Nonwoven fabric for absorbent article

Abstract

To provide a nonwoven fabric for absorbent articles with high designability, achieving both softness and smoothness.SOLUTION: There is provided a nonwoven fabric for absorbent articles that comprise a first fiber layer and a second fiber layer laminated in the thickness direction, and include fiber fusion points at the intersections between fibers. The first fiber layer possesses an uneven structure comprising multiple protrusions and bottoms located between adjacent protrusions. Each of the multiple protrusions comprises a top portion and wall portions supporting the top portion, and the bottoms are provided with openings through the thickness direction. The second fiber layer is provided on the side where the bottom of the first fiber layer is located. The second fiber layer has raised portions on the side facing the first fiber layer, which penetrate into the area partitioned by the wall portions from the openings in the first fiber layer. The ratio (H2 / H1) of the thickness H2 of the raised portion to the thickness H1 of the first fiber layer is 0.6 or more and 1 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a nonwoven fabric for absorbent articles. [Background technology]

[0002] Nonwoven fabrics are used in a variety of applications, such as as constituent members of absorbent articles such as diapers, sanitary napkins, etc. For example, nonwoven fabrics used as topsheets of absorbent articles have a variety of structures. For example, Patent Document 1 describes a composite nonwoven fabric having a surface layer made of a water-repellent nonwoven fabric and a back layer made of a hydrophilic nonwoven fabric. The composite nonwoven fabric is made of a melt-blown nonwoven fabric. The water-repellent nonwoven fabric has perforations formed by spraying and depositing the fabric against a perforated plate, and a raised portion formed by the upper part of the hydrophilic nonwoven fabric protruding is arranged within a tubular portion formed by the perforations extending downward. The hydrophilic nonwoven fabric is formed with the raised portion by spraying and depositing fibers discharged from a belt-blowing die onto the back side of the water-repellent nonwoven fabric. In this case, the fibers discharged from the melt-blowing die are deposited along the shape of the water-repellent nonwoven fabric (surface layer), so the raised portion of the hydrophilic nonwoven fabric has a hollow structure. Patent Document 2 describes a topsheet consisting of a first sheet having liquid passages and a second sheet positioned on its underside. The second sheet is fused to the periphery of the lower opening of the liquid passages of the first sheet, and the fibers of the second sheet are loosened and extend along the walls of the liquid passages. This causes cavities to form in the second sheet at the liquid passages. The document describes that the cavities in the second sheet are formed by blowing meltblown fibers onto the first sheet using a meltblown extruder under the action of suction. Patent Document 3 describes a surface sheet having alternating ridges and grooves. The surface sheet is made of a nonwoven fabric and has a multilayer structure including a surface layer and a back layer. The surface layer is shown to have openings in the grooves. This surface sheet is formed by sequentially stacking a surface layer precursor and a back layer precursor on a concave-convex shaping belt, repeatedly pressing and spraying fluid on each layer, and finally performing a hot air treatment. The openings in the grooves of the surface layer are formed by using a convex-convex shaping belt with multiple cutouts at the tops of the peaks, and by separating the constituent fibers at the non-cutout portions. In this case, the back layer precursor is stacked with the convex-convex shaping belt in place, preventing the back layer precursor from protruding from the openings in the surface layer precursor toward the opposite surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-168728 [Patent Document 2] Japanese Patent Application Publication No. 6-166937 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-279098 Summary of the Invention [Problem to be solved by the invention]

[0004] Nonwoven fabrics shaped with unevenness, as shown in the aforementioned Patent Documents 1 to 3, can enhance the soft feel required for absorbent articles. However, if the surface of a nonwoven fabric is uneven, the depressions can impair smoothness when touched with the skin, such as with the fingers. The greater the difference in height between the unevenness, the more likely it is that the soft feel will improve but the smoothness will decrease. In other words, it is difficult to achieve both a soft feel and smoothness in an uneven nonwoven fabric. Furthermore, conventional nonwoven fabrics can be given visible patterns by the aforementioned unevenness, perforations, and embossing. The visibility of these patterns can, for example, remind consumers of the fabric's pleasant texture and high liquid absorbency (liquid permeability). However, depending on the degree of processing, the unevenness constituting the pattern may reduce smoothness as described above, the perforations may induce liquid return, or the embossed portions may film the fibers, reducing liquid absorption and softness. In other words, it is difficult to achieve both improved visibility (i.e., design) by making the pattern more distinct and smoothness, resistance to liquid return, and liquid absorbency and softness in nonwoven fabrics.

[0005] In view of the above, the present invention relates to providing a nonwoven fabric for absorbent articles that is both soft and smooth and has a high designability. [Means for solving the problem]

[0006] The present invention provides a nonwoven fabric for absorbent articles, which has a first fiber layer and a second fiber layer laminated in the thickness direction and includes fiber fusion-bonded portions at the intersections of the fibers, wherein the first fiber layer has an uneven structure with a plurality of protruding portions and a bottom portion provided between adjacent protruding portions, each of the plurality of protruding portions having an apex and a wall portion supporting the apex, and the bottom portion has an opening portion penetrating through the thickness direction, the second fiber layer is provided on the side of the first fiber layer on which the bottom portion is located, and the second fiber layer has, on the side facing the first fiber layer, raised portions that extend from the openings in the first fiber layer into areas defined by the wall portions, and a ratio (H2 / H1) of a thickness H1 of the first fiber layer to a thickness H2 of the first fiber layer is 0.6 or more and 1 or less. [Effects of the Invention]

[0007] The nonwoven fabric for absorbent articles of the present invention is both soft and smooth, and can also have improved design properties. [Brief explanation of the drawings]

[0008] [Figure 1]1 is a cross-sectional view schematically showing a preferred embodiment of a nonwoven fabric for absorbent articles according to the present invention. [Figure 2] (A) is a photograph in lieu of a drawing showing a cross section of the thickness direction of the nonwoven fabric for absorbent articles of this embodiment with a weight W that applies a load of 4.9 mN / cm2 placed on it, and (B) is a photograph in lieu of a drawing showing an enlarged view of the raised portion. [Figure 3] 1A and 1B are photographs showing an example of a pattern visible on one side of the nonwoven fabric for absorbent articles of the present embodiment. [Figure 4] 2 is a partially enlarged cross-sectional view schematically illustrating a raised portion and a wall portion of the nonwoven fabric for absorbent articles shown in FIG. 1. FIG. [Figure 5] 1 is a plan view schematically showing a specific example of a nonwoven fabric for absorbent articles according to the present embodiment, viewed from one side. [Figure 6] 6 is a cross-sectional view taken along the line R1-R1 of the nonwoven fabric for absorbent articles shown in FIG. 5. FIG. [Figure 7] 6 is a cross-sectional view taken along the line R2-R2 of the nonwoven fabric for absorbent articles shown in FIG. 5. FIG. [Figure 8] FIG. 1 is an explanatory diagram showing a schematic diagram of a preferred embodiment of the method for manufacturing a nonwoven fabric for absorbent articles according to the present invention, in which (A) shows a pressing step, (B) shows a step of orienting the fiber layer formed by pressing in a planar direction by blowing air, (C) shows a step of obtaining an unevenly perforated nonwoven fabric by a first hot air stream, (D) shows a step of laminating a second fiber web onto the unevenly perforated nonwoven fabric, and (E) shows a step of integrating the unevenly perforated nonwoven fabric and the second fiber web by a second hot air stream to form the second fiber web into a nonwoven fabric. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] FIG. 10 is a plan view showing a state in which the support body and the pusher member are combined together. [Figure 12] (A) and (B) are photographs showing the state of the fiber layer formed by the pressing process, and (C) and (D) are photographs showing the state of the fiber layer after the air blowing process. [Figure 13] 1A and 1B are scanned images obtained in measuring patterns by image analysis as an evaluation of design, where (A) shows the nonwoven fabric sample of Example 1, and (B) to (F) show the nonwoven fabric samples of Comparative Examples 1 to 3, 5, and 6. [Figure 14] The scanned image shown in Figure 13 is converted into a 16-color bitmap file, which is a black-and-white image, (A) shows the nonwoven fabric sample of Example 1, and (B) to (F) show the nonwoven fabric samples of Comparative Examples 1 to 3, 5, and 6. DETAILED DESCRIPTION OF THE INVENTION

[0009] A preferred embodiment of the nonwoven fabric for absorbent articles according to the present invention will be described below with reference to the drawings. In this specification, the nonwoven fabric for absorbent articles may be simply referred to as a nonwoven fabric. The nonwoven fabric 10 of this embodiment is a nonwoven fabric having fused fiber portions at the intersections of the fibers. For example, it may be an air-through nonwoven fabric in which the fused fiber portions are formed by an air-through method. Therefore, the nonwoven fabric 10 contains thermoplastic fibers as its constituent fibers. That is, the first fiber layer M1 and the second fiber layer M2 (described below) that constitute the nonwoven fabric 10 contain thermoplastic fibers as constituent fibers, and are nonwoven fabrics having the fused fiber portions. The first fiber layer M1 and the second fiber layer M2 are integrated by the fused fiber portions at the intersections of their respective fibers. When the nonwoven fabric 10 of this embodiment is an air-through nonwoven fabric, it is formed during the manufacturing process by air-throughing a fiber web in which unfused fibers are randomly entangled. Therefore, the fused fiber portions are formed as point bonds on the fiber surfaces at the intersections of the fibers. This means that the fused fiber area is extremely small compared to other types of nonwoven fabrics with fused fiber portions, such as meltblown nonwoven fabrics and spunbonded nonwoven fabrics, in which the fibers are bonded in a blended manner. In this regard, meltblown nonwoven fabrics and spunbonded nonwoven fabrics have traditionally been manufactured by ejecting molten resin from a nozzle and directly fiberizing and depositing the resin. Therefore, in meltblown nonwoven fabrics and spunbonded nonwoven fabrics, the constituent fibers are monofilament fibers, resulting in the aforementioned blended bonding. Furthermore, they tend to fuse along the fiber length, and do not achieve the point bonding state seen in air-through nonwoven fabrics. Therefore, when the nonwoven fabric 10 of this embodiment is an air-through nonwoven fabric, the nonwoven fabric 10 is bulky and has excellent deformability and recovery between the fibers due to the small fusion area caused by point contact, resulting in softness. From the viewpoint of making the point contact more clear, the constituent fibers are preferably composite fibers containing multiple resin components with different melting points, and more preferably core-sheath composite fibers.

[0010] As shown in FIG. 1 , the nonwoven fabric 10 of this embodiment has a first fiber layer M1 and a second fiber layer M2 laminated in the thickness direction Z. The nonwoven fabric 10 has a front side 10T and a back side 10B, with the first fiber layer M1 disposed on the front side 10T and the second fiber layer M2 disposed on the back side 10B. In the nonwoven fabric 10, for example, the front side 10T can be used as the surface. For example, when the nonwoven fabric 10 is used as a topsheet of an absorbent article, the front side 10T can be used as the skin-facing side. In this case, the first fiber layer M1 is also referred to as the upper layer, and the second fiber layer M2 is also referred to as the lower layer. Note that the front side 10T and the back side 10B refer to the front and back surfaces of the entire nonwoven fabric 10, as well as the front and back surfaces of the first fiber layer M1 and the second fiber layer M2, respectively. Furthermore, the thickness direction Z of the nonwoven fabric 10 also refers to the thickness direction Z of each of the first fiber layer M1 and the second fiber layer M2.

[0011] The first fiber layer M1 has a plurality of protrusions 1 protruding from one surface side 10T and bottom portions 2 provided between adjacent protrusions 1, 1. This gives the first fiber layer M1 an uneven structure in the thickness direction Z. The protrusions 1 are three-dimensional fiber layers standing in the thickness direction Z of the first fiber layer M1, and are located higher on the one surface side 10T than the bottom portions 2. Each of the plurality of protrusions 1 has an apex 1A and a wall portion 1B supporting the apex 1A.

[0012] The outer shape of one surface 10T of top portion 1A may be flat or curved. From the viewpoints of making it easier to recognize the depth of the unevenness, making the shadows around the apertures 3 (described below) in bottom portion 2 more distinct, and further enhancing the smoothness of nonwoven fabric 10, it is preferable that one surface 10T of top portion 1A be flat.

[0013] An end portion (also referred to as a base portion 1D) of the other surface side 10B of the wall portion 1B abuts against the second fiber layer M2. In the abutment region 4 between the wall portion 1B and the second fiber layer M2, the base portion 1D of the wall portion 1B is embedded in and integrated with (fixed to) the second fiber layer M2. From the viewpoints of increasing the bonding strength and maintaining the concave-convex shape of the first fiber layer M1, it is preferable that the base portion 1D of the wall portion 1B and the second fiber layer M2 are integrated by fused fiber portions at the intersections between the constituent fibers of the base portion 1D of the wall portion 1B and the constituent fibers of the second fiber layer M2.

[0014] (Method of dividing the fiber layer of the wall portion 1B) In the cross section of the nonwoven fabric 10 in the thickness direction Z, including the protrusions 1 and the bottoms 2 of the first fiber layer M1, the fiber layer of the wall portion 1B can be divided by the following method. That is, a nonwoven fabric having a cross section in the thickness direction including the top portion 1A, wall portion 1B, and second fiber layer M2 of the first fiber layer M1 is placed on the base of a microscope VHX6000 (product name, manufactured by Keyence Corporation) with the second fiber layer M2 (the other surface side 10B) facing downward. Next, a flat plate (e.g., a flat acrylic plate) is placed on the top portion 1A side (one surface side 10T) of the nonwoven fabric, and a pressure of 4.9 mN / cm is applied. 2 A load of 4.9mN / cm is applied.2 The load (a) is a load that simulates fluffing on the surface of the nonwoven fabric. In this state, the cross section in the thickness direction Z is observed under the microscope at 20x magnification, and the fiber layer in the first fiber layer M1 that is in contact with the flat plate is designated as the top portion 1A. The portion connecting the end of the top portion 1A and the surface of one side 10T of the second fiber layer M2 is designated as the wall portion 1B. In specifying the boundary between top 1A and wall 1B, the thickness of top 1A where wall 1B does not exist is defined as the thickness of the end of top 1A, and the portion excluding this thickness is defined as wall 1B.

[0015] The bottom portion 2 of the first fiber layer M1 is provided between adjacent convex portions 1, 1. More specifically, the bottom portion 2 refers to a region including the bottom of a recess (inter-convex portion recess 2U) recessed on the other surface side 10B between the convex portions 1, 1 and an end portion (base portion 1D) of the other surface side 10B of the wall portion 1B. This bottom portion 2 has openings 3 penetrating in the thickness direction Z. In the example shown in FIG. 1 , the entire bottom portion 2 except for the base portion 1D is the openings 3. In this case, the base portion 1D of the wall portion 1B corresponds to the bottom portion 2. The penetration of the openings 3 here means that, when focusing on the first fiber layer M1, the portions of the first fiber layer M1 where no constituent fibers are arranged penetrate both surfaces of the first fiber layer M1 in the thickness direction Z.

[0016] Unlike the fine pores formed between the fibers, the openings 3 are holes formed by processing the first fiber layer M1, and have a much larger pore area than the fine pores formed between the fibers. In FIG. 1, the entire bottom 2 except for the base 1D is shown as openings 3, but the size of the openings 3 can be selected appropriately depending on the width of the bottom 2, etc. For example, in the first fiber layer M1, instead of the entire bottom 2 except for the base 1D, a fiber layer extending from the base 1D may be present around the openings 3. The openings 3 should be at least 10.0 mm 2 It is preferable that the openings 3 have a hole area of ​​at least 10 mm. The size of the openings 3 can be measured using the microscope described above. Specifically, the area of ​​the openings 3 is measured at 10 locations using the microscope, and the average value of these measurements is taken as the hole area of ​​each opening 3.

[0017] The planar shape of the openings 3 can be various from the viewpoint of enhancing liquid permeability, and examples thereof include a circle, an ellipse, and a rectangle.

[0018] The second fiber layer M2 is disposed on the side of the first fiber layer M1 where the bottom portion 2 is located. The second fiber layer M2 has, on the surface facing the first fiber layer M1, raised portions 5 extending from the openings 3 of the first fiber layer M1 into the region defined by the wall portions 1B. Specifically, the raised portions 5 are located on one side 10T of the base portions 1D of the wall portions 1B in the contact region 4, in the space between the convex portions 1, 1 of the first fiber layer M1, sandwiched between the wall portions 1B. Meanwhile, the second fiber layer M2 in the contact region 4 adjacent to the raised portions 5 forms a recessed portion 6 due to the recession of the base portions 1D of the wall portions 1B. The raised portions 5 have a skirt portion 7 extending toward the base portions 1D of the wall portions 1B. The skirt portion 7 is located at the base of the rise of the raised portions 5 and is connected to the recessed portion 6 in the contact region 4. In other words, the skirt portion 7 is located at the base of the rise from the base portions 1D of the wall portions 1B. As a result, the protrusions 5 extend from the depressions 6 to the base 7 into the region defined by the wall 1B of the first fiber layer M1, and then rise to the height of the protrusion apex 5A. The protrusion apex 5A is located at the top of the protrusion 5 in the thickness direction.

[0019] The height of the raised portion 5 is determined in relation to the projection 1 as follows. That is, the ratio (H2 / H1) of the thickness H2 of the protrusions 5 to the thickness H1 of the first fiber layer M1 is set to 0.6 or more and 1 or less. As a result, when a finger comes into contact with one surface 10T of the nonwoven fabric 10, the protrusions 1 and the protrusions 5 each act to support the surface of the finger. As a result, the surface of one surface 10T of the nonwoven fabric 10 becomes a smooth structure at the time of said contact. For example, when the ratio (H2 / H1) is 0.6, for example, when a parent gently presses and strokes the surface of a sheet with their fingertip to check its smoothness before putting a diaper on a baby, the surface of the sheet will be smooth. 2 (50gf / cm 2 )), the thickness of the convex portions 1 and the raised portions 5 become uniform, and one surface side 10T of the nonwoven fabric 10 feels smooth as described above. The blowing of air W1 onto the porous fibrous web 101 in the manufacturing method described below contributes to making the raised portions 5 bulky while also achieving the thickness defined by the ratio (H2 / H1). That is, the blowing of air W1 straightens out any disorder in the fibrous web in the portions that will become the wall portions 1B, eliminating the intrusion of fibers into the openings 3 between the wall portions 1B, and making the pore diameters clearer and larger. This allows the raised portions 5 to smoothly enter the spaces partitioned by the wall portions 1B from the openings 3, thereby achieving the thickness ratio (H2 / H1).

[0020] The thickness H1 of the first fiber layer M1 refers to the height in the thickness direction Z from the surface of one face side 10T of the apex 1A to the boundary between the recessed portion 6 (second fiber layer M2) of the base portion 1D (first fiber layer M1) in the contact region 4. The thickness H2 of the raised portion 5 refers to the height in the thickness direction Z from the surface of one face side 10T of the raised apex 5A to the boundary between the recessed portion 6 (second fiber layer M2) of the base portion 1D (first fiber layer M1) in the contact region 4. This is 4.9 mN / cm 2 2(A) and 2(B), the nonwoven fabric 10 is placed on a flat table with the other surface 10B facing downward, and a load of 4.9 mN / cm is applied to one surface 10T. 2 A weight W is placed on the first fiber layer M1, which acts as a load. In this state, the thickness H1 of the first fiber layer M1 and the thickness H2 of the raised portions 5 are measured. In measuring the thicknesses, the fiber layer of the raised portions 1 and the fiber layer of the raised portions 5 can be distinguished as follows. That is, a nonwoven fabric having a cross section in the thickness direction including the convex portions of the first fiber layer M1, the wall portion 1B, and the second fiber layer M2 is placed on the base of a microscope VHX6000 (product name, manufactured by Keyence Corporation) with the second fiber layer M2 (the other surface side 10B) facing downward. Next, a flat plate (e.g., a flat acrylic plate) is placed on the convex portion 1 side of the nonwoven fabric, and a pressure of 4.9 mN / cm is applied. 2 In this state, the cross section in the thickness direction Z is observed with the microscope, and the fiber layer in the first fiber layer M1 in the portion in contact with the flat plate is designated as the protrusion 1. The protrusions 5 are located closer to the first fiber layer M1 than the base 1D of the wall 1B, and the fiber layer in the recess space surrounded by the wall 1B between the protrusions 1 is referred to as the second fiber layer M2. If it is difficult to distinguish between the first fiber layer M1 and the second fiber layer M2, the second fiber layer M2 can also be identified by peeling the first fiber layer M1 from the nonwoven fabric 10. This method is particularly preferred when the ratio (H2 / H1) of the thickness H1 of the protrusions 1 to the thickness H2 of the protrusions 5 is close to 1.0. In FIGS. 2(A) and 2(B), the surface of one side 10T of the second fiber layer M2 is indicated by a dashed line in order to make the shape of the second fiber layer M2 easier to see on the image.

[0021] The raised portions 5 have a solid structure filled with the constituent fibers of the second fiber layer M2. In this solid structure, the raised portions 5 have the aforementioned fused fiber portions, and the fused fiber portions are preferably in a state of point bonding on the fiber surfaces at the intersections of the fibers. This is because, as shown in the manufacturing method described below, the raised portions 5 are formed by subjecting the second fiber web 103 before fusion toward the first fiber layer M1 through hot air treatment. The raised portions 5 are formed by gently pressing the highly mobile fibers before fusion with hot air, thereby bonding the fibers to each other on their fiber surfaces. Therefore, the fiber network structure of the raised portions 5 is significantly different from that of a meltblown nonwoven fabric having perforations formed by ejecting molten resin, as shown in Patent Document 1, for example, which is formed by spraying and depositing the molten resin on the perforations of the meltblown nonwoven fabric. That is, the raised portions 5 in the nonwoven fabric 10 of this embodiment are point-bonded by gently pressing in with hot air, resulting in an extremely small fused area at the fused fiber portions and a bulky fiber network structure. The fiber network structure of the raised portions 5 has excellent deformability and recovery between fibers due to the small fused area and bulkiness, and this gives the raised portions 5 their softness. In contrast, those that are raised by spraying and depositing melt-blown fibers, as in Patent Documents 1 and 2, result in a thin melt-blown nonwoven structure in which the fibers are bonded together so as to be assimilated. Therefore, the fused area is small like the raised portions 5, and a bulky fiber network structure is not obtained.

[0022] As a result, nonwoven fabric 10 also has softness on one surface side 10T due to protrusions 5. In other words, nonwoven fabric 10 achieves both softness and smoothness, and further improves this.

[0023] In addition, the protrusions 1 and the raised portions 5 exhibit somewhat independent deformation behavior due to the different forming steps and methods in the manufacturing method described below. Therefore, while the nonwoven fabric 10 has the aforementioned smoothness with a nearly flat surface shape, the protrusions 1 and the raised portions 5 exhibit different deformability to external forces (external forces from multiple directions, including pressure), as well as flexibility (soft feel) due to the uneven shape, allowing both to exhibit unique cushioning properties. For example, when external pressure is applied to one side 10T of nonwoven fabric 10, such as rubbing the skin surface with body pressure, convex portions 1 and raised portions 5 deform independently to some extent while also working together. This allows convex portions 1 and raised portions 5 to adhere to and conform to the skin, respectively, providing softness and smoothness with unique cushioning properties. Furthermore, when the nonwoven fabric 10 is pressed in the thickness direction Z, the protrusions 1 and the raised portions 5 can exhibit different deformabilities. In the protrusions 1, the tops 1A supported by the walls 1B give a sense of thickness to the skin when the skin is touched by a finger or the like. 2 The slight sinking of the protrusions 1 under the load (load Z) allows the skin to come into contact with the raised portions 5, providing a soft and smooth feel supported by the fiber layers of the protrusions 1 and 5. Further pressure causes the protrusions 1 to sink and bend at the wall portions 1B, and the protrusions 5, having the bulky fiber network structure described above, deform more softly and fluffy than the protrusions 1. At this time, the support of the wall portions 1B makes the protrusions 1 less likely to wear out while deforming, and they exhibit high elasticity and recovery. As the thickness of the protrusions 1 recovers, the spaces between the protrusions 1, 1 also recover, and the protrusions 5 also recover easily. As a result, under pressure in the thickness direction Z, the nonwoven fabric 10 has an uneven shape that gives the skin a comfortable thickness and smoothness, while also exhibiting a distinctive plump, soft cushioning property due to the unique two-stage deformation and recovery properties of the protrusions 1 and 5.

[0024] The unique cushioning properties described above are due to the different forming steps and methods for the convex portions 1 and the raised portions 5, as described above. That is, the protrusions 1 are formed by directly pressing the first fiber web 100 before fusion bonding using mechanical pressure from the pressing unit 131. Therefore, the unevenness can be created while the web remains soft, without hardening the fibers as in embossing. During this process, the wall portions 1B support the crests 1A due to the pressing shaping, so the protrusions 1 feel thick on the skin of the fingers and exhibit the aforementioned sinking and elasticity. Meanwhile, the raised portions 5 are formed by raising the second fiber web 103 before fusion bonding using the blowing pressure of hot air. The protrusions 1 are first shaped to increase the unevenness, and then the second hot air W3 is blown onto the raised portions 5. Therefore, in the space partitioned by the wall portions 1B, the fibers travel a long distance in the thickness direction, dispersing and increasing the interfiber distance as they penetrate. As a result, the raised portions 5 form a fluffy, high, and bulky fiber network structure. As a result, the nonwoven fabric 10 exhibits the above-described unique behavior on the one surface side 10T.

[0025] To further enhance the above-mentioned effect, the ratio (H2 / H1) of the thickness H2 of the protrusions 5 to the thickness H1 of the first fiber layer M1 is preferably 0.6 or more, more preferably 0.65 or more, and even more preferably 0.70 or more. The ratio (H2 / H1) of the thickness H2 of the protrusion 5 to the thickness H1 of the first fiber layer M1 is preferably 1 or less, more preferably 0.95 or less, and even more preferably 0.9 or less, from the viewpoint of more clearly expressing the distinctive plump and soft cushioning properties resulting from the unique two-stage deformation and recovery properties of the protrusion 1 and the protrusion 5.

[0026] Furthermore, in the nonwoven fabric 10, the raised portions 5 have a bulky fiber network structure, and therefore have higher light transmittance than the convex portions 1. This makes it easier to visually recognize the areas of the first fiber layer M1 where the open pores 3 exist. Specifically, when nonwoven fabric 10 is viewed from one surface side 10T in plan view, even though the entire surface is covered with fibers, it appears as if a pattern is formed by convex portions 1 and raised portions 5 in the areas of apertures 3. For example, as shown in Figures 3(A) and (B), a pattern is visible in the dark white areas of convex portions 1, with the light white of raised portions 5 dotted with low-brightness colors that allow the black of the underlying fabric to show through. Furthermore, the valley formed by the wall 1B constituting the convex portion 1 and the base 7 of the raised portion 5 can be recognized as a shadow. This valley shadow is further emphasized by the formation of a dividing line where the fibers change discontinuously between the wall 1B and the raised portion 5 due to differences in the forming process and method in the manufacturing method described below (Fig. 4). In this way, the nonwoven fabric 10 visually evokes not only a two-dimensional but also a three-dimensional aesthetic, making it highly aesthetically pleasing. As a result, when the highly designable nonwoven fabric 10 is used as the top sheet of an absorbent article, even if the fibers of the convex portion 1 and the raised portion 5 are the same white color, a user who picks up the absorbent article will be able to recognize the presence of irregularities and holes in the top sheet, and will be reminded of the high quality of the article, such as its pleasant feel and high absorbency.

[0027] Additionally, in the nonwoven fabric 10, the protrusions 5 of the second fiber layer M2 that penetrate into the first fiber layer M1 allow liquid to migrate more smoothly from the first fiber layer M1 to the second fiber layer M2 through the openings 3. This further improves the liquid permeability of the topsheet in an absorbent article that incorporates the nonwoven fabric 10 as a topsheet, further suppressing liquid return and making it less likely for liquid to remain on the skin.

[0028] In the nonwoven fabric 10, the fibers in the wall portion 1B are preferably oriented in a planar direction. Planar orientation here refers to the direction along a plane (e.g., a flat base) that contacts the surface of the other side 10B of the nonwoven fabric 10. This allows the pressure load in the thickness direction Z of the nonwoven fabric 10 to be dispersed in the planar direction, further enhancing the soft, resilient cushioning properties of the fiber layer. In addition, the fiber orientation in the wall portion 1B suppresses the rise of liquid from the second fiber layer M2 side, improving the prevention of liquid backflow. In other words, it improves the quality of liquid absorption in absorbent articles using the nonwoven fabric 10.

[0029] The fibers of the wall portion 1B are oriented in the planar direction, a feasible feasibility study. Specifically, the fibers of the wall portion 1B can be oriented in the planar direction by mechanically compressing the first fiber web 100 before fusion and then blowing air W1 onto it. In contrast, in conventional nonwoven fabrics, even if the fibers are fused together and then shaped to have irregularities in the thickness direction, the fiber orientation direction hardly changes. In other words, the fiber orientation direction in the thickness direction of the nonwoven fabric is not changed to the planar direction. Furthermore, in conventional nonwoven fabrics, when a fiber web before fusion is simply shaped to have irregularities, the fibers are aligned in the longitudinal direction of the compression. However, in the nonwoven fabric 10 of this embodiment, the fibers of the upright wall portion 1B are oriented in the planar direction, resulting in a fiber structure not found in conventional nonwoven fabrics.

[0030] Orienting the fibers of the wall portions 1B in the planar direction as described above facilitates the formation of thicker raised portions 5 in the manufacturing method described below. Specifically, the blowing of air W1 straightens out the disorder in the fiber web in the portion that will become the wall portions 1B, eliminating the possibility of fibers entering the openings 3 between the wall portions 1B, and increasing the pore size more clearly. Furthermore, as a result of blowing air W1, the fiber density of the wall portions 1B is increased compared to when the unevenness is formed. As a result, when the second hot air W3 is blown onto the second fiber web 103, the wall portions 1B of the first fiber layer M1 are less likely to collapse, the entrapment of the fibers in the wall portions 1B is suppressed, and the fibers of the second fiber web 103 are more likely to enter the spaces defined by the wall portions 1B through the openings 3. This allows the raised portions 5 in the nonwoven fabric 10 to be formed with greater thickness.

[0031] The "planar orientation" of the fibers in the wall portion 1B means that the longitudinal orientation rate of the fibers is less than 45%, as determined by the measurement method described below. By setting the longitudinal orientation rate of the fibers to less than 45%, the fibers are sufficiently aligned in the planar direction, and the aforementioned pressure resistance can be increased. From the viewpoint of further improving the aforementioned pressure resistance, the longitudinal orientation rate in the wall portion 1B is preferably 44% or less, more preferably 42% or less, and even more preferably 40% or less. Furthermore, from the viewpoint of pressure resistance, the longitudinal orientation rate in the wall portion 1B is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more.

[0032] (Method for measuring longitudinal orientation rate of fibers in wall portion 1B) As shown in FIG. 1, measurements are carried out on the wall portion 1B in the following procedure. That is, fibers are cut out from the fiber layer of the wall portion 1B from the middle of the length in the thickness direction Z of the wall portion 1B to the bottom portion 2, and observed under an SEM at 85 times magnification. Lines with sides of 1000 μm are marked in the vertical and horizontal directions on the observed image as reference lines. Each reference line is defined as the thickness direction and the planar direction of the nonwoven fabric 10. The total number of fibers passing through each reference line is counted. The fibers passing through the reference line in the planar direction of the nonwoven fabric 10 are defined as the "number of vertical fibers," and the fibers passing through the reference line in the thickness direction of the nonwoven fabric 10 are defined as the "number of horizontal fibers." The vertical orientation rate is calculated as (number of vertical fibers) / (number of horizontal fibers + number of vertical fibers) × 100 = vertical orientation rate (%). These are measured at nine points each, and the average is used as the value of the vertical orientation rate. The planar direction in the cross section of the nonwoven fabric 10 corresponds to the line L tangent to the surface of the other side 10B of the second fiber layer M2 shown in Figure 1. The thickness direction corresponds to the direction Z perpendicular to the line L.

[0033] In the nonwoven fabric 10, the fibers of the second fiber layer M2 are preferably oriented in the planar direction, which gives the raised portions 5 a bulky, solid structure, and the reduced fusion area between the fibers and the bulkiness result in a soft nonwoven fabric with excellent deformability and recovery properties. The fibers of the second fiber layer M2 being oriented in the planar direction means that the longitudinal orientation ratio measured by the following method is less than 45%. Preferably, the longitudinal orientation ratio of less than 45% is mainly exhibited on the surface of the second fiber layer M2 (the surface facing the first fiber layer M1).

[0034] (Method for measuring the longitudinal orientation rate of fibers in the second fiber layer M2) The second fiber layer M2 is measured according to the following procedure. A cross section of the fiber layer located at the protuberance 5 of the second fiber layer M2 is cut out in the thickness direction and observed under an SEM at 85x magnification. Reference lines, each 1000 μm long, are drawn in the vertical and horizontal directions on the observed image. Each reference line corresponds to the thickness and planar directions of the nonwoven fabric 10. The total number of fibers passing through each reference line is counted. The fibers passing through the reference line in the planar direction of the nonwoven fabric 10 are defined as the "number of vertical fibers," and the fibers passing through the reference line in the thickness direction of the nonwoven fabric 10 are defined as the "number of horizontal fibers." The longitudinal orientation rate is calculated as (number of vertical fibers) / (number of horizontal fibers + number of vertical fibers) × 100 = longitudinal orientation rate (%). Nine measurements are taken at each point, and the average is used as the longitudinal orientation rate value. If it is difficult to distinguish between the first fiber layer M1 and the second fiber layer M2, the second fiber layer M2 can be identified by peeling the first fiber layer M1 off the nonwoven fabric.

[0035] In addition, the base portion 7 of the second fiber layer M2 preferably has a fiber density different from that of the wall portion 1B of the first fiber layer M1. As described above, this difference in fiber density can be achieved by appropriately controlling the forming steps and methods for the protrusions 1 and the raised portions 5 in the manufacturing method described below. This results in a discontinuous change in fiber density between the bottom hem 7 and the wall 1B, making the shadows in the valleys more distinct and further enhancing the design of the nonwoven fabric 10. To make the discontinuous change more prominent, it is preferable that the fiber density change continuously in the raised portions 5. "Change continuously" here means that the fiber density is lowest at the peaks 5A of the raised portions 5 and increases continuously from the peaks 5A to the recesses 6. The "different fiber density" mentioned here means that the difference in fiber density between the skirt portion 7 and the wall portion 1B is 10 fibers / mm 2 The fiber density (R12) of the skirt portion 7 and the fiber density (R2) of the wall portion 1B are obtained by the measurement method described later.

[0036] Furthermore, it is preferable that the fiber density (R3) of the wall portion 1B is higher than the fiber density (R12) of the skirt portion 7. This makes the shadows of the valleys more distinct, and further enhances the design properties of the nonwoven fabric 10. From this viewpoint, the difference (R3-R12) between the fiber density (R3) of the wall portion 1B and the fiber density (R12) of the skirt portion 7 is 10 fibers / mm 2 More than 15 lines / mm is preferable. 2 More preferably, 20 lines / mm 2 The above is more preferable. The difference (R3-R12) is set to 80 threads / mm from the viewpoint of maintaining the strength of the nonwoven fabric. 2 Preferably less than 75 lines / mm 2 Less than 70 lines / mm is more preferable. 2More preferably, 50 fibers / mm or less 2 Even more preferably, 40 fibers / mm 2 Even more preferably, 30 fibers / mm 2 Even more preferred is the following:

[0037] From the viewpoint of enhancing the effect of highlighting the shadow between the base 1D of the wall portion 1B and the protrusion 5, it is preferable that the surface of the second fiber layer M2 facing the first fiber layer M1 is a continuous fiber layer extending in the planar direction. By forming the surface of the second fiber layer M2 facing the first fiber layer M1 as a continuous fiber layer extending in the planar direction, the above-mentioned shadow portion becomes more noticeable as a different portion in the continuous fiber layer.

[0038] In the nonwoven fabric 10, the area of ​​the openings 3 in the first fiber layer M1 is 10 mm 2 More than 60mm 2 or less. This area refers to the area of ​​each individual aperture 3. This area is larger (approximately twice as large) than apertures formed in conventional nonwoven fabrics for absorbent articles. The arrangement of apertures 3 with such a large area is possible because the aforementioned raised portions 5 are formed thicker in relation to the thickness of the convex portions 1, and the fibers of the wall portions 1B are oriented in the planar direction, thereby suppressing liquid return. This makes the design of the aforementioned pattern more clearly visible. By making the area of ​​the openings 3 equal to or greater than the lower limit, the raised portions 5 formed by the manufacturing method described below can be made larger, bulkier, and thicker, making it easier to more effectively express the aforementioned unique cushioning properties of the nonwoven fabric 10, and further improving both softness and smoothness. From this viewpoint, the area of ​​the opening 3 is 10 mm 2 More than 12mm is preferable. 2 More than 15mm is preferable. 2 The above is more preferable. By setting the area of ​​the openings 3 to the upper limit value or less, the softness due to the uneven structure can be further enhanced. From this viewpoint, the area of ​​the opening 3 is 60 mm 2Less than 40mm is preferable 2 Less than 30mm is preferable 2 The following is even more preferred:

[0039] (Method of measuring the area of ​​the opening 3) A nonwoven fabric including the convex portions 1, wall portions 1B, and second fiber layer M2 of the first fiber layer M1 is cut into a 10 cm x 10 cm square, and the first fiber layer M1 is peeled off to obtain the first fiber layer M1. The first fiber layer M1 is then placed on the base of a microscope VHX6000 (product name, manufactured by Keyence Corporation) with the surface of the first fiber layer M1 that abuts against the second fiber layer M2 (the other surface 10B) facing downward. In this state, the fabric is observed from a planar direction using the microscope, and the recessed space surrounded by the wall portions 1B (the space of the recessed portion 2U between the convex portions) is defined and its area is measured. The areas of 10 openings are measured from one piece of nonwoven fabric, and the average value is taken as the area of ​​the opening 3.

[0040] In the nonwoven fabric 10, the fiber density (R1) of the raised peaks 5A in the second fiber layer M2 is preferably lower than the fiber density (R2) of the peaks 1A in the first fiber layer M1. As described above, this difference in fiber density can be achieved by appropriately controlling the forming steps and methods for the convex portions 1 and the raised portions 5 in the manufacturing method described below. This allows the aforementioned unique cushioning properties of the nonwoven fabric 10 to be more pronounced. From this viewpoint, the difference (R2-R1) between the fiber density (R1) of the raised apex 5A and the fiber density (R2) of the apex 1A is preferably 25 or more, more preferably 35 or more, and even more preferably 40 or more. From the viewpoint of more effectively suppressing deterioration in smoothness due to fluffing of the raised peaks 5A, the difference (R2-R1) is preferably 75 or less, more preferably 65 or less, and even more preferably 60 or less.

[0041] Similarly, the fiber density (R1) of the raised peaks 5A in the second fiber layer M2 is preferably lower than the fiber density (R3) of the wall portions 1B in the first fiber layer M1. As described above, this difference in fiber density can be achieved by appropriately controlling the different forming steps and methods for the convex portions 1 and the raised portions 5 in the manufacturing method described below. Furthermore, in the manufacturing method described below, if the density of the wall portions 1B is increased by controlling the blowing of air W1, the raised portions 5 formed by the subsequent hot air treatment will be bulkier and have a lower fiber density. This allows the aforementioned unique cushioning properties of the nonwoven fabric 10 to be more pronounced. From this viewpoint, the difference (R3-R1) between the fiber density (R1) of the raised peaks 5A and the fiber density (R3) of the wall portions 1B is preferably 40 or more, more preferably 50 or more, and even more preferably 55 or more. From the viewpoint of more effectively suppressing deterioration in smoothness due to fluffing of the raised peaks 5A, the difference (R3-R1) is preferably 90 or less, more preferably 80 or less, and even more preferably 75 or less.

[0042] From the viewpoint of further improving the cushioning feeling, the fiber density (R1) of the raised peaks 5A is preferably 65 or less, more preferably 55 or less, and even more preferably 50 or less. From the viewpoint of more effectively suppressing deterioration of smoothness due to fluffing of the raised peaks 5A, the fiber density (R1) is preferably 15 or more, more preferably 25 or more, and even more preferably 30 or more. The fiber density (R2) of the top portion 1A is preferably 70 or more, more preferably 75 or more, and even more preferably 80 or more, from the viewpoint of more effectively suppressing deterioration of smoothness due to fluffing at the top portion. The fiber density (R3) of the wall portion 1B is preferably 85 or more, more preferably 90 or more, and even more preferably 95 or more, from the viewpoint of further enhancing the cushioning feeling.

[0043] Furthermore, in the second fiber layer M2, the fiber density (R1) of the ridge peaks 5A is preferably lower than the fiber density (R12) of the bottoms 7 and the fiber density (R13) of the depressions 6 (see, for example, FIG. 4). This difference in fiber density can be achieved by appropriately controlling the difference in the influence of the hot air blown through during the hot air treatment in the manufacturing method described below. This allows the ridge peaks 5A of the bulky protrusions 5 to deform more easily, and the bottoms 7 and depressions 6 support the deformation, more effectively preventing the protrusions 5 from losing their shape or becoming worn down. In other words, the soft cushioning properties of the protrusions 5 themselves are further enhanced. From this viewpoint, the difference (R12-R1) between the fiber density (R1) of the ridge top 5A and the fiber density (R12) of the bottom 7 is preferably 10 or more, more preferably 12 or more, and even more preferably 15 or more. From the viewpoint of more effectively suppressing deterioration in smoothness due to fluffing of the raised portions, the difference (R12-R1) is preferably 30 or less, more preferably 28 or less, and even more preferably 25 or less. From the above viewpoint, the difference (R13-R1) between the fiber density (R1) of the ridge apex 5A and the fiber density (R13) of the depression 6 is preferably 20 or more, more preferably 22 or more, and even more preferably 25 or more. In order to more effectively prevent deterioration in smoothness due to fluffing of the raised portions, the difference (R13-R1) is preferably 40 or less, more preferably 38 or less, and even more preferably 25 or less.

[0044] The fiber density (R1) of the raised apex 5A is preferably 90 or less, more preferably 85 or less, and even more preferably 80 or less, from the viewpoint of more effectively suppressing liquid residue. The fiber density (R12) of the bottom hem 7 is preferably 35 or more, more preferably 40 or more, and even more preferably 50 or more, from the viewpoint of more effectively preventing the garment from losing its shape or becoming worn down. The fiber density (R13) of the recessed portion 6 is preferably 45 or more, more preferably 50 or more, and even more preferably 60 or more, from the viewpoint of more effectively preventing deformation and settling.

[0045] The fiber density (R2) of the top 1A and the fiber density (R3) of the wall 1B, as well as the fiber density (R1) of the raised top 5A, the fiber density (R12) of the bottom 7, and the fiber density (R13) of the recess 6, are measured by the following method.

[0046] (Method of measuring fiber density (R2) of top portion 1A, fiber density (R3) of wall portion 1B, fiber density (R1) of raised top portion 5A, fiber density (R12) of bottom portion 7, and fiber density (R13) of recessed portion 6) The fiber density can be measured by the following method by observing a cross section of the nonwoven fabric 10. The nonwoven fabric 10 is cut in the thickness direction Z so as to pass through the area to be measured. On the cut cross section, the measurement points for each part are specified as follows: The top portion 1A is observed at a cross section located at the center in the planar direction relative to the thickness direction Z. That is, the top cross section is observed at the center of the top located between one wall portion and the other wall portion. The wall portion 1B is observed at a cross section located at the midpoint of the height from the middle portion in the thickness direction Z to the bottom portion 2. For the ridge apex 5A, a position within 0.5 mm from the maximum height of one surface side 10T in the cross section of the thickness direction Z of the ridge 5 and a middle position between the depressions 6 on both ends of the ridge 5 are observed. The skirt 7 is observed at a midpoint between the top 5A of the raised portion and the depression 6 in the planar direction, and at a position within a range of 0.5 mm from the maximum height of the one surface side 10T at the midpoint. The depression 6 is observed at a position in the protrusion 5 that corresponds to the wall 1B and that is within a range of 0.5 mm from the maximum height of the one surface side 10T of that position. The cut surface of the fiber layer is observed at 130x magnification using a scanning electron microscope (JCM-6000Plus (trade name) manufactured by JEOL Ltd.), and square reference lines measuring 600 μm on a side are drawn vertically and horizontally on the image observed at the aforementioned observation position. The number of cut fiber cross sections within a certain area of ​​the cut surface defined by these reference lines is then counted. 2 This is converted into the number of fiber cross sections per unit area, and the fiber density (fibers / mm 2 The results of the nine measurements are averaged to determine the fiber density of the sample. If it is difficult to observe the cross section of the fiber at the above magnification, enlarge the observation to a magnification that allows 20 to 30 cross sections of the fiber to be observed, and count the number of cross sections of the cut fiber within a certain area of ​​the cut surface. 2This is converted into the number of fiber cross sections per unit area, and the fiber density (fibers / mm 2 In this case, the fiber density of the sample is calculated by averaging the results of the measurements at nine locations.

[0047] In the nonwoven fabric 10, when viewed from above from the first fiber layer M1, the basis weight (Q1) of the region where the first fiber layer M1 is present is 10 g / m 2 higher than the basis weight (Q2) of the raised portions 5 of the second fiber layer M2. 2 It is preferable that the light transmittance is higher than that of the peaks 1A. This makes the light transmittance at the protrusions 5 more pronounced than at the peaks 1A, and the above-mentioned pattern is more clearly visible. This further enhances the above-mentioned design properties of the nonwoven fabric 10. From this viewpoint, in the nonwoven fabric 10, when viewed from above from the first fiber layer M1, the difference (Q1-Q2) between the basis weight (Q1) of the region where the first fiber layer M1 is present and the basis weight (Q2) of the raised portion 5 is 10 g / m 2 More preferably, 15 g / m 2 The above is more preferable. From the viewpoint of more effectively maintaining the soft texture, the difference (Q1-Q2) is 50 g / m 2 Less than 40 g / m is more preferable. 2 The following is even more preferred: In addition, the basis weight of the area where the first fiber layer M1 is located, when viewed from above from the first fiber layer M1, means the sum of the basis weight of the first fiber layer M1 in the area excluding the open hole portion 3 of the first fiber layer M1 (non-open hole area) and the basis weight of the second fiber layer M2 overlapping it. The basis weight (Q2) of the protrusions 5 in the second fiber layer M2 in the top view from the first fiber layer M1 means the basis weight of the second fiber layer M2 in the region of the openings 3 of the first fiber layer M1.

[0048] (Method for measuring the aforementioned basis weight (Q1) and basis weight (Q2)) A nonwoven fabric 10 including the protrusions 1 and wall portions 1B of the first fiber layer M1 and the second fiber layer M2 is cut into a 10 cm x 10 cm square. The first fiber layer M1 is peeled off from the cut-out nonwoven fabric sample to obtain the first fiber layer M1. Next, the basis weight is measured at nine positions on the first fiber layer M1, and the average value is taken as the basis weight of the first fiber layer M1. Regarding the basis weight of the raised portions 5 in the second fiber layer M2, the first fiber layer is peeled off from the cut-out nonwoven fabric sample using the same method as above to obtain the second fiber layer M2. Next, the basis weight is measured at nine positions on the second fiber layer M2, and the average value is taken as the basis weight of the raised portions 5 in the second fiber layer M2. The aforementioned basis weight (Q1) is the sum of the basis weights of the first fiber layer and the second fiber layer, and the aforementioned basis weight (Q2) is the basis weight of the raised portions 5 in the second fiber layer.

[0049] The basis weight (Q1) of the region where the first fiber layer M1 is present is set to 20 g / m2 from the viewpoint of more suitably maintaining the cushioning feeling due to the unevenness. 2 More than 25g / m is preferable. 2 More preferably, 30 g / m 2 The above is more preferable. The basis weight (Q2) of the raised portion 5 is set to 10 g / m from the viewpoint of making the raised portion 5 a softer solid structure. 2 More than 15g / m is preferable. 2 More preferably, 20 g / m 2 The above is more preferable.

[0050] In addition, in the nonwoven fabric 10, the number of protrusions 5 is 4 per 25 cm 2 This makes it possible to further improve the visibility, that is, the design, by making the pattern clearer. From this viewpoint, the number of the protuberances 5 is 6 per 25 cm 2 More than 12 pieces / 25cm is preferable. 2 The above is more preferable. To maintain smoothness, the number of ridges 5 is 30 per 25cm. 2 Less than 25 pieces / 25cm is preferable. 2 The following is even more preferred:

[0051] The basis weight of the nonwoven fabric 10 is 20 g / m from the viewpoint of improving the texture of the nonwoven fabric and enhancing the shading of the valleys described above. 2 More than 30g / m is preferable. 2 More preferably, 40 g / m 2 The weight of the nonwoven fabric 10 is more preferably 120 g / m2 from the viewpoint of not interfering with the wearer's comfortable use. 2 Preferably less than 1000 g / m 2 Less than 85 g / m is more preferable. 2 The following is even more preferred:

[0052] Nonwoven fabric 10: 4.9mN / cm 2 (0.05gf / cm 2 The thickness under load is preferably 0.5 mm or more, more preferably 1.0 mm or more, and even more preferably 1.5 mm or more, in order to enhance the design of the handle. This thickness is 4.9 mN / cm 2 The strain can be measured using a laser displacement meter or the like under a load. 2 By ensuring that the thickness under load is within the above range, the liquid return prevention performance is improved, making it difficult for the wearer's skin to become wet. In addition, the nonwoven fabric 10 has a strength of 4.9 mN / cm 2 The thickness under load is preferably 15 mm or less, more preferably 10 mm or less, and even more preferably 7 mm or less, from the viewpoint of not interfering with the wearer's comfortable use.

[0053] Next, a more preferred embodiment of the uneven structure of the first fiber layer M1 in the nonwoven fabric 10 of this embodiment will be described.

[0054] The wall 1B of the first fiber layer M1 preferably has a shape extending perpendicular to the plane of the other surface 10B of the nonwoven fabric 10 (second fiber layer M2). The vertical wall surface of the wall 1B narrows the valley between the protrusion 5 at the base 1D of the wall 1B, making the shadow stronger. Furthermore, the shadow can be perceived as if it is floating from the vertical wall 1B. This further improves the visibility of the openings 3. In addition, the vertical wall 1B vertically connects the top 1A and the second fiber layer M2, which allows the soft fiber layer of the top 1A to remain supported by the elastic fiber layer of the wall 1B. The thickness of the fiber layer of the protrusion 1 can be felt through the top 1A, and the aforementioned unique cushioning properties are more clearly expressed.

[0055] The term "perpendicular" to the wall 1B means that the angle θ relative to the plane of the other side 10B of the nonwoven fabric 10 (second fiber layer M2) shown in FIG. 1 is not limited to a strict 90° angle, but also refers to an angle between 60° and 120°. This range allows the wall 1B to have a shape that extends at an angle that is substantially recognized as 90° in the thickness direction Z of the nonwoven fabric 10. The angle θ refers to the intersection angle between the plane of the other side 10B of the nonwoven fabric 10 and an extension of the wall 1B. Specifically, as shown in FIG. 1, in a cross section in the thickness direction including the protrusion 1, the angle θ refers to the interior angle between the center line M of the width of the fiber layer of the wall 1B and a straight line L tangent to the surface of the other side 10B of the nonwoven fabric 10 (second fiber layer M2). This angle θ can be determined by observing a micrograph of the cross section obtained with the microscope described above.

[0056] 1, the wall 1B extends linearly between the top 1A and the second fiber layer M2, and the entire wall 1B is erected perpendicular to the second fiber layer M2. However, this is not limited thereto, and the wall 1B may include a curved or wavy portion extending between the top 1A and the second fiber layer M2. In this case, the angle θ is determined by defining the center line M as the line connecting the boundary between the top 1A and the wall 1B and the boundary between the second fiber layer M2 and the wall 1B. Although it is preferable that all of the walls 1B extend perpendicular to the second fiber layer M2, some of the walls 1B may not extend perpendicular to the plane of the other surface 10B of the second fiber layer M2. In the latter case, the number of perpendicular walls 1B is preferably 60% or more of the walls 1B in all of the protrusions 1, from the viewpoints of further emphasizing the above-mentioned shading in the nonwoven fabric 10 and further enhancing the above-mentioned unique cushioning properties.

[0057] Additionally, it is preferable that the first fiber layer M1 has hollow regions 1C on the other side 10B of the protrusions 1 (inside the protrusions 1). The hollow regions 1C are spaces that are not substantially filled with the fibers of the nonwoven fabric 10. Specifically, the hollow regions 1C have a fiber density of 10 fibers / mm 2 or less, as determined by the method described below. 2 This means that the fiber density in the hollow regions 1C is less than 1 / 2. The lower the fiber density in the hollow regions 1C, the better. By having the hollow regions 1C on the other surface side 10B of the projections 1, the soft feel of the projections 1 is further improved, the cushioning properties mentioned above are further enhanced, and the feel of the nonwoven fabric 10 against the skin is further improved. Furthermore, when the nonwoven fabric 10 is used as a topsheet of an absorbent article, the presence of the hollow regions 1C cuts off the liquid return path from the absorbent body, further improving the prevention of liquid return. In addition, the hollow regions 1C also serve as a primary storage space in the event of excessive excretion, thereby reducing the amount of liquid remaining on the skin-contacting side of the topsheet. Furthermore, it is preferable that the inner-protrusions 8 of the second fiber layer M2 extend into the hollow regions 1C of the first fiber layer M1 in order to further improve the unique cushioning properties described above. That is, the presence of the inner-protrusions 8 inside the protrusions 1 enhances the shape retention of the peaks 1A and wall portions 1B of the first fiber layer M1. Therefore, when used as a topsheet for an absorbent article, sagging and deformation of the shape are further suppressed even when repeatedly compressed.

[0058] From the viewpoint of further improving the aforementioned unique cushioning properties, the ratio of the thickness of the inner protrusion 8 to the thickness of the first fiber layer M1 is preferably 0.6 or more, more preferably 0.65 or more, and even more preferably 0.7 or more, similar to the ratio (H2 / H1) of the thickness H2 of the protrusion 5 to the thickness H1 of the first fiber layer M1. The ratio of the thickness of the inner protrusions 8 to the thickness of the first fiber layer M1 is preferably 0.95 or less, more preferably 0.90 or less, and even more preferably 0.85 or less, which leaves a space in the hollow region 1C on the other surface side 10B of the protrusions 1 (inside the protrusions 1), thereby further maintaining the soft cushioning feel of the protrusions 1.

[0059] Next, a specific example (nonwoven fabric 20) of the nonwoven fabric 10 shown in Fig. 1 will be described with reference to Fig. 5 to Fig. 7. The nonwoven fabric 20 has the configuration described above for the nonwoven fabric 10. 5 to 7, in plan view from one surface side 20T, the nonwoven fabric 20 has a plurality of ribs 11 extending in one direction Y as the convex portions 1 of the first fiber layer M1 and arranged at a distance from each other in a direction X intersecting the one direction Y. The other surface side 20B of the ribs 11 is formed as a hollow region 11C. The one direction Y and the direction X intersecting the one direction Y can be set appropriately depending on the purpose on one surface side 20T of the nonwoven fabric 20. For example, the one direction Y and the direction X intersecting the one direction Y are preferably perpendicular to each other. When the nonwoven fabric 20 is used as a component such as a topsheet in an absorbent article, it is preferable that the one direction Y is the longitudinal direction of the absorbent article, and the direction X intersecting the one direction Y is the width direction of the absorbent article.

[0060] The ridges 11 have the same height in the extension direction. The "same" height means that the height measured using a microscope VHX900 (product name, manufactured by Keyence Corporation) is within a range of 0.8 to 1.2 times the average measurement value.

[0061] Each of the multiple ribs 11 includes a crest 11A and a wall 11B supporting the crest 11A. The crest 11A is a fiber layer that contacts the wearer's skin in an absorbent article, and the wall 11B is a fiber layer that connects the crest 11A and the second fiber layer M2 in the thickness direction. That is, when the nonwoven fabric 20 is applied to an absorbent article, the one surface side 20T is the skin-contacting surface, and the other surface side 20B is the non-skin-contacting surface. As described above, the fibers of the wall 11B are preferably oriented in a planar direction. Furthermore, the wall 11B preferably extends perpendicular to the second fiber layer M2 and perpendicularly connects the crest 11A and the bottom 12, where the perforations 3 are arranged. The longitudinal orientation ratio, which is an index of the orientation of the wall portions 11B in the rib portions 11 in the planar direction, and the "vertical" of the wall portions 11 refer to the interior angle between the center line M of the width of the fiber layer of the wall portions 11B and a straight line L tangent to the surface of the other side 20B of the nonwoven fabric 20 (second fiber layer M2) in a cross section perpendicular to the extension direction of the rib portions 11 (a thickness direction cross section at the position of line R1-R1 along direction X intersecting with one direction Y in FIG. 5), as shown in Fig. 6. This angle θ can be determined by observing a micrograph of the cross section along line R1-R1 obtained with the microscope described above.

[0062] The nonwoven fabric 20 has, as the protrusions 1 in the first fiber layer M1, the rib portions 11 described above, as well as saddle portions 15 connecting adjacent rib portions 11. Similar to the rib portions 11, the saddle portions 15 protrude from the second fiber layer M2 toward one surface 20T of the nonwoven fabric 20 and are three-dimensional fiber layers extending in the thickness direction of the nonwoven fabric 20. More specifically, the saddle portions 15 have a crest 15A on the one surface 20T and a wall portion 15B supporting the crest 15A. As described above, the fibers of the wall portion 15B are preferably oriented in the planar direction. Furthermore, the wall portion 15B preferably extends perpendicular to the second fiber layer M2. The term "perpendicular" here has the same meaning as the term "perpendicular" defined for the rib portion 11 described above. The longitudinal orientation rate, which is an indicator of the planar orientation of wall portion 15B in saddle portion 15, and the "vertical" of wall portion 15B can be measured in the same manner as the above-described measurement method for wall portion 11B for a cross section perpendicular to the extension direction of saddle portion 15 (thickness cross section at the position of line R2-R2 along one direction Y in FIG. 5), as shown in FIG.

[0063] The above structure makes it difficult for the ribs 11 connected by the saddle portions 15 to approach each other, preventing the ribs 11 from collapsing in one direction due to an external force such as pressure. That is, the saddle portions 15 support the ribs 11 from the sides, improving the shape retention of the ribs 11. This makes it easier for the ribs 11 to maintain their thickness under load, further enhancing the unique cushioning properties described above. Furthermore, when the nonwoven fabric 20 is incorporated into an absorbent article as a component closer to the skin than the absorbent body, for example, as a topsheet, the distance between the top portions 11A and the absorbent body side of the other surface side (non-skin-contacting surface side) 20B is easily maintained even under the pressure of the wearer's body when wearing the absorbent article, making it even more difficult for liquid to return to the one surface side (skin-contacting surface side) 20T. Furthermore, the presence of the saddle portion 15 acts to block excreted liquid between the ridge portions 11, 11, and the liquid flow prevention property on one surface side (skin contact surface) 20T of the nonwoven fabric 20 is improved.

[0064] In a plan view from one surface side 20T of the nonwoven fabric 20, the saddle portions 15 extend in a direction X that intersects with the direction Y in which the rib portions 11 extend. The direction X in which the saddle portions 15 extend can be any direction as long as it connects adjacent rib portions 11, and is preferably a direction perpendicular to the direction Y in which the rib portions 11 extend. For example, it is preferable that the direction Y in which the rib portions 11 extend is the longitudinal direction of the absorbent article, and the direction X in which the saddle portions 15 extend and that intersects with the direction Y is the width direction of the absorbent article. Hereinafter, the direction Y and the direction X that is perpendicular to the direction Y will also be referred to as the extension direction Y of the rib portions 11 and the extension direction X of the saddle portions 15. Furthermore, the planar shape of each saddle portion 15 as viewed from one surface side 20T is not limited to a rectangle as shown in Fig. 5, and may be various other shapes. For example, the planar shape of the saddle portion 15 as viewed from one surface side 20T may be such that the width increases toward the ridge portion 11.

[0065] As shown in Figures 6 and 7, the saddle portions 15 preferably have the same height in the thickness direction as the rib portions 11. The term "same height" is as defined above. This allows one surface 20T of the nonwoven fabric 20 to be substantially flush, excluding the bottom portion 12. This allows both the rib portions 11 and the saddle portions 15 to uniformly support the load even if the load is applied in various directions, and in combination with the raised portions 5, this further enhances the pressure resistance and unique cushioning properties. This effect is further enhanced by the fibers in the walls of the rib portions 11 and the saddle portions 15 being oriented in the planar direction.

[0066] In a plan view of one surface side 20T of the nonwoven fabric 20, the saddle portions 15 are arranged in a plurality of band regions 16 extending parallel to the ribs 11 between the ribs 11, 11. In each band region 16, a plurality of saddle portions 15 are arranged at intervals along the extension direction Y of the parallel ribs 11. The aforementioned openings 3 of the bottom portion 12 are located in the spaced apart saddle portions 15. That is, in each band region 16, the saddle portions 15 and the openings 3 are alternately arranged. As a result, the openings 3 are surrounded and defined by the walls 11B of the ribs 11 and the walls 15B of the saddle portions 15. More specifically, the region surrounded by the plurality of ribs 11 and the plurality of saddle portions 15, which are three-dimensional fiber layers standing in the thickness direction, forms a box-shaped or cylindrical recess, and the openings 3 are arranged in the bottom portion 12.

[0067] In the example shown in Figures 5 to 7, in a plan view from one surface 20T of the nonwoven fabric 20, the band regions 16, 16 adjacent to each other via a rib 11 are arranged in a staggered pattern such that the saddle portions 15 in one band region 16 correspond to the positions between the saddle portions 15 in the other band region 16. As a result, the openings 3 in the band regions 16 adjacent to each other via a rib 11 are not aligned in one direction Y, but are arranged offset in the one direction Y. When viewed from the direction X, the openings 3 adjacent in the direction X partially overlap and appear to always exist along the longitudinal direction. This staggered arrangement extends throughout the entire planar direction of the nonwoven fabric 20. As a result, when viewed from the direction X, there are no areas where openings 3 are not arranged, and therefore there are no areas where wall portions in which the constituent fibers of the rib regions 11 and saddle portions 15 are not arranged. This allows the load to be supported uniformly in the planar direction during compression, improving pressure resistance. At each of the staggered apertures 3, the protrusions 5 penetrate into the area defined by the wall portions 11B and 15B through the apertures 3, and the ratio (H2 / H1) of the thickness H2 of the protrusions 5 to the thickness H1 of the first fiber layer M1 is set to 0.6 or more and 1 or less. This allows the nonwoven fabric 20 to more stably exhibit the aforementioned softness and smoothness, as well as the aforementioned unique cushioning properties. Furthermore, the aforementioned pattern is also lattice-like, thereby further enhancing the design possibilities. In order to further enhance the above-mentioned effects in the nonwoven fabric 20, it is preferable that the ridge portions 11 and the saddle portions 15 have the above-mentioned inner protrusions 8.

[0068] In the nonwoven fabric 20, the arrangement of the ribs 11 and saddle portions 15 is not limited to the staggered arrangement described above, and various other arrangements are possible. For example, the openings 3 in adjacent band-like regions 16 separated by a rib 11 may be aligned in one direction Y. In this case, the ribs 11 and saddle portions 15 are arranged in a lattice pattern, and the openings 3 in the bottom portion 12 are dotted within the lattice to form a grid pattern.

[0069] Furthermore, from the viewpoint of further promoting drainage of liquid to the other surface 20B of the nonwoven fabric 20 when the nonwoven fabric 20 is used as a topsheet of an absorbent article, it is more preferable that the saddle portion 15 has a hollow region 15C as shown in FIG. 7. The definition and measurement method of this hollow region 15C are the same as those of the hollow region 11C in the rib portion 11. The hollow region 15C of the saddle portion 15 is preferably in communication with the hollow region 11C of the rib portion 11. This promotes the diffusion of excreted liquid on the other surface 20B of the nonwoven fabric 20, further suppressing liquid accumulation on the one surface 20T. As a result, the amount of liquid remaining in the nonwoven fabric 20 is more likely to be reduced, enabling a further reduction in the amount of liquid adhering to the skin.

[0070] Next, a preferred embodiment of a method for manufacturing the nonwoven fabric 20 will be described with reference to Figures 8 to 12. The manufacturing method described below can also be applied to a method for manufacturing the nonwoven fabric 10. The manufacturing method of this embodiment includes the following five steps, as shown in Figures 8(A) to 8(E) (hereinafter, each step may be referred to as step (I), step (II), step (III), step (IV), and step (V)). (I) A pressing process in which a first fiber web 100 is placed on a support 120 having an uneven shape with a plurality of protrusions 121 and recesses 125 between the protrusions 121, 121, and the first fiber web 100 is pressed along the recesses 125 by a pressing portion 131 of a pressing member 130 to form a shape, and holes are opened at locations of the first fiber web 100 corresponding to the protrusions 121, thereby forming an uneven open-pore fiber web 101 having an open surface on the pressing member 130 side. (II) A process in which, after removing the pushing member 130 from the support 120, air W1 is blown onto the porous fiber web 101 to push the fibers on the surface of the protrusions along the wall surfaces of the protrusions and orient them in a planar direction. (III) A step of blowing first hot air W2 onto the porous web 101 to fuse the fibers together to obtain porous nonwoven fabric 102. (IV) A step of supplying the second fiber web 103 and laminating it on the porous surface side of the porous uneven nonwoven fabric 102. (V) A heat-sealing step of blowing second hot air W3 to fuse the fibers of the porous nonwoven fabric 102 and the second fibrous web 103 together and to fuse the fibers in the second fibrous web 103 together.

[0071] The first fibrous web 100 is a precursor of the first fibrous layer M1 in the nonwoven fabric 20 and contains thermoplastic fibers. The second fibrous web 103 is a precursor of the second fibrous layer M2 in the nonwoven fabric 20 and contains thermoplastic fibers. The "fiber webs" of the first fibrous web 100 and the second fibrous web 103 refer to fibrous aggregates in which constituent fibers, including thermoplastic fibers, are loosely entangled without being fused and fixed, and which do not retain their shape as a sheet by themselves. In other words, they are fibrous aggregates before being made into a nonwoven fabric. Therefore, the mobility between fibers in the fibrous web is high, and the fibrous web is highly deformable in the pushing process. Such first fibrous web 100 and second fibrous web 103 are each supplied from a carding machine (not shown) to a predetermined thickness.

[0072] In step (I), as shown in FIG. 8(A), a pressing member 130 is used to directly press the first fibrous web 100 on the support 120 with mechanical pressure. This forms an uneven, porous fibrous web 101 that will become the first fibrous layer M1 in the nonwoven fabric 20. This type of shaping can form walls that are perpendicular to the plane of the nonwoven fabric, compared to pressing with non-mechanical pressure such as wind. Furthermore, a strong pressing force is not required to increase the unevenness in the height difference formed in the first fibrous web 100, and the first fibrous web 100 can be shaped softly. Furthermore, fiber disorder can be suppressed, improving shaping properties.

[0073] The support 120 is, for example, drum-shaped and has protrusions 121, for example, as shown in FIG. 8(A), on its peripheral surface. On the peripheral surface of the support 120, a plurality of protrusions 121 are arranged at intervals in one direction (first direction D1) and a direction perpendicular thereto (second direction D2), as shown in FIG. 9, for example. A plurality of protrusions 121 are arranged in the first direction D1 to form a plurality of protrusion rows 121A, which are arranged spaced apart from each other in the second direction D2. The protrusions 121 have spires 122 at their tips. These spires 122 form the apertures 3 in the bottom portion 12 of the first fiber layer M1. The planar shape of the projection 121 as viewed from the spire 122 side is not limited to a rectangle as shown in Fig. 9, but may take various forms, such as a circle, an ellipse, or a diamond. The recess 125 has first recesses 125A extending in the first direction D1 between the protrusion rows 121A, 121A, and second recesses 125C located between the protrusions 121, 121 in the protrusion row 121A. The second recesses 125C are connected to adjacent first recesses 125A. Furthermore, with respect to the protrusion rows 121A adjacent to each other across a first recess 125A, the second recesses 125C in one protrusion row 121A correspond to the second recesses 125C in the other protrusion row 121A in a staggered arrangement. As a result, the second recesses 125C extend intermittently in the second direction D2 via the first recesses 125A and the protrusions 121.

[0074] In the support 120, a plurality of protrusions 121 are arranged corresponding to positions where the apertures 3 are to be formed in the bottom portion 12 of the first fiber layer M1 of the nonwoven fabric 20. Second recesses 125C between the protrusions 121, 121 in the protrusion row 121A are located at positions where the saddle portions 15 of the first fiber layer M1 of the nonwoven fabric 20 are formed. In other words, the protrusion row 121A is located at a position that will become the band regions 16 between the ribs 11, 11 in the first fiber layer M1 of the nonwoven fabric 20. The first recesses 125A are located at positions that will become the ribs 11 in the first fiber layer M1 of the nonwoven fabric 20. The bottom of each recess 125 has a structure that allows hot air to pass through, and for example, a plurality of holes are provided (not shown).

[0075] The pushing member 130 is, for example, in the form of a roll, and has, on the circumferential surface of the roll, pushing portions 131, for example, as shown in Fig. 8(A). On the circumferential surface of the roll of the pushing member 130, a plurality of pushing portions 131 that are continuous in the first direction D1 are arranged at intervals in the second direction D2, for example, as shown in Fig. 10. Between the pushing portions 131, 131, recesses 132 that are continuous in the first direction D1 are formed. The pushing portion 131 of the pushing member 130 corresponds to the first recess 125A of the support body 120. The recess 132 of the pushing member 130 corresponds to the protrusion row 121A of the support body 120. The bottom of the recess 132 of the pushing member 130 has a structure that allows hot air to pass through, and for example, a plurality of holes are arranged therein (not shown).

[0076] The height of the pushing portion 131 of the pushing member 130 is preferably 1 mm or more so that it can be inserted sufficiently between the protrusions 121 of the support 120 .

[0077] The first direction D1 and second direction D2 in the support 120 and the pushing member 130 are preferably the machine direction (MD) and the cross direction (CD) perpendicular to the machine direction in the manufacturing process. The machine direction and the cross direction in the manufacturing process preferably correspond to one direction Y and a direction X crossing the one direction Y in the nonwoven fabric 20, and preferably correspond to the longitudinal direction and the cross direction in an absorbent article including the nonwoven fabric 20. However, the first direction D1 and the second direction D2 are not limited to these.

[0078] In step (I), the protrusions 121 of the support 120 are inserted into the recesses 132 of the pushing member 130. The pushing portion 131 of the pushing member 130 is inserted into the first recess 125A of the support 120 (FIGS. 8(A) and 11). This pushing between the support 120 (FIG. 9) and the pushing member 130 (FIG. 10) forms the porous fibrous web 101, and the uneven shape of the first fiber layer M1 can be suitably formed. The first fiber web 100 is pressed into the first recess 125A of the support 120 by the pressing portion 131 of the pressing member 130 to form a shape. This portion becomes the rib portion 11 in the first fiber layer M1 of the nonwoven fabric 20. At this time, between the protrusions 121 of the support 120 and the pressing portion 131 of the pressing member 130, the fibers of the first fiber web 100 are shaped into a vertically standing shape along the thickness direction. The shaped fibers are not fused and have high mobility, so they are oriented in the thickness direction. This portion becomes the wall portion 11B of the rib portion 11 in the first fiber layer M1 of the nonwoven fabric 20 after undergoing step (II) described below. Meanwhile, at the positions of the protrusions 121 of the support 120, the fibers of the first fibrous web 100 are pushed up to the bottom of the recesses 132 of the pushing member 130 and perforated. This portion becomes the perforated portion 3 of the bottom portion 12 of the first fiber layer M1 of the nonwoven fabric 20. The second recesses 125C between the protrusions 121, 121 in the protrusion row 121A of the support 120 correspond to the recesses 132 of the pushing member 130, so the pushing portion 131 does not enter the second recesses 125C. However, the pushing force of the pushing portions 131, 131 of the pushing member 130 acts on both sides of the fibers of the first fiber web 100 in the second recesses 125C of the protrusion row 121A. Due to this action, the fibers of the first fiber web 100 in the second recesses 125C are stretched in the second direction D2 by the pushing portions 131, 131 on both sides and pushed in the thickness direction, thereby shaping the fibers in the thickness direction and changing the fiber orientation. This portion becomes the saddle portion 15 in the first fiber layer M1 of the nonwoven fabric 20 through step (II), which will be described later. The saddle portion 15 has a top portion 15A and a wall portion 15B, and the wall portion 15B is similar to the wall portion 11B of the ridge portion 11.

[0079] The height of the protrusions 121 of the support 120 and the height of the pushing portion 131 of the pushing member 130 are determined appropriately depending on the thickness of the nonwoven fabric 20 to be manufactured, etc. For example, it is preferably 2 mm or more, more preferably 3 mm or more, even more preferably 5 mm or more, and preferably 15 mm or less, more preferably 10 mm or less, and even more preferably 9 mm or less. Specifically, it is preferably 2 mm or more and 15 mm or less, more preferably 3 mm or more and 10 mm or less, and even more preferably 5 mm or more and 9 mm or less.

[0080] Next, in step (II), as shown in Fig. 8(B), air W1 is blown onto the porous fibrous web 101. This blowing pushes the fibers on the surfaces of the protrusions 121, such as (i) the fibers remaining on the tops of the protrusions 121 and (ii) the fibers shaped in the thickness direction along the wall surfaces of the protrusions 121, along the wall surfaces of the protrusions 121. The pushed-in fibers are pressed down by the air W1, so that they are laid down from the direction along the protrusions 121 and oriented in the planar direction. For example, in the state where the fiber layer is shaped and perforated in step (I), the height of the fiber layer (the layer corresponding to the wall portion) that was pressed and shaped by the protrusion 121 is not uniform around the perforation at the tip, as shown in Figures 12(A) and (B), and the fibers fluff around the perforation, with some fibers leaning toward the perforation. In contrast, by blowing air W1 in step (II), the height of the shaped fiber layer is uniform, and fluffing around the perforation is suppressed, thereby straightening out the disorder of the fibers and forming a neat ring, as shown in Figures 12(C) and (D). As a result, through the step (III) described below, wall portions 11B and 15B in which the constituent fibers are oriented in the planar direction are formed.

[0081] The unevenly perforated fibrous web 101 is in a bulky state in which the interfiber distances have been increased by the uneven shaping in step (I). The fibers pushed in step (II) have their interfiber distances reduced by fiber movement, resulting in a higher fiber density. As a result, the fiber density of the wall portions 11B and 15B in the nonwoven fabric 20 is higher than the fiber density of the apex portions 11A and 15A.

[0082] Furthermore, the fiber layers pressed into the first recesses 125A and second recesses 125C of the support 120 in step (I) are further pressed by blowing air W1 in step (II) to align the pressed positions with each other, thereby making the heights of the ridges 11 and saddles 15 in the thickness direction of the nonwoven fabric 20 equal.

[0083] The air W1 can be blown by a commonly used means, for example, an air duster gun or a hot air generator.

[0084] From the viewpoint of more clearly orienting the constituent fibers in the planar direction, it is preferable that the air W1 be blown from directly above the porous fibrous web 101 formed along the support 120. Specifically, the blowing angle of the air W1 with respect to the planar direction of the porous fibrous web 101 is preferably 45 degrees or more.

[0085] The temperature of the air W1 is set to be below the melting point of the constituent fibers of the porous fibrous web 101. Considering the typical fiber materials used in this type of product, the temperature of the air W1 is preferably 10°C or less lower than the melting point of the constituent fibers (thermoplastic fibers) of the porous fibrous web 101, and more preferably 20°C or less lower. From the viewpoint of efficiently forming wall portions in which the fibers are oriented in a planar direction, the wind speed of the air W1 is preferably 1 m / s or more, more preferably 2 m / s or more, and even more preferably 3 m / s or more. From the viewpoint of maintaining a good texture of the porous fibrous web 101, the wind speed of the air W1 is preferably 100 m / s or less, more preferably 90 m / s or less, and even more preferably 80 m / s or less. The blowing time of the air W1 is preferably 0.2 seconds or more, more preferably 0.5 seconds or more, and even more preferably 1.0 seconds or more, from the viewpoint of increasing the fiber density of the wall portions 11B and 15B.

[0086] 8(C), a first hot air stream W2 is blown onto the nonwoven fabric 101. This fuses the fibers in the porous nonwoven fabric 101 together to form the porous nonwoven fabric 102. The porous nonwoven fabric 102 becomes the first fiber layer M1 of the nonwoven fabric 20.

[0087] The temperature of the first hot air W2 is set to be equal to or higher than the melting point of the constituent fibers of the porous fibrous web 101. Considering the typical fiber materials used in this type of product, the temperature of the hot air W2 is preferably 0°C to 70°C higher than the melting point of the constituent fibers (thermoplastic fibers) of the porous fibrous web 101, and more preferably 5°C to 50°C higher. For example, the temperature of the first hot air W2 is preferably 120°C or higher, more preferably 130°C or higher, and even more preferably 135°C or higher. Furthermore, from the viewpoint of further improving the shape retention of the nonwoven fabric, the temperature of the first hot air W2 is preferably 180°C or lower, more preferably 170°C or lower, and even more preferably 160°C or lower. The wind speed of the first hot air W2 is preferably 0.2 m / s or more, and more preferably 0.3 m / s or more, from the viewpoint of successfully forming a nonwoven fabric from the porous fibrous web 101. The wind speed of the hot air W2 is preferably 50 m / s or less, and more preferably 30 m / s or less, from the viewpoint of further increasing the softness of the nonwoven fabric 20 and successfully forming the hollow regions 1C (11C, 15C). The blowing time of the first hot air W2 is preferably 0.1 seconds or more, more preferably 0.2 seconds or more, and even more preferably 0.3 seconds or more, from the viewpoint of forming a sufficient thermally bonded joint.

[0088] Next, in step (IV), the second fibrous web 103 is supplied and laminated onto the porous side of the porous nonwoven fabric 102 (FIG. 8(D)). For example, the porous nonwoven fabric 102 formed by blowing the first hot air W1 is separated from the drum circumferential surface of the support 120, and the porous nonwoven fabric 102 is laminated onto the second fibrous web 103 being transported by a belt conveyer, with the side on which the porous portions 3 are formed by the protrusions 121 facing downward.

[0089] Next, in step (V), a second hot air W3 is blown to fuse the fibers of the porous nonwoven fabric 102 and the second fibrous web 103, and to fuse the fibers of the second fibrous web 103 (FIG. 8(E)). This integrates the porous nonwoven fabric 102 and the second fibrous web 103, and simultaneously turns the second fibrous web 103 into a nonwoven fabric. This nonwoven fabric of the second fibrous web 103 becomes the second fiber layer M2 of the nonwoven fabric 20. At this time, as shown in Figure 8 (E), the second fibrous web 103 is pressed in by blowing a second hot air stream W3 from the side of the second fibrous web 103. The pressed second fibrous web 103 enters the area partitioned by the wall portions 11B and 15B through the apertures 3 of the porous nonwoven fabric 102, forming the raised portions 5. The raised portions 5 are formed at the aforementioned ratio (H2 / H1) by blowing the second hot air stream W3 after the air W1 blowing process in step (II) as described above. That is, by blowing the air W1, the height of the fiber layer formed in step (I) is made uniform, and the disorder of the fibers is straightened out by suppressing fuzzing around the apertures, and a neat ring is formed. Therefore, in the porous fibrous web 101 and the porous nonwoven fabric 102, fibers are prevented from entering the holes, and the spaces around the holes are clearly enlarged, making it easier for the second fibrous web 103 to enter. In this state, the second hot air W3 is blown from the side of the second fibrous web 103, so that the second fibrous web 103 smoothly enters the spaces partitioned by the wall portions 1B through the holes, forming bulky and thick raised portions 5. At this time, the above-mentioned intra-convex raised portions 8 (not shown) may also be formed in the ridge portions 11 and saddle portions 15. At the same time, the wall portions 11B and 15B of the unevenly apertured nonwoven fabric 102 are integrated with the second fibrous web 103 in the contact areas with the second fibrous web 103, forming fused fiber portions at the intersections of the fibers. The wall portions 11B and 15B also bite into the second fibrous web 103. This biting is caused by the second hot air W3, and is achieved while maintaining the shapes of the wall portions 11B and 15B. Furthermore, the blowing process of the second hot air W2 makes it easy to maintain the shapes (heights) of the wall portions 11B and 15B, and the wall portions 11B and 15B are tightly integrated with the second fibrous web 103 while maintaining the shapes. In this way, the second fiber layer M2 (the nonwoven fabric of the second fiber web 103) is adhered to and integrated with the entire surface (wall portion 11B, wall portion 15B and aperture portion 3) of the uneven open-pore nonwoven fabric 102 (first fiber layer M1), thereby obtaining the aforementioned nonwoven fabric 20.

[0090] Considering the typical fiber materials used in this type of product, the temperature of the second hot air W3 is preferably 0°C to 70°C higher than the melting point of the thermoplastic fibers that make up the porous nonwoven fabric 102 and the second fiber web 103, and more preferably 5°C to 50°C higher. For example, the temperature of the second hot air W3 is preferably 120°C or higher, more preferably 125°C or higher, and even more preferably 130°C or higher. Furthermore, from the viewpoint of better forming the raised portions 5 with a solid structure, the temperature of the second hot air W3 is preferably 160°C or lower, more preferably 150°C or lower, and even more preferably 145°C or lower. The wind speed of the second hot air W3 is preferably 0.5 m / s or more, and more preferably 0.8 m / s or more, from the viewpoint of forming the raised portions 5 (or the raised portions 5 and the intra-convex raised portions 8) with a high volume and a good height, from the viewpoint of fusing the fibers in the second fibrous web 103, and from the viewpoint of fixing the unevenly open-pore nonwoven fabric 102 and the second fibrous web 103 with sufficient strength. Moreover, the wind speed of the second hot air W2 is preferably 10 m / s or less, and more preferably 5 m / s or less, from the viewpoint of forming the raised portions 5 (or the raised portions 5 and the intra-convex raised portions 8) with a high volume and a good height. The blowing time of the second hot air W3 is preferably 0.2 seconds or more, more preferably 0.5 seconds or more, and even more preferably 1.0 second or more, from the viewpoint of fixing the porous nonwoven fabric 102 and the second fibrous web 103 with sufficient strength.

[0091] As described above, the nonwoven fabric of the present invention can be suitably produced by the method for producing a nonwoven fabric of the present embodiment, which includes the above-mentioned steps (I), (II), (III), (IV) and (V).

[0092] In the above manufacturing method, the push-in member 130 is not limited to one having push-in portions 131 that are continuous in the first direction D1 as shown in Fig. 10. For example, the push-in portions 131 may be formed in a lattice pattern, with square-shaped recesses 132 formed between the lattice-shaped push-in portions 131. In this case, the height of the formed saddle portions 15 becomes higher, and the unevenness becomes more distinct.

[0093] The thermoplastic fibers constituting the nonwoven fabric of the present invention can be any of those commonly used as materials for nonwoven fabrics, without any particular limitations. For example, they may be fibers made of a single resin component or composite fibers made of multiple resin components. Examples of composite fibers include core-sheath and side-by-side structures. When using composite fibers containing a low-melting point component and a high-melting point component as the thermoplastic fiber (for example, composite fibers with a sheath-core structure in which the sheath is the low-melting point component and the core is the high-melting point component), the temperature of the hot air blown onto the fiber web in the manufacturing process is preferably equal to or higher than the melting point of the low-melting point component and lower than the melting point of the high-melting point component. More preferably, the temperature is equal to or higher than the melting point of the low-melting point component and 10°C lower than the melting point of the high-melting point component, and even more preferably, the temperature is 5°C or higher than the melting point of the low-melting point component and 20°C or lower than the melting point of the high-melting point component. Furthermore, from the viewpoint of elasticity, the more the core of a sheath-core structure composite fiber is made of a high-melting point component, the higher the elasticity. Therefore, a larger core component in terms of cross-sectional area ratio is preferable. A specific example of a composite fiber with a sheath-core structure in which the sheath is a low-melting point component and the core is a high-melting point component is a composite fiber with a sheath-core structure in which the sheath is made of a polyethylene resin (hereinafter also referred to as PE) and the core is made of a polyethylene terephthalate resin (hereinafter also referred to as PET). Furthermore, in composite fibers with a core-sheath structure, if the resin component of the sheath has a lower glass transition point than the resin component of the core (hereinafter referred to as a low-glass transition point resin component; for example, if the resin component of the core is PET and the resin component of the sheath is PE), the thickness recovery of the nonwoven fabric can be further improved by reducing the mass ratio of the low-glass transition point resin component.

[0094] The nonwoven fabric for absorbent articles of the present invention can be used as a component of various absorbent articles, which broadly include articles used to absorb fluids excreted from the body, such as diapers for adults and babies, sanitary napkins, panty liners, and urine absorption pads.

[0095] An absorbent article having the nonwoven fabric for absorbent articles of the present invention typically comprises a topsheet, a backsheet, and a liquid-retaining absorbent body interposed between the two sheets. In the absorbent article, the nonwoven fabric for absorbent articles of the present invention can be suitably used as the topsheet that comes into contact with the wearer's skin. [Example]

[0096] The present invention will be explained in more detail below based on examples, but the present invention should not be construed as being limited thereto. In these examples, "parts" and "%" are all based on mass unless otherwise specified. "←" means that the value is the same as the value in the left column.

[0097] [Example 1] The nonwoven fabric shown in FIGS. 5 to 7 was produced by carrying out the following steps based on the manufacturing method shown in FIGS. 8(A) to 8(E), and this was used as the nonwoven fabric sample of Example 1. A first fibrous web 100 was produced using core-sheath thermoplastic fibers (polyethylene terephthalate (PET) / polyethylene (PE) = 5:5) with a fineness of 1.3 dtex. The thermoplastic fibers had been subjected to a hydrophilization treatment. The first fibrous web 100 was placed on a support 120, and a pushing member 130 was pushed into the support 120 from above the first fibrous web 100 to perform a shaping treatment, thereby forming an apertured fibrous web 101. Next, air W1 was blown from directly above the apertured fibrous web 101 on the support 120 using an air duster gun, to orient the shaped fibers around the apertures in the planar direction. The temperature of the air W1 was room temperature (25°C), the wind speed was 30 m / s, and the blowing time was 10 seconds. Next, a first hot air stream W2 was blown onto the fabric to carry out a fusion treatment, thereby producing a porous nonwoven fabric 102 (first fiber layer M1). The first hot air stream W2 had a temperature of 160°C, a wind speed of 3.0 m / sec, and a blowing time of 3 seconds. The porous nonwoven fabric 102 thus produced had a basis weight of 30 g / m 2 It was. Next, a second fibrous web 103 made using core-sheath thermoplastic fibers with a fineness of 1.8 dtex was laminated on the porous side of the unevenly open nonwoven fabric 102, and a second hot air stream W3 was blown onto the second fibrous web 103 side to perform a fusion treatment. This produced a laminated nonwoven fabric (first fibrous layer M1 + second fibrous layer M2), which was used as the nonwoven fabric sample of Example 1. The second hot air stream W3 had a temperature of 140°C, a wind speed of 1.5 m / sec, and a blowing time of 3 seconds. The nonwoven fabric sample of Example 1 produced had a basis weight of 70 g / m 2 (First fiber layer M1: 30g / m 2 , second fiber layer M2: 40g / m 2 ) was. In the nonwoven fabric sample of Example 1, the second fiber layer M2 had protrusions 5 on the side facing the first fiber layer M1, extending from the openings 3 of the first fiber layer M1 into the region defined by the wall. The ratio (H2 / H1) of the thickness H2 of the protrusions to the thickness H1 of the protrusions 1 of the first fiber layer M1 was 0.7, the smallest ratio, and was 0.8 or greater for the entire nonwoven fabric sample. The H2 / H1 ratio in Table 1 is the average value obtained by measuring five locations on the nonwoven fabric sample.

[0098] [Comparative Example 1] A nonwoven fabric sample of Comparative Example 1 was produced in the same manner as in Example 1, except that the treatment of blowing air W1 using an air duster gun was not carried out. In the nonwoven fabric sample of Comparative Example 1, which was produced as described above, the ratio of the thickness H2 of the protrusions to the thickness H1 of the first fiber layer M1 (H2 / H1) was less than 0.6, more specifically, 0.55 or less. The H2 / H1 ratios in Table 1 are the average values ​​measured at five points on the nonwoven fabric sample to be measured.

[0099] Comparative Example 2 A nonwoven fabric sample of Comparative Example 2 was produced in the same manner as in Example 1, except that the second fiber web 103 was not laminated, steps (IV) and (V) were not performed, and steps (I) to (III) were performed. The nonwoven fabric sample of Comparative Example 2 consisted only of the unevenly perforated nonwoven fabric 102 (first fiber layer M1), and the longitudinal orientation rate of the fibers in wall portion 11B was 65%, and the longitudinal orientation rate of the fibers in wall portion 15B was 63%, meaning that both wall portions were longitudinally oriented.

[0100] Comparative Example 3 A nonwoven fabric sample of Comparative Example 3 was prepared in the same manner as Comparative Example 2, except that the protrusions 121 on the support 120 did not have spires 122 at their tips. The nonwoven fabric sample of Comparative Example 3 consisted only of the first fiber layer M1, did not have any openings 3 penetrating in the thickness direction, and had a longitudinal fiber orientation rate of 63% in wall portion 11B and 64% in wall portion 15B, meaning that both wall portions were longitudinally oriented.

[0101] Comparative Example 4 The porous nonwoven fabric 102 (basis weight 30 g / m) produced in Example 1 2 On the open side of the sheet, melt-blown fibers prepared using the melt-blown nonwoven fabric manufacturing apparatus described in paragraphs

[0063] to

[0073] of the specification of JP-A-2022-174680 were deposited to prepare a nonwoven fabric sample of Comparative Example 4. The production conditions for the melt-blown fibers were as follows: <Resin composition> Polypropylene homopolymer (MFR: 1200g / min) 100 parts <Manufacturing equipment> Spinning nozzle diameter: 0.15mm Spinning nozzle pitch: 0.25mm Resin temperature: 260℃ ·Single hole discharge amount: 0.06g / min / hole Total resin output: 14.4 kg / hr / m Hot air temperature: 265℃ Total hot air volume: 750Nm3 / hr / m <Nonwoven fabric> Weight: 10g / m 2 In the nonwoven fabric sample of Comparative Example 4, the first and second fiber layers were not fused together, and a laminated nonwoven fabric could not be formed.

[0102] Comparative Example 5 A nonwoven fabric sample of Comparative Example 5 was produced in the same manner as in Comparative Example 4, except that the unevenly porous nonwoven fabric 102 was not used. The nonwoven fabric sample of Comparative Example 5 consisted only of a melt-blown nonwoven fabric corresponding to the second fiber layer M2 without the raised portions 5.

[0103] Comparative Example 6 A nonwoven fabric sample for Comparative Example 6 was produced in the same manner as in Example 1, except that the unevenly porous nonwoven fabric 102 was not used. The nonwoven fabric sample for Comparative Example 2 consisted only of the second fiber layer M2 without the raised portions 5, and had a basis weight of 30 g / m 2 It was.

[0104] The nonwoven fabric samples of Example 1 and Comparative Examples 1 to 6 were subjected to the following measurements for thickness, softness, smoothness and design properties.

[0105] <Thickness> 4.9 mN / cm (similar to the method for dividing the fiber layer of the wall portion 1B) 2 A load was applied, and the thickness was measured under the load using a laser displacement meter by the following method. The nonwoven fabric sample to be measured was cut into a 10 cm x 10 cm piece to prepare a measurement sample. A laser thickness meter (Omron Corporation, high-precision displacement sensor ZS-LD80 (product name)) was used to measure the thickness of the measurement sample using a flat plate. 2 The load was applied, and the thickness was measured in that state. Measurements were taken at three locations, and the average value was taken as the total thickness of the nonwoven fabric sample being measured. <Softness> Compression property evaluation To measure the thickness deformation, a KES compression tester (KES FB-3 manufactured by Kato Tech Co., Ltd.) was used. The nonwoven fabric sample was compressed at 50 gf / cm in normal mode except that the terminal speed was set to 0.1 mm / s. 2 The compression characteristics were evaluated up to 1000 kJ / min, and the displayed WC was read. Measurements were taken at three points within the nonwoven fabric sample, and the average value was calculated. This was done three times, and the average value was used as the WC value. The WC value indicates the energy required for compression per unit area, and the larger the WC value, the easier it is to compress and the softer it is.

[0106] <Smoothness> For one side of each nonwoven fabric sample, 20T, an automatic surface testing machine (KES FB4-AUTO-A manufactured by Kato Tech Co., Ltd.) was used to measure the surface roughness using a probe made of a 0.5 mm diameter steel piano wire with a probe area of ​​1 cm. 2 , load 50gf / cm 2 The friction force was measured when the sheet was moved back and forth over a length of 30 mm at a speed of 1 mm / s. The analysis distance was set to 20 mm by cutting 5 mm of data from both ends. The coefficient of surface friction was calculated as MIU, and the mean deviation of the coefficient of surface friction was calculated as MMD. The measurement surface was set so that the surface side faced the probe, and the measurement directions were the aforementioned directions X and Y, and the measured values ​​were averaged. The initial sample tension was 10 gf / cm. Each measurement value was calculated by measuring five points on the sheet and averaging the results. Nonwoven fabrics can provide a pleasant feel by having appropriate friction. From this viewpoint, the surface friction coefficient (MIU, average friction coefficient) is preferably 0.1 or more, more preferably 0.2 or more. This allows for a soft fibrous feel, rather than a smooth film-like feel. Furthermore, from the viewpoint of preventing the fabric from sticking to the skin and causing no damage to the skin, the surface friction coefficient (MIU, average friction coefficient) is preferably 0.5 or less, more preferably 0.4 or less, and even more preferably 0.3 or less. When the coefficient of surface friction (MIU, mean coefficient of friction) is within the appropriate range and the mean deviation of the coefficient of surface friction (MMD) is small, the fabric tends to feel moderately smooth. Nonwoven fabrics with moderate smoothness can be made to feel good to the touch. From this perspective, the mean deviation of the coefficient of surface friction (MMD) is preferably 0.001 or more, and more preferably 0.002 or more. Furthermore, the smaller the friction, the less likely it is to get caught even if the surface is uneven, and the smaller the fluctuation in the coefficient of friction, making the fabric feel smooth. From this perspective, the mean deviation of the coefficient of surface friction (MMD) is preferably 0.01 or less, and more preferably 0.008 or less.

[0107] <Design 1> Measurement of patterns using image analysis The plane of one side (20T) of each nonwoven fabric sample was imaged, and the image was analyzed. Specifically, each nonwoven fabric sample was cut into a 10 cm square, placed on a black backing, and image data of the plane of one side (20T) was acquired using the scanner function of a copier (RICOH, model number: MPC5504) (Figures 13(A) to 13(F)). The acquired images were then analyzed. The scanner was set to a resolution of 600 dpi, and the PDF files were imported into a personal computer (Microsoft Windows 10). Next, the PDF files were converted into JPEG files using image conversion software, and the JPEG files were opened using Paint software (Microsoft Windows 10, version: 22H2 (OS build: 19045, 3930)). Next, the image conversion function of Paint software was used to acquire the image data, which was converted into a 16-color bitmap file. In this case, the top of the first fiber layer is displayed in white, and the open pores are displayed in gray or black (Figures 14(A) to 14(F)). From the image analysis, the gray or black areas (the areas with the bulky protrusions 5 in the nonwoven fabric sample) in the image of the nonwoven fabric sample were defined as the pattern. 2 The above pattern part is 25cm 2 If there were four or more patterns in the range, it was judged to have a design. For the black backing paper, Fuji Kyowa Paper Co., Ltd.'s "Kenran (black) ream weight 265g" was used.

[0108] <Design 2> Sensory evaluation of design A commercially available baby diaper (product name "Merry's First Premium S Size," manufactured by Kao Corporation in 2023) with the topsheet removed was used as an absorbent core, and nonwoven fabric cut out to 100 x 250 mm from each nonwoven fabric sample of the Examples and Comparative Examples was layered on the absorbent core. The nonwoven fabrics were layered with the second fiber layer facing the absorbent core, and the periphery of the layered nonwoven fabrics was fixed to prepare diapers for evaluation. The design of the nonwoven fabrics was evaluated by three researchers (in their 20s and 30s) engaged in nonwoven fabric research and development, who performed a sensory evaluation on a 5-point scale to determine whether a highly visible pattern was formed on the nonwoven fabric (topsheet), and the average values ​​were compiled. The sensory evaluation was conducted by leaving the evaluation diaper stationary and visually observing the nonwoven fabric from above. A mean score of 3.5 points or higher, preferably 4.0 points or higher, was considered to be a highly visible pattern from the one side (20T) of the surface (20T). (Sensory evaluation criteria) 5: The entire surface of the sheet appears to have a highly visible pattern. 4: The entire surface sheet appears to have a mixture of highly visible and low-visibility patterns. 3: The entire surface of the sheet appears to have a pattern that is difficult to see. 2: Only a small portion of the surface sheet has a pattern that is difficult to see, and most of it appears to have no pattern. 1: It seems like there is no pattern on the surface sheet.

[0109] [Table 1]

[0110] As shown in Table 1, the nonwoven fabric sample of Example 1 was 0.6 times thicker than the nonwoven fabric sample of Comparative Example 1 and had a WC value equivalent to that of the nonwoven fabric sample of Comparative Example 1, and therefore, although thinner, the nonwoven fabric sample of Example 1 had equivalent softness to the nonwoven fabric sample of Comparative Example 1. Furthermore, the nonwoven fabric sample of Example 1 had a higher WC value than the nonwoven fabric samples of Comparative Examples 2 to 6, and therefore had excellent softness. At the same time, the nonwoven fabric sample of Example 1 had a lower MIU than Comparative Examples 1 to 6, and therefore was very smooth when stroked with a finger, and also had a lower MMD than Comparative Examples 1 to 6, and therefore was a nonwoven fabric with a smooth feel with little sense of surface irregularities. From the above, Example 1 was a nonwoven fabric that combined the softness of an uneven nonwoven fabric with the smooth, even feel when stroked with a surface due to the raised portions. In addition, the nonwoven fabric sample of Example 1 had an area of ​​1 mm 2 The black part above is 25mm 2 There were 20 pieces in the range of 0.01 to 0.01, confirming the high measured value of the aforementioned design property 1. Furthermore, the nonwoven fabric sample of Example 1 had a low fiber density at the apex 5A of the raised portion, a continuous change in fiber density toward the depression 6, and a discontinuous change in fiber density between the walls 11B and 15B and the bottom 7 of the raised portion 5. Therefore, the evaluation value of design property 2 was about 1.7 times higher than that of each of the comparative examples, and the nonwoven fabric had a highly visually visible pattern and a highly designed design. As described above, the nonwoven fabric sample of Example 1 was both soft and smooth, while also exhibiting enhanced design properties. [Explanation of symbols]

[0111] M1 First fiber layer M2 2nd fiber layer 1 Convex part 1A Top 1B Wall section 1C hollow area 1D base 2 bottom 2U Convex part to concave part 3 Opening part 5 Protuberance 6. Recess 7 Hem 8. Protuberance inside the convex part 10, 20 Nonwoven fabric 10T, 20T One side 10B, 20B other side

Claims

1. A nonwoven fabric having a first fiber layer and a second fiber layer laminated in a thickness direction, and including fused fiber portions at intersections of the fibers, the first fiber layer has a concave-convex structure including a plurality of convex portions and a bottom portion provided between adjacent convex portions, each of the plurality of convex portions including a top portion and a wall portion supporting the top portion, and the bottom portion has an opening portion penetrating through in the thickness direction; The second fiber layer is provided on the side of the first fiber layer where the bottom portion is located, the second fiber layer has, on a surface facing the first fiber layer, raised portions extending from the openings of the first fiber layer into the regions defined by the wall portions, a ratio (H2 / H1) of a thickness H2 of the raised portion to a thickness H1 of the first fiber layer is 0.6 or more and 1 or less; Nonwoven fabric for absorbent articles.

2. The nonwoven fabric for absorbent articles according to claim 1 , wherein the fibers of the wall portion of the first fibrous layer are oriented in a planar direction.

3. the raised portion in the second fiber layer has a base portion located at the base of the wall portion; The nonwoven fabric for absorbent articles according to claim 1 or 2, wherein the skirt portion has a fiber density different from that of the wall portion.

4. The area of ​​the opening is 10 mm ２ 60mm or more ２ 3. The nonwoven fabric for absorbent articles according to claim 1 or 2, wherein:

5. 3. The nonwoven fabric for absorbent articles according to claim 1, wherein the second fibrous layer has a continuous fibrous layer extending in a planar direction on the surface thereof facing the first fibrous layer.

6. the raised portion in the second fiber layer has a raised apex located at a apex in the thickness direction, 3. The nonwoven fabric for absorbent articles according to claim 1, wherein the fiber density of the raised peaks is lower than the fiber density of the peaks in the first fiber layer.

7. the raised portion in the second fiber layer has a raised apex located at a apex in the thickness direction, 3. The nonwoven fabric for absorbent articles according to claim 1, wherein the fiber density of the raised peaks is lower than the fiber density of the wall portions of the first fiber layer.

8. the second fiber layer has a recessed portion into which a base portion of the wall portion bites, The raised portion in the second fiber layer has a bottom portion located at the base of the wall portion and a top portion located at the top in the thickness direction, 3. The nonwoven fabric for absorbent articles according to claim 1, wherein the fiber density of the raised peaks is lower than the fiber density of the bottoms and the fiber density of the recesses.

9. When viewed from above from the first fiber layer, the basis weight of the region where the first fiber layer is located is 10 g / m higher than the basis weight of the protruding portion of the second fiber layer. ２ The nonwoven fabric for absorbent articles according to claim 1 or 2, having a tensile strength of at least 1000 MPa.

10. The number of the raised portions is 4 per 25 cm ２ The nonwoven fabric for absorbent articles according to claim 1 or 2, wherein the nonwoven fabric is as described above.

11. Weight per unit area is 20g / m ２ 120g / m or more ２ 3. The nonwoven fabric for absorbent articles according to claim 1 or 2, wherein:

12. 4.9 mN / cm ２ 3. The nonwoven fabric for absorbent articles according to claim 1, which has a thickness under load of 0.5 mm or more and 15 mm or less.

13. An absorbent article comprising the nonwoven fabric for absorbent articles according to claim 1 or 2.

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