JP2023019810A - Nonwoven fabric for absorbent articles and absorbent articles comprising the same - Google Patents

Abstract

To provide nonwoven fabric for an absorbent article which has constituent fibers being slight in fluffing and which has excellent touch feeling, and to provide an absorbent article provided with the nonwoven fabric.SOLUTION: Nonwoven fabric for an absorbent article includes a first fiber layer, and a second fiber layer disposed adjacent to the first fiber layer. The nonwoven fabric contains 0.5 - 3.0 mass % of natural fiber. The natural fiber and first hot-melt core-sheath composite fiber having fineness of 1.5 - 3.0 dtex are included as fibers constituting the first fiber layer. Second hot-melt core-sheath composite fiber having fineness of 0.5 dtex or more and less than 1.5 dtex is included as fibers constituting the second fiber layer. An absorbent article provided with the nonwoven fabric is also provided.SELECTED DRAWING: None

Description

The present invention relates to a nonwoven fabric for absorbent articles and absorbent articles comprising the same.

BACKGROUND ART Absorbent articles such as disposable diapers are sometimes used for the purpose of improving hygroscopicity and texture using nonwoven fabrics containing natural fibers as their constituent members. In Patent Document 1, synthetic fibers and cotton fibers are included, the weight ratio of cotton fibers is less than 50%, and the number of cotton fibers having a fiber length of less than 0.3 mm is a fiber having a fiber length of 0.3 mm or more No more than 1% of the number of nonwoven fabrics are disclosed.

Patent Document 2 discloses a nonwoven fabric including a first fiber layer containing first sheath-core conjugate fibers and a second fiber layer containing second sheath-core conjugate fibers and cotton.

JP 2018-178355 A WO2020/004554 pamphlet

Non-woven fabrics containing natural fibers may expose the constituent fibers such as natural fibers on the surface of the non-woven fabric when using an absorbent article comprising the same, and the constituent fibers may become fuzzy. Texture such as smoothness may deteriorate. However, the techniques described in Patent Documents 1 and 2 cannot be said to be sufficient in reducing fluffiness of constituent fibers and improving texture, and there is room for improvement in this respect.

Accordingly, the present invention relates to a nonwoven fabric for absorbent articles having less fluffing of constituent fibers and excellent in texture, and an absorbent article comprising the same.

The present invention relates to nonwoven fabrics for absorbent articles.
Preferably, the nonwoven fabric comprises a first fibrous layer and a second fibrous layer arranged adjacent to the first fibrous layer.
The nonwoven fabric preferably contains 0.5% by mass or more and 3.0% by mass or less of natural fibers.
The first fiber layer preferably contains natural fibers and first heat-fusible core-sheath composite fibers having a fineness of 1.5 dtex or more and 3.0 dtex or less as its constituent fibers.
It is preferable that the second fiber layer contains, as constituent fibers, second heat-fusible core-sheath composite fibers having a fineness of 0.5 dtex or more and less than 1.5 dtex.

The present invention also relates to an absorbent article comprising the nonwoven fabric.
Other features of the invention will become apparent from the claims and the following description.

ADVANTAGE OF THE INVENTION According to this invention, the nonwoven fabric for absorbent articles which has few fluffs of a constituent fiber, and is excellent in a touch, and an absorbent article provided with the same are provided.

The present invention will be described below based on its preferred embodiments. The nonwoven fabric for absorbent articles of the present invention (hereinafter also simply referred to as nonwoven fabric) is suitably used as a constituent member of absorbent articles. Examples of absorbent articles include, but are not limited to, disposable diapers, incontinence pads, sanitary napkins, panty liners, and the like. broadly inclusive.

The nonwoven fabric for absorbent articles of the present invention is a sheet-like material having a multi-layer structure including a first fiber layer and a second fiber layer arranged adjacent to the first fiber layer. The constituent fibers of the nonwoven fabric for absorbent articles maintain the form of the fiber sheet by at least one of entanglement, fusion bonding, and pressure bonding. The boundary between the first fiber layer and the second fiber layer may be clear or unclear.

The nonwoven fabric for absorbent articles may be composed of a two-layer structure consisting of only the first fiber layer and the second fiber layer, and in addition to the first fiber layer and the second fiber layer, further includes another fiber layer 3 It may have a structure of layers or more. When the nonwoven fabric for absorbent articles has a two-layer structure, the first fiber layer includes the first surface, which is one outer surface of the nonwoven fabric for absorbent articles. The second fiber layer is the other outer surface of the nonwoven fabric for absorbent articles, and includes a second surface opposite to the first surface.

The nonwoven fabric for absorbent articles contains a predetermined amount of natural fibers. By including natural fibers in the nonwoven fabric, the nonwoven fabric for absorbent articles can exhibit good texture such as softness and smoothness, and when the nonwoven fabric is used as a constituent material of the absorbent article, it can be used during wearing. It is possible to reduce stuffiness when wearing the absorbent article by exhibiting an appropriate hygroscopicity of the absorbent article, and improve the feeling of use of the absorbent article.

Specifically, the content of natural fibers in the nonwoven fabric for absorbent articles is 0.5% by mass or more, preferably 0.6% by mass or more, more preferably 0.7% by mass or more, and , 3.0% by mass or less, preferably 2.0% by mass or less, and more preferably 1.5% by mass or less. By including the natural fibers in such a range, it is possible to reduce fluffing of the constituent fibers of the nonwoven fabric, and to further enhance the feel resulting from improvement in softness and smoothness. Furthermore, the softness and smoothness of the absorbent article using this nonwoven fabric can improve the texture and feeling of use.

Natural fibers include, for example, natural cellulose fibers such as pulp fibers, cotton fibers, and linen fibers, and cotton fibers are preferable from the viewpoint of improving the texture due to workability and softness while reducing manufacturing costs. In general, these natural fibers do not have the function of being fused with other fibers by the action of heat, and are excluded from the heat-fusible fibers described below.

Nonwoven fabrics for absorbent articles contain two types of heat-fusible core-sheath composite fibers having different finenesses in addition to natural fibers as constituent fibers.
Specifically, the first fiber layer includes natural fibers and first heat-fusible core-sheath composite fibers having a predetermined fineness (hereinafter also referred to as "first core-sheath fibers") as constituent fibers. .)including. The first fiber layer preferably consists of natural fibers and first core-sheath fibers, excluding fibers that are unavoidably mixed.
In addition to this, the second fiber layer includes, as its constituent fibers, second heat-fusible core-sheath composite fibers (hereinafter also referred to as "second core-sheath fibers") having a fineness smaller than that of the first core-sheath fibers. ). It is preferable that the second fiber layer consists of the second core-sheath fibers, excluding fibers that are unavoidably mixed.

By arranging different types and finenesses of fibers constituting each fiber layer, it is possible to unexpectedly reduce fluffing and falling of fibers from the nonwoven fabric, improve the smoothness of the nonwoven fabric, and improve the texture. When used as a constituent member of an absorbent article, it is possible to efficiently control the humidity during wearing while improving the texture, so that the feeling of use is improved.

The heat-fusible core-sheath conjugate fibers contained in each fiber layer are fibers that are independently fused with other fibers by the action of heat, and are made of thermoplastic resin as a raw material. Thermoplastic resins include polyolefin resins such as polyethylene (PE) and polypropylene (PP), polyester resins such as polyethylene terephthalate (PET), vinyl resins such as polyvinyl chloride and polystyrene, polyacrylic acid and polymethyl methacrylate, and the like. acrylic resins, fluorine resins such as polyperfluoroethylene, and polyamide resins. These resins can be used individually by 1 type or in combination of 2 or more types.

A core-sheath composite fiber is a composite fiber composed of a core containing a resin component with a high melting point and a sheath in which the outer periphery of the core is coated with a resin component with a low melting point. Examples of such core-sheath composite fibers include PET/PP, PET/PE, PE/PP and the like as core/sheath combinations independently, but not limited to these combinations. The core-sheath type conjugate fiber may be of a concentric type or an eccentric type.

The fineness of the first core-sheath fiber is 1.5 dtex or more, preferably 1.6 dtex or more, more preferably 1.7 dtex or more, and 3.0 dtex or less, preferably 2.6 dtex or less. , more preferably 2.4 dtex or less. When the first core-sheath fibers have such a fineness, the nonwoven fabric can be easily made bulky, resulting in a highly flexible nonwoven fabric.

The fineness of the second core-sheath fiber is 0.5 dtex or more, preferably 0.6 dtex or more, more preferably 0.7 dtex or more, and less than 1.5 dtex, preferably 1.4 dtex or less. , more preferably 1.3 dtex or less.
Since the second core-sheath fibers have such a fineness, the fiber density of the second fiber layer can be easily made high while sufficiently exhibiting the heat fusion of the constituent fibers. The fusion between the sheath fibers makes it easier to retain the natural fibers in the nonwoven fabric, and to easily retain the natural fibers that have unintentionally migrated between the fiber layers by entangling them between the constituent fibers in the second fiber layer. As a result, while sufficiently exhibiting the strength of the nonwoven fabric, the constituent fibers of the nonwoven fabric, in particular, the natural fibers that are not heat-fusible fibers can be efficiently suppressed from becoming fuzzy or falling off, and the smoothness of the nonwoven fabric can be improved to further improve the texture. improves.
Further, by setting the fineness of the first core-sheath fiber and the fineness of the second core-sheath fiber within the ranges described above, it is possible to obtain a nonwoven fabric having high tensile strength, and even if the nonwoven fabric is transported to other processes after its production. can maintain its strength. In addition to this, it has sufficient strength to withstand actual use and is excellent in handleability.

The fineness of each core-sheath fiber can be measured by the following method. A nonwoven fabric to be measured is cut into a rectangular shape of 50 mm×100 mm (5000 mm ² in area) to prepare a sample for measurement. Next, the measurement sample is viewed in cross section, and the fiber thickness is measured with an electron microscope for 10 standard fibers at a position spaced 0.05 mm in the thickness direction from one surface of the measurement sample. , and calculate the average fiber thickness Dn (μm). Next, a standard fiber constituent resin is specified at a position spaced 0.05 mm in the thickness direction from the first surface of the measurement sample, and a differential scanning calorimeter (DSC) is used to determine the theoretical fiber existence. Obtain the density Pn (g/cm ³ ). From the obtained fiber thickness average value Dn (μm) and theoretical fiber existence density Pn (g/cm ³ ), the weight (g) per 10000 m fiber length is calculated, and this calculated value is the first It is defined as the fineness (dtex) of the core-sheath fiber.
Similarly, the other surface of the measurement sample is subjected to the above-described measurement method, and the calculated value is taken as the fineness (dtex) of the second core-sheath fiber.

As described above, the first fiber layer contains natural fibers and first core-sheath fibers, and the content of the first core-sheath fibers in the first fiber layer is preferably 90.0% by mass or more. , more preferably 95.0% by mass or more, still more preferably 97.0% by mass or more, preferably 99.5% by mass or less, more preferably 99.0% by mass or less.
By setting such a content ratio, the fusibility of the constituent fibers in the first fiber layer and between the first fiber layer and the second fiber layer is enhanced, and the fluffing and falling off of the natural fibers are efficiently reduced. , even when natural fibers are contained, the strength of the nonwoven fabric can be fully expressed. In addition, when such a nonwoven fabric is used as a constituent member of an absorbent article, the adhesiveness to constituent members other than the nonwoven fabric is sufficiently enhanced to form an absorbent article having practically sufficient strength. It's easy to do.

In addition, the content of natural fibers in the first fiber layer is preferably 0.5% by mass or more, more preferably 0.8% by mass or more, and still more preferably, provided that the content of the entire nonwoven fabric described above is satisfied. is 1.0% by mass or more, preferably 3.0% by mass or less, more preferably 2.8% by mass or less, and even more preferably 2.5% by mass or less. By setting such a content ratio, the nonwoven fabric exhibits appropriate hygroscopicity, while the softness is enhanced and the touch is good, making it easy to remind the wearer of the gentleness to the skin. In addition, it is possible to reduce fluffing of the constituent fibers of the nonwoven fabric and further improve the texture by improving the smoothness. In addition to this, the softness and smoothness of the absorbent article using this nonwoven fabric can be improved, thereby improving the texture and feeling of use.

The content of the second core-sheath fibers in the second fiber layer is preferably 90.0% by mass or more, more preferably 95.0% by mass or more, still more preferably 98.0% by mass or more, and preferably 100% by mass. % by mass or 100% by mass or less.
By setting such a content ratio, the fusibility of the constituent fibers in the second fiber layer and between the first and second fiber layers is enhanced, and fluffing and shedding of the natural fibers can be efficiently reduced. In addition to this, the fiber density of the second fiber layer can be increased to form a dense structure. Since the natural fibers contained in the first fiber layer pass through the second fiber layer in the thickness direction and are effectively prevented from falling off or becoming fuzzy, the nonwoven fabric and the absorbent article comprising the same can be effectively prevented from falling off or becoming fuzzy. The texture and usability are further improved.

The nonwoven fabric for absorbent articles preferably has a different fiber density in one fiber layer and a fiber density in the other fiber layer of the nonwoven fabric. is preferably higher than the fiber density of the constituent fibers.

Specifically, the fiber density of the first fiber layer is preferably 20 fibers/mm ² or more, more preferably 25 fibers/mm ² or more, still more preferably 30 fibers/mm ² or more, and preferably 80 fibers/mm. ² or less, more preferably 70 lines/mm ² or less, and even more preferably 65 lines/mm ² or less. With such a configuration, the cushioning properties and softness of the nonwoven fabric can be further improved.

Further, the fiber density of the second fiber layer is preferably 30 fibers/mm ² or more, more preferably 40 fibers/mm ² or more, still more preferably 50 fibers/mm ² or more, and preferably 200 fibers/mm ² or less. , more preferably 150 lines/mm ² or less, and still more preferably 130 lines/mm ² or less. With such a structure, the non-woven fabric can be further improved in its fluffiness and smoothness.

The fiber density of each fiber layer in a nonwoven fabric can be measured by the following method, taking a nonwoven fabric having a first fiber layer and a second fiber layer as an example.
First, a razor (Product No. FAS-10, manufactured by Feather Safety Razor Co., Ltd.) is used to cut the nonwoven fabric along the thickness direction. Then, the cut surface of the nonwoven fabric is divided into three equal parts in the thickness direction, and the part on one side of the nonwoven fabric and the part on the other side of the nonwoven fabric are enlarged using a scanning electron microscope (fiber cross section is 30 to 30%). Adjust the magnification so that about 60 lines can be measured; 150 to 500 times). At each site, the number of cross-sections of cut fibers present in the field of view per fixed area (about 0.5 mm ² ) is counted. Then, the measured value of each part is converted into the number of fiber cross sections per 1 mm ² . The measurement is performed at three locations on the same fiber layer, and the arithmetic mean value is taken as the fiber density of each fiber layer. JCM-5100 (trade name) manufactured by JEOL Ltd. is used as the scanning electron microscope.
The fiber layer is specified by measuring the fineness of the fibers present on one side of the nonwoven fabric and the fineness of the fibers present on the other side of the nonwoven fabric according to the above measurement method, and determining the fineness of each site. is measured, and the portion containing fibers with a fineness of 1.5 dtex or more is defined as the first fiber layer, and the portion containing fibers with a fineness of less than 1.5 dtex is defined as the second fiber layer.

The nonwoven fabric for absorbent articles has a tensile strength of preferably 20 N/50 mm or more, more preferably 30 N/50 mm or more, and still more preferably 35 N/50 mm or more in the machine direction (MD direction) of the product as one direction, Also, it is preferably 70 N/50 mm or less, more preferably 60 N/50 mm or less, and still more preferably 50 N/50 mm or less. As a result, the nonwoven fabric for absorbent articles can maintain its strength even when it is transported to other processes after its production, and has sufficient strength to withstand actual use, and is easy to handle. be excellent.

In addition, the tensile strength of the nonwoven fabric is preferably 3 N/50 mm or more, more preferably 5 N/50 mm or more, in the width direction (CD direction) of the product as a direction orthogonal to one direction of the nonwoven fabric for absorbent articles, It is preferably 6 N/50 mm or more, preferably 20 N/50 mm or less, more preferably 15 N/50 mm or less, and even more preferably 12 N/50 mm or less.
That is, the nonwoven fabric for absorbent articles has a tensile strength in the MD direction greater than that in the CD direction. Such a difference in tensile strength is due to a difference in the orientation of the constituent fibers of the nonwoven fabric. Also, it is difficult to break even in actual use.

Tensile strength can be measured according to JIS P8113 using a tensile compression tester (manufactured by Shimadzu Corporation, AG-IS). When the nonwoven fabric to be measured is incorporated in a product such as an absorbent article, the absorbent article is sprayed with a cold spray to solidify the adhesive bonding the constituent members of the absorbent article. , disassembled for each component. Then, after taking out the nonwoven fabric to be measured from the product, it is cut into a size of 200 mm in the vertical direction×50 mm in the horizontal direction as a measurement sample. Using a load cell of 50 N, the distance between chucks is set to 180 mm, the measurement sample is pulled along the MD direction or the CD direction at a tensile speed of 20 mm/min, and the maximum load (N/50 mm) at breakage is recorded. Five measurement samples are prepared for each site to be measured, the maximum load is measured for each, and the arithmetic average value is taken as the tensile strength (N/50 mm) of the nonwoven fabric for absorbent articles. If it is difficult to take out or cut out a measurement sample having the above dimensions, the measurement sample is subjected to measurement with dimensions that can be cut out or taken out, or the tensile strength is calculated by converting it into a load per 25 mm. good too. Machine direction or transverse direction in the measurement of tensile strength means the longitudinal direction (MD direction) or width direction (CD direction) of the product respectively.
When a nonwoven fabric alone is to be measured, the MD direction or CD direction is confirmed by observing the orientation direction of fibers using a scanning electron microscope JCM-6000 (manufactured by JEOL Ltd.). More specifically, the nonwoven fabric is observed from one side, the direction along the orientation direction of the fibers is defined as the MD direction, and the direction orthogonal to the MD direction is defined as the CD direction.

The fibers constituting the nonwoven fabric for absorbent articles preferably have fusion points where the fibers are fused to each other. In this case, the fusion points exist three-dimensionally dispersed in the nonwoven fabric. At the fusion point between the fibers, the boundary between at least one of the fibers is unclear at the crossing point of the fibers because the resin constituting the fibers is melted by at least one of heat and pressure. The fusion point between the fibers is, for example, between the natural fiber and the first core-sheath fiber, between the first core-sheath fibers, between the first and second core-sheath fibers, or between the second core-sheath fibers. is formed in at least one place between With such a structure, it is possible to prevent the occurrence of fluffing and coming off of the fibers while exhibiting strength that can withstand actual use as a nonwoven fabric, and in this respect also, the nonwoven fabric has a good touch.
The presence or absence of fused points in a nonwoven fabric can be determined by cutting the nonwoven fabric to be measured in the thickness direction with a razor or the like to obtain a cut surface, and observing the fibers present on the cut surface with a microscope or microscope. can.
Such a nonwoven fabric is preferably an air-through nonwoven fabric, and can be easily obtained, for example, by the manufacturing method described below.

The basis weight of the first fiber layer is preferably 10 g/m ² or more, more preferably 12 g/m ² or more, from the viewpoint of improving workability and texture while reducing the manufacturing cost of the nonwoven fabric. is 25 g/m ² or less, more preferably 20 g/m ² or less.
In addition, the basis weight of the second fiber layer is preferably 6 g/m ² or more, more preferably 8 g/m ² or more, from the viewpoint of improving workability and texture while reducing the manufacturing cost of the nonwoven fabric. , preferably 20 g/m ² or less, more preferably 15 g/m ² or less.
In addition, the basis weight (total basis weight) of the entire nonwoven fabric for absorbent articles is preferably 16 g/m ² or more, more preferably 20 g/m2 or more, from the viewpoint of improving workability and texture while reducing the production cost of the nonwoven fabric. m ² or more, preferably 45 g/m ² or less, more preferably 35 g/m ² or less.

The nonwoven fabric for absorbent articles of the present invention preferably has a thickness of 0.3 mm or more, more preferably 0.5 mm or more, still more preferably 0.8 mm or more, from the viewpoint of improving the texture of the nonwoven fabric. is 5.0 mm or less, more preferably 4.0 mm or less, still more preferably 3.0 mm or less. The thickness of the nonwoven fabric for absorbent articles described above is measured using a laser displacement gauge or the like under a load of 4.9 mN/cm ² (0.5 gf/cm ² ).

From the viewpoint of improving the texture of the nonwoven fabric, the fiber diameter of the first core-sheath fibers is preferably 10 μm or more, more preferably 14 μm or more, and preferably 20 μm or less, more preferably 17 μm or less.
From the same point of view, the fiber diameter of the second core-sheath fiber is preferably 8 μm or more, more preferably 10 μm or more, and preferably 16 μm or less, more preferably 14 μm or less.
The fiber diameter described above is measured by observing the cross section of the constituent fibers of the nonwoven fabric at a magnification of 200 to 800 times using a microscope VH-8000 (manufactured by Keyence Corporation) and the razor described above. The fiber diameter is measured at 5 points when one observed fiber is approximated to a circle, and the arithmetic mean value of the 5 measured values is taken as the diameter of the fiber.

The fiber length of the first core-sheath fiber is preferably 5 mm or more, more preferably 20 mm or more, and more preferably 20 mm or more, from the viewpoint of improving curdability during nonwoven fabric production and suppressing deterioration in texture due to roughness caused by neps. It is 100 mm or less, more preferably 80 mm or less.
From the same point of view, the fiber length of the second core-sheath fiber is preferably 5 mm or more, more preferably 20 mm or more, and preferably 100 mm or less, more preferably 80 mm or less.
The fiber length described above is obtained by using a scanning electron microscope JCM-6000 (manufactured by JEOL Ltd.) to identify the layer in which each core-sheath fiber exists in the same manner as in the method for measuring the fiber density of the fiber layer described above. The constituent fibers of the layer are traced along their length and the length from one end to the other is measured. The length of five fibers is measured, and the arithmetic mean value of the five fibers is taken as the fiber length described above.

The nonwoven fabric for absorbent articles of the present invention may be composed only of natural fibers, first core-in-sheath fibers and second core-in-sheath fibers. Fibers other than the fibers may be contained. Other fibers include, for example, fibers containing the above-described thermoplastic resin, regenerated cellulose fibers such as rayon and cupra, and the like. These other fibers can be used singly or in combination of two or more. Generally, the content of other fibers in the nonwoven fabric is preferably 20% by mass or less, more preferably no other fibers.

In the above description, for convenience of explanation, a nonwoven fabric comprising only the first fiber layer and the second fiber layer was taken as an example. In addition to the layer and the second fiber layer, it may be a three or more layer structure further comprising another fiber layer. When the nonwoven fabric for absorbent articles has a structure of three or more layers, the other fiber layers are the surface of the first fiber layer on which the second fiber layer is not arranged, and the first fiber layer of the second fiber layer. It is arranged on at least one of the surfaces on which the fiber layer is not arranged. In this case, the outer surface of the nonwoven fabric for absorbent articles is composed of the first fiber layer or the second fiber layer and the other fiber layer, or is composed of the other fiber layer alone. Constituent fibers of other fiber layers include fibers containing the above-mentioned thermoplastic resin, natural fibers, regenerated cellulose fibers, and the like.

The nonwoven fabric for absorbent articles described above may be used as it is, or may be used as a constituent member of absorbent articles.

Typically, an absorbent article comprises a topsheet and a backsheet, with an absorbent body disposed between the topsheet and the backsheet, in addition to or on the topsheet or the backsheet. Instead, it can be used in a state in which a nonwoven fabric for absorbent articles is arranged.

When the nonwoven fabric for absorbent articles is used as a constituent member of absorbent articles, etc., the nonwoven fabric for absorbent articles does not touch the user's skin when using the absorbent article or when handling the absorbent article, such as taking it out of the package. It can be placed in a site that comes into direct contact. In other words, the nonwoven fabric for absorbent articles is preferably arranged on the outer surface of the absorbent article.
The outer surface of the absorbent article means the surface of the absorbent article (including the front and back) that the user can directly touch when using the absorbent article or handling the absorbent article, such as taking it out of the package. However, it means the surface side, not the inner surface that progresses in the thickness direction.

Specifically, when a nonwoven fabric for absorbent articles is used for a disposable diaper, for example, as an absorbent article, it is used as a constituent member such as a surface sheet, a side nonwoven fabric, a waist gather, a gather arranged near the groin, and an outer body. A preferred example is an exterior body.
When nonwoven fabrics for absorbent articles are used for urine leakage pads and sanitary napkins as absorbent articles, they can be used as constituent members such as surface sheets, side nonwoven fabrics, and hip guards.
When the nonwoven fabric for absorbent articles is used for urine leakage pads and sanitary napkins as absorbent articles, it can be used, for example, as a constituent member such as a surface sheet or a gather placed near the groin.

From the viewpoint of enhancing the feel and texture of the absorbent article during use by using a nonwoven fabric with less fluffing of the constituent fibers, the nonwoven fabric for absorbent articles is arranged so as to constitute the outer surface of the absorbent article. It is also preferable that the second fiber layer of the nonwoven fabric is arranged to face the outer surface of the absorbent article.
For example, when a nonwoven fabric for absorbent articles is used as the topsheet, the second fiber layer of the nonwoven fabric is preferably arranged on the skin facing side of the absorbent article or constitutes the skin facing side. . Further, for example, when a nonwoven fabric for absorbent articles is used as an outer covering, the nonwoven fabric is arranged so that the second fiber layer constitutes the non-skin facing side of the absorbent article or the non-skin facing side. is preferred.

The surface sheet used in the absorbent article is the surface facing the skin of the wearer wearing the absorbent article when the absorbent article is worn in a proper position (hereinafter also referred to as the skin-facing surface). It is the sheet that constitutes the sides. The backsheet is a sheet that constitutes the side facing away from the skin of the wearer who wears the absorbent article (hereinafter also referred to as "non-skin facing side").
As the topsheet and the backsheet used in absorbent articles, when using materials other than the nonwoven fabric for absorbent articles of the present invention, those conventionally used in absorbent articles can be used without particular limitation. As the surface sheet, for example, various liquid-permeable nonwoven fabrics, perforated films, and the like can be used. As the backsheet, a liquid-impermeable, water-repellent, or liquid-impermeable sheet can be used. For example, a resin film or a laminate of a resin film and a nonwoven fabric can be used.

Absorbent bodies used in absorbent articles comprise an absorbent core. The absorbent core is, for example, a laminate of hydrophilic fibers such as cellulose such as pulp, a mixture of hydrophilic fibers and a water-absorbing polymer, a pile of water-absorbing polymers, or between two sheets. It is composed of an absorbent sheet or the like on which a plurality of water-absorbent polymer particles are arranged, and typically contains hydrophilic fibers and a water-absorbent polymer.
The absorbent core may be covered with a corewrap sheet. As a covering mode of the core wrap sheet, for example, at least the skin-facing surface may be covered with a liquid-permeable core wrap sheet, and the entire surface including the skin-facing surface and the non-skin-facing surface is covered with the core wrap sheet. May be covered. As the core wrap sheet, for example, a thin paper made of hydrophilic fibers, a liquid-permeable nonwoven fabric, or the like can be used.

The nonwoven fabric for absorbent articles of the present invention and absorbent articles comprising the nonwoven fabric have been described above, and a preferred method for producing the nonwoven fabric for absorbent articles of the present invention will be described below. This manufacturing method preferably includes a step (air-through step) of performing an air-through treatment on a web of predetermined fibers to obtain a fiber assembly.
In addition to this, it is preferable to further employ a step of subjecting the obtained fiber assembly to calendering (calendering step).

First, a web of fibers to be subjected to air-through treatment is formed. The fiber web can be formed, for example, by a carding method using a known carding machine.
As a preferred form of the nonwoven fabric, in the case of manufacturing a multi-layer structure comprising a first fiber layer and a second fiber layer, for example, natural fibers formed by a carding method and first core-sheath fibers are mixed. and a second fiber web containing second core-sheath fibers formed by carding are laminated to form a laminate of fiber webs.
Since the content ratio of each component fiber in the first fiber web and the second fiber web and the content ratio of the fiber in the target nonwoven fabric do not substantially change before and after this step, the first fiber web and the second fiber web The content ratio of each constituent fiber in the fiber web can be set within the range described above.

By subjecting the laminate to an air-through treatment, an air-through nonwoven fabric, which is a fiber aggregate having a multi-layer structure, can be obtained. This step is a step of forming a fiber web into a nonwoven fabric, and the fiber assembly thus produced is generally called an air-through nonwoven fabric.

In the air-through step, it is preferable that the hot air blown onto the laminate of fiber webs has a temperature and an air velocity within specific ranges. Specifically, in relation to the melting point M (°C) of the resin constituting the fiber web, the temperature of the hot air blown onto the fiber web is preferably melting point M + 10°C or less, more preferably melting point M + 8°C or less, and even more preferably melting point M + 6°C. °C or less. By setting the temperature within such a range, the fibers are fused together so as to reduce fluffing of the obtained nonwoven fabric for absorbent articles while maintaining the structure of the constituent fibers as fibers, and the texture of the obtained nonwoven fabric is improved. can do well.

In addition, from the viewpoint of appropriately fusing the fibers constituting the fibrous web to allow the nonwoven fabric for absorbent articles to exhibit a strength that can withstand use, the temperature of the hot air blown onto the fibrous web is preferably set to a melting point of M-4°C. Above, more preferably melting point M−2° C. or higher, still more preferably melting point M or higher.
The temperature of the hot air mentioned above is the temperature at the outlet of the hot air. This temperature can be measured, for example, by attaching a thermocouple at or as close to the outlet as possible.

For example, when a core-sheath composite fiber containing PET (melting point: 255° C.) in the core and PE (melting point: 132° C.) in the sheath is used as the fibers constituting the fiber web, the temperature of the hot air is set to M , preferably 128° C. or higher, more preferably 130° C. or higher, and still more preferably 132° C. or higher.
The temperature of the hot air under the above conditions is preferably 142° C. or lower, more preferably 140° C. or lower, and even more preferably 138° C. or lower.

The melting point M of the resin constituting the fiber surface can be measured using a differential scanning calorimeter (DSC7000x, manufactured by Hitachi High-Tech Science Co., Ltd.). First, using a finely cut fiber sample (1 mg), thermal analysis of the sample is performed at a heating rate of 10° C./min to measure the melting peak temperature of each resin. The melting point is defined as the melting peak temperature during the first heating. If the melting point cannot be unambiguously determined by this method, the resin is defined as "a resin without a melting point". If the resin does not have a melting point, the softening point is the melting point M. Further, the melting point M is based on the resin having the lowest melting point or softening point among the resins constituting the fibrous web.

In the air-through step, the wind speed of the hot air blown to the laminate of the fiber webs is preferably 0.6 m from the viewpoint of allowing the hot air to sufficiently pass in the thickness direction of the fiber webs and facilitating the formation of fusion points between the fibers. / sec or more, more preferably 1.0 m/sec or more.
From the same point of view, the wind speed of the hot air blown onto the laminate of fiber webs is preferably 2.0 m/sec or less, more preferably 1.4 m/sec or less.
By performing the air-through process under the temperature and wind speed conditions described above, the thermoplastic resin existing on the surface of each core-sheath fiber that constitutes the fiber web is melted or softened, and the heat-sealing property is efficiently exhibited in the fiber. can randomly form regions where the fibers are fused to each other. As a result, the nonwoven fabric for absorbent articles to be produced exhibits the flexibility and good texture attributed to the air-through nonwoven fabric, and exhibits strength enough to withstand use.

From the same point of view, the conveying speed of the fiber web laminate in the air-through step is preferably 3 m/sec or more, more preferably 5 m/sec or more, and preferably 50 m/sec or less within the temperature and wind speed ranges described above. , more preferably 20 m/sec or less.

Since the laminate obtained through the above steps is a fiber assembly made into a nonwoven fabric, it may be used as it is as the nonwoven fabric for absorbent articles of the present invention. This nonwoven fabric for absorbent articles is an air-through nonwoven fabric.

From the viewpoint of easily obtaining a thin nonwoven fabric for absorbent articles in which a predetermined fiber density is easily achieved efficiently and the fluffing of the fibers is further reduced, the fiber aggregate, which is a laminate that has undergone an air-through process, is: A further calendering treatment is preferably carried out (calendering step).

The calendering step in this step is a method of introducing and pressurizing a fiber assembly between a pair of rolls. This step may be performed only once, or may be performed multiple times as necessary. The temperature in the calendering step may be unheated (for example, room temperature), heated, or a combination thereof.

The pressurization conditions in the calendering step are preferably 78.4 N/cm (8 kgf/cm) or more in terms of linear pressure, from the viewpoint of easily obtaining a nonwoven fabric for absorbent articles having a high fiber density and reduced fiber fluffing. , more preferably 98 N/cm (10 kgf/cm) or more.
In addition, from the viewpoint of improving the texture of the obtained nonwoven fabric for absorbent articles while maintaining the fiber shape in which the boundaries between the constituent fibers are clear without making the fiber aggregate into a film, Pressurization conditions are preferably 686 N/cm (70 kgf/cm) or less, more preferably 294 N/cm (30 kgf/cm) or less, in terms of linear pressure.

The pressurization time in the calendering process can be appropriately set as long as the fiber shape of the fibers constituting the fiber assembly is maintained. It can be 0.01 seconds or more, more preferably 0.04 seconds or more, preferably 0.1 seconds or less, more preferably 0.08 seconds or less.

When the calendering process is performed by multiple pressure treatments, it is preferable that the second pressure treatment be performed with a lower degree of pressure than the first pressure treatment. As a method for reducing the degree of pressure application, for example, the gap between the pair of rolls in the second pressing process is made wider than the gap between the pair of rolls in the first pressing process, so that the external force applied to the fiber assembly is reduced. can be lowered. By configuring in this way, a nonwoven fabric having high flexibility while reducing fluffing can be efficiently obtained.

The pair of rolls used in the calendering process can be made of a non-elastic material such as metal or an elastic material such as rubber or resin. As for the pair of rolls, for example, one roll may be a metal roll and the other roll may be an elastic roll. Each of these rolls may independently have a smooth peripheral surface, or may have an uneven peripheral surface.

Examples of elastic materials include elastically deformable elastic resins such as hard rubber, silicon rubber, urethane rubber, acrylonitrile-butadiene rubber (NBR), and ethylene-propylene-diene rubber (EPDM). These resins preferably have a type D hardness of 20 or more, more preferably 70 or more, and preferably 100 or less, more preferably 95 or less, measured according to JIS K6253. The type D hardness is one index of hardness, and the higher the value, the higher the hardness.

By performing the calendering process under the above conditions, the fiber aggregate can be compressed in the thickness direction to easily obtain a nonwoven fabric for absorbent articles in which a predetermined fiber density is easily achieved. The nonwoven fabric for absorbent articles obtained by the above-described method is an air-through nonwoven fabric even after the calendering process.

Through the above steps, the nonwoven fabric for absorbent articles of the present invention can be obtained. This nonwoven fabric for absorbent articles is preferably incorporated as a constituent member of absorbent articles in subsequent steps.
When the nonwoven fabric for absorbent articles is used as a constituent material of absorbent articles, the nonwoven fabric for absorbent articles produced by the above-described method is used as one of the constituent materials in any of the processes for producing absorbent articles. , performing various operations such as cutting the nonwoven fabric for absorbent articles, and laminating or joining the nonwoven fabric for absorbent articles and other constituent materials (for example, an absorbent body, a sheet, etc.) constituting the absorbent article. One or more of the steps can be included to produce the intended absorbent article.

Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments.

Regarding the embodiment of the present invention described above, the following nonwoven fabric for absorbent articles and absorbent articles including the same are further disclosed.
<1>
A nonwoven fabric for absorbent articles comprising a first fiber layer and a second fiber layer arranged adjacent to the first fiber layer,
The nonwoven fabric contains 0.5% by mass or more and 3.0% by mass or less of natural fibers,
As fibers constituting the first fiber layer, natural fibers and first heat-fusible core-sheath composite fibers having a fineness of 1.5 dtex or more and 3.0 dtex or less are included,
A nonwoven fabric for an absorbent article, comprising a second heat-fusible core-sheath composite fiber having a fineness of 0.5 dtex or more and less than 1.5 dtex as fibers constituting the second fiber layer.

<2>
The nonwoven fabric for absorbent articles according to <1>, wherein the natural fibers are cotton fibers.
<3>
The absorption according to <1> or <2> above, wherein the content of the natural fiber is 0.6% by mass or more and 2.0% by mass or less, preferably 0.7% by mass or more and 1.5% by mass or less Non-woven fabric for sexual goods.
<4>
Any one of <1> to <3> above, wherein the first heat-fusible core-sheath composite fiber has a fineness of 1.6 dtex or more and 2.6 dtex or less, preferably 1.7 dtex or more and 2.4 dtex or less. Nonwoven fabric for absorbent articles according to.
<5>
Any one of <1> to <4> above, wherein the second heat-fusible core-sheath composite fiber has a fineness of 0.6 dtex or more and 1.4 dtex or less, preferably 0.7 dtex or more and 1.3 dtex or less. Nonwoven fabric for absorbent articles according to.

<6>
The content of the first heat-fusible core-sheath composite fiber in the first fiber layer is 90.0% by mass or more and 99.5% by mass or less, preferably 95.0% by mass or more and 99.0% by mass. The nonwoven fabric for absorbent articles according to any one of <1> to <5>, more preferably 97.0% by mass or more and 99.0% by mass or less.
<7>
The content of the natural fibers in the first fiber layer is 0.5% by mass or more and 3.0% by mass or less, preferably 0.8% by mass or more and 2.8% by mass or less, more preferably 1.0% by mass. % or more and 2.5% by mass or less, the nonwoven fabric for absorbent articles according to any one of <1> to <6>.
<8>
The content of the second heat-fusible core-sheath composite fiber in the second fiber layer is 90.0% by mass or more and 100% by mass or less, preferably 95.0% by mass or more and 100% by mass or less, more preferably is 98.0% by mass or more and 100% by mass or less, the nonwoven fabric for absorbent articles according to any one of <1> to <7>.

<9>
The fiber density of the first fiber layer is 20 fibers/mm ² or more and 80 fibers/mm ² or less, preferably 25 fibers/mm ² or more and 70 fibers/mm ² or less, more preferably 30 fibers/mm ² or more and 65 fibers/mm 2 or more. mm ² or less, the nonwoven fabric for absorbent articles according to any one of <1> to <8>.
<10>
The fiber density of the second fiber layer is 30 fibers/mm ² or more and 200 fibers/mm ² or less, preferably 40 fibers/mm ² or more and 150 fibers/mm ² or less, more preferably 50 fibers/mm ² or more and 130 fibers/mm 2 or more. mm ² or less, the nonwoven fabric for absorbent articles according to any one of <1> to <9>.
<11>
Any one of <1> to <10> above, wherein the basis weight of the first fiber layer is 10 g/m ² or more and 25 g/m ² or less, more preferably 12 g/m ² or more and 20 g/m ² or less A nonwoven fabric for absorbent articles as described.

<12>
Any one of <1> to <11> above, wherein the basis weight of the second fiber layer is 6 g/m ² or more and 20 g/m ² or less, preferably 8 g/m ² or more and 15 g/m ² or less. nonwoven fabric for absorbent articles.
<13>
The absorbent article according to any one of <1> to <12> above, wherein the total basis weight is 16 g/m ² or more and 45 g/m ² or less, preferably 20 g/m ² or more and 35 g/m ² or less. non-woven fabric.
<14>
The thickness under a load of 4.9 mN/cm ² (0.5 gf/cm ² ) is 0.3 mm or more and 5.0 mm or less, preferably 0.5 mm or more and 4.0 mm or less, more preferably 0.8 mm or more and 3.0 mm. The nonwoven fabric for absorbent articles according to any one of <1> to <13>, wherein:

<15>
The absorbent article according to any one of <1> to <14>, wherein the first heat-fusible core-sheath composite fiber has a fiber diameter of 10 μm or more and 20 μm or less, preferably 14 μm or more and 17 μm or less. non-woven fabric.
<16>
The absorbent article according to any one of <1> to <15>, wherein the second heat-fusible core-sheath composite fiber has a fiber diameter of 8 μm or more and 16 μm or less, preferably 10 μm or more and 14 μm or less. non-woven fabric.
<17>
The fiber length of the first heat-fusible core-in-sheath composite fiber or the second heat-fusible core-in-sheath composite fiber is 5 mm or more and 100 mm or less, preferably 20 mm or more and 80 mm or less, above <1> to <16> The nonwoven fabric for absorbent articles according to any one of above.
<18>
The core/sheath combination of the first heat-fusible core-sheath composite fiber or the second heat-fusible core-sheath composite fiber is at least one selected from PET/PP, PET/PE and PE/PP. The nonwoven fabric for absorbent articles according to any one of <1> to <17> above.

<19>
The above <1> to <18>, wherein the first heat-fusible core-sheath composite fiber or the second heat-fusible core-sheath composite fiber is at least one selected from a concentric type and an eccentric type. The nonwoven fabric for absorbent articles according to any one of.
<20>
The nonwoven fabric for absorbent articles according to any one of <1> to <19>, which is an air-through nonwoven fabric.
<21>
An absorbent article comprising the nonwoven fabric for absorbent articles according to any one of <1> to <20>.
<22>
The absorbent article according to <21>, wherein the second fiber layer is arranged to face the outer surface of the absorbent article.

<23>
The method for producing a nonwoven fabric for absorbent articles according to any one of <1> to <20>,
Forming a first fiber web containing the first heat-fusible core-sheath composite fiber and the natural fiber in a mixed state and a second fiber web containing the second heat-fusible core-sheath composite fiber,
The first fiber web and the second fiber web are laminated to form a laminate, and after that,
A method for producing a nonwoven fabric for absorbent articles, wherein the laminate is subjected to an air-through treatment.
<24>
The manufacturing method according to <23>, wherein the layered product subjected to the air-through treatment is further subjected to a calendering treatment.

<25>
In the air-through treatment, the temperature of hot air blown to the laminate is 128° C. or higher and 142° C. or lower, preferably 130° C. or higher and 140° C. or lower, more preferably 132° C. or higher and 138° C. or lower. > The manufacturing method described in .
<26>
In the air-through treatment, the speed of the hot air blown onto the laminate is 0.6 m/sec or more and 2.0 m/sec or less, more preferably 1.0 m/sec or more and 1.4 m/sec or less, the above <23>. The production method according to any one of <25>.
<27>
<23> to <26>, wherein the conveying speed of the laminate in the air-through treatment is 3 m/sec or more and 50 m/sec or less, more preferably 5 m/sec or more and 20 m/sec or less. Production method.

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the scope of the invention is not limited to such examples. In the table below, columns indicated by "-" indicate non-containment or non-implementation. In addition, the MD direction of the nonwoven fabric in the following evaluation means the direction along the orientation direction of the fibers measured by the same method as the measurement of the tensile strength described above. The CD direction is a direction perpendicular to the MD direction.

[Examples 1 to 3]
As the first core-sheath fiber, a heat-fusible core-sheath composite fiber having a fineness of 2.0 dtex, a core of PET (50% by mass) and a sheath of PE (50% by mass) was used. The first core-sheath fibers and cotton fibers as natural fibers were mixed at the mass ratio shown in Table 1 below to obtain a first fiber web. Each of the first fiber webs had a basis weight of 15 g/cm ² .
Apart from this, as the second core-sheath fiber, a heat-fusible core-sheath composite fiber having a fineness of 1.2 dtex, a core of PET (50% by mass) and a sheath of PE (50% by mass) was used to form a second fiber web consisting of an aggregate of these fibers. Each of the second fiber webs had a basis weight of 10 g/cm ² .

Then, the laminate obtained by laminating the first fiber web and the second fiber web was subjected to an air-through treatment under the conditions shown in Table 1 below to form a nonwoven fabric for absorbent articles as a fiber assembly (basis weight: 25 g/cm ² ). got This nonwoven fabric had a two-layer structure consisting of a first fiber layer derived from a first fiber web and a second fiber layer derived from a second fiber web, and fusion points were formed between the fibers. .

[Example 4]
After the air-through treatment was performed under the same configuration and under the same conditions as in Example 3, the resulting fiber assembly was further subjected to a calendering treatment to obtain the intended nonwoven fabric for absorbent articles. In the calendering step, both are passed between a resin roll and a metal roll under unheated conditions (room temperature) to perform a first pressurization, and then further between the resin roll and the metal roll. A second pressurization was applied by passing between. The linear pressure in the first pressurization was set to 255 N/cm, and the linear pressure in the second pressurization was set to 115 N/cm. A hard rubber roll having a D hardness of 90 degrees was used as the resin roll. This nonwoven fabric had a two-layer structure consisting of a first fiber layer derived from a first fiber web and a second fiber layer derived from a second fiber web, and fusion points were formed between the fibers. .

[Comparative Example 1]
As the second core-sheath fiber, a heat-fusible core-sheath composite fiber having a fineness of 1.7 dtex, a core of PET (50% by mass) and a sheath of PE (50% by mass) was used. , the intended nonwoven fabric for absorbent articles was obtained under the same configuration and conditions as in Example 2.

[Comparative Example 2]
The target nonwoven fabric for absorbent articles was obtained in the same configuration and under the same conditions as in Example 1, except that the first fiber web contained no natural fibers and only the first core-sheath fibers were used.

[Comparative Examples 3 to 5]
The target nonwoven fabric for absorbent articles was produced under the same conditions as in Example 1, except that the contents of the first core-sheath fibers and the natural fibers in the first fiber web were changed as shown in Table 1 below. Obtained.

[Measurement of thickness of nonwoven fabric for absorbent articles]
The thicknesses of the nonwoven fabrics for absorbent articles of Examples and Comparative Examples were measured. The thickness is measured at 5 or more locations using a laser displacement meter while a load of 4.9 mN/cm ² is applied to the nonwoven fabric for absorbent articles to be measured, and the arithmetic average value thereof is taken as the thickness (mm ). Table 1 shows the results.

[Measurement of fiber density in each fiber layer]
For the nonwoven fabrics for absorbent articles of Examples and Comparative Examples, the fiber layers were specified by the method described above, and the abundance density (fibers/mm ² ) of the constituent fibers in each fiber layer was measured. Table 1 shows the results.

[Measurement of adhesive strength]
For the nonwoven fabrics for absorbent articles of Examples and Comparative Examples, the adhesive strength between the first fiber layer side and other members was measured by the following method.
For the nonwoven fabric to be measured, using a razor (product number FAS-10, manufactured by Feather Safety Razor Co., Ltd.), two areas of 10 cm × 5 cm in plan view are cut out over the entire thickness direction to obtain two test pieces. . Next, a hot melt adhesive with a basis weight of 6 g/m2 (manufactured by Henkel Co., Ltd., rubber hot melt) is applied to a 5 cm × 5 cm area on one end side of the test piece in the longitudinal direction on one side of one test piece. was applied, attached to another test piece, a weight of 2 kg was placed thereon, and left to stand for 5 minutes to obtain a measurement sample. The two test pieces are attached to each other so that the first fiber layers of the nonwoven fabric are present, and the first fiber layers face each other. Next, each end of the measurement sample on which the two test pieces are not bonded is fixed between chucks of a Tensilon universal testing machine ("RTG1310" manufactured by A&D Co., Ltd.). The distance between chucks shall be 50 mm. Next, the chuck is moved along the 180° direction at a speed of 300 mm/min to separate the two test pieces. Obtain the maximum value of tensile strength observed at this time. This measurement is repeated three times, and the arithmetic average value thereof is taken as the adhesive strength. Table 1 shows the results.

[Measurement of tensile strength]
For the nonwoven fabrics for absorbent articles of Examples and Comparative Examples, each tensile strength in the MD direction and the CD direction was measured by the method described above. Table 1 shows the results.

[Evaluation of fluffiness of constituent fibers]
For the nonwoven fabrics for absorbent articles of Examples and Comparative Examples, the fluffiness of fibers was measured by the following method.
First, a disc (diameter 70 mm, 350 g) is mounted at a position where its center is shifted from the rotation axis of the testing machine by 20 mm. The surface of this disc is covered with urethane foam (a urethane foam manufactured by Innoatec Co., Ltd., trade name: Moltofilter MF-30 type, thickness 5 mm, surface friction coefficient 0.508).
Next, the nonwoven fabric to be measured is fixed on the table of the tester, the disk is placed on the nonwoven fabric, and the main surface of the disk and the surface of the nonwoven fabric on which the second fiber layer is present are in contact. , rotate the disk. At this time, the load applied to the nonwoven fabric is only the weight of the disk itself. This rotation was performed for 10 cycles, with one cycle consisting of three clockwise rotations and three counterclockwise rotations. The rotation time was 3 seconds per rotation.

The nonwoven fabric was cut along the MD direction, and the cross section of the nonwoven fabric in the CD direction was observed with a digital microscope VHX1000 (trade name) manufactured by Keyence Corporation at a magnification of 40 and evaluated. After that, one end of the fiber end is separated from the outer surface of the second fiber layer, and the fiber is visually cut off with scissors at the boundary with the outer surface of the second fiber layer, and the length is 2 mm when stretched in a straight line. The above fibers are called fluff. The fluffing was evaluated by calculating the arithmetic mean value of the values measured at 10 points every 10 mm in the MD direction and evaluating it according to the following criteria.

<Evaluation criteria for less fluff>
A: The number of fluffs (fibers) from the second fiber layer is 0, which is very excellent.
B: The number of fluffs (fibers) from the second fiber layer is 1 or more and less than 2, which is excellent.
C: The number of fluffs (fibers) from the second fiber layer is 2 or more and less than 3, and there is no problem.
D: The number of fluffs (fibers) from the second fiber layer is 3 or more, which is bad.

[Evaluation of softness and smoothness of nonwoven fabric]
The surface of the nonwoven fabric was moved with the palm along the MD direction, and the softness and smoothness of the texture were evaluated based on the touch. These evaluations were performed by three expert panelists, and evaluation criteria were evaluated according to the following criteria, with the texture of the outer layer of Mary's Pants Big Size (manufactured by Kao Corporation, 2020, sold in Japan) as 3 points. A value was calculated by rounding the arithmetic mean of the scores of the panelists to the nearest whole number. The higher this value, the better the feel of the nonwoven fabric. Table 1 shows the results.

<Evaluation criteria for softness>
5 points: Extremely superior in softness to the evaluation standard product.
4 points: Superior in softness to the evaluation standard product.
3 points: The softness is equivalent to that of the evaluation standard product.
2 points: Poorer in softness than the evaluation standard product.
1 point: It is clearly harder than the evaluation standard product and does not perceive softness.
<Evaluation Criteria for Smoothness>
5 points: Extremely superior in smoothness to the evaluation standard product.
4 points: Better smoothness than the evaluation standard product.
3 points: The smoothness is equivalent to that of the evaluation standard product.
2 points: Inferior in smoothness to evaluation standard product.
1 point: The smoothness is clearly worse than the evaluation standard product, and the smoothness is not perceived.

As shown in Table 1, it can be seen that the nonwoven fabrics for absorbent articles of each example have less fluffing of the constituent fibers and are superior in texture such as softness and smoothness compared to those of the comparative examples. .

Claims (6)

A nonwoven fabric for absorbent articles comprising a first fiber layer and a second fiber layer arranged adjacent to the first fiber layer,
The nonwoven fabric contains 0.5% by mass or more and 3.0% by mass or less of natural fibers,
As fibers constituting the first fiber layer, the natural fiber and the first heat-fusible core-sheath composite fiber having a fineness of 1.5 dtex or more and 3.0 dtex or less are included,
A nonwoven fabric for an absorbent article, comprising a second heat-fusible core-sheath composite fiber having a fineness of 0.5 dtex or more and less than 1.5 dtex as fibers constituting the second fiber layer. The nonwoven fabric for absorbent articles according to claim 1, wherein said natural fibers are cotton fibers. The nonwoven fabric for absorbent articles according to claim 1 or 2, wherein the first fiber layer contains 0.5% by mass or more and 3.0% by mass or less of the natural fiber. The nonwoven fabric for absorbent articles according to any one of claims 1 to 3, which is an air-through nonwoven fabric. An absorbent article comprising the nonwoven fabric for absorbent articles according to any one of claims 1 to 4. 6. The absorbent article according to claim 5, wherein said second fiber layer is arranged to face the outer surface side of said absorbent article.