Nonwoven fabric and method for producing the same

Abstract

The purpose of the present disclosure is to provide a nonwoven fabric that has embossed parts evenly arranged therein and that has excellent strength and flexibility. A nonwoven fabric according to the present disclosure has the following configuration.　A nonwoven fabric (1) comprises an embossed region (3) including a plurality of embossed parts (5) arranged evenly in the planar direction, and is characterized in that the plurality of embossed parts (5) in the embossed region (3) satisfy formula (1): 0.94≤(SMAX-SMIN) / SAVE≤2.50, when SMAX represents the maximum value of areas of the plurality of embossed parts (5), SMIN represents the minimum value of the areas of the plurality of embossed parts (5), and SAVE represents the average value of the areas of the plurality of embossed parts (5).

Description

Technical Field

[0001] The present disclosure relates to a nonwoven fabric and a method for manufacturing the nonwoven fabric.

Background Art

[0002] As an outer sheet of an absorbent article, a liquid-permeable sheet, etc., a nonwoven fabric formed by forming a plurality of embossed portions on a web, for example, a spunbond nonwoven fabric, is used. A spunbond nonwoven fabric is a nonwoven fabric that is excellent in productivity and also excellent in strength, air permeability, etc. On the other hand, from the viewpoint of ensuring strength, since it is necessary to arrange a plurality of embossed portions at a narrow pitch, the spunbond nonwoven fabric tends to be thin in thickness and inferior in flexibility.

[0003] To solve the problem, for example, Patent Document 1 discloses a nonwoven fabric having a plurality of embossed portions embossed over the entire surface, wherein the shortest distance from the boundary between the non-embossed portion of any embossed portion and the non-embossed portion of the four embossed portions adjacent to the nearer side of the arbitrary embossed portion to the boundary between the non-embossed portion of the arbitrary embossed portion is all 1.8 mm or more and less than 4.5 mm, and the area ratio of the crimped portion by the embossing to the total area of the nonwoven fabric is 8% or more and less than 14% (Claim 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The nonwoven fabric according to Patent Document 1 aims to improve the flexibility of the nonwoven fabric by setting the distance of the embossed portion and the area ratio of the squeezed portion within a specific range. However, the nonwoven fabric according to Patent Document 1 arranges embossed portions having a uniform shape regularly (for example, arranged in a staggered pattern), and due to the shape and arrangement of such embossed portions, the nonwoven fabric was inferior in flexibility. Therefore, an object of the present disclosure is to provide a nonwoven fabric in which embossed portions are regularly arranged and which is excellent in strength and flexibility.

Means for Solving the Problems

[0006] The present inventors have a nonwoven fabric provided with an embossed region including a plurality of embossed portions regularly arranged in a planar direction, where the maximum value of the individual areas of the plurality of embossed portions is S MAX Let, and the minimum value of the individual areas of the plurality of embossed portions be S MIN Let, and the average value of the individual areas of the plurality of embossed portions be S AVE When, the plurality of embossed portions in the embossed region satisfy the following formula (1): 0.94 ≦ (S MAX -S MIN ) / S AVE ≦ 2.50, and found a nonwoven fabric characterized by this.

Effects of the Invention

[0007] The nonwoven fabric according to the present disclosure has embossed portions regularly arranged and is excellent in strength and flexibility.

Brief Description of the Drawings

[0008]

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DETAILED DESCRIPTION OF THE INVENTION

[0009] Specifically, the present disclosure relates to the following aspects. [Aspect 1] A nonwoven fabric including an embossed region having a plurality of embossed portions regularly arranged in a planar direction, wherein the maximum value of the individual areas of the plurality of embossed portions is S MAX and the minimum value of the individual areas of the plurality of embossed portions is S MIN and the average value of the individual areas of the plurality of embossed portions is S AVE When, in the embossed region, the plurality of embossed portions satisfy the following formula (1): 0.94 ≦ (S MAX - S MIN ) / S AVE ≦ 2.50 Formula (1) satisfying characterized in that the nonwoven fabric.

[0010] In the nonwoven fabric, the plurality of embossed portions in the embossed region satisfy Formula (1). In Formula (1), S MINand an embossed portion having an area close thereto (hereinafter, may be referred to as "embossed portion in the vicinity of S"). In the embossed portion and its peripheral portion (hereinafter, may be referred to as "peripheral portion of the embossed portion"), the fibers constituting the nonwoven fabric are relatively weakly joined to the embossed portion, and the peripheral portion of the embossed portion is soft and tends to be deformed easily. Also, in the embossed portion having an area close to S MIN and its vicinity, the fibers constituting the nonwoven fabric in the peripheral portion of the embossed portion are relatively strongly joined to the embossed portion, and the strength of the peripheral portion of the embossed portion tends to be high. MAX When (S

[0011] - S MAX ) / S MIN satisfies the formula (1), the nonwoven fabric becomes excellent in strength and flexibility. AVE Note that when (S - S MAX ) / S MIN is less than 0.94, the difference between the soft and easily deformable portion of the nonwoven fabric and the portion with high strength becomes small, and the nonwoven fabric tends to be inferior in flexibility. Also, when (S AVE - S MAX ) / S MIN exceeds 2.50, the difference between the soft and easily deformable portion of the nonwoven fabric and the portion with high strength becomes too large, and the strength of the nonwoven fabric becomes low in the peripheral portion of the embossed portion in the embossed portion in the vicinity of S AVE , and the nonwoven fabric tends to be inferior in strength as a whole. MIN From the above, when a plurality of embossed portions in the embossed region satisfy the formula (1), the nonwoven fabric is excellent in strength and flexibility in the embossed region. The nonwoven fabric according to aspect 1, wherein the nonwoven fabric is for an outer wrapper sheet or a liquid-permeable sheet of an absorbent article.

[0012] [Aspect 2] Since the nonwoven fabric is for an outer wrapper sheet or a liquid-permeable sheet of an absorbent article, when used in an absorbent article, it can impart a certain strength to the absorbent article and the user can feel softness.

[0013] ​

[0014] [Aspect 3] When the coefficient of variation of the individual areas of the plurality of embossed portions is CV, the plurality of embossed portions in the embossed region satisfy the following formula (2): 10 ≦ CV ≦ 70 Formula (2) The nonwoven fabric according to Embodiment 1 or 2, which satisfies the above condition.

[0015] In the nonwoven fabric, since the plurality of embossed portions in the embossed region satisfy Formula (2), the individual areas of the plurality of embossed portions have a certain variation, and the effect of Embodiment 1 becomes higher.

[0016] [Aspect 4] The plurality of embossed portions in the embossed region satisfy the following formula (3): 0.09 ≦ S MIN / S AVE Formula (3) satisfies The nonwoven fabric according to any one of Embodiments 1 to 3.

[0017] In the nonwoven fabric, in the embossed region, the plurality of embossed portions in the embossed region satisfy Formula (3). By satisfying Formula (3), in the peripheral portion of the embossed portion of the embossed portion near S MIN the fibers constituting the nonwoven fabric are joined to the embossed portion with a certain strength, and the peripheral portion of the embossed portion tends to be soft and easily deformed.

[0018] In Formula (3), when S MIN / S AVE is less than 0.09, in the peripheral portion of the embossed portion of the embossed portion near S MIN the fibers constituting the nonwoven fabric are weakly joined to the embossed portion, and the nonwoven fabric tends to be inferior in strength. From the above, by the plurality of embossed portions in the embossed region satisfying Formula (3), the nonwoven fabric is excellent in strength in the embossed region.

[0019] [Aspect 5] Let the number of the plurality of embossed portions be N, and among the plurality of embossed portions, S AVE is the number of those having an area of 80% or more and 120% or less of 1 When N 0.26 ≦ N 1 / N ≦ 0.90 Formula (4) is satisfied, the nonwoven fabric according to any one of Aspects 1 to 4.

[0020] In the nonwoven fabric, the plurality of embossed portions in the embossed area satisfy Formula (3). By satisfying Formula (3), the plurality of embossed portions include, within a certain range, those having an area close to the average value (S AVE ), and the nonwoven fabric is excellent in the balance between strength and flexibility in the embossed area.

[0021] [Aspect 6] In the embossed area, the nonwoven fabric according to any one of Aspects 1 to 5, comprising a high basis weight area having a basis weight higher than the average basis weight of the nonwoven fabric and a low basis weight area having a basis weight lower than the average basis weight.

[0022] Since the nonwoven fabric has a high basis weight area and a low basis weight area in the embossed area, the nonwoven fabric is excellent in strength in the high basis weight area and excellent in flexibility in the low basis weight area in the embossed area.

[0023] [Aspect 7] When the average value of the individual areas of the plurality of embossed portions in the low basis weight area is SL AVE In the embossed area, the plurality of embossed portions satisfy the following formula (5): SL AVE < S AVE Formula (5) is satisfied, the nonwoven fabric according to Aspect 6.

[0024] In the nonwoven fabric, a plurality of embossed portions in the embossed region satisfy formula (5). By satisfying formula (5), the average value (SL AVE ) of the individual areas of the plurality of embossed portions in the low basis weight region AVE ) is less than the average value (S

[0025] [Aspect 8] When the average value of the individual areas of the plurality of embossed portions in the high basis weight region is SH AVE , the plurality of embossed portions in the embossed region satisfy the following formula (6): S AVE < SH AVE Formula (6) , The nonwoven fabric according to aspect 6 or 7.

[0026] In the nonwoven fabric, a plurality of embossed portions in the embossed region satisfy formula (6). By satisfying formula (6), the average value (SH AVE ) of the individual areas of the plurality of embossed portions in the high basis weight region AVE ) is greater than the average value (S

[0027] [Aspect 9] The nonwoven fabric according to any one of aspects 6 to 8, wherein the nonwoven fabric is composed of continuous fibers. Since the nonwoven fabric is composed of continuous fibers, a high basis weight region and a low basis weight region are directly connected by the continuous fibers. As a result, the nonwoven fabric is excellent in strength.

[0028] [Aspect 10] In the embossed region, the high basis weight region and the low basis weight region are each composed of a ridge portion protruding in one direction in the thickness direction of the nonwoven fabric and a groove portion recessed in the one direction. The nonwoven fabric according to Aspect 9, wherein the ridge portion further has a plurality of concave portions recessed in the one direction, and a base portion made of the continuous fibers is provided at the bottom of each of the plurality of concave portions.

[0029] Since the nonwoven fabric has a plurality of concave portions recessed in the thickness direction in the ridge portion formed from the high basis weight region, the area where the skin of the user using the nonwoven fabric touches the nonwoven fabric is smaller than that of a nonwoven fabric having no concave portions. Therefore, the nonwoven fabric can give the user a smooth touch. When the nonwoven fabric is applied to, for example, an absorbent article, for example, the outer wrapper sheet of a disposable diaper, and the surface provided with the plurality of ridge portions and the plurality of groove portions of the nonwoven fabric faces the non-skin side, the contact area of the surface of the nonwoven fabric is reduced by the amount of the concave portions, so that a smooth touch can be given. Further, since the nonwoven fabric has a complicated surface shape of a cloth pattern, a cloth pattern (woven fabric-like) texture can be imparted to the disposable diaper.

[0030] Also, when the nonwoven fabric is applied to, for example, an absorbent article, for example, the outer wrapper sheet of a disposable diaper, and the surface provided with the plurality of ridge portions and the plurality of groove portions of the nonwoven fabric faces the skin side, the space formed between the nonwoven fabric and the liquid-impermeable sheet further increases by the amount of the concave portions, so that it becomes difficult for moisture to be transmitted by clothing, sheets, etc.

[0031] When the nonwoven fabric is applied to, for example, a liquid-permeable sheet of an absorbent article, the base portion absorbs the excreted body fluid and easily suppresses the body fluid absorbed by the absorbent body from returning into the recess. Therefore, the nonwoven fabric is excellent in suppressing the feeling of wetness.

[0032] [Aspect 11] The planar direction includes a first direction and a second direction intersecting the first direction. The nonwoven fabric according to any one of Aspects 1 to 10, wherein the plurality of embossed portions are intermittently arranged at a first pitch in the first direction and intermittently arranged at a second pitch in the second direction.

[0033] Since the plurality of embossed portions are arranged in a predetermined arrangement in the nonwoven fabric, the effect of Aspect 1 is high.

[0034] [Aspect 12] The nonwoven fabric according to Aspect 11, wherein an intersection angle between the first direction and the second direction is 60 to 90°.

[0035] In the nonwoven fabric, since the intersection angle is within a predetermined range, the plurality of embossed portions tend to have a lattice shape close to a rectangle, and the nonwoven fabric tends to have a constant strength in any direction. On the other hand, in the nonwoven fabric, since the plurality of embossed portions satisfy at least Formula (1), the nonwoven fabric has flexibility. From the above, the nonwoven fabric is excellent in strength in any direction and excellent in flexibility.

[0036] [Aspect 13] The nonwoven fabric according to Aspect 11 or 12, wherein the first pitch and the second pitch are the same.

[0037] In the nonwoven fabric, since the first pitch and the second pitch are the same, the plurality of embossed portions tend to have a lattice shape close to a square, and the nonwoven fabric tends to have a more constant strength in any direction. On the other hand, in the nonwoven fabric, since the plurality of embossed portions satisfy at least Formula (1), the nonwoven fabric has flexibility. As described above, the nonwoven fabric is excellent in strength in any direction and excellent in flexibility.

[0038] [Aspect 14] A method for manufacturing the nonwoven fabric according to any one of Aspects 6 to 10, preparing a web including the high basis weight region and the low basis weight region, forming the plurality of embossed portions on the web using a pair of embossing rolls including an embossing roll having a plurality of protrusions and an anvil roll to form the nonwoven fabric, including each of the plurality of protrusions having the same squeezing area, the method being characterized by this.

[0039] The above manufacturing method can manufacture the nonwoven fabric according to any one of Aspects 6 to 10. Further, in the above manufacturing method, since each of the plurality of protrusions has the same squeezing area, the pressure applied to the web from the plurality of protrusions is likely to be uniform in the conveyance direction and the transverse direction of the embossing roll, so that a nonwoven fabric excellent in strength and flexibility can be accurately formed.

[0040] The nonwoven fabric and the method for manufacturing the nonwoven fabric of the present disclosure will be described in detail below. [Nonwoven Fabric] The nonwoven fabric according to the present disclosure includes an embossed region including a plurality of embossed portions regularly arranged in the planar direction. The planar direction means the direction in which the nonwoven fabric spreads. The regular arrangement will be described later.

[0041] In the nonwoven fabric of the present disclosure, when the maximum value of the individual areas of the plurality of embossed portions is S MAX and the minimum value of the individual areas of the plurality of embossed portions is S MIN and the average value of the individual areas of the plurality of embossed portions is S AVE the plurality of embossed portions in the embossed region satisfy the following formula (1): 0.94≦(SMAX -S MIN ) / S AVE ≤2.50 Formula (1) is satisfied. Thereby, the nonwoven fabric is excellent in strength and flexibility.

[0042] (S MAX -S MIN ) / S AVE is preferably 0.94 or more, more preferably 0.96 or more, and even more preferably 0.97 or more. Thereby, it becomes easy to secure the difference between the soft and easily deformable part of the nonwoven fabric and the high-strength part. (S MAX -S MIN ) / S AVE is preferably 2.20 or less, more preferably 2.00 or less, and even more preferably 1.80 or less. Thereby, the difference between the soft and easily deformable part of the nonwoven fabric and the high-strength part can be within a certain range.

[0043] In addition, in this specification, the measurement method of the individual areas of a plurality of embossed portions, as well as the maximum value (S MAX ) of the individual areas of a plurality of embossed portions, the minimum value (S MIN ) of the individual areas of a plurality of embossed portions, and the average value (S AVE ) of the individual areas of a plurality of embossed portions (hereinafter, may be referred to as "measurement method of the area of the embossed portion") is as follows. (1) Temperature: Prepare a VHX-7000 (lens: E30) manufactured by KEYENCE in a thermostatic and humidistatic chamber adjusted to 20°C and humidity: 60%RH. (2) Cut the nonwoven fabric into a size of 100 mm × 100 mm, prepare a sample, and leave the sample in the above thermostatic and humidistatic chamber for 24 hours. (3) Place the sample on the stage of the VHX-7000.

[0044] (4) Take images of a plurality of embossed portions under the following conditions. · Magnification: 30 times · Episcopic illumination: Off (Ring illumination) · Tilt angle: 0° · Support plate: Glass support plate (5) Select "Measurement Scale", "Plane Measurement", and "Area Measurement" on the menu screen, and in the "Free Line" setting, trace the part where multiple fibers are crushed to extract the shape of the embossed part. (6) Let the VHX-7000 measure the area of the extracted part of the embossed part. (7) Measure the area of 100 embossed parts in total, and calculate S MAX , S MIN and S AVE .

[0045] In the nonwoven fabric according to the present disclosure, when the coefficient of variation of the individual areas of a plurality of embossed parts is CV, the plurality of embossed parts in the embossed area satisfy the following formula (2): 10 ≤ CV ≤ 70 Formula (2) It is preferably satisfied. Thereby, the nonwoven fabric is excellent in strength and flexibility.

[0046] CV is preferably 14 or more, more preferably 17 or more, and even more preferably 20 or more. Thereby, also, CV is preferably 60 or less, more preferably 55 or less, and even more preferably 50 or less. Thereby, the nonwoven fabric is excellent in strength and flexibility. Note that CV means CV (%), which is calculated by dividing the standard deviation of the individual areas of a plurality of embossed parts in the embossed area by the average value (S AVE ) of the individual areas of the plurality of embossed parts and multiplying by 100 to convert it into a percentage.

[0047] In the nonwoven fabric according to the present disclosure, the plurality of embossed parts in the embossed area satisfy the following formula (3): 0.09 ≤ S MIN / S AVE Formula (3) It is preferably satisfied. Thereby, the nonwoven fabric is excellent in strength in the embossed area. Note that S MINIn the peripheral part of the embossed part of the nearby embossed part, the strength of the nonwoven fabric becomes low, and the nonwoven fabric tends to be inferior in strength as a whole.

[0048] S MIN / S AVE is preferably 0.12 or more, more preferably 0.14 or more, and still more preferably 0.16 or more. Also, S MIN / S AVE is preferably 0.7 or less, more preferably 0.6 or less, and still more preferably 0.5 or less. Thereby, the nonwoven fabric is excellent in strength in the embossed area.

[0049] In the nonwoven fabric according to the present disclosure, the number of the plurality of embossed parts is N, and among the plurality of embossed parts, S AVE having an area of 80% or more and 120% or less of the number of N 1 When it is set as, the plurality of embossed parts in the embossed area are the following formula (4): 0.26≦N 1 / N≦0.90 Formula (4) It is preferable to satisfy. Thereby, the nonwoven fabric is excellent in the balance between strength and flexibility in the embossed area.

[0050] N 1 / N is preferably 0.30 or more, more preferably 0.35 or more, and still more preferably 0.40 or more. Also, N 1 / N is preferably 0.88 or less, more preferably 0.86 or less, and still more preferably 0.84 or less. Thereby, the nonwoven fabric is excellent in the balance between strength and flexibility in the embossed area. Note that N can be determined by measuring the number of embossed parts in the embossed area, and N 1 is in the embossed area, S AVE It can be determined by measuring the number of embossed parts having an area of 80% or more and 120% or less.

[0051] The nonwoven fabric according to the present disclosure preferably includes, in the embossed region, a high basis weight region having a basis weight higher than the average basis weight of the nonwoven fabric and a low basis weight region having a basis weight lower than the average basis weight. Thereby, in the embossed region, the nonwoven fabric is excellent in strength in the high basis weight region and excellent in flexibility in the low basis weight region. Examples of the nonwoven fabric including the high basis weight region and the low basis weight region include those known in the art.

[0052] In the nonwoven fabric according to the present disclosure, when the average value of the individual areas of the plurality of embossed portions in the low basis weight region is SL AVE it is preferable that the plurality of embossed portions in the embossed region satisfy the following formula (5): SL AVE <S AVE Formula (5) Thereby, the nonwoven fabric is excellent in flexibility in the embossed region and the low basis weight region.

[0053] Note that the average value of the individual areas of the plurality of embossed portions in the low basis weight region: SL AVE and the average value of the individual areas of the plurality of embossed portions: S AVE can be evaluated visually. Further, the above magnitude can be determined by measuring the average value (SL AVE ) of the individual areas of the plurality of embossed portions in the low basis weight region using the above-mentioned "method for measuring the area of the embossed portion" and comparing it with the average value (S AVE ) of the individual areas of the plurality of embossed portions.

[0054] In the nonwoven fabric according to the present disclosure, when the average value of the individual areas of the plurality of embossed portions in the high basis weight region is SH AVE it is preferable that the plurality of embossed portions in the embossed region satisfy the following formula (6): S AVE <SH AVE Formula (6) Thereby, the nonwoven fabric is excellent in strength in the embossed region and the high basis weight region. ​​

[0055] In addition, the average value of the individual areas of the plurality of embossed portions in the high flatness amount region: SH AVE and the average value of the individual areas of the plurality of embossed portions: S AVE The magnitude relationship therebetween can be evaluated visually. Further, the above magnitude relationship can be determined by measuring the average value (SH AVE ) of the individual areas of the plurality of embossed portions in the high flatness amount region using the above-mentioned "method for measuring the area of the embossed portion" and comparing it with the average value (S AVE ) of the individual areas of the plurality of embossed portions.

[0056] The nonwoven fabric according to the present disclosure is not particularly limited as long as it includes a plurality of embossed portions, and examples thereof include a spunbond nonwoven fabric, a spunbond / meltblown / spunbond nonwoven fabric (SMS nonwoven fabric), a point bond nonwoven fabric, and the like.

[0057] The fibers constituting the nonwoven fabric according to the present disclosure include heat-fusible fibers. Examples of the heat-fusible fibers include polyolefin-based single fibers such as polyethylene, polypropylene, and polyvinyl alcohol, core-sheath type composite fibers including olefin-based resins such as polyethylene terephthalate (core) / polyethylene (sheath), polyethylene terephthalate (core) / polypropylene (sheath), and polypropylene (core) / polyethylene (sheath). Further, the heat-fusible fibers may be biodegradable fibers such as polylactic acid, polyglycol, polyhydroxybutyrate, polybutylene succinate, polybutylene succinate / adipate, and polycaprolactone.

[0058] The composite fibers may be hydrophobic fibers or may be those subjected to a hydrophilization treatment with a hydrophilic oil agent or the like. The hydrophilization treatment can be performed, for example, by kneading a hydrophilizing agent into the resin constituting the fibers, applying a hydrophilizing agent to the surface of the fibers, or the like. Further, as the composite fibers, side-by-side type fibers including the above-mentioned olefin-based resins may be used. These fibers may be used alone or in combination of two or more kinds of fibers. Furthermore, the above fibers are preferably composed of continuous fibers. Thereby, the nonwoven fabric is excellent in strength.

[0059] When the nonwoven fabric according to the present disclosure has a high basis weight region and a low basis weight region in the embossed region, the high basis weight region and the low basis weight region are each composed of a ridge portion protruding in one direction in the thickness direction of the nonwoven fabric and a groove portion recessed in the other direction, and the ridge portion preferably further has a plurality of recesses recessed in the above one direction, and a base portion made of continuous fibers is provided at the bottom of each of the plurality of recesses. Thereby, it is possible to give the user a smooth touch feeling, excellent in suppressing the feeling of wetness, to impart a texture for fabrics, and to make it difficult to transmit moisture through clothing, sheets, etc.

[0060] In the nonwoven fabric according to the present disclosure, "regularly arranged in the planar direction" regarding the plurality of embossed portions means that the planar direction includes a first direction, and the plurality of embossed portions are regularly arranged at least in the first direction.

[0061] Also, in the nonwoven fabric according to the present disclosure, the planar direction includes a first direction and a second direction intersecting the first direction, and the plurality of embossed portions are preferably regularly arranged in the first direction and the second direction, and are more preferably intermittently arranged at a first pitch in the first direction and intermittently arranged at a second pitch in the second direction. Thereby, the nonwoven fabric is likely to be excellent in strength. Note that the first direction means the direction in which the distance between the embossed portions is the shortest among the plurality of embossed portions, and the second direction means the direction in which the distance between the embossed portions is the shortest in a direction different from the first direction.

[0062] In the nonwoven fabric according to the present disclosure, when a plurality of embossed portions are regularly arranged in a first direction and a second direction, the crossing angle formed by the first direction and the second direction is greater than 0° and less than or equal to 90°. The crossing angle is preferably 30° or more, more preferably 45° or more, still more preferably 60° or more, and even more preferably 75° or more. Thereby, the nonwoven fabric is likely to have a certain strength in any direction.

[0063] In the nonwoven fabric according to the present disclosure, when a plurality of embossed portions are intermittently arranged at a first pitch in a first direction and intermittently arranged at a second pitch in a second direction, the first pitch and the second pitch may be the same or different. By the first pitch and the second pitch being the same, the plurality of embossed portions are likely to take a lattice shape close to a square, and the nonwoven fabric is likely to have a more constant strength in any direction.

[0064] The outer shape, various dimensions, average basis weight, etc. of the nonwoven fabric according to the present disclosure vary depending on the use of the nonwoven fabric. For example, when the nonwoven fabric is used for an absorbent article, the average basis weight of the nonwoven fabric is, for example, 8 to 80 g / m 2 is.

[0065] In this specification, the average basis weight of the nonwoven fabric: BW (g / m 2 ) is measured by the following method. (1) Cut out 5 samples of a predetermined size (example: 100 mm × 100 mm) from the nonwoven fabric. (2) Measure the mass of the 5 cut-out samples with a direct-reading balance (example: electronic balance HF-300 manufactured by Ken Seiko Kogyo Co., Ltd.). (3) Calculate the mass per unit area of the nonwoven fabric from the average value of the masses of the 5 samples, and set it as the average basis weight of the nonwoven fabric: BW (g / m 2 ).

[0066] The average thickness of the nonwoven fabric varies depending on the use of the nonwoven fabric. For example, when the nonwoven fabric is used for an absorbent article, the average thickness of the nonwoven fabric is, for example, 0.1 mm to 3 mm. The average thickness of the nonwoven fabric is measured by FS-60DS manufactured by Eiwa Scientific Instrument Co., Ltd. [measurement surface: 50.5 mm (diameter), measurement pressure: 3 gf / cm 2 (0.3 kPa)] under standard conditions (temperature: 23 ± 2°C, relative humidity: 50 ± 5%), by pressing five different parts of the nonwoven fabric and measuring the average value of five measured values of the thickness 10 seconds after pressing at each part.

[0067] The nonwoven fabric according to the present disclosure is measured using an automated compression tester, KES-FB3-A manufactured by Kato Tech Co., Ltd., with an initial thickness of T 0 (mm) and a compressed thickness of T m (mm), and the difference "T 0 -T m " (mm) is divided by the average basis weight of the nonwoven fabric: BW (g / m 2 ), and the compression characteristics per unit basis weight: (T 0 -T m ) / BW [mm / (g / m 2 )] is preferably 0.010 or more, more preferably 0.011 or more, and even more preferably 0.012 or more. Also, the compression characteristics per unit basis weight: (T 0 -T m ) / BW [mm / (g / m 2 )] is preferably 0.030 or less, more preferably 0.025 or less, and even more preferably 0.020 or less. Thereby, when the user touches the nonwoven fabric, the nonwoven fabric is easily deformed in the thickness direction and has excellent flexibility.

[0068] The measurement conditions of the initial thickness: T 0 (mm) and the compressed thickness: T m (mm) using an automated compression tester, KES-FB3-A manufactured by Kato Tech Co., Ltd. are as follows. SENS: 2 Speed: 0.02 mm / second Stroke: 5 mm / 10 V Pressing area: 2 cm 2 Sampling interval: 0.1 second Upper limit load: 50 g / cm 2 Number of repetitions: 1 time

[0069] Incidentally, the initial thickness: T 0 (mm) represents the thickness of the nonwoven fabric when pressed at a pressure of 0.05 kPa (0.5 gf / cm 2 ), and the thickness during compression: T m (mm) represents the thickness of the nonwoven fabric when pressed at a pressure of 4.9 kPa (50 gf / cm 2 ).

[0070] The bending rigidity value: B (10 -4 mN×m 2 / m) of the nonwoven fabric according to the present disclosure is a value obtained by dividing the bending rigidity value by the average basis weight: BW of the nonwoven fabric and the initial thickness: T 0 (mm) of the nonwoven fabric, that is, the bending rigidity per unit basis weight and unit thickness: B / BW / T 0 [(10 -4 mN×m 2 / m) / (g / m 2 ) / mm] is preferably 0.5 or more, more preferably 1.0 or more, and still more preferably 1.2 or more. Also, the bending rigidity per unit basis weight and unit thickness: B / BW / T 0 [(10 -4 mN×m 2 / m) / (g / m 2 ) / mm] is preferably less than 2.7, more preferably 2.5 or less, and still more preferably 2.3 or less. Thereby, the nonwoven fabric is easily deformed when a force is applied and has excellent flexibility.

[0071] The measurement conditions of the bending rigidity value: B (10 -4 mN×m 2 / m) using the pure bending tester KES-FB2-A manufactured by Kato Tech Co., Ltd. are as follows. SENS: 20 Maximum curvature: ±2.5 Sample width: 100 mm Number of repetitions: 1 time

[0072] Note that the bending rigidity value: B is calculated between a curvature of 0.5 and 1.5. Also, the bending direction is implemented under the condition that the fold is folded back in the MD direction so that the fold is parallel to the CD direction of the sample. For the bending rigidity value: B, the average value with n = 5 is adopted.

[0073] The bending rigidity value: B means that as the value becomes smaller, it becomes easier to bend and deform. When a nonwoven fabric with a small bending rigidity value: B is used, for example, as the outer sheet of an absorbent article, the nonwoven fabric easily deforms when the surface is touched, and the nonwoven fabric follows the movement of the fingertips, so it feels soft and is easy to feel.

[0074] Note that the bending rigidity value: B is divided by the average basis weight: BW of the nonwoven fabric and the initial thickness: T 0 (mm) to obtain the bending rigidity per unit basis weight and unit thickness: B / BW / T 0 [(10 -4 mN×m 2 / m) / (g / m 2 ) / mm] is evaluated because the bending rigidity value: B tends to increase as the average basis weight of the nonwoven fabric increases and also tends to increase as the thickness of the nonwoven fabric increases.

[0075] For the nonwoven fabric according to the present disclosure, the breaking strength: BR (N / 50 mm) is divided by the average basis weight: BW (g / m 2 ) to calculate the breaking strength per unit basis weight: BR / BW [(N / 50 mm) / (g / m 2 )], which is preferably 0.70 or more, more preferably 0.75 or more, and even more preferably 0.80 or more. Also, the breaking strength per unit basis weight: BR / BW [(N / 50 mm) / (g / m 2 )] is preferably 2.00 or less, more preferably 1.70 or less, and even more preferably 1.50 or less. Thereby, the nonwoven fabric is excellent in strength.

[0076] The breaking strength: BR is measured as follows. (1) Prepare an autograph, AG-1, manufactured by Shimadzu Corporation. Prepare five samples with a size of 150 mm in the cross - direction CD and 50 mm in the conveying direction MD during manufacturing. Measure the breaking strength in the cross - direction CD at a chuck distance of 100 mm and a tensile speed of 100 mm / min.

[0077] Adopt the average value of the breaking strength of the five samples as the breaking strength: BR (N / 50 mm). Note that "N / 50 mm" means the breaking strength (N) per 50 - mm width, and the breaking strength means the strength at the maximum point load.

[0078] The non - woven fabric according to the present disclosure is not particularly limited and can be used for various applications. For example, it can be used for absorbent articles such as disposable diapers, urine pads, urination sheets for animals, sanitary napkins, panty liners, etc. In addition, the non - woven fabric according to the present disclosure can be used for the outer packaging sheet and liquid - permeable sheet of absorbent articles.

[0079] FIG. 1 is a diagram for explaining a spunbond non - woven fabric 1 according to one embodiment of the present disclosure (hereinafter referred to as "the first embodiment"). The spunbond non - woven fabric 1 according to the first embodiment has a plane direction PD including a first direction D 1 and a second direction D 1 orthogonal to the first direction D. 2 The spunbond non - woven fabric 1 has a plane direction PD including a first direction D and a second direction D orthogonal to the first direction D. The spunbond non - woven fabric 1 includes a plurality of high - basis - weight regions 11 extending in a predetermined direction D and a plurality of low - basis - weight regions 13 extending in the predetermined direction D. Each of the plurality of high - basis - weight regions 11 and the plurality of low - basis - weight regions 13 are alternately arranged in a direction orthogonal to the predetermined direction D.

[0080] The spunbond non - woven fabric 1 includes an embossed region 3 having a plurality of embossed portions 5. The plurality of embossed portions 5 are intermittently arranged at a first pitch P 1 in the first direction D 1 and are intermittently arranged at a second pitch P 2 in the second direction D. 2 The plurality of embossed portions 5 are intermittently arranged at a first pitch P in the first direction D and at a second pitch P in the second direction D.

[0081] The plurality of embossed portions 5 can be partitioned into a plurality of first embossed portions 7 arranged in the plurality of high basis weight regions 11 and a plurality of second embossed portions 9 arranged in the plurality of low basis weight regions 13, and the area of each of the plurality of first embossed portions 7 tends to be larger than the area of each of the plurality of second embossed portions 9.

[0082] By alternately arranging the plurality of first embossed portions 7 with a large embossed portion area and a large amount of fibers to be joined, and the plurality of second embossed portions 9 with a small embossed portion area and a small amount of fibers to be joined, in a direction orthogonal to the predetermined direction D, regions with a small embossed portion area and easy to deform are arranged at regular intervals, resulting in a non-woven fabric that is easy to deform and has excellent flexibility.

[0083] In addition, since portions with a large embossed portion area and high strength are also arranged at regular intervals, when used for the outer packaging sheet of an absorbent article, etc., a non-woven fabric that is difficult to tear during wearing and has high durability can be obtained. Furthermore, since regions with a large embossed portion area and a large amount of fibers are continuously arranged in a certain direction, a non-woven fabric that is difficult to enter the width during the manufacture of the absorbent article and has excellent manufacturing stability can be obtained.

[0084] The spunbond non-woven fabric 1 can be applied to an absorbent article, for example, the outer packaging sheet of a disposable diaper. In the spunbond non-woven fabric 1, the structure of the web 51 constituting the spunbond non-woven fabric 1 remains in the portions separated from each of the plurality of embossed portions 5. By the structure of the web 51 remaining in the spunbond non-woven fabric 1, the following effects are obtained.

[0085] In the portions separated from each of the plurality of embossed portions 5, each of the plurality of high basis weight regions 11 has a ridge portion 53 (see FIG. 2), each of the plurality of low basis weight regions 13 has a groove portion 55 (see FIG. 2), and the ridge portions (see FIG. 2) formed by the plurality of high basis weight regions 11 have a plurality of concave portions 57 (see FIG. 2). In the description of the spunbond nonwoven fabric 1, some of the reference signs are those of the web 51 shown in FIG. 2. Also, a predetermined direction D in the spunbond nonwoven fabric 1 is parallel to the first direction x in FIG. 2.

[0086] Since the ridges 53 of the plurality of high basis weight regions 11 have a larger basis weight than the grooves 55 of the plurality of low basis weight regions 13, when a load is applied in the thickness direction z (see FIG. 2), the thickness of the ridges 53 is less likely to change. Then, since the length of the ridges 53 in the second direction y (see FIG. 2) is also less likely to change, the length of the grooves 55 in the second direction y is less likely to change.

[0087] Therefore, when the spunbond nonwoven fabric 1 is used as an outer sheet such that the surface provided with the plurality of ridges 53 and the plurality of grooves 55 faces the non-skin side (outer surface side), even when a load is applied over time during wearing, the plurality of ridges 53 are less likely to collapse, and since they have the recesses 57, the contact area of the surface of the spunbond nonwoven fabric 1 can be reduced, and a crisp touch can be given to the user. Also, since the spunbond nonwoven fabric 1 has a complex surface shape like a fabric pattern, a fabric (woven fabric-like) texture can be imparted to the disposable diaper. Also, in this case, in the disposable diaper, patterns provided on an indicator, a liquid-impermeable sheet, etc. can be clearly visible from the outer sheet side through the plurality of grooves 55.

[0088] Also, when the spunbond nonwoven fabric 1 is used as an outer sheet such that the surface provided with the plurality of ridges 53 and the plurality of grooves 55 faces the skin side (inner surface side), since the plurality of ridges 53 are less likely to collapse, a space derived from the plurality of grooves 55 and the recesses 57 is formed between the spunbond nonwoven fabric 1 and the liquid-impermeable sheet, so it is difficult for moisture in the absorbent article to be transmitted to clothing, sheets, etc. Also, in this case, in the disposable diaper, patterns provided on an indicator, a liquid-impermeable sheet, etc. can be clearly visible from the outer sheet side through the plurality of grooves 55.

[0089] The spunbond nonwoven fabric 1 can be applied to absorbent articles, for example, the liquid-permeable sheet of disposable diapers. In the spunbond nonwoven fabric 1, in the portions separated from each of the plurality of embossed portions 5, the structure of the web 51 constituting the spunbond nonwoven fabric 1 remains. By the structure of the web 51 remaining in the spunbond nonwoven fabric 1, the following operational effects can be obtained.

[0090] The spunbond nonwoven fabric 1 (liquid-permeable sheet) has a plurality of ridge portions 53 and a plurality of groove portions 55 alternately provided in the second direction y, so that in a wide range in the first direction x and the second direction y, the distance between the absorbent body and the user's skin is maintained and it is excellent in suppressing a wet feeling, and the visibility of the body fluid absorbed by the absorbent body through the plurality of groove portions 55 is excellent.

[0091] The spunbond nonwoven fabric 1 (liquid-permeable sheet) has a plurality of groove portions 55 and a plurality of recesses 57 (see FIG. 2) recessed in the thickness direction z in the plurality of ridge portions 53. Therefore, the area of the surface of the spunbond nonwoven fabric 1 that the user's skin touches when it is wet is smaller than that of the spunbond nonwoven fabric 1 without the recesses 57. In the spunbond nonwoven fabric 1 (liquid-permeable sheet), the base portion 59 (see FIG. 2) absorbs the excreted body fluid and more surely suppresses the body fluid absorbed by the absorbent body from returning into the recesses 57.

[0092] In the spunbond nonwoven fabric 1 (liquid-permeable sheet), each of the plurality of ridge portions 53 has a bundle portion 61 (see FIG. 2) in which continuous fibers are oriented along the first direction x (see FIG. 2) on one side in the second direction y of at least a part of the plurality of recesses 57. In the bundle portion 61, the fiber distance between the continuous fibers is small and it is difficult to deform when receiving a load. Therefore, the spunbond nonwoven fabric 1 (liquid-permeable sheet) having the bundle portion 61 is likely to maintain the shape of the recess with little change in thickness during wearing. As a result, the spunbond nonwoven fabric 1 (liquid-permeable sheet) is likely to maintain the state of keeping the distance between the absorbent body and the user's skin, and is also likely to maintain the shape of the recesses 57. Therefore, it is easy to maintain the state where the area of contact with the spunbond nonwoven fabric 1 (liquid-permeable sheet) is small.

[0093] In the spunbond nonwoven fabric 1, since the thickness of each of the plurality of groove portions 55 is thinner than the thickness of the base portion 59, the plurality of groove portions 55 are excellent in visibility in the thickness direction z, and the difference from the plurality of ridge portions 53 in which visibility in the thickness direction z is hardly obtained is prominent. Therefore, the spunbond nonwoven fabric 1 (liquid-permeable sheet) is excellent in visibility.

[0094] In the spunbond nonwoven fabric 1 (liquid-permeable sheet), each of the plurality of ridge portions 53 of the spunbond nonwoven fabric 1 protrudes toward each of the plurality of groove portions 55 adjacent thereto and has a plurality of protruding portions 63 (see FIG. 2) arranged at intervals along the first direction x. Therefore, when a load is applied in the thickness direction z, the plurality of ridge portions 53 are difficult to fall down. Therefore, the liquid-permeable sheet easily maintains a state in which the plurality of ridge portions 53 maintain their shapes, so the plurality of ridge portions 53 are difficult to block the groove portions 55, and thus the visibility is excellent.

[0095] In the spunbond nonwoven fabric 1 (liquid-permeable sheet), the fiber orientation along the first direction x of the plurality of ridge portions 53 of the spunbond nonwoven fabric 1 is higher than the fiber orientation along the first direction x of the plurality of groove portions 55, so the distance between the intersections of the continuous fibers is short. Therefore, the shape of the plurality of ridge portions 53 of the spunbond nonwoven fabric 1 is easily maintained. Also, body fluid can be diffused in the first direction x along the plurality of ridge portions 53. Therefore, the liquid-permeable sheet suppresses the retention of body fluid at one place by diffusing the body fluid in the first direction Lx, and thus is excellent in suppressing the feeling of wetness. Also, since the fiber orientation along the first direction x of the plurality of ridge portions 53 of the liquid-permeable sheet is higher, the distance between the intersections of the continuous fibers is short and the distance between the plurality of joint portions is short, so the shape is easily maintained. Therefore, the liquid-permeable sheet is difficult to deform in the thickness direction z.

[0096] When forming the web 51 of the spunbond nonwoven fabric 1, although the continuous fibers are moved by an air current, because of their long fiber length, they move over a certain length and further move along with adjacent continuous fibers, so they are easily affected by the air current in the deposition process. Therefore, when each of the continuous fibers moves, a portion with a small fiber distance is likely to be formed. The continuous fibers have a short distance between their intersections with each other and a short distance between a plurality of joints. Therefore, the spunbond nonwoven fabric 1 (liquid-permeable sheet) is likely to maintain the shape of the plurality of ridge portions 53.

[0097] When a load is applied in the thickness direction z during wearing, the plurality of ridge portions 53 of the spunbond nonwoven fabric 1 are not easily collapsed, and the length in the second direction y of the plurality of groove portions 55 is maintained in a state where the basis weight is small.

[0098] [Method for manufacturing nonwoven fabric] The method for manufacturing a nonwoven fabric according to the present disclosure has the following configuration. · A step of preparing a web including a high basis weight region and a low basis weight region (hereinafter, may be referred to as "web preparation step") A step of forming a plurality of embossed portions on the web using a pair of embossing rolls including an embossing roll having a plurality of protrusions and an anvil roll to form the nonwoven fabric (hereinafter, may be referred to as "nonwoven fabric forming step") Hereinafter, it will be described along a specific embodiment.

[0099] The spunbond nonwoven fabric 1 according to the first embodiment can be manufactured as follows. [Web preparation step] A resin composition is spun from a spinning nozzle, the spun long fiber filaments are cooled by a cooling fluid or the like, and a tension is applied to the long fiber filaments by stretching air to form continuous fibers having a predetermined fineness. The obtained continuous fibers are deposited on the wire mesh 101 while being sucked from below the wire mesh 101 moving in the conveyance direction MD to form the web 51.

[0100] A perspective view of the formed web 51 is shown in FIG. 2, and a cross section in the y direction of FIG. 2 is shown in FIG. 3. Further, a perspective view schematically showing the wire mesh 101 is shown in FIG. 4, and an end view in the transverse direction CD of the wire mesh 101 is shown in FIG. 5.

[0101] As shown in FIG. 2, the web 51 has a first direction x, a second direction y, and a thickness direction z that are perpendicular to each other, and is composed of continuous fibers. Thereby, the ends of the continuous fibers are less likely to exist on the surface of the web 51, and thus the nonwoven fabric 1, resulting in an excellent wearing feeling.

[0102] The web 51 includes a plurality of ridge portions 53 and a plurality of groove portions 55. The plurality of ridge portions 53 and the plurality of groove portions 55 are provided on one surface in the thickness direction z of the web 51, the upper surface in the case of FIG. 2. The plurality of ridge portions 53 protrude from one surface in the thickness direction z of the web 51 and extend along the first direction x. The plurality of groove portions 55 extend along the first direction x and have a lower basis weight than the plurality of ridge portions 53. Each of the plurality of ridge portions 53 and each of the plurality of groove portions 55 are alternately provided in the second direction y. The plurality of ridge portions 53 are arranged at a predetermined interval in the second direction y.

[0103] Each of the plurality of ridge portions 53 has a larger amount of continuous fibers and is thicker than the thickness of each of the plurality of groove portions 55. That is, the thickness of each of the plurality of groove portions 55 is thinner than the thickness of each of the plurality of ridge portions 53. The plurality of ridge portions 53 and the plurality of groove portions 55 are connected by a smooth surface. As shown in FIG. 3, the plurality of ridge portions 53 and the plurality of groove portions 55 are at the 50% thickness T of the thickness Tn of the web 51 in the unloaded state. 50 Taking this as a boundary, the region having a thickness of 50% or more of the thickness Tn is defined as the ridge portion 53, and the region having a thickness of less than 50% of the thickness Tn is defined as the groove portion 55.

[0104] It is preferable that the fiber orientation along the first direction x of the plurality of ridge portions 53 is higher than the fiber orientation along the first direction x of the plurality of groove portions 55. Since the fiber orientation along the first direction x of the plurality of ridge portions 53 is higher, the distance between intersections of continuous fibers is short and the distance between the plurality of joint portions is short, so that the shape of the web 51, and thus the spunbond nonwoven fabric 1, is easily maintained. Fiber orientation is a concept consisting of the orientation angle and orientation strength of fibers and can be measured, for example, by the following method.

[0105] The web 51 or the nonwoven fabric 1 is left standing so that the surface on which the plurality of ridge portions 53 and the plurality of groove portions 55 are formed is located on the upper side. Using a microscope (for example, a scanning electron microscope such as JCM-5100 manufactured by JEOL Ltd.), a magnified image is taken from a direction perpendicular to the measurement surface of the web 51 or the nonwoven fabric 1, printed, and the fibers are traced on a transparent PET sheet. The magnified image is an image magnified to a magnification at which 10 or more fibers can be measured, and the magnification is, for example, 50 to 300 times. The image is imported into a personal computer, and the image is binarized using nexusNewQube (stand-alone version) image processing software manufactured by Nexus Co., Ltd. Using Fiber Orientation Analysis 8.13 Single, which is a fiber orientation analysis program, the orientation angle and orientation strength are obtained from the binarized image. The orientation angle is the angle at which the fibers are most oriented, and the orientation strength is the strength at that orientation angle. The measurement is repeated several times (for example, 3 to 5 times), and the average value is calculated.

[0106] Each of the plurality of ridge portions 53 has a plurality of concave portions 57. The concave portions 57 have an elongated shape in which the length in the first direction x is longer than the length in the second direction y, and a plurality of them are arranged at intervals in the first direction x. Each of the plurality of concave portions 57 is recessed in the thickness direction z and has a base portion 59 at its bottom. The base portion 59 is made of continuous fibers. The amount of continuous fibers in the base portion 59 is less than that in the portion excluding the base portions 59 of the plurality of ridge portions 53. The thickness Tb of the base portion 59 is thicker than the thickness Tc of each of the plurality of groove portions 55. That is, the thickness Tc of each of the plurality of groove portions 55 is thinner than the thickness Tb of the base portion 59.

[0107] The plurality of ridge portions 53 has a bundle portion 61 on one side in the second direction y of at least a part of the concave portion 57. The bundle portion 61 has a plurality of continuous fibers in a state where the plurality of continuous fibers are oriented in the first direction x. The fiber-to-fiber distance between the continuous fibers in the bundle portion 61 is smaller than that when the continuous fibers are not oriented in a specific direction. That is, since the continuous fibers between the joint portions are oriented in the first direction x in the bundle portion 61, the fiber-to-fiber distance of the continuous fibers between the joint portions is smaller. Therefore, in the web 51, and thus in the spunbond nonwoven fabric 1, when a load in the thickness direction z is applied, the probability that the continuous fibers come into line contact with each other in the bundle portion 61 is high, so it is difficult to deform in the thickness direction z. The bundle portion 61 may be formed on both sides in the second direction y of the concave portion 57.

[0108] On the other hand, in the case of continuous fibers that are not oriented in a specific direction, since the continuous fibers between the joint portions are oriented in an unspecified direction, when a load in the thickness direction z is applied, the probability that the fibers come into point contact with each other is high, and the fibers in the non-contact range are likely to deform.

[0109] The thickness of the web 51 and the spunbond nonwoven fabric 1 in the unloaded state, the thickness of the plurality of groove portions 55, and the thickness of the base portion 59 are measured using a two-dimensional laser displacement meter. Examples of the two-dimensional laser displacement meter include the high-precision two-dimensional laser displacement meter LJ-G series (model: LJ-G030) manufactured by Keyence Corporation. Place the web 51 on a horizontal measuring table, and measure the displacement from the measuring table with a laser displacement meter for five different parts for each target location of the web 51, and take the average value of the five measured values as the thickness (mm) of each target location of the web 51.

[0110] Each of the plurality of ridge portions 53 may have a plurality of protruding portions 63 protruding toward each of the plurality of adjacent groove portions 55. Each of the plurality of protruding portions 63 protrudes in the second direction y and is arranged at intervals along the first direction x. Between the protruding portions 63 of each of the plurality of ridge portions 53, it is recessed in the second direction y. The plurality of protruding portions 63 are respectively provided on both sides of the plurality of ridge portions 53, and each protruding portion 63 may be provided at a position overlapping in the second direction y. When each protruding portion 63 is provided at a position overlapping in the second direction y, wide portions and narrow portions are respectively formed in the plurality of ridge portions 53 and the plurality of groove portions 55. Further, each protruding portion 63 may be provided at a position not overlapping in the second direction y. When each protruding portion 63 is provided at a position not overlapping in the second direction y, the plurality of ridge portions 53 and the plurality of groove portions 55 each have a substantially constant width.

[0111] The thickness Tc of each of the plurality of groove portions 55 is small in the amount of continuous fibers, and therefore thinner than the thickness Tb of the base portion 59, so that there is little overlap of the continuous fibers in the thickness direction z. That is, in the plurality of groove portions 55, the interval between the continuous fibers is larger. Therefore, the web 51 can be seen from one side to the other side in the thickness direction z through the interval between the continuous fibers in the plurality of groove portions 55, that is, the visibility is excellent.

[0112] The evaluation of visibility may be evaluated by the average transmittance obtained by the method shown below. First, prepare 5 samples of 100 mm × 100 mm. Place the samples on the black paper with the uneven surface facing up. Using a digital camera with 12 million pixels, photograph the entire sample from a position about 15 cm away from the sample so that the entire sample can be photographed. Import the obtained image into VHX-7000 manufactured by KEYENCE, set the automatic area measurement and extraction method as brightness (standard), and perform image processing with the following settings to calculate the transmittance. Then, the average value of the transmittances of the 5 samples is taken as the average transmittance of the non-woven fabric.

[0113] Measurement area 50 mm × 50 mm Filter setting Texture removal 10 Brightness non-uniformity removal 1 Extraction setting Brightness setting 0 - 148 Filling OFF Small particle removal OFF Shaping setting Filling Auto

[0114] As shown in FIG. 4, the wire mesh 101 for forming the web 51 includes a mesh body 105 composed of a plurality of wires 103 arranged in a net shape and having a conveying direction MD, a transverse direction CD, and a height direction H that are orthogonal to each other. Each of the plurality of wires 103 has a predetermined outer diameter. The mesh body 105 arranges the plurality of wires 103 as vertical and horizontal lines and intersects them one by one at regular intervals.

[0115] The wire mesh 101 has a plurality of ridges 107 that protrude from one surface of the mesh body 105 in the height direction H to the height direction H and extend along the conveying direction MD. The ridges 107 are arranged at a predetermined interval in the transverse direction CD. The ridges 107 block a part of the gaps formed between the wires 103 in the mesh body 105. Incidentally, when the plurality of ridges 107 extending along the conveying direction MD are collectively referred to, there may be a case where the ridges 107 are arranged in a stripe shape.

[0116] As shown in FIG. 5, the height H of the ridge 107 L may be 1.0 mm or more. The height H of the ridge 107 L is larger than the outer diameter of the wire 103, that is, it is preferable that the outer diameter of the wire 103 is smaller than the height H of the ridge 107. The width W of each of the plurality of ridges 107 L that is, the total length of the lengths in the transverse direction CD may be 50% or less of the length of the mesh body 105 in the transverse direction CD. The width W of each ridge 107 L is not limited to the case where it is constant and includes cases where it is partially different. The width W of each ridge 107 L is not limited to the case where it is constant and includes cases where it is partially different. The width W of each ridge 107 L may be an average value of measured values at a plurality of locations (for example, 5 locations) with a predetermined interval (for example, 100 mm) in the conveying direction MD. The width W of the ridge 107 LLet it be the length in the transverse direction CD of the portion in contact with the mesh body 105.

[0117] When using the wire mesh 101, the continuous fibers are deposited on the wire mesh 101 by being sucked from below the wire mesh 101. A part of the continuous fibers preferentially gathers between the ridges 107 where the ridges 107 of the mesh body 105 are not formed. Between the ridges 107, a part of the continuous fibers preferentially gathers, so that the continuous fibers become dense, and a plurality of ridge portions 53 of the web 51 are formed. Also, on the ridges 107, the continuous fibers become sparse, and a plurality of groove portions 55 of the web 51 are formed.

[0118] When the height of the ridge 107 is 1.0 mm or more, it becomes difficult for the continuous fibers to remain on the ridge 107, and the continuous fibers are accumulated between the ridges 107, so that it becomes easy to form a plurality of ridge portions 53 having a predetermined thickness. Since the continuous fibers accumulate between the ridges 107 along the ridges 107 so as to avoid the ridges 107, the fiber orientation along the first direction x of the plurality of ridge portions 53 is higher than the fiber orientation along the first direction x of the plurality of groove portions 55.

[0119] When the total length of the transverse direction CD lengths of the plurality of ridges 107 with respect to the length of the transverse direction CD of the mesh body 105 is 50% or less, a gas with a sufficient ventilation amount easily passes through the mesh body 105 excluding the ridges 107.

[0120] When the outer diameter of the wire 103 forming the wire mesh 101 is smaller than the height of the ridge 107, and the ridge 107 is higher than the wire 103 even at the portion where the wires 103 of the wire mesh 101 overlap, a plurality of groove portions 55 are easily formed. Also, since the portion where the wires 103 of the wire mesh 101 overlap is smaller than the ridge 107, it is difficult for the continuous fibers to be deposited on the portion where the wires 103 of the wire mesh 101 overlap, and by gathering at the mesh, it becomes easy to form a plurality of ridge portions 53 having recesses 57.

[0121] Further, when the continuous fibers accumulate between the ridges 107 on the wire mesh 101, the continuous fibers avoid the portions that bulge upward in the height direction among the overlapping portions of the wires 103, and gather in the meshes, so that the plurality of continuous fibers are oriented in the first direction x. By forming a joint portion in this state, a bundle portion in which the plurality of continuous fibers are oriented in the conveyance direction MD, that is, the first direction x, is formed.

[0122] The continuous fibers are preferably deposited on the wire mesh 101 at a fiber speed of 1000 m / min or more and 4500 m / min or less. When the fiber speed of the continuous fibers is 1000 m / min or more, the continuous fibers are likely to be deposited on the wire mesh 101, and a plurality of ridge portions 53 are likely to be formed. Further, when the fiber speed of the continuous fibers is 4500 m / min or less, the orientation of the continuous fibers on the wire mesh 101 can be suppressed from being disturbed, so that a plurality of ridge portions 53 are likely to be formed. Therefore, when the continuous fibers are within the above range, the web 51 having a plurality of ridge portions 53 and a plurality of groove portions 55 can be efficiently manufactured.

[0123] In addition, in the "web preparation step" in the method for manufacturing a nonwoven fabric according to the present disclosure, it is not limited to the specific embodiments disclosed in FIGS. 2 to 5, and known methods capable of forming a web including a high basis weight region and a low basis weight region are included.

[0124] [Nonwoven fabric forming step] FIG. 6 shows an example of an embossing roll among a pair of embossing rolls used in the nonwoven fabric forming step, specifically, the arrangement of the pressing portions at the tips of the plurality of protrusions 111 provided on the embossing roll. The embossing roll 109 shown in FIG. 6 includes a plurality of protrusions 111. The embossing roll 109 has a first protrusion direction D 1 corresponding to the first direction D 1 of the spunbond nonwoven fabric 1, and a second protrusion direction D 2 corresponding to the second direction D 2 of the spunbond nonwoven fabric 1. Note that the crossing angle between the conveyance direction MD and the first protrusion direction D 1 ’ is 15°, and the crossing angle between the first protrusion direction D 1 ’ and the second protrusion direction D 2 ’ is 90°.

[0125] The plurality of protrusions 111 are intermittently arranged in the first protrusion direction D 1 ’ at the first protrusion pitch P 1 ’, and are intermittently arranged in the second protrusion direction D 2 ’ at the second protrusion pitch P 2 ’. In other words, the plurality of protrusions 111 are arranged in a staggered pattern. Note that the squeezing portion of each of the plurality of protrusions 111 has a diameter of 0.8 mm, and the squeezing area of the squeezing portion is approximately 0.50 mm 2 . Also, each of the first protrusion pitch P 1 ’ and the second protrusion pitch P 2 ’ is 2.9 mm.

[0126] The embossing roll 109 provided with the plurality of protrusions 111 may be arranged on the wire mesh 101 side (i.e., the side where the plurality of ridges 53 and the plurality of groove portions 55 of the web 51 are formed), and an anvil roll (not shown) may be arranged on the side opposite to the wire mesh 101 (i.e., the side opposite to the side where the plurality of ridges 53 and the plurality of groove portions 55 of the web 51 are formed). Thereby, the formed spunbond nonwoven fabric 1 is likely to maintain its bulkiness, and the spunbond nonwoven fabric 1 is excellent in flexibility.

[0127] Further, an anvil roll (not shown) may be disposed on the wire mesh 101 side (i.e., the side where the plurality of ridges 53 and the plurality of grooves 55 of the web 51 are formed), and an embossing roll 109 having a plurality of protrusions 111 may be disposed on the side opposite to the wire mesh 101 (i.e., the side opposite to the side where the plurality of ridges 53 and the plurality of grooves 55 of the web 51 are formed). Thereby, heat is easily transferred from the plurality of protrusions 111 of the embossing roll 109 to the web 51, the amount of fusion of the heat-fusible fibers in the plurality of embossed portions 5 formed increases, and the spunbond nonwoven fabric 1 is excellent in strength. Note that the pair of embossing rolls shown in FIG. 6 is an example, and in the nonwoven fabric forming step, those known in the art can be used.

[0128] In the method for manufacturing a nonwoven fabric according to the present disclosure, the plurality of protrusions constituting the pair of embossing rolls may have the same or different squeezing areas for squeezing the web. When each of the plurality of protrusions has the same squeezing area, in order for the plurality of embossed portions to satisfy the requirements of formulas (1) to (6), it is preferable that the nonwoven fabric (web) has a high basis weight region and a low basis weight region. When each of the plurality of protrusions has a different squeezing area, the nonwoven fabric (web) may or may not have a high basis weight region and a low basis weight region. Even when the nonwoven fabric (web) does not have a high basis weight region and a low basis weight region, the plurality of embossed portions can satisfy the requirements of formulas (1) to (6).

Example

[0129] Hereinafter, the present disclosure will be described with examples, but the present disclosure is not limited to these examples. [Production Example 1] Using the wire mesh 101 (W shown in FIGS. 4 and 5 and provided with the stripes 107 arranged in a stripe shape L : 1.8 mm, pitch of the stripes 107: 4.0 mm), the web No. 1 was formed. The average basis weight of the web No. 1: BW was 13 g / m2 It was. For Web No. 1, using a pair of embossing rolls each having a plurality of protrusions 111 arranged in a staggered pattern as shown in FIG. 6, a plurality of embossed portions were formed to form Spunbond Nonwoven Fabric No. 1. The anvil roll was disposed on the wire mesh 101 side, and the embossing roll 109 having the plurality of protrusions 111 was disposed on the side opposite to the wire mesh 101. The average basis weight: BW of the Spunbond Nonwoven Fabric No. 1 was 13 g / m 2 It was.

[0130] [Production Example 2 and Production Example 3] Spunbond nonwoven fabrics No. 2 and No. 3 were formed in the same manner as in Production Example 1, except that the average basis weight: BW was changed as shown in Table 1. An image of the Spunbond Nonwoven Fabric No. 3 is shown in FIG. 8.

[0131] [Production Example 4] In the wire mesh 101, the pitch of the ridges 107 was changed from "4.0 mm" to '5.0 mm', and Spunbond Nonwoven Fabric No. 4 was formed according to Production Example 1, except that the average basis weight: BW was as shown in Table 1.

[0132] [Production Example 5] Spunbond nonwoven fabric No. 5 was formed in the same manner as in Production Example 1, except that the wire mesh 101 was changed to the wire mesh 101 shown in FIG. 7. Note that FIG. 7 is a view of the wire mesh 101 as seen from the height direction H, showing only the ridges 107 and omitting the wires. In the wire mesh 101 shown in FIG. 7, each of the ridges 107 has a dot shape (substantially circular) with a diameter of about 3.0 mm, and the ridges 107 are arranged in a staggered pattern such that the pitch of the ridges 107 in the transport direction MD is 8.0 mm and the pitch of the ridges 107 in the transverse direction CD is 6.0 mm.

[0133] [Production Example 6 and Production Example 7] The ridge 107 of the wire mesh 101 shown in Fig. 7 was set to a diameter of 5.0 mm, the pitch of the ridge 107 in the transport direction MD was set to 10.0 mm, the pitch of the ridge 107 in the transverse direction CD was set to 10.0 mm, and the average basis weight: BW was as shown in Table 1. Except for this, spunbond nonwovens No. 6 and No. 7 were formed in the same manner as in Production Example 5.

[0134] [Comparative Production Example 1] A spunbond nonwoven No. 8 was formed in the same manner as in Production Example 1, except that the wire mesh 101 was not provided with the ridge 107. [Comparative Production Examples 2 - 8] Commercially available spunbond nonwovens were purchased and designated as spunbond nonwovens No. 9 - No. 15.

[0135] [Examples 1 - 7 and Comparative Examples 1 - 8] Regarding the spunbond nonwovens No. 1 - No. 15, according to the method described in this specification, S AVE (mm 2 ), S MAX (mm 2 ), S MIN (mm 2 ), (S MAX - S MIN ) / S AVE , S MAX / S AVE , S MIN / S AVE ), and CV (%) were measured. These values are shown in Table 1. Also, regarding the spunbond nonwovens No. 1 - No. 15, the following fineness values were measured.

[0136] [Compression Characteristics per Unit Basis Weight] Table 1 shows the initial thickness: T 0 (mm), the thickness during compression: T m (mm) and "T 0 - T m " (mm), and the compression characteristics per unit basis weight: (T 0 - T m ) / BW [mm / (g / m 2 )], and Fig. 9 shows (SMAX -S MIN ) / S AVE and (T 0 -T m ) / BW. Note that in Fig. 9, "EX" means data related to spunbond nonwoven fabrics No. 1 to No. 7 (Examples), and "COM" means data related to spunbond nonwoven fabrics No. 8 to 15 (Comparative Examples).

[0137] [Bending rigidity per unit basis weight and per unit thickness] Table 1 shows the bending rigidity value: B (10 -4 mN×m 2 / m) measured according to the method described in this specification, and the bending rigidity per unit basis weight and per unit thickness: B / BW / T 0 [(10 -4 mN×m 2 / m) / (g / m 2 ) / mm]. Also, Fig. 10 shows the relationship between (S MAX -S MIN ) / S AVE and B / BW / T 0 . Note that in Fig. 10, "EX" means data related to spunbond nonwoven fabrics No. 1 to No. 7 (Examples), and "COM" means data related to spunbond nonwoven fabrics No. 8 to 15 (Comparative Examples).

[0138] [Breaking strength per unit basis weight] Table 1 shows the breaking strength: BR (N / 50mm) measured according to the method described in this specification, and the breaking strength per unit basis weight: BR / BW [(N / 50mm) / (g / m 2 )]. Fig. 11 shows the relationship between (S MAX -S MIN ) / S AVE and the breaking strength per unit basis weight: BR / BW [(N / 50mm) / (g / m 2 )]. Note that in Fig. 11, "EX" means data related to spunbond nonwoven fabrics No. 1 to No. 7 (Examples), and "COM" means data related to spunbond nonwoven fabrics No. 8 to 15 (Comparative Examples).

[0139]

Table 1

[0140] From the data of the compression characteristics per unit area weight (Table 1 and Figure 9), it can be seen that for Spunbond nonwovens No.1 to No.7, compared with Spunbond nonwovens No.8 to No.15, the compression characteristics per unit area weight are greater. That is, per unit area weight, the difference between the initial thickness (T 0 ) and the thickness during compression (T m ) of the nonwoven fabric is large. Therefore, when the user touches the nonwoven fabric, it can be seen that the nonwoven fabric is easily deformed in the thickness direction and has excellent flexibility.

[0141] B / BW / T 0 From the data of (Table 1 and Figure 10), it can be seen that for Spunbond nonwovens No.1 to No.7, compared with Spunbond nonwovens No.8 to No.15, the bending rigidity per unit area weight and per unit thickness is small, and when a force is applied, the nonwoven fabric is easily deformed, indicating excellent flexibility. From the data of the breaking strength per unit area weight (Table 1 and Figure 11), it can be seen that Spunbond nonwovens No.1 to No.7 have a breaking strength equal to or higher than that of Spunbond nonwovens No.8 to No.15.

Explanation of symbols

[0142] 1 Spunbond nonwoven fabric 3 Embossed area 5 Embossed part 7 First embossed part 9 Second embossed part 11 High area weight region 13 Low area weight region 51 Web 53 Ridge part 55 Groove part 57 Concave part 59 Base part 61 Bundle part 63 Protruding part PD Plane direction D 1 First direction D 2 Second direction P 1 First pitch P 2 Second pitch

Claims

1. A nonwoven fabric comprising an embossed area including a plurality of embossed portions regularly arranged in a planar direction, Let the maximum value of the individual areas of the plurality of embossed portions be S MAX and let the minimum value of the individual areas of the plurality of embossed portions be S MIN and let the average value of the individual areas of the plurality of embossed portions be S AVE When this is the case, the plurality of embossed portions in the embossed region satisfy the following formula (1): 0.94 ≤ (S MAX - S MIN ) / S AVE ≤ 2.50 Equation (1) satisfying characterized in that said nonwoven fabric.

2. The nonwoven fabric according to claim 1, wherein the nonwoven fabric is for an outer sheet or a liquid-permeable sheet of an absorbent article.

3. When the coefficient of variation of the individual areas of the plurality of embossed portions is CV, the plurality of embossed portions in the embossed area satisfy the following formula (2): 10 ≦ CV ≦ 70 Formula (2) The nonwoven fabric according to claim 1 or 2, satisfying

4. The plurality of embossed portions in the embossed area satisfy the following formula (3): 0.09 ≤ S MIN / S AVE Formula (3) satisfying The nonwoven fabric according to any one of claims 1 to 3.

5. Let the number of the plurality of embossed portions be N, and among the plurality of embossed portions, S AVE is the number of those having an area of 80% or more and 120% or less of 1 When set as N, the plurality of embossed portions in the embossed region satisfy the following formula (4): 0.26 ≤ N 1 / N ≤ 0.90 Equation (4) satisfying The nonwoven fabric according to any one of claims 1 to 4.

6. In the embossed area, the nonwoven fabric includes a high basis weight area having a basis weight higher than the average basis weight of the nonwoven fabric and a low basis weight area having a basis weight lower than the average basis weight,

7. Let the average value of the individual areas of the plurality of embossed portions in the low area per unit floor area be SL AVE When this is the case, the plurality of embossed portions in the embossed area satisfy the following formula (5): SL AVE <S AVE Formula (5) satisfying The nonwoven fabric according to claim 6.

8. Let the average value of the individual areas of the plurality of embossed portions in the high flatness amount region be SH AVE When this is the case, the plurality of embossed portions in the embossed region satisfy the following formula (6): S AVE <SH AVE Formula (6) satisfying The nonwoven fabric according to claim 6 or 7.

9. The nonwoven fabric according to any one of claims 6 to 8, wherein the nonwoven fabric is composed of continuous fibers.

10. In the embossed area, the high basis weight area and the low basis weight area are each composed of a ridge portion protruding in one direction in the thickness direction of the nonwoven fabric and a groove portion recessed in the one direction, The nonwoven fabric according to claim 9, wherein the ridge portion further has a plurality of recesses recessed in the one direction, and a base portion made of the continuous fibers is provided at the bottom of each of the plurality of recesses.

11. The planar direction includes a first direction and a second direction intersecting the first direction, The nonwoven fabric according to any one of claims 1 to 10, wherein the plurality of embossed portions are intermittently arranged at a first pitch in the first direction and intermittently arranged at a second pitch in the second direction.

12. The nonwoven fabric according to claim 11, wherein the intersection angle between the first direction and the second direction is 60 to 90°.

13. The nonwoven fabric according to claim 11 or 12, wherein the first pitch and the second pitch are the same.

14. A method for manufacturing the nonwoven fabric according to any one of claims 6 to 10, preparing a web including the high basis weight area and the low basis weight area Using a pair of embossing rolls including an embossing roll having a plurality of protrusions and an anvil roll, forming the plurality of embossed portions on the web to form the nonwoven fabric; including; each of the plurality of protrusions having the same squeezing area; The method is characterized by the above.

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