the thermoplastic resin fiber with a small fineness contained in the first fiber layer is Since it becomes easy to become entangled with the thermoplastic resin fiber contained in the cotton contained in the same 1st fiber layer and the 2nd fiber layer, the division of the 1st fiber layer accompanying dissociation of cotton and a thermoplastic resin fiber and the interlayer between each fiber layer Peeling hardly occurs, and even if the non-woven fabric contains cotton as a component, it can exhibit excellent strength or shape retention.

The fiber length of the thermoplastic resin fiber contained in the first fiber layer is not particularly limited as long as the effects of the present invention are not impaired, but from the viewpoint of strength, flexibility, liquid permeability and the like of the non-woven fabric, usually 20 mm to 100 mm. And preferably in the range of 30 mm to 65 mm. The thermoplastic resin fiber may be subjected to a hydrophilization treatment, and as such a hydrophilization treatment, for example, a treatment using a surfactant, a hydrophilic agent or the like (for example, kneading of the surfactant into the inside of the fiber) And coating the surface of the fiber with a surfactant.

In the present invention, the content of the thermoplastic resin fiber contained in the first fiber layer is not particularly limited as long as the effects of the present invention are not impaired, but from the viewpoint of strength and flexibility of the non-woven fabric, for example, 30% by mass to 99%. It is in the range of mass%, preferably in the range of 70 mass% to 98 mass%. The first fiber layer may contain fibers other than cotton and thermoplastic resin fibers, optional additives, and the like, as long as the effects of the present invention are not impaired.

[Second fiber layer]
Next, the second fiber layer constituting the nonwoven fabric of the present invention will be described.
In the non-woven fabric of the present invention, the second fiber layer forms a second surface which is the skin-facing surface of the liquid-permeable sheet of the absorbent article to which the non-woven fabric is applied, and contains thermoplastic resin fibers and does not contain cotton. It is comprised by the fiber layer. The thermoplastic resin fiber contained in the second fiber layer is not particularly limited as long as it is a fiber made of a thermoplastic resin, but is a fiber made of a thermoplastic resin having hydrophobicity, that is, a hydrophobic thermoplastic resin fiber Is preferred. When the second fiber layer forming the second surface of the non-woven fabric (that is, the surface facing the skin of the liquid-permeable sheet of the absorbent article to which the non-woven fabric is applied) is composed of such hydrophobic thermoplastic resin fibers, The second fiber layer, which may come into direct contact with the wearer's skin, makes it difficult to absorb and hold excretory fluid and moisture, so that it is possible to make it even more difficult for the wearer's skin to feel moist.

Here, "hydrophobic" in the present specification means a property which is difficult to be compatible with water or difficult to retain water, and refers to, for example, one having a contact angle with ion exchange water of about 80 ° to 100 °. . The contact angle with ion exchange water can be measured, for example, by the method described in “Measurement of initial contact angle” in JP-A-2005-324010.

The thermoplastic resin fibers contained in the second fiber layer may be the same as the fibers exemplified as the thermoplastic resin fibers contained in the above-mentioned first fiber layer, but it is easy to entangle the fibers between the respective fiber layers In terms of length and the like, the same fibers as the thermoplastic resin fibers contained in the above-mentioned first fiber layer (that is, the same material (resin) as the thermoplastic resin fibers contained in the first fiber layer, the same fiber length and the same It is preferable to use a fiber having a structure).

Further, the fineness of the thermoplastic resin fiber contained in the second fiber layer is not particularly limited, but is usually in the range of 0.6 dtex to 8.8 dtex in terms of strength, flexibility, touch, liquid permeability, etc. of the non-woven fabric. And preferably in the range of 1.1 dtex to 4.6 dtex. Furthermore, it is preferable that the fineness of the thermoplastic resin fiber contained in this 2nd fiber layer is larger than the fineness of each of the thermoplastic resin fiber and the cotton which are contained in the above-mentioned 1st fiber layer. Thus, when the fineness of the thermoplastic resin fiber contained in the second fiber layer is larger than the fineness of each of the thermoplastic resin fiber and the cotton contained in the first fiber layer, the first fiber layer having a relatively small fineness is used. Since the thermoplastic resin fiber and cotton contained are easily entangled with the thermoplastic resin fiber contained in the first fiber layer or in the second fiber layer, the split of the first fiber layer caused by the dissociation of the cotton and the thermoplastic resin fiber Also, delamination between the fiber layers is less likely to occur, and even if the non-woven fabric contains cotton as a component, it can exhibit excellent strength or shape retention. Furthermore, since the inter-fiber distance of the thermoplastic resin fiber contained in the second fiber layer tends to be relatively smaller than the inter-fiber distance of the thermoplastic resin fiber and cotton contained in the first fiber layer, the first fiber layer The fibers contained therein (in particular, cotton) are less likely to pass through the second fiber layer to the second surface side (i.e., the cotton is less likely to come off to the outside), and rewetting is further less likely to occur.

In addition, the fineness of a fiber measures the cross-sectional area of the fiber by observing the cross-sectional shape of the fiber to be enlarged by using a scanning electron microscope and measures the cross-sectional area of the fiber and the specific gravity of the fiber (Specific gravity) can be calculated.

In the present invention, the second fiber layer may contain fibers other than the above-mentioned thermoplastic resin fibers, optional additives, and the like, as long as the effects of the present invention are not impaired.

Furthermore, in the present invention, the basis weight of each fiber layer constituting the non-woven fabric is not particularly limited as long as the effects of the present invention are not impaired, but in view of strength, flexibility, absorbency, etc. It is in the range of m ² to 60 g / m ² , preferably in the range of 10 g / m ² to 30 g / m ² . The basis weight of the nonwoven fabric as a whole is not particularly limited as long as the effects of the present invention are not impaired, but it is usually in the range of 10 g / m ² to 100 g / m ² , preferably in the range of 15 g / m ² to 75 g / m ² And more preferably in the range of 20 g / m ² to 50 g / m ² . Furthermore, the thickness of the non-woven fabric is not particularly limited as long as the effects of the present invention are not impaired, but it is usually in the range of 0.1 mm to 5 mm, preferably in the range of 0.5 mm to 3 mm, more preferably 0.8 mm to It is in the range of 2 mm.

In addition, the liquid-permeable sheet of the absorbent article to which the nonwoven fabric of the present invention is applied is not limited to the above-mentioned surface sheet, for example, even if it is an intermediate sheet etc. which are arranged between a surface sheet and an absorber. Good. Furthermore, the absorbent article to which the nonwoven fabric of the present invention is applied is not limited to the above-mentioned disposable diaper, and the nonwoven fabric of the present invention is applied to various absorbent articles such as (light) incontinence pad, sanitary napkin, panty liner, etc. can do.
In the present invention, the form of the non-woven fabric is not particularly limited. For example, the non-woven fabric may be in the form of a non-woven fabric in which the above-mentioned non-woven fabric is wound in a roll.

[Non-woven fabric roll]
Hereinafter, preferred embodiments of the nonwoven fabric roll of the present invention will be described in detail with reference to the drawings. Here, FIG. 8 is a perspective view of the nonwoven fabric roll 200 in which the nonwoven fabric 20 is wound up in a roll shape.
As shown in FIG. 8, in still another embodiment of the present invention, the nonwoven fabric roll 200 is formed by winding the nonwoven fabric 20 according to the above-described embodiment in a roll shape. The non-woven fabric roll 200 uses the non-woven fabric 20 in which the internal cotton is unlikely to come out to the outside even when physical load such as friction or vibration is applied, so the non-woven fabric 20 can be used for the above-described disposable It can be provided as a material adapted to high-speed production (that is, production under conditions in which physical load such as friction or vibration is likely to be applied) of an absorbent article such as diaper 1.

In the present invention, the nonwoven fabric roll is preferably a surface on which the first surface of the nonwoven fabric was in contact with the net-like support at the time of production, that is, the net surface. Thus, when the first surface of the non-woven fabric is a net surface having a relatively high fiber density, the non-woven fabric is unwound from the non-woven fabric roll when winding the non-woven fabric into a roll in the process of producing the non-woven fabric or in the process of producing the absorbent article. Even when non-woven fabrics overlapping in the thickness direction rub against each other, the first surface (net surface) having a high fiber density hardly changes the surface structure, and the cotton contained in the first fiber layer is on the first surface side It can be made difficult to get out of it.

The non-woven fabric or non-woven fabric roll of the present invention is not limited to the above-described embodiments and the like, and can be appropriately combined, substituted, changed and the like without departing from the object and the purpose of the present invention. Furthermore, in the present specification, the ordinal numbers such as "first" and "second" are used to distinguish the items to which the ordinal numbers are attached, and mean the order, priority, importance, etc. of each item. It is not something to do.

1 Disposable diapers (absorbent articles)
2 Surface sheet (liquid permeable sheet)
Reference Signs List 20 non-woven fabric 21 first fiber layer 22 second fiber layer 23 convex portion 231 top 23A convex portion region 24 concave portion 241 bottom portion 242 side wall portion 24A concave portion region 242A side wall portion region 200 nonwoven fabric roll 3 back sheet (liquid impervious sheet)
4 absorber 5 side sheet 6 telescopic member

Claims

A nonwoven fabric for a liquid-permeable sheet of an absorbent article, having a first surface and a second surface opposed in the thickness direction,
The non-woven fabric forms the first surface to be the non-skin-facing surface of the liquid-permeable sheet, and the first fiber layer containing cotton and a thermoplastic resin fiber and the skin-facing surface of the liquid-permeable sheet A plurality of projections formed of a second fiber layer forming a second surface, containing thermoplastic resin fibers and not containing cotton, and projecting in a direction from the first surface to the second surface; And a plurality of recesses recessed in a direction from the second surface toward the first surface,
Furthermore, the non-woven fabric has a protrusion region extending in the thickness direction from the second surface to the first surface of the protrusion, and the thickness direction from the second surface to the first surface of the recess. And a recessed area extending to the upper surface of the non-woven fabric, wherein the recessed area has a cotton content in the first fiber layer smaller than that of the raised area.
The concave portion has a bottom portion and a side wall portion extending from the bottom portion toward the convex portion, and the concave region is in the thickness direction from the second surface to the first surface of the side wall portion A nonwoven fabric according to claim 1, comprising the cotton fiber mass in the extending sidewall region.
The protrusion is a ridge extending in a first direction, and the recess is a groove extending in the first direction, adjacent to the ridge in a second direction orthogonal to the first direction. The non-woven fabric according to claim 2, wherein a fiber mass of cotton is present in the first fiber layer from the convex area to the concave area.
The cotton fiber lump existing from the convex area to the concave area has a second direction length of a part existing in the convex area in a second direction of a part existing in the concave area The nonwoven fabric according to claim 3, which is longer than the length.
The non-woven fabric according to any one of claims 2 to 4, wherein the cotton fiber mass is unevenly distributed near the first surface side in the thickness direction in the first fiber layer.
The nonwoven fabric according to any one of claims 2 to 5, wherein a fiber mass of the cotton is partially exposed from the first surface.
The nonwoven fabric according to claim 6, wherein the cotton has a flat cross-sectional shape in a part of fibers.
The cotton fiber mass has a mass portion in which cotton fibers are aggregated, and a diffusion fiber portion made of a plurality of cotton fibers extending in a surface direction from the mass portion toward the first surface side. The nonwoven fabric according to any one of 2 to 7.
9. The thermoplastic resin fiber contained in the second fiber layer has a fineness larger than the fineness of each of the thermoplastic resin fiber contained in the first fiber layer and the cotton. The nonwoven fabric as described in a term.
A nonwoven fabric roll for a liquid-permeable sheet of an absorbent article, wherein the nonwoven fabric according to any one of claims 1 to 9 is rolled up in a roll.
The nonwoven fabric roll according to claim 10, wherein the first surface of the nonwoven fabric is a net surface.