Manufacturing method and manufacturing device for composite sheet

Abstract

To provide a manufacturing method and a manufacturing apparatus for a composite sheet capable of performing a formation of a welded portion and a formation of a through hole in one step in manufacturing of the composite sheet formed with a through hole at the welded portion.SOLUTION: A manufacturing method for a composite sheet has: a superposition step for superposing a first sheet 1 and a second sheet 2 while carrying them in the same direction to form a lamination sheet 10A; and an ultrasonic processing step for forming a welded portion 4 by carrying the lamination sheet 10A into a clearance 46 between a circumferential surface portion of an anvil roll 31 and an oscillation-applied surface 421 at a tip portion of an ultrasonic horn 42, bringing the oscillation-applied surface 421 into contact with one surface of the lamination sheet 10A, and applying ultrasonic oscillation. Immediately before carrying the lamination sheet 10A into the clearance 46, a surface in contact with the oscillation-applied surface 421 at the clearance 46 in the lamination sheet 10A is brought into contact with an edge portion 47 of a carrying-in port of the clearance 46 in the ultrasonic horn 42.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a manufacturing technique for a composite sheet in which two sheets are fused together and through-holes are formed in the fused portion. [Background technology]

[0002] As surface sheets for absorbent articles such as disposable diapers and sanitary napkins, those having irregularities formed on the surface that comes into contact with the wearer's skin are known. For example, a composite sheet is known in which a first and a second sheet are fused to each other at a number of fused parts, and the parts of the first sheet other than the fused parts form protrusions that protrude to the opposite side to the second sheet. Since such a composite sheet has irregularities formed on its surface, it is excellent in texture and in preventing the diffusion of liquid. It is also known to form through holes in the fused parts of such a composite sheet to improve the ability to draw in liquid, etc. (see Patent Documents 1 and 2). Although not a method for producing the composite sheet described above, it is known to use an ultrasonic fusion machine to bond sheets together (see Patent Documents 3 and 4).

[0003] In manufacturing a composite sheet in which a through hole is formed in a fused portion as described in Patent Documents 1 and 2, if the formation of the fused portion and the formation of the through hole are performed in separate steps, a positional deviation may occur between the position of the fused portion and the position of the through hole. In contrast, if the formation of the fused portion and the formation of the through hole can be completed in one step, such a positional deviation can be effectively suppressed. However, in a conventional method using an ultrasonic fusion machine, it is difficult to form the fused portion and the through hole in one step, and there are cases in which the through hole is not stably formed in the fused portion. In view of such defects of the conventional technology, the present applicant previously proposed a technology that uses an ultrasonic fusion machine to enable the formation of the fused portion and the formation of the through hole to be completed in one step (see Patent Documents 5 and 6). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-175688 A [Patent Document 2] JP 2006-175689 A [Patent Document 3] JP 2008-260131 A [Patent Document 4] Special Publication No. 2011-519319 [Patent Document 5] JP 2019-93467 A [Patent Document 6] JP 2019-188802 A Summary of the Invention [Problem to be solved by the invention]

[0005] The techniques described in Patent Documents 5 and 6 can complete the formation of fusion parts and the formation of through holes in one step, and can efficiently manufacture a composite sheet in which through holes are formed in the fusion parts, but there is room for improvement in terms of ease of forming through holes. For example, when the sheet material that is the material for forming the composite sheet contains a resin with a relatively high melting point (e.g., polyethylene terephthalate), if the sheet material is subjected to the formation of fusion parts and the formation of through holes simultaneously, the through holes may not be formed as designed in the treated area, and for example, the resin may remain in the area where the through holes are to be formed while maintaining the fibrous form, resulting in a through hole smaller than the designed size. There is a demand for a technique that can perform the formation of fusion parts and the formation of through holes as designed in one step regardless of the material for forming the composite sheet. In addition, it is desirable that such a technique can achieve the purpose with a relatively simple device configuration without increasing the size and complexity of the manufacturing device.

[0006] An object of the present invention is to provide a technique for forming fused parts and through holes in a single step in the production of a composite sheet having through holes formed in fused parts. [Means for solving the problem]

[0007] The present invention is a method for producing a composite sheet having a plurality of fused parts where a first sheet and a second sheet are fused, and through holes are formed in the fused parts. One embodiment of the method for producing a composite sheet of the present invention includes a layering step of layering the first sheet and the second sheet while conveying them in the same direction to form a laminated sheet. One embodiment of the method for producing a composite sheet of the present invention includes an ultrasonic treatment step in which the laminated sheet is transported into a clearance between the peripheral surface of an anvil roll and a vibration application surface at the tip of an ultrasonic horn of an ultrasonic fusion machine arranged opposite the peripheral surface, and the vibration application surface is brought into contact with one side of the laminated sheet to apply ultrasonic vibrations, thereby forming the fused portion. In one embodiment of the method for manufacturing a composite sheet of the present invention, immediately before the laminated sheet is transported into the clearance, the surface of the laminated sheet that will contact the vibration application surface in the clearance is brought into contact with the edge of the entrance of the clearance in the ultrasonic horn.

[0008] The present invention also provides an apparatus for producing a composite sheet having a plurality of fused portions where a first sheet and a second sheet are fused, with through holes formed in the fused portions. One embodiment of the composite sheet manufacturing apparatus of the present invention is equipped with an ultrasonic processing unit having an anvil roll and an ultrasonic fusion machine, the ultrasonic fusion machine including an ultrasonic horn arranged opposite the peripheral surface of the anvil roll, and a clearance is provided between the peripheral surface of the anvil roll and the vibration application surface of the tip of the ultrasonic horn through which the workpiece can be transported. One embodiment of the composite sheet manufacturing apparatus of the present invention includes a workpiece transport section that transports the first sheet and the second sheet in the same direction while stacking them to form a laminated sheet, and transports the laminated sheet, which is the workpiece, into the clearance. In one embodiment of the composite sheet manufacturing apparatus of the present invention, the ultrasonic processing unit is configured to form the fused portion by contacting the vibration application surface with one side of the laminated sheet brought into the clearance and applying ultrasonic vibrations. In one embodiment of the composite sheet manufacturing apparatus of the present invention, immediately before the laminated sheet is transported into the clearance, the surface of the laminated sheet that comes into contact with the vibration application surface in the clearance is brought into contact with the edge of the entrance of the clearance in the ultrasonic horn. Other features, advantages and embodiments of the present invention are described below. Effect of the Invention

[0009] According to the present invention, there is provided a method and apparatus for producing a composite sheet in which the formation of the fused parts and the formation of the through holes can be carried out in a single step in the production of a composite sheet having through holes formed in the fused parts. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a main portion showing one embodiment of a composite sheet produced according to the present invention. [Diagram 2] FIG. 2 is an enlarged plan view of the composite sheet shown in FIG. 1 as viewed from the first sheet side. [Diagram 3] FIG. 3 is a schematic diagram showing one embodiment of the manufacturing apparatus for the composite sheet of the present invention. [Figure 4] FIG. 4 is an enlarged perspective view showing a main part of the anvil roll (concave-convex roll) shown in FIG. [Diagram 5] FIG. 5 is a front view showing the ultrasonic welding machine shown in FIG. 3 as viewed from the upstream side in the conveying direction of the workpieces. [Figure 6] FIG. 6 is a diagram showing the tip of the ultrasonic horn and its vicinity in the manufacturing apparatus shown in FIG. [Figure 7] Figure 7(a) is a cross-sectional view along the transport direction of the workpiece, showing a schematic diagram of the state in which the workpiece is transported into the clearance between the peripheral surface of the anvil roll and the vibration application surface of the ultrasonic horn in the manufacturing apparatus shown in Figure 3, and Figure 7(b) is an enlarged view of the area surrounded by the dotted line in Figure 7(a). [Figure 8] FIG. 8 is a view equivalent to FIG. 7, but of an embodiment outside the scope of the present invention. [Figure 9]FIG. 9 is a cross-sectional view that typically shows a cross section of the tip of one embodiment of an ultrasonic horn according to the present invention, taken along the transport direction of the workpiece. [Figure 10] FIG. 10 is a view corresponding to FIG. 6 showing an embodiment of the overlapping step according to the present invention. [Figure 11] FIG. 11 is a view equivalent to FIG. 9 showing another embodiment of the ultrasonic horn according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described below based on preferred embodiments with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are basically schematic, and the ratio of each dimension may differ from the actual one.

[0012] First, a composite sheet manufactured by the composite sheet manufacturing method or manufacturing apparatus of the present invention will be described. Figures 1 and 2 show a composite sheet 10, which is one embodiment of the composite sheet. The composite sheet 10 has a plurality of fused parts 4 formed by fusing a first sheet 1 and a second sheet 2, and through holes 6 are formed in the fused parts 4.

[0013] In this embodiment, the composite sheet 10 has protrusions 5 in which at least a part of the portion of the first sheet 1 other than the fused portions 4 protrudes toward the opposite side to the second sheet 2. The protrusions 5 and the fused portions 4 are arranged alternately in a row in the X direction, which is a direction parallel to the surface of the composite sheet 10, and such rows are formed in multiple rows in the Y direction, which is a direction parallel to the surface of the composite sheet 10 and perpendicular to the one direction. The protrusions 5 and the fused portions 4 in adjacent rows are each arranged with a shift in the X direction, more specifically, with a shift of half a pitch.

[0014] In the composite sheet 10, the Y direction coincides with the flow direction of the workpiece during production (machine direction, hereinafter also referred to as "MD"), and the X direction coincides with the direction perpendicular to the MD during production (hereinafter also referred to as "CD"). The rotation axes of the first roll (anvil roll) 31 and the second roll 32 described later are parallel to the CD and perpendicular to the MD.

[0015] In this embodiment, the composite sheet 10 has a large number of recesses 3 sandwiched between protrusions 5 in both the X and Y directions on the surface facing the first sheet 1, and a fused portion 4 having a through-hole 6 is formed at the bottom of each recess 3. When viewed as a whole, the composite sheet 10 has large projections and recesses consisting of the recesses 3 and the protrusions 5 on the surface facing the first sheet 1, and the surface facing the second sheet 2 is flat or is a substantially flat surface with relatively smaller projections and recesses than the surface facing the first sheet 1.

[0016] Each fused portion 4 in the composite sheet 10 has a generally rectangular shape in plan view that is elongated in the Y direction, and has a through hole 6 that is generally rectangular in plan view formed inside each fused portion 4. In other words, each fused portion 4 is formed in a ring shape surrounding the through hole 6. It is preferable that only one through hole 6 is formed in one fused portion 4 , and that the through hole 6 is formed at a specific position that is determined in advance in relation to the position of the fused portion 4 . Furthermore, the shape of through hole 6 in plan view may or may not be similar to the shape of the outer periphery of fused portion 4 in plan view, but it is preferable that it is similar.

[0017] In the fused portion 4, the resin constituting at least one of the first sheet 1 and the second sheet 2 is melted and solidified, thereby bonding the first sheet 1 and the second sheet 2 together. When the first sheet 1 and the second sheet 2 are made of fiber sheets such as nonwoven fabric, it is preferable that the constituent fibers of the first sheet 1 and the second sheet 2 are melted or embedded in the molten resin in the fused portion 4 so that the fibrous form cannot be visually observed, that is, the fused portion 4 has a film-like appearance. In other words, the fused portion 4 is preferably in the form of a film.

[0018] The first sheet 1 and the second sheet 2 are each composed of a sheet material. Examples of the sheet material that can be used include fiber sheets such as nonwoven fabric, woven fabric, and knitted fabric; resin films, and the like, and may be a laminate of two or more of these. The types of sheet materials used for the first sheet 1 and the second sheet 2 may be the same or different.

[0019] From the viewpoint of providing a pleasant feel to the skin, it is preferable that at least one of the first sheet 1 and the second sheet 2, and preferably both, are comprised of nonwoven fabric. Here, "comprised of nonwoven fabric" includes a form in which only a portion of the sheet is made of nonwoven fabric (for example, a laminate of nonwoven fabric and a resin film) and a form in which the entire sheet is made of nonwoven fabric. The nonwoven fabric constituting both sheets 1 and 2 can be any nonwoven fabric produced by any of a variety of methods without any particular limitations. For example, an air-through nonwoven fabric, a spunbonded nonwoven fabric, a spunlace nonwoven fabric, a meltblown nonwoven fabric, a resin-bonded nonwoven fabric, a needle-punched nonwoven fabric, or a laminated nonwoven fabric obtained by laminating two or more of these nonwoven fabrics can be used.

[0020] The first sheet 1 and the second sheet 2 are typically each composed of a resin. The sheet materials such as nonwoven fabrics constituting both sheets 1 and 2 are typically mainly composed of various resins including thermoplastic resins. The constituent fibers of both sheets 1 and 2 may be single fibers made of one type of resin or a blend polymer made by mixing two or more types of resins, or may be composite fibers. The composite fiber referred to here is a synthetic fiber (e.g., thermoplastic fiber) obtained by combining two or more types of resins with different components using a spinneret and spinning them simultaneously, and the multiple components are each continuous in the length direction of the fiber and mutually bonded within the single fiber. The form of the composite fiber may be a core-sheath type, a side-by-side type, or the like, and is not particularly limited. Examples of the thermoplastic resin constituting both sheets 1 and 2 include polyolefins such as polyethylene, polypropylene, polybutene, etc., polyesters such as polyethylene terephthalate, polybutylene terephthalate, etc., polyamides such as nylon 6, nylon 66, etc., polyacrylic acid, polymethacrylic acid alkyl esters, polyvinyl chloride, polyvinylidene chloride, etc. These resins can be used alone or as a blend of two or more kinds.

[0021] However, when at least one of the first sheet 1 and the second sheet 2 contains a high-melting-point resin having a relatively high melting point, the amount of energy required to melt both sheets 1 and 2 to form the through-holes 6 increases compared to when the high-melting-point resin is not contained, and therefore it may be difficult to form the through-holes 6 by only one ultrasonic treatment step. Examples of such high-melting-point resins include resins having a melting point of more than 200°C, and a specific example is polyethylene terephthalate (PET). For example, the present invention includes a form in which one or both of the sheets 1 and 2 are composed of a nonwoven fabric, and the constituent fibers of the nonwoven fabric include a core-sheath type composite fiber having a core made of PET and a sheath made of polyethylene. In this way, when at least one of the sheets 1 and 2 is composed of PET, it may be difficult to form the through-holes 6 by only one ultrasonic treatment step. However, according to the present invention, even when the material forming the composite sheet 10 contains a high-melting-point resin such as PET, it is possible to form the fused parts 4 and the through-holes 6 by one ultrasonic treatment step due to the characteristic configuration of the present invention described later.

[0022] The basis weights of the first sheet 1 and the second sheet 2 are not particularly limited and may be appropriately set depending on the application of the composite sheet. For example, when the composite sheet is used as a component of an absorbent article (such as a top sheet), the basis weights of both sheets 1 and 2 are preferably 10 g / m 2 More preferably, 15 g / m 2 More than 40 g / m 2 Less than or equal to 35 g / m 2 The following is the result.

[0023] Next, a manufacturing method and an apparatus for manufacturing a composite sheet of the present invention will be described. Fig. 3 shows the overall configuration of a manufacturing apparatus 20 which is one embodiment of the manufacturing apparatus for a composite sheet of the present invention, and Figs. 4 to 7 show the main parts of the manufacturing apparatus 20. The manufacturing apparatus 20 is an apparatus for manufacturing the composite sheet 10 described above, and includes at least an ultrasonic processing unit 40 and a processing object transport unit 30. The ultrasonic processing unit 40 has an anvil roll 31 and an ultrasonic fusion machine 41, and the ultrasonic fusion machine 41 includes an ultrasonic horn 42 arranged opposite the peripheral portion of the anvil roll 31, and a clearance 46 through which the workpiece is transported is provided between the peripheral portion of the anvil roll 31 (specifically, the tip surface 35c of the convex portion 35 described later) and the vibration application surface 421 at the tip of the ultrasonic horn 42. Further, the workpiece transport section 30 transports the first sheet 1 and the second sheet 2 in the same direction (MD) while overlapping them to form a laminated sheet 10A, and carries the laminated sheet 10A, which is the workpiece, into the clearance 46. The laminated sheet 10A is simply a laminate of a first sheet 1 and a second sheet 2, and the sheets 1 and 2 are not fused to each other in the laminated sheet 10A.

[0024] In this embodiment, the composite sheet 10 to be manufactured has a configuration in which "at least a part of the portion other than the fused portion 4 in the first sheet 1 has a protruding portion 5 protruding on the opposite side to the second sheet 2 side," and accordingly, the anvil roll 31 is an uneven roll having unevenness on its peripheral surface. The workpiece conveying section 30 makes the first sheet 1 follow the peripheral surface of the anvil roll 31, which is an uneven roll, to deform the first sheet 1 into an uneven shape that conforms to the uneven shape of the peripheral surface, and then overlaps the second sheet 2 on the deformed first sheet 1 to form the laminated sheet 10A. Due to the unevenness forming function, the workpiece conveying section 30 can also be called an unevenness forming section.

[0025] In this embodiment, the manufacturing apparatus 20 includes, in addition to the anvil roll 31 which is a concave-convex roll, another concave-convex roll 32 having concaves and convexes on its circumferential surface which mesh with the concaves and convexes on the circumferential surface of the anvil roll 31 . Hereinafter, the anvil roll 31, which is a concave-convex roll, will also be referred to as the "first roll 31", and the other concave-convex roll 32 will also be referred to as the "second roll 32". In this embodiment, the workpiece transport section 30 uses these two rolls 31, 32, and rotates both rolls 31, 32 so that an interlocking portion 33 is formed between the uneven surfaces of the two rolls 31, 32. By introducing the first sheet 1 into the interlocking portion 33, the first sheet 1 is deformed into an uneven shape that conforms to the uneven shape of the peripheral surface of the first roll 31.

[0026] 4 shows a part of the peripheral surface of the first roll 31. The first roll 31 is formed into a roll shape by combining a plurality of spur gears 31a, 31b, ... each having a predetermined tooth width. The teeth of each gear form a convex portion 35 having an uneven shape on the peripheral surface of the first roll 31, and a tip surface 35c of the convex portion 35 serves as a pressure surface for pressing the first and second sheets 1 and 2 (laminate sheet 10A) to be fused together with a vibration application surface 421, which is a tip surface of an ultrasonic horn 42 of an ultrasonic fusion machine 41 described later.

[0027] The tooth width (the axial length of the gear) of each gear that constitutes the first roll 31 determines the X-direction dimension of the protrusions 5 of the composite sheet 10, and the tooth length (the rotational length of the gear) of each gear determines the Y-direction dimension of the protrusions 5 of the composite sheet 10. Adjacent gears are assembled such that the tooth pitches of the gears are shifted by half a pitch, resulting in the first roll 31 having an uneven circumferential surface. In the illustrated form, the tip surface 35c of each convex portion 35 has a rectangular shape having a long side along the rotation direction of the first roll 31 (the gear) and a short side along the rotation axis direction of the first roll 31 (the gear). It is preferable that the tip surface 35c has a shape that is longer in the direction of rotation, since this makes it easier to increase the temperature by lengthening the contact time between each protrusion 35 of the first roll 31 and the vibration application surface 421 of the tip of the ultrasonic horn 42.

[0028] The recesses of each gear in the first roll 31 form concave portions of the unevenness on the peripheral surface of the first roll 31 . A suction hole 34 is formed in the tooth bottom (bottom of the recess) of each gear. The suction hole 34 is connected to a suction source (not shown) such as a blower or a vacuum pump, and is controlled so that suction is performed from the meshing portion 33 between the first roll 31 and the second roll 32 to the joining portion of the first sheet 1 and the second sheet 2. Therefore, the first sheet 1, which has been deformed into an uneven shape by the meshing of the first roll 31 and the second roll 32, is maintained in a deformed state into a shape that conforms to the unevenness of the peripheral surface of the first roll 31 by the suction force of the suction holes 34, and is transported to the confluence of the first sheet 1 and the second sheet 2 and to the ultrasonic vibration application section 36 by the ultrasonic fusion machine 41. In the first roll 31 shown in Figure 4, a predetermined gap G is provided between adjacent gears, which prevents the first sheet 1 from being subjected to excessive stretching force or from being cut at the meshing portion 33 of the two rolls 31, 32, and makes it easier for the first sheet 1 to deform into an uneven shape that conforms to the shape of the peripheral surface of the first roll 31.

[0029] The second roll 32, which is an uneven roll, has an uneven shape on its peripheral surface that meshes with the unevenness of the peripheral surface of the first roll 31. The second roll 32 has the same configuration as the first roll 31, except that it does not have suction holes 34. The diameter of the first roll 31 and the diameter of the second roll 32 may be different, provided that the concave and convex portions of both rolls 31, 32 mesh with each other. The first sheet 1 can be deformed into an uneven shape by introducing the first sheet 1 into the meshing portion 33 of both rolls 31, 32 while rotating both rolls 31, 32 having meshing concave and convex portions. At the interlocking portion 33, multiple points of the first sheet 1 are pressed into the recesses on the peripheral surface of the first roll 31 by the convex portions of the second roll 32, and the pressed-in portions become the convex portions 5 of the composite sheet 10 to be manufactured. The peripheral surface of the second roll 32 is formed with a plurality of protrusions that are inserted into the recesses of the first roll 31, but it is not essential that the second roll 32 has protrusions that correspond to all of the recesses of the first roll 31.

[0030] As described above, the workpiece conveying section 30 shown in FIG. 3 includes two uneven rolls having unevenness on the peripheral surface, and the two uneven rolls 31, 32 are rotated so that the unevenness of the two rolls 31, 32 is interlocked with each other at an interlocking portion 33, and the first sheet 1 is introduced into the interlocking portion 33 to deform the first sheet 1 into an uneven shape. However, the uneven roll included in the workpiece conveying section 30 may be only the first roll 31 capable of sucking the first sheet 1 introduced into the peripheral portion, that is, the second roll 32 may not be included. In that case, by simply introducing the first sheet 1 into the peripheral portion of the first roll 31, the first sheet 1 is deformed to follow the uneven shape of the peripheral portion by the suction force of the suction holes 34 (see FIG. 4) arranged on the peripheral portion. Such following and deformation of the first sheet 1 by suction at the peripheral portion of the first roll 31 can be realized by appropriately adjusting the suction force and the arrangement of the suction holes 34.

[0031] The ultrasonic processing unit 40 is equipped with an ultrasonic fusion machine 41 equipped with an ultrasonic horn 42, and a second sheet 2 is superimposed on the first sheet 1 in a state in which it has been deformed into an uneven shape to obtain a laminated sheet 10A. The laminated sheet 10A is then transported into a clearance 46 between the peripheral portion of the first roll 31 and the vibration application surface 421 at the tip of the ultrasonic horn 42, and ultrasonic vibration is applied while the laminated sheet 10A is sandwiched between the peripheral portion (specifically, the convex portion 35) and the vibration application surface 421, thereby forming a through hole 6 and forming a fused portion 4 having the through hole 6.

[0032] As shown in FIGS. 3 and 5, the ultrasonic fusion machine 41 includes an ultrasonic oscillator (not shown), a converter 43, a booster 44, and an ultrasonic horn . An ultrasonic oscillator (not shown) is electrically connected to the converter 43 , and a high-voltage electrical signal with a frequency of about 15 to 50 kHz generated by the ultrasonic oscillator is input to the converter 43 . An ultrasonic oscillator (not shown) is installed on the movable base 45 or outside the movable base 45 .

[0033] The converter 43 has a built-in piezoelectric element such as a piezoelectric element, and converts an electrical signal input from an ultrasonic oscillator into mechanical vibration by the piezoelectric element. The booster 44 adjusts, preferably amplifies, the amplitude of the mechanical vibration emitted from the converter 43 and transmits it to the ultrasonic horn 42. The ultrasonic horn 42 is made of a block of metal such as an aluminum alloy or titanium alloy, and is designed to resonate correctly at the frequency to be used. The ultrasonic vibration transmitted from the booster 44 to the ultrasonic horn 42 is also amplified or attenuated inside the ultrasonic horn 42, and is applied to the objects to be fused, that is, the first and second sheets 1 and 2. As such an ultrasonic fusion machine 41, a commercially available ultrasonic horn, converter, booster, and ultrasonic oscillator can be combined and used.

[0034] The ultrasonic fusion machine 41 is fixed on a movable table 45, and by moving the position of the movable table 45 back and forth in a direction approaching the peripheral surface of the first roll 31, the height of the clearance 46 (the distance between the peripheral surface of the first roll 31 and the vibration application surface 421 of the ultrasonic horn 42) and the pressure applied to the workpiece brought into the clearance 46 can be adjusted. Then, the laminated sheet 10A to be fused is brought into the clearance 46, and pressure is applied between the peripheral surface (tip surface 35c of convex portion 35) of the first roll 31 that defines the clearance 46 and the vibration application surface 421 of the ultrasonic horn 42 while ultrasonic vibration is applied from the vibration application surface 421. As a result, the portion of the laminated sheet 10A located on the tip surface 35c of the convex portion 35 heats up, and the first sheet 1 and / or the second sheet 2 that constitute the laminated sheet 10A melts and solidifies again, forming a fused portion 4 and forming a through hole 6 that penetrates both sheets 1, 2 in a state surrounded by the molten portion.

[0035] The vibration application surface 421 at the tip of the ultrasonic horn 42 consists of the tip surface of the main body 420 of the ultrasonic horn 42 made of a metal such as an aluminum alloy or a titanium alloy, and abuts against the workpiece, more specifically, the second sheet 2 that constitutes one side of the laminated sheet 10A (the side opposite to the contact surface with the peripheral surface of the first roll 31). As shown in Figures 5 and 6, the main body 420 of the ultrasonic horn 42 has a vibration application surface 421 which is its tip surface, and a number of surfaces 422 to 424 which are connected to the vibration application surface 421 and intersect (orthogonal to) the vibration application surface 421. In this embodiment, the vibration application surface 421 has a rectangular shape in which the length of the CD is longer than the length of the MD in a plan view, and the main body 420 has a pair of faces 422, 423 connected to a pair of long sides along the CD of the vibration application surface 421 of the rectangular shape in a plan view, and a pair of side faces 424, 424 connected to a pair of short sides along the MD of the vibration application surface 421. The front face 422 of the main body 420 is located on the upstream side of the MD and is adjacent to the carry-in entrance of the clearance 46. The carry-in entrance of the clearance 46 is an opening on the upstream side of the MD in the clearance 46, and is an entrance for the workpiece (laminated sheet 10A). The back face 423 of the main body 420 is located on the downstream side of the MD and is adjacent to the carry-out exit of the clearance 46.

[0036] As shown in Fig. 6, the ultrasonic processing unit 40 is adapted to apply ultrasonic vibrations by contacting the vibration application surface 421 with one surface (the second sheet 2 in this embodiment) of the laminated sheet 10A carried into the clearance 46, thereby forming the fused portion 4. As shown in Fig. 7, the manufacturing apparatus 20 is characterized in that, immediately before carrying the laminated sheet 10A into the clearance 46, the surface of the laminated sheet 10A that contacts the vibration application surface 421 in the clearance 46 (the second sheet 2 in this embodiment) is brought into contact with the entrance edge 47 of the clearance 46 of the ultrasonic horn 42. The entrance edge 47 of the ultrasonic horn 42 is the tip of the main body 420 and its vicinity on the front surface 422 of the main body 420 of the ultrasonic horn 42, and extends along the entrance of the clearance 46 in the CD. 7 indicates the contour line of the peripheral surface of the first roll 31, and in this embodiment, is an imaginary line that passes through the tips of the multiple protrusions 35 on the peripheral surface of the first roll 31 and extends in the circumferential direction.

[0037] The above-mentioned "contact of the laminated sheet 10A with the inlet edge 47 of the ultrasonic horn 42 immediately before the laminated sheet 10A is carried into the clearance 46" is intentional. The "intentional contact" here means preventing the laminated sheet 10A from contacting the inlet edge 47 of the ultrasonic horn 42 immediately before the laminated sheet 10A is carried into the clearance 46 due to unintended thickness variation of the laminated sheet 10A. In this way, by intentionally bringing laminate sheet 10A into contact with inlet edge 47 of ultrasonic horn 42 immediately before being carried into clearance 46, a large shear force acts on laminate sheet 10A, and as a result, through holes 6 are formed in laminate sheet 10A before being carried into clearance 46, or even if through holes 6 are not formed, the strength of laminate sheet 10A is reduced mainly around the contact portion with inlet edge 47, making it easier to form through holes 6 in clearance 46 thereafter. Therefore, according to manufacturing apparatus 20, in manufacturing composite sheet 10 having through holes 6 formed in fused portions 4, it is possible to form fused portions 4 and through holes 6 in a single process.

[0038] In this embodiment, as shown in FIG. 7, the distance L between the peripheral surface of the first roll 31 and the vibration application surface 421 at the inlet of the clearance 46, i.e., the height L of the inlet of the clearance 46, is made shorter than the thickness T of the workpiece (laminated sheet 10A) just before it is brought into the inlet. Note that the "thickness T" here refers to the maximum thickness when the thickness of the workpiece is not constant, and refers to the apparent thickness (the distance between one side and the other side of the workpiece) rather than the actual thickness (the thickness of the part where the forming material such as fibers exists). In this way, the magnitude relationship of "height L of the inlet of the clearance 46 < thickness T of the workpiece just before it is brought into the inlet" is established, so that the ultrasonic horn 42 can contact the inlet edge 47 just before the workpiece (laminated sheet 10A) is brought into the clearance 46, as described above, and it becomes easier to form the fusion part 4 and the through hole 6 in one process.

[0039] According to the findings of the inventors, the greater the difference between the height L and the thickness T, the greater the change in thickness of the laminated sheet 10A before and after it is brought into the clearance 46, and accordingly the frictional force acting on the laminated sheet 10A increases, making it easier to form the through holes 6. The ratio of the height L to the thickness T, assuming that the height L is less than the thickness T, is preferably 0.0125 or more, more preferably 0.025 or more, and is preferably 0.5 or less, more preferably 0.125 or less, as expressed by height L / thickness T. The height L of the inlet of clearance 46 is preferably 0.01 mm or more, more preferably 0.02 mm or more, and preferably 0.4 mm or less, more preferably 0.1 mm or less, provided that this is shorter than the thickness T of the workpiece (laminated sheet 10A) immediately before it is brought into the inlet.

[0040] In this embodiment, in order to establish the magnitude relationship of "height L<thickness T" described above, the positional relationship between the ultrasonic horn 42 and the first roll 31 is adjusted. Specifically, as shown in Fig. 8, when a center 421C of MD of the vibration application surface 421 of the ultrasonic horn 42 is located on a virtual straight line 31L passing through the rotation center of the first roll 31 and extending in the radial direction of the first roll 31, and the position of the center 421C is set as a reference position RP, in this embodiment, the ultrasonic horn 42 is disposed so that the center 421C is located downstream of the reference position RP in MD as shown in Fig. 7. In this type of fusion device, from the viewpoint of smoothly transporting the workpiece into the clearance, it is common to either align the center 421C of the MD of the vibration application surface 421 with the reference position RP as shown in FIG. 8, or, conversely to FIG. 7, position the center 421C upstream of the reference position RP in the MD. In this way, as shown in FIG. 8(b), the workpiece, that is, the laminated sheet 10A, is smoothly transported into the clearance 46 from the inlet without coming into contact with the inlet edge 47 of the ultrasonic horn 42. In contrast, in this embodiment, priority is given to facilitating the formation of the through-holes 6, and for that purpose, in order to ensure that the above-mentioned magnitude relationship of "height L<thickness T" is established, the center 421C of the MD of the vibration application surface 421 is shifted downstream of the MD from the reference position RP, contrary to the above-mentioned general method. The distance G1 (see FIG. 7(a)) between the reference position RP and the center 421C of the MD of the vibration application surface 421 may be adjusted so that the above-mentioned magnitude relationship (height L<thickness T) is established, taking into consideration the overall length of the MD of the vibration application surface 421, the radius of the first roll 31, etc.

[0041] As a method for establishing the magnitude relationship of "height L<thickness T", in addition to the method of adjusting the position of ultrasonic horn 42, for example, a method of adjusting the shape of vibration application surface 421 of ultrasonic horn 42 can be mentioned. Specifically, as in ultrasonic horn 42A shown in Fig. 9, when viewed in cross section along MD (viewed in cross section along a direction perpendicular to the rotation axis of first roll 31), it is preferable that vibration application surface 421 has a shape that follows the contour line (imaginary line extending in the circumferential direction through the tips of multiple convex portions 35 of first roll 31) 31S of the peripheral surface of first roll 31, because this makes it easier to establish the magnitude relationship.

[0042] As shown in Figures 6 and 7, when the vibration application surface 421 at the tip of the ultrasonic horn 42 faces the tip surface 35c of the convex portion 35 that constitutes the unevenness of the peripheral surface of the first roll 31, which is a concave-convex roll, and a clearance 46 is provided between the vibration application surface 421 and the tip surface 35c of the convex portion 35 (hereinafter, this state is also referred to as "state A"), the distance between the vibration application surface 421 and the tip surface 35c of the convex portion 35 (the height of the clearance 46) changes due to the movement of the convex portion 35 associated with the rotation of the first roll 31. In the state A, when the convex portion 35 is located upstream of a virtual perpendicular line (not shown) that passes through the center of rotation of the first roll 31, extends in the radial direction of the first roll 31, and is perpendicular to the vibration application surface 421, in the rotation direction (MD) of the first roll 31, the distance (height of the clearance 46) between the vibration application surface 421 and the tip surface 35c of the convex portion 35 gradually decreases from the upstream side to the downstream side in the rotation direction (MD). Furthermore, in state A, when the convex portion 35 overlaps with the virtual perpendicular line, the distance between the vibration application surface 421 and the tip surface 35c of the convex portion 35 (the height of the clearance 46) gradually decreases from the entrance of the clearance 46 toward the virtual perpendicular line, becomes minimum at the position of the virtual perpendicular line, and gradually increases from the virtual perpendicular line toward the exit of the clearance 46. Furthermore, in state A, when the convex portion 35 is located downstream of the virtual perpendicular line in the rotation direction (MD) of the first roll 31, the distance between the vibration application surface 421 and the tip surface 35c of the convex portion 35 (height of the clearance 46) gradually increases from the upstream side to the downstream side in the rotation direction (MD).

[0043] 9, in a cross-sectional view along the MD, the contour line 31S of the peripheral surface of the first roll 31 is arc-shaped, so that in the cross-sectional view along the MD, the vibration application surface 421 has an arc-shaped shape recessed in a direction away from the rotation axis of the first roll 31, and the vibration application surface 421 and the contour line 31S are parallel to each other. When the cross-sectional shape along the MD of the vibration application surface 421 is arc-shaped in this way, the shear force applied to the laminated sheet 10A, which is the object to be treated, is improved in the ultrasonic treatment process described later, so that the fused portions 4 and the through-holes 6 can be formed simultaneously more reliably. In addition, when the vibration application surface 421 has an arc shape in a cross-sectional view along the MD as shown in Figure 9, it is preferable that the tip surface 35c of each of the multiple convex portions 35 of the first roll 31 corresponding to this has a convex shape facing away from the rotation axis of the first roll 31 in the same cross-sectional view, and that the direction of curvature coincides with that of the vibration application surface 421. The radius of curvature of the vibration application surface 421 of the ultrasonic horn 42A is preferably 100% or more of the radius of curvature of the tip surface 35c of the protrusion 35 of the first roll 31. Moreover, the radius of curvature of the vibration application surface 421 is preferably 500% or less, and more preferably 200% or less.

[0044] Methods for achieving the above-mentioned "height L<thickness T" relationship include, in addition to adjusting the position of the ultrasonic horn 42 and the shape of the vibration application surface 421, making the MD length L1 (see Figure 6) of the vibration application surface 421 relatively short, and making the diameter 31R (see Figure 3) of the first roll 31 relatively long. The length L1 of the MD of the vibration application surface 421 is preferably 2.5 mm or more, more preferably 3.5 mm or more, and is preferably 16 mm or less, more preferably 8 mm or less. The diameter 31R of the first roll 31 is preferably 40 mm or more, more preferably 160 mm or more, and is preferably 1600 mm or less, more preferably 800 mm or less.

[0045] In this embodiment, the manufacturing apparatus 20 includes a preheating means 51 for preheating at least one of the first sheet 1 and the second sheet 2 before application of ultrasonic vibrations thereto. The preheating means 51 is disposed inside the first roll 31 and extends parallel to the rotation axis (CD) of the first roll 31 . A plurality of preheating means 51 are arranged around the rotation axis of first roll 31 in the vicinity of the outer periphery at intervals in the circumferential direction. The preheating means 51 can be anything that can heat the object to be heated (first sheet 1, second sheet 2) by applying thermal energy from the outside, such as a cartridge heater that uses an electric heating wire, but is not limited to this, and various known heating means can be used without any particular restrictions.

[0046] The preheating means 51 is a part of the preheating mechanism 50. In addition to the preheating means 51, the preheating mechanism 50 includes a temperature measuring means (not shown) capable of measuring the temperature of the workpiece before the application of ultrasonic vibrations, and a temperature control section (not shown) that controls the temperature of the preheating means 51 based on the measured value of the temperature measuring means. The heating temperature of the peripheral surface of the first roll 31 by the preheating means 51 is controlled by the temperature control section. The preheating mechanism 50 makes it possible to maintain the temperature of the first sheet 1 conveyed into the ultrasonic vibration application section 36 within a predetermined range while the manufacturing apparatus 20 is in operation.

[0047] 6, the manufacturing apparatus 20 includes a horn heating means 61 for heating the ultrasonic horn 42 including the vibration application surface 421. As the horn heating means 61, various known heating means such as a heater can be used without any particular limitation. The position of the horn heating means 61 is not particularly limited as long as it is a position where vibration application surface 421 can be heated, but it is typically arranged on one or more of the multiple surfaces 422 to 424 of the main body 420 of the ultrasonic horn 42 that are connected to and intersect with vibration application surface 421. In this embodiment, the horn heating means 61 is arranged on the back surface 423 of the main body 420.

[0048] Horn heating means 61 is a part of horn heating mechanism 60. In addition to horn heating means 61, horn heating mechanism 60 includes temperature measuring means (not shown) capable of measuring the temperature of vibration application surface 421, and a temperature control section (not shown) that controls the temperature of horn heating means 61 based on the measured value of the temperature measuring means. The heating temperature of vibration application surface 421 by horn heating means 61 is controlled by the temperature control section. By means of horn heating mechanism 60, the temperature of vibration application surface 421 can be maintained within a predetermined range while manufacturing apparatus 20 is in operation.

[0049] The ultrasonic fusion machine 41 applies ultrasonic vibrations to the workpieces, thereby generating heat and melting the workpieces to fuse them, and is clearly distinguished from the preheating means 51 and horn heating means 61 described above.

[0050] The manufacturing method of the composite sheet 10 using the manufacturing apparatus 20 having the above-mentioned configuration includes a lamination step of laminating the first sheet 1 and the second sheet 2 while conveying them in the same direction to form the laminated sheet 10A, as shown in Fig. 3. The manufacturing method also includes an ultrasonic processing step of conveying the laminated sheet 10A into a clearance 46 between the peripheral surface of the first roll 31 and a vibration application surface 421 at the tip of an ultrasonic horn 42 of an ultrasonic fusion machine 41 arranged opposite the peripheral surface, and contacting the vibration application surface 421 with one surface (second sheet 2) of the laminated sheet 10A to apply ultrasonic vibrations, thereby forming the fused portion 4.

[0051] As described above, in this embodiment, an uneven roll having unevenness on its peripheral surface is used as the first roll 31, and in the overlapping process, while the first roll 31, which is an uneven roll, is rotated, the first sheet 1 is made to follow the peripheral surface of the first roll 31 and deformed into an uneven shape, and the deformed first sheet 1 is transported while being held on the peripheral surface of the first roll 31, and the second sheet 2 is overlapped on the first sheet 1 during transport to form the laminated sheet 10A. Furthermore, as described above, in this embodiment, in addition to the first roll 31 which is an uneven roll, a second roll 32 which is another uneven roll having unevenness on its peripheral surface which meshes with the unevenness on the peripheral surface of the first roll 31 is used, and in the overlapping process, both rolls 31, 32 are rotated so that an interlocking portion 33 is formed between the unevennesses of both rolls 31, 32, and the first sheet 1 is introduced into the interlocking portion 33, thereby deforming the first sheet 1 into an uneven shape.

[0052] The manufacturing method of the composite sheet 10 is characterized in that immediately before the laminated sheet 10A, which is the object to be processed, is carried into the clearance 46 between the peripheral surface of the first roll 31 and the vibration application surface 421 of the ultrasonic horn 42, a surface of the laminated sheet 10A that will come into contact with the vibration application surface 421 in the clearance 46 (the second sheet 2 in this embodiment) is brought into contact with an entrance edge 47 of the clearance 46 in the ultrasonic horn 42. Due to this feature, this manufacturing method makes it possible to form the fused portions 4 and the through holes 6 in a single step.

[0053] According to the manufacturing method of the composite sheet 10, the through holes 6 can be formed in the laminate sheet 10A by contacting the ultrasonic horn 42 of the laminate sheet 10A with the entrance edge 47 of the clearance 46 immediately before the laminate sheet 10A is carried into the clearance 46. In this case, the through holes 6 are first formed in the laminate sheet 10A before the laminate sheet 10A is carried into the clearance 46, and then ultrasonic vibration is applied to the laminate sheet 10A after the laminate sheet 10A is carried into the clearance 46, forming the fused portion 4, thereby forming the composite sheet 10. In order to ensure the formation of the through holes 6 before the laminate sheet 10A is carried into the clearance 46, it is effective to establish the above-mentioned magnitude relationship "height L of the entrance of the clearance 46 < thickness T of the workpiece immediately before the workpiece is carried into the entrance", and the device for achieving this has been described above.

[0054] In addition, from the viewpoint of making it possible to reliably form the fused portion 4 and the through-hole 6 in one step by fully utilizing the characteristic configuration of the present invention described above, in the overlapping step, it is preferable to convey the first sheet 1 while holding it on the peripheral surface of the first roll 31, to overlap the second sheet 2 on the first sheet 1 being conveyed to form a laminated sheet 10A, and to convey the laminated sheet 10A while holding it on the peripheral surface of the first roll 31 and convey it into the clearance 46, as shown in Fig. 10. That is, in the embodiment shown in Fig. 6, the first sheet 1 and the second sheet 2 are overlapped at substantially the same position as the inlet of the clearance 46 to form the laminated sheet 10A, and the moving distance of the laminated sheet 10A to the inlet is substantially zero, but instead, it is preferable to overlap both sheets 1 and 2 at a position some distance away from the inlet of the clearance 46 on the upstream side of the MD to form the laminated sheet 10A, as shown in Fig. 10, and to convey the formed laminated sheet 10A a certain distance before conveying it into the clearance 46. The distance from the clearance 46 to the position where the first sheet 1 and the second sheet 2 are superposed is preferably 3 mm or more, more preferably 10 mm or more, and preferably 50 mm or less, more preferably 30 mm or less. If the distance is within the above range, as described above, it is sufficiently possible to bring the surface of the laminated sheet 10A that contacts the vibration application surface 421 in the clearance 46 into contact with the entrance edge 47 of the clearance 46 of the ultrasonic horn 42 immediately before the laminated sheet 10A is carried into the clearance 46. The "distance" here means the distance along the carrying path of the object (laminated sheet 10A), and for example, as shown in FIG. 10, when the carrying path of the laminated sheet 10A is along the arc-shaped peripheral surface of the first roll 31, it means the distance along the peripheral surface.

[0055] In the ultrasonic treatment process, the pressure applied to the first and second sheets 1, 2 by sandwiching them between the tip surface 35c of the convex portion 35 of the first roll 31 and the vibration application surface 421 of the ultrasonic horn 42 is preferably 10 N / mm or more, and more preferably 15 N / mm or more, from the viewpoint of ease of forming the fused portion 4 and the through holes 6. The pressure is preferably 30 N / mm or less, and more preferably 25 N / mm or less. The "pressure" referred to here is the so-called linear pressure, and is expressed as the pressure (N) of the ultrasonic horn 42 divided by the total length (excluding the recesses of the first roll 31) of the tooth widths (lengths along the CD of the protrusions 35) of the protrusions 35 that are in contact with the ultrasonic horn 42 (pressure per unit length).

[0056] From the same viewpoint, the frequency of the applied ultrasonic vibration is preferably 15 kHz or more, and more preferably 20 kHz or more. The frequency is preferably 50 kHz or less, and more preferably 40 kHz or less. From the same viewpoint, the amplitude of the applied ultrasonic vibration is preferably 20 μm or more, and more preferably 25 μm or more. The amplitude is preferably 50 μm or less, and more preferably 40 μm or less. When measuring the frequency and amplitude of ultrasonic vibration, the displacement of the tip of the ultrasonic horn is measured using a laser displacement meter or the like, and the frequency and amplitude are measured at a sampling rate of 200 kHz or higher and an accuracy of 1 μm or higher.

[0057] As described above, in this embodiment, the manufacturing apparatus 20 is equipped with a preheating means 51 (preheating mechanism 50), and in the manufacturing method of the composite sheet 10 using the manufacturing apparatus 20, at least one of the first sheet 1 and the second sheet 2 is preheated by the preheating means 51 before being subjected to the ultrasonic treatment step, which, combined with the action and effect of the characteristic configuration of the present invention described above (intentionally bringing the workpiece into contact with the inlet edge 47 of the ultrasonic horn 42 immediately before being carried into the clearance 46), makes it possible to more reliably simultaneously form the fused portion 4 and the through hole 6. However, the manufacturing apparatus 20 does not have to be equipped with the preheating means 51 (preheating mechanism 50).

[0058] The conditions for preheating the workpiece by the preheating means 51 are not particularly limited and may be adjusted appropriately depending on the type of the workpiece, but it is preferable to heat at least one of the first sheet 1 and the second sheet 2 to a temperature lower than the melting point of the sheet or equal to or higher than 50° C. lower than the melting point. That is, prior to the application of ultrasonic vibrations, it is preferable to carry out either or both of the following (1) and (2). (1) The first sheet 1 is heated to a temperature lower than the melting point of the first sheet, but not lower than 50° C. below the melting point. (2) The second sheet 2 is heated to a temperature lower than the melting point of the second sheet, but not lower than 50° C. below the melting point. Preferably, the first sheet 1 is heated to a temperature that is less than the melting point of the first sheet and is 50°C lower than the melting point, and the second sheet 2 is heated to a temperature that is less than the melting point of the second sheet and is 50°C lower than the melting point.

[0059] As for the method (1) above, i.e., a method of heating the first sheet 1 to a temperature lower than the melting point of the first sheet 1 and at least 50°C lower than the melting point, for example, the temperature of the first sheet 1 on the first roll 31 is measured between the meshing portion 33 of the first roll 31 and the second roll 32 and the application portion 36 of the ultrasonic vibration by the ultrasonic fusion machine 41, and the temperature of the preheating means 51 is controlled so that the measured value falls within the specific range mentioned above. As a method of preheating the first sheet 1 to a specific temperature range, various methods can be used instead of a method of controlling the temperature of the peripheral portion of the first roll 31 by a heater disposed within the first roll 31 so that the first sheet 1 has a temperature within a specific range. For example, a method may be used in which a heater, a hot air outlet, or a far-infrared ray irradiation device is provided near the peripheral portion of the first roll 31, and the temperature of the peripheral portion of the first roll 31 is controlled using these devices before or after the first sheet 1 is aligned; or a method may be used in which the second roll 32, which contacts the first sheet 1 at the meshing portion 33, is heated, and the temperature of the first sheet 1 is controlled by controlling the temperature of its peripheral portion. Further, there may be mentioned a method in which the first sheet 1 before being aligned around the first roll 31 is brought into contact with a heated roller, passed through a space maintained at a high temperature, or is blown with hot air.

[0060] As for the method (2) above, i.e., a method for heating the second sheet 2 to a temperature lower than the melting point of the second sheet 2 and at least 50°C lower than the melting point, it is preferable to measure the temperature of the second sheet 2 before it is merged with the first sheet 1 with a temperature measuring means arranged in the conveying path of the second sheet 2, and to control the temperature of a heating means (not shown) for the second sheet 2 arranged in the conveying path of the second sheet 2 so that the measured value falls within the specific range described above. The means for heating the second sheet 2 may be a contact type, such as contacting it with a heated roller or the like, or a non-contact type, such as passing it through a space maintained at a high temperature, blowing hot air onto it or passing it through, or irradiating it with infrared rays.

[0061] The melting points of the first sheet 1 and the second sheet 2 can be measured, for example, using a differential scanning calorimeter (DSC) PYRIS Diamond DSC manufactured by Perkin-Elmer, Inc. In such a measurement method, the melting points of the measurement objects (first sheet 1, second sheet 2) are calculated from the peak value of the measurement data. When the first sheet 1 or the second sheet 2 is a fiber sheet such as a nonwoven fabric, and the constituent fibers are composite fibers consisting of multiple components such as core-sheath type or side-by-side type, the melting point of the sheet is the lowest melting point among the multiple melting points measured by DSC, and is defined as the melting point of the composite fiber sheet.

[0062] As described above, in this embodiment, the manufacturing apparatus 20 is equipped with the horn heating means 61 (horn heating mechanism 60), and in the ultrasonic processing step, ultrasonic vibration is applied to the workpiece (laminated sheet 10A) using the vibration application surface 421 heated by the horn heating means 61 and the peripheral surface of the first roll 31, so that, in combination with the action and effect of the characteristic configuration of the present invention described above (the workpiece is intentionally brought into contact with the inlet edge 47 of the ultrasonic horn 42 just before being carried into the clearance 46), the fusion portion 4 and the through hole 6 can be formed simultaneously more reliably. However, the manufacturing apparatus 20 does not have to be equipped with the horn heating means 61 (horn heating mechanism 60).

[0063] The conditions for heating by the horn heating means 61 are not particularly limited, and may be appropriately adjusted depending on the type of the workpiece, etc. For example, the method (2) may be carried out by using a horn heating means 61 instead of the preheating means 51. That is, by controlling the temperature of the ultrasonic horn 42 (vibration application surface 421) heated by the horn heating means 61, the temperature of the second sheet 2 immediately before the application of ultrasonic vibrations may be heated to a temperature lower than the melting point of the second sheet 2 or equal to or higher than the melting point by 50° C., and ultrasonic vibrations may be applied to the first and second sheets 1, 2 sandwiched between the convex portions 35 of the concave-convex roll 331 and the vibration application surface 421 in this state. Moreover, either one of the preheating means 51 or the horn heating means 61 may be used, or both may be used in combination.

[0064] Another embodiment of the present invention is shown in Fig. 11. In the other embodiment described below, components different from the above embodiment will be mainly described, and similar components will be given the same reference numerals and description will be omitted. For components that are not particularly described, the description of the above embodiment will be applied as appropriate.

[0065] 11, the tip of ultrasonic horn 42B includes heat storage section 425 fixed to metallic main body section 420 of ultrasonic horn 42B, and vibration application surface 421 is formed from heat storage section 425. Heat storage section 425 is made of a heat storage material having a lower thermal conductivity than the metal constituting main body section 420. When the vibration application surface 421 is formed from the heat storage section 425, the heat of the first and second sheets 1, 2 generated by the ultrasonic vibration is stored in the heat storage section 425, and as a result, the temperature of the heat storage section 425 rises and the first sheet 1 and the second sheet 2 can be heated, which, in combination with the action and effect of the characteristic configuration of the present invention described above (intentionally bringing the workpiece into contact with the inlet edge section 47 of the ultrasonic horn 42 immediately before being carried into the clearance 46), makes it possible to more reliably form the fusion section 4 and the through hole 6 simultaneously. In addition, when the vibration application surface 421 is formed from the heat storage section 425, the occurrence of inconveniences such as adhesion of the molten resin to the conveying means caused by the melting of the first and second sheets 1, 2 and wrapping of the sheets around the conveying roll is suppressed, and there is an advantage in that the maintenance burden of the manufacturing apparatus is reduced. The vibration application surface 421 consisting of the heat storage section 425 shown in FIG. 11 has an arc shape when viewed in cross section along the MD, similar to the vibration application surface 421 of the ultrasonic horn 42A shown in FIG. 9, but may have a straight line shape (for example, a straight line extending in the tangent direction of the first roll 31) instead of an arc shape when viewed in the same cross section.

[0066] The thermal conductivity of the heat storage material constituting the heat storage section 425 is preferably 2.0 W / mK or less, and more preferably 1.0 W / mK or less, from the viewpoint of making it difficult for heat to be dissipated to the ultrasonic horn 42 or the atmosphere. From the viewpoint of efficiently heating the sheet, the thermal conductivity of the heat storage material is preferably 0.1 W / mK or more, and more preferably 0.5 W / mK or more. The thermal conductivity of the heat storage material can be measured by a conventional method using a thermal conductivity measuring device. The thickness Th (see FIG. 11) of the heat storage section 425 is not particularly limited, but is preferably 5 μm or more, and more preferably 10 μm or more, from the viewpoint of ensuring the effect of the heat storage section 425. Moreover, the thickness Th is preferably 100 μm or less, and more preferably 50 μm or less.

[0067] As the heat storage material constituting the heat storage section 425, it is preferable to use a synthetic resin having excellent wear resistance and heat resistance, provided that the thermal conductivity is lower than that of the metal constituting the main body section 420. Examples of the synthetic resin include synthetic resins such as polyimide, polybenzimidazole, polyether ethyl ketone, polyether ether ketone (PEEK), polyphenylene sulfite, polyetherimide, and polyamide imide, which have a Rockwell hardness of R120 or more and R140 or less and a heat resistance temperature of 150°C or more and 500°C or less. As the heat storage material, a synthetic resin having a Rockwell hardness of R125 or more and R140 or less and a heat-resistant temperature of 280° C. or more and 400° C. or less, such as polyimide or polybenzimidazole, is particularly preferable. Here, the Rockwell hardness is a value measured in accordance with ASTM D-785, and the heat resistance temperature is a value measured in accordance with ASTM D-648.

[0068] The means for fixing the synthetic resin heat storage unit 425 to the metal body 420 is not particularly limited, and known fixing means can be used. The synthetic resin heat storage unit 425 can be formed on the metal body 420 by thermal spraying, for example, and fixed to the metal body 420. The term "thermal spraying" used here refers to a known surface treatment method in which particles of a thermal spray material such as metal or ceramics that has been heated to a molten or nearly molten state are accelerated and collided at high speed with a substrate surface to form a coating on the substrate surface. As the thermal spray material, any material that can be thermally sprayed and can contribute to improving the fixing strength of the synthetic resin heat storage unit 425 can be used without particular limitation, but from the viewpoint of excellent bonding strength to the main body 420 made of a metal such as a titanium alloy, and excellent wear resistance and heat resistance, ceramics such as tungsten carbide, zirconia, and chromium carbide, alloys such as aluminum magnesium, zinc aluminum, metals such as aluminum, stainless steel, titanium, and molybdenum, and composite materials of metal and ceramics such as Thermit are preferably used.

[0069] The composite sheet 10 produced according to the present invention preferably has the following configuration. The height H of the protrusion 5 (see FIG. 1) is preferably 1 mm or more, and more preferably 3 mm or more. Moreover, the height H of the protrusion 5 is preferably 10 mm or less, and more preferably 6 mm or less. Unit area of ​​composite sheet 10 (1 cm 2 The number of protrusions 5 per 10 mm is preferably 1 or more, and more preferably 6 or more. Also, the unit area of ​​the composite sheet 10 (1 cm 2 The number of protrusions 5 per unit area is preferably 20 or less, and more preferably 15 or less. The bottom dimension A of the protrusion 5 in the X direction (see FIG. 1) is preferably 0.5 mm or more, and more preferably 1.0 mm or more. The bottom dimension A is preferably 5.0 mm, and more preferably 4.0 mm or less. The bottom dimension B of the protrusion 5 in the Y direction (see FIG. 1) is preferably 1.0 mm or more, and more preferably 2.0 mm or more. The bottom dimension B is preferably 10.0 mm or less, and more preferably 7.0 mm or less. The ratio of the bottom dimension A in the X direction to the bottom dimension B in the Y direction (bottom dimension A:bottom dimension B) is preferably 1:1 or more, and more preferably 1:2 or more. Moreover, the ratio (bottom dimension A:bottom dimension B) is preferably 1:10 or less, and more preferably 2:5 or less. The bottom area of ​​the protrusion 5 (bottom dimension A × bottom dimension B) is 0.5 mm 2 More than 2mm is preferable. 2 The above is more preferable. The bottom area of ​​the protrusion 5 is 50 mm 2 Less than 20mm is preferable 2 The following is more preferred:

[0070] The dimension C (see FIG. 1) of the fused portion 4 in the X direction is preferably 0.5 mm or more, and more preferably 0.8 mm or more. Moreover, the dimension C is preferably 2 mm or less, and more preferably 1.5 mm or less. The dimension D (see FIG. 1) of the fused portion 4 in the Y direction is preferably 1.0 mm or more, and more preferably 1.2 mm or more. Moreover, the dimension D is preferably 5.0 mm or less, and more preferably 3.0 mm or less. The ratio of the dimension C in the X direction to the dimension D in the Y direction (dimension C:dimension D) is preferably 1:1 or more, and more preferably 2:3 or more. Moreover, the ratio (dimension C:dimension D) is preferably 1:3 or less, and more preferably 2:5 or less.

[0071] The area of ​​the fused portion 4 inside the outer periphery is 0.5 mm 2 More than 1.0mm is preferable. 2 The above is more preferable. The area inside the outer periphery of the fused portion 4 is 5.0 mm 2 Less than 4.0mm is preferable 2 The following is more preferred: The area of ​​the through-hole 6 is also included in the “area inside the outer periphery of the fused portion 4 ”. The opening area of ​​the through holes 6 is preferably 50% or more, and more preferably 80% or more, of the area inside the outer periphery of the fused portion 4. The opening area of ​​the through holes 6 is preferably less than 100% of the area inside the outer periphery of the fused portion 4, and more preferably 95% or less. The opening area of ​​the through hole 6 is 1 mm 2 More than 3mm is preferable. 2 The above is more preferable. The opening area of ​​the through hole 6 is 10 mm 2 Less than 7mm is preferable 2 The following is more preferred:

[0072] The composite sheet 10 has an uneven surface and, in addition, has a fused portion 4 with a through hole 6 at the bottom of the depressions 3 that make up the uneven surface, so that the composite sheet 10 has excellent touch and liquid diffusion prevention properties in the planar direction, and also has excellent breathability and liquid absorption properties. Taking advantage of these characteristics, the composite sheet 10 is preferably used as a constituent member of absorbent articles such as disposable diapers, sanitary napkins, panty liners, and incontinence pads, and is particularly suitable as a top sheet for absorbent articles. When the composite sheet 10 is used as a top sheet of an absorbent article, typically, the first sheet 1 forms the surface facing the wearer's skin (skin-facing surface), and the second sheet 2 forms the surface facing the absorbent body when worn (non-skin-facing surface).

[0073] The composite sheet 10 can also be used for purposes other than as a topsheet for absorbent articles. Examples of uses of the composite sheet 10 for absorbent articles other than as a top sheet include a sheet that is placed between the top sheet and the absorbent body and is also called a second sheet, sublayer, etc.; and a sheet for forming a leakproof wall (particularly a sheet that forms the inner wall of a leakproof wall) that is also called a three-dimensional gather, leakproof cuff, etc. Examples of applications of the composite sheet 10 other than absorbent articles include cleaning sheets, particularly cleaning sheets that are primarily intended for absorbing liquids, and cosmetic sheets for personal use. When the composite sheet 10 is used as a cleaning sheet, it is preferable to use the first sheet 1 side facing the surface to be cleaned, since the protrusions 5 have good conformability to the uneven surface to be cleaned. When the composite sheet 10 is used as a cosmetic sheet, it is preferable to use it with the first sheet 1 side facing the skin, since the raised portions 5 conform to the skin of the subject, provide a massage effect, and absorb excess cosmetic agent (used separately) and sweat.

[0074] Although the present invention has been described above based on its preferred embodiment, the present invention is not limited to the above embodiment and can be modified as appropriate without departing from the spirit of the present invention. The configuration of one embodiment described above can be applied to other embodiments.

[0075] The following supplementary notes are further disclosed regarding the above-described embodiment of the present invention. <1> A method for producing a composite sheet having a plurality of fused portions formed by fusing a first sheet and a second sheet, the fused portions having through holes, comprising the steps of: a stacking step of stacking the first sheet and the second sheet while conveying them in the same direction to form a laminated sheet; an ultrasonic treatment step of conveying the laminated sheet into a clearance between a peripheral surface of an anvil roll and a vibration application surface at a tip of an ultrasonic horn of an ultrasonic fusion machine arranged opposite the peripheral surface, and bringing the vibration application surface into contact with one surface of the laminated sheet to apply ultrasonic vibrations to form the fused portion; A method for manufacturing a composite sheet, comprising contacting a surface of the laminated sheet that will be in contact with the vibration application surface in the clearance with an edge of an inlet of the clearance of the ultrasonic horn immediately before the laminated sheet is transported into the clearance. <2> In the overlapping step, the first sheet is conveyed while being held on a peripheral surface portion of the anvil roll, and the second sheet is overlapped on the first sheet during conveyance to form the laminated sheet; The laminated sheet is conveyed while being held on the peripheral surface of the anvil roll, and is brought into the clearance. <1> A method for producing the composite sheet according to claim 1. <3> the through hole is formed in the laminated sheet by contact of the ultrasonic horn with an edge of an entrance of the clearance immediately before the laminated sheet is introduced into the clearance; <1> or <2> A method for producing the composite sheet according to claim 1. <4> preheating at least one of the first sheet and the second sheet before applying the ultrasonic vibration; <1> ~ <3> 13. A method for producing the composite sheet according to any one of claims 1 to 12. <5> The vibration application surface is heated, and in the ultrasonic treatment step, ultrasonic vibration is applied using the heated vibration application surface and a peripheral surface of an anvil roll. <1> ~ <4> 13. A method for producing the composite sheet according to any one of claims 1 to 12. <6> As the anvil roll, a concave-convex roll having concaves and convexes on a peripheral surface is used, In the overlapping step, while rotating the uneven roll, the first sheet is caused to follow the peripheral surface of the uneven roll and deformed into an uneven shape, and the deformed first sheet is conveyed while being held on the peripheral surface of the uneven roll, and the second sheet is overlapped on the first sheet during conveyance to form the laminated sheet, The composite sheet is characterized in that at least a part of the portion of the first sheet other than the fused portion has a protrusion protruding to a side opposite to the second sheet side. <1> ~ <5> 13. A method for producing the composite sheet according to any one of claims 1 to 12. <7> In the overlapping step, in addition to the concave-convex roll, another concave-convex roll having concaves and convexes on its peripheral surface that mesh with the concaves and convexes on the peripheral surface of the concave-convex roll is used, and both rolls are rotated so that an intermeshing portion is formed between the concaves and convexes of both rolls, and the first sheet is introduced into the intermeshing portion to deform the first sheet into an uneven shape. <6> A method for producing the composite sheet according to claim 1. <8> At least one of the first sheet and the second sheet is configured to include a nonwoven fabric. <1> ~ <7> 13. A method for producing the composite sheet according to any one of claims 1 to 12. <9> At least one of the first sheet and the second sheet is configured to contain polyethylene terephthalate. <1> ~ <8> 13. A method for producing the composite sheet according to any one of claims 1 to 12.

[0076] <10> Each of the plurality of fused portions has a shape elongated in one direction (rectangular shape) in a plan view, and the through hole having a shape elongated in the one direction (rectangular shape) in a plan view is formed inside each of the plurality of fused portions. <1> ~ <9> 13. A method for producing the composite sheet according to any one of claims 1 to 12. <11> Each of the fused portions is formed in an annular shape surrounding the through hole. <1> ~ <10> 13. A method for producing the composite sheet according to any one of claims 1 to 12. <12> The fused portion is in the form of a film. <1> ~ <11> 13. A method for producing the composite sheet according to any one of claims 1 to 12. <13> The contact of the laminated sheet with the ultrasonic horn at the edge of the inlet of the clearance immediately before the laminated sheet is introduced into the clearance is intentional. <1> ~ <12> 13. A method for producing the composite sheet according to any one of claims 1 to 12.

[0077] <14> A manufacturing apparatus for a composite sheet having a plurality of fused portions where a first sheet and a second sheet are fused, and through holes are formed in the fused portions, an ultrasonic processing unit having an anvil roll and an ultrasonic fusion machine, the ultrasonic fusion machine including an ultrasonic horn disposed opposite to the peripheral surface of the anvil roll, and a clearance through which a workpiece is carried in is provided between the peripheral surface of the anvil roll and a vibration application surface at the tip of the ultrasonic horn; a workpiece conveying section that conveys the first sheet and the second sheet in the same direction while overlapping them to form a laminated sheet, and conveys the laminated sheet, which is the workpiece, into the clearance; the ultrasonic processing unit is configured to apply ultrasonic vibrations to one surface of the laminated sheet conveyed into the clearance by contacting the vibration application surface with the one surface of the laminated sheet conveyed into the clearance, thereby forming the fused portion, a surface of the laminated sheet that contacts the vibration application surface in the clearance is brought into contact with an entrance edge of the clearance of the ultrasonic horn immediately before the laminated sheet is transported into the clearance. <15> A distance between the peripheral surface of the anvil roll and the vibration application surface at an entrance of the clearance is shorter than a thickness of the workpiece just before the workpiece is brought into the entrance. <14> An apparatus for manufacturing the composite sheet according to claim 1. <16> When the center of the transport direction of the workpiece on the vibration application surface is located on a virtual straight line passing through the rotation center of the anvil roll and extending in the radial direction of the anvil roll, the center is located downstream of the reference position in the transport direction when the center of the transport direction of the workpiece on the vibration application surface is set as a reference position. <14> or <15> An apparatus for manufacturing the composite sheet according to claim 1. <17> The vibration application surface has a shape that follows a contour line of the peripheral surface of the anvil roll in a cross-sectional view along the transport direction of the workpiece. <14> ~ <16> 13. An apparatus for manufacturing a composite sheet according to any one of claims 1 to 12. <18> a preheating means for preheating at least one of the first sheet and the second sheet before applying the ultrasonic vibration; <14> ~ <17> 13. An apparatus for manufacturing a composite sheet according to any one of claims 1 to 12. <19> The vibration applying surface is heated by a horn heating means. <14> ~ <18> 13. An apparatus for manufacturing a composite sheet according to any one of claims 1 to 12. <20> The tip of the ultrasonic horn includes a heat storage portion fixed to a metallic body of the ultrasonic horn, and the vibration application surface is formed from the heat storage portion. <14> ~ <19> 13. An apparatus for manufacturing a composite sheet according to any one of claims 1 to 12. <21> The ultrasonic fusion machine is fixed on a movable table, The height of the clearance and the pressure applied to the workpiece carried into the clearance can be adjusted by moving the position of the movable table forward and backward along a direction approaching the peripheral surface of the anvil roll. <14> ~ <20> 13. An apparatus for manufacturing a composite sheet according to any one of claims 1 to 12. <22> The vibration application surface has an arc shape recessed in a direction away from the rotation axis of the anvil roll in a cross-sectional view along the transport direction of the workpiece. <14> ~ <21> 13. An apparatus for manufacturing a composite sheet according to any one of claims 1 to 12.

[0078] <23> The anvil roll is a concave-convex roll having concaves and convexes on a peripheral surface thereof, the workpiece transport section causes the first sheet to follow the peripheral surface of the uneven roll to deform the first sheet into an uneven shape, and then overlays the second sheet on the deformed first sheet to form the laminated sheet; <14> ~ <22> 13. An apparatus for manufacturing a composite sheet according to any one of claims 1 to 12. <24> The tip surface of the convex portion constituting the concave-convex peripheral surface portion of the concave-convex roll has a rectangular shape having a long side along the rotation direction of the concave-convex roll and a short side along the rotation axis direction of the concave-convex roll. <23> An apparatus for manufacturing the composite sheet according to claim 1. <25> The uneven roll is formed into a roll shape by combining a plurality of gears having a predetermined tooth width. <23> or <24> An apparatus for manufacturing the composite sheet according to claim 1. <26> The recess of the gear in the uneven roll forms a concave portion of the unevenness on the peripheral surface of the uneven roll, and a suction hole is formed at the bottom of the recess of the gear, The first sheet is maintained in a state in which it is deformed into a concave-convex shape by conforming to the peripheral surface of the concave-convex roll due to a suction force of the suction holes. <25> An apparatus for manufacturing the composite sheet according to claim 1. <27> A predetermined gap is provided between adjacent gears in the uneven roll. <25> or <26> An apparatus for manufacturing the composite sheet according to claim 1. <28> In a state in which the vibration application surface faces the tip surfaces of the convex portions that constitute the concave-convex portions of the peripheral surface portion of the concave-convex roll and the clearance is provided between the vibration application surface and the tip surfaces of the convex portions, When the convex portion is located upstream of a virtual perpendicular line that passes through the rotation center of the concave-convex roll, extends in the radial direction of the concave-convex roll, and is perpendicular to the vibration application surface, in the rotation direction of the concave-convex roll (the transport direction of the workpiece, MD), the distance between the vibration application surface and the tip surface of the convex portion (the clearance height) gradually decreases from the upstream side to the downstream side in the rotation direction (MD), When the convex portion overlaps with the virtual perpendicular line, the distance between the vibration application surface and the tip surface of the convex portion (the height of the clearance) gradually decreases from the entrance of the clearance toward the virtual perpendicular line, becomes minimum at the position of the virtual perpendicular line, and gradually increases from the virtual perpendicular line toward the exit of the clearance, When the convex portion is located downstream of the virtual perpendicular line in the rotation direction (MD), the separation distance (the height of the clearance) between the vibration application surface and the tip surface of the convex portion gradually increases from the upstream side to the downstream side in the rotation direction (MD). <23> ~ <27> 13. An apparatus for manufacturing a composite sheet according to any one of claims 1 to 12. <29> In addition to the uneven roll, another uneven roll having unevenness on its peripheral surface that meshes with the unevenness on the peripheral surface of the uneven roll is further provided, and both rolls are rotated so that an intermeshing portion is formed between the unevenness of both rolls, and the first sheet is introduced into the intermeshing portion to deform the first sheet into an uneven shape. <23> ~ <27> 13. An apparatus for manufacturing a composite sheet according to any one of claims 1 to 12. [Explanation of symbols]

[0079] 10A Laminated Sheet 10 Composite Sheet 1 Sheet 1 2. Second Sheet 3. Recess 4 Fusion part 5 Convex 6 Through holes 20. Composite sheet manufacturing equipment 30 Processing object conveying section (uneven shaping section) 31 First roll (anvil roll, uneven roll) 32 2nd roll (uneven roll) 33 Engagement part 34 Suction hole 35 Convex 35c Tip surface of convex part 36 Ultrasonic vibration application part 40 Ultrasonic processing unit 41 Ultrasonic fusion machine 42, 42A, 42B Ultrasonic horn 420 Ultrasonic horn body 421 Vibration application surface (tip surface of ultrasonic horn) 425 Heat storage section 43 Converter 44 Booster 45 Movable platform 46 Clearance 47 Clearance entrance edge of ultrasonic horn 50 Preheating mechanism 51 Preheating means 60 Horn heating mechanism 61 Horn heating means

Claims

1. A method for producing a composite sheet having a plurality of fused portions formed by fusing a first sheet and a second sheet, the fused portions having through holes, comprising the steps of: Using a manufacturing device having an anvil roll and an ultrasonic fusion machine, a stacking step of stacking the first sheet and the second sheet while conveying them in the same direction to form a laminated sheet; an ultrasonic treatment step of conveying the laminated sheet into a clearance between a peripheral surface of the anvil roll and a vibration application surface at a tip of an ultrasonic horn of the ultrasonic fusion machine arranged opposite the peripheral surface, and bringing the vibration application surface into contact with one surface of the laminated sheet to apply ultrasonic vibrations to form the fusion portion; a configuration is adopted in the manufacturing apparatus for bringing a surface of the laminate sheet that comes into contact with the vibration application surface in the clearance into contact with an edge portion of an entrance of the clearance in the ultrasonic horn immediately before the laminate sheet is carried into the clearance, and the through hole is formed in the laminate sheet by the contact of the laminate sheet with the edge portion of the entrance; The method for producing a composite sheet includes the following configurations 1 and 2. Configuration 1: The distance between the peripheral surface of the anvil roll and the vibration application surface at the inlet of the clearance is made shorter than the thickness of the laminated sheet brought into the inlet just before being brought in. Configuration 2: When the center of the transport direction of the laminated sheet on the vibration application surface is located on a virtual straight line passing through the rotation center of the anvil roll and extending in the radial direction of the anvil roll, if the position of the center of the transport direction of the laminated sheet on the vibration application surface is taken as a reference position, the center is located downstream of the reference position in the transport direction.

2. In the overlapping step, the first sheet is conveyed while being held on a peripheral surface portion of the anvil roll, and the second sheet is overlapped on the first sheet during conveyance to form the laminated sheet; The method for producing a composite sheet according to claim 1 , wherein the laminated sheet is conveyed while being held on the peripheral surface of the anvil roll, and is brought into the clearance.

3. The method for producing a composite sheet according to claim 1 or 2, further comprising preheating at least one of the first sheet and the second sheet before applying the ultrasonic vibrations thereto.

4. The method for producing a composite sheet according to any one of claims 1 to 3, wherein the vibration application surface is heated, and in the ultrasonic treatment step, ultrasonic vibration is applied using the heated vibration application surface and a peripheral surface of an anvil roll.

5. As the anvil roll, a concave-convex roll having concaves and convexes on a peripheral surface is used, In the overlapping step, while rotating the uneven roll, the first sheet is caused to follow the peripheral surface of the uneven roll and deformed into an uneven shape, and the deformed first sheet is conveyed while being held on the peripheral surface of the uneven roll, and the second sheet is overlapped on the first sheet during conveyance to form the laminated sheet, The method for producing a composite sheet according to any one of claims 1 to 4, wherein at least a portion of a portion of the first sheet other than the fused portion has a convex portion protruding on a side opposite to the second sheet side.

6. The method for producing a composite sheet as described in claim 5, wherein in the overlapping step, in addition to the uneven roll, another uneven roll having unevenness on its peripheral surface that meshes with the unevenness on the peripheral surface of the uneven roll is used, and both rolls are rotated so that an interlocking portion is formed between the unevennesses of the two rolls, and the first sheet is introduced into the interlocking portion to deform the first sheet into an uneven shape.

7. The method for producing a composite sheet according to any one of claims 1 to 6, wherein at least one of the first sheet and the second sheet is configured to include a nonwoven fabric.

8. The method for producing a composite sheet according to any one of claims 1 to 7, wherein at least one of the first sheet and the second sheet contains polyethylene terephthalate.

9. A manufacturing apparatus for a composite sheet having a plurality of fused portions formed by fusing a first sheet and a second sheet, the fused portions each having a through hole, the manufacturing apparatus comprising: an ultrasonic processing unit having an anvil roll and an ultrasonic fusion machine, the ultrasonic fusion machine including an ultrasonic horn disposed opposite to the peripheral surface of the anvil roll, and a clearance through which a workpiece is carried in is provided between the peripheral surface of the anvil roll and a vibration application surface at the tip of the ultrasonic horn; a workpiece conveying section that conveys the first sheet and the second sheet in the same direction while overlapping them to form a laminated sheet, and conveys the laminated sheet, which is the workpiece, into the clearance; the ultrasonic processing unit is configured to apply ultrasonic vibrations to one surface of the laminated sheet conveyed into the clearance by contacting the vibration application surface with the one surface of the laminated sheet conveyed into the clearance, thereby forming the fused portion, a structure is provided for bringing a surface of the laminated sheet that comes into contact with the vibration application surface in the clearance into contact with an edge portion of an entrance of the ultrasonic horn for the clearance immediately before the laminated sheet is carried into the clearance, and the through hole is formed in the laminated sheet by the contact of the laminated sheet with the edge portion of the entrance; The above-mentioned configuration includes the following configurations 1 and 2. Configuration 1: The distance between the peripheral surface of the anvil roll and the vibration application surface at the inlet of the clearance is made shorter than the thickness of the workpiece brought into the inlet just before it is brought in. Configuration 2: When the center of the transport direction of the workpiece on the vibration application surface is located on a virtual straight line passing through the center of rotation of the anvil roll and extending in the radial direction of the anvil roll, if the position of the center of the transport direction of the workpiece on the vibration application surface is taken as a reference position, the center is located downstream of the reference position in the transport direction.

10. 10. The composite sheet manufacturing apparatus according to claim 9, wherein the vibration application surface has a shape that follows a contour line of the peripheral surface of the anvil roll in a cross-sectional view along a transport direction of the workpiece.

11. 11. The composite sheet manufacturing apparatus according to claim 9, further comprising a preheating means for preheating at least one of the first sheet and the second sheet before the ultrasonic vibration is applied to the first sheet and the second sheet.

12. 12. The composite sheet manufacturing apparatus according to claim 9, further comprising a horn heating means for heating the vibration application surface.

13. The anvil roll is a concave-convex roll having concaves and convexes on a peripheral surface thereof, The composite sheet manufacturing apparatus according to any one of claims 9 to 12, wherein the workpiece transport section causes the first sheet to follow the peripheral surface of the uneven roll to deform it into an uneven shape, and then overlaps the second sheet on the deformed first sheet to form the laminated sheet.

14. The composite sheet manufacturing apparatus of claim 13 further comprises, in addition to the uneven roll, another uneven roll having unevenness on its peripheral surface that meshes with the unevenness on the peripheral surface of the uneven roll, and both rolls are rotated so that an interlocking portion is formed between the unevennesses of both rolls, and the first sheet is introduced into the interlocking portion to deform the first sheet into an uneven shape.

15. The composite sheet manufacturing apparatus according to any one of claims 9 to 14, wherein the tip of the ultrasonic horn includes a heat storage section fixed to a metal body of the ultrasonic horn, and the vibration application surface is formed from the heat storage section.

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