TWI814914B - absorbent articles - Google Patents

Abstract

The present invention provides an absorbent article containing a surface sheet that is less likely to cause uncomfortable irritation to the wearer's skin and has an excellent touch to the skin. In the absorbent article of the present invention, the surface sheet (2) is provided with: a first fiber layer (2a) containing water-retentive fibers (F ₁ ) and forming the skin-side surface of the surface sheet (2); and a second fiber Layer (2b), which contains thermoplastic resin fiber (F ₂ ) and water-retentive fiber (F ₁ ), is adjacent to the non-skin side of the first fiber layer (2a), and forms the non-skin side of the surface sheet (2) On the surface, the proportion of water-retentive fibers (F ₁ ) in the fibers constituting the first fiber layer (2a) is greater than the proportion of water-retentive fibers (F ₁ ) in the fibers constituting the second fiber layer (2b), At least _a part of the water-retentive fibers (F ₁ ) contained in the first fiber layer (2a) is formed in at least a part of the interlaced portions (P _E ) of the fibers by the thermoplastic resin. The melt (F _2M ) of the fiber (F ₂ ) is covered.

Description

absorbent articles

The present invention relates to absorbent articles such as sanitary napkins for physiological use.

As surface sheets used for absorbent articles such as sanitary napkins, sheets containing water-retentive fibers such as cotton fibers that absorb and retain moisture are known. For example, Patent Document 1 discloses a sheet made of natural oils and fats attached thereto. A nonwoven fabric made of bleached cotton fiber (cotton fiber) and thermoplastic short fibers formed by an olefin copolymer at least on the surface of the fiber, and the constituent fibers are three-dimensionally entangled with each other. It is a nonwoven fabric that can be used as a surface material for absorbent articles. . The nonwoven fabric disclosed in Patent Document 1 can be suitably used even in fields where nonwoven fabrics made of conventional absorbent cotton fibers such as surface materials for absorbent articles are not used. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2005-139594

[Problem to be solved by the invention]

However, if the nonwoven fabric disclosed in Patent Document 1 only entangles cotton fibers (water-retaining fibers) and thermoplastic short fibers (thermoplastic resin fibers), it will directly contact the skin of the wearer's crotch area and its surrounding areas. When used as a surface sheet of an absorbent article (that is, the part of the skin that is prone to irritation), the thermoplastic resin fibers contained in the nonwoven fabric tend to give a hard or prickly touch to the wearer's skin. Uncomfortable irritation, etc., and when the absorbent article is used, the fibers may loosen from each other due to friction with the wearer's skin, or the water-retaining fibers may break, leaving the surface sheet on the skin side. The water-retaining fiber will have fluff on its surface, which may cause uncomfortable irritation to the wearer's skin.

Here, an object of the present invention is to provide an absorbent article containing a surface sheet that is less likely to cause uncomfortable irritation to the wearer's skin and has an excellent touch to the skin. [Means used to solve problems]

One aspect (Aspect 1) of the present invention is an absorbent article including a surface sheet, which is characterized by: The aforementioned surface flakes have: a first fiber layer, which contains water-retaining fibers and forms the skin-side surface of the aforementioned surface sheet; and a second fiber layer that includes thermoplastic resin fibers and water-retaining fibers and is adjacent to the non-skin side of the first fiber layer to form the skin-side surface of the surface sheet, The proportion of the water-retentive fibers among the fibers constituting the first fiber layer is greater than the proportion of the water-retentive fibers among the fibers constituting the second fiber layer, At least a part of the water-retentive fibers included in the first fiber layer is coated with a melt of the thermoplastic resin fiber in at least a part of the intersection parts of the fibers.

In the absorbent article of this aspect, in addition to the fact that the first fiber layer in the surface sheet has a greater proportion of water-retentive fibers than the second fiber layer, the thermoplastic resin fiber contained in the second fiber layer At least part of the intersections of the intersections of the fibers included in the first fiber layer becomes a melt covering the water-retentive fibers. Therefore, even if the surface sheet contains thermoplastic resin fibers, the thermoplastic resin fibers It is also less likely to come into contact with the wearer's skin, and it is less likely to give the wearer any uncomfortable irritation such as a hard touch or a prickly touch. Furthermore, in the absorbent article of this aspect, at least a part of the water-retentive fibers contained in the first fiber layer is coated with a melt of the thermoplastic resin fiber in at least part of the intersection parts of the fibers. This is because The intertwining of the fibers in the surface sheet is difficult to loosen, and the water-retaining fibers are not easy to break. Therefore, the water-retaining fibers are less likely to be fluffed due to the loosening of the intertwining and breakage of the water-retaining fibers, and it is less likely to provide the user with the comfort. Uncomfortable irritation caused by fluff. Therefore, the absorbent article of this aspect can realize an absorbent article that is less likely to cause uncomfortable irritation to the wearer's skin and contains a surface sheet that feels good against the skin.

Furthermore, according to another aspect (aspect 2) of the present invention, in the absorbent article according to aspect 1, the thermoplastic resin fiber is one thermoplastic resin fiber entangled with a plurality of the water-retentive fibers. Each of the intersecting portions of the one thermoplastic resin fiber and the plurality of water-retentive fibers is covered with a melt of the one thermoplastic resin fiber.

In the absorbent article of this aspect, each of the intersecting portions of one thermoplastic resin fiber and a plurality of water-retentive fibers is coated with a melt of one thermoplastic resin fiber. Since a plurality of water-retentive fibers are connected together, fluffing caused by the above-mentioned loosening of entanglements and breakage of the water-retentive fibers can be less likely to occur.

In yet another aspect (aspect 3) of the present invention, in the absorbent article according to aspect 1 or 2, the melt of the thermoplastic resin fiber is not exposed on the skin-side surface of the first fiber layer.

In the absorbent article of this aspect, since the molten material of the thermoplastic resin fiber is not exposed on the skin-side surface of the first fiber layer, the presence of the molten material is less likely to be felt by the wearer, and the surface sheet can be obtained more reliably. Good skin feel.

In yet another aspect (Aspect 4) of the present invention, in the absorbent article of any one of the above-described aspects 1 to 3, at least the average fiber length ratio of the water-retaining fibers contained in the first fiber layer is The average fiber length of the aforementioned thermoplastic resin fibers is shorter.

In the absorbent article of this aspect, the average fiber length of the water-retentive fibers contained in the first fiber layer is shorter than the average fiber length of the thermoplastic resin fibers contained in the second fiber layer. Therefore, the water-retentive fibers contained in the second fiber layer are in contact with Since the number of water-retentive fibers in the first fiber layer of one thermoplastic resin fiber is increased, the amount of molten material adhered to each thermoplastic resin fiber of the water-retentive fiber can be increased, making the above-mentioned occurrence less likely to occur. The fluffing of water-retentive fibers.

In yet another aspect (aspect 5) of the present invention, in the absorbent article according to any one of the above aspects 1 to 4, at least the average fiber length of the water-retaining fibers contained in the first fiber layer is Above 5mm and below 35mm.

In the absorbent article of this aspect, since the average fiber length of the water-retaining fibers contained in the first fiber layer is within the above-mentioned specific range, the above-mentioned fluffing of the water-retaining fibers is less likely to occur and the softness of the water-retaining fibers is easily maintained. Sex and touch, the result is that the skin touch of the surface sheet can be made better.

In yet another aspect (Aspect 6) of the present invention, in the absorbent article of any one of the above-described aspects 1 to 5, the thermoplastic resin fiber is a composite fiber, and the composite fiber is a resin with a low melting point. The components are exposed on the surface of the composite fiber.

In the absorbent article of this aspect, since the thermoplastic resin fiber is a composite fiber, in addition to the resin component with a low melting point exposed on the surface of the fiber (for example, in the case of a core-sheath type composite fiber, it is the resin component constituting the sheath part). In the case of composite fibers, it is the resin component on one side) that melts and covers the water-retaining fiber, and a resin component that can maintain a high melting point (for example, in the case of core-sheath type composite fibers, it is the resin component constituting the core, and in the case of parallel-type composite fibers, it is the resin component that forms the core. The resin component on the other side is in a state of intertwining with the water-retaining fibers and other composite fibers, thereby maintaining the predetermined bulkiness of the surface sheet. Thereby, the absorbent article of this aspect is less likely to have the above-mentioned fluffing of the water-retaining fiber, and the surface sheet can easily ensure good softness, touch, cushioning properties, etc.

In yet another aspect (Aspect 7) of the present invention, in the absorbent article of any one of the above-described aspects 1 to 6, the surface sheet has a pressed portion that is depressed from the surface on the skin side toward the thickness direction.

In the absorbent article of this aspect, since the surface sheet has a pressed portion formed by embossing or the like, the pressed portion retains the water-retentive fibers, making it less likely that the above-mentioned fluffing of the water-retentive fibers will occur.

In yet another aspect (Aspect 8) of the present invention, in the absorbent article of any one of the above-described aspects 1 to 7, the surface sheet has: extending along the longitudinal direction of the absorbent article, and A plurality of convex portions are spaced apart in the width direction of the absorbent article, and a plurality of recessed portions extend along the longitudinal direction of the absorbent article and are located between the convex portions adjacent to each other.

In the absorbent article of this aspect, since the surface sheet has the above-mentioned specific concave and convex structure, the contact area between the skin-side surface of the surface sheet and the wearer's skin is reduced, so that the wearer's skin-induced damage can be further reduced. There is a possibility of uncomfortable irritation due to fluffing of the thermoplastic resin fibers and water-retentive fibers contained in the surface sheet.

In yet another aspect (aspect 9) of the present invention, in the absorbent article according to aspect 8, the absorbent article further includes an auxiliary sheet located on the non-skin side of the surface sheet, and the surface sheet is in the plurality of Each of the recessed portions is joined to the aforementioned auxiliary sheet.

In the absorbent article of this aspect, since the surface sheet is joined to the auxiliary sheet at each of the plurality of recessed portions, the water-retentive fibers are retained at the joint portion with the auxiliary sheet, and the above-mentioned fluffing of the water-retentive fibers is less likely to occur.

In yet another aspect (Aspect 10) of the present invention, in the absorbent article of any one of the above-described aspects 1 to 9, the water-retentive fiber is organic cotton.

In this type of absorbent article, since the water-retaining fiber is organic cotton with excellent softness and touch, the surface sheet can easily ensure good softness, touch, etc., and achieve a better skin touch. In addition, if the surface sheet contains such organic cotton, it also has the advantage of creating a sense of security for the user of the absorbent article due to the use of natural materials in the surface sheet.

In yet another aspect (Aspect 11) of the present invention, in the absorbent article of any one of the above-described aspects 1 to 10, the fiber density of the second fiber layer is higher than the fiber density of the first fiber layer. big.

In the absorbent article of this aspect, the fiber density of the second fiber layer becomes greater than the fiber density of the first fiber layer, and the fibers constituting the second fiber layer are close to each other, and the capillary phenomenon is stronger in the second fiber layer. Therefore, the liquid excretion excreted on the skin side surface of the surface sheet (that is, the skin side surface of the first fiber layer) can be quickly attracted to the second fiber layer, and further, the liquid excretion excreted on the skin side of the surface sheet can be quickly attracted to the second fiber layer. The liquid excrement attracted to the second fiber layer quickly moves to the non-skin side of the second fiber layer through the thermoplastic resin fiber. In this way, the absorbent article of this type can not only make the surface sheet excellent in touch against the skin, but also ensure good absorption performance.

In yet another aspect (Aspect 12) of the present invention, in the absorbent article of any one of the above-described aspects 1 to 11, the average distance between the fibers of the second fiber layer is longer than that of the first fiber layer. The average distance between the aforementioned fibers is shorter.

In the absorbent article of this aspect, since the average distance between the fibers of the second fiber layer is shorter than the average distance between the fibers of the first fiber layer, the fibers constituting the second fiber layer are close to each other, and the second fiber layer can allow The capillary phenomenon occurs more strongly, so the liquid excretion excreted on the skin side surface of the first fiber layer can be quickly attracted to the second fiber layer, and further, the liquid attracted to the second fiber layer can be The excrement in the form quickly moves to the non-skin side of the second fiber layer through the thermoplastic resin fiber. In this way, the absorbent article of this type can not only make the surface sheet excellent in touch against the skin, but also ensure good absorption performance.

In yet another aspect (Aspect 13) of the present invention, in the absorbent article according to any one of the above aspects 1 to 12, the absorbent article further includes the surface sheet located at both ends in the width direction. The pair of side sheets on the skin side have a dynamic friction coefficient when wet that is lower than the dynamic friction coefficient of the surface sheet when wet.

The absorbent article of this aspect can further provide smoothness as an absorbent article because the pair of side sheets that are easily in contact with the wearer's leg skin have a lower dynamic friction coefficient than the surface sheet that has a better skin feel. skin touch. [Effects of the invention]

According to the present invention, it is possible to provide an absorbent article containing a surface sheet that is less likely to cause uncomfortable irritation to the wearer's skin and has an excellent touch to the skin.

[Form for carrying out the invention]

Hereinafter, suitable embodiments of the absorbent article of the present invention will be described in detail with reference to the drawings. In addition, in this specification, unless there are any special requirements, only "an object (for example, sanitary napkins (absorbent articles) for sanitary napkins (absorbent articles)) placed on a horizontal surface in an unfolded state is viewed from the upper side in the vertical direction toward the thickness direction of the object. ), etc.)" is called "looking down".

FIG. 1 is a plan view of the sanitary napkin 1 according to an embodiment of the present invention in an unfolded state, viewed from the surface sheet 2 side in the thickness direction T. FIG. 2 is a plan view along line II of the sanitary napkin 1 in FIG. 1 - Sectional view of line II. The sanitary napkin 1 of this embodiment has a longitudinal direction L, a width direction W, and a thickness direction T that are orthogonal to each other, as shown in FIGS. 1 and 2 , and further has a center passing through the width direction W. A longitudinal center line CL (imaginary line) extending in the longitudinal direction _L , and a transverse center line CW (imaginary line) passing through the center of the longitudinal direction L and extending in the transverse direction _W.

In addition, in this specification, in the longitudinal direction L of the sanitary napkin 1, the proximal side opposite to the widthwise center line C _W is called the inner side in the longitudinal direction L, and the proximal side opposite to the widthwise center line C is called the inner side in the longitudinal direction L. The far side opposite to C _W is called the outer side in the long side direction L. Similarly, in the width direction W of the sanitary napkin 1, the near side opposite to the longitudinal center line _CL is called the inner side in the width direction W, and the far side opposite to the longitudinal center line _CL is called the inner side in the width direction W. The bit side is called the outer side in the width direction W. In addition, in this specification, any direction in a plane including the longitudinal direction L and the width direction W is called a "planar direction". In addition, in this specification, in the thickness direction T of the sanitary napkin 1, the proximal side facing the skin surface of the user when wearing the sanitary napkin 1 is called the skin side, and the sanitary napkin 1 is called the skin side. When wearing 1, the far side opposite to the wearer's skin is called the non-skin side. In addition, the definitions of these terms are also applied to various members constituting the sanitary napkin 1 and absorbent articles other than the sanitary napkin 1 .

[Menstrual sanitary napkin] As shown in FIG. 1 , a sanitary napkin 1 according to an embodiment of the present invention (an example of an “absorbent article” in the present invention) has a substantially rectangular shape long in the longitudinal direction L and short in the width direction W when viewed from above. It has a vertically elongated shape in which both end edges in the longitudinal direction L project in arcs toward the outer side in the longitudinal direction L. Furthermore, the sanitary napkin 1 has a central portion in the longitudinal direction L, and both end portions in the width direction W of the sanitary napkin 1 project toward the outer side in the width direction W in a substantially trapezoidal shape. A pair of wings 9,9.

In addition, the shape of the sanitary napkin 1 when viewed from above 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, any longitudinal shape can be adopted that corresponds to various usage aspects. shape (for example, rectangle, oval, hourglass, etc.). Furthermore, the shape of the wing portion 9 is not limited to the above-mentioned substantially trapezoidal shape, and may be, for example, a semicircular shape, a semielliptic shape, or the like.

The sanitary napkin 1 of this embodiment has a surface sheet 2 forming the skin side surface of the sanitary napkin 1 in the thickness direction T and a non-skin side surface of the sanitary napkin 1 as shown in FIG. 2 The basic structure is the back sheet 3 on the surface and the absorber 4 arranged between the two sheets. Moreover, in this embodiment, as shown in FIGS. 1 and 2 , the sanitary napkin 1 further includes an auxiliary sheet 5 disposed between the surface sheet 2 and the absorbent body 4 in the thickness direction T, and a sanitary napkin 1 disposed on the sanitary napkin 1 . A pair of side sheets 6, 6 are provided at both ends in the width direction W of the sanitary napkin 1. In addition, in this embodiment, each of the pair of side sheets 6 and 6 is a pair of loop portions 5L formed by folding both ends of the auxiliary sheet 5 in the width direction W toward the non-skin side. , the non-skin-side surface of 5L is joined so that the skin-side surface of the inner end of each side sheet 6 in the width direction W overlaps, and the outer side of each side sheet 6 in the width direction W The non-skin side surface of the back sheet 3 is bonded to the skin side surface of the back sheet 3 .

Hereinafter, various components constituting the sanitary napkin 1 of this embodiment will be described in further detail. Here, FIG. 3 is an enlarged schematic diagram of an important part of the first fiber layer 2a in the surface sheet 2, FIG. 4(a) is an enlarged plan view of the surface sheet 2, and FIG. 4(b) is a diagram along the line of FIG. 4(a). Cross-sectional view of the surface sheet 2 along line IVb-IVb.

[Surface Sheet] The surface sheet 2 has a shape extending in the longitudinal direction L from the longitudinal end on the front side of the sanitary napkin 1 across the longitudinal end on the rear side when viewed from above, as shown in FIG. 1 . Rectangular shape when viewed from above. The surface sheet 2 is composed of a liquid-permeable sheet-like member, and is formed at a position on the skin side in the thickness direction T of the sanitary napkin 1 as shown in FIG. 2 so as to be in contact with the wearer's skin. The contact surface (that is, the surface of the sanitary napkin 1 on the skin side). In addition, in this specification, in the longitudinal direction L of the sanitary napkin 1 , the side that is opposite to the wearer's abdomen when the sanitary napkin 1 is worn is called the front side, and the front side is called the front side. The other side that is the opposite distal side to the wearer's abdomen is called the rear side. In this regard, as shown in FIG. 1 , the sanitary napkin 1 has a front side area _AF , a center area A _C , and a rear side area A _B in the longitudinal direction L.

Furthermore, in this embodiment, the surface sheet 2 is composed of a first fiber layer 2a that contains water-retentive fiber F ₁ and forms the skin-side surface of the surface sheet 2 , and a thermoplastic resin-containing fiber F ₂ and a water-retaining fiber F. ₁ , and is composed of a two-layered sheet-like member of the second fiber layer 2b adjacent to the non-skin side surface of the first fiber layer 2a and the non-skin side surface of the sheet 2. In addition, the surface sheet 2 may further include one or a plurality of fiber layers on the non-skin side of the second fiber layer 2b, and may have a multi-layer structure of three or more layers as a whole.

(First fiber layer) As described above, the first fiber layer 2a contains water-retentive fiber F ₁ . The water-retentive fiber _F1 is not particularly limited as long as it has the property of absorbing and retaining water (water-retaining property), and examples thereof include cellulose-based fibers. Furthermore, the cellulose-based fiber is not particularly limited as long as it contains cellulose. Examples thereof include natural cellulose fiber, regenerated cellulose fiber, purified cellulose fiber, and semi-synthetic cellulose fiber. Examples of natural cellulose fibers include plant fibers, such as seed wool fibers such as cotton, bast fibers such as linen, vein fibers such as hemp, and fruit fibers such as coconut.

Examples of cotton (fiber) include American cotton such as upland cotton, sea island cotton, Asian cotton, and Arabian cotton. In addition, as cotton (fiber), organic cotton, quasi-organic cotton (trademark), etc. can also be used. However, organic cotton refers to cotton certified by GOTS (Global Organic Textile Standard). As for the regenerated cellulose fiber, rayon can be mentioned. For example, viscose rayon obtained from viscose fiber, multi-component rayon, modal fiber, and copper ammonium rayon obtained from the copper ammonium salt solution of cellulose. (also known as "cupro fiber") and other fibers. As for the refined cellulose fiber, Lyocell fiber can be used. Specifically, the spinning stock solution (spinning stock solution) can be made by dissolving the pulp in an aqueous solution of N-methylmorphine-N-oxide. , extruded into a thin solution of N-methylmorphine-N-oxide to make fibers, etc. In addition, purified cellulose is sold, for example, as Tencel Cotton (trademark). Examples of semi-synthetic cellulose fibers include acetate fibers such as tripolyacetate and dimer acetate.

Among the various water-retaining fibers mentioned above, from the viewpoint of water retention and skin feel, the water-retaining fiber _F1 is preferably natural cellulose fiber, cotton is more ideal, and organic cotton is even more ideal. If the water-retentive fiber F ₁ is organic cotton with excellent softness, touch, etc., the surface sheet 2 can easily ensure good softness, touch, etc., and achieve better skin touch. In addition, if the surface sheet 2 contains such organic cotton, the wearer of the sanitary napkin 1 also has the advantage of being able to create a sense of security due to the use of natural materials in the surface sheet 2 .

(Second fiber layer) As described above, the second fiber layer 2 contains the thermoplastic resin fiber F ₂ and the water-retaining fiber F ₁ . The thermoplastic resin fiber F ₂ is not particularly limited as long as it is a fiber formed of a thermoplastic resin (generally hydrophobic fiber). Examples of the thermoplastic resin forming the thermoplastic resin fiber F ₂ include olefin-based resins such as polyethylene (PE), polypropylene (PP), and ethylene-vinyl acetate copolymer (EVA). Well-known resins such as polyester-based resins such as polyethylene terephthalate (PET) and polylactic acid (PLA), and polyamide-based resins such as 6-nylon, can also be used alone. , two or more types of resins can also be used together.

In addition, the structure of the thermoplastic resin fiber F ₂ is not particularly limited, and examples include core-sheath type composite fibers such as PET (core)/PE (sheath), PP (core)/PE (sheath), etc. , parallel type composite fiber, island/sea type composite fiber, etc.; hollow fiber; flat, Y-shaped, C-shaped, etc. special-shaped cross-section fiber; latent crimp or explicit crimp three-dimensional crimp fiber; borrowed Fibers having such structures, such as split fibers split by physical loads such as water flow, heat, and embossing processing, may be used alone, or two or more types of fibers may be used in combination. In addition, in the sanitary napkin 1 of this embodiment, the thermoplastic resin fiber F ₂ of the second fiber layer 2 b is a core-sheath type composite fiber of PP (core)/PE (sheath).

In addition, the water-retentive fiber F ₁ contained in the second fiber layer 2b is the same as the water-retentive fiber F ₁ of the first fiber layer 2a.

Furthermore, in the first fiber layer 2a and the second fiber layer 2b constituting the surface sheet 2, the ratio of the water-retaining fiber _F1 in the fiber constituting the first fiber layer 2a is greater than the water-retaining fiber F1 in the fiber constituting the second fiber layer 2b. The proportion of sex fiber F ₁ is more. Therefore, even if the surface sheet 2 contains the thermoplastic resin fiber F ₂ , the thermoplastic resin fiber F ₂ is less likely to come into contact with the wearer's skin and is less likely to give the wearer a hard or prickly touch. The uncomfortable stimulation of waiting.

In addition, the proportion of the water-retentive fiber F ₁ among the fibers constituting the first fiber layer 2 a is higher than that of all the fibers constituting the first fiber layer 2 a (except for the thermoplastic resin fiber F ₂ described below) from the viewpoint of improving the skin feel of the surface sheet 2 The total mass of the melt.) is ideally 70 mass% to 100 mass%, more preferably 80 mass% to 100 mass%, and still more preferably 90 mass% to 100 mass%. When the proportion of the water-retaining fiber F ₁ is set to 70% by mass or more, the wearer can easily recognize that the skin-side surface of the surface sheet 2 formed by the first fiber layer 2 a contains the water-retaining fiber F ₁ and can easily feel it in reality. The superiority of the feeling to the touch.

In addition, among the fibers constituting the first fiber layer 2a, fibers other than the water-retaining fiber _F1 are not particularly limited as long as they can form a layer with liquid permeability. For example, the fibers included in the second fiber layer 2b are also included. Thermoplastic resin fiber F ₂ The same thermoplastic resin fiber. In this embodiment, the first fiber layer 2a has a proportion of the water-retentive fiber F ₁ of 100% by mass, that is, it does not contain fibers other than the water-retentive fiber F ₁ .

Furthermore, in this embodiment, the average fiber length of the water-retentive fibers F ₁ of the second fiber layer 2b is shorter than the average fiber length of the water-retentive fibers F ₁ of the first fiber layer 2a. Thereby, since at least the fibers constituting the second fiber layer 2b are easily close to each other (that is, the distance between the fibers is shortened), the capillary phenomenon is more likely to occur. Therefore, liquid excretions such as menstrual blood and urine can be used. It is strongly attracted to the second fiber layer 2b.

As shown in FIG. 3 , at least a part of _the water-retaining fibers F ₁ contained in the first fiber layer 2 a is at least a part of the intertwined parts _PE between the fibers, and is formed by the thermoplastic resin fiber F ₂ The melt F _2M is coated. In this way, in the sanitary napkin 1 of this embodiment, in addition to the fact that the proportion of the water-retentive fiber F ₁ in the first fiber layer 2 a in the surface sheet 2 is greater than the proportion of the water-retentive fiber F ₁ in the second fiber layer 2 b, Because at least a part of the thermoplastic resin fiber F ₂ contained in the second fiber layer 2 b forms a covered water-retentive fiber _F in at least a part of the intertwined part _PE of the fibers contained in the first fiber layer 2 a The melt F _2M of ₁ , therefore, even if the surface sheet 2 contains the thermoplastic resin fiber F ₂ , the thermoplastic resin fiber F ₂ is not easy to contact the wearer's skin, and it is not easy to give the wearer a hard touch. Uncomfortable stimulation such as irritation, tingling sensation, etc. Furthermore, in the sanitary napkin 1 of this embodiment, at least a part of the intersections _{PE between fibers is coated with a melt F 2M of} the thermoplastic resin fiber F ₂ contained in the first fiber layer 2 a At least a part of the water-retentive fibers F ₁ , so that the intertwining of the fibers in the surface sheet 2 is difficult to loosen and the water-retentive fibers F ₁ are not easy to break. Therefore, the loosening of the intertwining and the water-retaining fiber are less likely to occur. The fluffing of the water-retentive fiber _F1 caused by the breakage of the fiber _F1 makes it difficult for the wearer to feel uncomfortable stimulation caused by the fluffing. Therefore, the sanitary napkin 1 of this embodiment is less likely to cause uncomfortable stimulation to the wearer's skin and contains the surface sheet 2 that has an excellent skin feel.

In addition, in this specification, the intersection part refers to the part where fibers intersect with each other, and includes an intersection point and a peripheral part of this intersection point. In addition, in this specification, a molten substance refers to a state which has solidified from a molten state.

Furthermore, as described above, in this embodiment, core-sheath type composite fibers are used as the thermoplastic resin fibers F ₂ contained in the second fiber layer 2 b of the surface sheet 2 . Thereby, the surface sheet 2 can maintain the core portion made of a resin with a high melting point and the water-retaining fiber F ₁ in addition to the sheath portion formed of a resin component with a low melting point of the core-sheath type composite fiber melt-coated with the water-retaining fiber F 1 _1. The other core-sheath type composite fibers (thermoplastic resin fibers F ₂ ) are in an intertwined state and can maintain a predetermined bulk as a surface sheet. In addition, even when a thermoplastic resin fiber is used, such as a side-by-side type conjugate fiber in which a resin component with a low melting point is exposed on the surface of the conjugate fiber, the same effect as described above can be achieved.

Furthermore, in this embodiment, the above-mentioned thermoplastic resin fiber F ₂ is one thermoplastic resin fiber F ₂ intertwined with a plurality of water-retentive fibers F ₁ , and the one thermoplastic resin fiber F ₂ Each of the intersecting portions _PE with the plurality of water-retaining fibers F ₁ is covered with the melt F _2M of the one thermoplastic resin fiber F ₂ . In this way, if each of the intersections _PE of one thermoplastic resin fiber F ₂ and a plurality of water-retentive fibers F ₁ is covered with the melt F _2M of one thermoplastic resin fiber F ₂ , because one fiber F 2 passes through Since the thermoplastic resin fiber F ₂ connects a plurality of water-retentive fibers F ₁ , fluff caused by the above-mentioned loosening of entanglements and breakage of the water-retentive fibers F ₁ is less likely to occur.

Furthermore, in the present invention, the molten material of the thermoplastic resin fiber is not exposed on the skin-side surface of the first fiber layer. If the melt of the thermoplastic resin fiber is not exposed on the skin-side surface of the first fiber layer, the presence of the melt will be less likely to be felt by the wearer, and a good skin feel of the surface sheet can be more reliably obtained.

The fiber length (average fiber length) of the water-retentive fibers F ₁ in the first fiber layer 2 a is not particularly limited as long as it does not hinder the effects of the present invention. However, at least the average fiber length of the water-retentive fibers F ₁ contained in the first fiber layer 2 a The fiber length is preferably shorter than the average fiber length of the thermoplastic resin fiber _F2 . If the average fiber length of the water-retentive fiber F ₁ contained in the first fiber layer 2 a is shorter than the average fiber length of the thermoplastic resin fiber F 2 contained in the second fiber layer 2 b , the water-retentive fiber F ₁ contained in the second fiber layer 2 b is in contact with Since the number of water-retentive fibers F ₁ in the first fiber layer 2 a of one thermoplastic resin fiber F ₂ is large, the molten material F _2M of the thermoplastic resin fiber F ₂ can be increased per one of the water-retentive fibers. The amount of adhesion may cause the above-mentioned fluffing of the water-retentive fiber _F1 to easily occur.

In addition, the specific average fiber length of the water-retentive fiber F ₁ contained in the first fiber layer 2a is, for example, an average fiber length of 5 mm to 80 mm (that is, 5 mm or more and 80 mm or less). If the average fiber length of the water-retaining fiber F ₁ is 5 mm or more, it is easy to maintain the softness and feel of the water-retaining fiber F ₁ and the fibers are easily entangled with each other, so it is easy to obtain sufficient strength. On the other hand, if the average fiber length of the water-retaining fiber F ₁ is 80 mm or less, a part of the water-retaining fiber F ₁ is less likely to extend outward in the width direction W of the sanitary napkin 1 , and therefore, it is transmitted to The water-retaining fiber F ₁ extending outward in the width direction W makes it difficult for liquid excretion to leak out from the width direction W of the sanitary napkin 1 . In addition, the average fiber length of the water-retentive fiber F ₁ contained in the first fiber layer 2a is preferably 5 mm or more and 60 mm or less, and is more preferably 5 mm or more and less than 35 mm. If the average fiber length of the water-retaining fiber F ₁ contained in the first fiber layer 2 a is 5 mm or more and less than 35 mm, the above-mentioned fluffing of the water-retaining fiber F ₁ is less likely to occur, and the softness of the water-retaining fiber F ₁ is easily maintained. , touch, as a result, the skin touch of the surface sheet 2 can be made better.

In addition, the fineness, average fiber length, etc. of the fibers other than the water-retaining fiber F ₁ in the first fiber layer 2a are not particularly limited. However, considering the impact on the skin feel of the water-retaining fiber F ₁ , it depends on the water retention. It is ideal that the fiber _F should be the same (in the range of 0.5 times to 2 times). However, in this embodiment, as mentioned above, the first fiber layer 2a does not contain fibers other than the water-retaining fiber _F1 .

The proportion of the water-retentive fiber F ₁ among the fibers constituting the second fiber layer 2b is not particularly limited as long as it is smaller than the proportion of the water-retentive fiber F ₁ constituting the first fiber layer 2a. The proportion of the water-retentive fiber F ₁ in the second fiber layer 2 b is, for example, 50 mass % to 90 mass % based on the total mass of all fibers constituting the second fiber layer 2 b. If the proportion of water-retentive fiber F ₁ is 50 mass % or more, the tactile feeling in the state of applying pressure in the thickness direction T can be made good. If the proportion of water-retentive fiber F ₁ is 90 mass % or less, then The effect of preventing fluffing caused by the melt F _2M of the thermoplastic resin fiber F ₂ is more easily exhibited stably. Furthermore, the proportion of the water-retentive fiber F ₁ in the second fiber layer 2b is ideally 60 mass% to 85 mass%, and more preferably 70 mass% to 80 mass%. Correspondingly, the proportion of the thermoplastic resin fiber _F in the second fiber layer 2b is, for example, 10 mass% to 50 mass%, and 15 mass% to the total mass of all constituent fibers of the second fiber layer 2b. 40% by mass is ideal, and 20% to 30% by mass is more ideal. In addition, the second fiber layer 2b may include a third fiber in addition to the water-retentive fiber _F1 and the thermoplastic resin fiber _F2 .

In addition, the fineness of the water-retentive fiber F ₁ contained in the second fiber layer 2b is preferably the same as that of the water-retentive fiber F ₁ in the first fiber layer 2a.

The fiber length (average fiber length) of the water-retaining fiber F ₁ of the second fiber layer 2b is not particularly limited as long as it does not hinder the effect of the present invention. However, like the above-mentioned first fiber layer 2a, it is longer than that of the thermoplastic resin fiber F ₂ . A shorter average fiber length is ideal. If the average fiber length of the water-retaining fiber F ₁ is shorter than the average fiber length of the thermoplastic resin fiber F ₂ , the number of water-retaining fibers F ₁ contacting one thermoplastic resin fiber F ₂ increases, so it can be increased. The adhesion amount of the melt F _2M of the thermoplastic resin fiber F 2 per one water-retentive fiber makes it less likely to cause _the above-mentioned loosening of the entanglement of the fibers and the breakage of the water-retentive fiber F ₁ .

In addition, the specific average fiber length of the water-retentive fiber F ₁ contained in the second fiber layer 2b is, for example, an average fiber length of 3 mm to 40 mm. If the average fiber length of the water-retaining fiber F ₁ is 3 mm or more, it is easy to maintain the softness and feel of the water-retaining fiber F ₁ and the fibers are easily entangled with each other, so it is easy to obtain sufficient strength. On the other hand, if the average fiber length of the water-retaining fiber F ₁ is 40 mm or less, the water-retaining fiber F ₁ will easily enter the thermoplastic state because the fibers in the fiber web state have a high degree of dynamic freedom during the production of the second fiber layer 2b. Because of the gaps between the resin fibers F ₂ , the distance between the fibers in the second fiber layer 2 b tends to become shorter, and the fiber density of the second fiber layer 2 b tends to increase. In addition, the average fiber length of the water-retentive fiber F ₁ contained in the second fiber layer 2b is not particularly limited, as is the case of the water-retentive fiber F ₁ of the first fiber layer 2a mentioned above, and is 5 mm or more and less than 35 mm. for ideal. If the average fiber length of the water-retaining fiber F ₁ contained in the second fiber layer 2 b is within this range, the softness and feel of the water-retaining fiber F ₁ can be easily maintained, and as a result, the skin feel of the surface sheet 2 can be improved. Better ones.

Furthermore, in the present invention, a mixed water-retentive fiber obtained by mixing two or more types of water-retentive fibers with different average fiber lengths may be used as at least the water-retentive fiber F1 contained in the second fiber layer _2b . For example, the water-retentive fiber may be a mixture of a water-retentive fiber with an average fiber length of 15 mm to 40 mm (ideally 20 mm to 35 mm) and a water-retentive fiber with an average fiber length of 15 mm to 40 mm (ideally 20 mm to 35 mm). Water-retaining fiber with a length of 3mm~25mm (ideally 5mm~20mm). If this type of mixed water-retaining fiber is used as the water-retaining fiber F ₁ of the second fiber layer 2b, the water-retaining fiber with an average fiber length can not only improve the water retention and skin feel of the second fiber layer 2b, but also improve the skin feel. The inter-fiber distance of the second fiber layer 2b is shortened by the water-retentive fibers with short average fiber length.

In addition, when the second fiber layer 2b contains one or more fiber layers on the non-skin side, that is, when the surface sheet 2 has a three-layer or multi-layer structure as a whole, from the perspective of further improving the liquid permeability, the closer to the surface sheet 2 The fiber layer on the surface of the non-skin side of 2 has a relatively low proportion of water-retaining fibers, and the average fiber length of the water-retaining fibers F ₁ is ideal.

That is, the ease with which the thermoplastic resin fiber F ₂ as the second fiber layer 2 b and the water-retentive fiber F ₁ that are the main constituent fibers of the first fiber layer 2 a can be entangled with each other. The thermoplastic resin fiber F 2 of the second fiber layer 2 b is required to facilitate the transfer of liquid excrement from the first fiber layer 2 a and prevent interlayer peeling between the first fiber layer 2 a and the second fiber layer ₂ b. The fineness is preferably smaller than the fineness of the water-retentive fiber F ₁ of the first fiber layer 2a.

In addition, the fiber length (average fiber length) of the thermoplastic resin fiber F ₂ of the second fiber layer 2 b is not particularly limited as long as it does not hinder the effect of the present invention. For example, it can be 10 mm to 80 mm. However, the thermoplastic resin fiber F 2 as the second fiber layer ₂ b and the water-retentive fiber F ₁ as the main constituent fiber of the first fiber layer 2 a are easily entangled with each other, that is, from the first fiber layer 2 a From the perspective of the ease of migration of liquid excrement and preventing interlayer delamination between the first fiber layer 2a and the second fiber layer 2b, the average fiber length of the thermoplastic resin fiber _F2 of the second fiber layer 2b is consistent with the first The average fiber length of the water-retentive fiber F ₁ of the fiber layer 2a and the second fiber layer 2b is preferably relatively long, and for example, the average fiber length is 15 mm to 100 mm.

The thickness of each of the first fiber layer 2a and the second fiber layer 2b is not particularly limited as long as it does not hinder the effect of the present invention. For example, a thickness of 0.05 to 4 mm is used, and a thickness of 0.1 to 3 mm is ideal, and a thickness of 0.2 to 2 mm is used. More ideal. However, when the thickness of the first fiber layer 2a is relatively thick and the thickness of the second fiber layer 2b is relatively thin, the skin touch of the first fiber layer 2a is good and it is easy to suppress the back seepage into the wearer's skin. In addition, When the thickness of the first fiber layer 2a is relatively thin and the thickness of the second fiber layer 2b is relatively thick, it is easy to cover the first fiber layer 2a with the melt F _2M of the thermoplastic resin fiber F ₂ of the second fiber layer 2b. Since the water-retaining fiber F ₁ is used, the fluffing caused by the water-retaining fiber F ₁ can be suppressed more reliably. In addition, the thickness of the surface sheet 2 (that is, the total thickness of each fiber layer) is not particularly limited as long as it does not hinder the effect of the present invention. For example, a thickness of 0.1 to 5 mm is used, and a thickness of 0.4 to 4 mm is ideal, and a thickness of 0.8 to 4 mm is ideal. A thickness of 3mm is more ideal.

Here, the ratio of fiber types in a sheet such as a fiber layer can be measured as follows. That is, the water-retentive fiber and the thermoplastic resin fiber are colored with different colors according to the following procedure, and the ratio of fiber types can be measured. (1) Cut out the surface sheet 2 with a size of 70 mm×70 mm as a sample. (2) By coloring using the fiber identification reagent Q (KayastainQ) (Japanese Color Dyeing Co., Ltd.), only the water-retentive fiber is dyed blue, and only the thermoplastic resin fiber is dyed yellow. (3) Using a digital microscope VHX-100 manufactured by Keynes Co., Ltd., measure the ratio of blue to yellow when viewed from the surface of the skin side of the sample (first fiber layer 2a) in a range of 50 mm × 50 mm, as The ratio of fiber types in the first fiber layer 2a. On the other hand, the ratio of blue to yellow when viewed from the non-skin side surface (second fiber layer 2b) was measured in the range of 50 mm×50 mm as the ratio of fiber types in the second fiber layer 2b. In addition, when judging the size relationship of the ratio of fiber types, if the size relationship of the above-mentioned blue to yellow ratio is obvious in appearance, it can be judged by its appearance. However, the size of the above-mentioned blue to yellow ratio If the relationship cannot be determined based on appearance alone, count the number of fibers colored in various colors, and calculate each fiber from the number and the structural characteristics of each fiber (for example, fiber length, fiber size, specific gravity, etc.) The total quality can be judged by comparing its total quality.

In addition, the distance between fibers in a sheet such as a fiber layer can be measured according to the following measurement method. (1) Cut out the surface sheet 2 with a size of 10 mm×10 mm as a sample. (2) Use the digital microscope VHX-100 (lens VH-Z20R + variable lighting accessory K20) manufactured by Keynes Co., Ltd. of Japan, with a shooting magnification of 200 times and a measurement area of 1300 μm vertical × 1735 μm horizontal to photograph the skin of surface sheet 2 The image of each surface on the skin side (first fiber layer 2a) and the back surface of the non-skin side (second fiber layer 2b). At this time, a total of five images are taken for each depth of 20 μm in the range of 0 μm to 100 μm for each surface on the skin side and the non-skin side. (3) From each obtained image, determine the area of the portion where fibers do not exist. At this time, the presence or absence of fibers in the pixel is determined based on whether the brightness of each pixel in each acquired image is lower or higher than a predetermined brightness (threshold), and the presence or absence of fibers in the shooting area in each image is determined. The presence or absence of fiber. However, since only the portions where fibers do not exist transmit light and become brighter (that is, because the brightness becomes higher), this is used to determine the area of the portions where fibers do not exist in the imaging area. (4) The calculated area of the portion where fibers do not exist is subtracted from the surface of the photographed region (measured area), and then divided by the surface of the photographed region (measured area) to calculate the void ratio. The calculation is carried out for each image with a depth of 20 μm, and five void ratios are calculated. (5) The average value of each of the five calculated void ratios is used as the void ratio of each surface of the skin side surface (first fiber layer 2a) and non-skin side surface (second fiber layer 2b) of the surface sheet 2 . Comparing the size of the void ratio can determine the size of the distance between fibers. In other words, when the void ratio is large, it can be said that the distance between fibers is large. For example, on the skin-side surface of the surface sheet 2 (first fiber layer 2a: surface with 100% cotton fiber (water-retaining fiber), for example), the porosity is 25.4%, and on the non-skin-side surface (second fiber layer 2b : For example, the surface of 60% cotton fiber (water-retaining fiber) and 40% thermoplastic resin fiber has a void rate of 24.5%.

In addition, the fiber length (average fiber length) of the fibers of sheets such as fiber layers can be determined in accordance with "A7.1 Measurement of fiber length" in Annex A of JIS L 1015:2010. Standard method) Measure the length of each fiber on a graduated glass plate. In addition, the above method is equivalent to the test method of ISO 6989 issued in 1981.

In addition, the basis weight of a sheet such as a fiber layer can be measured according to the following measurement method. That is, one fiber layer is produced, and the fiber layer is cut into a size of 5 cm × 5 cm as a sample. After drying in an environment of 100°C or above, the mass of the sample is measured. Next, the basis weight of the sample is calculated by dividing the measured mass by the area of the sample. The basis weight of the 10 samples was averaged as the basis weight of the sheet.

In addition, the thickness of a sheet such as a fiber layer can be measured according to the following measurement method. That is, a digital microscope VHX-100 manufactured by Keynes Co., Ltd. is used to capture an enlarged image from the vertical direction of the cross section of the surface sheet 2 . At this time, the enlarged image is an image enlarged to a magnification that can capture the entire surface sheet 2 in the thickness direction T, and the magnification is, for example, 20 to 50 times. The obtained magnified image (3D image) is converted into a 2D image, and the thickness of each fiber layer is measured in the 2D image. The thickness of the surface sheet 2 was determined as the average value of the thicknesses measured at three separate sections.

Furthermore, in the sanitary napkin 1 of the above-described embodiment, it is preferable that the average distance between the constituent fibers of the second fiber layer 2b is shorter than the average distance between the constituent fibers of the first fiber layer 2a. If the average distance between the constituent fibers of the second fiber layer 2b is shorter than the average distance between the constituent fibers of the first fiber layer 2a, since the fibers constituting the second fiber layer 2b are close to each other, the second fiber layer can allow The capillary phenomenon occurs more strongly, so the liquid excretion excreted on the skin-side surface of the first fiber layer 2a can be quickly attracted to the second fiber layer 2b, and further, the liquid excretion that has been excreted to the second fiber layer 2b can be attracted The liquid excrement of 2b quickly moves to the non-skin side of the second fiber layer _2b by the thermoplastic resin fiber F2. Therefore, the sanitary napkin 1 having such a structure can ensure good absorption performance while making the surface sheet 2 excellent in touch against the skin.

Furthermore, in the sanitary napkin 1 of this embodiment, it is preferable that the fiber density of the second fiber layer 2b is greater than the fiber density of the first fiber layer 2a. That is, it is desirable that a gradient of fiber density exists in the thickness direction T of the surface sheet 2 so that the fiber density becomes higher from the first fiber layer 2a toward the second fiber layer 2b. In this way, if the fiber density of the second fiber layer 2b becomes greater than the fiber density of the first fiber layer 2a, since the fibers constituting the second fiber layer 2b are close to each other, the capillary phenomenon can be further enhanced in the second fiber layer 2b. It is strongly generated, so the liquid excretion supplied to the skin-side surface of the surface sheet 2 (that is, the skin-side surface of the first fiber layer 2a) can be quickly attracted to the second fiber layer 2b. Furthermore, , the liquid excrement attracted to the second fiber layer 2b can be quickly moved to the non-skin side of the second fiber layer _2b through the thermoplastic resin fiber F2. Therefore, the sanitary napkin 1 having such a structure can ensure good absorption performance while making the surface sheet 2 excellent in touch against the skin.

However, when the non-skin side surface of the second fiber layer 2b is further provided with one or more fiber layers, that is, when the surface sheet 2 has a multi-layer structure of three or more layers, the closer to the non-skin side of the surface sheet 2 It is ideal for the fiber layer on the side surface to have a relatively high fiber density. This can further improve the liquid permeability from the fiber layer located on the skin side to the fiber layer located on the non-skin side, allowing liquid excrement to move to the auxiliary sheet 5 and the absorbent body 4 more stably.

In addition, the fiber density of a sheet such as a fiber layer can be measured according to the following measurement method. (1) Cut out the surface sheet 2 with a size of 10 mm×10 mm as a sample. (2) Use a scanning electron microscope (JCM-5100 manufactured by JEOL Ltd.) to magnify and observe the cross-section parallel to the thickness direction T of the sample. The magnification is set to a magnification that can measure the cross sections of 30 to 60 fibers in one screen (for example: 150 times to 500 times). (3) Divide the observation area into three equal parts in the thickness direction T: the skin side layer, the middle layer, and the non-skin side layer. Let the skin side layer be the first fiber layer 2a and the non-skin side layer be the second fiber layer 2a. After 2 fiber layers 2b, the number of fiber sections in each fiber layer is measured. That is, the number of cross sections of fibers cut in a predetermined area is counted. (4) The number of fiber cross-sections obtained was converted into the number of fiber cross-sections per 1 mm ² , and this was taken as the fiber density (fibers/mm ² ). The measurement was performed at 3 locations, and the average value of the side measurement values was used as the fiber density of the sample. That is, the density of the number of fibers is used as the fiber density. In other words, the number of fibers per unit area in the cross section parallel to the thickness direction T is used as the fiber density. In addition, in terms of fiber density, the number of fibers per unit volume may also be used. The number of fibers per unit volume can be determined by analysis using X-ray CT, for example. Although the fiber density values per unit area and fiber density per unit volume are different, the relative comparison of fiber densities between fiber layers (for example, size comparison) yields the same result.

Furthermore, as shown in FIG. 3 , in this embodiment, part of the thermoplastic resin fibers F ₂ included in the second fiber layer 2 b are thermally fused to each other. That is, a part of the thermoplastic resin fibers F ₂ are joined to each other by heat fusion at the point where the thermoplastic resin fibers contact each other, and a matrix of the thermoplastic resin fibers F ₂ can be seen in the second fiber layer 2 b . In the sanitary napkin 1 having such a structure, the shape of the second fiber layer 2b can be stably maintained by a portion of the thermoplastic resin fibers _F2 that are thermally fused to each other in the second fiber layer 2b. The average fiber length of the water-retentive fibers F ₁ contained in the second fiber layer 2 b is relatively short, and the water-retentive fibers F ₁ can be stably held between (in the matrix of) the thermoplastic resin fibers F ₂ without bias. Thereby, the sanitary napkin 1 of this embodiment can move the liquid excretion attracted to the second fiber layer 2b to the absorbent body 4 (and the auxiliary sheet 5) without bias and stably, thereby exhibiting excellent functions. Absorption properties. In addition, the thermoplastic resin fibers _F2 of the sanitary napkin 1 may not be thermally fused to each other in this way.

Furthermore, as shown in FIG. 4 , in this embodiment, at least part of the thermoplastic resin fiber F ₂ of the second fiber layer 2 b is exposed on the skin-side surface of the first fiber layer 2 a. That is, the thermoplastic resin fiber F ₂ of the second fiber layer 2 b stably maintains the shape of the second fiber layer 2 b, and at least a part thereof is induced to continuously enter the inside of the first fiber layer 2 a from the second fiber layer 2 b, and These are further allowed to reach the skin-side surface of the first fiber layer 2a. The sanitary napkin 1 having such a structure can improve the water retention of the first fiber layer 2a because the thermoplastic resin fiber F2 of the second fiber layer _2b continuously extends into the inside of the first fiber layer 2a. The fibers F ₁ are stably held between the thermoplastic resin fibers F ₂ , so the average distance between the constituent fibers of the first fiber layer 2 a is relatively long, and collapse can be suppressed even when the strength of the first fiber layer 2 a is relatively weak. In addition, the water-retentive fiber _F1 of the first fiber layer 2a is held between the thermoplastic resin fibers _F2 , and is then covered with the melt _F2M of the thermoplastic resin fiber _F2 , so that the water-retentive property can be effectively suppressed. Fuzz occurs due to breakage of fiber _F1 . Therefore, the sanitary napkin 1 having such a structure can provide a better skin feel of the first fiber layer 2a of the surface sheet 2. Furthermore, a part of the thermoplastic resin fiber F ₂ that does not have water retention in the second fiber layer 2 b is present in the first fiber layer 2 a, because this can promote the flow of the thermoplastic resin fiber F ₂ from the first fiber layer 2 a to the first fiber layer 2 a. The second fiber layer 2b allows the liquid excrement to migrate stably to the absorbent body 4 (and the auxiliary sheet 5). In addition, the thermoplastic resin fiber F ₂ of the second fiber layer 2b of the sanitary napkin 1 does not need to be exposed on the skin-side surface of the first fiber layer 2a.

Furthermore, in this embodiment, the fibers constituting the surface sheet 2 are such that the fibers present at both ends of the surface sheet 2 in the width direction W are more oriented than the fibers present in the center portion of the surface sheet 2 in the width direction W. The longitudinal direction L of the surface sheet 2. That is, in the surface sheet 2 of this embodiment, the fibers present in the central portion in the width direction W have relatively smaller orientations in the longitudinal direction L, and the fibers present in both end portions in the width direction W have longer lengths. The orientation of the edge direction L becomes relatively larger. The sanitary napkin 1 having such a structure has a relatively arbitrary fiber orientation in the central portion of the surface sheet 2 in the width direction W. Therefore, in addition to being able to spread liquid excrement in a substantially concentric circle, it is also possible because At both ends of the surface sheet 2 in the width direction W, the fiber orientation is formed in the longitudinal direction L, so that liquid excretion reaching the both ends can be spread in the longitudinal direction L. That is, the sanitary napkin 1 can be used as a whole in the plane direction, and can exhibit more excellent absorption performance. In addition, at both ends of the surface sheet 2 in the width direction W, the number of fibers exposed from the end edges is small, so the friction on the wearer's skin is reduced and the skin feels smoother. In addition, the fiber orientation of the surface sheet 2 of the sanitary napkin 1 may be relatively large in the longitudinal direction L at both ends in the width direction W.

As shown in FIG. 1 , the sanitary napkin 1 has an excretion opening contact area XA set slightly forward of the central portion in the longitudinal direction L when viewed from above, that is, at the central portion in the width direction W. The excretion port contact area XA is an area that faces or contacts the wearer's excretion port when the sanitary napkin 1 is installed, and is generally set according to the type and use of the absorbent article. The excretion port contact area XA is, for example, slightly forward of the central portion of the absorbent body 4 in the longitudinal direction L, and is set to about 1/4 to 1/2 of the total length of the absorbent body 4 in the longitudinal direction L. The length is set to a width of about 1/2 to 1/3 of the entire length of the absorber 4 in the width direction W at a position substantially in the center of the absorber 4 in the width direction W. In addition, when the absorbent article is equipped with wings as in the above-mentioned sanitary napkin 1, the excretion opening contact area is generally set to overlap with the wings in the width direction. For example, the excretion opening contact area can be set to this The center position of the excretion port contact region in the longitudinal direction and the center position of the wing portion in the longitudinal direction substantially overlap in the width direction.

(pressing section) In this embodiment, as shown in FIG. 1 , the sanitary napkin 1 has two outer sides located in the width direction W with respect to the excretion port contact area XA, and extends continuously or intermittently in the longitudinal direction L. There are a pair of pressing sections (pressing grooves) 12 and 12 . Moreover, as shown in FIG. 1 , in this embodiment, the sanitary napkin 1 further includes: a sanitary napkin 1 located on the rear side of each of the pair of pressing parts 12 and 12 in the longitudinal direction L and extending in the longitudinal direction L. A pair of pressing parts (pressing grooves) 13, 13; a pressing part (pressing part) having a heart-shaped annular shape and located on each of the front side and the rear side in the longitudinal direction L with respect to the discharge port abutment area XA. grooves) 11, 14; and a plurality of point-shaped pressing parts 15 in the discharge port abutment area XA.

These pressed parts 11 to 15 are formed by pressing the surface sheet 2 and the absorbent body 4 in the thickness direction T by processing means such as embossing. That is, the surface sheet 2, the auxiliary sheet 5, and the absorbent body 4 (specifically, the core covering 4b and the absorbent core 4a on the skin side of the absorbent body 4) are pressed in the thickness direction T and are formed. As shown in FIG. 2 , each pressed part has a low-density part LPA that is formed at a shallow depth from the surface of the skin side of the surface sheet 2 and has a relatively low fiber density when pressed, and a low-density part LPA that is strongly pressed and formed The high-density portion HPA is formed at a deep position from the skin-side surface of the surface sheet 2 and has a relatively high fiber density. These low-density part LPA and high-density part HPA may also be called the bottom of the shallow depth position and the bottom of the deep depth position in each press section. As shown in FIG. 2 , although the low-density part LPA and the high-density part HPA of the press parts 11 to 15 are located in the absorbent core 4a, the high-density part HP can also reach the non-skin side core cladding 4b.

In addition, the shape of the press sections 11 to 15 is not particularly limited, and any shape can be adopted according to desired liquid diffusivity, deformation induction, strength, etc.

Moreover, the sanitary napkin 1 does not need to have such pressing parts 11 to 15, but it is preferable to have at least one of the pressing parts 11 to 15. If the sanitary napkin 1 (more specifically, the surface sheet 2) has a pressed portion recessed from the surface on the skin side toward the thickness direction T, the pressed portion can hold the water-retentive fiber F ₁ in the surface sheet 2 more easily. The above-mentioned fluffing of the water-retentive fiber _F1 occurs.

Furthermore, in this embodiment, at least a part of the thermoplastic resin fiber F ₂ of the second fiber layer 2 b is exposed on the inner surface of at least one of the press sections 11 to 15 . If the sanitary napkin 1 has such a structure, the thermoplastic resin fiber F ₂ is exposed in the first fiber layer 2a on the surface inside the press section. This allows the first fiber layer 2a to be used even in the press section. The water-retaining fiber F ₁ of 2a is stably held between the thermoplastic resin fibers F ₂ . Thereby, fluff caused by the water-retentive fiber F ₁ is less likely to occur even in the press section, and the first fiber layer 2a in the press section can have a better skin feel. Furthermore, because part of the thermoplastic resin fiber F ₂ that does not have water retention in the second fiber layer 2 b exists in the first fiber layer 2 a, this can promote the removal of the first fiber from the press section through the thermoplastic resin fiber F ₂ Since the liquid excrement moves from the layer 2a to the second fiber layer 2b, the liquid excrement can be transferred to the absorbent body 4 (and the auxiliary sheet 5) more stably. In addition, in the sanitary napkin 1 for sanitary use, the thermoplastic resin fiber F ₂ may not be exposed on the inner surface of the press section.

Furthermore, in this embodiment, at least a part of the thermoplastic resin fiber F ₂ of the second fiber layer 2 b is exposed on the surface of the low density portion LPA of at least one of the press sections 11 to 15 of the press section. If the sanitary napkin 1 has such a structure, the thermoplastic resin fiber F ₂ is exposed in the first fiber layer 2a on the surface of the low-density part LPA, thereby allowing the first fiber in the low-density part LPA to The water-retentive fibers F ₁ of the layer 2 a are stably held between the thermoplastic resin fibers F ₂ . Thereby, even in the low-density part LPA, fluffing due to the water-retentive fiber F ₁ is less likely to occur, and the first fiber layer 2a in the low-density part LPA can have a better skin feel. Furthermore, a part of the thermoplastic resin fiber F ₂ that does not have water retentivity in the second fiber layer 2 b is present in the first fiber layer 2 a in the low-density part LPA, because it can promote the flow of the thermoplastic resin fiber F ₂ from the second fiber layer 2 b. The liquid excreta moves from the first fiber layer 2a to the second fiber layer 2b in the low-density part LPA, so the liquid excrement can be transferred to the absorbent body 4 (and the auxiliary sheet 5) more stably. In addition, in the sanitary napkin 1 for sanitary use, the thermoplastic resin fiber _F2 may not be exposed on the surface of the low-density part LPA.

(concave-convex structure) In this embodiment, the surface sheet 2 has an uneven structure as shown in FIG. 4 . As shown in FIG. 4(b) , the first fiber layer 2a has a first upper surface 2aE on the upper side (skin side) in the thickness direction T and a first lower surface 2aF on the lower side (non-skin side). The second fiber layer 2b has a thickness The second upper surface 2bE on the upper side and the second lower surface 2bF on the lower side in the direction T. Although the first lower surface 2aF of the first fiber layer 2a and the second upper surface 2bE of the second fiber layer 2b are virtual boundaries between the two fiber layers, part of the fibers of the two fiber layers enter each other through entanglement. Fibrous layer, so not a fine border.

Furthermore, the first fiber layer 2a has a plurality of layers that extend continuously along the longitudinal direction L and are arranged at predetermined intervals in the width direction W so that the first upper surface 2aE protrudes upward (skin side). The convex portions 21 and a plurality of recessed portions 22 extend continuously along the longitudinal direction L and are arranged between adjacent convex portions 21 so that the first upper surface 2aE is recessed downward (non-skin side). If the surface sheet 2 has such a specific uneven structure including a plurality of convex portions 21 and a plurality of concave portions 22, the contact area between the skin-side surface of the surface sheet 2 and the wearer's skin becomes smaller, so that the surface sheet 2 can be replaced. The possibility of causing uncomfortable irritation to the wearer's skin due to fluffing of the thermoplastic resin fiber F ₂ and the water-retentive fiber F ₁ contained in the surface sheet 2 is further reduced.

In addition, in this embodiment, each of the plurality of convex portions 21 has a solid structure as shown in FIG. 4(b) . In this way, if each of the plurality of convex parts 21 has a solid structure, each convex part 21 is less likely to collapse, and at the same time, liquid migration from each convex part 21 that easily contacts the wearer's body toward the absorbent body 4 is excellent, so that it can The dryness of the surface of each convex part 21 is improved.

On the other hand, the second fiber layer 2b has a substantially flat structure except for the recessed portion 23 described below formed by pressing. However, the second upper surface 2bE of the second fiber layer 2b may be slightly raised upward in the thickness direction T at a position corresponding to the convex portion 21. In addition, the second fiber layer 2b may have a structure that, like the first fiber layer 2a (but in the opposite direction to the thickness direction T), extends continuously along the longitudinal direction L and is arranged at a predetermined interval in the width direction W. The second lower surface 2bF has a plurality of convex portions that protrude downward (non-skin side) and extend continuously along the longitudinal direction L, and are arranged between adjacent convex portions so that the second lower surface 2bF 2bF is a plurality of recessed parts that are sunken upward (skin side). At this time, it is ideal that the positions of the convex portions 21 and the concave portions 22 of the first fiber layer 2a correspond to the positions of the convex portions and the concave portions of the second fiber layer 2b in the thickness direction T.

The first fiber layer 2a and the second fiber layer 2b are joined to each other by entanglement. As for the contacting method, for example, water acupuncture or water jetting can be used. However, the interlacing method is not limited to this example, and other interlacing methods such as the hot air method can also be used.

In addition, in this embodiment, let the fiber density of the top 21T of the convex part 21 be S1, let the fiber density of the bottom 22B of the recessed part 22 be S2, and let the fiber density between the top 21T of the convex part 21 and the bottom 22B of the recessed part 22 be S2. When the fiber density of the region MP is set to S3, the relationship of S1<S3<S2 is satisfied. If the sanitary napkin 1 has such a structure, in the surface sheet 2, it is easy to pass from the top 21T of the convex portion 21 with a sparse (low density) fiber density S1 through the area with a medium (medium density) fiber density S3. MP operates capillary action toward the bottom 22B of the concave portion 22 having a dense (high density) fiber density S2, so that MP can be excreted to the skin-most surface of the surface sheet 2 (that is, the top 21T of the convex portion 21 or the vicinity thereof) is further likely to be induced to the bottom 22B of the recessed portion 22 located near the surface of the surface sheet 2 on the non-skin side. This allows liquid excretion to move more stably from the skin-side surface of the top sheet 2 to the absorbent body 4 (and the auxiliary sheet 5 ) via the non-skin-side surface of the top sheet 2 . In addition, the surface sheet 2 has the above-mentioned fiber density gradient (S1<S3<S2), so that the liquid excretion once absorbed is less likely to flow back, and furthermore, the fiber density of the convex portion 21 is low, because It can provide the wearer with a soft touch, so the surface sheet 2 can not only make the skin feel good, but also improve the absorption performance. In addition, the sanitary napkin 1 does not need to have the above-mentioned uneven structure in the surface sheet 2, nor does it need to have the above-mentioned fiber density gradient.

Moreover, in this embodiment, the surface sheet 2 has the first fiber layer 2a and the second fiber layer 2b compressed in the thickness direction T by processing means such as embossing in each of the plurality of recessed portions 22 as shown in FIG. 4 a plurality of recessed portions 23. The plurality of recessed portions 23 are arranged intermittently along the longitudinal direction L in each recessed portion 22 at equal or non-equal intervals. In addition, the recessed portions 23 may or may not be arranged on the same straight line in the longitudinal direction L of the recessed portions 22 adjacent to the width direction W. In this embodiment, the plurality of recessed portions 23 are arranged in a checkered pattern relative to the recessed portion 22 as shown in Fig. 4(a) . In addition, the plan view shape of each of the plurality of recessed portions 23 is not particularly limited. It may be an ellipse like this embodiment, or may be any other shape. If the sanitary napkin 1 has such a structure, the first fiber layer 2a and the second fiber layer 2b are fixed in the thickness direction T by pressing in each of the plurality of recessed portions 23 (that is, the first fiber layer 2a is compressed The water-retentive fiber F ₁ ), thereby making fluff caused by the water-retentive fiber F ₁ less likely to occur, and the skin feel of the surface sheet 2 can be better maintained. In addition, the sanitary napkin 1 does not need to have such a plurality of recessed portions 23 in the surface sheet 2 .

(auxiliary sheet) In this embodiment, as shown in FIG. 1 , the auxiliary sheet 5 has a structure extending in the longitudinal direction L from the longitudinal end on the front side of the sanitary napkin 1 across the longitudinal end on the rear side when viewed from above. Approximately rectangular shape when viewed from above. The auxiliary sheet 5 is composed of a liquid-permeable sheet-like member, and is disposed between the surface sheet 2 and the absorbent body 4 in the thickness direction T of the sanitary napkin 1 as shown in FIG. 2 to allow the liquid to pass through the surface. The liquid excretion from the sheet 2 moves to the absorbent body 4 on the non-skin side.

The liquid-permeable sheet-like member that can be used as the auxiliary sheet 5 is not particularly limited as long as the effects of the present invention are not hindered. Examples include liquid-permeable nonwoven fabrics, woven fabrics, composite sheets laminated with these, etc. .

In this embodiment, the auxiliary sheet 5 located on the non-skin side of the surface sheet 2 and each of the plurality of recessed portions 22 of the surface sheet 2 (more specifically, the second lower surface 2bF corresponding to each of the recessed portions 22) are connected by an adhesive. They are joined by any joining means such as heat fusion means or the like. In this way, if the auxiliary sheet 5 and the surface sheet 2 are joined to each other at each of the plurality of recessed portions of the surface sheet 2, the joint portion of the auxiliary sheet 5 and the surface sheet 2 retains the water-retentive fiber F ₁ , and the above-mentioned water retention becomes less likely to occur. Fuzzing of sexual fibers.

Furthermore, as shown in FIG. 2 , the auxiliary sheet 5 in this embodiment has a slightly larger shape in the width direction W than the surface sheet 2 , and a pair of rings are formed at both ends in the width direction W. Part 5L, 5L. The pair of ring portions 5L, 5L are formed so that both ends of the auxiliary sheet 5 in the width direction W are oriented inward in the width direction W of the auxiliary sheet 5 and toward the non-skin side (lower side in the thickness direction T). ) is formed by folding it into a ring shape. Both ends of the folded auxiliary sheet 5 are sandwiched between the surface sheet 2 and the pair of side sheets 6, 6, and the pair of inner end portions facing the pair of side sheets 6, 6 pass through A pair of joint portions (not shown) extending intermittently or continuously along the longitudinal direction L are joined to each other. In addition, the ring portion 5L does not contain an elastic member. In addition, each of the two ends of the folded auxiliary sheet 5 is formed by the inner surfaces of the ring portion 5l (that is, the non-skin side surfaces of the auxiliary sheet 5 before folding) along the longitudinal direction. A pair of connecting portions extending intermittently or continuously are joined to each other.

Normally, if the edge of a surface sheet containing many water-retaining fibers is worn, the water-retaining fibers will easily loosen and fall off from the edge. However, in this embodiment, the size of the auxiliary sheet 5 in the width direction W becomes larger than that of the surface sheet. The size of the surface sheet 2 in the width direction W is larger. That is, when viewed from above, the portion of the auxiliary sheet 5 that is further outward than the two end edges of the surface sheet 2 in the width direction W faces the width direction W. The outer side extends to form a pair of extended portions. Furthermore, as the pair of extended portions, the pair of ring portions 5L and 5L are formed at both ends of the auxiliary sheet 5 in the width direction W. 5L, therefore, the sanitary napkin 1 can withstand the force received from the wearer's thighs at the pair of ring portions 5L, 5L (a pair of extended portions), and can adjust the width direction of the surface sheet 2 Both end edges of W are less likely to rub against the thighs, and the above-mentioned water-retentive fiber F ₁ is less likely to loosen and fall off from both end edges of the surface sheet 2 in the width direction W. Furthermore, if a pair of ring portions 5L, 5L are used as the pair of extension portions, the cushioning effect of the pair of ring portions 5L, 5L can be used to softly receive the sanitary napkin 1 from the wearer's body. The force exerted on the thigh can make the wearer feel better. In particular, when the water-retentive fiber _F1 is cotton fiber, the effect is remarkable.

Moreover, in this embodiment, the auxiliary sheet 5 has a fiber density higher than the fiber density of the second fiber layer 2b. If the sanitary napkin 1 has such a structure, the liquid excrement attracted to the second fiber layer 2b can be made to move to the auxiliary sheet 5 more stably via capillary action, so the liquid excrement can be removed from the surface. The sheet 2 moves to the absorbent body 4 more stably via the auxiliary sheet 5. As a result, the surface sheet 2 has a good skin feel and the absorption performance is improved. In addition, the sanitary napkin 1 does not need to be equipped with the auxiliary sheet 5 or the ring part 5L.

Furthermore, when the surface sheet 2 contains water-retentive fibers F ₁ and the surface sheet 2 contains cellulose fibers (ideally cotton fibers), the auxiliary sheet 5 preferably contains cellulose fibers (ideally cotton fibers). If the sanitary napkin 1 has such a structure, the water-retaining fiber F ₁ with high liquid diffusivity is preferably a cellulose fiber, and more preferably a cotton fiber. The first fiber layer 2 a of the surface sheet 2 passes through the second fiber. Since the layer 2 b is connected to the auxiliary sheet 5 , liquid diffusion of liquid excrement caused by these fibers allows the liquid excrement to move from the surface sheet 2 to the absorbent body 4 via the auxiliary sheet 5 more stably. , As a result, the skin touch of the surface sheet 2 is good, and the absorption performance can be further improved. In addition, the sanitary napkin 1 and the auxiliary sheet 5 may not contain water-retaining fiber, cellulose fiber or cotton fiber. At this time, as the auxiliary sheet 5, for example, a nonwoven fabric made of thermoplastic resin fibers can be used.

In addition, in the present invention, the size, shape, thickness, etc. of the auxiliary sheet are not particularly limited as long as they do not hinder the effects of the present invention, and any size, shape, thickness, etc. that correspond to the desired absorption performance, softness, etc. can be adopted. .

(Absorbent body) In the above-mentioned embodiment, as shown in FIG. 1 , the absorbent body 4 spans each of the longitudinal center line _CL and the widthwise center line _CW in the sanitary napkin 1 when viewed from above. A wide range extends in the longitudinal direction L and the width direction W, and both end portions in the longitudinal direction L each have a vertically elongated plan view shape protruding in an arc toward the outer side of the longitudinal direction L. Such an absorbent body 4 is formed of a water-absorbent member as shown in FIG. 2 and is arranged between the surface sheet 2 and the back sheet 3 (more specifically, in the thickness direction T of the sanitary napkin 1 Between the auxiliary sheet 5 and the back sheet 3), liquid excretions such as menstrual blood that have passed through the surface sheet 2 can be absorbed and held, and have predetermined liquid absorption performance and liquid retention performance.

In the present invention, the water-absorbent member that can be used as an absorber is not particularly limited as long as it can absorb and hold at least liquid excretions such as menstrual blood, and any water-absorbent member known in this field can be used. Examples of such a water-absorbent member include one in which at least one absorbent core made of any water-absorbent material is covered with a core-covering sheet such as hydrophilic tissue. Examples of the water-absorbent material constituting the absorbent core include hydrophilic fibers, superabsorbent polymers, and the like, and more specifically, cellulose-based materials such as ground pulp, cotton, rayon, and acetate. Fibers; granules made of superabsorbent polymers such as sodium acrylate copolymer; and mixtures of any combinations thereof, etc.

In the above-described embodiment, the absorbent body 4 is composed of an absorbent core 4a formed of a water-absorbent material and a core covering 4b covering the absorbent core 4a. Furthermore, when the surface sheet 2 contains cellulose-based fibers (ideally cotton fibers), it is preferable that the absorbent body 4 contains cellulose-based fibers (ideally cotton fibers) corresponding to the surface sheet 2 . At this time, it is preferable that part of the cellulose fibers contained in the surface sheet 2 come into contact with the cellulose fibers contained in the absorber 4 . If the sanitary napkin 1 has such a structure, the water-retentive fibers with high liquid diffusivity are connected from the first fiber layer 2a of the surface sheet 2 through the second fiber layer 2b (in some cases, through the auxiliary sheet 5). Therefore, the liquid excrement can be directly diffused from the surface sheet 2 to the absorbent body 4 by utilizing the liquid diffusion of the liquid excrement caused by the cellulose-based fibers. As a result, the absorption performance can be further improved. In addition, the absorbent body 4 of the sanitary napkin 1 may not contain cellulose fibers or cotton.

In the present invention, there are no particular restrictions on the shape of the absorbent body when viewed from above, various dimensions, basis weight, etc., as long as the user can use the absorbent body as an absorbent article, and any shape corresponding to the desired absorption performance, softness, strength, etc. can be used. Any top view shape (for example: rectangle, oval, hourglass shape, etc.), various sizes, basis weight, etc.

Furthermore, in the present invention, if the absorbent article has a predetermined absorptive performance as the absorbent article as a whole through components other than the absorber (for example, a surface sheet), the absorbent article does not necessarily need to include such an absorber.

(Side slice) In the above-described embodiment, the pair of side sheets 6 and 6 has a pair of side sheets 6 and 6 extending in the longitudinal direction L at both ends of the sanitary napkin 1 in the width direction W when viewed from above, as shown in FIG. 1 . Right ribbon shape. The pair of side sheets 6, 6 are formed of hydrophilic or water-repellent sheet-like members, and both ends of the side sheets 6 and 6 in the width direction W of the sanitary napkin 1 are located on the non-skin side of the surface sheet 2. The liquid excretion supplied to the skin-side surface of the surface sheet 2 is blocked so as not to leak to the outer side of the sanitary napkin 1 in the width direction W, and is diffused in the longitudinal direction L. Function.

The hydrophilic or water-repellent sheet-like member that can be used as the side sheet 6 is not particularly limited as long as it can function as the side sheet. Examples thereof include nonwoven fabrics made of hydrophilic or water-repellent fibers, hydrophilicized ones, etc. Treated or water-splashed non-woven fabrics, breathable synthetic resin films, etc.

Furthermore, in the sanitary napkin 1 of this embodiment, the dynamic friction coefficient of the pair of side sheets 6 and 6 when wet is lower than the dynamic friction coefficient of the top sheet 2 when wet. The pair of side sheets 6, 6 that easily come into contact with the wearer's leg skin have a lower dynamic friction coefficient than the above-mentioned surface sheet 2 that has a better skin feel, and can provide the sanitary napkin 1 with a smoother feel. skin touch.

Here, the dynamic friction coefficient when wet can be measured according to the following method. (1) Cut the surface sheet and side sheet of the absorbent article, and take a sample of 40 mm in the width direction and 80 mm in the length direction. In addition, when these sheets cannot be separated due to an adhesive such as a hot melt material (HMA) type adhesive, the adhesive is washed away with toluene and then dried in the air for 24 hours. (2) The 10 mm end of each sample in the longitudinal direction is fixed to a horizontal board using tape (Asoko Co., Ltd.: "work site tools" cloth tape 0.26 mm thickness width 50 mm × length 25 m roll). (3) On each sample, a digital lateral force gauge (FGP-0.5 (FGP-2) from Nidec Corporation, Taiwan) was installed and a wide muslin cloth (50mm × 40mm, based on JIS L 0803 Added white cloth for dyeing fastness test, Japan Standards Association, single fiber cloth). Furthermore, a 525-g weight of a rectangular parallelepiped with a base of 35 mm × 25 mm is placed thereon. (4) Let the wide-width muslin cloth that is roughly evenly moistened with a predetermined amount of ion-exchange water move on the sheet for 30 mm at a speed of 100 mm/minute, and take the maximum value displayed at this time as the dynamic friction coefficient. At this time, the wide muslin cloth was allowed to touch the surface of the skin side of each sample. In this measurement method, a wide-width muslin cloth is wetted to reproduce the user's wet skin. Furthermore, the reproduced skin moisture content is based on 60% of the moistened state. Therefore, the predetermined amount of ion-exchange water is 60% by mass relative to the mass of the wide muslin cloth. Specifically, when the 40mm × 50mm wide muslin cloth is 50g/m ^2, it is 0.06mL (50g/m ² × 0.04m × 0.05m × 60%). In addition, when it is not possible to collect slices using the width dimensions mentioned above, samples are collected at the maximum width that can be collected and measured. Then, place a weight of 30g/ ^cm2 within the area of the sheet, and a wide muslin cloth with a weight width + 10mm (the connection part of the digital side force meter), and press the weight on the sheet at a speed of 100mm/min. Move the maximum distance, and use the maximum value displayed at this time as the kinetic friction coefficient.

Furthermore, in this embodiment, the dynamic friction coefficient of the surface sheet 2 when wet is 0.80, and the dynamic friction coefficient of the side sheet 6 when wet is 0.49. In addition, the difference between the dynamic friction coefficient of the surface sheet 2 and the dynamic friction coefficient of the side sheet 6 may be, for example, 0.1 or more and 0.25 or less. If the difference in dynamic friction coefficient is within this range, the wearer will easily feel the difference in the surface properties of the surface sheet 2 and the side sheet 6 .

In addition, such a pair of side sheets 6, 6 with a low dynamic friction coefficient can be formed by using a low-friction material as the material for forming the side sheets 6, 6 (for example, the constituent fibers of a nonwoven fabric, etc.), or by using a low-friction material as a material. The side sheet is formed by coating the skin-side surface of a well-known sheet-like member with a low-friction material. In addition, the low-friction material that can be used for the side sheets is not particularly limited, and examples thereof include friction-resistant materials such as olefin-based resins such as polyethylene and polypropylene; silicone resins; and fluororesins such as polytetrafluoroethylene. Resins with low coefficients; resin compositions containing such resins, etc. In addition, the dynamic friction coefficient of the pair of side sheets 6 and 6 when wet may not be lower than the dynamic friction coefficient of the surface sheet 2 when wet.

In the present invention, there are no particular restrictions on the planar view shape and various sizes of each pair of side sheets that can be used as side sheets of an absorbent article. Any shape corresponding to the desired leakage prevention performance, absorptive performance, etc. can be used. Look down to see shapes, various sizes, and more.

In addition, the absorbent article is provided with such a pair of side sheets because it is not an essential component of the absorbent article of the present invention. Therefore, the absorbent article does not need to be provided with such a pair of side sheets.

(thin slices inside) In the sanitary napkin 1 of the above-mentioned embodiment, the back sheet 3 has a vertically long plan view shape in a plan view as shown in FIG. The longitudinal end portions of the two sides extend in the longitudinal direction L, and extend from the width direction end portion of one side in the width direction W of the sanitary napkin 1 across the width direction end portion of the other side in the width direction. W extension exists. Such back sheet 3 is composed of a liquid-impermeable sheet-like member as shown in FIG. 2. It is arranged at a position other than the skin side in the thickness direction T of the sanitary napkin 1 and prevents the absorbent body 4 or The liquid excretion exuded from the absorbent body 4 leaks to the outside of the sanitary napkin 1 and functions.

The liquid-impermeable sheet-like member that can be used as the back sheet 3 can prevent the penetration of liquid excretions such as menstrual blood discharged from the wearer and prevent the excretion from leaking into the wearer's clothing. There are no particular restrictions on those that can function in clothing, etc. For example, any hydrophobic thermoplastic resin fiber (for example, polyolefin fiber such as PE, PP, etc.; polyethylene terephthalate (PET)) can be used. ) and other polyester fibers; various composite fibers such as core-sheath type composite fibers, etc.); hydrophobic nonwoven fabrics made of hydrophobic thermoplastic resins such as PE and PP; porous or non-porous resin films made of hydrophobic thermoplastic resins such as PE and PP ; A laminate in which a nonwoven fabric is bonded to the resin film; any liquid-impermeable sheet-like member such as a laminated nonwoven fabric such as SMS nonwoven fabric.

In addition, there are no particular restrictions on the top view shape, various sizes, basis weight, etc. of the back sheet 3 as long as it can be used as the back sheet, and any shape can be adopted according to the desired leakage prevention performance, breathability, strength, etc. Shapes, various sizes, basis weights, etc.

In addition, in the sanitary napkin 1 of this embodiment, the surface sheet 2 is joined to the auxiliary sheet 5 by an adhesive or the like (for example, a hot-melt adhesive, etc.), and the auxiliary sheet 5 and a pair of side sheets 6, 6 The portions facing the absorber 4 in each of them are bonded to the absorber 4 with an adhesive or the like, and the portions facing the back sheet 3 in each of the pair of side sheets 6, 6 and the absorber 4 The sheet 3 is joined to the inner surface by an adhesive or the like.

(adhesion part) In this embodiment, the sanitary napkin 1 is further equipped with a means for fixing the sanitary napkin 1 to the wearer's clothing (such as underwear, etc.) on the non-skin side surface of the back sheet 3 as shown in FIG. 2 A plurality of adhesive parts 7 and a pair of adhesive parts 8, 8. The plurality of adhesive portions 7 are arranged on the non-skin side surface of the back sheet 3 so as to overlap the absorber 4 in the thickness direction T, and have a plurality of adhesive portions 7 that continuously extend in the longitudinal direction L and are intermittently arranged in the width direction W. A plan view shape of a plurality of strips (a plurality of substantially rectangular shapes). In addition, the pair of adhesive portions 8 and 8 and the pair of wing portions 9 and 9 are arranged on the non-skin side surface of the back sheet 3 so as to overlap in the thickness direction T, and have a rough shape extending continuously in the longitudinal direction L. Rectangular shape when viewed from above.

In addition, the adhesive portions 7 and 8 are not particularly limited as long as they can respectively fix the sanitary napkin 1 to the wearer's underwear. For example, they can be formed by any adhesive such as styrene polymer.

In addition, the absorbent article is provided with such an adhesive portion because it is not an essential component of the absorbent article of the present invention. Therefore, the absorbent article does not need to have such an adhesive portion.

[Manufacturing method] Next, a method for manufacturing the surface sheet 2 of the sanitary napkin 1 according to the above embodiment will be described with an example.

(Second fiber web formation process) First, the water-retentive fiber F ₁ and the thermoplastic resin fiber F ₂ used to form the second fiber layer 2b are supplied to the first carding machine (for example, a single carding machine or a double carding machine is used) dry roller carding machine) to form a second fiber web corresponding to the second fiber layer 2b. Such a second fiber web is conveyed in the conveying direction MD by the conveying device.

(First fiber web forming process) Next, the water-retentive fiber F ₁ used to form the first fiber layer 2a is supplied to the second card (the same dry roller card as the first card) to form a corresponding The first fiber web of the first fiber layer 2a.

(Fibre web lamination process) The formed first fiber web is laminated on the second fiber web being transported by the transport device. Thereby, a composite fiber web having a two-layer structure in which the first fiber web and the second fiber web are laminated is formed. In addition, the ratio of each fiber in each fiber web can be controlled by the ratio of raw fibers supplied to each carding machine.

(Intertwining process) Next, the composite fiber web with a two-layer structure is subjected to water jet treatment by a water jet treatment machine, so that the fibers in the composite fiber web are water-interconnected with each other. Thereby, a composite fiber sheet (water-needle nonwoven fabric) is formed. In this way, the fibers in the composite fiber network are integrally intertwined with each other by the entanglement of water flow. In addition to being less likely to loosen and fall off the water-retentive fibers F ₁ such as cotton fibers, it is also easy to obtain a good skin feel.

Here, in the above-mentioned water jet treatment, a high-pressure jet water stream is sprayed from the upper side of a composite fiber web placed on a continuously moving mesh belt, and the fibers in the composite fiber web are intertwined with each other by the action of the water stream. In addition, the properties of the composite fiber sheet obtained by water jet treatment can be appropriately adjusted by the quality of each fiber web, the hole diameter of the jet nozzle, the number of holes (spacing) of the jet nozzle, the moving speed of the fiber web, etc.

In addition, the method of forming the fiber web corresponding to each fiber layer is not limited to the above-mentioned method, and for example, a wet method may also be used. In addition, the method of joining the fabrics is not limited to the above-mentioned method. For example, the hot air method may also be used (that is, the composite fiber web is transported to a heating device, and the fibers in the composite fiber web are heated by heating the air in the heating device. methods of interacting with each other), acupuncture, etc.

(drying project) The composite fiber sheet that has passed through the water jet processor is transported to a dryer (heated hot air oven) and dried with hot air.

(Heat treatment process) Furthermore, the dried composite fiber sheet is transported to a heat treatment device (heating hot air furnace), and is heated by hot air at a predetermined temperature. By this heat treatment, at least part of the thermoplastic resin fiber F ₂ in the composite fiber sheet is melted, and the melt F _2M flows in the composite fiber sheet and adheres to the water retention property present in the portion corresponding to the first fiber layer 2 a Fiber F ₁ , water-retentive fiber F ₁ in the interlaced portion _PE in the composite fiber sheet, etc. Thereby, at least a part of the water-retentive fibers F ₁ contained in the portion corresponding to the first fiber layer 2 a is at least a part of the intertwined portions _PE of _the fibers, by the thermoplastic resin fiber F ₂ Melt F _2M is coated.

In addition, the heat treatment conditions are not particularly limited as long as the thermoplastic resin fiber F ₂ can be melted. However, when the thermoplastic resin fiber F ₂ is a composite fiber such as a core-sheath type composite fiber or a parallel type composite fiber, Adopt temperature conditions that melt only the resin component with a low melting point exposed on the surface of the composite fiber (for example, the resin component constituting the sheath in the case of a core-sheath type composite fiber, or the resin component on one side in the case of a side-by-side type composite fiber). for ideal. In addition, the above-mentioned drying after the water jet treatment may be used in combination with a device suitable for the subsequent heat treatment (that is, a dryer and a heat treatment device).

(shaping project) Next, the heat-treated composite fiber sheet is supplied to the forming device while being conveyed in the conveying direction MD. Here, the shaping device is provided with a pair of shaping rollers, which extend in the circumferential direction on the outer peripheral surface and have concave portions and convex portions that mesh with each other. The heat-treated composite fiber sheet is clamped between the pair of shaping rollers. The above-mentioned specific uneven structure extending in the conveyance direction MD is formed between the recessed portion and the convex portion. In addition, when the surface sheet 2 does not have such a specific uneven structure, the shaping process may be omitted. In this way, the composite fiber shaped sheet for the surface sheet 2 is formed. In addition, the composite fiber shaped sheet is laminated with sheet-like members for other constituent members of the sanitary napkin 1 and then cut into the shape of the sanitary napkin 1 to become the surface sheet 2 .

In addition to the sanitary napkins of the above embodiments, the present invention is applicable to various absorbent articles such as sanitary pads, (light) incontinence pads, and disposable diapers. In addition, the absorbent article of the present invention is not limited to the above-mentioned embodiments, examples described below, etc., and appropriate combinations, substitutions, changes, etc. can be made within the scope that does not deviate from the object and purpose of the present invention.

In addition, the nonwoven fabric including the first fiber layer and the second fiber layer used for the surface sheet of the absorbent article of the present invention is less likely to cause uncomfortable stimulation to the user's skin and is a nonwoven fabric with excellent skin touch. Therefore, it is also It can be applied to other sheet-like members that require a good skin feel (such as side sheets, exterior sheets, etc.), and can also be used in hygiene products other than absorbent articles (such as masks, dirt wiping sheets, face masks, etc.) , cosmetic sheets, powder puffs (such as cotton puffs), etc.). When applied to such nonwoven fabric, the nonwoven fabric has a first side and a second side, The nonwoven fabric has: a first fiber layer, which contains water-retentive fibers and forms the first side of the non-woven fabric; and a second fiber layer that includes thermoplastic resin fibers and water-retentive fibers and is adjacent to the second surface side of the first fiber layer to form the second surface of the nonwoven fabric, The proportion of the water-retentive fibers among the fibers constituting the first fiber layer is greater than the proportion of the water-retentive fibers among the fibers constituting the second fiber layer, At least a part of the water-retentive fibers included in the first fiber layer is coated with a melt of the thermoplastic resin fiber in at least a part of the intersection parts of the fibers. [Example]

Hereinafter, although Examples and Comparative Examples are given to illustrate the present invention more specifically, the present invention is not limited to these Examples.

A surface sheet that can be used for the absorbent article of the present invention (Example) and a surface sheet that does not meet the structural requirements of the present invention (Comparative Example) were produced, and the occurrence of fluffing was verified.

Example 1 First, cotton fibers (fiber length 5 mm to 35 mm, basis weight 16 g/m ² ) and core-sheath type composite fibers (core: PP) were prepared as water-retentive fibers and thermoplastic resin fibers for forming the second fiber layer, respectively. , Sheath part: PE, fiber length 38mm, basis weight 4g/m ² ), these fibers are supplied to the first carding machine to form a second fiber web corresponding to the second fiber layer (second fiber web formation process) . The mixing ratio (mass ratio) of cotton fibers and core-sheath type composite fibers in the second fiber web is cotton fiber: core-sheath type composite fiber = 60:40. Next, only cotton fiber (fiber length 20 mm to 35 mm, basis weight 10 g/m ² ) is prepared as the water-retentive fiber for forming the first fiber layer, and such cotton fiber is supplied to the second carding machine to form a fiber corresponding to the first fiber layer. The first fiber web of the layer (the first fiber web formation process). Then, by laminating the formed first fiber web on the second fiber web being transported by the conveyor, a composite fiber web (fiber web) with a two-layer structure in which the first fiber web and the second fiber web are laminated is formed. After the web lamination process), such a composite fiber web is subjected to water jet treatment with a water jet treatment machine to allow the fibers in the composite fiber web to interact with each other with water flow to obtain composite fiber sheets (water-needle nonwovens) (interaction process). The composite fiber sheets that have passed through the water jet treatment machine are transported to a dryer (heated hot air oven) and dried with 70°C hot air (drying process). Furthermore, the dried composite fiber sheet is transported to a heat treatment device (heated hot air furnace), and is heated with hot air at 130°C, and the core-sheath type composite fiber melt ( Specifically, the sheath is coated (heat treatment process) with the molten PE material of the cotton fiber. Next, the heat-treated composite fiber sheet is supplied to a shaping device provided with a pair of shaping rollers having recessed portions and convex portions that mesh with each other, and is sandwiched between the recessed portions and convex portions of the pair of shaping rollers to form. A concave and convex structure extending in the conveyance direction MD (shaping process). In this way, the composite fiber-shaped sheet with the uneven structure was cut into a predetermined shape, and the surface sheet of Example 1 was obtained.

Comparative example 1 The surface sheet of Comparative Example 1 was obtained in the same manner as Example 1 except that the heat treatment process and shaping process were not performed.

Comparative Example 2 Only cotton fiber (fiber length 20 mm to 35 mm, basis weight 30 g/m ² ) was used as the fiber for forming the surface sheet (that is, the surface sheet was used as a fiber layer (cotton) with a single-layer structure without a second fiber layer). Fiber layer)), and the surface sheet of Comparative Example 2 was obtained in the same manner as Example 1, except that the heat treatment process and shaping process were not performed.

The surface sheet of Example 1 was observed using a scanning electron microscope to observe the inside of the first fiber layer, and it was confirmed that the core-sheath type composite fiber (thermoplastic resin fiber F ₂ ) was melted at the intersecting portion _PE between the fibers. (Specifically, it is a molten material of PE in the sheath) F _2M coated cotton fiber (water-retaining fiber F ₁ ). The confirmation results (that is, an electron micrograph of the first fiber layer in the surface sheet of Example 1) are shown in FIG. 5 .

Furthermore, for each surface sheet of Example 1, Comparative Example 1, and Comparative Example 2, the occurrence of fluff of each surface sheet was comparatively evaluated based on the following <Evaluation method of fluff due to friction fastness test>. Figure 6 shows the evaluation results (that is, comparative photographs showing the occurrence of fluff in Example 1 and Comparative Examples 1 and 2).

＜Evaluation method of fluff due to friction fastness test＞ (1) Cut out the measurement target area in a predetermined size (for example, 80 mm × 40 mm) from the nonwoven fabric constituting the surface sheet, and obtain a sample for measurement. (2) The measurement sample is fixed on the measurement platform of a dyed material friction fastness testing machine (manufactured by Daiei Science Seiki Co., Ltd.). (3) Install a 200g weight on the friction terminal of the dyeing material friction fastness testing machine, and stick the cloth patch forming the friction surface below. (4) Use the friction surface of the friction terminal to rub the surface of the measurement sample fixed on the measurement platform. At this time, the number of back and forth of the friction terminal is 100 times and 200 times, and the moving range (back and forth width) of the friction terminal is 60 mm. In addition, the so-called "0T", "100T" and "200T" items shown in Figure 6 refer to the number of back and forth of the friction terminal in the friction firmness test (FF) which are "0 times", "100 times" and "200 times". (5) Observe the fuzzing state on the surface of the measurement sample after rubbing with the friction terminal.

As shown in Figure 6, it can be seen that the surface sheet of Example 1, which was subjected to heat treatment and the intersecting portions of the cotton fibers were coated with the melt of the core-sheath type composite fiber, almost became fluffy even after being rubbed with a friction terminal 200 times. It did not occur, and the skin feels good (refer to the photo in column A in Figure 6). On the other hand, it was found that the surface sheets of Comparative Examples 1 and 2 that were not subjected to heat treatment were fluffed even if they were rubbed only 100 times with a friction terminal, and the skin touch was poor (see column B in Figure 6 (Comparison) Example 1) and photos in column C (Comparative Example 2)).

1: Sanitary napkin (an example of absorbent article) 2: Surface sheet 2a: 1st fiber layer 2b: 2nd fiber layer 3: Back sheet 4: Absorbent body 5: Auxiliary sheet 6: Side sheet F ₁ : Water retention Fiber F ₂ : Thermoplastic resin fiber P _E : Interlaced part F _2M : Melt

[Fig. 1] is a plan view of the sanitary napkin 1 according to one embodiment of the present invention as viewed in the thickness direction T from the surface sheet 2 side in an unfolded state. [Fig. 2] is a cross-sectional view along line II-II of the sanitary napkin 1 in Fig. 1. [Fig. [Fig. 3] is an enlarged schematic diagram of an important part of the first fiber layer 2a in the surface sheet 2. [Fig. 4] Fig. 4(a) is an enlarged plan view of the surface sheet 2, and Fig. 4(b) is a cross-sectional view along line IVb-IVb of the surface sheet 2 in Fig. 4(a). [Fig. 5] is an electron microscope photograph of the first fiber layer in the surface sheet of Example 1 of the present invention. [Fig. 6] A comparative photograph showing the occurrence of fluff in Example 1 of the present invention and Comparative Examples 1 and 2. [Fig.

2a: 1st fiber layer

F ₁ : Water-retaining fiber

F ₂ : Thermoplastic resin fiber

P _E : communication part

F _2M : Melt

Claims (13)

An absorbent article including a surface sheet, characterized in that the surface sheet includes: a first fiber layer containing water-retentive fibers and forming a skin-side surface of the surface sheet; and a second fiber layer , which contains thermoplastic resin fibers and water-retentive fibers, and forms the skin-side surface of the surface sheet adjacent to the non-skin side of the first fiber layer, and the proportion of the water-retentive fibers among the fibers constituting the first fiber layer The proportion of the water-retaining fibers in the fibers constituting the second fiber layer is greater than that of the water-retaining fibers in the first fiber layer, and at least a part of the water-retaining fibers contained in the first fiber layer is an entanglement of at least a part of the intersections between the fibers. The portion is coated with the melt of the thermoplastic resin fiber, and the proportion of the water-retentive fiber in the second fiber layer is 50 mass % to 90 mass % with respect to the total mass of all fibers constituting the second fiber layer. The absorbent article described in claim 1, wherein the thermoplastic resin fiber is one thermoplastic resin fiber entangled with a plurality of the water-retentive fibers, and the one thermoplastic resin fiber is intertwined with the plurality of the water-retentive fibers. the foregoing warranty Each intertwined portion of the water-based fiber is covered with a melt of the aforementioned thermoplastic resin fiber. In the absorbent article described in claim 1 or 2, the melt of the thermoplastic resin fiber is not exposed on the skin-side surface of the first fiber layer. The absorbent article according to claim 1, wherein the average fiber length of the water-retaining fibers contained in at least the first fiber layer is shorter than the average fiber length of the thermoplastic resin fibers. The absorbent article described in claim 1, wherein the average fiber length of the water-retaining fibers contained in at least the first fiber layer is 5 mm or more and less than 35 mm. In the absorbent article described in claim 1, the thermoplastic resin fiber is a composite fiber, and the composite fiber has a resin component with a low melting point exposed on the surface of the composite fiber. The absorbent article described in claim 1, wherein the surface sheet has a pressed portion recessed from the surface on the skin side toward the thickness direction. The absorbent article described in claim 1, wherein the surface sheet has a plurality of protrusions extending along the longitudinal direction of the absorbent article and located at intervals in the width direction of the absorbent article. portions, and a plurality of recessed portions extending along the longitudinal direction of the absorbent article and located between adjacent convex portions. The absorbent article described in claim 8, wherein the absorbent article further includes an auxiliary sheet located on the non-skin side of the surface sheet, and the surface sheet is formed between each of the plurality of recessed portions and the auxiliary sheet. Engagement. For example, in the absorbent article described in claim 1, the water-retentive fiber is organic cotton. In the absorbent article described in claim 1, the fiber density of the second fiber layer is greater than the fiber density of the first fiber layer. The absorbent article according to claim 1, wherein the average distance between the fibers in the second fiber layer is shorter than the average distance between the fibers in the first fiber layer. The absorbent article according to claim 1, wherein the absorbent article further includes: a pair of side sheets located at both ends in the width direction on the skin side of the surface sheet, and the pair of side sheets , the kinetic friction coefficient when wet is lower than the kinetic friction coefficient of the aforementioned surface sheet when wet.