Nonwoven fabric manufacturing method

Abstract

To provide a production method of uneven nonwoven fabric, capable of imparting an excellent uneven shape with web floating from a substrate suppressed.SOLUTION: A production method of uneven nonwoven fabric includes shaping a web of aggregate containing fiber by engaging a substrate having protrusions or concavities with an indenter having an indenting portion engageable with the substrate. The peeling resistance force per unit area in peeling of the shaped web from the substrate is controlled to 300 cN / m2 or more and 20000 cN / m2 or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a nonwoven fabric. [Background technology]

[0002] Conventionally, various manufacturing methods have been disclosed for producing nonwoven fabrics having an uneven shape having recesses and protrusions. For example, Patent Document 1 describes a method for producing a textured nonwoven fabric in which an unfused fiber web is placed on a support having protrusions, the fiber web is pressed into shape using a pressing member, and the fibers are thermally fused together using hot air. A method for roughening the support protrusions is described in order to increase the amount of fiber remaining on the top of the support protrusions by increasing the hooking ability of the fibers and to prevent the fibers from becoming partially thin, and specifically, it is described that the roughening treatment may be performed on only a part of the top, only the entire top, or from the top to a part of the upper part of the wall surface. When considering the hooking ability of the fibers and the ease of the fibers following the wall surface, it is preferable that the entire top of the support protrusions is roughened, and when considering the ease of peeling after nonwoven fabric formation, it is described that it is preferable that only the top is roughened and the wall surface is not roughened. Patent Document 2 describes a method for producing a concave-convex nonwoven fabric in which an unfused web is engaged and shaped using a male support member and a female support member, and then the fibers are thermally fused together using hot air. This method describes that by reducing the surface roughness of the female support member, the female support member can be smoothly removed without the fibers clinging to it. In the method for producing a nonwoven fabric described in Patent Document 3, a support for shaping is disposed on the outer periphery of a drum, and a suction unit is disposed inside the drum. It is described that the suction unit applies negative pressure to the fiber web disposed on the support, making it easier for the fibers of the fiber web to conform to the circumferential surface of the support. Patent Document 4 describes a method for producing a thick fleece web or raised film by shaping an unstructured web using a male roll and a female roll, and describes that a hot roll is disposed on the surface of the male roll so as to prevent the web from sticking to the surface. Patent Document 5 describes a method for manufacturing a topsheet in which an upper layer is formed with projections and recesses by meshing first and second rolls, and then bonded to a lower layer. It also describes that suction ports are formed in the tooth grooves of each gear in the first roll, and the upper layer formed with projections and recesses is brought into close contact with the circumferential surface of the first roll by the suction force of the suction ports. Patent Document 6 describes a method for forming a nonwoven fiber sheet by bonding a randomly oriented nonwoven web, which has no internal adhesion other than friction between fibers, to a molten backing layer. It describes that the first corrugating member used in the forming has a rough finish (formed, for example, by sandblasting) and the second corrugating member has a smooth polished finish, and the nonwoven fiber sheet is preferentially attached along the surface of the first corrugating member. It also describes that the ridges on both corrugating members can be oriented in the range of 0° (parallel to the axis) to 90° with respect to the axis. Patent Document 7 describes a method for manufacturing a topsheet in which an upper layer is formed with projections and recesses by meshing first and second rolls, and then bonded to a lower layer. It describes that a locking material is disposed in the recesses of the first roll, and a part of the pressed sheet-like material is mechanically locked, thereby preventing the upper layer from floating up from the circumferential surface of the first roll. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-112748 A [Patent Document 2] JP 2020-000467 A [Patent Document 3] JP 2019-112747 A [Patent Document 4] Special Publication No. 2002-531726 [Patent Document 5] JP 2004-174234 A [Patent Document 6] Special Publication No. 2001-522700 [Patent Document 7] JP 2010-111003 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a conventional method for producing a nonwoven fabric having a concave-convex shape, after concave-convex shaping is performed by meshing a pair of supports or rolls (hereinafter, supports, etc.), the web may return from being pressed into the support, etc., and float up. If the web returns to being pressed, it becomes difficult to obtain a shaped nonwoven fabric with a high concave-convex height. This phenomenon is more likely to occur due to centrifugal force, etc., as the processing speed increases, making it difficult to obtain a clean molded pattern. This floating phenomenon can occur when various sheet-like fiber assemblies such as heat-fusible webs before the fibers are heat-fused together and nonwoven fabrics in which the fibers are heat-fused together (hereinafter, in the present invention, these are collectively referred to as webs) are subjected to concave-convex shaping. In this regard, if the return of the web is suppressed by suction as described in Patent Documents 3 and 5, the surface temperature of the support, etc. may drop or temperature unevenness may occur, which may lead to a decrease in processability. If a heating medium is added to maintain the temperature, it will interfere with the suction device, making it difficult to place the heating medium near the support surface and making it difficult to maintain a sufficient temperature. In addition, the suction port is prone to fiber clogging, and furthermore, the suction port effectively reduces the thickness of the support, etc., reducing its strength and making it more likely to bend. In addition, in the above Patent Document 1, it is preferable that the wall surface of the support protrusion is not roughened, and even if it is roughened, it is only from the top to a part of the upper part of the wall surface. There is no consideration to suppress the return of the web due to centrifugal force and the like acting while the web is held on the support. Similarly, the above Patent Document 2 describes the surface roughness of the female member (pushing member), but does not describe the male member (support), and does not consider the suppression of the return of the web due to centrifugal force and the like acting while the web is held on the support. When using hot air treatment as described in the above Patent Documents 1 and 2 simply to suppress the return of the web, there is a problem that increasing the air speed reduces the actual thickness of the web, and increasing the temperature of the hot air hardens the surface of the obtained nonwoven fabric. Therefore, it was difficult to obtain a nonwoven fabric with a good unevenness and a pleasant texture by the conventional manufacturing techniques. In this regard, the above Patent Documents 1 to 4 do not describe a shaping method for suppressing the return of the web. In particular, in the technique described in Patent Document 4, the surface of the male roll (support) is designed to prevent the web from adhering, and the web is more likely to float. In addition, the method described in Patent Document 5 alone is insufficient in terms of the interaction with the web, and is not sufficient to suppress the web from floating due to the centrifugal force during high-speed processing. The above Patent Document 6 describes a rough finish for the first corrugated member corresponding to the support, and the above Patent Document 7 describes the provision of a locking material on the first roll corresponding to the support, but in addition to the same reasons as Patent Document 5, problems such as tearing during peeling occurred when the strength of the web was low, and further detailed consideration was required.

[0005] In view of the above, the present invention relates to a method for producing a concave-convex nonwoven fabric that can impart a good concave-convex shape while suppressing lifting of the web from the support. [Means for solving the problem]

[0006] The present invention relates to a method for forming a web having projections and recesses by engaging a support having a pushing member having a pushing portion that can be engaged with the support, and a method for forming a web having projections and recesses by engaging a pushing member having a pushing portion that can be engaged with the support, the method comprising the steps of: 2 More than 20000cN / m 2 The present invention provides a method for producing a nonwoven fabric having a concave-convex shape as described below. Effect of the Invention

[0007] According to the method for producing a concave-convex nonwoven fabric of the present invention, it is possible to produce a concave-convex nonwoven fabric having a good concave-convex shape while suppressing lifting of the web from the support. [Brief description of the drawings]

[0008] [Figure 1] 1(A) and 1(B) are explanatory views showing an example of a concave-convex shaping step in the manufacturing method for the concave-convex nonwoven fabric of the present invention. [Diagram 2] FIG. 10 is an explanatory diagram showing a schematic diagram of forces acting on a web in a state in which the web is temporarily held in line with the uneven shape of a support by shaping. [Diagram 3] FIG. 2 is a cross-sectional view showing a preferred embodiment of a convex shape on a support together with a web. [Figure 4] FIG. 1A is a perspective view showing a schematic diagram of a micro concave-convex shape arranged on a convex portion of a support, and FIGS. 1B to 1D are cross-sectional views showing specific examples of the micro concave-convex shape. [Diagram 5] 5 is a cross-sectional view showing a schematic view of the meshing amount between the support and the push-in member and the gap distance between the protrusions, together with the web. FIG. [Figure 6] 1A and 1B are explanatory diagrams showing a schematic cross-sectional area projected in the CD direction where the convex portion of the support contacts the web when the support and the pushing member are engaged, in which (A) is a plan view of the convex portion seen from above, and (B) is a side view of the convex portion seen from the side. [Figure 7] FIG. 2 is a perspective view showing a preferred embodiment of a support; [Figure 8]FIG. 8 is a side view of the support shown in FIG. 7 as seen in the CD direction. [Figure 9] FIG. 2 is a cross-sectional view showing a state in which a web having a multi-layer structure is temporarily held along a support. [Figure 10] 1 is a cross-sectional view showing a preferred embodiment of the shape of a pushing portion of a pushing member, together with a support body and a web. FIG. [Figure 11] FIG. 1 is a schematic diagram showing an example of a manufacturing apparatus used in the manufacturing method of the uneven nonwoven fabric of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A preferred embodiment of the method for producing a nonwoven fabric having projections and recesses according to the present invention will be described below with reference to the drawings. In this specification, the conveying direction during the production of a nonwoven fabric is referred to as MD (machine direction), and the width direction perpendicular to the conveying direction is referred to as CD (cross direction).

[0010] The manufacturing method of the uneven nonwoven fabric of the present invention includes a step of forming an uneven shape on a web consisting of an aggregate containing fibers by meshing a support having convex or concave portions with a pushing member having a pushing portion that can mesh with the support.

[0011] The support has a concave-convex shape, can engage with the pushing member, and temporarily holds the nonwoven fabric or heat-sealable web. The above-mentioned convex and concave portions refer to portions that have a relative height difference with each other, for example, portions that protrude higher than the substrate constituting the support are convex portions, and portions between the convex portions are concave portions. In addition, when a portion of the substrate constituting the support that is partially recessed is a concave portion, a portion surrounded by the concave portion is a convex portion (not shown). The support may be flexible, such as in the form of a conveyor or net, or non-flexible, such as in the form of a drum roll or plate. Various materials can be used for the support. For example, resin, metal, carbon, and ceramic can be mentioned. A non-flexible embossing roll is preferable in that it can be embossed heat fusion or embossed pressure bonding on the support. The pushing member has an uneven shape and can be pushed into (engaged with) the support. The pushing member may be flexible or inflexible, and examples of the pushing member include a ring roll, an uneven roll, a net, a belt, a chain, a leaf spring (elastic plate), and a movable load plate. Various materials can be used for the pushing member, and examples of the materials include resin, metal, carbon, and ceramic.

[0012] "Matching so as to be able to mesh" means that the recesses of the support and the pushing portion of the pushing member are arranged in a corresponding manner, and the pushing portion enters the recesses while leaving a gap between the protrusions of the support and the pushing portion of the pushing member that is large enough for the web to enter. In other words, it means that the uneven shape of the support and the uneven shape of the pushing member are matched so as to mesh with each other. At this time, in order to reduce wear and deformation of the support and the pushing member, it is preferable that the support and the pushing member do not come into direct contact with each other.

[0013] The term "peel resistance per unit area" refers to the resistance applied per unit area of ​​a shaped web when the web is peeled from a support or a pushing member. The peel resistance can be measured by the method described below. The term "web" refers to a sheet-like fiber assembly including nonwoven fabric and heat-sealable webs. The web preferably contains thermoplastic fibers as constituent fibers. The term "nonwoven fabric" refers to a sheet in which a fiber assembly is formed by thermal fusion, mechanical entanglement, or chemical bonding (adhesive, chemical bond, etc.). "Heat-fusible web" means an aggregate of unfusible fibers that can be fused by heat (hot air, steam, heat embossing, ultrasonic embossing, etc.), and excludes those that have been mechanically entangled by hydroentanglement or needle punching before the fusion treatment process. More specifically, those that do not have the strength of a nonwoven fabric and have a maximum tensile strength of 100cN / 50mm or less in the MD and CD directions are considered to be heat-fusible webs. For example, card webs are included.

[0014] The above-mentioned "heat-fused" state means that the heat-fusible web melts, and the constituent fibers of the heat-fusible web no longer have the fiber form before the fusion process. Having a fiber form means that the ratio (former / latter) of the length of the fiber to the diameter (calculated as a perfect circle) calculated from the cross-sectional area of ​​the fiber is 300 times or more. For example, in the "heat-fused" state, at least a part of the outer surface of the constituent fibers of the heat-fusible web melts, and the boundary with the outer surface of the other fibers becomes indistinguishable, and the fiber form before the fusion process is no longer retained. When the constituent fibers of the heat-fusible web, such as composite fibers, are made of two or more resins, even if a specific resin does not melt and maintains the fiber form, the other resins melt, and the boundary between the outer surfaces of the constituent fibers of the heat-fusible web becomes indistinguishable, and the fiber form before the fusion process is no longer retained. These can be observed by observing the cross section of the fused fiber part with a scanning electron microscope (SEM).

[0015] The fibrous material constituting the web may be any ordinary fiber or heat-stretchable fiber. From the viewpoint of fluffiness and strength, the fibrous material is preferably a continuous fiber, but is not limited thereto and may be a long fiber or a short fiber. Continuous fibers are essentially continuous fibers, except for broken portions of the fibers at the end faces of the product member and some broken fibers in the fuzzed portions, and are found in the spunbond method. The long fibers have an effective fiber length (80 mm or more) and are found in the meltblown process. Staple fibers are fibers less than 77 mm long and are used in air-through nonwovens, spunlace nonwovens, and airlaid nonwovens.

[0016] Examples of methods for supplying heat-fusible webs include the spunbond method (before embossing, continuous fibers), the electrospinning method (continuous fibers), the spunmelt method (a method combining hot air stretching and cold air stretching, long fibers), the meltblown method (long fibers), the carding method (short fibers), and the airlaid method (short fibers). The spunbond method and the carding method are particularly preferred because they produce a bulky three-dimensional shaped nonwoven fabric. It is also possible to combine these supply methods.

[0017] The fiber material preferably contains thermoplastic fibers, and examples thereof include polyolefin fibers such as polyethylene (hereinafter also referred to as PE) fibers and polypropylene (hereinafter also referred to as PP) fibers, and fibers made solely of thermoplastic resins such as polyethylene terephthalate (hereinafter also referred to as PET) and polyamide. It is also possible to use composite fibers of a core-sheath type, side-by-side type, or other structure. In the present invention, it is preferable to use composite fibers. The composite fibers referred to here include core-sheath fibers in which a high melting point component is the core portion and a low melting point component is the sheath portion, and side-by-side fibers in which a high melting point component and a low melting point component are arranged in parallel. A preferred example of such a fiber is a fiber with a core-sheath structure in which the sheath component is polyethylene or low melting point polypropylene, and representative examples of the fiber with the core-sheath structure include fibers with PET (core) and PE (sheath), PP (core) and PE (sheath), PP (core) and low melting point PP (sheath), and the like. More specifically, the above-mentioned constituent fibers preferably contain polyolefin fibers such as polyethylene fibers and polypropylene fibers, polyethylene composite fibers, and polypropylene composite fibers. Here, the composite composition of the polyethylene composite fiber is preferably polyethylene terephthalate and polyethylene, and the composite composition of the polypropylene composite fiber is preferably polyethylene terephthalate and low melting point polypropylene, more specifically, PET (core) and PE (sheath), and PET (core) and low melting point PP (sheath). The melting point of the resin used means the melting point measured under atmospheric pressure (in N2 gas atmosphere) unless otherwise specified.

[0018] These fibers can be used alone or in combination of two or more to form a heat-sealable web. The heat-sealable web may also contain fibers other than thermoplastic fibers, such as natural fibers such as cotton and pulp, and regenerated fibers such as rayon and cupra. Therefore, it is preferable that the nonwoven fabric produced by the production method of the present invention contains the above-mentioned fibers.

[0019] An example of the unevenness forming step in the method for producing an uneven nonwoven fabric of the present invention is shown in Figures 1(A) and (B). That is, as shown in Figure 1(A), a plurality of convex portions 11 are arranged at a predetermined interval on a substrate 13, and a web 30 is placed on a support 10 having concave portions 12 between the convex portions 11. Next, as shown in Figure 1(B), a pushing member 20 is pressed against the web 30 from above. The pushing member 20 has a plurality of pushing portions 21 at a predetermined interval on the substrate 23, and the pushing portions 21 are engaged with the concave portions 12 of the support 10. As a result, the web 30 is partially pushed into the concave portions 12. Accordingly, the convex portions 11 of the support 10 are engaged with the spaces 22 between the pushing portions 21, 21 of the pushing member 20. As a result, the web 30 is partially pushed into the spaces 22. In this way, the web 30 is unevenly shaped.

[0020] The web 30 shaped by the support 10 and the pushing member 20 is conveyed in the conveying direction (MD direction) while being held along the uneven shape of the support 10. During the conveying process after shaping, a heat fusion process or a pressure bonding process is performed between the fibers to fix the uneven shape of the web, and an uneven nonwoven fabric is formed. This heat fusion process or pressure bonding process can be performed by various methods that can fuse or press, preferably press, the fibers in the nonwoven fabric together, for example, hot air treatment, embossed heat fusion process, and embossed pressure bonding process. These can be performed alone or in combination, but it is preferable to perform hot air treatment after embossed heat fusion process or embossed pressure bonding process, because it can heat fusion the fibers together in the shaped state, and even if the shaped shape is crushed by pressure in the finished nonwoven fabric, the shape is easily restored when the pressure is released. The embossing heat fusion processing step and the embossing pressure bonding processing step may be carried out simultaneously with the shaping process using the support 10 and the pressing member 20, or may be carried out using a point joining means (not shown) on the web 30 that has been temporarily held on the support 10 after the shaping process. Also, other sheets may be laminated onto the shaped web to form an integrated structure.

[0021] The obtained uneven nonwoven fabric can be applied to, for example, the top sheet of absorbent articles such as sanitary napkins and disposable diapers, the back sheet on the clothing side, the sweat absorbent sheet, the wings of sanitary napkins, etc. When used as a top sheet, either side may be used facing the wearer's skin. An example of a diaper has a top sheet, a back sheet on the clothing side, an absorbent sandwiched between the top sheet and the back sheet, and further has side leakage prevention gathers formed by the side sheets. The diaper may be a tape type or a pants type that is worn by fixing the fastening tape on the back side to the abdominal side. In addition, it can be applied to various absorbent articles other than diapers, such as sanitary napkins.

[0022] In the method for producing a nonwoven fabric of the present invention, the support and web are configured as follows when shaping is performed. This makes it possible to produce a nonwoven fabric with a good uneven shape by suppressing the web from floating up from the support after shaping.

[0023] First, regarding the support, the peel resistance per unit area when peeling the shaped web from the support (hereinafter also referred to as the support peel resistance E1) is 300 cN / m 2 More than 20000cN / m 2 The following is the case. This can prevent the shaped web from floating up due to the centrifugal force accompanying the transport after shaping. Also, it can prevent the web, once shaped by the support, from returning to a flat shape before being heat-sealed or pressure-bonded, from floating up from the support. Therefore, the uneven shape of the web at the time when the pushing portion of the pushing member is engaged with the recess of the support is easily maintained. Since the uneven shape at the time of shaping can be well maintained, the uneven shape is less likely to be disturbed from the web shaping process to the heat-sealing or pressure-bonding process, and the uneven shape at the time of shaping can be well fixed. At this time, suction or blowing with a fluid to maintain the uneven shape may be used in combination. Examples of the fluid include hot air, room temperature air, cold air, and water vapor air. The support preferably has an opening at the bottom of the recess of the support to allow the fluid to pass through. In the present invention, since the web is made difficult to float, the speed of the wind for blowing and suction can be reduced, the force with which the web is pressed against the support is reduced, and an uneven nonwoven fabric with a longer inter-fiber distance and a greater thickness (thickness) can be obtained. However, since the suction hole is easily clogged due to the accumulation of fiber powder, etc., it is preferable that the suction process is not performed. Furthermore, if there is no suction process, blowing without suction will also cause the web to become disturbed. Therefore, if there is no suction process, it is preferable that there is no blowing process. From these viewpoints, it is preferable that the wind speed of suction and blowing is preferably 2 m / s or less, more preferably 1 m / s or less, and even more preferably 0.5 m / s or less, respectively. In addition, it is preferable that the wind speed is 0 m / s or more (no suction or blowing is performed).

[0024] The support peel resistance E1 is set to 1000 cN / m from the viewpoint of more effectively suppressing lifting of the shaped web. 2 More preferably, it is 6000cN / m 2 More preferably, it is equal to or greater than this.

[0025] In addition, the support peel resistance E1 is set to 20000 cN / m 2By setting the thickness to the range below, even if the web has low web strength, the shaped web can be easily peeled off from the support without being damaged, and therefore the uneven shape can be smoothly maintained while peeling off. From this viewpoint, the support peel resistance E1 is 15000cN / m 2 It is preferable that the resistance is less than 10000cN / m 2 It is more preferable to set it as follows:

[0026] In addition, it is preferable that the peel resistance per unit area when peeling the shaped web from the support (support peel resistance E1) is greater than the peel resistance per unit area when peeling the shaped web from the pushing member (hereinafter, pushing member peel resistance E2). This prevents the web from floating when the pushing member is separated from the web after shaping, and makes it easier to leave an uneven shape that conforms to the support.

[0027] From this viewpoint, the ratio (E1 / E2) of the support peeling resistance E1 to the pushing member peeling resistance E2 is preferably 4 or more, more preferably 10 or more, and further preferably 50 or more. Furthermore, there is no particular upper limit to the ratio (E1 / E2); however, there are limitations, including processing costs, to reducing the surface roughness of the pushing member or to providing a wedge-shaped taper so as to reduce the cross-sectional area of ​​the convex portion toward the outer periphery of the pushing member. Therefore, it is preferable to set the ratio to 100,000 or less, more preferably to 1,000 or less, and even more preferably to 100 or less.

[0028] Furthermore, the pushing member peel resistance E2 is 0 cN / m 2 More than 2000cN / m 2 It is preferable that the width of the web is set to be equal to or less than 1 mm. This makes it possible to more effectively prevent the shaped web from being pulled in the direction in which the pushing member is pulled out. As a result, the height of the projections and recesses of the shaped web is more effectively maintained. From the above viewpoint, the pushing member peel resistance E2 is 10 cN / m 2 More preferably, it should be 50 cN / m or more. 2More preferably, it is 100 cN / m or more. 2 More preferably, it is equal to or more than that. In addition, the pushing member peel resistance E2 is 2000cN / m 2 It is preferable that the resistance is less than 1000 cN / m 2 More preferably, it should be 500 cN / m or less. 2 More preferably, it is 280 cN / m or less. 2 It is even more preferable that:

[0029] From the viewpoint of transporting the shaped web along the support even when processing at high speed after shaping, it is preferable that the support peeling resistance E1 is greater than the centrifugal force applied to the web as it is transported. The ratio of the support peeling resistance E1 to the centrifugal force (support peeling resistance E1 / centrifugal force) is preferably 25 to 3000, more preferably 400 to 1500, so that the web 30 does not get caught when peeled off from the support 10. This centrifugal force is calculated by the following formula. Centrifugal force (cN / m 2 )=0.1×W×(v 2 / r) W: Web mass per unit area (g / m 2 ) v: Machining speed (m / s) r: radius (m)

[0030] Since the centrifugal force is proportional to the square of the processing speed v, the faster the processing speed v, the greater the value of the centrifugal force. When the processing speed v is preferably 50 m / min or more, more preferably 80 m / min or more, and even more preferably 120 m / min or more, the effect of the present application becomes more remarkable. A practical processing speed v is preferably 1000 m / min or less, more preferably 600 m / min or less. In addition, the centrifugal force is preferably 10 cN / m 2 More preferably, 100cN / m 2 More preferably, 200cN / m 2 In order to make the centrifugal force lower than the support peel resistance E1, the centrifugal force is set to 20000 cN / m 2It is preferable that the resistance is less than 15000cN / m 2 More preferably, it is 10,000 cN / m or less. 2 It is even more preferable that:

[0031] After shaping, when peeling the web from the support, it is preferable that the value obtained by multiplying the support peel resistance E1 by 0.1 m is lower than the MD strength of the web peeled from the support, because the web is less likely to stretch or tear due to peeling. The difference between the MD strength of the peeled web and the value obtained by multiplying the support peel resistance E1 by 0.1 m (the former - the latter) is preferably 100 cN / m width or more, more preferably 1000 cN / m width or more. In addition, from the viewpoint of not making the web too hard, it is preferably 100,000 cN / m width or less, more preferably 60,000 cN / m width or less. Here, 0.1 m is a value assuming the MD direction support length from the start to the end of peeling the web from the support. The value obtained by multiplying the support peel resistance E1 by 0.1 m corresponds to the support peel resistance per 1 m width. The MD strength (cN / m width) of the web peeled from the support is determined by measuring the maximum tensile strength in the MD direction of the sample using a tensile tester with a chuck distance of 150 mm and a tensile speed of 300 mm / min after peeling from the support, and dividing the value by the CD width of the sample. If the CD width of the sample is 0.5 m or less, the full width is measured, and if it is 0.5 m or more, it is cut to 0.5 m. The chuck width used for the measurement is 50 mm, and the sample is folded in the CD direction for measurement. The measurement environment is a temperature of 23°C ± 2°C and a humidity of 65% RH ± 5% RH. Five samples are measured and their average value is calculated.

[0032] The support peel resistance E1 can be measured by the method described below. The push-in member peel resistance E2 is measured by the same method using push-in members of the same type engaged with each other at the actual engagement amount. However, if push-in members of the same type cannot be engaged with each other (e.g., nets), a support with the same shape and small surface roughness (e.g., a support with a surface roughness Rz of 0.1 μm or less on the side of the convex portion) is used, and the web is left on the push-in member side, and the measurement is performed by the same method. (Method for measuring peel resistance of shaped web) (1) Prepare a target web, and shape the web with the actual meshing amount between the support and the pushing part. When suction of the support, blowing, heating of the support, heating of the pushing part, etc. are performed, they are performed under the conditions for actually manufacturing the nonwoven fabric. (2) The processing speed (roll peripheral speed) is 5 m / min, and the process stops when the web on the support is released from the pushing section and shaped. At this time, if support suction, blowing, support heating, or pushing member heating is being performed, these operations are stopped. (3) Prepare a stainless steel plate 1 mm thick and 30 mm x 30 mm. If the support has a curvature, such as a roll, process the plate so that it conforms to the curvature of the support. Attach a string or the like to the square corners on the back side of the stainless steel plate and connect it to the push-pull gauge. Next, attach a 30 x 30 mm square piece of double-sided adhesive tape (TERAOKA No777 (product name, manufactured by Teraoka Seisakusho Co., Ltd.) or equivalent) to the underside surface of the stainless steel plate, and place a weight on top of the stainless steel plate so that the total weight applied to the push-pull gauge is 50 gf. In this state, zero the push-pull gauge. (4) Immediately after stopping, the following measurements (5) to (7) are carried out quickly. The measurement part should be kept almost horizontal. The measurements are carried out under the temperature conditions in which the nonwoven fabric is actually manufactured. (5) A stainless steel plate is lightly placed on the surface of the web on the support so that the double-sided adhesive tape side is in contact with the surface of the web, and the stainless steel plate is attached to the surface of the web. Next, the web around the plate is cut with small scissors with sharp tips so that the web does not float up from the support. (6) The maximum strength when the web is peeled from the support in the vertical direction at a speed of 300 mm / min is measured using a push-pull gauge. After that, the peeled web mass is measured and subtracted from the measured value to obtain the peel strength (cN / 900 mm 2 ) is required. When the web breaks before peeling from the support, the maximum strength up to the break is measured. When the adhesive tape has a portion directly adhering to the support, such as an open web or a web with a large unevenness in basis weight, the maximum strength is measured after the adhesive portion peels off due to pulling. (7) Measure points at different locations and calculate the average value for an area of ​​1 m 2 The web peel resistance converted to strength per unit (cN / m 2 )

[0033] The above-mentioned support peel resistance E1 means the friction force between the constituent fibers of the web and the support. This frictional force is related as follows: [Friction force] = [Friction coefficient] x [Repulsion force] The "friction coefficient" is the coefficient of friction between the constituent fibers of the web and the convex parts of the support. The "repulsive force" is the elastic force that causes the constituent fibers to spread in the limited space of the concave parts when the web is pressed into the concave parts between the convex parts, and is the force that pushes against the convex parts (arrow F2 in Figure 2).

[0034] This frictional force (i.e., support peeling resistance E1) refers to the force with which the constituent fibers of the web 30 pressed into the recesses 12 of the support 10 are caught on the wall surfaces 11S along the protruding direction of the protrusions 11 of the support 10, as shown in Fig. 2. When this frictional force is equal to or greater than a specific value, the constituent fibers of the pressed web 30 are less likely to slip against the wall surfaces 11S of the protrusions 11. In other words, the frictional force acts as a reaction force F1 when the web 30 is peeled off from the bottoms 11B of the protrusions 11 against the web 30, suppressing the web 30 from floating up to the tops 11T of the protrusions 11.

[0035] The friction coefficient and repulsive force factors are derived from the support side and the web side, respectively. Each of these factors will be explained below.

[0036] First, the factors on the support side that increase the friction coefficient will be explained with reference to the following [1] to [4].

[0037] [1] Percentage (%) of the bottom cross-sectional area of ​​the convex portion 11 to the top cross-sectional area ([top cross-sectional area] / [bottom cross-sectional area]) x 100 As shown in FIG. 3, it is preferable that the cross-sectional area of ​​the convex portion 11 of the support 10 is larger in the circumferential direction at the top 11T than at the bottom 11B. That is, when the cross-sectional area in the circumferential direction at the bottom 11B is the "bottom cross-sectional area" and the cross-sectional area in the circumferential direction at the top 11T is the "top cross-sectional area", it is preferable that the top cross-sectional area is greater than the bottom cross-sectional area. This means that the convex portion 11 is thicker at the top 11T than at the bottom 11B, and it is preferable that the convex portion 11 has a tapered shape that becomes thicker from the bottom 11B to the top 11T. This increases the frictional force between the support 10 and the web 30, that is, increases the support peeling resistance force E1. In addition, the above shape suppresses the force that the web 30 pressed into the recess 12 of the support 10 tries to float toward the top 11T side. The top 11T of the convex portion 11 means the tip of the convex portion 11 in the protruding direction. The circumferential cross-sectional area at the top 11T of the convex portion 11 is measured at the thickest point on the top 11T side. When the tip of the convex portion 11 is a flat surface and this portion is the thickest, the flat surface is regarded as the circumferential cross-section at the top 11T. The bottom 11B of the convex portion 11 means a portion (base portion) of the convex portion 11 adjacent to the bottom 12B of the recess 12. The respective circumferential cross-sectional areas can be measured by observing the periphery of the convex portion 11 and the periphery of the recess 12 with a microscope from two or more directions in the circumferential direction.

[0038] In the above relationship of top cross-sectional area>bottom cross-sectional area, ([top cross-sectional area] / [bottom cross-sectional area])×100 in the protrusions 11 is preferably 101% or more, more preferably 105% or more, and even more preferably 110% or more. In addition, in order to prevent the unevenness of the web 30 from being disturbed when the web 30 is peeled off from the support 10, the ([top cross-sectional area] / [bottom cross-sectional area])×100 of the convex portion 11 is preferably 180% or less, more preferably 150% or less, and even more preferably 120% or less.

[0039] [2] Uneven shape at the corners 11E and near the top 11P of the protrusion 11 As shown in Fig. 4(A), when the wall surface 11S of the protrusion 11 has a corner 11E, it is preferable that a fine uneven shape (hereinafter referred to as a micro uneven shape to distinguish it from the uneven shape of the support 10) is arranged at the corner 11E. Similarly, it is preferable that a micro uneven shape is arranged at the apex vicinity 11P. The corner 11E and the apex vicinity 11P are the parts of the protrusion 11 where the constituent fibers of the web are likely to get caught, and by arranging a micro uneven shape at this part, the friction coefficient can be increased more effectively. Moreover, it is more preferable that such micro unevenness is provided on the corners 11E and the vicinity 11P of the top of the protrusion 11, as well as on the wall surfaces 11S between the corners 11E.

[0040] The micro-irregular shape can be formed by various commonly used methods such as grinding, sandblasting, plating, spraying, and etching. Grinding is particularly preferred because it provides durability and a desirable surface roughness Rz. In these processing methods, the surface is processed while rotating a roll or the like, so that the micro-irregular shape is more easily formed at the corners adjacent to the surfaces parallel to the MD direction than at the corners adjacent to the surfaces parallel to the CD direction of the protrusions 11. It is preferred to form the micro-irregular shape along a surface parallel to the MD direction in order to increase the frictional force at that time when the fibers come into contact with the wall surfaces 11S of the protrusions 11 and their corners 11E as shown in FIG. 6 described later.

[0041] As shown in Figures 4(B) to (D), the micro-convex and concave shapes preferably have the following inclination angles. The inclination angles include an inclination angle on the top side and an inclination angle on the bottom side when viewed along the protruding direction of the convex portions 11. These inclination angles are measured by drawing a straight line approximating the inclined portion, and are referred to as the top-side approximate inclination angle A and the bottom-side approximate inclination angle B, respectively. 4(B) is an example of the micro-convex shape of the convex portion 11 formed by grinding. The top-side approximate inclination angle A is an inclination angle toward the bottom portion 11B side of the convex portion 11. The bottom-side approximate inclination angle B is an inclination angle toward the top portion 11T side of the convex portion 11. 4(C) is another example of the micro-roughness of the convex portion 11 formed by grinding. Both the top side approximate inclination angle A and the bottom side approximate inclination angle B have an inclination angle toward the bottom 11B side of the convex portion 11. The micro-roughness of the convex portion 11 shown in Fig. 4(D) is an example formed by thermal spraying. The top-side approximate inclination angle A is an inclination angle toward the bottom portion 11B side of the convex portion 11. The bottom-side approximate inclination angle B is an inclination angle toward the top portion 11T side of the convex portion 11.

[0042] The top side approximate inclination angle A and bottom side approximate inclination angle B as described above can be measured by the following method.

[0043] (Method of measuring top side approximate inclination angle A and bottom side approximate inclination angle B) First, observation is performed using a microscope at magnifications of 20 to 400 times. The measurement site is the wall or corner of the protrusion 11 that is in contact with the fiber. A straight line is drawn that approximates the inclined portion on the top side and the inclined portion on the bottom side of the micro unevenness with respect to the wall or corner of the protrusion 11. When the micro unevenness is, for example, a mountain shape as shown in Fig. 4(B), a sawtooth shape as shown in Fig. 4(C), or a rounded shape as shown in Fig. 4(D), approximate straight lines L1 and L2 are drawn along the respective inclined surfaces. The angles between the planar direction of the support 10 and the approximate straight line are measured. The micro uneven shapes of the convex portions 11 are measured at 10 different points, and the average values ​​are taken as the top side approximate inclination angle A and the bottom side approximate inclination angle B, respectively.

[0044] In the case of the example in which the micro-convex / concave shape is mountain-shaped as shown in Figure 4(B) and in the example in which it is rounded as shown in Figure 4(D), the values ​​of the apex side approximate inclination angle A toward the bottom 11B side and the bottom side approximate inclination angle B toward the apex 11T side are each considered to be positive. When the micro-convex / concave shape is a sawtooth shape inclined toward the bottom side as shown in Figure 4 (C), the value of the top side approximate inclination angle A toward the bottom 11B side is positive, and the value of the bottom side approximate inclination angle B toward the bottom 11B side is negative. Conversely, when the micro-convex / concave shape is a sawtooth shape inclined toward the apex (not shown), the value of the apex side approximate inclination angle A toward the apex 11T side is negative, and the value of the bottom side approximate inclination angle B toward the apex 11T side is positive.

[0045] The top side approximate inclination angle A and bottom side approximate inclination angle B defined above are preferably in the following ranges. First, the bottom side approximate inclination angle B is preferably -45° or more, more preferably -30° or more, and even more preferably 0° or more, from the viewpoint of preventing the web from getting caught when peeled off from the support 10. The bottom side approximate inclination angle B is preferably 85° or less, more preferably 80° or less, and even more preferably 75° or less, from the viewpoint of increasing friction between the wall portion and the fibers in the floating direction of the web 30 and more effectively suppressing floating of the web 30. Moreover, the apex side approximate inclination angle A is preferably 0° or more, more preferably 50° or more, and even more preferably 60° or more, from the viewpoint of preventing the fibers from getting caught when the web 30 is pressed into the support 10. For example, in the case of a mountain shape, the smaller the angle A, the greater the depth of the peaks and valleys tends to become, creating space for the fibers to enter the valleys, so from the viewpoint of more effectively suppressing floating of the web 30, the apex side approximate inclination angle A is preferably 85° or less, more preferably 80° or less, and even more preferably 75° or less. Furthermore, it is preferable that the top side approximate inclination angle A is larger than the bottom side approximate inclination angle B. In this magnitude relationship, the difference (AB) between the top side approximate inclination angle A and the bottom side approximate inclination angle B is preferably 5° or more, more preferably 10° or more, and even more preferably 15° or more, from the viewpoint of preventing the fibers from getting caught when the web 30 is pressed into the support 10. Moreover, the difference (AB) is preferably 90° or less, more preferably 60° or less, and even more preferably 30° or less, from the viewpoint of more effectively suppressing the lifting of the web.

[0046] [3] Surface roughness Rz of the wall surface 11S of the protruding portion 11 The high surface roughness Rz of the wall surfaces 11S of the projections 11 increases the coefficient of friction, making it easier for the constituent fibers of the web to become caught, and thus making it possible to more effectively suppress lifting of the web. From this viewpoint, the surface roughness Rz of at least a part of the wall surface 11S of the protrusion 11 is preferably equal to or greater than 1 μm, more preferably equal to or greater than 5 μm, and even more preferably equal to or greater than 15 μm. Further, the surface roughness Rz of at least a part of the wall surface 11S of the protrusion 11 is preferably 75 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less, from the viewpoint of preventing the web from getting caught when peeled off the support 10. The above surface roughness Rz is preferably in an area of ​​20% or more of the area of ​​the wall surface 11S of the protrusion 11, more preferably in an area of ​​30% or more, and further preferably in an area of ​​40% or more. The above surface roughness Rz can be formed by using various methods applied to this type of support 10, such as grinding, sandblasting, plating, spraying, etching, etc. Grinding is particularly preferred in that it provides durability and a preferred micro-irregular shape.

[0047] (Method of measuring surface roughness) The surface roughness (maximum height) Rz of the support protrusion wall is measured in accordance with ISO4287-1997. The measurement conditions are λc 0.8 mm, λs 2.5 mm, section 5, GAUSS filter, curve R, speed 0.5 mm / s, measurement range 4.8 mm, stylus tip angle 90 degrees, tip radius 2 μm, and measurement force 4 mN. As the measuring instrument, for example, SJ210 (product name) manufactured by Mitutoyo Corporation can be used. The measurement is performed in the direction in which the web 30 at the protruding portion is peeled off. The roughness of the wall surface 11S of each of the different projections 11 is measured at three points, and the average value is taken as the surface roughness Rz.

[0048] [4] Amount of engagement D between the support 10 and the pushing member 20 As shown in Fig. 5, the meshing amount D means the depth to which the pushing portion 21 of the pushing member 20 penetrates into the recesses 12 between the protrusions 11, 11 of the support 10. A large meshing amount D means that the web 30 is pushed deeper into the recesses 12, and the contact area with the wall surfaces 11S of the protrusions 11 increases. This increases the frictional force between the pushed-in web 30 and the protrusions 11, i.e., the support peel resistance E1. Furthermore, by increasing the meshing amount D, the height difference between the protrusions and recesses of the shaped web 30 can be made larger, and a fluffy, cushioned uneven nonwoven fabric can be formed. In this respect, the amount of meshing D is preferably equal to or greater than 0.5 mm, more preferably equal to or greater than 1 mm, and further preferably equal to or greater than 2 mm. Moreover, from the viewpoint of suppressing holes and deterioration of cushioning properties due to uneven texture in the uneven nonwoven fabric, the meshing amount D is preferably 15 mm or less, more preferably 10 mm or less, and even more preferably 8 mm or less.

[0049] Next, factors on the support side that increase the repulsive force will be explained with reference to the following [1] and [2].

[0050] [1] Gap distance W1 between convex parts 11, 11 5, by reducing the gap distance W1 between the protrusions 11, 11, the web 30 pressed into the recesses 12 by the pressing section 21 is curved at a sharper angle, and the radius of curvature of the curved web 30 is reduced. This increases the repulsive force of the web 30 against the protrusions 11, and increases the frictional force between the support 10 and the web 30, i.e., the support peel resistance force E1. In particular, the radius of curvature R2 of the curved web 30 on the top 11T side of the protrusion 11 becomes smaller than the radius of curvature R1 of the curved web 30 on the bottom 11B side of the protrusion 11. From this viewpoint, the gap distance W1 between the protruding portions 11, 11 of the support is preferably equal to or less than 10 mm, more preferably equal to or less than 5 mm, and further preferably equal to or less than 3 mm. In addition, the gap distance W1 is preferably 0.5 mm or more, more preferably 1 mm or more, and even more preferably 1.5 mm or more, from the viewpoint of keeping the uneven pitch in the uneven nonwoven fabric within an appropriate range and maintaining the strength when making the convex portion of the pushing member 20 thin. In addition, when the protrusions 11 have a shape in which the circumferential cross-sectional area is larger at the top 11T than at the bottom 11B as described above, the gap distance W1 between the protrusions 11, 11 is preferably 1 mm or more and 8 mm or less, and more preferably 1.5 mm or more and 4 mm or less, from the viewpoint of making it more difficult for the web to float due to centrifugal force, because the frictional force against the repulsive force due to the gap distance W1 is increased by the protrusions 11 having such a tapered shape. When the protrusions 11 have a tapered shape, etc., the gap distance W1 is the average interval distance between the protrusions 11, 11 in the range from the top 11T to the meshing amount D.

[0051] [2] Projected cross-sectional area ratio in the CD direction where the convex portion 11 of the support 10 and the web 30 come into contact when the support 10 and the pushing member 20 are engaged with each other The above-mentioned projected cross-sectional area ratio in the CD direction means the area of ​​the portion 11M where the web 30 overlaps with the protrusion 11 (mainly the wall surface 11S) when observing in the CD direction the web 30 pushed in by the meshing of the support 10 and the pushing member 20. In other words, it can also be said to be the area where the pushing portion 21 of the pushing member 20, corresponding to the meshing amount D, overlaps with the protrusion 11 of the support 10 when projected. The observation in the CD direction is based on the premise that the pressing by the pressing member is performed along the MD direction against the recesses 12 that extend continuously in the MD direction as shown in Fig. 6(A). In this case, as shown in Fig. 6(A), Fig. 7 and Fig. 8, when the protrusions 11 of the support 10 are arranged in a grid pattern at equal intervals in the MD and CD directions and pressing is performed along the MD direction, the force pressing the web 30 spreads to the recesses 12 between the protrusions 11 in the row of adjacent protrusions 11 aligned in the MD direction. Weak pressing of the web 30 occurs along the CD direction at the positions of the recesses 12. As a result, in the obtained uneven nonwoven fabric, in addition to the ridges along the MD direction, intermediate ridges that connect the ridges in the CD direction are formed, forming a ridge-groove structure in which the vertical and horizontal ridges are arranged in a lattice pattern.

[0052] This projected cross-sectional area ratio in the CD direction can be calculated using the following formula. Projected cross-sectional area ratio = (average opposing length per pitch between convex parts × meshing amount of opposing parts) / (1 pitch length × meshing amount of opposing parts) × 100 Here, "one pitch length" means the pitch length of the convex portions 11 in the row of the convex portions 11, 11 aligned in the MD direction, and is shown as one pitch length 8W in FIG. 6(B). "Amount of meshing of opposing portions" means the amount of meshing between the convex portion 11 and the push-in portion 21, and is shown as meshing amount 8D in FIG. 6(B). Also, "average length of opposition between convex portions per pitch" means the length in the MD direction opposing each other when the push-in portion 21 is projected in the CD direction relative to the convex portion 11 within the aforementioned one pitch length 8W, and is shown as the average opposing length 11W in FIG. 6(B). The average length 11W means the average length in the MD direction when projected from the top of the convex portion 11 over the meshing amount 8D (11D). The denominator in the above formula (one pitch length × meshing amount of each part) is shown by the symbol 8M in Fig. 6(B), and the numerator (average opposing length per pitch between convex parts × meshing amount of opposing parts) is shown by the symbol 11M in Fig. 6(B). In other words, the above projected cross-sectional area ratio is 11M / 8M.

[0053] The larger the projected cross-sectional area ratio in the CD direction defined above, the larger the contact area between the web 30 and the support 10. This increases the repulsive force of the web 30 against the protrusions 11, and increases the frictional force between the support 10 and the web 30, i.e., the peel resistance. From this viewpoint, the above-mentioned projected cross-sectional area ratio in the CD direction is preferably equal to or greater than 30%, more preferably equal to or greater than 35%, and even more preferably equal to or greater than 40%. In addition, the above-mentioned projected cross-sectional area ratio in the CD direction is preferably 100% or less, more preferably 80% or less, and even more preferably 60% or less, from the viewpoint of forming intermediate ridge portions extending in the CD direction between the convex portions 11, 11 to increase the resistance of the uneven nonwoven fabric to compression collapse.

[0054] Next, factors on the web side that increase the support peel resistance E1 will be explained below.

[0055] [1] Fiber oil (fiber treatment agent) contained in the web 30 By using a textile oil having a high friction coefficient contained in the web 30, the friction coefficient of the web 30 with respect to the substrate 10 increases, and the frictional force between the substrate 10 and the web 30, that is, the peel resistance, increases. 9, it is particularly preferable to have the web 30 have a multi-layer structure, using a textile oil with a high friction coefficient for the first layer 31 on the bottom 11B side of the protrusions 11 on the support 10, and using a textile oil with a low friction coefficient for the second layer 32 on the top 11T side of the protrusions 11. From the above viewpoints, the amount of textile oil relative to the fiber weight is preferably from 0.2 to 0.6% by mass, more preferably from 0.3 to 0.5% by mass, thereby reducing peeling of the web 30 from the support 10 and reducing accumulation of textile oil due to adhesion to the support 10, and thus improving the performance. This increases the frictional force between the support 10 and the web 30, i.e., the peel resistance, and at the same time makes it difficult for the uneven shape of the web 30 to collapse when the web 30 is peeled off from the pushing member 20. To confirm this, a nonwoven fabric is made by subjecting a flat web 30 to air-through heat treatment on a conveyor net without forming it into an uneven shape, and using each fiber for the first and second layers, one in which the first layer is the net surface and one in which the second layer is the net surface are each prepared, and these are used to measure the average friction coefficient. Furthermore, the textile oil accumulates on the support 10 as the production process progresses, so the peel resistance gradually increases. In order to maintain an appropriate peel resistance at the start of the production process, it is preferable to set the average coefficient of friction (MIU) to 0.2 or more and 0.33 or less.

[0056] (Method of measuring the mean coefficient of friction (MIU)) The average coefficient of friction (MIU) can be measured by the following method. That is, an automatic surface tester (KES FB4-AUTO-A manufactured by Kato Tech Co., Ltd.) is used, and a gauge head made of a steel piano wire with a diameter of 0.5 mm is used to measure the average coefficient of friction (MIU) of 1 cm2. 2 , load 50gf / cm 2 The frictional force is measured when the sheet is moved back and forth over a length of 30 mm at a speed of 1 mm / s. The analysis distance is set to 20 mm by cutting 5 mm of data at both ends. The surface friction coefficient is calculated as MIU. The measurement surface is set so that the probe faces the target surface, and the measurement directions are the MD and CD directions, and the measured values ​​are averaged. The initial sample tension is 10 cN / cm. Each measurement value is calculated by measuring five points on the sheet and averaging the values.

[0057] [2] Multi-layer structure using constituent fibers with different fiber diameters in the web 30 As shown in FIG. 9, the web 30 has a multi-layer structure, and it is preferable to thicken the fiber diameter of the fibers constituting the second layer 32 on the top 11T side of the protrusions 11 in the support 10 (the R2 side where the curvature radius of the pressed web 30 is small). In this case, it is preferable to thin the fiber diameter of the fibers constituting the first layer 31 on the bottom 11B side of the protrusions 11 in the support 10 (the R1 side where the curvature radius of the pressed web 30 is large). This increases the repulsive force of the web 30 pressed into the recess 12 and sandwiched between the protrusions 11, 11 against the protrusions 11, and increases the frictional force between the support 10 and the web 30, i.e., the peel resistance. From the above viewpoint, it is preferable that the ratio of the average fiber diameter on the pressing member 20 side to the average fiber diameter on the support 10 side (latter / former) is 1.1 or more, more preferably 1.5 or more, and preferably 3.5 or less, more preferably 3.0 or less, in order to obtain a nonwoven fabric with less uneven texture.

[0058] (Method of measuring average fiber diameter) The average fiber diameter can be measured by the following method. That is, the nonwoven fabric is observed from the cross section in the thickness direction with a scanning electron microscope (SEM). The fiber diameter that is considered to be approximately average within the observation range is determined as the representative fiber diameter. The observation magnification differs depending on the fiber diameter, and observation is performed at a magnification in the range of ±50% of the observation magnification (times) = 6000 / representative fiber diameter (μm). For example, when the representative fiber diameter is 20 μm, observation is performed at a magnification of 150 times or more and 450 times or less. An image is taken by focusing on the fibers on the upper side, that is, the side irradiated with the electron beam. When the fiber consists of two or more fiber layers, the fiber diameter of each fiber layer is measured. For one image, the fiber thickness of randomly selected different fibers, that is, the width in the direction perpendicular to the longitudinal direction of the fiber, is measured at 10 points in the part excluding the fusion part at the fiber intersection and the end of the fiber, and the average value is taken as the fiber diameter. The values ​​measured in the same manner for five different samples are averaged to determine the average fiber diameter. If the fiber cross section is not circular, ten fibers that are oriented perpendicular to the SEM image are selected by observing the cross section of the nonwoven fabric in the thickness direction, and the cross-sectional area is calculated from their cross-sectional shape. The fiber diameter is calculated from the diameter of the cross-sectional area when it is assumed to be circular.

[0059] [3] Thickness of web 30 Web thickness before forming (0.5g / cm 2 It is preferable to thicken the thickness (under load) of the web 30. This increases the repulsive force of the web 30 when the pushing portion 21 engages between the protrusions 11, 11 and pushes the web 30 in, thereby increasing the frictional force, i.e., the support peeling resistance force E1. From the above viewpoints, the thickness of the web 30 is preferably 0.5 mm or more, and more preferably 1 mm or more. Also, from the viewpoint of enabling smooth insertion into the gaps between the convex portions of the support 10, the thickness of the web 30 is preferably 5 mm or less, and more preferably 4 mm or less.

[0060] In the method for producing a nonwoven fabric of the present invention, by satisfying the above-mentioned requirements, the web is prevented from floating off the support, and the uneven shape is less likely to be disturbed from the web shaping step to the fiber fusion or fiber compression step. This makes it possible to suitably produce a nonwoven fabric with an excellent uneven shape. Also, as opposed to appropriately increasing the peel resistance between the support 10 and the web 30, it is preferable that the pushing-in member 20 has a reduced peel resistance with the web 30. That is, it is preferable that the pushing-in member 20 has a configuration opposite to the above-mentioned configuration of the support 10. This is preferable because when the pushing-in member 20 is pulled out from the web 30 pushed into the recess 12 of the support 10, the web 30 tends to remain favorably on the top part 11T side of the support 10.

[0061] Methods for reducing the peel resistance force E2 of the push-in member 20 will be described with reference to the following items (1) to (5).

[0062] [1] Percentage (%) of the bottom cross-sectional area of ​​the pushing portion 21 to the top cross-sectional area ([top cross-sectional area] / [bottom cross-sectional area]) x 100 As shown in FIG. 10, the pushing portion 21 of the pushing member 20 preferably has a smaller circumferential cross-sectional area at the top 21T than at the bottom 21B. That is, when the circumferential cross-sectional area at the bottom 21B is the "bottom cross-sectional area" and the circumferential cross-sectional area at the top 21T is the "top cross-sectional area", the relationship of the top cross-sectional area < the bottom cross-sectional area is preferable. This means that the pushing portion 21 is narrower at the top 21T than at the bottom 21B, and it is preferable that the pushing portion 21 has a tapered shape that narrows from the bottom 21B to the top 21T. This reduces the frictional force between the pushing member 20 and the web 30, that is, the pushing member peeling resistance force E2 is reduced. In the above relationship of the top cross-sectional area < the bottom cross-sectional area, ([top cross-sectional area] / [bottom cross-sectional area])×100 at the pushing portion 21 is preferably 99% or less, more preferably 95% or less, and even more preferably 90% or less. In addition, from the viewpoint of ensuring the strength of the pushing portion 21 of the pushing member 20, ([top cross-sectional area] / [bottom cross-sectional area])×100 in the pushing portion 21 is preferably 10% or more, more preferably 20% or more, and even more preferably 30% or more.

[0063] [2] Shape of the corners 21E and the top vicinity 21P of the push-in portion 21 When the wall surface 21S of the pushing portion 21 of the pushing member 20 has a corner 21E, it is preferable that the corner 21E does not have the above-mentioned micro uneven shape. Similarly, it is preferable that the apex vicinity 21P does not have a micro convex shape. The corner 21E and the apex vicinity 21P are parts of the pushing portion 21 where the constituent fibers of the web are likely to get caught, and by making these parts smooth, the friction coefficient can be reduced more effectively.

[0064] [3] Surface roughness Rz of the wall surface 21S of the pressing section 21 The small surface roughness Rz of the wall surface 21S of the pushing portion 21 of the pushing member 20 reduces the coefficient of friction, making it difficult for the constituent fibers of the web to get caught, and more effectively suppressing the web from floating. From this viewpoint, the surface roughness Rz of at least a part of the wall surface 21S of the push-in portion 21 is preferably equal to or less than 1 μm, more preferably equal to or less than 0.5 μm, and even more preferably equal to or less than 0.1 μm. From the viewpoint of reducing the time required for polishing, the surface roughness Rz of at least a part of the wall surface 21S of the pressing portion 21 is preferably 0.01 μm or more, more preferably 0.03 μm or more, and even more preferably 0.05 μm or more. From the viewpoint of the above, it is preferable that the surface roughness Rz of the wall surface 21S of the pressing portion 21 of the pressing member 20 is smaller than the surface roughness Rz of the wall surface 11 of the protrusion 11 of the support 10. The ratio of the former / latter is preferably 2 or more and 100 or less, and more preferably 10 or more and 70 or less. The above surface roughness Rz is preferably in an area of ​​20% or more of the area of ​​wall surface 21S of push-in portion 21, more preferably in an area of ​​30% or more, and even more preferably in an area of ​​40% or more. The surface roughness Rz can be formed by using various methods such as polishing, plating, vapor deposition, etc., which are applied to this type of indentation member 20. The measurement can be performed by the same method as for the protrusions 11.

[0065] [4] Gap distance W2 between push-in portions 21, 21 By increasing the gap distance W2 between the push-in portions 21, 21 of the push-in member 20, the web 30 pushed into the recesses 12 by the push-in portions 21 curves more gently, and the radius of curvature (R1, R2) of the curved web 30 increases. This reduces the pressing pressure of the web 30 against the push-in portions 21, and the frictional force between the push-in member 20 and the web 30, i.e., the peel resistance force E2, decreases. At this time, the peel resistance force E1 on the support 10 side also decreases, but since the pressing pressure of the web 30 against the push-in member 20 decreases more than the decrease in the repulsive force of the web 30 against the support 10, the rate of decrease in the peel resistance force E2 is relatively greater. From this viewpoint, the gap distance W2 between the push-in portions 21, 21 of the push-in member 20 is preferably equal to or greater than 1 mm, more preferably equal to or greater than 2 mm, and further preferably equal to or greater than 3 mm. Moreover, from the viewpoint of setting the concave-convex pitch in the concave-convex nonwoven fabric in an appropriate range, the gap distance W2 is preferably 14 mm or less, more preferably 10 mm or less, and even more preferably 7 mm or less. When the push-in portion 21 has a shape in which the circumferential cross-sectional area is smaller at the top 21T than at the bottom 21B as described above, the gap distance W2 between the push-in portions 21, 21 is preferably 2 mm or more and 8 mm or less, and more preferably 3 mm or more and 6 mm or less, from the viewpoint of more effectively suppressing the lifting of the web, since the frictional force against the repulsive force due to the gap distance W2 is further reduced by the push-in portion 21 having such a tapered shape, when the push-in portion 21 has a tapered shape or the like, the gap distance W2 is the average interval distance between the push-in portions 21, 21 in the range from the top 21T to the meshing amount D.

[0066] [5] Projected cross-sectional area ratio in the CD direction where the pushing portion 21 of the pushing member 20 contacts the web 30 when the support 10 and the pushing member 20 are engaged with each other The above-mentioned projected cross-sectional area ratio in the CD direction is determined by the same method as that for the projected cross-sectional area ratio in the CD direction where the protrusions 11 of the support 10 and the web 30 are in contact with each other.

[0067] In the manufacturing method of the uneven nonwoven fabric of the present invention, the support and pushing member can be of various shapes that can realize the above-mentioned requirements and satisfactorily form the intended uneven shape of the uneven nonwoven fabric. For example, the support 10 shown in Figs. 7 and 8 can be preferably used. In this support 10, the convex portions 11 are arranged in a square shape, and the concave portions 12 are arranged in a lattice shape. A concave-convex nonwoven fabric having a ridge-and-groove structure in which vertical and horizontal ridges are arranged in a lattice shape can be formed along the convex portions 11 and the concave portions 12 between them. In addition, in the support 10 shown in Figs. 7 and 8, the convex portions 11 are columnar with corners 1E, and the wall surfaces 11S are vertically erected relative to the substrate 13. In the concave-convex nonwoven fabric obtained by this, the constituent fibers tend to be aligned in the vertical direction, and the height difference of the concave-convex shape becomes large. As a result, the concave-convex nonwoven fabric is bulky and has high cushioning properties that are excellent in both compressibility and thickness recovery against pressure, and has shape retention that is not easily sagging even when pressed. Even if the cross-sectional area in the circumferential direction is larger at the top 11T than at the bottom 11B, the intersection angle θ between the wall surface 11S at the bottom 11B and the substrate 13 is preferably in the range of 75° to 89°. In addition, when the support 10 is in the form of a drum roll, the angle between the tangent J at the intersection of the protrusion 11 and the substrate 13 and the protrusion 11 is the intersection angle θ. The pressing member 20 may be provided with a lattice-shaped pressing portion 21 corresponding to the lattice-shaped recesses 12 of the support 10 shown in Figs. 7 and 8, or may be provided with a pressing portion 21 along the MD direction of the lattice-shaped recesses 12 of the support 10. Alternatively, the pressing portion 21 may be provided along the CD direction of the recesses 12 of the support 10. An example of a pressing portion 21 provided along the MD direction of the recesses 12 of the support 10 is a ring roll in which a plurality of disk-shaped rings are gathered in the CD direction and bundled by passing them through a roll shaft. Alternatively, instead of the disk-shaped rings, a ring roll using a gear roll having further unevenness on the circumference of the ring may be used. Furthermore, when the length ratio of the convex portion 11 of the pressing portion 21 at the position of half the meshing amount D is 50% or less in the MD or CD direction, the "intermittent contact" becomes more prominent, which is preferable. In the uneven nonwoven fabric obtained by this, in addition to the ridges along the MD or CD direction, intermediate ridges connecting the ridges in the CD or MD direction are formed, and a ridge-groove structure in which vertical and horizontal ridges are arranged in a lattice shape is formed. For example, when a ring roll formed by bundling multiple gear rolls as the pressing portion 21 by passing them through a roll shaft is used as the pressing member 20, the ratio of the circumferential length in the MD direction where the teeth of the gear roll are present at the position of half the meshing amount D may be less than 50%.

[0068] Furthermore, in the method for producing the uneven nonwoven fabric of the present invention, the uneven nonwoven fabric may consist of only the uneven nonwoven fabric obtained by carrying out the shaping treatment, or may be a laminate of the uneven nonwoven fabric and another sheet. The laminate of the embossed nonwoven fabric and another sheet can be obtained by various manufacturing methods commonly used for this type of article, for example, a manufacturing method using a manufacturing apparatus 200 shown in FIG.

[0069] The manufacturing apparatus 200 shown in Fig. 11 includes a web supply section 102 that supplies a heat-fusible web 300 using fibers that are raw materials for nonwoven fabric, a conveyor belt 104 that transports the web 300 supplied from the web supply section 102, and a nip roller 106 that pressurizes the heat-fusible web 300 transported by the conveyor belt 104. Downstream of the web supply section 102, the manufacturing apparatus 200 includes a pair of rolls (support roll (support) 10 and push roll (pushing member) 20) that perform shaping processing on the heat-fusible web 300 to form a shaped web 301, a point bonding means 130 that fuses part or all of the fibers at the bottom of the recesses of the shaped web 301 pulled by the support roll 10, and a cooling roll 114 that cools the fused portion (embossed portion) fused by the point bonding means 130. In addition, a mechanism for supplying a fiber layer 140 to be laminated as a lower layer of the shaped web 301 is provided between the support roll 10 and the point bonding means 130. The fiber layer 140 may be a heat-sealable web or a nonwoven fabric. When the fiber layer 140 is a heat-sealable web, the fibers of the fiber layer 140 penetrate into the interior of the convex portions formed on the shaped web 301, producing a two-layered, solid-structured, uneven nonwoven fabric. When the fiber layer 140 is a nonwoven fabric, a two-layered, closed-hollow-structured, uneven nonwoven fabric is produced. Further, downstream of the cooling roll 114, there is a second belt conveyor 117 and a heat flow section 118 where a heated fluid is sprayed onto the embossed web 302 that has been subjected to the uneven shaping treatment and embossing treatment to fuse the fiber intersections, i.e., to form a nonwoven fabric.

[0070] The web supply unit 102, the conveyor belt 104, and the nip roller 106 are configured to supply and transport the heat-fusible web 300 using fibers toward the support roll 10 and the push-in roll 20. The cooling roll 114 is configured to transport the embossed web 302, on which the embossed portion 3 is formed by the point joining means 130, toward the downstream side while cooling it. Although the conveyor belt 104, the nip roller 106, and the cooling roll 114 may not be used as appropriate, it is preferable to provide them for stable production. As the web supply unit 102, the conveyor belt 104, the nip roller 106, and the cooling roll 114, various configurations that are usually used can be adopted.

[0071] In the manufacturing apparatus 200 having the above configuration, first, the heat-fusible web 300, which is the processing raw material, is supplied from the web supply unit 102 onto the conveyor belt 104, and the heat-fusible web 300 is conveyed between the support roll 10 and the push-in roll 20 by the conveyor belt 104 while being pressed by the nip roller 106. Here, the nip roller 106 does not firmly bond the fibers, but presses the fibers together to such an extent that the heat-fusible web 300 can be conveyed. Most of the pressed parts at this time tend to peel off due to the tensile tension when the support roll 10 and the push-in roll 20 are engaged. In this way, the peeling reduces the pressed parts, which increases the freedom of the fibers and provides an excellent texture, and is therefore preferable. In addition, even if a part of the pressed parts remains, the pressed parts are not fused parts, so there is almost no deterioration in texture due to snagging.

[0072] In addition, in the manufacturing apparatus 200, the web supply unit 102 is shown as supplying a single-layer heat-sealable web 300, but is not limited thereto. For example, the web supply unit 102 may include two or more devices so as to be able to supply a heat-sealable web 300 having a thickness of two or more layers. When the heat-sealable web 300 is supplied onto the conveyor belt 104 as a laminate of two or more layers, in the manufacturing apparatus 200, the support roll 10 and the push-in roll 20 impart unevenness to the entire laminate.

[0073] After the heat-sealable web 300 reaches the meshing portion of the support roll 10 and the push-in roll 20, an uneven shape is formed in the heat-sealable web 300 by the meshing with the support roll 10 and the push-in roll 20, and a shaped web 301 is formed (step (I)). The shaped web 301 is subjected to an embossing heat fusion process or an embossing pressure bonding process (step (II)) simultaneously with shaping by the above-mentioned support roll 10 and the push-in roll 20, or preferably after shaping. When the embossing heat fusion process or the embossing pressure bonding process is performed after shaping, the shaped shaped web 301 is brought into close contact with the peripheral surface of the support roll 10 by the support roll 10, and is transported to the position of the point bonding means 130 by the rotation of the support roll 10 while maintaining the state in which the uneven shape is formed. By sandwiching the point bonding means 130 and the convex or concave portion of the support roll 10, the fibers at the bottom of the concave portion of the shaped web 301 are embossed (pressure fusion or pressure bonding). At this time, the fiber layer 140 to be laminated as the lower layer is supplied, and the concave portion of the shaped web 301 and the fiber layer 140 are embossed together. As a result, the embossed portion 3 is formed in a predetermined pattern. Thereafter, the embossed web 302 on which the embossed portions 3 have been formed is delivered to a cooling roll 114 where it is cooled, and is then transported by a second conveyor belt 117 downstream thereof, where the fiber intersections are fused at the heat flow portion 118. The convex portions of the obtained nonwoven fabric are formed by fused portions of the fibers at the intertwined portions of the fibers, and the concave portions of the nonwoven fabric are formed by embossed portions and fused portions of the fibers at the intertwined portions of the fibers (step (III)). This produces a laminated nonwoven fabric 100 having an uneven surface, which is composed of an upper layer having an uneven surface and a lower layer having a flat back surface. When the fiber layer 140 to be laminated as a lower layer of the shaped web 301 is not supplied between the support roll 10 and the point joining means 130, a rugged nonwoven fabric is produced only from the shaped web 301.

[0074] As the point bonding means 130 used in the embossing heat fusion process or the embossing pressure bonding process, a heated heat roll (calendar roll) device, a pressure bonding device, or an ultrasonic device that heats by ultrasonic waves can be used. Examples of the heat roll device include those with a flat peripheral surface and those with a convex structure on the peripheral surface. Examples of the ultrasonic device include those with a flat peripheral surface (arc-shaped or planar) and those with a convex structure on the peripheral surface. Using such a device, the fibers at the bottom of the recesses of the interlocking shaped web can be heated at points to perform embossing heat fusion. Further, examples of the bonding device include devices having a roll peripheral shape similar to that of the above-mentioned heat roll device and ultrasonic device (a convex structure, a roll peripheral shape having a convex structure, a flat roll peripheral shape, etc.), and applying pressure at points to the fibers at the bottom of the recesses of the interlocking shaped web to emboss and bond them.

[0075] The embossed portion formed by the embossing heat fusion process or the embossing pressure bonding process means a portion where the fiber layer at the bottom is compressed by the embossing process and the fibers are pressure fused or pressure bonded. In the embossed portion, the fibers are denser than the surrounding area. The "fiber-fiber fusion portion" means a portion where the fibers are fused without being crushed, unlike the "pressure fusion" or "press bonded" portions described below.

[0076] "Pressure fusion" means that the resin of at least one fiber at the joining interface between the fibers is melted by pressure and heat (due to intermolecular friction or self-heating due to compression, or due to external heating) and joined to the other fiber (this pressure fusion process is also called embossed heat fusion). In pressure fusion, pressure is applied to the fibers from the outside by at least clamping. Since the melting point of some resins that make up the fibers decreases due to pressure, the heating temperature (surface temperature of the processing roll, etc.) may be lower than the melting point of the resin under no load. The fact that the nonwoven fabric is pressure-fused can be confirmed by observing the cross section of the nonwoven fabric with a scanning electron microscope, where the fibers are crushed and deformed compared to other parts, and at least one of the resins constituting the fibers is melted and does not have a fibrous form. Regarding the degree of crushing and deformation of the fibers, it is preferable that the average flattening (ratio of long side / short side) of the fiber cross section (cross section perpendicular to the longitudinal direction of the fiber) is 20% or more higher in at least a part of the cross section of the boundary between the embossed part and the fiber (also called the embossed boundary) compared to the non-embossed part. The increase in the average flattening (%) is calculated as [(average flattening of the embossed boundary - average flattening of the non-embossed part) / average flattening of the non-embossed part] x 100. When the outer periphery of the fiber cross section is not circular or elliptical, the long side and short side are calculated by approximating the outer periphery of the fiber to an elliptical shape with the same cross-sectional area.

[0077] "Compression bonding" means that one fiber adheres to another fiber without the resin melting due to heat or pressure (this compression bonding process is also called embossed compression bonding). In compression bonding, pressure is applied from the outside by at least clamping. The force that causes the fibers to adhere to each other (also called adhesion force) needs to be strong enough to allow the sheet to be transported. The fact that the fibers are bonded can be confirmed by observing the cross section of the nonwoven fabric with a scanning electron microscope, where the fibers are crushed and deformed compared to other parts, and the contact length at the fiber cross section at the contact point between the fibers is longer than at the non-bonded part. The degree to which the fibers are crushed and deformed is the same as in pressure fusion. The fact that the fibers are not melted can be confirmed by being able to distinguish the boundary between the outer surface of the fiber and the outer surface of the other fiber at the bonded part. In addition, it is preferable that the contact length per contact point between the fibers is increased by 10% or more on average compared to the non-bonded part. The increase in contact length (%) can be calculated as [(contact length of the fiber outer periphery at the bonded part - contact length at the non-bonded part) / contact length at the non-bonded part] x 100. To observe the cross section of the contact point between the fibers, the sample is embedded in resin (solidified with a resin such as epoxy resin or acrylic resin that does not easily swell or deform the constituent fibers), and then a cross section is formed with a sharp blade. In the embossed portion, for example, the fibers are aligned along the planar direction of the nonwoven fabric and tend to be crushed and flattened or film-like. The embossed portion has a higher fiber density than other portions. Such an embossed portion preferably has a flat plate shape with a compressed thickness.

[0078] When the web 30 is formed into an uneven shape by meshing with the support roll (support) 10 and the push-in roll (pushing member) 20, it is preferable that the fibers are not constrained (not made into a nonwoven fabric) by thermal fusion, mechanical entanglement, or chemical bonding, because this increases the degree of freedom of the fibers and makes it less likely that the fibers will stretch, develop holes, or break. This is particularly noticeable when the meshing amount D is as high as 3.5 mm or more and 10 mm or less.

[0079] When there are not one but multiple pairs of rolls (pairs of support and pushing member) having intermeshing concave and convex shapes, the shaping step involves multiple rounds of concave and convex shaping treatment. The form of the process can take various forms that can successfully give the web an uneven shape. The roll that holds the web is the support roll (support), and the roll that does not hold the web is the pushing roll (pushing member). For example, when there are three intermeshing rolls (first roll, second roll, and third roll), the first roll and the second roll form a pair, and the second roll and the third roll form a pair and intermesh with each other. At this time, the second roll intermeshes with the third roll at a peripheral surface position different from the position where it intermeshes with the first roll. In this way, the intermeshing is continued in a relay format, and the uneven shaping process is performed multiple times. The second roll serves as a support roll for the first roll, and as a push roll for the third roll. When there are four or more intermeshing rolls, the intermeshing may be performed in a relay format in the same manner. Alternatively, multiple pairs of rolls may be arranged without sharing the rolls, and each pair may be independently intermeshed with each other. Furthermore, the first roll may be used as a main roll (support roll), and multiple rolls (pushing rolls such as the second roll and the third roll) may be arranged on the peripheral surface of the first roll, so that the multiple rolls can be arranged to intermesh with the first roll. This makes it difficult for the pushed-in fibers to return, and makes it possible to prevent the interlocking shaped web having the irregularities shaped thereon from being peeled off from the roll by centrifugal force.

[0080] The method for producing a nonwoven fabric with projections and recesses of the present invention exerts a more remarkable effect when used in the production method and production apparatus described below.

[0081] A method for producing a nonwoven fabric for absorbent articles having a plurality of convex portions and concave portions located between the convex portions, the method comprising the steps of: forming an interlocking shaped web by subjecting a web made of fibers, preferably a heat-fusible web, to an uneven shaping process using one or more pairs of a support and a pushing member having a plurality of projections and depressions and having an uneven shape that can interlock with each other; Simultaneously with or preferably after the shaping step, an embossing heat fusion step or preferably an embossing pressure bonding step is performed in which some or all of the fibers at the bottom of the recesses of the interlocking shaped web are bonded at some or all of the positions of the plurality of protrusions or some or all of the positions of the plurality of recesses; a heat fusion step of forming fused portions at fiber intersections on the web embossed by the embossing heat fusion step or the embossing pressure bonding step, using a heated fluid, preferably hot air; The nonwoven fabric manufacturing method includes the steps of:

[0082] The nonwoven fabric manufacturing method further includes a web supplying section for supplying a heat-fusible web using fibers that are raw materials for the nonwoven fabric, and a conveyor belt for transporting the heat-fusible web supplied from the web supplying section, An example of a nonwoven fabric manufacturing apparatus includes a pushing member and a support downstream of the conveyor belt that apply shaping processing to the heat-fusible web to form an interlocking shaped web, a point joining means that fuses or preferably presses some or all of the fibers at the bottom of the recesses of the interlocking shaped web pulled by the support, and a cooling roll that cools the embossed web having an embossed portion formed by the fusion, and a second belt conveyor downstream of the cooling roll, and a heat flow section that sprays a heated fluid onto the embossed web to fuse fiber intersections.

[0083] Further, there is mentioned a method for producing a nonwoven fabric, which includes a pressing step in which a heat-fusible fiber web is placed on a support having a plurality of convex portions, concave portions arranged between the plurality of convex portions, and openings arranged at the bottoms of the concave portions, the concave portions extending in a first direction, and the plurality of convex portions arranged at a distance in a second direction intersecting the first direction, and the heat-fusible fiber web is pressed along the concave portions extending in the first direction by a pressing part of a pressing member, and then a heat-fusion step in which a heated fluid, preferably hot air, is blown onto the support to form fused parts at fiber intersections in the heat-fusible fiber web. EXAMPLES

[0084] The present invention will be described in more detail below based on examples, but the present invention is not limited thereto. In the examples, "parts" and "%" are all based on mass unless otherwise specified. In Table 1 below, "-" means that the item does not have a corresponding value, etc.

[0085] Example 1 As shown below, the heat-sealable webs for the upper and lower layers were prepared, and the manufacturing method of the uneven nonwoven fabric according to the present invention was carried out. The heat-sealable web for the upper layer had two layers, an upper layer A and an upper layer B. The upper layer A used thermoplastic concentric composite short fibers with a fineness of 1.1 dtex and a sheath-core type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)). The upper layer B used thermoplastic concentric composite short fibers with a fineness of 3.3 dtex and a sheath-core type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)). The lower layer used thermoplastic concentric composite short fibers with a fineness of 2.3 dtex and a sheath-core type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)). Both fibers were coated with a hydrophilic oil. The upper layer A (weight 15g / m 2 ) and upper layer B (weight 15g / m 2 ) was formed, and the web of the upper layer A and the web of the upper layer B were laminated (forming the upper layer heat-sealable web). A concave-convex shape was formed by contacting the upper layer A side with the support roll 10 using a push-in roll 20 as a push-in member and a support roll 10 as a support as shown in FIG. 11. The support roll 10 used was the one shown in FIG. 7 and FIG. 8. The push-in roll 20 used a ring roll in which a plurality of disk-shaped rings were gathered in the CD direction and passed through a roll shaft to bundle them. The respective conditions were as shown in Tables 1 and 2. The surface temperatures of the push-in roll 20 and the support roll 10 were 50°C and 110°C, respectively. The meshing amount (meshing depth) D in the above shaping was 6 mm. Next, the lower layer (10g / m2) is carded. 2) was formed. Thereafter, the shaped upper layer heat-fusible web and the unshaped lower layer heat-fusible web were laminated so that the upper layer B and the lower layer heat-fusible web were in contact with each other, and embossed and pressed between the metal flat roll on the support roll 10. As a result, an embossed portion was formed in the groove portion surrounded by the ridges in the ridge-groove structure in which the vertical and horizontal ridges of the web were arranged in a lattice shape. The meshing shaping and embossing were performed without suctioning the web with the support roll 10. The surface temperature of the metal flat roll was 100°C. The surface that contacted the metal flat roll was the back side (lower layer). After peeling from each roll, hot air treatment was performed on the conveyor net from the surface (upper layer) convex portion 11 side at a hot air temperature of 136°C, a wind speed of 1.5 m / s, and a blowing time of 6 s to form a fiber intersection fusion portion. In this way, a nonwoven fabric sample of Example 1 was produced. The above-mentioned fiber intersection fusion parts were confirmed by the above-mentioned method using "JCM-600" (product name) manufactured by JEOL Ltd. In addition, the surface roughness Rz of the support roll (support) 10 and the pushing roll (pushing member) 20 was measured by the above-mentioned method using SJ210 (product name) manufactured by Mitutoyo Corporation. The peel resistance was measured using the heat-sealable upper web and the supports and pressing members shown in the table. The web strength was measured using the above-mentioned embossed and pressed samples.

[0086] (Examples 2 to 4) The manufacturing methods of the uneven nonwoven fabrics of Examples 2 to 4 were carried out in the same manner as in Example 1, except that the conditions were as shown in Tables 1 and 2, and uneven nonwoven fabric samples of Examples 2 to 4 were produced. In Examples 2 to 4, the surface roughness Rz in the depth direction of the support was made different from that of Example 1.

[0087] (Comparative Examples 1 to 3) The manufacturing methods of the uneven nonwoven fabrics of Comparative Examples 1 to 3 were carried out in the same manner as in Example 1, except that the conditions were as shown in Tables 1 and 2, and uneven nonwoven fabric samples of Comparative Examples 1 to 3 were produced. In Comparative Examples 1 to 3, the surface roughness Rz in the depth direction of the support was made significantly different from that of Examples 1 to 4. In Comparative Example 3, the peel resistance of the pushing member was higher than the peel resistance of the support, so that the web was held on the pushing member side after meshing.

[0088] Example 5 As shown below, the heat-bondable webs for the upper and lower layers were prepared, and the manufacturing method of the uneven nonwoven fabric according to the present invention was carried out. The heat-bondable web for the upper layer had two layers, an upper layer A and an upper layer B, and the heat-bondable web for the lower layer had two layers, a lower layer A and a lower layer B. For the upper layer A, thermoplastic concentric composite short fibers with a fineness of 1.8 dtex and a sheath-core type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)) were used. For the upper layer B, thermoplastic concentric composite short fibers with a fineness of 2.3 dtex and a sheath-core type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)) were used. For the lower layers A and B, thermoplastic concentric composite short fibers with a fineness of 2.3 dtex and a sheath-core type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)) were used. Both fibers were coated with a hydrophilic oil. The upper layer A (weight 8g / m 2 ) and upper layer B (weight 8g / m 2 After stacking these layers, hot air treatment was performed on the surface (upper layer B) side on a conveyer net at a hot air temperature of 136°C, a wind speed of 1.5 m / s, and a blowing time of 6 s to form fused fiber intersections, thereby obtaining a flat-shaped upper layer hot air-treated nonwoven fabric. Next, the fibers for the lower layer were used in a carding machine to form the lower layer A (basis weight 8 g / m 2 ) and lower layer B (weight 8g / m 2After stacking these layers, hot air treatment was performed on the surface (lower layer B) side on a conveyer net at a hot air temperature of 136° C., a wind speed of 1.5 m / s, and a blowing time of 6 s to form fused fiber intersections, thereby obtaining a lower layer hot air-treated nonwoven fabric 401 having a flat shape. The hot air treated nonwoven fabric of the upper layer was used and shaped by a push-in roll 20 as a push-in member and a support roll 10 as a support as shown in Fig. 11 so that the upper layer A side was in contact with the support roll 10 to form an uneven shape. The support roll 10 and the push-in roll 20 were the same as those used in Example 1. The surface temperatures of the push-in roll 20 and the support roll 10 were 60°C and 130°C, respectively. The meshing amount (pushing depth) D in the shaping was 3 mm. Thereafter, the shaped upper hot air treated nonwoven fabric and the unshaped lower hot air treated nonwoven fabric were laminated so that the upper layer B and the lower layer A were in contact with each other, and embossed and fused between a metal flat roll on a support roll 10 to obtain an embossed nonwoven fabric having an embossed portion 3. The intermeshing shaping and embossing were performed without suctioning the web with the support roll 10. The surface temperature of the flat roll was 125°C. Other than the above, the same procedures were followed as in Example 1. In this manner, a nonwoven fabric sample of Example 5 was produced. The hot air treated nonwoven fabric 401 was used for measuring each peel resistance, and measurements were made using each support and pressing member shown in the table. The web strength was measured using a nonwoven fabric sample after embossing and fusion.

[0089] (Examples 6 to 8) The manufacturing methods of the uneven nonwoven fabrics of Examples 6 to 8 were carried out in the same manner as in Example 5, except that the conditions were as shown in Tables 3 and 4, and uneven nonwoven fabric samples of Examples 6 to 8 were produced. In Examples 6 to 8, the surface roughness Rz in the depth direction of the support was made different from that of Example 5.

[0090] (Comparative Examples 4 and 5) The manufacturing methods of the uneven nonwoven fabrics of Comparative Examples 4 and 5 were carried out in the same manner as in Example 5, except that the conditions were as shown in Tables 3 and 4, and uneven nonwoven fabric samples of Comparative Examples 4 and 5 were produced. In Comparative Examples 4 and 5, the surface roughness Rz in the depth direction of the support was made significantly different from that of Examples 6 to 8.

[0091] The nonwoven fabric samples of each of the Examples and Comparative Examples were subjected to the following tests. The following tests (1) to (3) were performed based on the respective measurement methods described above. (1) Measurement of peel resistance of shaped web (2) Measurement of mean coefficient of friction (MIU) (3) Evaluation of the peeling state of the shaped web The peeling state of the shaped web from the support was evaluated. The evaluation was based on whether the shaped web was caught on the wall surface of the protrusion of the support. The evaluation was based on whether the shaped web was caught on the wall surface of the protrusion of the support. The evaluation was based on whether the web was not caught on the wall surface of the protrusion of the support. The evaluation was based on whether the web was caught on the wall surface of the support.

[0092] The results of the above evaluations are shown in Tables 2 and 4 below.

[0093] [Table 1]

[0094] [Table 2]

[0095] [Table 3]

[0096] [Table 4]

[0097] As shown in Tables 2 and 4, in each Example, there was no lifting during shaping, and peeling from the support or indentation was performed normally. [Explanation of symbols]

[0098] 10 Support 11 Convex 11B Bottom of protrusion 11T Top of the protrusion 11S Wall 11E Corner 11P near the top 11M Projected part (part where the pressed part is projected in the CD direction against the convex part) 12 Recess 13 Base material 20 Push-in member 21 Push-in section 22 Space section 23 Base material 30 Web D Engagement amount (push depth) W Gap Distance M Projected cross-sectional area

Claims

1. A support roll having a convex or concave portion and a push-in roll having a push-in portion that can be engaged with the support roll are engaged with each other to form a convex or concave shape on a web made of an aggregate containing fibers, and the peel resistance per unit area when peeling the shaped web from the support roll is 300 cN / m ２ More than 20000cN / m ２ The following: A method for producing a nonwoven fabric having a concave-convex shape, wherein the convex portion of the support roll has a larger circumferential cross-sectional area at the top than at the bottom.

2. When a web consisting of an aggregate containing fibers is shaped into unevenness by meshing a support roll having a convex or concave portion with a push-in roll having a push-in portion capable of meshing with the support roll, the peel resistance per unit area when peeling the shaped web from the support roll is set to 300 cN / m2 or more and 20,000 cN / m2 or less, A method for producing a concave-convex nonwoven fabric, comprising the steps of: making the surface roughness Rz (maximum height) of at least a portion of the wall surface of the convex portions of the support roll 1 μm or more and 75 μm or less.

3. A method for manufacturing a textured nonwoven fabric as described in claim 2, wherein the surface roughness Rz of the wall surface of the pushing portion of the pushing roll is smaller than the surface roughness Rz of the wall surface of the convex portion of the support roll.

4. The method for producing a nonwoven fabric according to any one of claims 1 to 3, wherein the peel resistance per unit area when the shaped web is peeled off from the support roll is greater than the peel resistance per unit area when the shaped web is peeled off from the push roll.

5. The peel resistance per unit area when peeling the shaped web from the push roll is 0 cN / m ２ More than 1000cN / m ２ The method for producing a nonwoven fabric according to any one of claims 1 to 4, wherein:

6. A method for producing a textured nonwoven fabric described in any one of claims 1 to 5, wherein the web is a heat-fusible web consisting of unfused fibers that can be fused.

7. A method for manufacturing a textured nonwoven fabric described in any one of claims 1 to 6, wherein the gap distance W1 between the convex portions of the support roll is 0.5 mm or more and 10 mm or less.

8. A method for manufacturing a textured nonwoven fabric described in any one of claims 1 to 7, wherein the gap distance W2 between the pushing portions of the pushing roll is 1 mm or more and 14 mm or less.

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