JP7597616B2 - Nonwoven fabric manufacturing method - Google Patents

Description

The present invention relates to a method for producing nonwoven fabric.

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 nonwoven fabric with a concave-convex shape, in which an unfused fiber web is placed on a support having a protrusion, 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. 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. In this production method, it is described 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 describes that suction ports are formed in the tooth grooves of each gear in the first roll, and the projections and recesses of the upper layer are 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 fibrous 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 a first corrugating member used in the forming has a rough finish (formed, for example, by sandblasting) and a second corrugating member has a smooth polished finish, and the nonwoven fibrous sheet preferentially rests along the surface of the first corrugating member. It also describes that the ridges of both corrugating members can be oriented in the range of 0 (parallel to the axis) to 90 degrees relative 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 is then joined 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.

JP 2019-112748 A JP 2020-000467 A JP 2019-112747 A Special Publication No. 2002-531726 JP 2004-174234 A Special Publication No. 2001-522700 JP 2010-111003 A

In the conventional method for producing a nonwoven fabric having a concave-convex shape, after the concave-convex shape is formed by the meshing of 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 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 to each other and nonwoven fabrics in which the fibers are heat-fused to each other (hereinafter, in the present invention, these are collectively referred to as webs) are formed into concave-convex shapes.
In this regard, if the suction described in Patent Documents 3 and 5 is used to suppress the return of the web, 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 it is difficult to maintain a sufficient temperature. In addition, the suction port is prone to fiber clogging, and furthermore, the thickness of the support, etc. is effectively reduced by the suction port, 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. It does not take into consideration the suppression of the return of the web due to centrifugal force acting while the web is held on the support. Similarly, the above Patent Document 2 describes the surface roughness of the female material (pushing member), but does not describe the male material (support), and does not take into consideration the suppression of the return of the web due to centrifugal force 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 wind 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. Patent Document 6 describes a rough finish for the first corrugated member corresponding to the support, and 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.

In view of the above, the present invention relates to a method for producing a nonwoven fabric with a concave-convex shape that can suppress lifting of the web from the support.

The present invention provides a method for producing a nonwoven fabric having a concave and convex portion, in which a support having a convex or concave portion is meshed with a pushing member having a pushing portion that can mesh with the support, thereby forming a web consisting of an aggregate containing fibers into a concave and convex shape, and the peel resistance per unit area when peeling the shaped web from the support is 300 cN/ ^m2 or more and 20,000 cN/m2 or ^less .

The manufacturing method of the uneven nonwoven fabric of the present invention can suppress lifting of the web from the support and produce an uneven nonwoven fabric with a good uneven shape.

1A and 1B are explanatory diagrams showing an example of the unevenness forming step in the manufacturing method of the uneven nonwoven fabric of the present invention. 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. FIG. 2 is a cross-sectional view showing a preferred embodiment of a convex shape on a support together with a web. 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. 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. 1A and 1B are explanatory diagrams showing a schematic cross-sectional area 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 from above, and (B) is a side view of the convex portion from the side. FIG. 2 is a perspective view showing a preferred embodiment of a support; FIG. 8 is a side view of the support shown in FIG. 7 as seen in the CD direction. 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. 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. 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.

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 the MD (machine direction), and the width direction perpendicular to the conveying direction is referred to as the CD (cross direction).

The method for producing a nonwoven fabric with a concave-convex shape of the present invention includes a step of forming a web made of an aggregate containing fibers into a concave-convex shape by engaging a support having a convex or concave portion with a pushing member having a pushing portion that can engage with the support.

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, a portion that protrudes higher than the substrate constituting the support is a convex portion, and a portion between the convex portions is a concave portion. 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 a concave-convex 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, a concave-convex roll, a net, a belt, a chain, a leaf spring (elastic plate-like body), 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.

"Match so as to be able to mesh" means that the recess of the support and the pushing portion of the pushing member are arranged in a corresponding manner, and the pushing portion fits into the recess while leaving a gap between the protrusion of the support and the pushing portion of the pushing member large enough for the web to fit in between. 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.

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.).
The term "thermally fusible web" refers to an aggregate of unfused 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 step. More specifically, those that do not have the strength of a nonwoven fabric and have a maximum tensile strength of 100 cN/50 mm or less in the MD and CD directions are considered to be thermally fusible webs. For example, card webs are included.

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, 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 its 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. This can be done by observing the cross section of the fused fiber joint with a scanning electron microscope (SEM).

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 method.
Staple fibers are fibers having a length of 77 mm or less, and are used in air-through nonwoven fabrics, spunlace nonwoven fabrics, and airlaid nonwoven fabrics.

Methods for supplying heat-bondable webs include the spunbond method (before embossing, continuous fibers), electrospinning method (continuous fibers), spunmelt method (a method that combines hot air stretching and cold air stretching, long fibers), meltblown method (long fibers), carding method (short fibers), and airlaid method (short fibers). The spunbond method and carding method are particularly preferred because they produce bulky, three-dimensionally shaped nonwoven fabrics. It is also possible to combine these supply methods.

The fiber material preferably contains thermoplastic fibers, and examples of such fibers 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 and a low melting point component is the sheath, 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 having a core-sheath structure in which the sheath component is polyethylene or low melting point polypropylene, and representative examples of the fiber having the core-sheath structure include fibers having 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.

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.

1(A) and (B) show an example of the unevenness forming process in the method for producing the uneven nonwoven fabric of the present invention. That is, as shown in FIG. 1(A), a web 30 is placed on a support 10 in which a plurality of convex portions 11 are arranged at a predetermined interval on a substrate 13, and the convex portions 11 are spaced apart from each other to form concave portions 12. Next, as shown in FIG. 1(B), a pressing member 20 is pressed against the web 30 from above. The pressing member 20 has a plurality of pressing portions 21 at a predetermined interval on the substrate 23, and the pressing portions 21 are engaged with the concave portions 12 of the support 10. As a result, the web 30 is partially pressed into the concave portions 12. As a result, the convex portions 11 of the support 10 are engaged with the spaces 22 between the pressing portions 21, 21 of the pressing member 20. As a result, the web 30 is partially pressed into the spaces 22. In this way, the web 30 is unevenly shaped.

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, thereby forming an uneven nonwoven fabric. 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, so that even if the shaped shape is once 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.

The obtained uneven nonwoven fabric can be used as a top sheet for absorbent articles such as sanitary napkins and disposable diapers, a back sheet on the clothing side, a sweat-absorbing sheet, or the wings of sanitary napkins. 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. It can also be used in various absorbent articles other than diapers, such as sanitary napkins.

In the manufacturing method of the uneven nonwoven fabric of the present invention, the support and web are configured as follows when shaping. This makes it possible to suppress the web from lifting off the support after shaping and to manufacture an uneven nonwoven fabric with a good uneven shape.

First, regarding the support, the peel resistance per unit area when peeling the shaped web from the support (hereinafter also referred to as support peel resistance E1) is set to 300 cN/m ² or more and 20,000 cN/m ² or less.
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 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. In addition, it is preferable that the wind speed is 0 m/s or more (no suction or blowing is performed).

From the viewpoint of more effectively suppressing lifting of the shaped web, the support peel resistance E1 is preferably 1000 cN/m ² or more, and more preferably 6000 cN/m ² or more.

In addition, by setting the support peel resistance E1 to 20,000 cN/m2 ^{or less} in consideration of the web strength, the shaped web can be easily peeled off from the support without breaking even if the web has low web strength. Therefore, the web can be peeled off smoothly while maintaining the uneven shape well.
From this viewpoint, the support peel resistance E1 is preferably 15000 cN/m ² or less, and more preferably 10000 cN/m ² or less.

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.

From this viewpoint, the ratio (E1/E2) of the support peel resistance E1 to the indentation member peel resistance E2 is preferably 4 or more, more preferably 10 or more, and even more 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.

Furthermore, the pushing member peel resistance E2 is preferably set to 0 cN/ ^m2 or more and 2000 cN/m2 ^or less. This makes it possible to more effectively prevent the shaped web from being pulled in the pulling direction of the pushing member. As a result, the unevenness height of the shaped web is more effectively maintained.
From the above viewpoint, the pushing member peel resistance E2 is preferably 10 cN/m ² or more, more preferably 50 cN/m ² or more, and even more preferably 100 cN/m ² or more.
Further, the pushing member peel resistance E2 is preferably 2000 cN/m2 or ^less , more preferably 1000 cN/m2 or ^less , even more preferably 500 cN/m2 or ^less , and even more preferably 280 cN/m2 or ^less .

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/ ^m2 ) = 0.1 x W x ( ^v2 /r)
W: Web mass per unit area (g/m ² )
v: Machining speed (m/s)
r: radius (m)

Since the centrifugal force is proportional to the square of the processing speed v, the faster the processing speed v, the larger 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 prominent. A practical processing speed v is preferably 1000 m/min or less, more preferably 600 m/min or less. In addition, when the centrifugal force is preferably 10 cN/m ² or more, more preferably 100 cN/m ² or more, and even more preferably 200 cN/m ² or more, the effect of the present application becomes more prominent. From the viewpoint of lowering the centrifugal force than the support peeling resistance E1, the centrifugal force is preferably 20000 cN/m ² or less, more preferably 15000 cN/m ² or less, and even more preferably 10000 cN/m ² or less.

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 using the web after peeling from the support, and dividing the value by the CD width of the sample. The CD width of the sample is measured at its full width if the width is 0.5 m or less, and cut to 0.5 m if the width is 0.5 m or more. The chuck width used for the measurement is 50 mm, and the sample is folded in the CD direction and measured. The measurement environment is a temperature of 23°C ± 2°C and a humidity of 65% RH ± 5% RH. Five samples are measured, and the average value is calculated.

The support peel resistance E1 can be measured by the method shown 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 meshing amount. However, if push-in members of the same type cannot be engaged with each other (e.g., nets), a support having the same shape and small surface roughness (e.g., a support having a surface roughness Rz of 0.1 μm or less on the side of the convex portion) is used so that the web remains 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 member, etc. are performed, they are performed under the conditions for actually manufacturing the nonwoven fabric.
(2) The processing speed (roll peripheral speed) is set to 5 m/min, and the web is released from the pushing section and stopped in the state where the web on the support is shaped. At this time, if support suction, blowing, support heating, or pushing member heating is being performed, these are stopped.
(3) Prepare a stainless steel plate of 30 mm x 30 mm with a thickness of 1 mm. If the support has a curvature, such as a roll, process the plate so that it follows the curvature of the support. Attach a string or the like to the square corners of the back surface of the stainless steel plate and connect it to a push-pull gauge. Next, attach a double-sided adhesive tape of 30 x 30 mm square (TERAOKA No. 777 (product name, manufactured by Teraoka Seisakusho Co., Ltd.) or an equivalent product) to the lower surface of the stainless steel plate, and place a weight on the top of the stainless steel plate so that the total weight applied to the push-pull gauge is 50 gf. In this state, the zero point of the push-pull gauge is set.
(4) Immediately after stopping, the following measurements (5) to (7) are carried out quickly. The measurement area 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 having 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. The peeled web mass is then measured and subtracted from the measured value to determine the peel strength (cN/900 mm ² ).
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) Measurements are taken at different points, and the average value is converted into strength per square ^meter to determine the web peel resistance (cN/m ² ).

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 generated between the constituent fibers of the web and the convex portions of the support. The "repulsive force" is the elastic force of the constituent fibers trying to spread in the limited space of the concave portion when the web is pressed into the concave portion between the convex portions, and is the force pushing against the convex portions (arrow F2 in FIG. 2).

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 certain 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 F1 when peeling the web 30 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.

The factors of the friction coefficient and the repulsive force are derived from the support side and the web side, respectively. Each factor is explained below.

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

[1] Percentage (%) of the bottom cross-sectional area of the protrusion 11 to the top cross-sectional area ([top cross-sectional area]/[bottom cross-sectional area])×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 defined as the "bottom cross-sectional area" and the cross-sectional area in the circumferential direction at the top 11T is defined as 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 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.
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.

In the above relationship of top cross-sectional area>bottom cross-sectional area, ([top cross-sectional area]/[bottom cross-sectional area])×100 in the convex portion 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]) x 100 of the convex portion 11 is preferably 180% or less, more preferably 150% or less, and even more preferably 120% or less.

[2] Uneven shape at corners 11E and near apex 11P of protrusions 11 As shown in Fig. 4(A), when the wall surface 11S of the protrusion 11 has corners 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 corners 11E. Similarly, it is preferable that a micro uneven shape is arranged at the near apex 11P. The corners 11E and near apex 11P are the parts of the protrusions 11 where the constituent fibers of the web are likely to get caught, and by arranging a micro uneven shape at these parts, the friction coefficient can be increased more effectively.
Furthermore, it is more preferable that such micro-convex and concave shapes are arranged on the wall surfaces 11S between the corners 11E, in addition to the corners 11E and the vicinity 11P of the top of the protrusion 11.

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 it is easier to form the micro-irregular shape at corners adjacent to surfaces parallel to the MD direction than at corners adjacent to 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 because the fibers come into contact with the wall surface 11S of the protrusions 11 and their corners 11E as shown in Figure 6 described below, thereby increasing the frictional force at that time.

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 portion 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.
4B is an example of the micro-uneven shape of the convex portion 11 formed by grinding. The top-side approximate inclination angle A has an inclination angle toward the bottom portion 11B side of the convex portion 11. The bottom-side approximate inclination angle B has an inclination angle toward the top portion 11T side of the convex portion 11.
4C 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.
4(D) is an example of the micro-roughness of the convex portion 11 formed by thermal spraying. The top-side approximate inclination angle A has an inclination angle toward the bottom portion 11B side of the convex portion 11. The bottom-side approximate inclination angle B has an inclination angle toward the top portion 11T side of the convex portion 11.

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

(Method of measuring top side approximate inclination angle A and bottom side approximate inclination angle B)
First, observation is performed using a microscope at a magnification 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 convex portion 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 formed by 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 defined as the top side approximate inclination angle A and the bottom side approximate inclination angle B, respectively.

In the case of the example in which the micro-convex/concave shape is a mountain shape 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, if the micro-convex 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.

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 the 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 greater than the bottom-side approximate inclination angle B. In this magnitude relationship, the difference (A-B) 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 (A-B) 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.

[3] Surface roughness Rz of the wall surface 11S of the protrusion 11
The high surface roughness Rz of the wall surface 11S of the protrusions 11 increases the coefficient of friction, making it easier for the constituent fibers of the web to become caught, and 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.
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 even more 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.

(Method of measuring surface roughness)
The surface roughness (maximum height) Rz of the wall of the projection of the support is measured in accordance with ISO 4287-1997.
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, tip angle of the stylus probe 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 is peeled off from the protruding portion.
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.

[4] Amount of meshing 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 recess 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 recess 12, and the contact area with the wall surface 11S of the protrusion 11 increases. This increases the frictional force between the pushed-in web 30 and the protrusions 11, i.e., the support peeling 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.
Furthermore, 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.

Next, the factors on the support side that increase the repulsive force will be explained using [1] and [2] below.

[1] Gap distance W1 between convex portions 11, 11
5, by reducing the gap distance W1 between the convex portions 11, 11, the web 30 pressed into the concave portion 12 by the pressing portion 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 convex portions 11, and increases the frictional force between the support 10 and the web 30, i.e., the support peeling resistance force E1. In particular, the radius of curvature R2 of the curved web 30 on the top 11T side of the convex portion 11 becomes smaller than the radius of curvature R1 of the curved web 30 on the bottom 11B side of the convex portion 11.
From this viewpoint, the gap distance W1 between the convex 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 strength when making the convex portion of the pushing member 20 thin.
In addition, when the convex portions 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 convex portions 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 convex portions 11 having such a tapered shape. When the convex portions 11 have a tapered shape, etc., the gap distance W1 is the average spacing distance between the convex portions 11, 11 in the range from the top 11T to the meshing amount D.

[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 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 convex portion 11 (mainly the wall surface 11S) when the web 30 pushed in by the engagement of the support 10 and the pushing member 20 is observed in the CD direction. 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 convex portion 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 extending continuously in the MD direction as shown in Fig. 6(A). In this case, as shown in Figs. 6(A), 7 and 8, when the convex portions 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 convex portions 11 in the row of adjacent convex portions 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 connecting 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.

The projected cross-sectional area ratio in the CD direction can be calculated by the following formula.
Projected cross-sectional area ratio=(average opposing length per pitch between convex portions×amount of meshing of opposing portions)/(one pitch length×amount of meshing of opposing portions)×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 indentation portion 21, and is shown as an amount of meshing 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 indentation 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 an 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 amount of meshing 8D (11D).
The denominator in the above formula (one pitch length × meshing amount of each portion) is shown by the reference symbol 8M in Fig. 6(B), and the numerator (average opposing length per pitch between convex portions × meshing amount of opposing portions) is shown by the reference symbol 11M in Fig. 6(B). That is, the above projected cross-sectional area ratio is 11M/8M.

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 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 an intermediate ridge portion extending in the CD direction between the convex portions 11, 11 to increase the resistance of the uneven nonwoven fabric to compression collapse.

Next, the factors on the web side that increase the support peel resistance E1 are explained below.

[1] Fiber oil (fiber treatment agent) contained in the web 30
By using a textile oil having a high friction coefficient as contained in the web 30, the friction coefficient of the web 30 with respect to the support 10 increases, and the frictional force between the support 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 fiber 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 fiber oil with a low friction coefficient for the second layer 32 on the top 11T side of the protrusions 11. From the above-mentioned viewpoint, the amount of fiber oil relative to the fiber weight is preferably 0.2 mass % or more and 0.6 mass % or less, more preferably 0.3 mass % or more and 0.5 mass % or less, which reduces peeling of the web 30 from the support 10 and reduces accumulation of the fiber oil due to adhesion to the support 10, resulting in favorable results.
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 prepared by subjecting a flat web 30 to an air-through heat treatment on a conveyor net without forming the uneven shape, using the respective fibers for the first and second layers, with one having the first layer being the net surface and the other having the second layer being the net surface, and these are used to measure the average friction coefficient.
Moreover, since the textile oil accumulates on the support 10 as the operating time of the manufacturing process progresses, the peel resistance gradually increases. In order to make the peel resistance at the start of the manufacturing process an appropriate value, it is preferable to set the average coefficient of friction (MIU) to 0.2 or more and 0.33 or less.

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

[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 make the fiber diameter of the constituent fibers of the second layer 32 on the top 11T side of the protrusions 11 in the support 10 (the R2 side where the radius of curvature of the pressed-in web 30 is small) thicker. In this case, it is preferable to make the fiber diameter of the constituent fibers of the first layer 31 on the bottom 11B side of the protrusions 11 in the support 10 (the R1 side where the radius of curvature of the pressed-in web 30 is large) thinner. 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 peeling resistance. From the above viewpoints, the ratio of the average fiber diameter on the pushing member 20 side to the average fiber diameter on the support 10 side (latter/former) is preferably 1.1 or more, more preferably 1.5 or more, and is preferably 3.5 or less, more preferably 3.0 or less, which is preferable in order to obtain a nonwoven fabric with little uneven texture.

(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 thickness direction cross section 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, i.e., the side irradiated with electron beams. 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, i.e., the width in the direction perpendicular to the longitudinal direction of the fibers, 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 in the thickness direction of the nonwoven fabric, and the cross-sectional area is calculated from the cross-sectional shape of the selected fibers. The fiber diameter is calculated from the diameter of the fibers when they are assumed to be circular.

[3] Thickness of the web 30 It is preferable to increase the thickness of the web before shaping (at a load of 0.5 g/ ^cm2 ). This increases the repulsive force of the web 30 when the push-in portion 21 engages with the protrusions 11 and pushes the web 30 in, thereby increasing the frictional force, i.e., the support peel resistance 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. Moreover, from the viewpoint of enabling smooth pushing 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.

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.
In addition, as opposed to appropriately increasing the peel resistance between the support 10 and the web 30, it is preferable that the pushing member 20 has a reduced peel resistance with the web 30. That is, it is preferable that the pushing member 20 has a configuration opposite to the above-mentioned configuration of the support 10. This makes it easier for the web 30 to remain favorably on the top part 11T side of the support 10 when the pushing member 20 is pulled out from the web 30 pushed into the recess 12 of the support 10, which is preferable.

The methods for reducing the peel resistance force E2 of the pushing member 20 are explained below using [1] to [5].

[1] Percentage (%) of the bottom cross-sectional area of the indentation portion 21 to the top cross-sectional area ([top cross-sectional area]/[bottom cross-sectional area])×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 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]) x 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, in order to ensure the strength of the pushing portion 21 of the pushing member 20, ([top cross-sectional area]/[bottom cross-sectional area]) x 100 in the pushing portion 21 is preferably 10% or more, more preferably 20% or more, and even more preferably 30% or more.

[2] Shape of the corners 21E and the vicinity of the apex 21P of the pressing portion 21 When the wall surface 21S of the pressing portion 21 of the pressing member 20 has corners 21E, it is preferable that the above-mentioned micro uneven shape is not arranged at the corners 21E. Similarly, it is preferable that the vicinity of the apex 21P is also not arranged with a micro convex shape. The corners 21E and the vicinity of the apex 21P are the parts of the pressing 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.

[3] Surface roughness Rz of the wall surface 21S of the pressing portion 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 wall surface 21S of 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 former/latter ratio is preferably 2 to 100, and more preferably 10 to 70.
The above surface roughness Rz is preferably in an area of 20% or more of the area of the wall surface 21S of the pressing 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 in the case of the protrusion 11.

[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 recess 12 by the push-in portion 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 portion 21, and reduces the frictional force between the push-in member 20 and the web 30, i.e., the peeling resistance force E2. At this time, the peeling 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 peeling resistance force E2 is relatively greater.
From this viewpoint, the gap distance W2 between the pushing portions 21, 21 of the pushing 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 within 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.
In addition, 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 spacing distance between the push-in portions 21, 21 in the range from the top 21T to the meshing amount D.

[5] Projected cross-sectional area ratio in the CD direction where the pushing-in portion 21 of the pushing-in member 20 and the web 30 come into contact when the support 10 and the pushing-in member 20 are engaged The above-mentioned projected cross-sectional area ratio in the CD direction is determined by the same method as the 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.

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-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 erected perpendicularly 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 difficult to collapse 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 pushing member 20 may be provided with a lattice-shaped pushing 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 pushing portion 21 along the MD direction of the lattice-shaped recesses 12 of the support 10. Also, the pushing member 20 may be provided with a pushing portion 21 along the CD direction of the recesses 12 of the support 10. An example of a pushing member 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 collected in the CD direction and bundled by passing them through a roll shaft. Also, 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 pushing-in portion 21 at the position of half the meshing amount D is 50% or less in the MD direction 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 direction or CD direction, intermediate ridges connecting the ridges in the CD direction 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 pushing-in portion 21 by passing them through a roll shaft is used as the pushing member 20, the ratio of the circumferential length in the MD direction in which the teeth of the gear roll exist at the position of half the meshing amount D can be less than 50%.

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.

The manufacturing apparatus 200 shown in FIG. 11 includes a web supply unit 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 unit 102, and a nip roller 106 that pressurizes the heat-fusible web 300 transported by the conveyor belt 104. Downstream of the web supply unit 102, there are 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 recess 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, and a two-layered, solid-structured, uneven nonwoven fabric is produced. 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.

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 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. The conveyor belt 104, the nip roller 106, and the cooling roll 114 may not be used as appropriate, but it is preferable to provide them for stable production. The web supply unit 102, the conveyor belt 104, the nip roller 106, and the cooling roll 114 may be of various configurations that are normally used.

In the manufacturing apparatus 200 having the above configuration, first, the heat-fusible web 300, which is the raw material to be processed, 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 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 the 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 force when the support roll 10 and the push roll 20 are engaged. In this way, the reduction of the pressed parts due to peeling increases the freedom of the fibers and provides excellent texture, which is preferable. In addition, even if a part of the pressed part remains, since the pressed part is not a fused part, it does not cause a decrease in texture due to catching.

In addition, in the manufacturing apparatus 200, the web supply unit 102 is shown as supplying a single layer of heat-sealable web 300, but is not limited to this. For example, the web supply unit 102 may be equipped with 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 roll 20 impart unevenness to the entire laminate.

After the heat-sealable web 300 reaches the meshing portion of the support roll 10 and the push roll 20, an uneven shape is formed in the heat-sealable web 300 by the meshing with the support roll 10 and the push 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 (process (II)) simultaneously with shaping by the 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 adhered to 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 while maintaining the state in which the uneven shape is formed by the rotation of the support roll 10. By sandwiching the convex or concave portion of the support roll 10 between the point bonding means 130 and the convex portion 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 the cooling roll 114 to be cooled, and is then transported by the 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.
In addition, if 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 made only from the shaped web 301 is produced.

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 circumferential surface and those with a convex structure on the circumferential surface. Examples of the ultrasonic device include those with a flat circumferential surface (arc-shaped or planar) and those with a convex structure on the circumferential 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.

The embossed portion formed by the embossing heat fusion process or the embossing pressure bonding process refers to the 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-to-fiber fusion portion" refers to the portion where the fibers are fused without being crushed, unlike the "pressure fusion" or "pressure bonded" portions described below.

"Pressure fusion" means that the resin of at least one fiber at the bonding interface between the fibers is melted by pressure and heat (due to intermolecular friction, self-heating due to compression, or external heating) and bonded 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 some resins that make up the fibers have a melting point that decreases due to pressure, the heating temperature (surface temperature of a 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 ellipse having the same cross-sectional area.

"Compression bonding" means that one fiber adheres to another fiber without the resin being melted by 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 by which the fibers adhere (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 the 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. For the observation of the cross section at 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.

When the web 30 is formed into an uneven shape by meshing with the support roll (support) 10 and the push 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, as 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 high, between 3.5 mm and 10 mm.

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 shape can take a variety of 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 becomes a support roll for the first roll, and a push-in 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 way. 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, and the multiple rolls may be arranged so that they can intermesh with the first roll, respectively. 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.

The manufacturing method for the uneven nonwoven fabric of the present invention shows more remarkable effects when used with the manufacturing method and manufacturing equipment described below.

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:

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.

Furthermore, 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 protrusions, a plurality of recesses arranged between the protrusions, and an opening arranged at the bottom of the recesses, the recesses extending in a first direction, and the plurality of protrusions arranged at a distance in a second direction intersecting the first direction, and the heat-fusible fiber web is pressed along the recesses 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.

The present invention will be explained in more detail below based on examples, but the present invention should not be construed as being limited thereto. In 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.

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 of a core-sheath type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)) with a fineness of 1.1 dtex. The upper layer B used thermoplastic concentric composite short fibers of a core-sheath type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)) with a fineness of 3.3 dtex. The lower layer used thermoplastic concentric composite short fibers of a core-sheath type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)) with a fineness of 2.3 dtex. Both fibers were coated with a hydrophilic oil agent.
A heat-sealable web of upper layer A (15 g/m ² basis weight) and upper layer B (15 g/m ² basis weight) was formed by a carding machine, and the web of upper layer A and the web of upper layer B were laminated (forming the heat-sealable web of the upper layer). A concave-convex shape was formed by contacting the upper layer A side with the support roll 10 using a push roll 20 as a push 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 roll 20 used a ring roll in which a plurality of disk-shaped rings were collected 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 roll 20 and the support roll 10 were 50° C. and 110° C., respectively. The meshing amount (meshing depth) D in the shaping was 6 mm.
Next, a lower layer (10 g/m ² weight) of heat-sealable web was formed by a carding machine. Thereafter, the shaped upper layer heat-sealable web and the unshaped lower layer heat-sealable web were laminated so that the upper layer B and the lower layer heat-sealable 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 in contact with the metal flat roll was the back side (lower layer) side. After peeling from each roll, hot air treatment was performed on the surface (upper layer) convex portion 11 side on the conveyor 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. 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. 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.

(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.

(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.

Example 5
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, and the heat-sealable 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 of a core-sheath type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)) with a fineness of 1.8 dtex were used. For the upper layer B, thermoplastic concentric composite short fibers of a core-sheath type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)) with a fineness of 2.3 dtex were used. For the lower layers A and B, thermoplastic concentric composite short fibers of a core-sheath type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 5:5 (mass ratio)) with a fineness of 2.3 dtex were used. For both layers, a hydrophilic oil agent was applied.
A carding machine was used to form a heat-fusible web of an upper layer A (basis weight 8 g/ ^m2 ) and an upper layer B (basis weight 8 g/ ^m2 ). After these were laminated, 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 intersection parts, thereby obtaining a flat-shaped upper-layer hot-air-treated nonwoven fabric.
Next, a carding machine was used to form a heat-fusible web of a lower layer A (basis weight 8 g/ ^m2 ) and a lower layer B (basis weight 8 g/ ^m2 ) using the fibers for the lower layer. After these were laminated, hot air treatment was performed on the surface (lower layer B) side on a conveyor net at a hot air temperature of 136°C, a wind speed of 1.5 m/s, and a blowing time of 6 s, forming fused fiber intersection parts and 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 a concave and convex shape was formed by forming a shape with a pressing roll 20 as a pressing 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. The support roll 10 and the pressing roll 20 were the same as those used in Example 1. The surface temperatures of the pressing roll 20 and the support roll 10 were 60°C and 130°C, respectively. The meshing amount (pressing depth) D in the shaping was set to 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 was in contact with the lower layer A, 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 carried out 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 above 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.

(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.

(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.

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 average coefficient of friction (MIU) (3) Evaluation of peeling state of shaped web The peeling state of the shaped web from the support was evaluated. The evaluation was made based on whether the shaped web was caught on the wall surface of the protruding part of the support. The evaluation was made as normal if the web was not caught, and abnormal if the web was caught.

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

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.

10 Support 11 Convex portion 11B Bottom portion of convex portion 11T Top portion of convex portion 11S Wall surface 11E Corner portion 11P Near the top portion 11M Projected portion (portion that faces the convex portion when the indentation portion is projected in the CD direction)
12 Recess 13 Substrate 20 Push-in member 21 Push-in portion 22 Space portion 23 Substrate 30 Web D Amount of meshing (pushing depth)
W Gap distance M Projected cross-sectional area

Claims (8)

When a web made of an aggregate containing fibers is formed into an uneven shape 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 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 . 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 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. The method for producing a concave-convex nonwoven fabric according to 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. 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 . The method for producing a nonwoven fabric according to any one of claims 1 to 4 , wherein the peel resistance per unit area when peeling the shaped web from the push roll is 0 cN/ ^m2 or more and 1000 cN/m2 or ^less . The method for producing a concave-convex nonwoven fabric according to any one of claims 1 to 5, wherein the web is a heat-fusible web made of fusible unfusible fibers. The method for producing a concave-convex nonwoven fabric according to 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. The method for producing a concave-convex nonwoven fabric according to any one of claims 1 to 7, wherein the gap distance W2 between the pushing portions of the pushing rolls is 1 mm or more and 14 mm or less.

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