KR102625454B1 - absorbent article - Google Patents

Abstract

The present invention provides an absorbent article comprising a surface sheet that is excellent in feel and is unlikely to cause unpleasant irritation to the wearer's skin. The absorbent article of the present invention has a topsheet (2) comprising a first fiber layer (2a) comprising water-retaining fibers (F ₁ ) and forming the skin-side surface of the topsheet (2); , comprising thermoplastic resin fibers (F ₂ ) and water-retaining fibers (F ₁ ), and forming a surface on the non-skin side of the top sheet 2 adjacent to the non-skin side of the first fiber layer 2a. and a second fibrous layer (2b), wherein the proportion of water-retaining fibers (F 1 ) in the fibers constituting the first fibrous layer ( _2a ) is water-retaining fibers (F ₁ ) in the fibers constituting the second fibrous layer (2b). ), and at least a part of the water-retaining fibers (F ₁ ) included in the first fiber layer 2a are at least a part of the entangled portions (P _E ) of the intertwined portions (P _E ) of the fibers. is covered with a melt (F _2M ) of the thermoplastic resin fiber (F ₂ ).

Description

absorbent article

The present invention relates to absorbent articles such as sanitary pads.

As a surface sheet used in absorbent articles such as sanitary pads, sheets containing water-retaining fibers such as cotton fibers that absorb and retain moisture are known. For example, in Patent Document 1, absorbent article It is a nonwoven fabric that can be used as a surface material, and is composed of bleached cotton fibers (cotton fibers) to which natural fats and oils are attached and thermoplastic staple fibers whose fiber surface is made of an olefinic polymer at least, and the constituent fibers are three-dimensionally entangled with each other. A nonwoven fabric made by doing so is disclosed. It is said that the nonwoven fabric disclosed in this Patent Document 1 can be suitably used even in fields where conventional nonwoven fabrics made of cotton wool fibers have not been used, such as surface materials for absorbent articles.

Japanese Patent Laid-Open No. 2005-139594

However, as in the nonwoven fabric disclosed in Patent Document 1, simply intertwining cotton fibers (water-retaining fibers) and thermoplastic staple fibers (thermoplastic resin fibers) causes irritation to the wearer's groin area and the skin around it (i.e., irritation). When used as a surface sheet of an absorbent article that is in direct contact with the skin in areas that are easily perceived, the thermoplastic resin fibers contained in the nonwoven fabric tend to cause unpleasant irritation such as a stiff or tingling sensation to the wearer's skin, Additionally, during use of the absorbent article, the fibers become untangled or the water-retaining fibers break due to friction with the wearer's skin, causing fluffing of the water-retaining fibers to occur on the skin-side surface of the top sheet. There was a risk that it would cause unpleasant irritation to the wearer's skin.

Therefore, the purpose of the present invention is to provide an absorbent article including a surface sheet that is excellent in feel and is less likely to cause unpleasant irritation to the wearer's skin.

One aspect (mode 1) of the present invention is an absorbent article comprising a surface sheet,

The surface sheet is,

a first fibrous layer comprising water-retaining fibers and forming a skin-side surface of the top sheet;

A second fiber layer comprising thermoplastic resin fibers and water-retaining fibers, and forming a non-skin side surface of the top sheet adjacent to the non-skin side of the first fiber layer,

The proportion of the water-retaining fibers in the fibers constituting the first fibrous layer is greater than the proportion of the water-retaining fibers in the fibers constituting the second fibrous layer,

At least a portion of the water-retaining fibers included in the first fiber layer are the absorbent article in which at least a portion of the intertwined portions of the fibers are covered with a melt of the thermoplastic resin fibers.

In the absorbent article of the present embodiment, the proportion of water-retaining fibers in the first fibrous layer in the top sheet is greater than the proportion of water-retaining fibers in the second fibrous layer, and at least a portion of the thermoplastic resin fibers contained in the second fibrous layer is 1 Since at least some of the interwoven portions of the fibers included in the fiber layer are made of a melt covering the water-retaining fibers, even if the top sheet contains thermoplastic resin fibers, the thermoplastic resin fibers do not adhere to the wearer's skin. It is difficult to touch, making it difficult to give unpleasant stimulation to the wearer, such as a stiff or tingling sensation.

In addition, in the absorbent article of the present embodiment, at least some of the water-retaining fibers included in the first fiber layer are coated with a melt of thermoplastic resin fibers at at least some of the entangled portions of the intertwined portions of the fibers, so that the fibers in the top sheet are intertwined. Because the entanglement becomes difficult to loosen and the water-retaining fibers become difficult to break, fluffing of the water-retaining fibers resulting from loosening of the entanglements or rupture of the water-retaining fibers can be prevented from occurring, thereby eliminating unpleasant irritation caused by fluffing. This can make it difficult to give it to the wearer.

Accordingly, the absorbent article of this embodiment can realize an absorbent article including a surface sheet with excellent feel that is less likely to cause unpleasant irritation to the wearer's skin.

Moreover, in another aspect (mode 2) of the present invention, in the absorbent article of aspect 1, the thermoplastic resin fiber is one strand of thermoplastic resin fiber intertwined with a plurality of strands of the water-retaining fibers, and the one strand Each of the intertwined portions between the thermoplastic resin fiber and the plurality of water-retaining fibers is covered with a melt of the single strand of the thermoplastic resin fiber.

In the absorbent article of this embodiment, each of the intertwined portions of a single strand of thermoplastic resin fiber and a plurality of water-retaining fibers is covered with a melt of a single strand of thermoplastic resin fiber, so that one strand of the plurality of water-retaining fibers is formed. Since they are connected via thermoplastic resin fibers, it is possible to make it more difficult to cause fluffing due to loosening of the above-described entanglement or breakage of water-retaining fibers.

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

In the absorbent article of this embodiment, since the melt of thermoplastic resin fibers is not exposed to the skin-side surface of the first fiber layer, the presence of the melt is difficult to be sensed by the wearer, and a good feel of the surface sheet can be obtained more reliably. there is.

In another aspect (mode 4) of the present invention, in the absorbent article of any of the above aspects 1 to 3, the average fiber length of the water-retaining fibers included in at least the first fiber layer is the average fiber length of the thermoplastic resin fibers. It's shorter than

In the absorbent article of the present embodiment, the average fiber length of the water-retaining fibers included in the first fiber layer is shorter than the average fiber length of the thermoplastic resin fibers included in the second fiber layer, so that one strand of thermoplastic resin fibers included in the second fiber layer Since the number of water-retaining fibers in the first fiber layer in contact increases, the adhesion amount of melted thermoplastic resin fibers per strand of water-retaining fibers can be increased, making it more difficult to cause fluffing of the water-retaining fibers described above.

In another aspect (mode 5) of the present invention, in the absorbent article of any of the above aspects 1 to 4, the average fiber length of the water-retaining fibers included in at least the first fiber layer is 5 mm or more and less than 35 mm.

In the absorbent article of the present embodiment, since the average fiber length of the water-retaining fibers included in the first fiber layer is within the above-mentioned specific range, fluffing of the water-retaining fibers as described above is unlikely to occur, and the flexibility and texture of the water-retaining fibers are easily maintained. , As a result, the feel of the surface sheet can be improved.

In another aspect (mode 6) of the present invention, in the absorbent article of any of the above aspects 1 to 5, the thermoplastic resin fiber is a composite fiber, and the composite fiber has a resin component with a low melting point on the surface of the composite fiber. is exposed to

In the absorbent article of this embodiment, since the thermoplastic resin fiber is a composite fiber, a resin component with a low melting point exposed to the surface of the fiber (for example, in the case of a core-sheath type composite fiber, forming the sheath) The resin component (or, in the case of side-by-side type composite fibers, the resin component on one side) melts and covers the water-retaining fiber, while the resin component with a high melting point (for example, in the case of core-sheath type composite fibers, the resin that constitutes the core portion) melts and covers the water-retaining fiber. component (or, in the case of side-by-side composite fibers, the resin component on the other side) can remain entangled with water-retaining fibers or other composite fibers, and thus can maintain a predetermined volume as a top sheet.

As a result, the absorbent article of this embodiment makes it difficult for the above-mentioned water-retaining fibers to fluff up, while making it easy for the top sheet to secure good flexibility, texture, cushioning properties, etc.

In another aspect (mode 7) of the present invention, in the absorbent article of any of the above aspects 1 to 6, the top sheet has a pressing portion that is recessed in the thickness direction from the surface on the skin side.

In the absorbent article of this embodiment, since the top sheet has a compression portion formed by embossing or the like, the compression portion holds the water-retaining fibers, making it more difficult for the above-mentioned water-retaining fibers to fluff.

In another aspect (mode 8) of the present invention, in the absorbent article of any of the above aspects 1 to 7, the top sheet extends along the longitudinal direction of the absorbent article and further extends in the width direction of the absorbent article. It has a plurality of convex portions positioned at intervals, and a plurality of concave portions extending along the longitudinal direction of the absorbent article and positioned between adjacent convex portions.

In the absorbent article of this embodiment, the surface sheet has the above-mentioned specific uneven structure, so that the contact area between the surface on the skin side of the surface sheet and the wearer's skin is small, and therefore the thermoplastic resin fibers contained in the surface sheet The possibility of imparting unpleasant irritation to the wearer's skin due to fluffing of water-retaining fibers can be further reduced.

In another aspect (mode 9) of the present invention, in the absorbent article of mode 8, the absorbent article further includes an auxiliary sheet positioned on a non-skin side of the top sheet, and the top sheet includes the above Each of the plurality of recesses is joined to the auxiliary sheet.

In the absorbent article of this embodiment, since the top sheet is joined to the auxiliary sheet in each of the plurality of recesses, the joint with the auxiliary sheet holds the water-retaining fibers, making it more difficult to cause fluffing of the water-retaining fibers as described above. there is.

In another aspect (mode 10) of the present invention, in the absorbent article of any of aspects 1 to 9, the water-retaining fiber is organic cotton.

In the absorbent article of this embodiment, since the water-retaining fiber is organic cotton with excellent flexibility and texture, it is easy for the top sheet to secure good flexibility and texture, and a better feel can be realized.

Additionally, if the top sheet contains such organic cotton, there is also an advantage that the wearer of the absorbent article can be given a sense of security by using a natural material for the top sheet.

In another aspect (mode 11) of the present invention, in the absorbent article of any of aspects 1 to 10, the fiber density of the second fiber layer is greater than the fiber density of the first fiber layer.

In the absorbent article of the present embodiment, the fiber density of the second fiber layer is greater than the fiber density of the first fiber layer, so that the fibers constituting the second fiber layer are close to each other, and the capillary phenomenon occurs more strongly in the second fiber layer. Therefore, the liquid excretion excreted on the skin-side surface of the top sheet (i.e., the skin-side surface of the first fiber layer) can be quickly drawn into the second fiber layer, and the liquid excretion drawn into the second fiber layer can be can be quickly transferred to the non-skin side of the second fiber layer using the thermoplastic resin fibers.

As a result, the absorbent article of this embodiment can secure good absorbent performance while making the surface sheet excellent in texture.

In another aspect (mode 12) of the present invention, in the absorbent article of any of aspects 1 to 11, 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.

In the absorbent article of the present embodiment, 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, so that the fibers constituting the second fiber layer are close to each other, thereby preventing capillary action in the second fiber layer. Since it can be generated more strongly, the liquid excretion excreted on the skin-side surface of the first fiber layer can be quickly drawn into the second fiber layer, and the liquid excretion drawn into the second fiber layer can be absorbed by the thermoplastic resin fibers. It can be quickly transferred to the non-skin side of the second fibrous layer.

As a result, the absorbent article of this embodiment can secure good absorbent performance while making the surface sheet excellent in texture.

In another aspect (mode 13) of the present invention, in the absorbent article of any of the above aspects 1 to 12, the absorbent article has a pair of sides located on the skin side of the top sheet at both ends in the width direction. It further includes a sheet, wherein the pair of side sheets have a coefficient of dynamic friction when wet, which is lower than that of the top sheet when wet.

The absorbent article of this embodiment can provide a smoother feel as an absorbent article because the pair of side sheets that easily come into contact with the skin around the wearer's legs have a lower coefficient of dynamic friction than the surface sheet, which has excellent feel.

According to the present invention, it is possible to provide an absorbent article including a surface sheet with an excellent feel that is less likely to cause unpleasant irritation to the wearer's skin.

Fig. 1 is a plan view of the sanitary pad 1 according to one embodiment of the present invention, viewed in the thickness direction T from the topsheet 2 side in the unfolded state.
FIG. 2 is a cross-sectional view taken along line II-II of the sanitary pad 1 in FIG. 1.
Fig. 3 is an enlarged schematic diagram of the main portion of the first fibrous layer 2a in the topsheet 2.
FIG. 4(a) is an enlarged plan view of the topsheet 2, and FIG. 4(b) is a cross-sectional view taken along line IVb-IVb of the topsheet 2 in FIG. 4(a).
Figure 5 is an electron micrograph of the first fibrous layer in the top sheet of Example 1 of the present invention.
Figure 6 is a comparative photograph showing the occurrence of fluffing between Example 1 of the present invention and Comparative Examples 1 and 2.

Hereinafter, preferred embodiments of the absorbent article of the present invention will be described in detail with reference to the drawings. Additionally, in this specification, unless otherwise specified, “an object (for example, a sanitary pad (absorbent article), etc.) placed on a horizontal surface in an unfolded state is placed in the direction of the thickness of the object from the upper side in the vertical direction. “Seeing” is simply called “flat vision.”

FIG. 1 is a plan view of the sanitary pad 1 according to one embodiment of the present invention as seen in the thickness direction T from the topsheet 2 side in the unfolded state, and FIG. 2 is a view of the sanitary pad 1 according to one embodiment of the present invention in the unfolded state. This is a cross-sectional view taken along line II-II of the sanitary pad (1).

As shown in FIGS. 1 and 2, the sanitary pad 1 of this embodiment has a longitudinal direction (L), a width direction (W), and a thickness direction (T) that are orthogonal to each other, and also has a width direction (T) that is orthogonal to each other. A longitudinal center line (C _L ) (imaginary line) that passes through the center of (W) and extends in the longitudinal direction (L), and a width direction center line that passes through the center of the longitudinal direction (L) and extends in the width direction (W). It has (C _W ) (imaginary line).

In addition, in this specification, in the longitudinal direction L of the sanitary pad 1, the proximal side relative to the width direction center line C _W is referred to as the inner side in the longitudinal direction L. , The distal side relative to the width direction center line (C _W ) is called the outer side in the longitudinal direction (L). Similarly, in the width direction W of the sanitary pad 1, the side relatively proximal to the longitudinal center line C _L is called the inner side in the width direction W, and the side relatively proximal to the longitudinal center line C _L is called the inner side in the width direction W. The relatively distal side is called the outer side in the width direction (W).

In addition, in this specification, an arbitrary direction in a plane including the longitudinal direction (L) and the width direction (W) is referred to as a "plane direction."

In addition, in this specification, in the thickness direction T of the sanitary pad 1, when the sanitary pad 1 is worn, the side relatively proximal to the wearer's skin surface is referred to as the skin side, and the sanitary pad 1 is referred to as the skin side. When wearing the pad 1, the distal side relative to the wearer's skin surface is called the non-skin side.

In addition, this definition of the term is similarly used for various members constituting the sanitary pad 1 and absorbent articles other than the sanitary pad 1.

[Menstrual pad]

As shown in Fig. 1, the sanitary pad 1 according to one embodiment of the present invention (which is an example of an “absorbent article” in the present invention) is long and wide in the longitudinal direction (L) in plan view. It has a substantially rectangular shape that is short in the direction (W), and has a vertically long shape in which both ends in the longitudinal direction (L) protrude to form an arc toward the outer side of the longitudinal direction (L).

In addition, in the central portion of the sanitary pad 1 in the longitudinal direction (L), both ends of the sanitary pad 1 in the width direction (W) face the outer side in the width direction (W). It has a pair of wing portions 9, 9 that protrude toward each other to form a roughly trapezoidal shape.

In addition, the planar shape of the sanitary pad 1 is not limited to this aspect, and as long as it is a vertically elongated shape in which the length in the longitudinal direction (L) is longer than the length in the width direction (W), it can be used in various usage modes, etc. Any shape (for example, rectangular, oval, hourglass, etc.) can be adopted. Additionally, 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 or a semielliptical shape.

As shown in Fig. 2, the sanitary pad 1 of the present embodiment includes a surface sheet 2 that forms the skin-side surface of the sanitary pad 1 in the thickness direction T, and a sanitary pad. The basic structure includes a back sheet 3 forming the non-skin side surface of the pad 1 and an absorber 4 disposed between both sheets.

In addition, in this embodiment, the sanitary pad 1 is an auxiliary sheet disposed between the topsheet 2 and the absorber 4 in the thickness direction T, as shown in FIGS. 1 and 2. (5) and a pair of side sheets (6, 6) disposed at both ends of the sanitary pad (1) in the width direction (W).

In addition, in the present embodiment, each of the pair of side sheets 6, 6 is a pair of loop portions in which both ends of the auxiliary sheet 5 in the width direction W are folded back toward the non-skin side. The skin-side surface of the inner end portion in the width direction W of each side sheet 6 is joined to the non-skin side surface of (5L, 5L) so as to overlap, while the width of each side sheet 6 is The non-skin surface on the outer side in the direction W is joined to the skin-side surface of the back sheet 3.

Hereinafter, various members constituting the sanitary pad 1 of this embodiment will be described in more detail.

Here, FIG. 3 is an enlarged schematic diagram of the main portion of the first fibrous layer 2a in the topsheet 2, FIG. 4(a) is an enlarged plan view of the topsheet 2, and FIG. 4(b) is an enlarged plan view of the topsheet 2. ) is a cross-sectional view taken along line IVb-IVb of the topsheet 2 in Fig. 4(a).

[Surface sheet]

As shown in FIG. 1, the topsheet 2 is extended in the longitudinal direction (L) from the front longitudinal end of the sanitary pad 1 to the rear longitudinal end of the sanitary pad 1 in plan view. ), has a roughly rectangular, vertically elongated shape in plan view. As shown in FIG. 2, the top sheet 2 is disposed at a position on the skin side in the thickness direction T of the sanitary pad 1, and is a contact surface that can come into contact with the wearer's skin (i.e., a sanitary pad). It is composed of a liquid-permeable sheet-like member that forms the skin-side surface of the pad 1.

In addition, in this specification, in the longitudinal direction (L) of the sanitary pad 1, one side that is relatively proximal to the wearer's abdomen when the sanitary pad 1 is worn is referred to as the front side, The other side, which is relatively distal to the wearer's abdomen, is called the posterior side. In this regard, as shown in Fig. 1, the sanitary pad 1 has an anterior region (A _F ), a central region ( _AC ), and a posterior region ( _AB ) in the longitudinal direction (L). has

In this embodiment, the topsheet 2 includes a first fibrous layer 2a containing water-retaining fibers F ₁ and forming the skin-side surface of the topsheet 2, and thermoplastic resin fibers ( F ₂ ) and a second fiber layer ( _2b ) comprising water-retaining fibers (F 1 ) and forming a surface on the non-skin side of the topsheet (2) adjacent to the non-skin side of the first fibrous layer (2a). It is composed of sheet-like members with a two-layer structure.

Additionally, the top sheet 2 may further include one or more fibrous layers on the non-skin side of the second fibrous layer 2b, and may have a multi-layered structure of three or more layers as a whole.

(First fiber layer)

As described above, the first fibrous layer 2a contains water-retaining fibers F ₁ .

The water-retaining fiber (F ₁ ) is not particularly limited as long as it is a fiber that has the property of absorbing and retaining moisture (water-retaining property), and examples include cellulose fibers and the like.

In addition, the cellulose-based fiber is not particularly limited as long as it is a fiber containing cellulose, and examples include natural cellulose fiber, regenerated cellulose fiber, purified cellulose fiber, and semi-synthetic cellulose fiber. Natural cellulose fibers include plant fibers, such as seed hair fibers such as cotton, bast fibers such as hemp, leaf vein fibers such as Manila hemp, and fruit fibers such as palm. .

Moreover, as cotton (fiber), for example, Hirsutum species cotton such as Upland cotton, Barbadense species cotton, Arboreum species cotton, Herbacheum species cotton, etc. Additionally, as cotton (fiber), organic cotton, pre-organic cotton (trademark), etc. can be used. However, organic cotton refers to cotton certified by GOTS (Global Organic Textile Standard).

Examples of regenerated cellulose fibers include rayon, for example, viscose rayon obtained from viscose, polynosic, modal, and copper ammonia rayon (also called "cupra") obtained from a solution of cupra ammonium salt of cellulose. .

As purified cellulose fiber, lyocell, specifically, pulp, is dissolved in an aqueous solution of N-methylmorpholine N-oxide to make a spinning stock solution (dope), and then dissolved in a diluted solution of N-methylmorpholine N-oxide. Examples include those made into fibers by extrusion. In addition, purified cellulose is commercially available as Tencel (trademark), for example.

Examples of semi-synthetic cellulose fibers include acetate fibers such as triacetate and diacetate.

Among the various water-retaining fibers described above, from the viewpoint of water-holding properties and feel, the water-retaining fiber (F ₁ ) is preferably natural cellulose fiber, more preferably cotton, and even more preferably organic cotton.

If the water-retaining fiber (F ₁ ) is organic cotton with excellent flexibility and texture, it is easy for the top sheet 2 to secure good flexibility and texture, and a better feel can be realized. In addition, if the top sheet 2 contains such organic cotton, there is also an advantage that the wearer of the sanitary pad 1 can feel a sense of security by using a natural material for the top sheet 2. .

(second fiber layer)

As described above, the second fiber layer 2b contains thermoplastic resin fibers (F ₂ ) and water-retaining fibers (F ₁ ).

The thermoplastic resin fiber (F ₂ ) is not particularly limited as long as it is a fiber made of a thermoplastic resin (generally a hydrophobic fiber). Thermoplastic resins forming thermoplastic resin fibers (F ₂ ) include, for example, olefin resins such as polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), and polyethylene terephthalate. Known resins include polyester resins such as phthalate (PET) and polylactic acid (PLA), and polyamide resins such as 6-nylon. These resins may be used alone or two or more types of resins may be used in combination. You can do it.

In addition, the structure of the thermoplastic resin fiber (F ₂ ) is not particularly limited and includes, for example, core-sheath type composite fibers such as PET (core)/PE (sheath) or PP (core)/PE (sheath), side-by-side Composite fibers such as side-type composite fibers and island-type composite fibers; hollow type fiber; Fibers with irregular cross-sections such as flat, Y-shaped, and C-shaped; Three-dimensional crimping fibers of latent crimping or current crimping; Examples include split fibers that are divided by physical loads such as water flow, heat, and embossing. Fibers having this structure may be used alone or two or more types of fibers may be used in combination.

In addition, in the sanitary pad 1 of this embodiment, the thermoplastic resin fibers (F ₂ ) of the second fiber layer 2b are core-sheath type composite fibers of PP (core)/PE (sheath).

In addition, the water-retaining fibers (F ₁ ) contained in the second fiber layer 2b are the same as those of the water-retaining fibers (F ₁ ) in the first fiber layer 2a.

And, in the first fibrous layer 2a and the second fibrous layer 2b constituting the topsheet 2, the ratio of water-retaining fibers (F ₁ ) in the fibers constituting the first fibrous layer 2a is It is greater than the ratio of water-retaining fibers (F ₁ ) among the fibers constituting (2b). As a result, even if the top sheet 2 contains thermoplastic resin fibers (F ₂ ), it is difficult for the thermoplastic resin fibers (F ₂ ) to come into contact with the wearer's skin, causing unpleasant irritation such as a stiff or tingling sensation to the wearer. It can be difficult to give it to someone.

In addition, the proportion of water-retaining fibers (F 1 ) among the fibers constituting the first fibrous layer _2a is determined by adjusting the ratio of all constituent fibers of the first fibrous layer 2a (thermoplastic resin to be described later) from the viewpoint of enhancing the feel of the top sheet 2. With respect to the total mass of the fibers (excluding the melt of F ₂ ), 70 mass% to 100 mass% is preferable, 80 mass% to 100 mass% is more preferable, and 90 mass% to 100 mass% is even more preferable. desirable. By setting the proportion of the water-retaining fibers (F ₁ ) to 70% by mass or more, the wearer will feel that the surface on the skin side of the top sheet 2 formed by the first fiber layer 2a contains the water-retaining fibers (F ₁ ). It becomes easier to recognize, and it becomes easier to realize that it feels good to touch.

Furthermore, among the fibers constituting the first fibrous layer 2a, the fibers other than the water-retaining fibers (F ₁ ) are not particularly limited as long as they are fibers capable of forming a liquid-permeable layer, for example, the second fibrous layer 2b. It may contain thermoplastic resin fibers similar to the thermoplastic resin fibers (F ₂ ) contained in .

In this embodiment, the first fibrous layer 2a has a proportion of water-retaining fibers (F ₁ ) of 100% by mass and does not contain fibers other than the water-retaining fibers (F ₁ ).

Moreover, in this embodiment, the average fiber length of the water-retaining fibers (F ₁ ) of the second fiber layer 2b is shorter than the average fiber length of the water-retaining fibers (F ₁ ) of the first fiber layer 2a. As a result, at least the fibers constituting the second fibrous layer 2b are likely to approach each other (that is, the distance between the fibers is likely to be shortened), and capillary action is more likely to occur, thereby preventing liquid excretions such as menstrual blood or urine. It can be drawn more strongly into the second fiber layer (2b).

As shown in FIG. 3, at least some of the water-retaining fibers (F ₁ ) included in the first fibrous layer 2a are thermoplastic in at least some of the entangled portions (P _E ) of the intertwined portions (P _E ) of the fibers. It is covered with a melt (F _2M ) of resin fibers (F ₂ ).

In this way, in the sanitary pad 1 of the present embodiment, the ratio of the water-retaining fibers (F 1 ) of the first fibrous layer 2a in the topsheet 2 is the water-retaining fibers (F ₁ ) of the second fibrous layer 2b. ₁ ), and at least a part of the thermoplastic resin fibers (F ₂ ) contained in the second fiber layer 2b are intertwined portions (P _E ) of the fibers contained in the first fiber layer 2a. Since at least some of the entangled portions (P _E ) are made of melt (F _2M ) covering the water-retaining fibers (F ₁ ), even if the top sheet 2 includes thermoplastic resin fibers (F ₂ ), It is difficult for the thermoplastic resin fibers (F ₂ ) to come into contact with the wearer's skin, making it difficult to give the wearer unpleasant stimulation such as a stiff or tingling touch.

In addition, in the sanitary pad 1 of the present embodiment, at least some of the water-retaining fibers (F 1 ) included in the first fibrous layer _2a are entangled at least in part (P _E ) among the intertwined portions (P E ) of the fibers. In _E ), by being covered with a melt (F _2M ) of thermoplastic resin fibers (F ₂ ), the fibers in the top sheet 2 are made difficult to become entangled with each other, and at the same time, the water-retaining fibers (F ₁ ) are made difficult to break. Because of this, fluffing of the water-retaining fibers (F ₁ ) due to loosening of the entanglement or breakage of the water-retaining fibers (F ₁ ) can be prevented from occurring, and it can be difficult to cause unpleasant irritation to the wearer due to the fluffing. .

Accordingly, the sanitary pad 1 of the present embodiment includes a surface sheet 2 that is excellent in feel and is unlikely to cause unpleasant irritation to the wearer's skin.

In addition, in this specification, the interwoven portion refers to the portion where fibers are intertwined, and is a portion including the interwoven point and the surrounding area of the interwoven point.

In addition, in this specification, melt means a state that has solidified through a molten state.

In addition, 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 2b of the topsheet 2. As a result, the top sheet 2 has a sheath portion of the core-sheath type composite fiber made of a resin component with a low melting point melted to cover the water-retaining fibers (F ₁ ), while the core portion made of a resin with a high melting point melts the water-retaining fibers (F ₁ ) or other core-sheath type composite fibers (thermoplastic resin fibers (F ₂ )) can be maintained in an entangled state, and a predetermined volume can be maintained as a top sheet.

Additionally, when a thermoplastic resin fiber, such as a side-by-side type composite fiber, is used in which a resin component with a low melting point is exposed on the surface of the composite fiber, the same effect as above can be exhibited.

In addition, in the present embodiment, the above-mentioned thermoplastic resin fiber (F ₂ ) has one strand of thermoplastic resin fiber (F ₂ ) intertwined with multiple strands of water-retaining fibers (F ₁ ), and the one strand of Each of the intertwined portions (P _E ) between the thermoplastic resin fiber (F ₂ ) and the plurality of water-retaining fibers (F ₁ ) is covered with a melt (F _2M ) of the single strand of thermoplastic resin fiber (F ₂ ). there is.

In this way, each of the entangled portions (P _E ) of the single-stranded thermoplastic resin fiber (F ₂ ) and the plurality of water-retaining fibers (F ₁ ) is a melt (F _2M ) of the single-stranded thermoplastic resin fiber (F ₂ ). When covered with , multiple strands of water-retaining fibers (F ₁ ) are connected via one strand of thermoplastic resin fiber (F ₂ ), so that the loosening of the above-mentioned entanglement or breakage of the water-retaining fibers (F ₁ ) causes This can make it more difficult for fluff to form.

Moreover, in the present invention, it is preferable that the melt of the thermoplastic resin fiber is not exposed to the skin-side surface of the first fiber layer. If the melt of the thermoplastic resin fibers is not exposed to the skin-side surface of the first fiber layer, the presence of the melt is less likely to be detected by the wearer, and a good feel of the surface sheet can be more reliably obtained.

The fiber length (average fiber length) of the water-retaining fibers (F ₁ ) of the first fiber layer 2a is not particularly limited as long as it does not impair the effect of the present invention, but at least the water-retaining fibers contained in the first fiber layer 2a ( It is preferable that the average fiber length of F ₁ ) is shorter than the average fiber length of thermoplastic resin fibers (F ₂ ). If the average fiber length of the water-retaining fibers (F ₁ ) included in the first fiber layer (2a) is shorter than the average fiber length of the thermoplastic resin fibers (F ₂ ) included in the second fiber layer (2b), Since the number of water-retaining fibers (F ₁ ) of the first fiber layer 2a in contact with one strand of thermoplastic resin fibers (F ₂ ) contained increases, the melt (F) of the thermoplastic resin fibers (F ₂ ) per strand of the water-retaining fibers is increased. The amount of adhesion of _2M ) can be increased, and fluffing of the water-retaining fiber (F ₁ ) described above can be made more difficult to occur.

In addition, the specific average fiber length of the water-retaining fibers (F ₁ ) contained in the first fiber layer 2a includes, for example, an average fiber length of 5 mm to 80 mm (that is, 5 mm or more and 80 mm or less). When the average fiber length of the water-retaining fibers (F ₁ ) is 5 mm or more, the flexibility and texture of the water-retaining fibers (F ₁ ) are easily maintained, and the fibers become easily entangled with each other, making it easy to obtain sufficient strength. On the other hand, if the average fiber length of the water-retaining fibers (F ₁ ) is 80 mm or less, it becomes difficult for some of the water-retaining fibers (F ₁ ) to extend outward in the width direction (W) of the sanitary pad 1. It is possible to make it difficult for liquid excrement to leak out from the width direction (W) of the sanitary pad (1) along the water-retaining fibers (F ₁ ) extending outward in the width direction (W).

In addition, the average fiber length of the water-retaining fibers (F ₁ ) contained in the first fiber layer 2a is preferably 5 mm or more and 60 mm or less, and more preferably 5 mm or more and less than 35 mm. If the average fiber length of the water-retaining fibers (F ₁ ) contained in the first fiber layer 2a is 5 mm or more and less than 35 mm, fluffing of the water-retaining fibers (F ₁ ) described above is unlikely to occur, and the flexibility of the water-retaining fibers (F ₁ ) is maintained. It is easy to maintain the texture, and as a result, the feel of the top sheet 2 can be improved.

In addition, the fineness, average fiber length, etc. of fibers other than the water-retaining fibers (F ₁ ) in the first fiber layer 2a are not particularly limited, but the effect on the texture of the water-retaining fibers (F ₁ ) Considering the above, it is preferable that it is the same as the water-retaining fiber (F ₁ ) (within the range of 0.5 to 2 times). However, in this embodiment, as described above, the first fibrous layer 2a does not contain fibers other than the water-retaining fibers (F ₁ ).

The proportion of water-retaining fibers (F ₁ ) in the fibers constituting the second fibrous layer 2b is not particularly limited as long as it is less than the proportion of water-retaining fibers (F ₁ ) in the first fibrous layer 2a. The ratio of the water-retaining fibers (F ₁ ) of the second fibrous layer 2b is, for example, 50 to 90 mass% with respect to the total mass of all constituent fibers of the second fibrous layer 2b. If the proportion of water-retaining fibers (F ₁ ) is 50% by mass or more, the touch feeling when pressure is applied in the thickness direction (T) can be good, and if the proportion of water-retaining fibers (F ₁ ) is 90% by mass or less. , the effect of preventing fluffing caused by the melt (F _{2 M} ) of the thermoplastic resin fiber (F ₂ ) is exhibited more stably.

Additionally, the ratio of the water-retaining fibers (F ₁ ) in the second fibrous layer 2b is preferably 60% by mass to 85% by mass, and more preferably 70% by mass to 80% by mass. Correspondingly, the proportion of thermoplastic resin fibers (F ₂ ) in the second fiber layer 2b is, for example, 10% by mass to 50% by mass with respect to the total mass of all constituent fibers of the second fiber layer 2b. can be mentioned, and 15 mass% to 40 mass% is preferable, and 20 mass% to 30 mass% is more preferable.

In addition, the second fiber layer 2b may contain third fibers in addition to the water-retaining fibers (F ₁ ) and thermoplastic resin fibers (F ₂ ).

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

The fiber length (average fiber length) of the water-retaining fibers (F ₁ ) of the second fibrous layer (2b) is not particularly limited as long as it does not impair the effect of the present invention, but, like the above-described first fibrous layer (2a), a thermoplastic resin It is preferable that it is shorter than the average fiber length of the fiber (F ₂ ). If the average fiber length of the water-retaining fibers (F ₁ ) is shorter than the average fiber length of the thermoplastic resin fibers (F ₂ ), the number of water-retaining fibers (F ₁ ) in contact with one strand of thermoplastic resin fibers (F ₂ ) increases. The amount of adhesion of the melt (F _2M ) of the thermoplastic resin fibers (F ₂ ) per strand of water-retaining fiber can be increased, making it more difficult to cause loosening of the entanglements between the above-mentioned fibers and fracture of the water-retaining fiber (F ₁ ). .

In addition, a specific average fiber length of the water-retaining fibers (F ₁ ) contained in the second fiber layer 2b includes, for example, an average fiber length of 3 mm to 40 mm. If the average fiber length of the water-retaining fibers (F ₁ ) is 3 mm or more, it is easy to maintain the flexibility and texture of the water-retaining fibers (F ₁ ) and the fibers become easily entangled with each other, making it easy to obtain sufficient strength. On the other hand, if the average fiber length of the water-retaining fibers (F ₁ ) is 40 mm or less, the dynamic freedom of the web-like fibers is high during production of the second fiber layer 2b, and the water-retaining fibers (F ₁ ) are thermoplastic resin fibers (F ₂ ). Since it becomes easy to enter the gap between the fibers, the distance between the fibers in the second fiber layer 2b tends to shorten, and as a result, the fiber density of the second fiber layer 2b tends to increase.

In addition, the average fiber length of the water-retaining fibers (F ₁ ) included in the second fiber layer 2b is not particularly limited, as is the case with the water-retaining fibers (F ₁ ) of the above-described first fiber layer 2a, but is 5 mm or more and 35 mm. It is preferable to be less than If the average fiber length of the water-retaining fibers (F ₁ ) included in the second fiber layer 2b is within this range, it is easy to maintain the flexibility and texture of the water-retaining fibers (F ₁ ), and as a result, the surface sheet 2 The texture can be improved.

In addition, in the present invention, as water-retaining fibers (F ₁ ) contained in at least the second fiber layer 2b, mixed water-retaining fibers in which two or more types of water-retaining fibers with different average fiber lengths are mixed can be used. For example, water-retaining fibers are water-retaining fibers with a long average fiber length, and water-retaining fibers with an average fiber length of 15 mm to 40 mm (preferably 20 mm to 35 mm), and water-retaining fibers with a short average fiber length, with an average fiber length of Water-retaining fibers with a thickness of 3 mm to 25 mm (preferably, 5 mm to 20 mm) can be mixed and used. When such mixed water-retaining fibers are used as the water-retaining fibers (F ₁ ) of the second fiber layer 2b, the water-holding properties and texture of the second fiber layer 2b are improved by the water-retaining fibers having a long average fiber length, while the average fiber length is increased. The distance between fibers of the second fiber layer 2b can be shortened by using short water-retaining fibers.

In addition, when the second fibrous layer 2b includes one or more fibrous layers on the non-skin side, that is, when the top sheet 2 has a multilayer structure of three or more layers as a whole, liquid permeability is reduced. From the viewpoint of higher height, the closer the fiber layer is to the non-skin side surface of the topsheet 2, the relatively lower the proportion of water-retaining fibers (F ₁ ), and the shorter the average fiber length of the water-retaining fibers (F ₁ ) is. do.

Ease of entanglement of the thermoplastic resin fibers (F 2 ) of the second fiber layer ( _2b ) and the water-retaining fibers (F ₁ ), which are the main constituent fibers of the first fiber layer (2a), that is, from the first fiber layer (2a) From the viewpoint of ease of transfer of liquid excrement and preventing delamination between the first fiber layer 2a and the second fiber layer 2b, the fineness of the thermoplastic resin fibers F ₂ of the second fiber layer 2b is, It is preferable that the fineness is smaller than that of the water-retaining fibers (F ₁ ) of the first fiber layer (2a).

In addition, the fiber length (average fiber length) of the thermoplastic resin fibers (F ₂ ) of the second fiber layer 2b is not particularly limited as long as it does not impair the effect of the present invention, and examples include 10 mm to 80 mm. there is. However, the ease with which the thermoplastic resin fibers (F 2 ) of the second fiber layer ( _2b ) and the water-retaining fibers (F ₁ ), which are the main constituent fibers of the first fiber layer (2a), are entangled with each other, that is, the liquid phase from the first fiber layer (2a). From the viewpoint of ease of movement of excrement and prevention of delamination between the first fiber layer 2a and the second fiber layer 2b, the average fiber length of the thermoplastic resin fibers F ₂ of the second fiber layer 2b is, It is preferable that the average fiber length is longer than the average fiber length of the water-retaining fibers (F ₁ ) of the first fiber layer (2a) and the second fiber layer (2b), for example, an average fiber length of 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 impair the effect of the present invention, and examples include a thickness of 0.05 mm to 4 mm, and a thickness of 0.1 mm. A thickness of ~3 mm is preferred, and a thickness of 0.2 mm~2 mm is more preferred.

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 feel of the first fiber layer 2a is improved and rewetting to the wearer's skin is improved. It becomes easy to suppress bagging, and when the thickness of the first fiber layer 2a is relatively thin and the thickness of the second fiber layer 2b is relatively thick, the water-retaining fibers (F ₁ ) of the first fiber layer 2a Since the second fiber layer 2b is easily covered by the melt ( _F2M ) of the thermoplastic resin fibers ( _F2 ), fluffing caused by the above-mentioned water-retaining fibers ( _F1 ) can be more reliably suppressed. .

Additionally, the thickness of the top sheet 2 (i.e., the total thickness of each fibrous layer) is not particularly limited as long as it does not impair the effect of the present invention, and examples include a thickness of 0.1 mm to 5 mm, and a thickness of 0.4 mm. A thickness of mm to 4 mm is preferable, and a thickness of 0.8 mm to 3 mm is more preferable.

Here, the ratio of fiber types in a sheet such as a fiber layer can be measured as follows.

That is, the ratio of fiber types can be measured by coloring water-retaining fibers and thermoplastic resin fibers in different colors according to the following procedure.

(1) The top sheet (2) is cut to a size of 70 mm x 70 mm to serve as a sample.

(2) By performing a coloring treatment with the reagent KayastainQ (manufactured by Shikisensha Co., Ltd.), only the water-retaining fibers are dyed blue and only the thermoplastic resin fibers are colored yellow.

(3) Using a digital microscope VHX-100 manufactured by Keyence Co., Ltd., the ratio of blue to yellow as seen from the surface of the skin side of the sample (first fiber layer 2a) is measured in a range of 50 mm x 50 mm. , is the ratio of fiber types in the first fiber layer 2a. On the other hand, the ratio of blue and yellow when viewed from the surface on the non-skin side (second fiber layer 2b) is measured in the range of 50 mm x 50 mm, and is taken as the ratio of fiber types in the second fiber layer 2b. .

In addition, in judging the magnitude relationship of the ratio of fiber types, if the magnitude relationship between the ratios of blue and yellow is clear by appearance, it can be judged by the appearance, but the magnitude relationship between the ratios of blue and yellow is only apparent. If it is not possible to determine, count the number of strands of fiber colored in each color and calculate It can be judged by calculating the total mass of the fibers and comparing the total masses.

Additionally, the distance between constituent fibers in a sheet such as a fibrous layer can be measured according to the following measurement method.

(1) The top sheet (2) is cut to a size of 10 mm x 10 mm to serve as a sample.

(2) Using a digital microscope VHX-100 manufactured by Keyence Corporation (lens VH-Z20R + variable illumination attachment VH-K20), photographing magnification: 200 times, measurement area: 1300 ㎛ vertical x 1735 ㎛ wide, the surface Each image of the skin-side surface (first fibrous layer 2a) and the non-skin-side surface (second fibrous layer 2b) of the sheet 2 is taken. At that time, images are taken for each of the skin-side surface and the non-skin-side surface in a depth range of 0 μm to 100 μm, a total of 5 times for every 20 μm in depth.

(3) From each obtained image, the area of the area where fibers are not present is calculated. At that time, the presence or absence of fibers in each pixel is determined depending on whether the luminance at each pixel in each obtained image is lower or higher than the predetermined luminance (threshold), and the presence or absence of fibers in the imaging area in each image is determined. do. However, since light only passes through the area where fibers do not exist and becomes brighter (i.e., the luminance increases), this is used to calculate the area of the area where fibers do not exist in the imaging area.

(4) The area of the area where fibers are not found is subtracted from the area of the imaging area (measured area) and further divided by the area of the imaging area (measured area) to calculate the porosity. Such calculations are performed on images every 20 μm in depth, and five porosity values are calculated.

(5) The average value of the five calculated porosity is taken as the respective porosity of the skin-side surface (first fibrous layer 2a) and the non-skin-side surface (second fibrous layer 2b) of the top sheet 2. do. By comparing the size of this porosity, the size of the distance between fibers can be determined. In other words, when the porosity is large, the distance between fibers is large. For example, the skin-side surface of the topsheet 2 (the first fiber layer 2a: for example, the surface of 100% cotton fiber (water-retaining fiber)) has a porosity of 25.4%, and the non-skin-side surface ( The second fiber layer 2b (for example, a surface of 60% cotton fibers (water-retaining fibers) and 40% thermoplastic resin fibers) has a porosity of 24.5%.

In addition, the fiber length (average fiber length) of the fibers of the sheet, such as the fiber layer, is determined by “A7.1.1 Method A (standard method)” of “A7.1 Measurement of fiber length” in Annex A of JIS L 1015:2010, “Graded glass plate.” It can be measured according to “Method for measuring the length of individual fibers.” Additionally, the above method is a test method equivalent to ISO 6989 published in 1981.

Additionally, the basis weight of a sheet such as a fibrous layer can be measured according to the following measurement method. That is, one fiber layer is produced, the fiber layer is cut to a size of 5 cm x 5 cm to make a sample, and the mass of the sample is measured after drying is performed in an atmosphere of 100°C or higher. Next, the measured mass is divided by the area of the sample to calculate the basis weight of the sample. The average of the basis weights of 10 samples is taken as the basis weight of the sheet.

Additionally, the thickness of a sheet such as a fibrous layer can be measured according to the following measurement method. That is, an enlarged image in a direction perpendicular to the cut surface of the top sheet 2 is captured using a digital microscope VHX-100 manufactured by Keyence Corporation. At this time, the enlarged image is an image enlarged at a magnification such that the entire thickness direction T of the top sheet 2 can be imaged, and the magnification is, for example, 20 to 50 times. The obtained enlarged image (3-dimensional image) is converted into a two-dimensional image, and the thickness of each fibrous layer is measured in the two-dimensional image. The average value of the thickness measured at each of the three cut surfaces is taken as the thickness of the top sheet 2.

In addition, in the sanitary pad 1 of the above-described embodiment, it is preferable that the average distance between the constituent fibers of the second fibrous layer 2b is shorter than the average distance between the constituent fibers of the first fibrous layer 2a. If the average distance between the constituent fibers of the second fibrous layer 2b is shorter than the average distance between the constituent fibers of the first fibrous layer 2a, the fibers constituting the second fibrous layer 2b approach each other, and the second fibrous layer (2b) Since the capillary phenomenon can be generated more strongly in 2b), the liquid excretion excreted on the skin-side surface of the first fiber layer 2a can be quickly drawn into the second fiber layer 2b, and further, the second fiber layer 2b The liquid excrement drawn into (2b) can be quickly transferred to the non-skin side of the second fiber layer (2b) by the thermoplastic resin fibers (F ₂ ).

Accordingly, the sanitary pad 1 having this structure can ensure good absorbent performance while providing the top sheet 2 with an excellent feel.

In addition, in the sanitary pad 1 of this embodiment, it is preferable that the fiber density of the second fibrous layer 2b is greater than the fiber density of the first fibrous layer 2a. That is, it is preferable that a gradient in fiber density exists in the thickness direction T of the topsheet 2 so that the fiber density increases from the first fiber layer 2a to the second fiber layer 2b.

In this way, if the fiber density of the second fiber layer 2b is greater than the fiber density of the first fiber layer 2a, the fibers constituting the second fiber layer 2b are close to each other and are in the second fiber layer 2b. Since the capillary phenomenon can be generated more strongly, the liquid excrement supplied to the skin-side surface of the top sheet 2 (i.e., the skin-side surface of the first fiber layer 2a) is transferred to the second fiber layer 2b. It can be pulled in quickly, and the liquid excrement drawn into the second fiber layer 2b can be quickly moved to the non-skin side of the second fiber layer 2b by the thermoplastic resin fibers F ₂ .

Accordingly, the sanitary pad 1 having this structure can ensure good absorbent performance while providing the top sheet 2 with an excellent feel.

However, when one or more fiber layers are additionally provided on the non-skin side surface of the second fiber layer 2b, that is, when the top sheet 2 has a multi-layer structure of three or more layers, the top sheet The closer the fiber layer is to the surface of the non-skin side of (2), the higher the fiber density is preferably. Thereby, liquid permeability from the fibrous layer located relatively on the skin side to the fibrous layer located relatively on the non-skin side can be further increased, and liquid excretions can be stably transferred through the auxiliary sheet 5 and the absorber 4. You can.

Additionally, the fiber density of a sheet such as a fiber layer can be measured according to the following measurement method.

(1) The top sheet (2) is cut to a size of 10 mm x 10 mm to serve as a sample.

(2) The cut surface parallel to the thickness direction (T) of the sample is magnified and observed using a scanning electron microscope (JCM-5100, manufactured by Nippon Electronics Co., Ltd.). The magnification is set at a magnification that allows the cross-section of 30 to 60 strands of fiber to be measured within one stroke (for example, 150 to 500 times).

(3) The observation area is divided into three parts in the thickness direction (T) into a skin-side layer, a middle layer, and a non-skin-side layer, with the skin-side layer being the first fiber layer 2a and the non-skin-side layer being the first fiber layer 2a. After forming the second fiber layer 2b, the number of cross sections of fibers in each fiber layer is measured. That is, in a cut surface of a predetermined area, the number of cross sections of cut fibers is counted.

(4) The number of cross sections of the obtained fiber is converted into the number of cross sections of the fiber per 1 mm2, and this is referred to as the fiber density (strand/mm2). Measurements are performed at three locations, and the average of the measured values is taken as the fiber density of the sample. That is, as the fiber density, the density of the number of fiber strands is used. In other words, as the fiber density, the number of fiber strands per unit area in a cross section parallel to the thickness direction (T) is used.

Additionally, as the fiber density, the number of fiber strands per unit volume may be used. The number of fiber strands per unit volume can be obtained, for example, through analysis using X-ray CT. Although the values of fiber density are different for the fiber density per unit area and the fiber density per unit volume, the relative comparison of fiber densities between fiber layers (for example, comparison of size and size) gives the same result.

Moreover, as shown in FIG. 3, in this embodiment, some of the thermoplastic resin fibers _F2 contained in the second fiber layer 2b are heat-fused to each other. That is, some of the thermoplastic resin fibers (F ₂ ) are bonded to each other by heat fusion at locations where the thermoplastic resin fibers are in contact with each other, and within the second fiber layer 2b, a kind of matrix of thermoplastic resin fibers (F ₂ ) is formed. It can be seen that it is forming.

The sanitary pad 1 having such a configuration stabilizes the shape of the second fibrous layer 2b by some thermoplastic resin fibers F ₂ heat-fused to each other. Therefore, even if the average fiber length of the water-retaining fibers (F ₁ ) included in the second fiber layer 2b is relatively short, the water-retaining fibers (F ₁ ) can be maintained between the thermoplastic resin fibers (F ₂ ) (within the matrix). It can be maintained stably without bias. As a result, the sanitary pad 1 of the present embodiment can stably transfer the liquid excrement drawn into the second fibrous layer 2b to the absorbent body 4 (and the auxiliary sheet 5) without bias, It can demonstrate excellent absorption performance.

Additionally, the thermoplastic resin fibers (F ₂ ) of the sanitary pad 1 do not need to be heat-sealed to each other like this.

Moreover, as shown in FIG. 4, in this embodiment, at least a part of the thermoplastic resin fibers _F2 of the second fiber layer 2b are exposed to the skin-side surface of the first fiber layer 2a. That is, the thermoplastic resin fibers (F ₂ ) of the second fibrous layer (2b) stably maintain the shape of the second fibrous layer (2b), and at least a portion thereof is continuously formed in the first fibrous layer (2a) from the second fibrous layer (2b). ), and further they reach the skin-side surface of the first fiber layer 2a.

In the sanitary pad 1 having such a configuration, the thermoplastic resin fibers F ₂ of the second fiber layer 2b extend continuously to the inside of the first fiber layer 2a, thereby forming the first fiber layer 2a. ) of the water-retaining fibers (F ₁ ) can be stably held between the thermoplastic resin fibers (F ₂ ), the average distance between the constituent fibers of the first fiber layer (2a) is relatively long, and the Even in cases where the strength is relatively weak, collapsing can be prevented. In addition, the water retention fibers (F ₁ ) of the first fiber layer 2a are held between the thermoplastic resin fibers (F ₂ ) and are further covered by the melt (F _2M ) of the thermoplastic resin fibers (F ₂ ), thereby improving the water retention capacity. The occurrence of fluff caused by fracture of the fiber (F ₁ ) can be effectively suppressed.

Accordingly, the sanitary pad 1 having such a structure can provide the first fibrous layer 2a of the top sheet 2 with a superior feel.

In addition, a part of the thermoplastic resin fibers (F ₂ ) that do not have the water retention properties of the second fiber layer (2b) exist in the first fiber layer (2a), thereby forming the first fiber layer (2a) via the thermoplastic resin fibers (F ₂ ). Since the transfer of liquid excrement from the to the second fibrous layer 2b can be promoted, the liquid excrement can be stably transferred to the absorbent body 4 (and the auxiliary sheet 5).

Additionally, the thermoplastic resin fibers (F ₂ ) of the second fibrous layer 2b of the sanitary pad 1 do not need to be exposed to the skin-side surface of the first fibrous layer 2a.

In addition, in this embodiment, the fibers constituting the topsheet 2 are fibers present at both ends in the width direction (W) of the topsheet 2, and The fibers present in the central portion are oriented in the longitudinal direction L of the topsheet 2. That is, in the topsheet 2 of the present embodiment, the fibers present in the central portion in the width direction (W) have a relatively small orientation in the longitudinal direction (L), and the fibers present in both ends in the width direction (W) has a relatively large orientation in the longitudinal direction (L).

In the sanitary pad 1 having such a configuration, the fiber orientation is relatively random in the central portion of the topsheet 2 in the width direction W, so that liquid excretions can be spread in a substantially concentric circle. In addition, since the fiber orientation is formed in the longitudinal direction (L) at both ends in the width direction (W) of the topsheet 2, the liquid excrement that reaches the both ends can be spread in the longitudinal direction (L). In other words, the sanitary pad 1 can be used as a whole in a planar direction, and superior absorption performance can be achieved. In addition, at both ends of the top sheet 2 in the width direction W, the number of fiber strands exposed from the end edges is reduced, so friction against the wearer's skin is reduced and the touch can be made smoother.

Additionally, the fiber orientation of the topsheet 2 of the sanitary pad 1 does not need to be relatively large in the longitudinal direction (L) at both ends in the width direction (W).

As shown in FIG. 1, the sanitary pad 1 has an excretory outlet contact area ( ) is set. The excretory outlet contact area The excretion port contact area /4 to 1/2 in length, approximately 1/2 to 1/3 of the total length in the width direction (W) of the absorber (4), located at approximately the center of the absorber (4) in the width direction (W). It is set to the width of .

In addition, when the absorbent article is provided with a wing portion, such as the above-mentioned sanitary pad 1, the outlet contact area is generally set to overlap the wing part in the width direction, for example, the outlet contact area. can be set so that the longitudinal center position of the excrement abutment area approximately overlaps the longitudinal center position of the wing portion in the width direction.

(Compression part)

In this embodiment, as shown in FIG. 1, the sanitary pad 1 is located on both outer sides in the width direction W with respect to the excretory outlet contact area XA and is continuous or continuous in the longitudinal direction L. It is provided with a pair of intermittently continuous pressing portions (compression grooves) 12, 12.

Additionally, as shown in Fig. 1, in this embodiment, the sanitary pad 1 is located on the rear side of each of the pair of compression portions 12, 12 in the longitudinal direction L, and is positioned in the longitudinal direction L ), a pair of pressing portions (compression grooves) 13, 13 extending in series, and a heart-shaped ring ( It is further provided with compression portions (compression grooves) 11, 14 having a round shape and a plurality of point-shaped compression portions 15 in the excretory port contact area XA.

These pressing portions 11 to 15 are formed by pressing the top sheet 2 and the absorber 4 in the thickness direction T using processing means such as embossing. That is, the top sheet 2, the auxiliary sheet 5, and the absorbent body 4 (specifically, the core wrap 4b and the absorbent core 4a on the skin side of the absorbent body 4) are aligned in the thickness direction T. It is formed by compression. As shown in FIG. 2, each compression portion is weakly compressed and strongly compressed with a low-density portion (LPA) formed at a shallow position from the skin-side surface of the topsheet 2 and having a relatively low fiber density. Thus, the top sheet 2 has a high-density portion (HPA) formed at a deep position from the skin-side surface and having a relatively high fiber density. These low-density portions (LPA) and high-density portions (HPA) may be said to be the bottom portion of each compression portion at a shallow position and the bottom portion of a deep position.

As shown in Fig. 2, the low-density portion (LPA) and the high-density portion (HPA) of the compression portions 11 to 15 are located within the absorbent core 4a, but the high-density portion (HPA) is located in the core wrap on the non-skin side. (4b) may be reached.

Additionally, the shape of the pressing portions 11 to 15 is not particularly limited, and any shape depending on desired liquid diffusivity, deformation induction, strength, etc. can be adopted.

In addition, the sanitary pad 1 does not need to be provided with such pressing portions 11 to 15, but is preferably provided with at least one pressing portion among the pressing portions 11 to 15.

If the sanitary pad 1 (more specifically, the topsheet 2) has a compressed portion that is recessed in the thickness direction (T) from the surface on the skin side, the compressed portion is a water-retaining fiber ( By holding F ₁ ), fluffing of the above-mentioned water-retaining fibers (F ₁ ) can be made more difficult to occur.

In addition, in this embodiment, at least a part of the thermoplastic resin fibers (F ₂ ) of the second fiber layer 2b are attached to the inner surface of the pressing portion in at least one of the pressing portions 11 to 15. It is exposed. When the sanitary pad 1 has such a configuration, the thermoplastic resin fibers F ₂ are present in the first fibrous layer 2a so as to be exposed to the inner surface of the compression portion, so that the first fiber layer 2a is present even within the compression portion. ) of water-retaining fibers (F ₁ ) can be stably held between thermoplastic resin fibers (F ₂ ). As a result, fluffing due to the water-retaining fibers (F ₁ ) can be prevented even within the compression portion, and the feel of the first fiber layer 2a within the compression portion can be improved. In addition, a part of the thermoplastic resin fibers (F ₂ ) that do not have the water retention properties of the second fiber layer (2b) are present in the first fiber layer (2a) in the compression portion, so that the thermoplastic resin fibers (F ₂ ) are interposed within the compression portion. Since the transfer of liquid excrement from the first fibrous layer 2a to the second fibrous layer 2b can be promoted, the liquid excrement can be transferred more stably to the absorbent body 4 (and the auxiliary sheet 5).

Additionally, in the sanitary pad 1, the thermoplastic resin fibers F ₂ do not need to be exposed to the surface inside the compression portion.

In addition, in this embodiment, at least a part of the thermoplastic resin fibers (F ₂ ) of the second fiber layer 2b are in the low-density portion (LPA) of at least one of the compression portions 11 to 15. ) is exposed on the surface. When the sanitary pad 1 has such a configuration, the thermoplastic resin fibers F ₂ are present in the first fiber layer 2a so as to be exposed to the surface of the low-density portion LPA, thereby 1 The water-retaining fibers (F ₁ ) of the fiber layer (2a) can be stably held between the thermoplastic resin fibers (F ₂ ). As a result, it is possible to prevent fluffing caused by the water-retaining fibers (F ₁ ) even in the low-density portion (LPA), and the feel of the first fiber layer 2a in the low-density portion (LPA) can be improved. In addition, a part of the thermoplastic resin fibers (F ₂ ) that do not have the water retention properties of the second fiber layer (2b) exist in the first fiber layer (2a) in the low-density portion (LPA), thereby interposing the thermoplastic resin fibers (F ₂ ). Since the transfer of liquid excrement from the first fibrous layer 2a to the second fibrous layer 2b in the low-density area (LPA) can be promoted, liquid excrement can be transferred to the absorber 4 (and the auxiliary sheet 5) more stably. It can be implemented by .

Additionally, the sanitary pad 1 does not require the thermoplastic resin fibers F ₂ to be exposed to the surface of the low-density portion LPA.

(irregular structure)

In this embodiment, the topsheet 2 has an uneven structure as shown in FIG. 4 .

As shown in Fig. 4(b), the first fibrous layer 2a has a first upper surface 2aE on the upper side (skin side) and a first lower surface 2aF on the lower side (non-skin side) in the thickness direction T. The second fibrous layer 2b has an upper second upper surface 2bE and a lower second lower surface 2bF in the thickness direction T. 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, but some of the fibers of the two fiber layers are different from each other due to entanglement. Because it is contained in the fibrous layer, it is not a strict boundary.

In addition, the first fibrous layer 2a extends continuously along the longitudinal direction L and is arranged at a predetermined interval in the width direction W, and the first upper surface 2aE protrudes upward (to the skin side). The first upper surface 2aE, which is disposed between the plurality of convex portions 21 and the convex portions 21 that extend continuously along the longitudinal direction L and are adjacent to each other, is disposed toward the lower side (non-skin side). It has a plurality of recessed portions 22 that are hollowed out.

If the surface sheet 2 has a specific concavo-convex structure including a plurality of convex portions 21 and a plurality of concave portions 22, the skin-side surface of the top sheet 2 and the wearer's skin Since _the contact area _of can do.

Additionally, 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 portions 21 has a solid structure, it becomes difficult for each convex portion 21 to be crushed, and at the same time, the liquid from each convex portion 21 that easily touches the wearer's body is absorbed into the absorber 4. Since the transferability is excellent, the drying property of the surface of each convex portion 21 can be improved.

On the other hand, the second fibrous layer 2b has a substantially flat structure except for the later-described depressions 23 formed by compression. However, the second upper surface 2bE of the second fibrous 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 fibrous layer 2b extends continuously along the longitudinal direction L, similarly to the first fibrous layer 2a (however, in the opposite direction of the thickness direction T), and also extends in the width direction (W). ) and a plurality of convex portions arranged at predetermined intervals from each other, the second lower surface 2bF protruding downward (non-skin side), and convex portions extending continuously along the longitudinal direction L and adjacent to each other. The second lower surface 2bF disposed in between may have a plurality of concave portions that are recessed toward the upper side (skin side). In that case, the positions of the convex portions 21 and recessed portions 22 of the first fibrous layer 2a and the positions of the convex portions and concave portions of the second fibrous layer 2b correspond to each other in the thickness direction T. It is desirable.

The first fiber layer 2a and the second fiber layer 2b are joined to each other by entanglement. Examples of the braiding method include the spunlace method or the water jet method. However, the bridging method is not limited to this example, and other bridging methods, such as the air-through method, may be used.

In addition, in this embodiment, the fiber density of the top part 21T of the convex part 21 is S1, the fiber density of the bottom part 22B of the concave part 22 is S2, and the fiber density of the top part 21T of the convex part 21 is S2. When the fiber density of the region MP between the top portion 21T and the bottom portion 22B of the concave portion 22 is set to S3, the relationship S1 < S3 < S2 is satisfied.

If the sanitary pad 1 has such a configuration, in the topsheet 2, from the top portion 21T of the convex portion 21 having a sparse (low density) fiber density S1, Since capillary action tends to act toward the bottom 22B of the concave portion 22 having a dense (high density) fiber density S2 via the region MP having a fiber density S3, the surface sheet 2 The liquid excretion excreted on the most skin-side surface (i.e., at or near the top 21T of the convex portion 21) is transferred to a concave portion located near the non-skin-side surface of the top sheet 2 ( With the bottom portion 22B of 22), it can be pulled in more easily. As a result, liquid excretion is more stably transferred from the skin-side surface of the topsheet 2 to the absorber 4 (and auxiliary sheet 5) via the non-skin-side surface of the topsheet 2. You can do it.

In addition, the surface sheet 2 can make it difficult to cause liquid backflow of once absorbed liquid excrement due to the above-described fiber density gradient (S1 < S3 < S2), and furthermore, the fiber density of the convex portion 21 By having a low value, a soft feel can be provided to the wearer, so the surface sheet 2 can improve absorbent performance while providing a good feel.

In addition, the sanitary pad 1 does not need to have the above-mentioned concavo-convex structure on the topsheet 2, nor does it need to have the above-mentioned fiber density gradient.

In addition, in the present embodiment, as shown in FIG. 4, the top sheet 2 has the first fiber layer 2a and the second fiber layer 2b embossed in each of the plurality of concave portions 22. It has a plurality of depressions 23 that are compressed in the thickness direction T by processing means such as the like. The plurality of recesses 23 are arranged intermittently along the longitudinal direction L in each recess 22 at equal or non-equal intervals.

In addition, the recesses 23 may be located in a position where they are aligned on the same straight line in the longitudinal direction (L) in the recessed portions 22 that are adjacent to each other in the width direction (W), or may be located at a position where they are not aligned on the same straight line. It's okay. In this embodiment, the plurality of recesses 23 are arranged in a checkerboard pattern with respect to the recesses 22, as shown in FIG. 4(a). In addition, the plan view shape of each of the plurality of depressions 23 is not particularly limited, and may be an elliptical shape as in the present embodiment or any other arbitrary shape.

When the sanitary pad 1 has such a configuration, in each of the plurality of depressions 23, the first fibrous layer 2a and the second fibrous layer 2b are pressed together in the thickness direction T. By being fixed (i.e., the water-retaining fibers F ₁ of the first fiber layer 2a are compressed), fluffing due to the water-retaining fibers F ₁ is less likely to occur, and the feel of the top sheet 2 is further improved. can be maintained.

In addition, the sanitary pad 1 does not need to have such a plurality of depressions 23 on the surface sheet 2.

(auxiliary seat)

In this embodiment, as shown in FIG. 1, the auxiliary sheet 5 extends from the front longitudinal end of the sanitary pad 1 to the rear longitudinal end of the sanitary pad 1 in the longitudinal direction (L) in plan view. ), and has a roughly rectangular, vertically elongated shape in plan view. As shown in FIG. 2, the auxiliary sheet 5 is disposed between the top sheet 2 and the absorber 4 in the thickness direction T of the sanitary pad 1, and the top sheet 2 It is composed of a liquid-permeable sheet-like member that transfers the liquid excrement that has passed through 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 it does not impair the effect of the present invention, and examples include liquid-permeable nonwoven fabric, woven fabric, and composite sheets in which these are laminated. You can.

In this embodiment, the auxiliary sheet 5 located on the non-skin side of the topsheet 2 is connected to each of the plurality of recesses 22 of the topsheet 2 (more specifically, the recesses). It is joined to the second lower surface 2bF corresponding to each of (22) by any joining means such as adhesive or heat fusion means. In this way, when the auxiliary sheet 5 and the top sheet 2 are joined to each other in each of the plurality of concave portions of the top sheet 2, the joint between the auxiliary sheet 5 and the top sheet 2 is formed with water-retaining fiber. By holding (F ₁ ), fluffing of the above-mentioned water-retaining fiber (F ₁ ) can be made more difficult to occur.

Additionally, as shown in FIG. 2, the auxiliary sheet 5 in the present embodiment has a slightly larger shape in the width direction (W) than the top sheet 2, and has both ends in the width direction (W). A pair of loop portions 5L and 5L are formed. The pair of loop portions 5L, 5L has both ends in the width direction W of the auxiliary sheet 5, respectively, on the inner side and the non-skin side in the width direction W of the auxiliary sheet 5 (thickness direction T It is formed by folding and bending the lower side of ) into a loop.

Both ends of the folded auxiliary sheet 5 are sandwiched between the top sheet 2 and the pair of side sheets 6, 6, and the pair of side sheets 6, 6 are a pair facing each other. The inner end of is joined to each other via a pair of adhesive portions (not shown) extending intermittently or continuously along the longitudinal direction (L). Additionally, the loop portion 5L does not include an elastic member.

In addition, at each end of the folded auxiliary sheet 5, the inner surfaces of the loop portions 5L (i.e., the non-skin side surfaces of the auxiliary sheet 5 before folding) are aligned in the longitudinal direction ( They are joined to each other through a pair of adhesive portions that extend intermittently or continuously along L).

Normally, in a topsheet containing a lot of water-retaining fibers, when the end edges are rubbed, the water-retaining fibers tend to loosen and fall off from the end edges. However, in this embodiment, the dimensions of the auxiliary sheet 5 in the width direction (W) is larger than the dimension in the width direction (W) of the topsheet 2, that is, both end edges of the auxiliary sheet 5 in the width direction (W) of the topsheet 2 in plan view. The outer portion extends outward in the width direction W, forming a pair of extension parts, and the pair of extension parts extends in the width direction of the auxiliary sheet 5. Since the pair of loop portions 5L and 5L described above are formed at both ends of (W), the force received from the wearer's thigh by the sanitary pad 1 is transferred to the pair of loop portions 5L and 5L (one). pair of extending portions), and it is possible to make it difficult to rub both end edges and thighs in the width direction (W) of the top sheet 2, so that the above-mentioned water-retaining fibers (F ₁ ) are spread across the width of the top sheet 2. This can make it difficult for it to come loose and fall off from both ends of the direction (W).

In addition, if the above-mentioned pair of loop parts 5L, 5L is used as a pair of directing parts, the force received by the sanitary pad 1 from the wearer's thigh is transferred to the cushion of the pair of loop parts 5L, 5L. It can be gently received by the action, and the tactile sensation given to the wearer can be improved. In particular, when the water-retaining fiber (F ₁ ) is a cotton fiber, such an effect is remarkable.

Additionally, in this embodiment, the auxiliary sheet 5 has a fiber density higher than that of the second fiber layer 2b. If the sanitary pad 1 has such a configuration, the liquid excrement drawn into the second fibrous layer 2b can be transferred more stably to the auxiliary sheet 5 by capillary action, so that the top sheet Liquid waste can be transferred more stably from (2) to the absorbent body 4 via the auxiliary sheet 5, and as a result, the feel of the top sheet 2 can be improved while the absorption performance can also be improved. there is.

Additionally, the sanitary pad 1 does not need to be provided with the auxiliary sheet 5 or the loop portion 5L.

In addition, when the auxiliary sheet 5 contains water-retaining fibers (F ₁ ) corresponding to the top sheet 2, and the top sheet 2 contains cellulose-based fibers (preferably cotton fibers), the auxiliary The sheet 5 preferably contains cellulose-based fibers (preferably cotton fibers). When the sanitary pad 1 has such a configuration, water-retaining fibers (F ₁ ) with high liquid diffusivity, preferably cellulose-based fibers, more preferably cotton fibers, are used as the agent of the top sheet 2. Since the first fiber layer 2a exists to continuously communicate with the auxiliary sheet 5 via the second fiber layer 2b, the auxiliary sheet 5 is separated from the top sheet 2 by utilizing liquid diffusion of liquid excrement by these fibers. Liquid waste can be transferred more stably to the absorbent body 4 via (5), and as a result, the feel of the top sheet 2 can be improved and the absorbent performance can be further improved.

Additionally, in the sanitary pad 1, the auxiliary sheet 5 does not need to contain water-retaining fibers, cellulose-based fibers, or cotton fibers. In that case, for example, a nonwoven fabric made of thermoplastic resin fibers can be used as the auxiliary sheet 5.

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 impair the effect of the present invention, and any size, shape, thickness, etc. can be adopted according to the desired absorption performance, flexibility, etc. .

(absorbent)

In the above-described embodiment, as shown in FIG. 1, the absorber 4 is positioned at the longitudinal center line C _L and the width direction center line C _W of the sanitary pad 1 in plan view, respectively. A vertically long plane extending over a wide area in the longitudinal direction (L) and the width direction (W), and at the same time, both ends in the longitudinal direction (L) protrude so as to draw an arc toward the outer side of the longitudinal direction (L). It has a poetic shape. As shown in FIG. 2, this absorbent body 4 is located between the top sheet 2 and the back sheet 3 (more specifically, the auxiliary sheet ( An absorbent material disposed between 5) and the back sheet 3) and having a predetermined liquid absorption performance and liquid retention performance, capable of absorbing and retaining liquid excretions such as menstrual blood that has penetrated the top sheet 2. It is formed by absence.

In the present invention, the absorbent member that can be used as the absorbent is not particularly limited as long as it can absorb and retain at least liquid excretions such as menstrual blood, and any absorbent member known in the art can be employed. Examples of such absorbent members include at least one absorbent core made of any absorbent material covered with a core wrap sheet such as tissue having hydrophilic properties. Here, examples of the absorbent material constituting the absorbent core include hydrophilic fibers and highly absorbent polymers, and more specifically, cellulose-based fibers such as ground pulp, cotton, rayon, and acetate; Granules made of highly absorbent polymers such as sodium acrylate copolymer; and mixtures combining them arbitrarily.

In the above-described embodiment, the absorbent body 4 is comprised of an absorbent core 4a made of an absorbent material and a core wrap 4b covering the absorbent core 4a.

In addition, when the topsheet 2 contains cellulose-based fibers (preferably cotton fibers), the absorber 4 contains cellulose-based fibers (preferably cotton fibers) corresponding to the topsheet 2. It is desirable to include. In that case, it is preferable that some of the cellulose-based fibers included in the topsheet 2 are in contact with the cellulose-based fibers included in the absorber 4. If the sanitary pad 1 has such a configuration, cellulose-based fibers with high liquid diffusivity are interposed from the first fibrous layer 2a to the second fibrous layer 2b of the topsheet 2 (in the case of In some cases, it exists to continuously communicate with the absorbent body 4 (via the auxiliary sheet 5), and thus, by utilizing the liquid diffusion of liquid excrement by the cellulose-based fibers, the absorbent body 4 is transferred from the top sheet 2 to the absorbent body 4. As a result, liquid excrement can be directly diffused, and as a result, absorption performance can be further improved.

Additionally, in the sanitary pad 1, the absorbent body 4 does not need to contain cellulose-based fiber or cotton.

In the present invention, the planar shape, various dimensions, basis weight, etc. of the absorbent are not particularly limited as long as it can be used as an absorbent for absorbent articles, and any planar shape according to the desired absorbent performance, flexibility, strength, etc. (e.g. , rectangular shape, oval shape, hourglass shape, etc.) or various dimensions, basis weight, etc. can be adopted.

In addition, in the present invention, when the absorbent article has a predetermined absorbent performance as a whole due to constituent members other than the absorber (for example, a top sheet, etc.), the absorbent article must contain such an absorber. You do not need to have it.

(side sheet)

In the above-described embodiment, the pair of side sheets 6, 6, as shown in FIG. 1, is located at both ends in the width direction W of the sanitary pad 1 in the longitudinal direction L in a plan view. ) has the shape of a pair of bands running in series. A pair of side sheets 6, 6 are located on the non-skin side of the top sheet 2 at both ends of the sanitary pad 1 in the width direction W, and are located on the skin side surface of the top sheet 2. By a hydrophilic or water-repellent sheet-like member that functions to spread the liquid excrement supplied to the sanitary pad 1 in the longitudinal direction (L) while preventing it from leaking outward in the width direction (W) of the sanitary pad (1). It is formed.

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 a side sheet. For example, a non-woven fabric made of fibers with hydrophilic or water-repellent properties, hydrophilic treatment, or Examples include nonwoven fabrics that have been subjected to water-repellent treatment, synthetic resin films with breathability, and the like.

Additionally, in the sanitary pad 1 of the present embodiment, the pair of side sheets 6, 6 has a dynamic friction coefficient when wet that is lower than the dynamic friction coefficient when wet of the top sheet 2. . The pair of side sheets 6, 6, which are easily in contact with the skin around the wearer's legs, have a lower coefficient of dynamic friction than the above-mentioned top sheet 2, which has excellent feel, and thus provides a smoother sanitary pad 1. It can provide a sense of touch.

Here, the dynamic friction coefficient during wetting can be measured according to the following method.

(1) The top sheet and side sheet of the absorbent article are cut, and samples measuring 40 mm in the width direction and 80 mm in the length direction are cut. Additionally, if these sheets cannot be separated by an adhesive such as a hot melt (HMA) type adhesive, the adhesive is washed off using toluene and then dried in the air for 24 hours.

(2) A 10 mm longitudinal end of each sample is fixed to a horizontal board using gum tape (Askool Co., Ltd.: "Field Power" fabric tape 0.26 mm thick, 50 mm wide x 25 m long roll).

(3) On each sample, a digital force gauge (Nippon Densan Shimpo Co., Ltd., FGP-0.5 (FGP-2)) and a gold canequim (50 mm x 40 mm, JIS) with the 10 mm end joined to the entire surface were placed. Install the attached white cloth (Japanese Standards Association, single fiber cloth) for dye fastness test in compliance with L 0803. Additionally, a 525g weight, which is a rectangular shape with a bottom of 35mm x 25mm, is placed on top of it.

(4) A gold gun moistened with a predetermined amount of ion-exchanged water on an average basis is moved 30 mm across the sheet at a speed of 100 mm/min, and the maximum value displayed at that time is taken as the dynamic friction coefficient. At this time, a gold key is placed on the skin-side surface of each sample.

In this measurement method, the wet skin of the wearer is reproduced by wetting the gold gun, and the amount of skin moisture reproduced is based on 60% of wetness.

Therefore, the predetermined amount of ion-exchanged water is 60% by mass with respect to the mass of the gold gun. Specifically, when the gold weight of 40 mm x 50 mm is 50 g/m 2, it is set to 0.06 mL (50 g/m 2 x 0.04 m x 0.05 m x 60%).

Additionally, if the sheet cannot be sampled at the above-mentioned width dimension, a sample is sampled at the maximum width that can be sampled and measured. Next, a weight that fits within the sheet area and has a weight of 30 g/cm2 and a gold key with a weight width of +10 mm (connection part of the digital force gauge) are placed, and the sheet is moved the maximum distance at a speed of 100 mm/min. The maximum value is taken as the dynamic friction coefficient.

Additionally, in this embodiment, the dynamic friction coefficient of the top sheet 2 when wet is 0.80, and the dynamic friction coefficient of the side sheet 6 when wet is 0.49. Additionally, the difference between the dynamic friction coefficient of the top sheet 2 and the dynamic friction coefficient of the side sheet 6 can be, for example, 0.1 or more and 0.25 or less. If the difference in the coefficient of dynamic friction is within this range, it becomes easy for the wearer to feel the difference in surface properties between the top sheet 2 and the side sheet 6.

In addition, the pair of side sheets 6, 6 with such a low dynamic friction coefficient uses a low friction material as the material forming the side sheets 6, 6 (for example, constituent fibers of non-woven fabric, etc.) Alternatively, it can be formed by coating the skin-side surface of a known sheet-like member used as a side sheet with a low-friction material.

In addition, the low friction material that can be used for the side sheet is not particularly limited, but for example, olefin resins such as polyethylene and polypropylene, silicone resins, and fluororesins such as polytetrafluoroethylene have a high friction coefficient. Low-lying resins, or resin compositions containing these resins, etc. can be mentioned.

Additionally, the dynamic friction coefficient of the pair of side sheets 6, 6 when wet does not have to be lower than the dynamic friction coefficient of the top sheet 2 when wet.

In the present invention, the planar shape and various dimensions of each pair of side sheets are not particularly limited as long as they can be used as side sheets of absorbent articles, and can be optional depending on the desired air leakage performance, water absorption performance, etc. The planar shape or various dimensions can be adopted.

Additionally, since it is not an essential structural requirement for the absorbent article of the present invention that the absorbent article be provided with such a pair of side sheets, the absorbent article does not need to be provided with such a pair of side sheets.

(back sheet)

In the sanitary pad 1 of the above-described embodiment, the back sheet 3 has a length from the front longitudinal end of the sanitary pad 1 to the rear side in plan view, as shown in FIG. 1. It extends in the longitudinal direction (L) across the sanitary pad 1, and extends in the width direction (W) from the width direction end on one side to the width direction end on the other side in the width direction (W) of the sanitary pad 1. It has a serial, vertically long planar shape. As shown in FIG. 2, this backsheet 3 is disposed at a position on the non-skin side in the thickness direction T of the sanitary pad 1, and passes through the absorber 4 or passes through the absorber 4. It is comprised of a liquid-impermeable sheet-like member that functions to prevent liquid excrement seeping out from leaking to the outside of the sanitary pad 1.

The liquid-impermeable sheet-like member that can be used as the backsheet 3 is one that can prevent the penetration of liquid excretions such as menstrual blood discharged from the wearer and prevent the liquid excretions from leaking through the wearer's clothing, etc. , is not particularly limited, and includes, for example, any hydrophobic thermoplastic resin fiber (e.g., polyolefin-based fibers such as PE and PP, polyester-based fibers such as polyethylene terephthalate (PET), core-sheath type composite fibers, etc. Hydrophobic nonwoven fabric formed by various composite fibers, etc.); A porous or non-porous resin film formed from a hydrophobic thermoplastic resin such as PE or PP; A laminate obtained by bonding a nonwoven fabric to the resin film; Any liquid-impermeable sheet-like member, such as a laminated non-woven fabric such as SMS non-woven fabric, can be used.

Additionally, the planar shape, various dimensions, basis weight, etc. of the backsheet 3 are not particularly limited as long as it can be used as a backsheet, and may be any planar shape, various dimensions, basis weight, etc. according to the desired water repellency performance, breathability, strength, etc. etc. can be employed.

In addition, in the sanitary pad 1 of this embodiment, the top sheet 2 is joined to the auxiliary sheet 5 with an adhesive or the like (for example, a hot melt adhesive or the like), and the auxiliary sheet 5 and the portion of each of the pair of side sheets 6, 6 facing the absorber 4 is joined to the absorber 4 with an adhesive or the like, and the pair of side sheets 6, 6 and the portion of each of the absorbers 4 facing the backsheet 3 is joined to the backsheet 3 with an adhesive or the like.

(Adhesive part)

In this embodiment, the sanitary pad 1 is attached to the wearer's clothing (for example, underwear, etc.) on the non-skin side surface of the backsheet 3, as shown in FIG. 2. It is further provided with a plurality of adhesive parts (7) and a pair of adhesive parts (8, 8) for fixing (1).

The plurality of adhesive portions 7 are disposed on the surface of the backsheet 3 on the non-skin side so as to overlap the absorber 4 in the thickness direction T, and extend continuously in the longitudinal direction L and have a width. It has a planar shape of a plurality of stripes (multiple strands of approximately rectangular shape) arranged intermittently in the direction W.

Additionally, the pair of adhesive portions 8, 8 are disposed on the non-skin side surface of the backsheet 3 so as to overlap the pair of wing portions 9, 9 in the thickness direction T, and extend in the longitudinal direction. It has a roughly rectangular shape in plan view extending continuously in (L).

Additionally, these adhesive portions 7 and 8 are not particularly limited as long as they are capable of fixing the sanitary pad 1 to the wearer's clothing, and may be formed of any adhesive such as, for example, a styrene-based polymer. You can.

In addition, since it is not an essential structural requirement for the absorbent article of the present invention for the absorbent article to have such an adhesive portion, the absorbent article does not need to have such an adhesive portion.

[Manufacturing method]

Next, a method for manufacturing the top sheet 2 of the sanitary pad 1 according to the above-described embodiment will be described by way of example.

(Second fiber web forming process)

First, water-retaining fibers (F ₁ ) and thermoplastic resin fibers (F ₂ ) for forming the second fiber layer 2b are placed on a first card machine (for example, a dry roller card using a single card or a double card). supplied, forming a second fibrous web corresponding to the second fibrous layer 2b. This second fiber web is conveyed in the conveyance direction (MD) by a conveyance device.

(First fiber web forming process)

Next, the water-retaining fibers (F ₁ ) for forming the first fibrous layer 2a are provided to a second card machine (dry roller card similar to the first card machine), and the water-retaining fibers F 1 corresponding to the first fibrous layer 2a are provided. A first fibrous web is formed.

(Fiber web lamination process)

The formed first fibrous web is laminated on the second fibrous web being conveyed by a conveying device. This forms a composite fiber web with a two-layer structure in which the first fiber web and the second fiber web are laminated.

Additionally, the ratio of each fiber in each fiber web can be controlled by the ratio of raw material fibers supplied to each card machine.

(Confusion process)

Next, the composite fiber web having a two-layer structure is subjected to water jet treatment using a water jet treatment machine, and the fibers in the composite fiber web are entangled with water flow. By this, a composite fiber sheet (spunlace nonwoven fabric) is formed.

In this way, the fibers in the composite fiber web are entangled as a whole by water flow entanglement, making it difficult for the water-retaining fibers (F ₁ ), such as cotton fibers, to unravel and fall out, and it is also easy to obtain a good feel.

Here, in the above-described water jet treatment, a high-pressure jet water stream is sprayed from the upper surface of a composite fiber web placed on a continuously moving mesh belt, and the fibers in the composite fiber web are entangled by the action of the water flow. It will happen.

In addition, the properties of the composite fiber sheet obtained by water jet treatment can be adjusted appropriately depending on the mass of each fiber web, the hole diameter of the spray nozzle, the number of holes (pitch) of the spray nozzle, the moving speed of the fiber web, etc.

In addition, the method of forming the fibrous web corresponding to each fibrous layer is not limited to the above method, and for example, a wet method or the like may be employed. In addition, the method of joining the web is not limited to the above-mentioned method, and may include, for example, the air-through method (i.e., the composite fiber web is conveyed to a heating device, and within the heating device, heated air is applied to the composite fiber web. A method of entangling fibers) or a needle punch method may be employed.

(drying process)

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

(heat treatment process)

Additionally, the dried composite fiber sheet is transported to a heat treatment device (heating type hot air oven) and heat treated with hot air at a predetermined temperature. By this heat treatment, at least a portion of the thermoplastic resin fibers (F ₂ ) in the composite fiber sheet are melted, and the melt (F _2M ) flows within the composite fiber sheet and exists in a portion corresponding to the first fiber layer (2a). It attaches to the water-retaining fibers (F ₁ ) or the water-retaining fibers (F ₁ ) in the entangled portion (P _E ) of the composite fiber sheet. As a result, at least some of the water-retaining fibers (F ₁ ) included in the portion corresponding to the first fiber layer 2a are in at least some of the entangled portions (P _E ) of the intertwined portions (P _E ) of the fibers. , is covered by a melt (F _2M ) of thermoplastic resin fibers (F ₂ ).

In addition, the conditions of the heat treatment are not particularly limited as long as the thermoplastic resin fiber (F ₂ ) can be melted, but the thermoplastic resin fiber (F ₂ ) is a composite fiber such as a core-sheath type composite fiber or a side-by-side type composite fiber. In this case, only the resin component with a low melting point exposed to the surface of the composite fiber (for example, the resin component constituting the sheath in the case of a core-sheath type composite fiber, and the resin component on one side in the case of a side-by-side type composite fiber) It is desirable to adopt melting temperature conditions.

In addition, the equipment used for drying after the above-described water jet treatment and the subsequent heat treatment (i.e., a dryer and a heat treatment apparatus) may be used together.

(Shaping process)

Next, the composite fiber sheet after heat treatment is supplied to the shaping device while being transported in the transport direction (MD). Here, the shaping device is provided with a pair of shaping rolls that are successively installed in the circumferential direction on the outer peripheral surface and have concave portions and convex portions that engage with each other, and the composite fiber sheet after heat treatment is formed on the pair of shaping rolls. The above-mentioned specific concavo-convex structure is sandwiched between the concave portion and the convex portion and extends in the conveyance direction (MD).

Additionally, if the surface sheet 2 does not have such a specific concavo-convex structure, the shaping process may be omitted.

In this way, the composite fiber shaped sheet for the top sheet 2 is formed. Additionally, the composite fiber shaped sheet is laminated with sheet-like members for other structural members of the sanitary pad 1 and then cut into the shape of the sanitary pad 1 to become the top sheet 2.

In addition to the sanitary pad of the above-described embodiment, the present invention can be applied to various absorbent articles such as panty liners, (light) incontinence pads, and disposable diapers. In addition, the absorbent article of the present invention is not limited to the above-described embodiments or the examples described later, and can be appropriately combined, replaced, changed, etc. without departing from the purpose and spirit of the present invention.

In addition, the nonwoven fabric having a first fiber layer and a second fiber layer used in the surface sheet of the absorbent article of the present invention is a nonwoven fabric that is difficult to cause unpleasant irritation to the user's skin and has excellent feel, so it can be used in other applications requiring good feel. Application to sheet-like members (e.g., side sheets, exterior sheets, etc.) is also possible, and furthermore, it can be applied to sanitary products other than absorbent articles (e.g., masks, dirt-wiping sheets, face masks, cosmetic sheets, Application to nonwoven fabrics used for puffs (e.g., cotton puffs, etc.) is also possible.

When applied to such a nonwoven fabric, the nonwoven fabric is a nonwoven fabric having a first side and a second side,

The nonwoven fabric is,

a first fiber layer comprising water-retaining fibers and forming the first side of the nonwoven fabric;

A second fiber layer comprising thermoplastic resin fibers and water-retaining fibers, and forming the second side of the nonwoven fabric adjacent to the second side of the first fiber layer,

The proportion of the water-retaining fibers in the fibers constituting the first fibrous layer is greater than the proportion of the water-retaining fibers in the fibers constituting the second fibrous layer,

At least some of the water-retaining fibers included in the first fiber layer become the nonwoven fabric in which at least some of the interwoven portions of the fibers are covered with a melt of the thermoplastic resin fibers.

Example

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the present invention is not limited to these examples.

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

Example 1

First, water-retaining fibers and thermoplastic resin fibers for forming the second fiber layer include cotton fibers (fiber length 5 mm to 35 mm, basis weight 16 g/m2) and core-sheath type composite fibers (core: PP, sheath: PE, fiber length 38 mm, basis weight of 4 g/m2) was prepared, and these fibers were supplied to the first card machine to form a second fiber web corresponding to the second fiber layer (second fiber web forming step). The mixing ratio (mass ratio) of cotton fibers and core-sheath type composite fibers in this second fiber web was cotton fiber: core-sheath type composite fiber = 60:40.

Next, only cotton fibers (fiber length 20 mm to 35 mm, basis weight 10 g/m2) are prepared as water-retaining fibers for forming the first fiber layer, and these cotton fibers are supplied to a second card machine to form the first fiber corresponding to the first fiber layer. A web was formed (first fiber web forming process).

Then, the formed first fiber web is laminated on the second fiber web being transported by the conveying device, thereby forming a composite fiber web with a two-layer structure in which the first fiber web and the second fiber web are laminated (fiber web lamination) After this, this composite fiber web was subjected to a water jet treatment using a water jet treatment machine to entangle the fibers in the composite fiber web with water flow, thereby obtaining a composite fiber sheet (spunlace nonwoven fabric) (entanglement process).

The composite fiber sheet that passed through the water jet processor was transported to a dryer (heated hot air oven) and dried with hot air at 70°C (drying process).

Additionally, the dried composite fiber sheet is transported to a heat treatment device (heated hot air oven) and heat-treated with hot air at 130° C., so that the cotton fibers are formed into a melt of core-sheath type composite fibers (specifically, at the intertwined portion of the fibers). It was coated with a melt of PE at the beginning (heat treatment process).

Next, the heat-treated composite fiber sheet is supplied to a shaping device equipped with a pair of shaping rolls having concave portions and convex portions that engage with each other, sandwiched between the concave portions and convex portions of the pair of shaping rolls, and conveyed. An uneven structure extending in the direction (MD) was shaped (shaping process).

The composite fiber shaped sheet with the concavo-convex structure shaped in this way was cut into a predetermined shape to obtain the top sheet of Example 1.

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 the shaping process were not performed.

Comparative Example 2

Only cotton fibers (fiber length 20 mm to 35 mm, basis weight 30 g/m2) were used as fibers to form the top sheet (i.e., the top sheet was a single-layer fiber layer (cotton fiber layer) without a second fiber layer), The surface sheet of Comparative Example 2 was obtained in the same manner as in Example 1, except that the heat treatment process and the shaping process were not performed.

Regarding the surface sheet of Example 1, the state within the first fiber layer was observed with a scanning electron microscope, and the cotton fibers (water-retaining fibers (F ₁ )) were found to be core- _sheath type composite fibers ( It was confirmed that it was covered with a melt of thermoplastic resin fiber (F ₂ ) (specifically, a melt of PE at the beginning) (F _{2 M} ). The confirmation result (that is, an electron micrograph of the first fibrous layer in the top sheet of Example 1) is shown in Figure 5.

In addition, for each of the surface sheets of Example 1, Comparative Example 1, and Comparative Example 2, the occurrence of fluffing of each surface sheet was compared and evaluated according to the following <Method for evaluating fluffing by friction fastness test>. . The evaluation results (i.e., comparative photographs showing the occurrence of fluffing in Example 1 and Comparative Examples 1 and 2) are shown in Figure 6.

＜Evaluation method for fluffing by friction fastness test＞

(1) From the nonwoven fabric constituting the top sheet, the area to be measured is cut to a predetermined size (for example, 80 mm x 40 mm) to obtain a sample for measurement.

(2) The sample for measurement is fixed on the measurement stage of a dyeing material friction fastness tester (manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.).

(3) A weight of 200 g is attached to the upper surface of the friction terminal of the dyeing area friction fastness tester, and a fabric tape forming a friction surface is attached to the lower surface.

(4) The surface of the measurement sample fixed on the measurement stage is rubbed with the friction surface of the friction terminal described above. At this time, the number of reciprocations of the friction terminal is 100 and 200 times, and the movement range (reciprocation width) of the friction terminal is 60 mm. In addition, the items “0T”, “100T”, and “200T” shown in FIG. 6 indicate that the number of reciprocations of the friction terminal in the friction fastness test (FF) is “0,” “100,” and “200,” respectively. It means ‘sashimi’.

(5) Observe the fluffing state of the surface of the measurement sample after rubbing it with a friction terminal.

As shown in FIG. 6, the surface sheet of Example 1, in which heat treatment was performed and the cotton fibers were coated with a melt of core-sheath type composite fibers at the intertwined portion of the fibers, even after being rubbed 200 times with a friction terminal, It can be seen that almost no fluffing occurs, and the texture is excellent (see the photo in column A in Fig. 6).

On the other hand, it can be seen that the surface sheets of Comparative Examples 1 and 2, on which no heat treatment was performed, fluffed up even after being rubbed 100 times with a friction terminal, and the texture was deteriorated (Fig. 6 (Refer to the photos of Column B (Comparative Example 1) and Column C (Comparative Example 2) in ).

1: Sanitary pad (an example of an absorbent article) 2: Surface sheet
2a: first fiber layer 2b: second fiber layer
3: Back sheet 4: Absorber
5: Auxiliary seat 6: Side seat
F ₁ : Water-retaining fiber F ₂ : Thermoplastic resin fiber
F _2M : melt

Claims (13)

An absorbent article comprising a surface sheet,
The surface sheet is,
a first fiber layer comprising water-retaining fibers and forming a skin-side surface of the topsheet;
A second fiber layer comprising thermoplastic resin fibers and water-retaining fibers, and forming a surface on a non-skin side of the top sheet adjacent to the non-skin side of the first fiber layer,
The proportion of the water-retaining fibers in the fibers constituting the first fibrous layer is greater than the proportion of the water-retaining fibers in the fibers constituting the second fibrous layer,
At least a portion of the water-retaining fibers included in the first fiber layer are covered with a melt of the thermoplastic resin fibers at at least a portion of the water-retaining fibers intertwined with each other,
The absorbent article, wherein the ratio of the water-retaining fibers in the second fiber layer is 50% by mass to 90% by mass with respect to the total mass of all constituent fibers of the second fiber layer. According to claim 1,
In the thermoplastic resin fiber, one strand of thermoplastic resin fiber is entangled with a plurality of strands of the water-retaining fiber,
An absorbent article, wherein each of the intertwined portions of the single strand of thermoplastic resin fiber and the plurality of water-retaining fibers is coated with a melt of the single strand of thermoplastic resin fiber. The method of claim 1 or 2,
An absorbent article in which the melt of the thermoplastic resin fibers is not exposed to the skin-side surface of the first fiber layer. The method of claim 1 or 2,
An absorbent article in which the average fiber length of the water-retaining fibers included in at least the first fiber layer is shorter than the average fiber length of the thermoplastic resin fibers. The method of claim 1 or 2,
An absorbent article wherein the water-retaining fibers included in at least the first fiber layer have an average fiber length of 5 mm or more and less than 35 mm. The method of claim 1 or 2,
The thermoplastic resin fiber is a composite fiber,
The composite fiber is an absorbent article in which a resin component with a low melting point is exposed on the surface of the composite fiber. The method of claim 1 or 2,
An absorbent article in which the top sheet has a pressed portion that is recessed in the thickness direction from the skin-side surface. The method of claim 1 or 2,
The surface sheet is,
a plurality of protrusions extending along the longitudinal direction of the absorbent article and positioned at intervals in the width direction of the absorbent article;
An absorbent article extending along the longitudinal direction of the absorbent article and having a plurality of concave portions located between adjacent convex portions. According to claim 8,
The absorbent article further includes an auxiliary sheet located on a non-skin side of the surface sheet,
An absorbent article, wherein the top sheet is bonded to the auxiliary sheet in each of the plurality of recesses. The method of claim 1 or 2,
An absorbent article, wherein the water-retaining fiber is organic cotton. The method of claim 1 or 2,
An absorbent article in which the fiber density of the second fiber layer is greater than that of the first fiber layer. The method of claim 1 or 2,
An absorbent article wherein 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 method of claim 1 or 2,
The absorbent article further includes a pair of side sheets positioned on the skin side of the top sheet at both ends in the width direction,
An absorbent article in which the pair of side sheets has a coefficient of dynamic friction when wet, which is lower than that of the top sheet when wet.