JP2022158707A - Nonwoven fabric for absorbent article and absorbent article including the same - Google Patents

Abstract

To provide a nonwoven fabric achieving both durable hydrophilicity and dryness, and an absorbent article including the nonwoven fabric.SOLUTION: A nonwoven fabric 10 includes a plurality of first projection rows 11 extending in one direction. Each first projection row 11 includes large projections 11ab, and small projections 11as having a thickness and/or an area smaller than that of the large projections 11ab. The large projections 11ab and the small projections 11as are alternately aligned in one direction and a direction orthogonal thereto. The hydrophilicity of the small projections 11as is higher than that of the large projections 11ab. The nonwoven fabric 10 contains the following (A) component and (B) component: (A) polyorganosiloxane; and (B) anionic surfactant represented by the following formula (1).SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a nonwoven fabric for absorbent articles and absorbent articles having the same.

Absorbent articles such as sanitary napkins have a topsheet that contacts the wearer's skin when worn. From the viewpoint of maintaining good permeability to liquids such as urine and menstrual blood and reducing stickiness caused by the liquids, it is desirable that the surface sheet be excellent in durable hydrophilicity. Fiber treatment agents for imparting such durable hydrophilicity to sheets are known.
For example, Patent Document 1 discloses one or more of a (poly)amine cationized product, an ester, a dialkylsulfosuccinate salt, an alkylphosphate salt, a trialkylglycine derivative and an (alkylamide group-containing alkyl)dialkylglycine derivative. A fiber treatment agent is described which contains both and a predetermined amount of a polyoxyalkylene-modified silicone.

In addition, the present applicant has previously produced a nonwoven fabric using heat-fusible fibers to which a fiber treatment agent containing polyorganosiloxane, an alkyl phosphate ester, and an anionic surfactant represented by a specific chemical formula is adhered. proposed (Patent Document 2).

Japanese Patent Application Laid-Open No. 2007-247128 JP 2014-224338 A

However, if the durable hydrophilicity of the nonwoven fabric is improved, the surface of the nonwoven fabric tends to be left with liquid residue, which may reduce the dryness. In particular, it is desirable that the nonwoven fabric used for the topsheet of the absorbent article has an excellent balance between durable hydrophilicity and dryness from the viewpoint of maintaining a good wearing feeling of the absorbent article.
Patent Literature 1 and Patent Literature 2 do not disclose a technique for achieving both durable hydrophilicity and dryness in a nonwoven fabric.

Accordingly, an object of the present invention is to provide a nonwoven fabric for absorbent articles that achieves both durable hydrophilicity and dryness, and an absorbent article comprising the same.

（式中、Ｚはエステル基、アミド基、アミン基、ポリオキシアルキレン基、エーテル基又は２重結合を含んでいてもよい、炭素数１～１２の直鎖又は分岐鎖の炭化水素基を表わし、Ｒ₁及びＲ₂はそれぞれ独立に、エステル基、アミド基、ポリオキシアルキレン基、エーテル基又は２重結合を含んでいてもよい、炭素数２～１６の直鎖又は分岐鎖のアルキル基を表わし、Ｘは―ＳＯ₃Ｍ、―ＯＳＯ₃Ｍ又は―ＣＯＯＭを表わし、ＭはＨ、Ｎａ、Ｋ、Ｍｇ、Ｃａ又はアンモニウムを表わす。） TECHNICAL FIELD The present invention relates to a nonwoven fabric for absorbent articles having a plurality of first projection rows extending in one direction.
It is preferable that the first projection row includes a large projection and a small projection having a smaller thickness and/or area than the large projection.
It is preferable that the large protrusions and the small protrusions are alternately arranged in the one direction and in a direction orthogonal to the one direction.
Preferably, the hydrophilicity of the small protrusions is higher than that of the large protrusions.
The nonwoven fabric preferably contains the following components (A) and (B).
(A) polyorganosiloxane (B) an anionic surfactant represented by the following formula (1)

(Wherein, Z represents an ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group, or a straight or branched hydrocarbon group having 1 to 12 carbon atoms, which may contain a double bond. , R ₁ and R ₂ each independently represent an ester group, an amide group, a polyoxyalkylene group, an ether group or a straight or branched alkyl group having 2 to 16 carbon atoms which may contain a double bond. X represents -SO ₃ M, -OSO ₃ M or -COOM, and M represents H, Na, K, Mg, Ca or ammonium.)

The present invention also relates to absorbent articles comprising the nonwoven fabric for absorbent articles.

ADVANTAGE OF THE INVENTION According to this invention, the nonwoven fabric for absorbent articles which made durable hydrophilicity and dryness compatible, and an absorbent article provided with the same can be provided.

FIG. 1 is a plan view showing one embodiment of the nonwoven fabric of the present invention. 2 is an enlarged view of a main part in FIG. 1. FIG. 3(a) is a cross-sectional view taken along line II-II in FIG. 2, and FIG. 3(b) is a cross-sectional view taken along line VV in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on its preferred embodiments with reference to the drawings. 1 to 3 show one embodiment of the nonwoven fabric of the present invention.
As shown in FIG. 1, the nonwoven fabric 10 for absorbent articles of the present embodiment (hereinafter also simply referred to as "nonwoven fabric") has a first projection row 11 extending along one direction (X direction) in plan view. have multiple In addition to the first row of protrusions 11 , the nonwoven fabric 10 includes a second row of protrusions 12 adjacent to the first row of protrusions 11 and a third row of protrusions adjacent to the first row of protrusions 11 . and a row of protrusions 13 . The first row of projections 11, the second row of projections 12, and the third row of projections 13 extend along one common direction (the X direction). Such a nonwoven fabric 10 has a longitudinal direction X that coincides with the extending directions of the first row of protrusions 11, the second row of protrusions 12, and the third row of protrusions 13, and a lateral direction Y that is orthogonal to the longitudinal direction X. have.

Each of the first row of projections 11, the second row of projections 12, and the third row of projections 13 is fixed by a pressed portion obtained by fusing or compacting the constituent fibers of the nonwoven fabric 10 and compressing them in the sheet thickness direction. It is demarcated by portions 15g, 15h, 15m and 15n, and has a greater thickness than each fixing portion 15g, 15h, 15m and 15n. The heights of the protrusions forming the first row of protrusions 11, the second row of protrusions 12, and the third row of protrusions 13 are all higher than the heights of the fixed portions 15g, 15h, 15m, and 15n, which will be described later. is.

The first protrusion row 11 is formed by arranging a plurality of first protrusions 11a in a row along the longitudinal direction X. As shown in FIG. The first convex portion row 11 includes a large convex portion 11ab and a small convex portion 11as as the first convex portions 11a. The small protrusion 11as has a smaller thickness and/or area than the large protrusion 11ab. The small protrusions 11as of the present embodiment are smaller in both thickness and area than the large protrusions 11ab.

In the first protrusion row 11, a plurality of large protrusions 11ab and small protrusions 11as are alternately arranged in a row along the longitudinal direction X. As shown in FIG. In this first convex portion row 11, the first convex portions 11a (large convex portion 11ab, small convex portion 11as) adjacent to each other in the longitudinal direction X are connected without being separated by the compressed portion (fixed portion).
In the nonwoven fabric 10 of the present embodiment, the large convex portions 11ab and the small convex portions 11as are formed between the first convex portion rows 11 adjacent to each other in the lateral direction Y via the second convex portion row 12 or the third convex portion row 13. , are alternately arranged in the horizontal direction Y. That is, in the nonwoven fabric 10, the large protrusions 11ab and the small protrusions 11as are alternately arranged in the vertical direction X and the horizontal direction Y, respectively. Such a pattern in which a plurality of protrusions 11ab and 11as having different areas are arranged in the planar direction is also called a "large and small protrusion pattern".

The first row of protrusions 11 has a ridge-like structure whose length along the horizontal direction Y increases and decreases periodically, and the apex of the ridge-like structure forms a continuous ridge line L1 along the vertical direction X. is doing. In this embodiment, the ridge line L1 is formed to connect the line segments of the ridge lines of the large convex portion 11ab and the small convex portion 11as, and extends linearly along the longitudinal direction X. As shown in FIG.
Further, the first convex portion row 11, more specifically, the large convex portion 11ab and the small convex portion 11as have a symmetrical structure with the ridge line L1 as the axis of symmetry. Such "a symmetrical structure with respect to the ridgeline L1 as an axis of symmetry" does not require strict geometric symmetry because the nonwoven fabric has flexibility.

In the nonwoven fabric 10 of the present embodiment, the constituent fibers of the nonwoven fabric 10 are fused or slanted in opposite directions with respect to the longitudinal direction X as the fixed portions 15 composed of compressed portions that are compressed without being fused. , a first fixing portion row 15A and a second fixing portion row 15B. In the nonwoven fabric 10, a plurality of first fixed portion rows 15A are arranged at regular intervals and extend so as to intersect the longitudinal direction X. As shown in FIG. The first fixed portion rows 15A are parallel to each other. A plurality of second fixing portion rows 15B are arranged at regular intervals, and extend so as to intersect the vertical direction X and the extending direction of the first fixing portion rows 15A. In the first convex portion row 11, each of the adjacent first fixing portion rows 15A and the adjacent second fixing portion rows 15B alternately has portions with wide intervals and portions with narrow intervals.

In the first fixing portion row 15A shown in FIG. 1, linear first fixing portions 15g and linear second fixing portions 15h shorter than the first fixing portions 15g are alternately arranged in series. The first fixed portion row 15A is a discontinuous line in which the first fixed portion 15g and the second fixed portion 15h that are adjacent in one fixed portion row are separated from each other. In the second fixing portion row 15B shown in the figure, linear third fixing portions 15m and linear fourth fixing portions 15n shorter than the third fixing portions 15m are alternately arranged in series. there is The second fixed portion row 15B is a discontinuous line in which the third fixed portion 15m and the fourth fixed portion 15n adjacent to each other in one fixed portion row are separated from each other. The fixed portions 15g, 15h, 15m, and 15n can be formed by subjecting one side of the nonwoven fabric 10 to a pressing process such as embossing.

The large convex portion 11ab is surrounded by two first fixing portions 15g in the adjacent first fixing portion row 15A and two third fixing portions 15m in the adjacent second fixing portion row 15B. formed. The large convex portion 11ab of the present embodiment is larger in thickness and area than the middle convex portion 14 described later.
The small convex portion 11as is surrounded by two second fixing portions 15h in the adjacent first fixing portion row 15A and two fourth fixing portions 15n in the adjacent second fixing portion row 15B, and has a diamond shape. formed. As will be described later, recessed portions 17 having the smallest thickness than other portions of the nonwoven fabric 10 are formed in the portions where the fixed portions 15g, 15h, 15m, and 15n are present. The small convex portion 11as of the present embodiment has a smaller thickness and area than the medium convex portion 14 to be described later.

In the second protrusion row 12 of the present embodiment, a plurality of second protrusions 12a are arranged along the longitudinal direction X in a row. The second convex portion row 12 includes two central convex portions 14a and 14b as the second convex portion 12a (see FIG. 1). Specifically, a central convex portion 14a surrounded by two first fixing portions 15g in adjacent first fixing portion rows 15A and two fourth fixing portions 15n in adjacent second fixing portion rows 15B, It includes a central convex portion 14b surrounded by two second fixing portions 15h in adjacent first fixing portion rows 15A and two third fixing portions 15m in adjacent second fixing portion rows 15B. Both of these central convex portions 14a and 14b are formed in the shape of a parallelogram. In this second convex portion row 12, a plurality of central convex portions 14a and central convex portions 14b are arranged alternately in a row along the longitudinal direction X. As shown in FIG. In this second convex portion row 12, the second convex portions 12a (central convex portion 14a, central convex portion 14b) adjacent to each other in the longitudinal direction X are connected without being separated by the compressed portion (fixed portion).
The second row of protrusions 12 of this embodiment is adjacent to the first row of protrusions 11 via respective fixing portions 15g, 15h, 15m, and 15n, and periodically meanders so as to have amplitude in the horizontal direction Y. are arranged as follows. The second convex portion row 12 in this embodiment has a ridgeline L2 formed so as to connect a row of line segments of each ridgeline in the second convex portion 12a. The second convex portion row 12 periodically meanders along the arrangement position of the second convex portion 12a so as to have an amplitude in the horizontal direction Y, and the ridge line L2, like the second convex portion row 12, It meanders periodically so as to have an amplitude in the Y direction.

The third convex portion row 13 of the present embodiment is arranged at a position symmetrical to the second convex portion row 12 with the ridge line L1 as the axis of symmetry. The third convex portion row 13 has a shape symmetrical with the second convex portion row 12 with the ridgeline L1 as the axis of symmetry. The third protrusion row 13 shown in FIG. 1 has a shape in which a plurality of third protrusions 13a are arranged in a row along the longitudinal direction X. As shown in FIG. The third convex portion row 13 includes two middle convex portions 14c and 14d as the third convex portion 13a (see FIG. 1). Specifically, a central convex portion 14c surrounded by two second fixing portions 15h in adjacent first fixing portion rows 15A and two third fixing portions 15m in adjacent second fixing portion rows 15B, and , two first fixing portions 15g in adjacent first fixing portion rows 15A and two fourth fixing portions 15n in adjacent second fixing portion rows 15B. Both of these central convex portions 14c and 14d are formed in the shape of a parallelogram. In the third convex portion row 13, a plurality of central convex portions 14c and central convex portions 14d are arranged alternately in a row along the longitudinal direction X. As shown in FIG. In the third protrusion row 13, the third protrusions 13a (middle protrusions 14c and 14d) adjacent to each other in the longitudinal direction X are connected without being separated by the compressed portion (fixed portion).
The third row of protrusions 13 is adjacent to the first row of protrusions 11 via 15g, 15h, 15m, and 15n, and is arranged to meander periodically so as to have amplitude in the horizontal direction Y. . The third convex portion row 13 in the present embodiment has a ridgeline L3 formed so as to connect a row of line segments of each ridgeline in the third convex portion 13a. The third protrusion row 13 periodically meanders so as to have amplitude in the horizontal direction Y along the arrangement position of the third protrusion 13a. The ridgeline L3, similarly to the third row of protrusions 13, periodically meanders so as to have amplitude in the horizontal direction Y. As shown in FIG.

Each of the second convex portions 12a forming the second convex portion row 12 and the third convex portions 13a forming the third convex portion row 13 serves as the middle convex portion 14 having a smaller thickness and area than the large convex portion 11ab. ing. As described above, the third convex portion row 13 has a shape symmetrical with the second convex portion row 12 with the ridge line L1 as the axis of symmetry. , the central convex portions 14 having the same position in the vertical direction X are symmetrical with each other with the ridgeline L1 as the axis of symmetry.
In the second convex portion row 12, the second convex portions 12a (central convex portions 14a and 14b) adjacent to each other in the vertical direction X pass between the central convex portions 14a and 14b and extend along the lateral direction Y. It is symmetrical with respect to the line L4.
In the third convex portion row 13, the third convex portions 13a (central convex portions 14c and 14d) adjacent to each other in the vertical direction X are imaginary extending along the lateral direction Y and passing between the central convex portions 14c and 14d. It is symmetrical with respect to the line L4.
In the present embodiment, the second convex portion row 12 and the third convex portion row 13 are arranged between the central convex portions 14 adjacent to each other in the longitudinal direction X (between the central convex portions 14a and 14b and between the central convex portions 14c). and the central convex portion 14d) and extends along the lateral direction Y.

In the nonwoven fabric 10 of the present embodiment, each of the second protrusion row 12 and the third protrusion row 13 is positioned between the first protrusion rows 11 . Specifically, as shown in FIG. 1 , in a plan view of the nonwoven fabric 10, when viewed along the lateral direction Y, the first convex row 11, the second convex row 12, the first convex row 11, and the The third convex row 13 forms a repeating unit arranged in this order.

In the nonwoven fabric 10, the hydrophilicity of the small protrusions 11as is higher than that of the large protrusions 11ab. In the nonwoven fabric 10 of the present embodiment, the hydrophilicity of the small protrusions 11as is higher than that of the medium protrusions 14, and the hydrophilicity of the medium protrusions 14 is higher than that of the large protrusions 11ab. That is, the following magnitude relationship is established for the degree of hydrophilicity.
Small convex portion 11as>Medium convex portion 14>Large convex portion 11ab
The degree of hydrophilicity can be measured using the "contact angle with water of the constituent fibers" in each convex portion. The smaller the contact angle, the higher the hydrophilicity (lower hydrophobicity) of the projections containing the constituent fibers, and the greater the contact angle, the lower the hydrophilicity (hydrophobicity) of the projections containing the constituent fibers. high).

<Method for measuring contact angle with water>
A fiber is taken out from the surface of the projection to be measured, and the contact angle of water with respect to the fiber is measured. Use scissors and tweezers to remove the fibers. In addition, the fiber take-out portion of the convex portion to be measured is the top portion of the convex portion. Here, the apex of the projection means an area surrounded by a virtual circle with a radius of 1.5 mm centering on the apex of the projection when the projection is viewed from above. As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Deionized water is used for contact angle measurements. The amount of liquid ejected from an ink-jet type water droplet ejector (Cluster Technology Co., Ltd., pulse injector CTC-25 with an ejector hole diameter of 25 μm) is set to 15 picoliters, and water droplets are dropped just above the fiber. The state of dripping is recorded on a high-speed recording device connected to a camera placed horizontally. From the viewpoint of image analysis later, the recorder is preferably a personal computer with a built-in high-speed capture device. In this measurement, images are recorded every 17 msec. In the recorded image, the first image of water droplets landing on the fiber is captured by the attached software FAMAS (software version is 2.6.2, analysis method is droplet method, analysis method is θ / 2 method, image processing algorithm is non-reflective, the image processing image mode is frame, the threshold level is 200, and no curvature correction is performed. angle. The fibers taken out from each of the projections (five points) to be measured are cut to a fiber length of 1 mm, and the fibers are placed on the sample table of the contact angle meter and maintained horizontally. Two different contact angles are measured for each fiber. N=5 contact angles are measured to one decimal place, and the contact angles at a total of 10 points are measured. The average value of these contact angle measurements (rounded to the second decimal place) is defined as the contact angle of the fiber with water. The measurement environment is a room temperature of 22±2° C. and a humidity of 65±2% RH. A smaller contact angle value means a higher hydrophilicity.

The nonwoven fabric 10 of this embodiment contains a fiber treatment agent. The fiber treatment agent adheres to the surface of the constituent fibers of the nonwoven fabric 10 and increases the hydrophilicity of the surface of the fiber compared to before the fiber treatment agent is adhered.
The fiber treatment agent contains polyorganosiloxane as component (A) and an anionic surfactant represented by formula (1) as component (B) below.

[(A) component]
The polyorganosiloxane may be linear or has a crosslinked two-dimensional or three-dimensional network structure, but is preferably substantially linear.

Specific examples of suitable polyorganosiloxanes for component (A) are alkylalkoxysilanes, arylalkoxysilanes, polymers of alkylhalosiloxanes, and cyclic siloxanes, and alkoxy groups are typically methoxy groups. is. As the alkyl group, an alkyl group that may have a side chain preferably has 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms, and still more preferably 1 to 4 carbon atoms. Examples of the aryl group include a phenyl group, an alkylphenyl group, an alkoxyphenyl group, and the like. A cyclic hydrocarbon group such as a cyclohexyl group or a cyclopentyl group, or an aralkyl group such as a benzyl group may be used instead of the alkyl group or the aryl group.
The component (A) can be used singly or in combination of two or more.
In addition, polyorganosiloxane is a polyorganosiloxane modified with a highly hydrophilic polyoxyethylene chain (POE chain) from the viewpoint of further promoting the penetration of surfactants and increasing the contact angle of the fiber surface by heating. It is a concept that does not include siloxane.

Polydimethylsiloxane, polydiethylsiloxane, polydipropylsiloxane, etc. are used as the most typical polyorganosiloxane preferred for the present invention, with polydimethylsiloxane being more preferred.

Further, the molecular weight of the polyorganosiloxane is preferably a high molecular weight. It is preferably 1,000,000 or less, more preferably 800,000 or less, and still more preferably 600,000 or less. As the polyorganosiloxane, two or more types of polyorganosiloxane having different molecular weights may be used. When two or more polyorganosiloxanes having different molecular weights are used, one of them preferably has a weight average molecular weight of 100,000 or more, more preferably 150,000 or more, and still more preferably 200,000 or more. is 1,000,000 or less, more preferably 800,000 or less, still more preferably 600,000 or less, and the other type preferably has a mass average molecular weight of less than 100,000, more preferably 50,000 or less, further preferably 30,000 It is 5,000 or less, more preferably 20,000 or less, preferably 2,000 or more, more preferably 3,000 or more, and still more preferably 5,000 or more. Further, a preferred blending ratio (former: latter) of polyorganosiloxane having a mass average molecular weight of 100,000 or more and polyorganosiloxane having a mass average molecular weight of less than 100,000 is preferably 1:10 to 4:1 by mass. , more preferably 1:5 to 2:1.

The weight average molecular weight of polyorganosiloxane is measured using GPC. Measurement conditions are as follows. Also, the calculation of the reduced molecular weight is performed with polystyrene.
Separation column: GMHHR-H + GMHHR-H (cation) (manufactured by Tosoh Corporation)
Eluent: 1 mmol/L Farmin DM20 (manufactured by Kao Corporation)/CHCl ₃
Solvent flow rate: 1.0 ml/min
Separation column temperature: 40°C

A commercially available product can also be used as the polyorganosiloxane as the component (A). For example, "KF-96H-1,000,000 Cs" manufactured by Shin-Etsu Chemical Co., Ltd., "SH200 Fluid 1000000Cs" manufactured by DuPont Toray Specialty Materials Co., Ltd., and those containing two types of polyorganosiloxane include: "KM-903" manufactured by Shin-Etsu Chemical Co., Ltd. and "BY22-060" manufactured by DuPont Toray Specialty Materials Co., Ltd. can be used.

（式中、Ｚはエステル基、アミド基、アミン基、ポリオキシアルキレン基、エーテル基又は２重結合を含んでいてもよい、炭素数１～１２の直鎖又は分岐鎖の炭化水素基を表わし、Ｒ₁及びＲ₂はそれぞれ独立に、エステル基、アミド基、ポリオキシアルキレン基、エーテル基又は２重結合を含んでいてもよい、炭素数２～１６の直鎖又は分岐鎖のアルキル基を表わし、Ｘは―ＳＯ₃Ｍ、―ＯＳＯ₃Ｍ又は―ＣＯＯＭを表わし、ＭはＨ、Ｎａ、Ｋ、Ｍｇ、Ｃａ又はアンモニウムを表わす。）
前記（Ｂ）成分は、一種を単独で又は２種以上を混合して用いることができる。 [(B) component]
The component (B) is an anionic surfactant represented by the following general formula (1).

(Wherein, Z represents an ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group, or a straight or branched hydrocarbon group having 1 to 12 carbon atoms, which may contain a double bond. , R ₁ and R ₂ each independently represent an ester group, an amide group, a polyoxyalkylene group, an ether group or a straight or branched alkyl group having 2 to 16 carbon atoms which may contain a double bond. X represents -SO ₃ M, -OSO ₃ M or -COOM, and M represents H, Na, K, Mg, Ca or ammonium.)
The component (B) may be used singly or in combination of two or more.

As will be described later, the following anionic surfactants represented by the general formula (1) are preferable from the viewpoint of uniformly attaching the component (A) to the fibers.
Z preferably represents a linear hydrocarbon group having 1 to 12 carbon atoms, which may contain an amide group, an amine group, a polyoxyalkylene group, or an ether group, more preferably having 2 to 8 carbon atoms. It represents a straight-chain hydrocarbon group, more preferably a straight-chain hydrocarbon group having 2 to 4 carbon atoms.
R ₁ and R ₂ each independently represent preferably an ester group, an amide group and/or a straight or branched C 2-16 alkyl group containing a double bond, more preferably an ester group or an amide and/or a straight or branched C4-14 alkyl group containing a double bond, more preferably a straight or branched C6-12 alkyl group containing an ester group .
X preferably represents _-SO3M , _-OSO3M or -COOM, more preferably _-SO3M .
M preferably represents H, Na or K.

Examples of the anionic surfactant in which X in formula (1) is —SO ₃ M, that is, the hydrophilic group is sulfonic acid or a salt thereof include dialkylsulfonic acid or a salt thereof. Specific examples of dialkylsulfonic acids include dicarboxylic acids such as dioctadecylsulfosuccinic acid, didecylsulfosuccinic acid, ditridecylsulfosuccinic acid, di-2-ethylhexylsulfosuccinic acid (dioctylsulfosuccinic acid), dialkylsulfosuccinic acids, dialkylsulfoglutaric acids, etc. is esterified and the alpha position of the diester is sulfonated, a saturated compound such as 2-sulfotetradecanoic acid 1-ethyl ester (or amide) sodium salt, or 2-sulfohexadecanoic acid 1-ethyl ester (or amide) sodium salt Alpha sulfo fatty acid alkyl ester (or amide) obtained by sulfonating the α-position of fatty acid or unsaturated fatty acid ester (or amide), dialkyl obtained by sulfonating internal olefin of hydrocarbon chain or internal olefin of unsaturated fatty acid Alkene sulfonic acids and the like can be mentioned. The number of carbon atoms in each of the two-chain alkyl groups of the dialkylsulfonic acid is preferably 4 or more and 14 or less, more preferably 6 or more and 10 or less.

More specifically, the anionic surfactant whose hydrophilic group is sulfonic acid or a salt thereof includes the following anionic surfactants.

X in formula (1) is —OSO ₃ M, that is, the anionic surfactant whose hydrophilic group is sulfuric acid or a salt thereof includes dialkyl sulfate esters, and specific examples thereof include 2-ethylhexyl sulfate. Sodium salts, compounds obtained by sulfating branched alcohols such as 2-hexyldecyl sulfate sodium salt, and branched alcohols such as polyoxyethylene 2-hexyldecyl sulfate and polyoxyethylene 2-hexyldecyl sulfate. Compounds such as POE chains introduced between sulfate groups, hydroxy fatty acid esters (or compounds obtained by sulphating amides).

More specifically, the anionic surfactant whose hydrophilic group is sulfuric acid or a salt thereof includes the following anionic surfactants.

X in the formula (1) is -COOM, that is, the anionic surfactant whose hydrophilic group is a carboxylic acid or a salt thereof includes dialkylcarboxylic acids, and specific examples thereof include 11-ethoxyheptadecane. Compounds obtained by alkoxylating the hydroxy moiety of hydroxy fatty acids such as carboxylic acid sodium salts and 2-ethoxypentacarboxylic acid sodium salts and sodiumizing the fatty acid moieties, and hydroxy fatty acid chlorides obtained by alkoxylating the amino groups of amino acids such as sarcosine and glycine. A sodium salt compound obtained by reacting and neutralizing the carboxylic acid of the amino acid portion with an alkali such as sodium hydroxide, a compound obtained by reacting the amino group of alginic acid with a fatty acid chloride, and the like can be mentioned.

As the anionic surfactant whose hydrophilic group is carboxylic acid or a salt thereof, more specifically, the following anionic surfactants can be mentioned.

When the polyorganosiloxane of component (A) described above is mixed with the anionic surfactant of component (B) and applied to the fiber surface, the interior of the fiber constituting the anionic surfactant of component (B) is removed by subsequent heat treatment. The penetration into the fiber is accelerated, and the polyorganosiloxane of the component (A) remains on the fiber surface, so that the hydrophilicity of the fiber surface is easily lowered by the heat treatment. This is because the polysiloxane chain of the polyorganosiloxane of component (A) and the alkyl chain of the anionic surfactant of component (B) are incompatible with each other, so that when the fibers are heated and melted, they are more compatible with each other. It is presumed that this occurs because the anionic surfactant permeates into the interior of the fiber. The component (B) anionic surfactant allows the component (A) polyorganosiloxane to adhere uniformly to the fibers.

The nonwoven fabric 10 of the present embodiment is obtained by partially subjecting a fiber web containing constituent fibers to which the above-described component (A) and component (B) are attached or a laminate of the fiber webs to a pressing process such as embossing. , is obtained by blowing hot air onto the fibrous web or a laminate of the fibrous webs for heat treatment. The projections 11ab, 11as, and 14 in such a nonwoven fabric 10 become bulkier and thicker as the area increases, so the large projections 11ab are larger than the middle projections 14, and the middle projections 14 are smaller projections. The surface of the projection is more easily exposed to hot air than 11as. In this manner, the degree of exposure to hot air can be varied according to the thickness of the projections, so the degree of heat treatment for each of the projections 11ab, 11as, 14 can be varied. As a result, in the nonwoven fabric 10 containing the components (A) and (B) described above, the hydrophilicity of the small protrusions 11as is higher than that of the medium protrusions 14, and the hydrophilicity of the medium protrusions 14 is higher than that of the large protrusions 11ab. higher than

As described above, the nonwoven fabric 10 of the present embodiment contains the component (A) and the component (B), and the large protrusions 11ab and the small protrusions 11as having different thicknesses, areas, and hydrophilicity are arranged in the longitudinal direction. A plurality of them are provided alternately in each of the X and lateral Y directions. Such a nonwoven fabric 10 has a pattern of large and small protrusions including protrusions 11ab and 11as with different degrees of hydrophilicity. It is easy to transfer to the convex portions 11as, and the remaining liquid on the nonwoven fabric 10 can be effectively suppressed. As a result, the nonwoven fabric 10 has good dryness while exhibiting hydrophilicity due to the components (A) and (B). In particular, as in the present embodiment, the hydrophilicity of the small protrusions 11as is higher than that of the medium protrusions 14, and the hydrophilicity of the medium protrusions 14 is higher than that of the large protrusions 11ab. Dryness can be made compatible more.
When the nonwoven fabric 10 of the present embodiment is used as the topsheet of an absorbent article, the topsheet does not lose its absorption performance even when the topsheet is exposed to a large amount of moisture such as urine, blood, and sweat. Since dryness can be maintained, good wearing feeling can be maintained.

Furthermore, in the nonwoven fabric 10 of the present embodiment, the large protrusions 11ab and the small protrusions 11as adjacent to each other in the longitudinal direction X and the lateral direction Y are connected without being separated by the compressed portions (fixed portions). Such connection facilitates the transfer of liquid such as urine and blood from the weakly hydrophilic large protrusions 11ab to the highly hydrophilic small protrusions 11as, and further transfers the liquid to the absorbent body side through the connection sites. Therefore, it is possible to more effectively suppress liquid residue on the nonwoven fabric 10 .

From the viewpoint of further improving the durable hydrophilicity of the nonwoven fabric 10, the nonwoven fabric 10 preferably contains the following component (C) as a fiber treatment agent.
(C) Any amphoteric surfactant of sulfobetaine type, carbobetaine type and imidazoline type, which may have an amide bond in the hydrocarbon chain of the hydrophobic group.
The component (C) may be used singly or in combination of two or more.

Examples of sulfobetaine-type surfactants include N-alkyl-N,N-dimethyl-N-sulfopropylammoniumsulfobetaine having an alkyl group having 10 to 18 carbon atoms, N-alkyl-N,N-dimethyl-N- (2-Hydroxysulfopropyl)ammonium sulfobetaine, N-alkanoylaminopropyl-N,N-dimethyl-N-sulfopropylammonium sulfobetaine having 10 to 18 carbon atoms in the alkanoyl group, N-alkanoylaminopropyl-N,N -dimethyl-N-(2-hydroxysulfopropyl)ammonium sulfobetaine. Among these, N-alkyl-N,N-dimethyl-N-(2-hydroxysulfopropyl)ammonium sulfobetaine is preferred.

Examples of carbobetaine surfactants include those having an alkyl group, alkenyl group or acyl group having 10 to 18 carbon atoms, such as betaine lauryldimethylaminoacetate, betaine myristyldimethylaminoacetate, betaine palmityldimethylaminoacetate. , stearyldimethylaminoacetate betaine, and the like. Among these, betaine stearyldimethylaminoacetate is preferred.

Examples of imidazoline surfactants include 2-alkyl-N-carboxymethylimidazolinium betaine, 2-alkyl-N-carboxyethylimidazolinium betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazoline. nium betaine and the like. Among these, 2-alkyl-N-carboxymethylimidazolinium betaines are preferred.

From the viewpoint of further improving the durable hydrophilicity of the nonwoven fabric 10, the component (C) is preferably a carbobetaine-type amphoteric surfactant, and more preferably betaine stearyldimethylaminoacetate.

From the viewpoint of achieving both hydrophilicity and dryness, the content ratio (A:B) of component (A) and component (B) in nonwoven fabric 10 is preferably 1:0.25 to 1:8. , more preferably 1:1 to 1:4.
From the viewpoint of further stabilizing the hydrophilic film formed by the components (B) and (C) and further improving the durable hydrophilicity, the content ratio of the component (B) and the component (C) in the nonwoven fabric 10 is The ratio (B:C) is preferably 1:0.75-1:3, more preferably 1:0.9-1:2.5.
From the viewpoint of achieving both hydrophilicity, dryness, and durable hydrophilicity, the content ratio of the component (A) in the nonwoven fabric 10 and the total amount of the components (B) and (C) is the mass ratio (A: B + C ), preferably 1:2 to 1:10, more preferably 1:3 to 1:8.
As used herein, the term "content rate" refers to the ratio (mass ratio) between the content rates of each component. “Content rate” is the ratio of the mass of each component to the total mass of the nonwoven fabric 10 . The content can be adjusted by the content (mass) of each component in the fiber treatment agent.

When analyzing the fiber treatment agent in the nonwoven fabric 10 containing the fiber treatment agent, it is preferable to analyze according to the following procedure. First, the nonwoven fabric to be analyzed is washed with an appropriate solvent. As a solvent for this washing, chloroform, hexane, methanol, ethanol, water, and a mixed solvent thereof can be used. When the nonwoven fabric to be analyzed is a constituent member of an absorbent article such as sanitary products or disposable diapers for children or adults, it is used to join the constituent member to be measured and other members in the absorbent article. After solidifying the adhesive by spraying a cold spray, the constituent member (nonwoven fabric) is peeled off and washed with a washing solvent.
Next, the solvent (washing solvent containing the fiber treatment agent) used to wash the nonwoven fabric to be analyzed is dried, and the residue is quantified to determine the total amount of the fiber treatment agent adhering to the nonwoven fabric. can be measured. In addition, after selecting an appropriate column and solvent for this residue according to its composition, each component is fractionated by high performance liquid chromatography, and each fraction is subjected to IR measurement, MS measurement, NMR measurement, The structure of each fraction can be identified by elemental analysis or the like. Moreover, when the fiber treatment agent contains a polymer compound, it becomes easier to identify the constituent components by using a method such as gel permeation chromatography (GPC) in combination.
If the residue is too small to establish details, the structure is identified by comparison of data from commercial or synthetic standards with data obtained from a small amount of residue.
In addition, if the residue consists of multiple compositions and cannot be sufficiently separated and identified only by column or solvent selection, pre-purification by liquid separation may be used. Specifically, water, an aqueous solution of a mixture of ethanol and water, an aqueous solution containing various salts, or the like is used as the aqueous phase, and petroleum ether, butanol, or the like is used as the oil phase. After standing, the phases are separated into an aqueous phase and an oil phase, and after separation and purification, each phase can be analyzed using gas chromatography, HPLC-MS, IR measurement, NMR measurement, elemental analysis, or the like. As an example, gas chromatography and HPLC-MS analysis methods are shown below.

・Gas chromatography conditions Apparatus: Agilent 6850GC (manufactured by Agilent Technologies Inc.)
Column: Ultra Alloy UA ⁺ -1 (HT) capillary column 15 m × 250 μm × 0.15 μm (manufactured by Frontier Labs)
Detector: Flame ion detector (FID)
Injection temperature: 300°C
Detector temperature: 350°C
He flow rate: 3.8 mL/min
・ HPLC-MS conditions HPLC-MS equipment: Agilent 1100 LC/MSD Model G1946D Mass Spectrometer (manufactured by Agilent Technologies)
Column: L-column ODS (manufactured by Chemicals Evaluation and Research Organization, particle size 5 μm, 4.6 × 150 mm)
Sample preparation: 1000-fold dilution with methanol Eluent A: 10 mM ammonium acetate aqueous solution Eluent B: 10 mM ammonium acetate methanol solution Gradient conditions: At the start (eluent A/eluent B = 30/70 (volume ratio)) → 10 minutes (30/70) → 55 minutes (0/100) → 65 minutes (0/100) → 66 minutes (30/70) → 75 minutes (30/70)
MS detection: Anion detection m/z60-1600, UV240nm

The content of component (A) in the fiber treatment agent is preferably 3% by mass or more, more preferably 5% by mass or more, and is preferably 30% by mass or less, more preferably 15% by mass or less, and It is preferably 3% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 15% by mass or less.
The content of component (B) in the fiber treatment agent is preferably 5% by mass or more, more preferably 7% by mass or more, and is preferably 40% by mass or less, more preferably 25% by mass or less, and It is preferably 5% by mass or more and 40% by mass or less, more preferably 7% by mass or more and 25% by mass or less.
The content of component (C) in the fiber treatment agent is preferably 5% by mass or more, more preferably 10% by mass or more, and is preferably 40% by mass or less, more preferably 25% by mass or less, and It is preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 25% by mass or less.

The fiber treatment agent applied to the nonwoven fabric 10 may contain components other than the components (A), (B) and (C) described above. Examples of other components include various nonionic surfactants such as phosphate ester type anionic surfactants, water-soluble silicones, POE alkyl ethers, POE alkyl esters and polyglyceryl fatty acid esters.

Each of the fiber treatment agents, specifically component (A), component (B) and component (C), can be present in a state of adhering to the surfaces of the constituent fibers forming the nonwoven fabric 10 . Such a fiber treatment agent is preferably present on one side of the nonwoven fabric 10, preferably on the side from which the projections 11a, 11as, 14 protrude.

From the viewpoint of achieving both durable hydrophilicity and dryness, the contact angles with water of the large protrusions 11ab, the small protrusions 11as, and the medium protrusions 14 of the nonwoven fabric 10 are preferably within the following ranges. However, the contact angle of the small protrusions 11as with water is set to be smaller than that of the large protrusions 11ab (small protrusions 11as<large protrusions 11ab). In addition, the contact angle of the middle convex portion 14 with water is set to be smaller than the large convex portion 11ab and larger than the small convex portion 11as (small convex portion 11as<medium convex portion 14<large convex portion 11ab). .

The difference in contact angle with water between the small projections 11as and the large projections 11ab is preferably 1° or more, more preferably 3° or more, and is preferably 20° or less, more preferably 10° or less. It is preferably 1° or more and 20° or less, more preferably 3° or more and 10° or less.
The contact angle of the small projections 11as with water is preferably 50° or more, more preferably 55° or more, still more preferably 60° or more, and preferably 85° or less, more preferably 80° or less, and even more preferably. is 70° or less, preferably 50° or more and 85° or less, more preferably 55° or more and 80° or less, and still more preferably 60° or more and 70° or less.
The contact angle of the large protrusions 11ab with water is preferably 55° or more, more preferably 65° or more, and preferably 90° or less, more preferably 80° or less, and preferably 55° or more and 90°. ° or less, more preferably 65° or more and 80° or less.

The difference in contact angle with water between the small protrusions 11as and the medium protrusions 14 is preferably 1° or more, more preferably 3° or more, and is preferably 15° or less, more preferably 8° or less. It is preferably 1° or more and 15° or less, more preferably 3° or more and 8° or less.
The contact angle of the central convex portion 14 with water is preferably 50° or more, more preferably 63° or more, and is preferably 85° or less, more preferably 75° or less, and more preferably 50° or more and 85°. ° or less, more preferably 63° or more and 75° or less.

From the viewpoint of further improving the dryness of the nonwoven fabric 10 by increasing the hydrophilicity gradient in each of the protrusions 11ab, 11as, 14, the area of each of the large protrusions 11ab, the small protrusions 11as, or the medium protrusions 14 in the nonwoven fabric 10 is preferably within the following range. However, from the same viewpoint as above, the area of the large protrusion 11ab is preferably larger than that of the small protrusion 11as (large protrusion 11ab>small protrusion 11as). Further, the area of the middle convex portion 14 is preferably smaller than the large convex portion 11ab and larger than the small convex portion 11as (large convex portion 11ab>medium convex portion 14>small convex portion 11as). The area of each protrusion is the average area of five arbitrarily selected protrusions.
The area of the large projections 11ab is preferably 101% or more, more preferably 125% or more, still more preferably 150% or more, and more preferably 300% or less, more preferably 300% or more, with respect to the area of the small projections 11as. It is 250% or less, more preferably 200% or less, preferably 101% or more and 300% or less, more preferably 125% or more and 250% or less, still more preferably 150% or more and 200% or less.
The area of the small projections 11as is preferably 30 mm ² or more, more preferably 45 mm ² or more, more preferably 80 mm ² or less, more preferably 65 mm ² or less, and more preferably 30 mm ² or more and 80 mm ² or less. It is preferably 45 mm ² or more and 65 mm ² or less.
The area of the large convex portion 11ab is preferably 70 mm ² or more, more preferably 80 mm ² or more, more preferably 200 mm ² or less, more preferably 100 mm ² or less, and more preferably 70 mm ² or more and 200 mm ² or less. It is preferably 80 mm ² or more and 100 mm ² or less.

The area of the large protrusions 11ab is preferably 101% or more, more preferably 120% or more, and preferably 200% or less, more preferably 140% or less, with respect to the area of the middle protrusions 14, and It is preferably 101% or more and 200% or less, more preferably 120% or more and 140% or less.
The area of the central convex portion 14 is preferably 40 mm ² or more, more preferably 60 mm ² or more, more preferably 110 mm ² or less, more preferably 80 mm ² or less, and more preferably 40 mm ² or more and 110 mm ² or less. It is preferably 60 mm ² or more and 80 mm ² or less.

As in the present embodiment, when the protrusions 11ab, 11as and 14 are connected to each other due to the discontinuity of the fixed portion rows 15A and 15B, it is assumed that the fixed portion rows 15A and 15B are continuous. , and the areas of the convex portions 11ab, 11as, and 14 defined by the continuous fixed portion rows 15A and 15B are defined as the areas of the convex portions 11ab, 11as, and 14, respectively.

From the viewpoint of easily imparting hydrophilicity to the nonwoven fabric 10, the thickness of each of the large protrusions 11ab, the small protrusions 11as, and the medium protrusions 14 in the nonwoven fabric 10 is preferably within the following ranges. However, from the same viewpoint as above, the thickness of the large protrusion 11ab is preferably larger than that of the small protrusion 11as (large protrusion 11ab>small protrusion 11as). Further, the thickness of the middle convex portion 14 is preferably smaller than the large convex portion 11ab and larger than the small convex portion 11as (large convex portion 11ab>medium convex portion 14>small convex portion 11as).
The thickness of the large protrusions 11ab is preferably 101% or more, more preferably 110% or more, and preferably 125% or less, more preferably 120% or less, with respect to the thickness of the small protrusions 11as. It is preferably 101% or more and 125% or less, more preferably 110% or more and 120% or less.
The thickness of the small projections 11as is preferably 0.60 mm or more, more preferably 0.75 mm or more, and is preferably 2.00 mm or less, more preferably 1.90 mm or less, and more preferably 0.60 mm or more. 2.00 mm or less, more preferably 0.75 mm or more and 1.90 mm or less.
The thickness of the large convex portion 11ab is preferably 0.60 mm or more, more preferably 0.85 mm or more, and is preferably 2.20 mm or less, more preferably 2.10 mm or less, and more preferably 0.60 mm or more. 2.20 mm or less, more preferably 0.85 mm or more and 2.10 mm or less.

The thickness of the large protrusions 11ab is preferably 101% or more, more preferably 102% or more, and preferably 115% or less, more preferably 108% or less, with respect to the thickness of the middle protrusions 14. It is preferably 101% or more and 115% or less, more preferably 102% or more and 108% or less.
The thickness of the central protrusion 14 is preferably 0.60 mm or more, more preferably 0.80 mm or more, and is preferably 2.30 mm or less, more preferably 2.00 mm or less, and more preferably 0.60 mm or more. 2.30 mm or less, more preferably 0.80 mm or more and 2.00 mm or less.

Each of the thicknesses of the first row of protrusions 11, the second row of protrusions 12, and the third row of protrusions 13 is defined by the maximum length virtual line segment along the lateral direction Y of each row of protrusions and the ridge line of the row of protrusions. It is the sheet thickness at the intersection of , and is the arithmetic mean value of the thicknesses (mm) at five locations on the sheet when a load of 50 Pa is applied. The thickness is measured by magnifying and observing the cross section of the sheet using a microscope (eg, VHX-6000 manufactured by Keyence Corporation).

As shown in FIG. 2, in the first row of protrusions 11 of the present embodiment, first high-density regions S1 are intermittently formed along the direction in which the first row of protrusions 11 extends (longitudinal direction X). there is In the first row of protrusions 11 of the present embodiment, large protrusions 11ab and small protrusions 11as are connected in the vertical direction X via a first high-density region S1. The first high-density region S1 is a portion where the existence density of the constituent fibers of the nonwoven fabric 10 (hereinafter, "the existence density of the constituent fibers" is also simply referred to as the "fiber density") is higher than the convex portions 11ab, 11as, and 14. and has a lower fiber density than the fixed portion 15 . The first high-density region S1 is a region whose maximum thickness is smaller than the maximum thicknesses of the first row of protrusions 11 and the rows of protrusions 12 and 13 . With such a configuration, regions having different fiber densities are formed in the first convex row 11, so that the excreted liquid can be easily transferred to the absorbent body through the first high-density region S1 having a high fiber density. . As a result, it is possible to further reduce liquid residue on the topsheet and return of excreted liquid from the absorbent body to the topsheet side.

The first high-density region S1 is preferably a region that has not been pressed. That is, it is preferable that the first high-density region S1 is not the compressed portion. With such a configuration, the nonwoven fabric 10 becomes soft in the first high-density region S1, maintains a high fit of the first projection rows 11, 11 to the skin, and facilitates diffusion of the excreted liquid in the longitudinal direction X. It tends to occur along the 1-projection row 11 . As a result, liquid residue on the top sheet and return of excreted liquid from the absorbent body to the top sheet side are further reduced, resulting in a better touch.

In the first high-density region S1 of the present embodiment, in plan view, fixed portions 15g, 15h, 15m, and 15n exist at positions corresponding to intersections between the first fixed portion row 15A and the second fixed portion row 15B. When viewed along the extending direction of the first row of protrusions 11, one of the four vertices forming the rhomboid section of the large protrusion 11ab and the small protrusion 11as Each is formed at a position that shares one of the four vertices forming the rhombic section (see FIG. 2). That is, when the first convex portion row 11 includes the first high-density region S1, the first convex portion row 11 includes the large convex portion 11ab and the small convex portion via the first high-density region S1. 11as are alternately arranged in rows. As a result, the excretory fluid that has moved to the side of the small projections 11as that are smaller in planar view area than the large projections 11ab is less likely to come into contact with the wearer's skin. The discomfort caused by contact with the nonwoven fabric 10 can be further reduced.

In the first high-density region S1 in the present embodiment, when the nonwoven fabric 10 contains thermally extensible fibers to be described later, the intervals between the fixed portions 15g, 15h, 15m, and 15n are appropriately adjusted with respect to the nonwoven fabric 10. After that, the nonwoven fabric 10 is subjected to an air-through process, which will be described later, or a process of blowing hot air to recover the bulkiness of the sheet. By performing these processes, the thickness of the sheet located at the formation scheduled portion of the first high-density region S1 is recovered, and the maximum thickness is greater than the maximum thickness of the first row of protrusions 11 and the rows of protrusions 12 and 13. The area is small and larger than the maximum thickness of the fixing portion 15 .

In each of the second row of protrusions 12 and the third row of protrusions 13 of the present embodiment, the second high-density regions S2 are preferably intermittently formed along the direction in which the rows of protrusions 12 and 13 extend. (See Figure 2). In each of the second convex portion row 12 and the third convex portion row 13 of the present embodiment, the central convex portions 14 are connected to each other in the longitudinal direction X via the second high-density region S2. In the present embodiment, the rows of protrusions 12 and 13 extend in the vertical direction X while meandering, so the second high-density regions S2 are also intermittently formed in the vertical direction X. As shown in FIG. The second high-density region S<b>2 is a region where the fiber density of the nonwoven fabric 10 is higher than that of the first convex row 11 and convex rows 12 and 13 and lower than that of the fixed portion 15 . The second high-density region S2 is a region having a maximum thickness smaller than the maximum thickness of the first row of protrusions 11 and the rows of protrusions 12 and 13 and larger than the maximum thickness of the fixing portion 15. . With such a configuration, portions having different densities of the constituent fibers are formed in each of the projection rows 12 and 13, so that the excreted liquid is directed to the absorbent body side through the second high-density region S2 having a high density of the constituent fibers. As a result, it is possible to reduce liquid residue on the topsheet and return of excreted liquid from the absorbent body to the topsheet side.

Moreover, it is preferable that the second high-density region S2 is a region that is not subjected to compression processing. That is, it is preferable that the second high-density region S2 is not the compressed portion. As a result, the nonwoven fabric 10 becomes soft in the second high-density region S2, and when the wearer moves such as walking, the first convex row 11 maintains a high degree of fit to the skin, and the vertical direction of the excreted liquid is maintained. Diffusion to X tends to occur along the extending direction of the first row of protrusions 11 . As a result, the liquid residue on the nonwoven fabric 10 and the liquid return of the excreted liquid from the absorbent body to the top sheet side are further reduced, and the touch is further improved.

In the second high-density region S2 of the present embodiment, when the second protrusions 12a adjacent to each other along the longitudinal direction X are viewed from above, one of the four vertices forming the parallelogram-shaped section is positioned at the adjacent second vertices. A plurality of protrusions 12a are intermittently arranged at positions shared by the two protrusions 12a. Further, as shown in FIG. 2, the second high-density region S2 is a portion where the fiber density of the constituent fibers of the nonwoven fabric 10 is higher than that of the first convex row 11 and the convex rows 12 and 13, and the fixed portion This is a portion with a lower fiber density than 15. The first high-density region S1 is a region whose maximum thickness is smaller than the maximum thicknesses of the first row of protrusions 11 and the rows of protrusions 12 and 13 . The second high-density region S2 in this embodiment can be formed by the same method as the first high-density region S1.

Also, the first row of protrusions 11 is preferably connected to the second row of protrusions 12 and the third row of protrusions 13 in the horizontal direction Y via the second high-density region S2. In this case, the fixed portions 15g, 15h, 15m, and 15n may be formed as discontinuous lines, and the second high-density region S2 may be formed in areas where the fixed portions 15 do not exist.

The second high-density region S2 of the present embodiment is formed at a position where the fixed portions 15g, 15h, 15m, and 15n do not exist at the positions where the first fixed portion row 15A and the second fixed portion row 15B intersect. , a position where one of the four vertices forming the parallelogram-shaped section of the second convex portion 12a and one of the four vertices forming the rhomboid-shaped section of the large convex portion 11ab are shared, and the third convex They are formed at positions that share one of the four vertices forming the parallelogram of the portion 13a and one of the four vertices forming the rhomboidal section of the large convex portion 11ab. In addition, the second high-density region S2 includes one of the four vertices forming the parallelogram section of the second protrusion 12a and one of the four vertices forming the rhomboid section of the small protrusion 11as. and share one of the four vertices forming the parallelogram-shaped section of the third convex portion 13a and one of the four vertices forming the rhombus-shaped section of the small convex portion 11as. are formed at positions where With such a configuration, the liquid excreted in the first row of protrusions 11 can be transferred not only in the longitudinal direction X but also to the second row of protrusions 12 and the third row of protrusions 13 existing in the horizontal direction Y. As a result, the excreted liquid is less likely to remain in the nonwoven fabric 10, and the liquid is more likely to migrate to the absorbent body. As a result, the amount of liquid returned to the nonwoven fabric 10 is reduced, and the amount of liquid remaining on the surface is also reduced, resulting in good texture.

In the nonwoven fabric 10 of the present embodiment, as shown in FIG. 3(b), a plurality of recesses 17 having a thickness smaller than that of the other portions are formed in the portions where the fixed portions 15g, 15h, 15m, and 15n are present. there is In the cross-sectional view shown in FIG. 3B, a large convex portion 11ab is formed between the concave portions 17 formed by the first fixing portion 15g and the third fixing portion 15m. Further, a second convex portion 12a is provided between the concave portions 17 formed by the second fixing portion 15h and the third fixing portion 15m. A third convex portion 13a is provided between the concave portions 17 formed by the first fixing portion 15g and the fourth fixing portion 15n. Similarly, a small projection 11as is provided between the recesses 17 formed by the second fixing portion 15h and the fourth fixing portion 15n.

The length W1 (see FIG. 1) in the horizontal direction Y of the first high density region S1 is preferably 0.5 mm or more, more preferably 0.8 mm or more, and is preferably 5 mm or less, more preferably 3 mm or less. be. The length of the first high-density region S1 in the vertical direction X can be in the same range as the length W1 described above. In the embodiment shown in FIG. 1, the length W1 in the horizontal direction Y and the length in the vertical direction X of the first high-density region S1 are the same as the first fixed portion 15g and the second fixed portion adjacent to each other in the first fixed portion row 15A. It can be appropriately adjusted by changing the interval between the portion 15h and the interval between the third fixing portion 15m and the fourth fixing portion 15n adjacent to each other in the second fixing portion row 15B.

Similarly, the length W2 (see FIG. 1) in the horizontal direction Y of the second high-density region S2 is not particularly limited as long as it is smaller than the lengths in the horizontal direction Y of the second row 12 and the third row 13 of projections. However, it is preferably 0.5 mm or more, more preferably 0.8 mm or more, and preferably 5 mm or less, more preferably 3 mm or less. The length of the second high-density region S2 in the vertical direction X can be in the same range as the length W2 described above. In the embodiment shown in FIG. 1, the length W2 in the horizontal direction Y and the length in the vertical direction X of the second high-density region S2 can be appropriately adjusted by changing the dimensions of the pressing process (squeezing process). can. In addition, the length W2 in the horizontal direction Y and the length in the vertical direction X of the second high-density region S2 are the distance between the first fixed portion 15g and the second fixed portion 15h adjacent to each other in the first fixed portion row 15A, and It can be appropriately adjusted by changing the distance between the third fixing portion 15m and the fourth fixing portion 15n adjacent to each other in the second fixing portion row 15B.

The maximum length W5 (see FIG. 1) along the lateral direction Y of the second row of protrusions 12 and the third row of protrusions 13 is each independently preferably 3 mm or more, more preferably 5 mm or more, and preferably 15 mm or less. , more preferably 10 mm or less. The length W5 in this embodiment can be appropriately adjusted, for example, by changing the respective lengths of the second fixing portion 15h and the fourth fixing portion 15n.

The density (g/cm ³ ) of each of the rows of protrusions 11, 12, 13 and each of the high-density regions in the nonwoven fabric 10 is measured at a predetermined position using a laser thickness gauge (eg, XS-1100 manufactured by Keyence Corporation). It can be obtained by dividing the basis weight B1 (g/m ² ) of the nonwoven fabric 10 by the arithmetic mean value (Tx) of the thicknesses (mm) at the three locations. In the formula, x indicates that the thickness and density are differentiated between each row of protrusions and each high-density region.
Density Dx (g/cm ³ )=(B1×0.0001)/(Tx×0.1)

As shown in FIGS. 3(a) and 3(b), the nonwoven fabric 10 of the present embodiment includes an upper layer 40 from which the projections 11ab, 11as, and 14 protrude, and a lower layer 50 laminated on the upper layer 40. It has a laminated structure.
The nonwoven fabric 10 of the present embodiment has an upper layer 40 and a lower layer 50 separated by a boundary surface F, a fixed portion 15 in which these layers 40 and 50 are joined together, and a fixed portion in which the upper layer 40 and the lower layer 50 are joined. 15 and a non-bonded portion that is not joined. A boundary surface F between the upper layer 40 and the lower layer 50 exists in the non-fixed portion, but the boundary surface F does not exist in the fixed portion 15 . The fixed portion 15 in the present embodiment is formed by laminating a fiber assembly constituting the upper layer 40 and a fiber assembly constituting the lower layer 50 to form a laminate, and embossing the laminate. , the adhesive may be applied intermittently between the layers 40,50.

As shown in FIG. 3B, when the fixed portion 15 is formed to compress and join the upper layer 40 and the lower layer 50, the surface of the upper layer 40 of the nonwoven fabric 10 has an uneven shape. Concave portions 17 are formed in each of the upper layer 40 and the lower layer 50 of the fixed portion 15 of the nonwoven fabric 10 . Protrusions 11ab, 11as, and 14 are provided between the recesses 17 on the surface of the upper layer 40 . The protrusions 11ab, 11as, and 14 are present in a region surrounded by the fixing portion 15 forming the recess 17 . The fixed portions 15 in this embodiment can be, for example, fixed portion rows 15A and 15B shown in FIG. 1, or fixed portions 15g, 15h, 15m, and 15n.

The nonwoven fabric 10 is preferably configured such that the contact angle between the fibers forming the upper layer 40 and water is larger than the contact angle between the fibers forming the lower layer 50 and water. That is, the hydrophilicity of the upper layer 40 is preferably lower than that of the lower layer 50 .

The contact angle between the fiber and water can be appropriately adjusted, for example, by changing the raw material of the fiber, or by subjecting the fiber surface to hydrophilic treatment or hydrophobic treatment. By making the hydrophilicity of the upper layer 40 lower than that of the lower layer 50, a hydrophilicity gradient is formed between the upper layer 40 and the lower layer 50, so that the hydrophilicity of the lower layer 50 is higher than that of the upper layer 40. Body fluids can be made easier to permeate into the highly hydrophilic lower layer 50 side. As a result, liquid hardly remains in the nonwoven fabric 10, and the sheet has a better touch feeling.

From the viewpoint of achieving the above effects more reliably, the difference in contact angle with water between the constituent fibers of the upper layer 40 and the lower layer 50 is preferably 1° or more, more preferably 5° or more. It is 20° or less, more preferably 15° or less, more preferably 1° or more and 20° or less, more preferably 5° or more and 15° or less. Such a contact angle is the contact angle with water of constituent fibers taken out from the surface of each layer, and can be measured by the above-described <Method for measuring contact angle with water>.

The upper layer 40 of the nonwoven fabric 10 of this embodiment is composed of a fiber assembly containing thermally extensible fibers 41 . The thermally extensible fibers 41 contained in the upper layer 40 of the nonwoven fabric 10 are elongated by heating at a heating temperature of preferably 90° C. or higher, more preferably 110° C. or higher, and preferably 130° C. or lower. Fiber. Examples of the thermally extensible fibers 41 include fibers that are elongated by changing the crystalline state of the resin by heating, or fibers that are crimped and whose apparent length is elongated after the crimp is released. . A suitable fiber diameter of the thermally extensible fibers 41 will be described later.

On the other hand, the lower layer 50 of the nonwoven fabric 10 is composed of a fiber assembly that does not contain the thermally extensible fibers 41 or contains the thermally extensible fibers 41 in a lower mass ratio than the upper layer 40 . With such a configuration, the above-described hydrophilicity gradient is created, so body fluid excreted to the upper layer 40 side can easily permeate to the highly hydrophilic lower layer 50 side. Such a nonwoven fabric can be produced, for example, by the air-through process described in JP-A-2010-115479.

A preferred thermally extensible fiber 41 is composed of a first resin component and a second resin component having a melting point or softening point lower than that of the first resin component, and the second resin component partially or entirely covers the surface of the fiber. Composite fibers that exist continuously can be mentioned. It is also preferable that the fibers are thermally fused with other fibers during thermal elongation. Examples of the first resin component include polypropylene (PP), polyethylene terephthalate, and polybutylene terephthalate. Examples of the second resin component include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene ( LLDPE), ethylene propylene copolymer, polystyrene, polypropylene (PP), copolyester and the like. Among these components, it is preferable to use polypropylene as the first resin component and high-density polyethylene as the second resin component in that a thermally extensible fiber imparted with thermal fusion bondability can be easily obtained. Such thermally extensible fibers can be produced, for example, by the method described in JP-A-2005-350836.

Whether or not the nonwoven fabric 10 contains the thermally extensible fibers 41 can be determined by measuring the thermal elongation rate of the fibers taken out from the nonwoven fabric 10 by the following method.
<Method for identifying thermally extensible fibers>
First, ten fibers are collected from the nonwoven fabric 10 . The length of the fiber to be collected shall be 1 mm. The collected fibers are sandwiched between slides, and the total length of the sandwiched fibers is measured. A digital microscope VHX-6000 manufactured by Keyence Corporation is used for the measurement. Measurement was performed by observing the fiber at a magnification of 50 to 100 times and using a measurement tool incorporated in the apparatus for the observed image. Let the length obtained by the said measurement be "total length of the fiber extracted from the nonwoven fabric 10" F1. The fiber whose total length has been measured is placed in a sample container for DSC6200 manufactured by SII Nanotechnology Co., Ltd. (product name: robot container 52-023P, 15 μL, made of aluminum). The container containing the fiber is placed in a sample storage area in a heating furnace of DSC6200, which is previously set at a temperature 10° C. lower than the melting point or softening point of the low melting point component (second resin component) of the fiber. The temperature measured by the thermocouple installed directly under the sample storage area of the DSC6200 (display name in the measurement software: sample temperature) is ±1°C, which is 10°C higher than the melting point or softening point of the low-melting component (second resin component). After reaching the range of , heat for 60 seconds and then quickly remove. After the heat treatment, the fiber is taken out from the DSC sample container, sandwiched between slides, and the total length of the sandwiched fiber is measured. For the measurement, a microscope VHX-900 and a lens VH-Z20R manufactured by Keyence Corporation were used. Measurement was performed by observing the fiber at a magnification of 50 to 100 times and using a measurement tool incorporated in the apparatus for the observed image. The length obtained by the measurement is defined as "total length of fiber after heat treatment" F2. The thermal elongation rate (%) is calculated from the following formula. If the thermal elongation rate is greater than 0%, it is determined that the fiber to be measured is a thermally extensible fiber, and if the thermal elongation rate is 0%, it is determined that the fiber to be measured is not a thermally extensible fiber. .
Fiber thermal elongation rate (%) = 100 × (F2 - F1) / F1

From the viewpoint of efficiently forming the uneven shape, the thermally extensible fiber 41 preferably has an elongation rate of 5% or more, more preferably 10% or more at a temperature 10° C. higher than the melting point or softening point of the second resin component. Yes, preferably 40% or less, more preferably 30% or less. The elongation rate can be calculated by measuring the fiber length before and after heating.

The nonwoven fabric 10 of this embodiment contains thermally extensible fibers 41 and other fibers 42 other than the thermally extensible fibers in the upper layer 40 . The "fibers other than thermally extensible fibers" are fibers having an elongation rate of less than 5%.
The content of the thermally extensible fibers 41 in the upper layer 40 of the nonwoven fabric 10 is preferably 60% by mass or more, more preferably 70% by mass or more, and preferably 100% by mass or less, more preferably, in the total mass of the upper layer 40. It is 95% by mass or less. In addition, the upper layer 40 may not contain fibers other than the thermally extensible fibers, or the content of the thermally extensible fibers in the upper layer 40 is preferably 5% by mass or more in the total mass of the upper layer 40, It is more preferably 10% by mass or more, preferably 40% by mass or less, and more preferably 30% by mass or less.

From the viewpoint of providing dryness and good texture as a surface material, the average fiber diameter of the thermally extensible fibers 41 constituting the upper layer 40 is preferably 1.5 when expressed in fiber fineness (decitex: dtex). 2 dtex or more, more preferably 2.2 dtex or more, still more preferably 3.0 dtex or more, preferably 5.5 dtex or less, more preferably 4.4 dtex or less, still more preferably 3.5 dtex or less, and preferably 1 .2 dtex or more and 5.5 dtex or less, more preferably 2.2 dtex or more and 4.4 dtex or less, and still more preferably 3.0 dtex or more and 3.5 dtex or less.
From the viewpoint of providing dryness and good texture as a surface material, the average fiber diameter of the fibers constituting the upper layer 40 is preferably 1.0 dtex or more, or more when expressed in fiber fineness (decitex: dtex). Preferably 1.5 dtex or more, more preferably 2.0 dtex or more, preferably 7.0 dtex or less, more preferably 6.0 dtex or less, still more preferably 5.0 dtex or less, and preferably 1.0 dtex or more7 0 dtex or less, more preferably 1.5 dtex or more and 6.0 dtex or less, and still more preferably 2.0 dtex or more and 5.0 dtex or less.
From the viewpoint of providing dryness and good texture as a surface material, the average fiber diameter of the constituent fibers of the lower layer 50 is preferably 0.5 dtex or more, more preferably 0.5 dtex or more, when expressed in fiber fineness (decitex: dtex). is 1.0 dtex or more, more preferably 1.5 dtex or more, preferably 4.0 dtex or less, more preferably 3.5 dtex or less, still more preferably 3.0 dtex or less.
When the upper layer 40 or the lower layer 50 contains a plurality of types of fibers, the average fiber diameter of the fiber having the smallest average fiber diameter among the fibers constituting the upper layer 40 and the average fiber diameter of the fibers constituting the lower layer 50 It is sufficient that each of the fibers having a large .DELTA.

The fineness of fibers can be measured by the following method. That is, the nonwoven fabric 10 is cut into a rectangular shape of 50 mm×100 mm (area 5000 mm ² ) from the nonwoven fabric 10 in a state where no load is applied to prepare a measurement sample. Next, regarding the fineness of the fibers of the upper layer 40, a cross-sectional view of the measurement sample is taken, and 10 standard fibers at a position spaced 0.1 mm from the surface of the upper layer 40 of the measurement sample are subjected to fiber thickness. The thickness is actually measured using an electron microscope, and the arithmetic mean value Dn (μm) of the fiber thickness is calculated. Next, using a differential scanning calorimeter (DSC), the standard fiber constituent resin is specified at a position spaced 0.1 mm from the surface, and the theoretical fiber density Pn (g/cm ³ ) is obtained. . From the obtained arithmetic mean value Dn (μm) of the fiber thickness and the theoretical fiber density Pn (g/cm ³ ), the weight (g) per 10000 m of fiber length is calculated, and this calculated value is used as the upper layer 40 fiber fineness (dtex). Regarding the fineness of the fibers of the lower layer 50, a cross-sectional view of the measurement sample is taken, and 10 standard fibers at a position spaced 0.1 mm from the surface of the lower layer 50 are targeted, and the fineness of the fibers on the surface side Measure in the same manner as

The nonwoven fabric 10 preferably has a flat surface on the side opposite to the direction in which the projections 11ab, 11as, 14 protrude. The opposite surface in this embodiment is the surface of the lower layer 50 . When the nonwoven fabric 10 having such a structure is used for the topsheet of an absorbent article, by placing the flat surface of the nonwoven fabric 10 in contact with the constituent member of the absorbent article (for example, an absorbent body), The contact area with the nonwoven fabric 10 can be increased. As a result, the liquid that has permeated the nonwoven fabric 10 can be quickly transferred to constituent members such as the absorber, and as a result, the amount of liquid returning to the nonwoven fabric 10 can be reduced.

As the constituent fibers of the nonwoven fabric 10, the above-described thermally extensible fibers, in addition to or instead of this, polyester, polypropylene, etc., having a melting point higher than the temperature at which the thermal extension of the thermally extensible fibers occurs. A core-sheath structure type (including side-by-side type) that uses heat-fusible fibers containing one or more thermoplastic resins, natural fibers such as cotton and pulp, rayon and acetate fibers, polypropylene or polyester as the core component, and polyethylene as the sheath component. ) Fibers that do not have heat extensibility such as conjugate fibers.

In the upper layer 40 of the present embodiment, the components (A) and (B), which are fiber treatment agents, and the component (C) are adhered to the surfaces of the constituent fibers 41 and 42 . That is, the upper layer 40 contains component (A), component (B) and component (C).
As a method for attaching the fiber treatment agent to the surface of the constituent fibers 11, various known methods can be employed without particular limitation. Examples thereof include spray coating, slot coater coating, roll transfer coating, and immersion in a fiber treatment agent. These treatments may be carried out on the fibers before they are formed into webs, or after the fibers have been formed into webs by various methods.

When the nonwoven fabric 10 has an upper layer 40 and a lower layer 50, the lower layer 50 may or may not contain a fiber treatment agent.

In this embodiment, the nonwoven fabric 10 has a laminated structure in which the upper layer 40 and the lower layer 50 are laminated, but the nonwoven fabric 10 may have a single layer structure. When the nonwoven fabric 10 has a single-layer structure, it may be a mixture of thermally extensible fibers and other fibers, or may consist of a single type of fiber.
When the nonwoven fabric 10 has a single layer structure, the content of the thermally extensible fibers 41 in the nonwoven fabric 10 is preferably 25% by mass or more, more preferably 40% by mass or more, based on the total mass of the nonwoven fabric 10. is 100% by mass or less, more preferably 60% by mass or less.

The nonwoven fabric 10 of this embodiment is for absorbent articles, and is used as a constituent member of absorbent articles. In particular, the nonwoven fabric 10 of the present embodiment can be suitably used as a topsheet of absorbent articles.
An absorbent article generally has a vertically long shape having a longitudinal direction corresponding to a direction extending from the wearer's abdomen to the back through the crotch and a width direction orthogonal thereto. The absorbent article has a crotch part arranged in the crotch part of the wearer and an abdominal part and a back part extending in the front and rear of the crotch part. The crotch part has an excretory part-facing region including an excretory part-facing part that is arranged to face the wearer's excretory part such as the vaginal opening when the absorbent article is worn. They are located in the longitudinal center, the widthwise center, and the vicinity thereof.

Absorbent articles generally include a topsheet positioned on the wearer's skin-facing side, a backsheet positioned on the non-skin-facing side, and an absorbent body interposed between the topsheet and the backsheet. As the surface sheet, one or a plurality of liquid-permeable sheets such as nonwoven fabrics and perforated films can be used.

On the other hand, as the back sheet, for example, a liquid-impermeable or liquid-impermeable film, a spunbonded, meltblown, or spunbonded nonwoven fabric can be used. A plurality of micropores may be provided in a liquid-impermeable or liquid-impermeable film to impart water vapor permeability to the film. For the purpose of further improving the feel of the absorbent article, a sheet having good texture such as a non-woven fabric may be laminated on the outer surface of the backsheet.

The absorbent body has an absorbent core. The absorbent core is, for example, a pile of hydrophilic fibers such as pulp and cellulose, a mixed pile of hydrophilic fibers and absorbent polymer, a pile of absorbent polymer, and two absorbent sheets. It is composed of a laminated structure or the like in which an absorbent polymer is carried between them. At least the skin-facing surface of the absorbent core may be covered with a liquid-permeable core-wrap sheet, or the entire surface including the skin-facing surface and the non-skin-facing surface may be covered with the core-wrap sheet. . 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.

As used herein, the term “skin-facing surface” refers to the surface of the absorbent article or its constituent members (eg, absorbent body) that faces the wearer's skin when the absorbent article is worn, that is, the surface of the absorbent article that faces the wearer's skin. The "non-skin facing surface" is the side of the absorbent article or its constituent members opposite to the skin side when the absorbent article is worn, that is, the side relatively far from the wearer's skin. It is the surface. It should be noted that the term "when worn" as used herein means a state in which the absorbent article is maintained in a normal and appropriate wearing position, that is, in a correct wearing position of the absorbent article.

In addition to the above-described topsheet, backsheet, and absorbent body, leakage-preventing cuffs extending in the longitudinal direction are arranged on both sides along the longitudinal direction on the side facing the skin, depending on the specific use of the absorbent article. Sometimes. A leak-tight cuff generally has a proximal end and a free end. The leak-proof cuff has a base end on the skin-facing side of the absorbent article and stands up from the skin-facing side. The leak-tight cuff is constructed from a liquid-resistant or water-repellent and breathable material. An elastic member made of rubber thread or the like may be arranged in a stretched state at or near the free end of the leak-proof cuff. When the absorbent article is worn, the contraction of the elastic member causes the leak-proof cuff to stand up toward the wearer's body, and the liquid excreted on the top sheet flows along the top sheet and becomes absorbent. Leakage to the outside in the width direction of the article is effectively prevented. In addition, the absorbent article may further have an adhesive layer on the surface of the non-skin facing surface. The pressure-sensitive adhesive layer is used to fix the absorbent article to underwear or another absorbent article while the absorbent article is worn.

Absorbent articles broadly include those that are worn on the body and have the function of absorbing and retaining excrement excreted from the body. Examples of such absorbent articles include disposable diapers, sanitary napkins, incontinence pads, panty liners, and the like.

When the nonwoven fabric 10 of the above-described embodiment is used as the topsheet, the absorbent article preferably includes the nonwoven fabric 10 with the longitudinal direction X aligned with the longitudinal direction of the absorbent article. Moreover, it is preferable that the surface of the nonwoven fabric 10 on which the protrusions 11ab, 11as, and 14 protrude is the surface facing the skin.

Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments.
For example, in the above-described embodiment, each of the first row of projections 11, the second row of projections 12, and the third row of projections 13 is connected in the vertical direction X between adjacent projections in the vertical direction X. However, it is also possible to adopt a form in which the convex portions adjacent to each other in the longitudinal direction X are separated by the compressed portion.
In addition, although the heights of the central convex portions 14 forming the second convex portion row 12 and the third convex portion row 13 do not change substantially, a plurality of central convex portions 14 having different heights are fixed. A form formed along a direction may be used.

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.

[Example 1]
An absorbent article was manufactured that had the nonwoven fabric 10 having the pattern of large and small protrusions shown in FIG. 1 and the second and third protrusion rows 12 and 13 as the topsheet. The configuration of the absorbent article other than the nonwoven fabric 10 was the same as that of a sanitary napkin (Laurier Hikikirei Guard (registered trademark) with feathers for day use) manufactured by Kao Corporation. The nonwoven fabric 10 was a sheet of single-layer structure composed of the first fibers and the second fibers shown in Table 1 below, and had the pattern of large and small protrusions shown in FIG. In such a pattern of large and small protrusions, the lengths of the first fixing portion 15g and the third fixing portion 15m were each set to 8.1 mm, and the lengths of the second fixing portion 15h and the fourth fixing portion 15n were each set to 5.6 mm. The interval between the first fixing portion 15g and the second fixing portion 15h and the interval between the third fixing portion 15m and the fourth fixing portion 15n in one fixing portion row were each set to 2.0 mm. Adjacent first fixing portion rows 15A and adjacent second fixing portion rows 15B are formed such that wide and narrow portions alternately exist. The interval at the wide portion was 8.5 mm, and the interval at the narrow portion was 6.0 mm.
The area of the large projections 11ab in the first row of projections 11 is 90 mm ² , the area of the small projections 11as is 52 mm ² , and the middle projections 14 in the second row of projections 12 and the third row of projections 13 area was 70 mm ² .
The thickness of the large protrusions 11ab in the first protrusion row 11 is 1.90 mm, the thickness of the small protrusions 11as is 1.80 mm, and the middle protrusions in the second protrusion row 12 and the third protrusion row 13 The thickness of the portion 14 was 1.85 mm.

The nonwoven fabric 10 of this example was produced as follows. First, a fibrous web was produced by a carding method. A fibrous web was produced by mixing 50% by mass of each of the first fibers and the second fibers. The first fiber is a heat-extensible core-sheath type composite fiber (core is polypropylene, sheath is polyethylene) having a fineness of 3.3 dtex, and the ratio of the core to the sheath is 70% by mass. % by mass, and the sheath portion was 30% by mass. On the other hand, the second fiber is a heat-sealable core-sheath type composite fiber (core is polyethylene terephthalate, sheath is polyethylene) having a fineness of 2.4 dtex, and the ratio of the core to the sheath is the mass ratio. The fiber had a core portion of 50% by mass and a sheath portion of 50% by mass. Each of the first fibers and the second fibers was coated with a fiber treatment agent. The fiber treatment agent used contained other components in addition to the following components (A), (B) and (C). The composition of the fiber treatment agent and the amount of the fiber treatment agent adhered (100 percent (%) of the amount of the fiber treatment agent adhered per 1 g of the constituent fibers) are shown in Table 1 below.
(A) component: polyorganosiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., dimethyl silicone "KM-903")
(B) Component: Dialkyl sulfosuccinate sodium salt (manufactured by Kao Corporation, Pelex OT-P)
(C) Component: Alkyl (stearyl) betaine (manufactured by Kao Corporation, Amphithol 86B)
Other components: modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-22-4515")
Other ingredients: Phosphate ester type anionic surfactant: Potassium polyoxyethylene alkyl phosphate: Miyoshi Oil Co., Ltd.: Trade name "Annhorex MP-2K"

Next, the fiber web was arranged so that the embossing roll was in contact with the upper side and the flat roll was in contact with the lower side, and ultrasonic embossing was applied from the upper side of the fiber web. As the embossing roll, an engraved roll having convex portions corresponding to the fixed portions 15 shown in FIG. 2 formed on its peripheral surface was used. Finally, the fibrous web after embossing was subjected to air through processing at a hot air temperature of 136° C. and a processing speed of 10 m/min to obtain a nonwoven fabric 10 having a single layer structure. The basis weight of the obtained nonwoven fabric 10 was 28.0 g/m ² .

[Examples 2 and 3]
In Example 2, a sanitary napkin was produced in the same manner as in Example 1, except that the fiber treatment agent shown in Table 1 below was used.
In Example 3, a sanitary napkin was produced in the same manner as in Example 1, except that the thickness of each projection was changed and the fiber treatment agent shown in Table 1 below was used.

[Comparative Example 1]
A fiber web in Example 1 was produced, and ultrasonic embossing was applied to the fiber web from above. At this time, the fixed portions were formed so that the same convex portions were aligned in the planar direction to form the same convex portion pattern. Specifically, a pattern in which a plurality of rows of rhombic protrusions of the same shape and size are continuous in the vertical direction X is provided along the horizontal direction Y, and the rows are continuous in the vertical direction X and the horizontal direction Y. A fixed portion was formed. In the nonwoven fabric of Comparative Example 1, rhomboidal protrusions adjacent to each other in the longitudinal direction X and lateral direction Y were separated by the fixed portions. This rhombic projection had the same dimensions and shape as the small projections of Example 1. A sanitary napkin was manufactured in the same manner as in Example 3, except that such a nonwoven fabric was used as the surface sheet.

<Evaluation of remaining liquid amount on surface sheet>
The sanitary napkins obtained in Examples and Comparative Examples were placed on a flat table with the surface sheet facing upward. Next, the topsheet was once removed from the sanitary napkin, and the weight of the topsheet was weighed to obtain the initial weight (mass Wa (mg)) of the topsheet. The surface sheet was attached again to the sanitary napkin, and an acrylic injection plate integrally formed with a cylinder having a diameter of 10 mm and a height of 50 mm was placed so that the injection hole was positioned in the center of the surface sheet. placed. Under this condition, 3 g of defiberized horse blood was injected into the cylinder at once. After being left for 3 minutes after the injection, 3 g of defibrinated horse blood was injected again into the cylinder at once. One minute after injection, the injection plate was removed. Next, the topsheet was removed from the sanitary napkin, and the weight of the topsheet was weighed to obtain the weight of the topsheet after liquid absorption (mass Wb (mg)). The liquid residue amount (mg) of the topsheet was calculated by subtracting the mass Wa from the mass Wb. The smaller the value of the remaining amount of liquid, the less the liquid remains on the surface sheet, the better the dryness, and the better the touch after absorbing the liquid. Table 1 shows the results.

The defibrinated horse blood used in the above measurements was manufactured by Nihon Biotest Laboratory Co., Ltd. When the defibrinated horse blood is left to stand, the highly viscous portion (red blood cells, etc.) precipitates, and the low viscous portion (plasma) remains as a supernatant. The mixing ratio of those parts was adjusted so that the viscosity was 8.0 cP (25° C.). For the adjustment, a TVB10 viscometer manufactured by Toki Sangyo Co., Ltd. was used. The condition was 30 rpm.

<Evaluation of droplet absorption rate after washing with water>
The nonwoven fabrics of Examples and Comparative Examples were completely immersed in running water of 22°C in an environment of room temperature of 22°C and humidity of 65%, left in that state for 20 seconds, then taken out of the running water, squeezed by hand, and again in running water. A series of operations of complete immersion in water was repeated three times. After that, the nonwoven fabric was dried for 12 hours at a set temperature of 60°C using a hot air dryer. A sanitary napkin having a surface sheet of the washed and dried nonwoven fabric was produced. Such a sanitary napkin can be obtained by removing the surface sheet of a commercially available sanitary napkin (Laurier Skin Kirei Guard (registered trademark) with feathers for day use) with a cold spray, and attaching the nonwoven fabric after the washing and drying treatment there. made with Next, a drop of physiological saline (approximately 0.25 mL) is placed on the surface sheet of the sanitary napkin prepared using a micropipette. I observed until I could not confirm it. In such an operation, when the droplets remained on the surface sheet for 5 seconds or more, it was determined that "the droplets were not absorbed" (absorption amount of the droplets was 0 mL). In the above operation, droplets of physiological saline were dropped on ten different locations on the surface sheet. Then, the total absorption amount of the droplets absorbed by the sanitary napkin was calculated with respect to the total amount of droplets dropped onto the topsheet, and this was defined as the droplet absorption rate (%) after washing with water. It means that the higher the droplet absorption rate (%) after washing with water, the more excellent the durable hydrophilicity of the surface sheet. Table 1 shows the results.

As shown in Table 1, the absorbent article (sanitary napkin) of each example provided with a surface sheet (nonwoven fabric) having a pattern of large and small unevenness in FIG. Reduced liquid residue. In addition, the absorbent articles of each example had a higher liquid droplet absorption rate (%) after washing with water than the absorbent articles of the comparative examples. The results in Table 1 indicate that the absorbent article comprising the nonwoven fabric of the present invention can achieve both durable hydrophilicity and dryness.

REFERENCE SIGNS LIST 10 Non-woven fabric 11 First row of projections 11a First row of projections 11ab Large projections 11as Small projections 12 Second row of projections 12a Second projection 13 Third row of projections 13a Third projection 14 Middle projection 40 Upper layer 41 Thermal extensible fiber 50 Lower layer L1 Ridge line of first convex row S1 First high density region S2 Second high density region

Claims (6)

having a plurality of first projection rows extending in one direction,
The first projection row includes a large projection and a small projection having a smaller thickness and/or area than the large projection,
The large protrusions and the small protrusions are alternately arranged in the one direction and in a direction perpendicular to the one direction, respectively;
the degree of hydrophilicity of the small protrusions is higher than that of the large protrusions,
A nonwoven fabric for absorbent articles containing the following components (A) and (B).
(A) polyorganosiloxane (B) an anionic surfactant represented by the following formula (1)

(Wherein, Z represents an ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group, or a straight or branched hydrocarbon group having 1 to 12 carbon atoms, which may contain a double bond. , R ₁ and R ₂ each independently represent an ester group, an amide group, a polyoxyalkylene group, an ether group or a straight or branched alkyl group having 2 to 16 carbon atoms which may contain a double bond. X represents -SO ₃ M, -OSO ₃ M or -COOM, and M represents H, Na, K, Mg, Ca or ammonium.) a plurality of second projection rows and third projection rows extending in the one direction and positioned between the first projection rows;
Each of the second convex portion row and the third convex portion row includes a middle convex portion having a smaller thickness and/or area than the large convex portion,
The nonwoven fabric for absorbent articles according to claim 1, wherein the hydrophilicity of the small projections is higher than that of the middle projections, and the hydrophilicity of the middle projections is higher than that of the large projections. The nonwoven fabric for absorbent articles according to claim 1 or 2, further comprising the following component (C).
(C) Any amphoteric surfactant of sulfobetaine type, carbobetaine type and imidazoline type, which may have an amide bond in the hydrocarbon chain of the hydrophobic group. The nonwoven fabric for absorbent articles according to claim 3, wherein the component (C) is a carbobetaine-type amphoteric surfactant. The content ratio of the component (B) and the component (C) is 1:0.75 to 1:3 in mass ratio (B:C),
Claim 3 or wherein the content ratio of the component (A) to the total amount of the component (B) and the component (C) is 1:2 to 1:10 in mass ratio (A:B+C) 5. The nonwoven fabric for absorbent articles according to 4. An absorbent article comprising the nonwoven fabric for absorbent articles according to any one of claims 1 to 5.

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