TWI763882B - Non-woven fabrics and non-woven fabric rolls for liquid-permeable sheets of absorbent articles - Google Patents

Abstract

The present invention provides a non-woven fabric for a liquid-permeable sheet of an absorbent article, which has a good feel to the skin, and which does not easily detach the inner cotton and does not easily impart a moist feeling to the wearer's skin. The nonwoven fabric (20) of the present invention is composed of a first fiber layer (21) and a second fiber layer (22), the first fiber layer (21) contains cotton (C) and thermoplastic resin fibers (F ₁ ), and the The second fiber layer (22) contains thermoplastic resin fibers (F ₂ ) and does not contain cotton, and the non-woven fabric ( 20 ) includes a plurality of convex portions ( 23 ) and a plurality of concave portions ( 24 ), and further, the non-woven fabric ( 20 ) It has a convex portion region (23A) and a concave portion region (24A), the convex portion region (23A) extending from the second surface (2b) to the first surface (2a) of the convex portion (23) in the thickness direction, the The recessed portion region (24A) extends from the second surface (2b) to the first surface (2a) of the recessed portion (24) in the thickness direction, and the recessed portion region (24A) is the cotton (24A) of the first fiber layer (21). The content of C) is smaller than that of the aforementioned convex region (23A).

Description

Non-woven fabrics and non-woven fabric rolls for liquid-permeable sheets of absorbent articles

The present invention relates to a nonwoven fabric used as a liquid-permeable sheet of absorbent articles such as disposable diapers and sanitary napkins, and a nonwoven fabric roll formed by winding the nonwoven fabric into a roll shape.

For absorbent articles such as disposable diapers and sanitary napkins, the use of non-woven fabrics containing cotton as a natural fiber is being studied as a material for liquid-permeable sheets such as topsheets in order to obtain a sense of security brought by natural materials.

For example, Patent Document 1 discloses a surface layer (non-woven fabric) of an absorbent article, the surface layer (non-woven fabric) of the absorbent article containing hydrophobic fibers and hydrophilic fibers such as cotton that are shorter than the hydrophobic fibers, and the aforementioned hydrophobic fibers are They are thermally fused to each other, at least a part of the hydrophilic fibers form an aggregate and are dispersed in the sheet, and at least a part of the hydrophilic fibers of the aggregate are fused to the surface of the hydrophobic fibers. The surface layer disclosed in Patent Document 1 can easily permeate the absorbent layer for a large amount of liquid, and easily retain in the surface layer for a small amount of liquid, thereby providing the wearer's skin with a moisturizing feel that is not easily imparted to the wearer's skin. Wear a tactile absorbent article. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2002-651

[The problem to be solved by the invention]

However, in a non-woven fabric such as the surface layer disclosed in Patent Document 1, that is, a non-woven fabric in which cotton is dispersed in the surface direction, if a concave-convex structure composed of a plurality of convex portions and concave portions is formed for the purpose of obtaining a good skin feel, etc., In the concave portion with a relatively thin thickness, the distance from the inside to the outside of the non-woven fabric is short. Therefore, the cotton dispersed inside the non-woven fabric is easy to fall off to the outside of the non-woven fabric due to physical loads such as friction or vibration, and when dispersed in the non-woven fabric. When the inner cotton absorbs and retains the excretion fluid such as urine discharged by the wearer, the excretion fluid retained by the cotton tends to ooze out onto the surface of the non-woven fabric due to the wearer's body pressure, etc. ), as a result, there is a possibility that a moist feeling may be imparted to the skin of the wearer.

Therefore, an object of the present invention is to provide a nonwoven fabric for a liquid-permeable sheet of an absorbent article, which has a good feel to the skin, and which does not easily give off the inner cotton and does not give a moist feeling to the wearer's skin. [Means of Solving Problems]

One aspect (aspect 1) of the present invention is a nonwoven fabric for a liquid-permeable sheet of an absorbent article, which has a first surface and a second surface opposite to each other in the thickness direction: the nonwoven fabric is composed of a first fiber layer. and a second fiber layer that forms the first surface as the non-skin-facing surface of the liquid-permeable sheet, and contains cotton and thermoplastic resin fibers, and the second fiber layer forms the first surface as the transparent sheet. The second surface of the skin-facing surface of the liquid sheet contains thermoplastic resin fibers and does not contain cotton; and the non-woven fabric includes a plurality of convex parts and a plurality of concave parts, and the plurality of convex parts are directed from the first surface to the above-mentioned The plurality of concave portions protrude in the direction of the second surface, the plurality of concave portions are concave from the second surface toward the first surface, and the nonwoven fabric further includes a convex portion region and a concave portion region, the convex portion region extending from the first surface of the convex portion. The second surface extends in the thickness direction from the first surface, the recessed region extends from the second surface to the first surface of the recessed portion in the thickness direction, and the recessed region is the cotton content of the first fiber layer. less than the aforementioned convex region.

The nonwoven fabric of this aspect is composed of a first fiber layer containing cotton and thermoplastic resin fibers, and a second fiber layer containing thermoplastic resin fibers and not containing cotton, and since it has the above-mentioned plural convex portions and plural concave portions, When the nonwoven fabric of this aspect is used in a liquid-permeable sheet (for example, a surface sheet, etc.) of an absorbent article, a good touch is exhibited by the plurality of convex portions and concave portions, the first fiber layer contains cotton , the first fiber layer is located at a position separated from the skin-opposing surface (ie, the second surface of the non-woven fabric) facing the wearer's skin (in other words, by the skin-opposing surface of the first fiber layer containing cotton The second fiber layer is interposed on the surface side), and as a whole, even if the cotton is not easily detached from the skin-opposing surface side of the liquid-permeable sheet (ie, the second surface side of the non-woven fabric) to the outside, and the hydrophilic cotton absorbs Moreover, the condition of excretory fluid such as urine discharged by the wearer is maintained, and the excretory fluid is not easily exuded to the skin-facing surface of the liquid-permeable sheet. Furthermore, the nonwoven fabric of this aspect has a convex region extending from the second surface to the first surface of the convex portion in the thickness direction, and a concave region extending from the second surface to the first surface of the concave portion. One surface extends in the thickness direction, and further, since the cotton content of the first fiber layer is smaller than that of the convex region, the concave region where the thickness is thin and is particularly prone to the above-mentioned cotton falling off or excretion leakage, except for reducing the first fiber layer. In addition to the possibility of the cotton in the fiber layer falling off to the outside, the amount of the excrement held by the cotton itself is also reduced, and the excretion becomes less likely to seep out to the skin-facing surface of the liquid-permeable sheet (that is, the nonwoven fabric). side 2). From the above, the nonwoven fabric of this aspect can provide a nonwoven fabric for a liquid-permeable sheet of an absorbent article, which has a good feel to the skin, and which does not easily give off the inner cotton, and which does not easily impart a moist feeling to the wearer's skin.

Furthermore, another aspect (aspect 2) of the present invention is the nonwoven fabric according to the above-mentioned aspect 1, wherein the concave portion has a bottom portion and a side wall portion extending from the bottom portion toward the convex portion, and the concave portion region is connected from the bottom portion to the convex portion. The second surface of the side wall portion extends from the first surface to the side wall portion region in the thickness direction, and contains the cotton fiber mass.

The nonwoven fabric of this aspect has the thinnest thickness in the recessed area and the bottom area where the above-mentioned cotton shedding or exudation of excretory fluid is most likely to occur (that is, the area extending from the second surface to the first surface of the bottom of the recessed portion in the thickness direction) region) adjacent to the above-mentioned side wall region region, the cotton is contained in the form of a fiber mass, and the fiber mass is more bulky than the state in which the fibers (cotton) exist in a dispersed state (that is, the state in which each fiber exists alone), and it is easy to Absorbs and retains excretory fluid. Therefore, the non-woven fabric in its original state containing the cotton fiber mass can more reliably prevent the cotton in the recessed area from falling off to the outside, and absorb and retain the excretory fluid preferentially in the cotton in the side wall area. The way of the fibrous mass, in particular, makes the exudation of the excretory fluid from the bottom area less prone to occur.

Still another aspect (aspect 3) of the present invention is the nonwoven fabric according to the above-mentioned aspect 2, wherein the convex portion is a mu portion extending in the first direction, and the concave portion is a groove portion that is perpendicular to the first direction. In the second direction, the groove portion is adjacent to the mu portion and extends in the first direction, and the cotton fiber mass is present in the first fiber layer from the convex portion region across the concave portion region.

In the nonwoven fabric of this aspect, the above-mentioned cotton fiber mass exists in the first fiber layer from the convex region to the concave region. Therefore, in the concave region where the fiber density is relatively high, the thermoplastic resin fibers in the first fiber layer can pass through. In addition, in the convex region where the fiber density is relatively low, when a physical load such as vibration is applied to the nonwoven fabric to move the fiber block, a small space for allowing the fiber block to move can be secured (in other words, , which can support the fiber mass of cotton while responding to physical loads such as vibration). Therefore, even in an environment where physical loads such as vibration are easily applied, the non-woven fabric of this aspect can more reliably prevent the cotton from falling off.

Still another aspect (Aspect 4) of the present invention is the nonwoven fabric according to the above-mentioned aspect 3, wherein the fiber mass of the cotton existing across from the convex region to the concave region is present in the convex region The length of the part in the second direction is longer than the length in the second direction of the part existing in the recessed region.

In the nonwoven fabric of this aspect, the length in the second direction of the portion existing in the convex portion region of the cotton fiber mass that spans from the convex portion region to the concave portion region of the nonwoven fabric of the aforementioned aspect 3 is greater than the length in the second direction of the portion existing in the concave portion region. Since the length in the second direction is longer, the cotton is less likely to fall off as in the nonwoven fabric of the above-mentioned aspect 3, and the excretory fluid (more specifically, the cotton fiber mass existing in the cotton fiber mass) can be removed. part of the convex region) preferentially absorbs and retains in the convex region, so that the exudation of the excretory fluid from the concave region can be more difficult to occur.

Still another aspect (aspect 5) of the present invention is the nonwoven fabric according to any one of the above-mentioned aspects 2 to 4, wherein, in the first fiber layer, the fiber lumps of the cotton are offset in the thickness direction near the second 1 side.

In the nonwoven fabric of this aspect, the above-mentioned cotton fiber lumps are biased toward the first surface side in the thickness direction of the first fiber layer. Therefore, when the nonwoven fabric of this aspect is used for the liquid-permeable sheet of an absorbent article, the cotton fiber lumps are present in the thickness direction. At a position further separated from the skin-facing surface of the liquid-permeable sheet (ie, the second surface of the nonwoven fabric), even if the cotton fiber mass holds the excretory fluid, it is more difficult to seep out to the skin-facing surface of the liquid-permeable sheet.

Still another aspect (Aspect 6) of the present invention is the nonwoven fabric according to any one of the above-mentioned aspects 2 to 5, wherein a part of the fiber mass of the cotton is exposed from the first surface.

A part of the fiber block of the nonwoven fabric of this aspect is exposed from the first surface. Therefore, when the nonwoven fabric of this aspect is used in the liquid-permeable sheet of an absorbent article, the non-skin-facing side of the liquid-permeable sheet (that is, the A part of the exposed fiber mass on the first surface of the nonwoven fabric becomes a bridge, and the excretory fluid can be easily moved to members such as an absorber located on the non-skin-opposing surface side of the liquid-permeable sheet. Thereby, the nonwoven fabric of this aspect can not only improve the absorbent performance of the absorbent article, but also make it more difficult to generate re-humidity, and thus can make it more difficult to impart a moist feeling to the skin of the wearer.

Still another aspect (aspect 7) of the present invention is the nonwoven fabric according to the above-mentioned aspect 6, wherein the cross-sectional shape of a part of the cotton-based fibers is a flat shape.

The nonwoven fabric of this aspect is the nonwoven fabric of the aforementioned aspect 6, and the cross-sectional shape of a part of the cotton fibers is flat. Therefore, when the nonwoven fabric of this aspect is used for the liquid-permeable sheet of an absorbent article, the difference between the liquid-permeable sheet and the liquid-permeable sheet Cotton fibers contained in a part of the fiber mass exposed on the non-skin-opposing surface can easily come into contact with members such as an absorber located on the non-skin-opposing surface side of the liquid-permeable sheet in a wider contact area, thereby making the excretory fluid easier to contact. Efficiently move to members such as absorbers.

Still another aspect (Aspect 8) of the present invention is the nonwoven fabric according to any one of the above-mentioned aspects 2 to 7, wherein the cotton fiber block has a block portion in which the cotton fibers are aggregated, and the cotton fibers The said block part expands in the surface direction toward the 1st surface side, and is a diffuser fiber part which consists of a plurality of cotton fibers which extend sideways.

In the nonwoven fabric of this aspect, the fiber block of the cotton has the specific structure of the block portion and the diffuser fiber portion. Therefore, the cotton fibers of the diffuser fiber portion and the thermoplastic resin fibers in the first fiber layer are entangled with each other, or protrude into the thermoplastic resin. The fixing effect is exhibited between the fibers of the resin fibers, and the fiber lumps of the cotton can be more reliably prevented from falling off from the first surface side. Furthermore, when the nonwoven fabric of this aspect is used for the liquid-permeable sheet of an absorbent article, the excretory fluid supplied to the skin-facing surface of the liquid-permeable sheet and passing through the thickness direction can be concentrated (dotted). ground) absorption and retention in the block portion of the above-mentioned cotton fiber block, and in the diffusion fiber portion, the excretory fluid held in the block portion faces the non-skin in the thickness direction while diffusing in the surface direction of the liquid-permeable sheet Since the surface side (that is, the first surface side of the nonwoven fabric) moves, the excretory fluid can be moved from a wider area to members such as the absorber, and the excretory fluid can be moved from the non-skin facing surface of the liquid-permeable sheet The backflow toward the skin-opposing surface side and the exudation (re-moisture) of the excretory fluid toward the skin-opposing surface of the liquid-permeable sheet are less likely to occur.

Still another aspect (Aspect 9) of the present invention is the nonwoven fabric according to any one of the above-mentioned aspects 1 to 8, wherein the thermoplastic resin fibers contained in the second fiber layer have a fineness higher than that of the first fiber layer. The respective finenesses of the thermoplastic resin fibers and the cotton contained in the fiber layer are larger.

In the nonwoven fabric of this aspect, the fineness of the thermoplastic resin fibers contained in the second fiber layer is larger than that of the thermoplastic resin fibers and cotton contained in the first fiber layer. Therefore, the relatively small fineness of the first fiber layer The thermoplastic resin fibers and cotton contained are easily entangled with the thermoplastic resin fibers contained in the first fiber layer or in the second fiber layer, so that the first fiber layer is caused by dissociation of the cotton and the thermoplastic resin fibers. Therefore, even if cotton is included as a constituent of the nonwoven fabric, excellent strength and shape retention can be exhibited. Furthermore, the inter-fiber distance of the thermoplastic resin fibers contained in the second fiber layer is relatively smaller than the inter-fiber distance between the thermoplastic resin fibers and cotton contained in the first fiber layer. Therefore, the first fiber layer The contained fibers (especially cotton) are less likely to fall off to the second surface side through the second fiber layer (that is, the cotton is less likely to fall off to the outside), and re-moisture is also less likely to occur.

Still another aspect (Aspect 10) of the present invention is 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 wound into a roll shape.

The non-woven fabric roll of this aspect uses a non-woven fabric (that is, the non-woven fabric of any one of the above-mentioned aspects 1 to 9) in which the cotton in the non-woven fabric does not easily fall off to the outside even if a physical load such as friction or vibration is applied. The nonwoven fabric is a material suitable for high-speed production of absorbent articles (that is, production under conditions where physical loads such as friction or vibration are easily applied) while suppressing the shedding of cotton.

Still another aspect (aspect 11) of the present invention is the nonwoven fabric roll according to the aforementioned aspect 10, wherein the first surface of the nonwoven fabric is a mesh surface.

In the nonwoven fabric roll of this aspect, the first surface of the nonwoven fabric has a relatively high fiber density. Therefore, when the nonwoven fabric is wound into a roll during the production process of the nonwoven fabric, or the nonwoven fabric is never rolled during the production process of the absorbent article. When the non-woven fabric is sent out, even if the non-woven fabrics overlapped in the thickness direction rub against each other, the surface structure of the first surface (mesh surface) with high fiber density is not easily changed, and the cotton contained in the first fiber layer is not easily removed from the first surface side. . [Effect of invention]

ADVANTAGE OF THE INVENTION According to this invention, the nonwoven fabric for a liquid-permeable sheet|seat of an absorbent article which has a favorable skin feel, does not easily fall off the inner cotton, and does not easily give a moist feeling to the wearer's skin can be provided.

Hereinafter, preferred embodiments of the nonwoven fabric of the present invention will be described in detail with reference to the drawings. In addition, in this specification, unless otherwise specified, "objects (for example, non-woven fabrics, absorbent articles, surface sheets, etc.) placed on a horizontal plane in an unfolded state, from the upper side in the vertical direction (objects) In the case of an absorbent article, the surface sheet side) is viewed in the thickness direction of the object", which is simply referred to as "planar view".

The various directions etc. used in this specification are as follows as long as there is no particular limitation. In this specification, the "longitudinal direction" refers to the "longitudinal direction of the length of a vertically long object (for example, an absorbent article, nonwoven fabric, etc.) when viewed from a plane", and the "width direction" refers to "the longitudinal direction when viewed from a plane." The short direction (short side direction) of the length of a long object", "thickness direction" means "the vertical direction for the object placed on the horizontal plane in the unfolded state", the long side direction, width direction and thickness The direction systems are in an orthogonal relationship to each other, respectively. In addition, in this specification, the "plane direction" refers to "the direction in which the plane of a substantially sheet-like object (for example, nonwoven fabric, absorbent article, surface sheet, etc.) when viewed from a plane extends (ie, the horizontal plane direction)", and the The plane direction and the thickness direction are in an orthogonal relationship with each other. In addition, in this specification, unless otherwise specifically limited, in the thickness direction of the absorbent article, "the side that is relatively proximal to the wearer's skin surface when the absorbent article is worn" is referred to as the "skin-opposing surface." side", and "the side farther from the skin surface of the wearer when the absorbent article is worn" is referred to as the "non-skin-opposite surface side". In addition, in this specification, "the surface of the skin-opposing surface side" and the "non-skin-opposing surface side" of the absorbent article and various members constituting the absorbent article (for example, the surface sheet, the absorber, the back sheet, etc.) surface", sometimes referred to as "skin-opposed surface" and "non-skin-opposed surface", respectively.

1 : is a top view of the disposable diaper 1 which uses the nonwoven fabric 20 as the surface sheet 2 in one Embodiment of this invention. Fig. 2 is a partial cross-sectional view of the disposable diaper 1 taken along the line II-II' in Fig. 1 . As shown in FIG. 1 , a disposable diaper 1 (an example of the “absorbent article” of the present invention) has a longitudinal direction L and a width direction W in a plan view, and further, a substantially central portion in the longitudinal direction L It has a substantially hourglass bell-shaped longitudinally elongated outer shape that narrows 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, as long as the length in the longitudinal direction L is longer than the length in the width direction W, various shapes can be adopted. Arbitrary elongated shape (for example, rectangle, oval, gourd, etc.) according to the application and the like.

Furthermore, as shown in FIG. 2, the disposable diaper 1 has, in the thickness direction T, as a main constituent member: a liquid-permeable nonwoven fabric 20 according to an embodiment of the present invention located on the skin-opposing surface side. Liquid-impermeable top sheet 2 (an example of the "liquid-permeable sheet" of the present invention); liquid-impermeable back sheet 3 positioned on the non-skin-opposite side; and liquid-absorbent absorbent positioned between the two sheets body 4. Furthermore, as shown in FIGS. 1 and 2 , the disposable diaper 1 further includes, as constituent members: a pair of liquid-impermeable side sheets 5 and 5 that form a leak-proof wall; The two end portions in the width direction W of the diaper 1 (that is, the left and right foot peripheral portions that are in contact with the wearer's thighs) expand and contract in the longitudinal direction L, respectively, and are made of a rubber thread or the like. , 6; connecting belts 7, 7 for connecting the abdomen-facing region and back-facing region of the disposable diaper 1 when worn; (not shown). That is, the disposable diaper 1 is a so-called tape-type disposable diaper. In addition, in the disposable diaper 1 as shown in FIG. 1 , the region located on the one end side in the longitudinal direction L in the lower part of FIG. The region on the other end side in the longitudinal direction L is a back facing region corresponding to the back (buttocks) of the wearer.

Furthermore, in the above-mentioned disposable diaper 1, the constituent members other than the topsheet 2 are not particularly limited as long as they can obtain the respective functions of various constituent members of the absorbent article, and any well-known in the field can be used. constituent components.

For example, the back sheet 3 is formed of a liquid-impermeable sheet arranged on the non-skin-facing surface side (the lower side of the absorber 4 in FIG. 2 ) of the disposable diaper 1 , It prevents the permeation of excretory fluid such as urine excreted by the wearer, and functions to prevent the excretory fluid from leaking into the wearer's underwear, clothing, or the like. In addition, the liquid-impermeable sheet forming the back sheet is one that does not permeate liquids such as excretory fluid, but preferably has a predetermined air permeability. When the back sheet has such breathability, moisture released from the absorber (specifically, moisture from excretion liquid absorbed and held in the absorber) is easily released to the absorbent article through the back sheet. Therefore, moisture is less likely to accumulate inside the absorbent article or between the absorbent article and the wearer's skin surface.

The liquid-impermeable sheet that can be used as the back sheet is not particularly limited, and for example, any hydrophobic thermoplastic resin fiber (for example, polyolefin-based fibers such as polyethylene (PE) and polypropylene (PP); Polyester fibers such as ethylene phthalate (PET); hydrophobic non-woven fabrics formed of core-sheath type and other composite fibers, etc.); air-permeable resin films formed of hydrophobic thermoplastic resins such as PE or PP; An arbitrary liquid-impermeable sheet, such as a laminated body of non-woven fabric, a laminated non-woven fabric such as SMS non-woven fabric, and the like is bonded to the resin film.

The thickness, basis weight, outer shape, etc. of the back sheet are not particularly limited as long as the effects of the present invention are not inhibited, and any thickness, basis weight, outer shape, etc. can be adopted in accordance with the desired leak-proof performance, air permeability, strength, etc. . Moreover, in the disposable diaper 1 described above, the back sheet 3 is in a state where the absorber 4 is sandwiched between the back sheet 3 and the top sheet 2 , and the peripheral portion is joined to the top sheet 2 .

Furthermore, in the disposable diaper 1 described above, the absorber 4 is disposed between the top sheet 2 and the back sheet 3, and can absorb and hold excretory fluid such as urine that has passed through the top sheet 2. It is formed of a liquid-absorbent absorbent member. As shown in FIG. 1 , the absorber 4 extends over a wide range in the longitudinal direction L of the disposable diaper 1 in a plan view, and further, a substantially central portion in the longitudinal direction L has a direction W in the width direction. It has an approximately hourglass bell-shaped elongated outer shape narrowed on the inner side. In addition, the absorption system of the absorbent article to which the nonwoven fabric of the present invention is applied is not limited to this form, and any longitudinal shape (eg, rectangle, ellipse, gourd, etc.) can be adopted according to various applications.

The absorptive member that can be used as an absorber is not particularly limited as long as it can absorb and retain excretion fluids such as urine. An absorbent core composed of a material, and at least one liquid-permeable core wrap sheet (eg, tissue paper composed of hydrophilic cellulose fibers) covering the outer peripheral surface of the absorbent core, etc. Here, as water-absorbing fibers, for example, cellulose-based fibers and the like can be used, and more specifically, wood pulp obtained by using conifers or broad-leaved trees as raw materials; non-wood pulps such as kenaf, hemp, and cotton; rayon , fibril rayon and other regenerated cellulose; semi-synthetic cellulose such as acetate and triacetate can be used. In addition, as superabsorbent polymers, for example, starch-based superabsorbent polymers; synthetic polymer-based superabsorbent polymers (so-called "SAP") such as sodium acrylate copolymers and other granular materials.

The thickness, basis weight, etc. of the absorber are not particularly limited as long as the effects of the present invention are not inhibited, and any thickness, basis weight, etc. can be adopted in accordance with desired absorption performance, flexibility, and the like. In addition, the thickness, basis weight, etc. of the absorber may be constant over the entire surface direction of the absorber, or may be partially different. In addition, the absorbent article to which the nonwoven fabric of the present invention is applied may not include such an absorber as long as constituent members other than the absorber (for example, a topsheet or the like) have predetermined liquid absorbency.

In addition, in the above-mentioned disposable diaper 1, the absorber 4 is bonded to the surface sheet 2 on the skin-facing side, and the non-skin-facing side and the back sheet, respectively, by any bonding means such as a hot-melt adhesive. 3 Engage.

In addition, in the disposable diaper 1 described above, the liquid-permeable topsheet 2 is disposed on the skin-opposing surface side (upper side of the absorber 4 in FIG. 2 ) as shown in FIG. The liquid-permeable sheet is formed as a sheet, and the liquid-permeable sheet has the function of rapidly moving excretion fluid such as urine discharged from the wearer to the absorber 4. Furthermore, in the above-mentioned disposable diaper 1, the liquid-permeable sheet is formed by using this liquid-permeable sheet. The nonwoven fabric 20 of one embodiment of the invention. In addition, in the above-mentioned disposable diaper 1, the surface sheet 2 is as shown in FIG. 1, and has an elongated rectangular outer shape in the longitudinal direction L in a plan view. In the nonwoven absorbent article to which the present invention is applied, It is not limited to this aspect, and the surface sheet can take any external shape according to various applications and the like.

Hereinafter, the nonwoven fabric 20 according to one embodiment of the present invention will be described in further detail with reference to the drawings. Here, Fig. 3 is a partial perspective view of a 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. 3 .

As shown in FIGS. 3 and 4 , the nonwoven fabric 20 of the present embodiment has a first direction D ₁ corresponding to the longitudinal direction L of the disposable diaper 1 , and a width direction W corresponding to the disposable diaper 1 . Corresponding second direction D ₂ ; the thickness direction T orthogonal to these directions, and has a first surface 2a and a second surface 2b opposite to each other in the thickness direction T. As shown in FIG. Furthermore, as shown in FIGS. 3 and 4 , the nonwoven fabric 20 of the present embodiment is constituted by a first fiber layer 21 and a second fiber layer 22, and the first fiber layer 21 is formed as the disposable diaper 1. The first surface 2a of the non-skin-opposing surface of the top sheet 2 (liquid-permeable sheet) contains cotton C and thermoplastic resin fibers F ₁ , and the second fiber layer 22 forms the skin-opposing surface of the top sheet 2 . The second surface 2b contains thermoplastic resin fibers F ₂ and does not contain cotton; further, it includes: a plurality of convex portions 23 protruding from the first surface 2a toward the second surface 2b; and from the second surface 2b toward the first The plurality of concave portions 24 recessed in the direction of the surface 2a. Furthermore, as shown in FIG. 4 , the non-woven fabric 20 has a convex region 23A and a concave region 24A, and the convex region 23A is tied to each of the plurality of convex portions 23 from the second surface 2 b to the first surface 2 a of the convex portion 23 . The concave portion region 24A extends in the thickness direction T, and the concave portion region 24A extends from the second surface 2b to the first surface 2a of the concave portion 24 in each of the plurality of concave portions 24 in the thickness direction T. The concave portion region 24A is the first fiber layer 21 The content of cotton C is less than that of the convex region 23A.

In this way, the nonwoven fabric 20 is composed of the first fiber layer 21 containing the cotton C and the thermoplastic resin fibers F ₁ , and the second fiber layer 22 containing the thermoplastic resin fibers F ₂ and not containing the cotton, and has a plurality of the above-mentioned The convex portion 23 and the plurality of concave portions 24, therefore, the plurality of convex portions 23 and the concave portions 24 exhibit a good touch to the skin, and the surface sheet 2 of the disposable diaper 1 is positioned away from the skin facing the disposable diaper 1. The first fiber layer 21 at the position of the surface (that is, the second surface 2b of the nonwoven fabric 20) contains cotton C (in other words, the second fiber layer 22 is interposed on the skin-opposing surface side of the first fiber layer 21 containing cotton C). ), as a whole, the cotton C does not easily fall off from the skin-opposing surface side of the topsheet 2 (ie, the second surface 2b side of the non-woven fabric 20 ) to the outside, and even if the hydrophilic cotton C absorbs and maintains the wearer’s Even in the case of excretion such as urine, the excretory fluid hardly oozes out to the skin-facing surface of the top sheet 2 . In addition, the nonwoven fabric 20 has a convex portion region 23A extending from the second surface 2b to the first surface 2a of the convex portion 23 in the thickness direction T, and a concave portion region 24A extending from the above-described convex portion region 24A. The concave portion 24 extends from the second surface 2b to the first surface 2a in the thickness direction T, and the concave portion region 24A has a smaller content of cotton C in the first fiber layer 21 than the convex portion region 23A. In the recessed region 24A where the above-mentioned shedding of the cotton C or exudation of the excretory fluid occurs, the possibility of the cotton C in the first fiber layer 21 falling off to the outside is reduced, and the amount of the excretory fluid retained by the cotton C itself is also reduced. This excretion liquid is made difficult to ooze out on the skin-facing surface of the top sheet 2 (that is, on the 2nd surface 2b of the nonwoven fabric 20). Therefore, the nonwoven fabric 20 of the present embodiment has a good feel to the skin, and the cotton C inside does not easily fall off, and the surface sheet 2 (liquid-permeable sheet) that does not easily impart a moist feeling to the wearer's skin can be formed.

Here, in this specification, the cotton content of each of a convex part area|region and a concave part area|region can be obtained as follows, for example. That is, (1) the initial mass (g) of the sample is measured after cutting out a sample of the target region from a nonwoven fabric dried at 105° C. for 1 hour in advance. (2) Immerse the sample in 70% sulfuric acid for 1 hour to dissolve the cotton. (3) The sample immersed in sulfuric acid was washed with about 6 liters of water while being sucked 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, the mass (g) of the sample after treatment was measured. (5) Subtract the processed mass of the sampling from the initial mass of the above sampling, thereby calculating the cotton-containing mass (g) of the sampling, and further, converting the obtained cotton-containing mass into the mass per unit plane viewing area, thereby enabling The above cotton content is obtained. Therefore, the magnitude relationship of the cotton content in each of the above-described convex region and recessed region can be obtained by comparing the cotton content in each region after obtaining the cotton content. In addition, the measurement of the said cotton content was carried out at 5 different places arbitrarily, and the average value was used.

In addition, in this specification, a convex part and a concave part are divided as follows. That is, as shown in FIG. 4 , when the first surface of the non-woven fabric is placed on the lower side and the non-woven fabric is placed on a horizontal surface, the height of the second surface is the “highest part” of the convex portion, and the height of the second surface is Taking the lowest part as the "deepest part" of the concave part, at the position where the difference d in height between the highest part and the deepest part is divided into two equal parts (that is, the distance from the highest part and the deepest part in the thickness direction is d/2 The part that protrudes further upward than the enlarged virtual reference horizontal plane P _B is the "convex part", and the part which is more recessed to the lower side is the "concave part". In addition, the “top portion” of the convex portion (refer to the “top portion 231” in FIG. 4 ) described later means that the distance in the thickness direction from the highest portion including the highest portion is the height of the entire convex portion (ie, d/2). The part within 3% of the "bottom" of the recess (refer to "bottom 241" in Fig. 4 ), including the deepest part and the distance in the thickness direction from the deepest part, refers to the depth of the entire recess (that is, d/ 2) the part within 3%. Furthermore, as shown in FIG. 4 , in this specification, a region extending in the thickness direction from the second surface to the first surface of the convex portion is referred to as a “convex region”, and the region from the second surface to the first surface of the concave portion is referred to as a “convex region”. A region where one surface extends in the thickness direction is referred to as a "recessed region".

Furthermore, as shown in FIG. 3 , in the above-mentioned nonwoven fabric 20, a plurality of convex portions 23 are formed as a plurality of mu portions extending continuously in the _first direction D1, and a plurality of concave portions 24 are formed in a direction perpendicular to the _first direction D1. The second direction D ₂ is adjacent to the mu portions (that is, located between the mu portions adjacent to the second direction D ₂ ), and is formed as a plurality of groove portions extending continuously in the first direction D ₁ . Since the non-woven fabric 20 has such a specific groove structure, it has excellent cushioning properties in the thickness direction T, can exhibit a good touch to the skin, and can also enable the excretory fluid to extend along the _first direction D1 (that is, the groove portion) along the groove portion. , the surface sheet 2 spreads in the longitudinal direction L), and can bring excellent absorption performance to the disposable diaper 1 after use.

In addition, in the present invention, the uneven structure of the nonwoven fabric (that is, the structure having a plurality of convex parts and concave parts) is not limited to the mu groove structure like the above-mentioned embodiment, and any one can be used as long as it can exhibit a good skin feel. Concave and convex structure. As such a concavo-convex structure, for example, a concavo-convex structure composed of a plurality of rows of convex portions and a plurality of rows of concave portions, the plurality of rows of convex portions extending intermittently in the first direction and arranged in the second direction, and the plurality of rows of concave portions can be mentioned, for example Intermittently extending in the first direction between adjacent convex portions in the second direction; a concave-convex structure composed of a plurality of hemispherical or cylindrical convex portions and a plurality of concave portions located between adjacent convex portions Wait.

In the present invention, the specific structure of the convex portion and concave portion of the non _- woven fabric is not particularly limited as long as it can exhibit a good feel to the skin. The distance in the thickness direction) is in the range of 0.1mm to 3.0mm, the depth of the concave portion (that is, the distance in the thickness direction from the above-mentioned virtual reference level P _B to the deepest part) is in the range of 0.1mm to 3.0mm, and further, a plurality of The pitch of each convex portion (that is, the interval between the highest portions of two adjacent convex portions) is in the range of 0.5 mm to 5.0 mm. In addition, when the uneven structure of the nonwoven fabric is a mu groove structure, the width of the convex portion (that is, the length in the second direction of the portion where the length of the convex portion in the second direction becomes the longest) is, for example, in the range of 0.1 mm to 5.0 mm. The width of the concave portion (that is, the length in the second direction of the portion where the length of the concave portion in the second direction becomes the longest) is, for example, in the range of 0.1 mm to 5.0 mm. In addition, the nonwoven fabric in a non-pressurized state can be enlarged and observed by a magnifying observation means such as a scanning electron microscope, and the pitch and width of the convex portions and concave portions can be measured from a plan photograph or plan image thereof.

Moreover, in the said embodiment, the nonwoven fabric 20 has the substantially flat surface structure which is the 1st surface 2a which is the non-skin facing surface of the top sheet 2. Therefore, the nonwoven fabric 20 can secure a wider contact area with the absorber 4 disposed on the non-skin-opposing surface side of the topsheet 2, and can more efficiently and reliably move the excretory fluid passing through the topsheet 2 to the absorber 4. Furthermore, if the first surface 2a of the non-woven fabric 20 has such a substantially flat surface structure, since a sufficient thickness can be secured in the convex region 23A, there is an advantage that the cotton C contained in the first fiber layer 21 is less likely to fall off. .

In addition, in the present invention, the surface structure of the first surface of the non-woven fabric is not limited to this aspect. For example, the first surface of the non-woven fabric may have a portion corresponding to the convex portion on the second surface side in the thickness direction facing the first surface. 2-sided concave surface structure. When the first surface of the nonwoven fabric has such a surface structure, the recessed portion becomes a void portion toward the second surface side, and in addition to exhibiting better cushioning properties, the void portion serves as a space between the topsheet and the absorber. The function of the partition wall also reduces the contact area with the absorber, so the excretory fluid absorbed and held by the absorber is less likely to seep out to the skin-opposite surface of the surface sheet (ie, less likely to re-moisture).

The method for forming the above-mentioned concave-convex structure on the nonwoven fabric is not particularly limited, and for example, a method of continuously blowing gas (for example, air, etc.) to the fiber web before forming the nonwoven fabric (hereinafter, also referred to as "gas blowing method") can be used. ”) or a method using gear machining (hereinafter, also referred to as “gear machining method”), or an arbitrary shaping method such as a method using vacuum forming or compression forming. Among them, the uneven structure is formed, and the cotton contained in the first fiber layer is more likely to be uneven (that is, the content of cotton contained in the first fiber layer is easily controlled so that the content of the concave area is higher than that of the convex area. The content is less) From this point of view, the gas injection method is better.

Hereinafter, each fiber layer constituting the nonwoven fabric of the present invention will be described in more detail using the nonwoven fabric 20 of the above-described embodiment.

[1st fiber layer] In the nonwoven fabric of the present invention, the first fiber layer forms the first surface of the non-skin-facing surface of the liquid-permeable sheet, which is an absorbent article to which the nonwoven fabric is applied, and is composed of a fiber layer containing cotton and thermoplastic resin fibers. . The cotton contained in the first fiber layer is not particularly limited, and for example, cotton having a fineness in the range of 1.0 dtex to 15 dtex and a fiber length in the range of 5 mm to 40 mm can be used. Among them, when the first fiber layer and the second fiber layer are layered with a cotton system with a fiber length of 20 mm or more, a part of the cotton fiber tends to protrude into the second fiber layer, and further, the cotton that protrudes into the second fiber layer The fibers are used as bridges between the first fiber layer and the second fiber layer, and the liquid permeability of the entire nonwoven fabric can be improved, so it can be used appropriately. In addition, a blended cotton in which cotton with a fiber length of 20 mm or more (hereinafter, referred to as "long-fiber cotton") and cotton with a fiber length of 10 mm or less (hereinafter, also referred to as "short-fiber cotton") is mixed. In addition to improving the liquid permeability of the non-woven fabric, the long-fiber cotton can increase the bulkiness of the non-woven fabric by the short-fiber cotton, so it is particularly suitable.

The cotton content of the first fiber layer is not particularly limited, but from the viewpoint of water absorption, water retention, softness, etc., for example, it is in the range of 1 mass % to 70 mass %, preferably 2 mass % to 30 mass % In the range. Furthermore, in the present invention, the cotton contained in the first fiber layer of the nonwoven fabric must be distributed in the first fiber layer so that the content of the concave region is smaller than the content of the convex region. If the cotton is so unevenly distributed in the first fiber layer, the possibility of the cotton falling off from the first and second surfaces of the concave region where the thickness is thin is reduced, and the amount of the excretory fluid held by the cotton itself is also reduced. The excretion fluid does not easily seep out onto the surface of the non-woven fabric.

As described above, the means for dispersing the cotton in the first fiber layer is not particularly limited, and for example, the above-mentioned gas blowing method can be used. Specifically, a second fiber web composed of thermoplastic resin fibers for the second fiber layer is superimposed on a first fiber web in which cotton is substantially uniformly dispersed and mixed with the thermoplastic resin fibers for the first fiber layer. As a laminated fiber web, gas (for example, air, etc.) of a predetermined temperature and a predetermined pressure is sprayed from a plurality of injection ports while conveying the laminated fiber web onto the surface of the laminated fiber web on the second fiber web side (that is, the second fiber web). 2 sides), whereby the fibers in each fiber web and between the fiber webs are intertwined with each other and a plurality of concave portions are formed in the laminated fiber web, and in the area below the concave portion (that is, the concave portion area), the first fiber After the cotton contained in the web is blown or moved to the lower side of the convex portion adjacent to the concave portion (that is, the convex portion region) side (that is, after the cotton contained in the first fiber web is offset), the The laminated fiber web is conveyed to a heating device of a hot air system, and the thermoplastic resin fibers are used to fuse the fibers in and between the fiber webs to each other to obtain a first fiber layer composed of the above-mentioned cotton. and a non-woven fabric composed of a second fiber layer that does not contain cotton. According to the means using this gas blowing method, it is possible to easily achieve the localization of the cotton contained in the first fiber layer by simply adjusting the pressure of the gas to be blown onto the laminated fiber web (the injection pressure) and the injection conditions such as the injection diameter. Therefore, it is particularly suitable for use.

In addition, as another means of making the above-mentioned cotton uneven in the first fiber layer, for example, the above-mentioned gear processing method can be used. Specifically, the first fiber web and the second fiber web composed of thermoplastic resin fibers are preliminarily overlapped to form a laminated fiber web, and then both sides of the laminated fiber web are sandwiched by a pair of gear processing rolls. By partially pressing the portion with a small amount of cotton blended, a nonwoven fabric composed of the above-mentioned first fiber layer where the cotton is concentrated and the second fiber layer not containing cotton can be obtained while forming a plurality of concave portions in the laminated fiber web. .

Furthermore, in the present invention, the cotton contained in the first fiber layer is preferably dispersed in a matrix composed of an aggregate of thermoplastic resin fibers in the form of an aggregate formed by close aggregation of individual cotton fibers, that is, a fiber mass. Here, FIG. 5 is a schematic view of a model of the form of the constituent fibers of the nonwoven fabric 20 in the cross-sectional view of FIG. 4 , and FIG. 6 is an enlarged view of a portion surrounded by line VI of FIG. 5 .

As shown in FIG. 5 , the nonwoven fabric 20 is a cotton fiber block CB dispersed in a matrix composed of an aggregate of thermoplastic resin fibers F1 in the _first fiber layer 21 . In this way, when the cotton fiber lumps are dispersed in the first fiber layer of the non-woven fabric, even if the absorber is located on the non-skin-facing surface side of the surface sheet (liquid-permeable sheet) formed of the non-woven fabric, the The excretory fluid held by the body is released as moisture, and the released moisture can still be absorbed in a concentrated (point-like) manner and retained in the cotton fiber mass in the first fiber layer. The released moisture (excretion fluid) is less likely to ooze out to the skin-facing surface of the surface sheet.

Furthermore, in the nonwoven fabric 20 described above, the concave portion 24 has a bottom portion 241 and a side wall portion 242 extending from the bottom portion 241 toward the convex portion 23 as shown in FIGS. 4 and 5 . The fiber block CB of the above-mentioned side wall portion 242A extends in the thickness direction T from the second surface 2b to the first surface 2a of the side wall portion 242. In this way, the nonwoven fabric 20 contains the cotton C in the form of a fiber mass CB in the side wall region 242A, which is the thinnest even in the recessed region 24A, and is most likely to fall off or excrete the cotton C. The bottom region 241A where the liquid seeps out (that is, the region extending from the second surface 2b of the bottom 241 of the recessed portion 24 to the first surface 2a in the thickness direction T) is adjacent. C) The non-woven fabric 20 containing the cotton fiber block CB can more reliably suppress the concave part because it is easy to absorb and retain the excretory fluid in addition to the form existing in a dispersed state (that is, the form in which each fiber exists alone). The cotton C in the area 24A falls off to the outside, and the excretory fluid preferentially absorbs and retains the cotton fiber mass CB in the side wall area 242A, in particular, the exudation of the excrement fluid from the bottom area 241A is less likely to occur.

In addition, in this specification, as shown in FIG. 4, the side wall part of a recessed part means the part which exists extended from the bottom part of a recessed part to the said virtual reference horizontal plane _PB (namely, to the boundary of a convex part and a recessed part).

Moreover, in the said nonwoven fabric 20, as shown in FIG. 5, the fiber block CB of cotton exists in the 1st fiber layer 21, spanning from the said convex part area|region 23A to 24 A of concave part area|regions. In this way, if the cotton fiber mass CB exists in the first fiber layer 21 from the convex region 23A across the concave region 24A, in the concave region 24A with a relatively high fiber density, the fibers in the first fiber layer 21 can be formed. _The thermoplastic resin fibers F1 and the like can surely support the cotton fiber block CB, and in the convex region 23A where the fiber density is relatively low, when a physical load such as vibration is applied to the nonwoven fabric 20 to move the fiber block CB, it is possible to ensure that the fiber block CB can be moved. The tiny space that allows the movement of the fiber block CB (in other words, the fiber block CB that can support the cotton while responding to physical loads such as vibration), the nonwoven fabric 20 described above can be more easily applied even in an environment where a physical load such as vibration is easily applied. The shedding of the cotton C is surely made difficult to occur. In addition, regarding the fiber densities of the above-mentioned convex portion regions and concave portion regions, in general, if a concavo-convex structure is formed on a fiber web having an equal fiber density in the plane direction, the fiber density becomes relatively high in the concave portion regions where the thickness becomes thinner. The fiber density is relatively low in the convex portion region where the thickness is maintained (in other words, the thickness is relatively high).

Furthermore, in the nonwoven fabric 20 described above, the cotton fiber mass CB existing from the convex region 23A across the concave region 24A is, as shown in FIG. 5 , the length in the _second direction D2 of the portion existing in the convex region 23A It is longer than the length in the second direction D ₂ of the portion existing in the recessed region 24A. In this way, the length of the cotton fiber block CB existing across the concave area 24A from the convex area 23A of the nonwoven fabric 20 in the _second direction D2 in the part existing in the convex area 23A is longer than that in the concave area 24A. If the length of part of the _second direction D2 is longer, the shedding of the cotton C is less likely to occur as described above, and the excretory fluid (more specifically, by the fibers existing in the cotton) can also be released by the cotton fiber mass CB. The portion of the convex region 23A of the block CB is preferentially absorbed and held in the convex region 23A, so that the exudation of the excretory fluid from the concave region 24A is less likely to occur.

In addition, the length in the second direction of the part existing in each region of the fiber mass can be measured by measuring the length in the second direction of the part existing in the region by, for example, further magnifying the cross section of the region to be observed with a scanning electron microscope. and obtained.

In addition, in the present invention, it is preferable that the fiber mass of the cotton is biased toward the first surface side in the thickness direction in the first fiber layer. In this way, if the cotton fiber lumps are on the side closer to the first surface in the thickness direction in the first fiber layer, when the nonwoven fabric is used in the liquid-permeable sheet of an absorbent article, the cotton fiber lumps are present in the liquid-permeable sheet further from the liquid-permeable sheet. At the position where the skin-facing surface (ie, the second surface of the non-woven fabric) is separated, even if the cotton fiber mass holds the excretory fluid, it is difficult to further ooze out to the skin-facing surface of the liquid-permeable sheet.

Furthermore, in the above-mentioned nonwoven fabric 20, as shown in FIGS. 5 and 6, a part of the cotton fiber block CB is exposed from the first surface 2a of the nonwoven fabric 20 (refer to the “exposed portion CBd” of the fiber block CB in _FIG . 6). . In this way, when a part of the cotton fiber mass CB is exposed from the first surface 2a, the fiber mass exposed from the non-skin-opposing surface (that is, the first surface 2a of the nonwoven fabric 20) of the surface sheet 2 formed of the nonwoven fabric 20 A part of the CB (more specifically, as shown in FIG. 6 , the cotton fibers C _d contained in the exposed part CB _d of the fiber block CB) form a bridge, and the excretory fluid can easily move to the non-skin pair located on the surface sheet 2 . The absorber 4 on the face side. In this way, the non-woven fabric 20 can further improve the absorbency of the disposable diaper 1, and can also make it less likely to generate re-humidity, so that it is more difficult to impart a moist feeling to the wearer's skin.

In addition, when a part of the fiber block of ground cotton is exposed from the 1st surface in this way, it is preferable that the cross-sectional shape of a part of the fiber of the cotton is a flat shape. When the cross-sectional shape of a part of the cotton fiber is flat, when the nonwoven fabric is used in the liquid permeable sheet of an absorbent article, the fibers exposed from the non-skin-opposing surface of the liquid permeable sheet (ie, the first surface of the nonwoven fabric) Cotton fibers contained in a part of the block (refer to "cotton fibers C _d " contained in the exposed portion CB _d in FIG. 6 ) easily come into contact with the non-skin-opposing surface side of the liquid-permeable sheet with a wider contact area. Absorber and other members, the excretory fluid can be moved more efficiently to the absorber and other members.

Furthermore, in the nonwoven fabric of the present invention, it is particularly preferable that the cotton fiber block has a specific structure having a block portion and a diffuser fiber portion, the block portion is formed by agglomeration of cotton fibers, and the diffuser fiber portion is directed from the block portion by the side. The first surface side is composed of a plurality of cotton fibers extending while expanding in the surface direction. Here, Fig. 7 is a view corresponding to Fig. 5 of a nonwoven fabric 20' according to another embodiment of the present invention. In addition, the structure other than the structure which differs from the nonwoven fabric 20 of the said embodiment is basically the same as that of the said embodiment, and a description is abbreviate|omitted.

As shown in FIG. 7, in the nonwoven fabric 20' of another embodiment of the present invention, the fiber block CB of the cotton contained in the first fiber layer 21 has a specific structure having a block part BP and a diffusion fiber part DP, and the block part BP has a specific structure. The fibers of the cotton C are aggregated, and the diffusion fiber portion DP is composed of a plurality of fibers of the cotton C extending from the block portion BP toward the first surface 2a side while expanding in the surface direction. In this nonwoven fabric 20', since the cotton fiber block CB has a specific structure having the block portion BP and the diffusion fiber portion DP, the cotton fibers of the diffusion fiber portion DP and the thermoplastic resin fibers F1 in the _first fiber layer 21 are mutually By being entangled or inserted between the fibers of the thermoplastic resin fiber F1 to exert _a fixing effect, the above-mentioned cotton fiber block CB can be more reliably prevented from falling off from the first surface 2a side. Furthermore, the non-woven fabric 20' can absorb and hold the excretory fluid supplied to the skin-opposing surface of the surface sheet 2 formed of the non-woven fabric 20' and passing through the thickness direction T in a concentrated (point-like) manner. The block portion BP of the cotton fiber block CB and the diffusion fiber portion DP move to the non-skin-opposing surface side in the thickness direction T while diffusing the excretory fluid held in the block portion BP in the surface direction of the topsheet 2 (that is, on the first surface 2a side of the nonwoven fabric 20 ′), the excretory fluid can be moved from a wider area to the absorber 4 , and the excretory fluid can be less easily generated from the non-skin-opposing surface of the topsheet 2 . The backflow from the side to the skin-opposite surface side makes it more difficult for the excretory fluid to ooze out (re-moisture) to the skin-opposite surface of the top sheet 2 .

Next, the thermoplastic resin fibers contained in the first fiber layer will be described. In the present invention, the thermoplastic resin fibers contained in the first fiber layer are not particularly limited as long as they are fibers composed of a thermoplastic resin, and examples of the thermoplastic resin include polyethylene (PE), polypropylene ( Olefin resins such as PP), ethylene-vinyl acetate copolymer (EVA); polyester resins such as polyethylene terephthalate (PET) and polylactic acid (PLA); polyamide resins such as 6-nylon, etc. Well-known resins may be used alone, or two or more kinds of resins may be used in combination. Further, the fiber structure made of such thermoplastic resin is not particularly limited, and examples thereof include core-sheath fibers such as PET/PE, side-by-side fibers, and conjugate fibers such as island/sea fibers; hollow fibers; Fibers with irregular cross-sections such as Y-shaped and C-shaped fibers, etc., may be used alone, or two or more kinds of fibers may be used in combination.

The fineness of the thermoplastic resin fibers contained in the first fiber layer is not particularly limited, but is usually within the range of 0.6 dtex to 8.8 dtex from the viewpoint of the strength, softness, skin feel, and liquid permeability of the nonwoven fabric, preferably In the range of 1.1dtex~4.6dtex. In addition, the fineness of the thermoplastic resin fibers contained in the first fiber layer is preferably smaller than the fineness (fiber diameter) of the thermoplastic resin fibers contained in the second fiber layer described later. In this way, if the fineness of the thermoplastic resin fibers contained in the first fiber layer is smaller than that of the thermoplastic resin fibers contained in the second fiber layer, the thermoplastic resin fibers with the small fineness contained in the first fiber layer are the same as The cotton contained in the first fiber layer or the thermoplastic resin fibers contained in the second fiber layer are easily entangled with each other, so that the split of the first fiber layer or the inter-fiber layers due to the dissociation of the cotton and the thermoplastic resin fibers are less likely to occur. The interlayer peeling, even if the non-woven fabric contains cotton as a constituent, it can still exert excellent strength or shape retention.

In addition, the fiber length of the thermoplastic resin fibers contained in the first fiber layer is not particularly limited as long as the effect of the present invention is not hindered, but is usually 20 mm to 100 mm in terms of the strength, flexibility, and liquid permeability of the nonwoven fabric. , preferably in the range of 30mm~65mm. The thermoplastic resin fibers may also be subjected to a hydrophilization treatment, and examples of the hydrophilization treatment include treatment with a surfactant or a hydrophilic agent (for example, mixing a surfactant into the fiber, applying a surfactant to the fiber, etc.) surface, etc.) etc.

In the present invention, the content of the thermoplastic resin fibers contained in the first fiber layer is not particularly limited as long as the effects of the present invention are not inhibited, and from the viewpoint of the strength and flexibility of the nonwoven fabric, for example, it is 30% by mass to 99% by mass. , preferably within the range of 70% by mass to 98% by mass. In addition, the first fiber layer may contain fibers other than cotton and thermoplastic resin fibers, optional additives, and the like within a range that does not inhibit the effects of the present invention.

[2nd fiber layer] Next, the second fiber layer constituting the nonwoven fabric of the present invention will be described. In the nonwoven fabric of the present invention, the second fiber layer forms the second surface of the skin-facing surface of the liquid-permeable sheet that is an absorbent article to which the nonwoven fabric is applied, and is constituted by a fiber layer containing thermoplastic resin fibers and not containing cotton . The thermoplastic resin fibers contained in the second fiber layer are not particularly limited as long as they are fibers composed of a thermoplastic resin, but fibers composed of a hydrophobic thermoplastic resin, that is, fibers composed of a hydrophobic thermoplastic resin Fiber is better. If the second fiber layer forming the second surface of the nonwoven fabric (that is, the skin-facing surface of the liquid-permeable sheet of the absorbent article to which the nonwoven fabric is applied) is composed of such hydrophobic thermoplastic resin fibers, there is a direct contact Since the second fibrous layer of the wearer's skin becomes less likely to absorb and retain excrement and moisture, it is more difficult to impart a moist feeling to the wearer's skin.

Here, the "hydrophobicity" in this specification refers to a property that does not easily merge with water or retain moisture, and, for example, refers to a contact angle with ion-exchanged water of about 80° to 100°. In addition, the contact angle of ion-exchanged water can be measured by the method described in "measurement of initial contact angle" of Unexamined-Japanese-Patent No. 2005-324010, for example.

The thermoplastic resin fibers contained in the second fiber layer may be the same as those exemplified as the thermoplastic resin fibers contained in the first fiber layer. From the viewpoint of the ease with which fibers between the fiber layers are entangled with each other, Use the same fiber as the thermoplastic resin fiber contained in the first fiber layer (that is, it is composed of the same material (resin) as the thermoplastic resin fiber contained in the first fiber layer, and has the same fiber length and structure. fiber, etc.) is preferred.

In addition, the fineness of the thermoplastic resin fibers 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 the strength, flexibility, skin feel, and liquid permeability of the nonwoven fabric. , preferably in the range of 1.1dtex~4.6dtex. Furthermore, the fineness of the thermoplastic resin fibers contained in the second fiber layer is preferably larger than the respective finenesses of the thermoplastic resin fibers and cotton contained in the first fiber layer. In this way, if the fineness of the thermoplastic resin fibers contained in the second fiber layer is larger than the respective finenesses of the thermoplastic resin fibers and cotton contained in the first fiber layer, the heat contained in the relatively small first fiber layer will be The plastic resin fibers and the cotton are easily entangled with the thermoplastic resin fibers contained in the first fiber layer or in the second fiber layer. Therefore, with the dissociation of the cotton and the thermoplastic resin fibers, the first fiber layer is split or Interlayer peeling between the respective fiber layers is unlikely to occur, and even if the nonwoven fabric contains cotton as a constituent, excellent strength and shape retention can be exhibited. Furthermore, the inter-fiber distance of the thermoplastic resin fibers contained in the second fiber layer tends to be relatively smaller than the inter-fiber distance between the thermoplastic resin fibers and cotton contained in the first fiber layer. The contained fibers (especially cotton) are less likely to fall off to the second surface side through the second fiber layer (that is, the cotton is less likely to fall off to the outside), and re-moisture is also less likely to occur.

The fiber fineness can be calculated from the cross-sectional area and the specific gravity of the fiber (ie, the specific gravity of the fiber's constituents) by measuring the cross-sectional area of the fiber by magnifying and observing the cross-sectional shape of the target fiber using a scanning electron microscope.

Furthermore, in the present invention, the second fiber layer may contain fibers other than the thermoplastic resin fibers described above, optional additives, and the like within a range that does not inhibit the effects of the present invention.

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 effect of the present invention is not hindered, but from the viewpoint of the strength, flexibility, and absorbency of the non-woven fabric, for example, each is 1 g/m. In the range of 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 entire nonwoven fabric is not particularly limited as long as the effect of the present invention is not inhibited, but is usually in the range of 10 g/m ² to 100 g/m ² , preferably 15 g/m ² to 75 g/m ² . range, more preferably in the range of 20g/m ² ~50g/m ² . Further, the thickness of the non-woven fabric is not particularly limited as long as it does not hinder the effect of the present invention, and 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 in the range of 0.8 mm to 2 mm Inside.

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 top sheet, and may be, for example, an intermediate sheet or the like arranged between the top sheet and the absorber. Furthermore, the absorbent article to which the nonwoven fabric of the present invention is applied is not limited to the above-mentioned disposable diapers, and the nonwoven fabric of the present invention can be applied to various absorbent articles such as (light) incontinence pads, sanitary napkins, and panty liners. Moreover, in this invention, the form of a nonwoven fabric is not specifically limited, For example, the form of the nonwoven fabric roll in which the said nonwoven fabric was wound into a roll shape may be sufficient.

[non-woven 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 a nonwoven fabric roll 200 in which the nonwoven fabric 20 is wound into a roll shape. As shown in FIG. 8 , in yet another embodiment of the present invention, the nonwoven fabric roll 200 is formed by winding the nonwoven fabric 20 of the above-described embodiment into a roll shape. Since the non-woven fabric roll 200 uses a non-woven fabric 20 that does not easily fall off the inner cotton even if a physical load such as friction or vibration is applied, the non-woven fabric 20 can be provided to suppress the falling off of the cotton and adapt to the above-mentioned disposable A material for high-speed production of absorbent articles such as disposable diapers (ie, production under conditions where physical loads such as friction and vibration are easily applied).

Moreover, in this invention, it is preferable that the 1st surface of a nonwoven fabric roll is the surface which contacts a mesh support body at the time of manufacture, ie, a mesh surface. In this way, if the first surface of the non-woven fabric is a mesh surface with relatively high fiber density, the non-woven fabric is fed out from the non-woven fabric roll when the non-woven fabric is wound into a roll during the production process of the non-woven fabric or during the production process of the absorbent article. Even if the non-woven fabrics overlapped in the thickness direction rub against each other, the surface structure of the first surface (mesh surface) with high fiber density is not easily changed, and the cotton contained in the first fiber layer can be prevented from falling off from the first surface side.

In addition, the nonwoven fabric or the nonwoven fabric roll of the present invention is not limited to the above-described embodiments and the like, and may be appropriately combined, replaced, or modified within a range that does not depart from the purpose and gist of the present invention. In addition, in this specification, ordinal numbers such as "1st" and "2nd" are used to distinguish the items to which the ordinal numbers are attached, and do not refer to the order, priority, or importance of each item.

1: Disposable diapers (absorbent articles)

2: Surface sheet (liquid permeable sheet)

2a: Side 1

2b: Side 2

20, 20': non-woven

21: The first fiber layer

22: 2nd fiber layer

23: convex part

231: top

23A: convex area

24: Recess

241: Bottom

242: side wall

24A: Recessed area

241A: Bottom area

242A: Sidewall area

200: Non-woven roll

3: Back sheet (liquid impermeable sheet)

4: Absorber

5: side flakes

6: Telescopic member

7: link belt

II, II': marked lines in Figure 1

C: cotton

CB: fiber block

CB _d : exposed part

C _d : cotton fiber

D ₁ : 1st direction

D ₂ : 2nd direction

F ₁ , F ₂ : thermoplastic resin fibers

P _B : Imaginary reference level

L: Long side direction

T: thickness direction

W: width direction

1 : is a top view of the disposable diaper 1 which uses the nonwoven fabric 20 as the surface sheet 2 in one Embodiment of this invention. Fig. 2 is a partial cross-sectional view of the disposable diaper 1 taken along the line II-II' in Fig. 1 . FIG. 3 is a partial perspective view of the nonwoven fabric 20 in one 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. 3 . FIG. 5 is a schematic diagram showing a model of the configuration of the constituent fibers of the nonwoven fabric 20 in the cross-sectional view of FIG. 4 . FIG. 6 is an enlarged view of the portion surrounded by line VI of FIG. 5 . Fig. 7 is a view corresponding to Fig. 5 of a nonwoven fabric 20' in another embodiment of the present invention. FIG. 8 is a perspective view of a nonwoven fabric roll 200 in which the nonwoven fabric 20 is wound into a roll shape.

1‧‧‧Disposable diapers (absorbent articles)

2‧‧‧Surface sheet (liquid permeable sheet)

4‧‧‧Absorber

5‧‧‧Side sheet

6‧‧‧Telescopic elements

7‧‧‧Connecting belt

II, II'‧‧‧Line of Figure 1

L‧‧‧long side direction

W‧‧‧Width direction

Claims (11)

A non-woven fabric for a liquid-permeable sheet of an absorbent article, which has a first surface and a second surface opposite to each other in the thickness direction: The nonwoven fabric is composed of a first fiber layer and a second fiber layer, and the first fiber layer forms the first surface that is the non-skin-facing surface of the liquid-permeable sheet, and contains cotton and thermoplastic resin fibers. 2. The fiber layer system forms the second surface, which is the skin-facing surface of the liquid-permeable sheet, contains thermoplastic resin fibers and does not contain cotton; and the nonwoven fabric includes a plurality of convex portions and a plurality of concave portions, and the plurality of convex portions protruding from the first surface toward the second surface, and the plurality of concave portions are recessed from the second surface toward the first surface, Further, the nonwoven fabric has a convex region extending from the second surface of the convex portion to the first surface in the thickness direction, and a concave region extending from the second surface of the concave portion. Extending to the first surface in the thickness direction, the concave portion region is such that the cotton content of the first fiber layer is smaller than that of the convex portion region. The nonwoven fabric according to claim 1, wherein the concave portion has a bottom portion and a side wall portion extending from the bottom portion toward the convex portion, and the concave portion region extends from the second surface of the side wall portion to the first surface and exists in the above-mentioned The side wall region in the thickness direction contains the aforementioned cotton fiber mass. The nonwoven fabric according to claim 2, wherein the convex portion is a mu portion extending in the first direction, the concave portion is a groove portion, and in a second direction orthogonal to the first direction, the groove portion is adjacent to the mu portion and in the The said 1st direction is extended, and the fiber lump of the said cotton exists in the said 1st fiber layer from the said convex part area|region across the said recessed part area|region. The nonwoven fabric according to claim 3, wherein the fiber mass of the cotton existing across the convex portion region to the concave portion region has a length in the second direction of the portion existing in the convex portion region greater than the length in the second direction of the portion existing in the concave portion region. The length in the second direction of the part is longer. The nonwoven fabric according to any one of claims 2 to 4, wherein in the first fiber layer, the fiber lumps of the cotton are biased toward the first surface side in the thickness direction. The nonwoven fabric according to claim 2, wherein a portion of the cotton fiber mass is exposed from the first surface. The nonwoven fabric according to claim 6, wherein the cross-sectional shape of a part of the cotton-based fibers is a flat shape. The nonwoven fabric according to claim 2, wherein the cotton fiber block has a block portion in which the cotton fibers are aggregated, and a plurality of cotton fibers extending from the block portion toward the first surface side while expanding in the surface direction The formed diffuser fiber portion. The nonwoven fabric according to claim 1, wherein the thermoplastic resin fibers contained in the second fiber layer have a larger fineness than the thermoplastic resin fibers and the cotton contained in the first fiber layer. A non-woven fabric roll for a liquid-permeable sheet of an absorbent article is obtained by winding the non-woven fabric of any one of claims 1 to 9 into a roll shape. The non-woven fabric roll of claim 10, wherein the first surface of the non-woven fabric is a mesh surface.

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