Method for manufacturing elastic laminate

Abstract

To provide a production method of a flexible laminate capable of producing a proper flexible laminate.SOLUTION: A production method of a flexible laminate comprises: a mark applying step for applying a mark 18 to an original fabric sheet 90; a dividing step for dividing the original fabric sheet 90 into a first continuous sheet 91 and a second continuous sheet 92; a transport step for transporting both the sheets 91, 92; a measuring step for measuring positions of recess parts 91c, 92c of both the sheets 91, 92 and a position of the mark 18; a determining step for determining, on the basis of a measurement result in the measuring step, necessity of position control of both the sheets 91, 92 and necessity of position control of the mark 18 in the transport step; and a control step for controlling, out of the positions of both the sheets 91, 92 in a transport direction in the transport step, and the position where the mark 18 is applied in the mark applying step, for which control is required, on the basis of the determination result in the determining step.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for producing a stretchable laminate that forms a ring-shaped structure that is stretchable in the circumferential direction and can be used as a component of various articles that require stretchability. [Background technology]

[0002] A separate type of pants-type absorbent article is known, which comprises an absorbent pad section including an absorbent core that absorbs and retains bodily fluids, and an annular holder section (waistband) that is placed around the wearer's waist and holds the absorbent pad section against the wearer's crotch, and the absorbent pad section is configured to be detachable from the holder section. The holder section is typically mainly made of a stretchable laminate in which multiple sheets are laminated, such as a stretchable sheet that is stretchable in the circumferential direction and a fastening sheet for the holder section (for example, a female member of a mechanical hook-and-loop fastener).

[0003] Incidentally, Patent Document 1 describes a method for manufacturing a sheet-like member for a non-separate-type absorbent article from a continuous sheet. The manufacturing method in Patent Document 1 includes a supplying step in which the continuous sheet is fed to a processing unit by conveying the continuous sheet in the conveying direction in the same direction as the continuous sheet, a processing step in which the processing unit intermittently processes each portion of the continuous sheet that will become an absorbent article in the conveying direction at a predetermined position in the conveying direction, and a detection step in which traces of the processing remaining on the continuous sheet are detected and the detection results are output. Furthermore, in the manufacturing method of Patent Document 1, the tension value of the continuous sheet in the conveying direction in the continuous sheet is adjusted based on the detection results in the supplying step when the continuous sheet is fed to the processing unit.

[0004] Furthermore, Patent Document 2 describes a manufacturing method for a package in which non-separate absorbent articles are packaged in a packaging sheet. The manufacturing method in Patent Document 2 includes a conveying step of conveying a continuous sheet on which display elements are repeatedly formed by a first conveying section and a second conveying section, a joining step of sequentially joining absorbent articles at a joining position located between the first conveying section and the second conveying section, a folding step of folding the continuous sheet, and a cutting step of cutting the continuous sheet to produce a package. In Patent Document 2, in the conveying step, the first conveying speed of the first conveying section and the second conveying speed of the second conveying section are increased or decreased based on misalignment information of the display elements, thereby controlling the conveyance of the continuous sheet so that the absorbent articles join at the correct position on the continuous sheet. In this conveyance control, the second conveying speed is increased when the first conveying speed is increased, and the second conveying speed is decreased when the first conveying speed is decreased.

[0005] Patent Document 3 also describes a method for manufacturing a sheet-like member in which a continuous first sheet and a continuous second sheet are overlapped at a joining position to form a continuous array of non-separate absorbent articles. In the manufacturing method of Patent Document 3, a stretchable first sheet on which images are periodically formed is supplied from a roll. Next, the feed speed of the first sheet is controlled so that one unit of the first sheet for an absorbent article is fed out each time one unit of the sheet-like member for an absorbent article is conveyed, and the first sheet is fed out toward the joining position. The image on the first sheet is then detected, and based on the image detection result, the path length from the feed position where the feed speed of the first sheet is controlled to the joining position is changed to adjust the position of the image relative to the absorbent article. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2017 / 175389 [Patent Document 2] Japanese Patent Application Publication No. 2019-41844 [Patent Document 3] International Publication No. 2017 / 221385 Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Documents 1 to 3 propose techniques for enabling predetermined processing to be performed at appropriate positions in a production line for components of non-separate-type absorbent articles. However, Patent Documents 1 to 3 do not consider at all how to enable predetermined processing to be performed at appropriate positions in a production line for the stretch laminate that forms the main body of the holder of a separate-type absorbent article. It is desirable to enable predetermined processing to be performed at appropriate positions in a production line for the stretch laminate that forms the main body of the holder, so that an appropriate stretch laminate can be produced.

[0008] An object of the present invention is to provide a technique capable of producing an appropriate stretchable laminate. [Means for solving the problem]

[0009] The present invention provides a method for producing a stretchable laminate comprising a first stretchable sheet that is stretchable in one direction, and a second stretchable sheet that is overlaid on one side of the first stretchable sheet and is stretchable in the same direction, the two stretchable sheets being joined to each other at a pair of joining sections formed at both ends of the first stretchable sheet in the same direction, the two stretchable sheets not being joined to each other at a portion sandwiched between the pair of joining sections, and the portion sandwiched between the pair of joining sections being capable of forming a ring-shaped structure that is stretchable in the circumferential direction, a marking step of applying a mark to a continuous band-like stretchable raw sheet that is continuous in one direction and stretched in the one direction, while conveying the raw sheet in the one direction as a conveying direction, using a marking device; a dividing step of dividing the raw sheet to which the marks have been applied into two equal parts in a direction perpendicular to the conveyance direction, and cutting the raw sheet along a planned cutting line that meanders symmetrically with respect to a center line extending parallel to the conveyance direction, thereby dividing the raw sheet into a first continuous sheet in which a plurality of first stretchable sheets are connected in the conveyance direction, and a second continuous sheet in which a plurality of second stretchable sheets are connected in the conveyance direction; a rotating step of rotating one or both of the first and second continuous sheets around the conveyance direction while conveying the first and second continuous sheets in the conveyance direction so that the cut edges of the first and second continuous sheets at the intended cutting lines face the same direction; a conveying step of conveying the first continuous sheet by first position control conveying rolls and conveying the second continuous sheet by second position control conveying rolls; a measuring step of imaging the first continuous sheet with a first imaging device and the second continuous sheet with a second imaging device, and measuring, from the images obtained by imaging, the positions of the recessed portions of the cut edges of the first continuous sheet and the second continuous sheet in the conveying direction, as well as the position of the mark provided on the first continuous sheet or the second continuous sheet; a lamination step of overlapping the first continuous sheet and the second continuous sheet such that the cut edge portions of both continuous sheets are aligned in phase with each other in the conveying direction to obtain a continuous laminate; a joining step of intermittently forming the joint portions on the continuous laminate in the conveying direction; a cutting step of cutting the continuous laminate in the conveyance direction orthogonal to form the elastic laminate into individual sheets; a determining step of determining, based on the measurement results obtained in the measuring step, whether or not position control of the first continuous sheet in the conveying direction is necessary and whether or not position control of the second continuous sheet in the conveying direction is necessary, and whether or not position control of the marks on the first continuous sheet and the second continuous sheet is necessary in the marking step; The present invention provides a method for manufacturing an elastic laminate, which includes a control step of controlling, based on the judgment result of the judgment step, the position of the first continuous sheet in the conveying direction in the conveying step, the position of the second continuous sheet in the conveying direction, and the position at which the mark is applied in the marking step, which are judged to require control. [Effects of the Invention]

[0010] According to the method for producing a stretchable laminate of the present invention, an appropriate stretchable laminate can be produced. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic plan view of one embodiment of a stretchable laminate (a holder part of a pants-type disposable diaper) produced by the production method of the present invention. [Figure 2] FIG. 2 is a cross-sectional view that schematically shows a cross section taken along line II in FIG. 1 (a cross section along the width direction and thickness direction of the elastic laminate shown in FIG. 1). [Figure 3] FIG. 3 is a schematic perspective view of one embodiment of a pants-type disposable diaper using the stretchable laminate shown in FIG. [Figure 4] FIG. 4 is a partially cutaway plan view schematically illustrating the skin-facing side of the diaper shown in FIG. 3 in an unfolded and stretched state. [Figure 5] FIG. 5 is a partially cutaway perspective view that schematically shows an example of a stretch sheet (outer layer sheet) according to the present invention. [Figure 6] FIG. 6 is a schematic perspective view of a manufacturing apparatus used to manufacture the stretchable laminate shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view schematically showing a cross section taken along line II-II in FIG. 6 (a cross section along the direction perpendicular to the conveyance direction and the thickness direction of the raw sheet precursor). [Figure 8] FIG. 8 is a cross-sectional view schematically showing a cross section of the raw sheet manufactured by the manufacturing apparatus shown in FIG. 6, taken along a direction perpendicular to the conveyance direction and in the thickness direction. [Figure 9] FIG. 9 is a schematic diagram of the manufacturing line (second manufacturing section) for the elastic laminate in the manufacturing apparatus shown in FIG. [Figure 10]Figure 10 is a diagram showing an overview of an example of a series of steps from dividing a raw sheet to obtaining a continuous laminate in the manufacturing method of the present invention, where Figure 10(a) is a schematic plan view of the raw sheet before the dividing step in the manufacturing apparatus shown in Figure 6, Figure 10(b) is a schematic plan view of two continuous sheets obtained by the dividing step, Figure 10(c) is a schematic plan view showing how the two continuous sheets are aligned in the conveying direction, and Figure 10(d) is a schematic plan view of the continuous laminate obtained by overlapping the two continuous sheets. [Figure 11] FIG. 11 is a plan view schematically showing an image obtained by imaging the first continuous sheet by the first imaging device in the manufacturing apparatus shown in FIG. [Figure 12] 12(a) and 12(b) are diagrams illustrating misalignment that may occur in this manufacturing method, and are plan views schematically showing images obtained by imaging the first continuous sheet with the first imaging device. [Figure 13] 13(a) to 13(c) are plan views schematically showing other examples of images obtained by imaging the first continuous sheet with the first imaging device in the manufacturing apparatus shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] 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 designated by the same or similar reference numerals. The drawings are basically schematic, and the ratios of the dimensions may differ from those of the actual ones.

[0013] 1 and 2 show a stretchable laminate 1, which is one embodiment of a stretchable laminate produced by the production method of the present invention. The stretchable laminate 1 comprises a first stretchable sheet 1A that is stretchable in one direction, specifically the longitudinal direction of the stretchable laminate 1, designated by the symbol Y in the figures, and a second stretchable sheet 1B that is overlaid on one side of sheet 1A and is stretchable in direction Y. Both sheets 1A, 1B are joined to each other at a pair of joints 9, 9 formed at both ends of the sheets in direction Y, and are not joined to each other in the portion sandwiched between the pair of joints 9, 9, so that the portion sandwiched between the pair of joints 9, 9 can form a ring-shaped structure that is stretchable in the circumferential direction.

[0014] As shown in Figures 3 and 4, the stretchable laminate 1 is used as a holder part 17, which is a component of a pants-type disposable diaper 10, which is a type of pants-type absorbent article. As shown in Figure 4, the diaper 10 has a vertical direction (direction X) extending from the wearer's abdomen through the crotch region to the back, and a horizontal direction (direction Y) perpendicular to the vertical direction, and is equipped with an absorbent pad part 11 including an absorbent core 14 that absorbs and retains bodily fluids, and an annular holder part 17 (stretchable laminate 1) that is disposed around the wearer's waist and holds the absorbent pad part 11 against the wearer's crotch region. Direction X is the width direction (short direction) of the elastic laminate 1 (sheets 1A, 1B) and also the vertical direction of the diaper 10, and direction Y is the longitudinal direction of the elastic laminate 1 (sheets 1A, 1B) and also the horizontal direction of the diaper 10.

[0015] The absorbent pad portion 11 is configured to be detachable from the holder portion 17. That is, the absorbent pad portion 11 and the holder portion 17 are separate components before the diaper 1 is used. When the diaper 1 is used, the absorbent pad portion 11 and the holder portion 17 are joined together by fastening a fastening tape 16 (described later) of the absorbent pad portion 11 to a target tape 7 of the holder portion 17, thereby forming a pants-type diaper having a pair of joining portions 9, 9, a waist opening WH, and a pair of leg openings LH, LH, as shown in FIG. 3 . The joining portion 9 of the holder portion 17 corresponds to the side seal portion of a typical non-separate pants-type disposable diaper. In this embodiment, the joining portion 9 is linear and extends along the direction X, spanning the entire length of the elastic laminate 1 in the direction X.

[0016] As shown in Figures 3 and 4, the absorbent pad 11 includes a liquid-permeable top sheet 12 positioned relatively close to the wearer's skin, a liquid-impermeable, poorly liquid-permeable, or water-repellent back sheet 13 positioned relatively far from the wearer's skin, and an absorbent core 14 interposed between the two sheets 12, 13. These components constituting the absorbent pad 11 are joined together by a known joining means such as an adhesive. The absorbent pad 11 has a rectangular shape in a plan view, and when the diaper 10 is worn, its longitudinal direction coincides with the direction X, as shown in Figure 4. A pair of leakage-preventing cuffs 15, 15 are arranged on both sides of the absorbent pad 11 along the direction X, so as to stand toward the wearer's skin when the diaper 10 is worn. Each leakage-preventing cuff 15 includes a leakage-preventing cuff-forming sheet 150 that forms the main body of the leakage-preventing cuff 15 and an elastic member 151 fixed to the sheet 150 in a stretched state in the direction X. On the inner surface (skin-facing surface) of each of both ends of the absorbent pad portion 11 in the X direction, fastening tapes 16 for joining the absorbent pad portion 11 to the holder portion 17 are arranged.

[0017] The elastic laminate 1 that constitutes the holder section 17 is primarily a laminate of a first elastic sheet 1A and a second elastic sheet 1B. Both sheets 1A and 1B have the same shape and dimensions in a plan view as shown in Figure 1, and in the elastic laminate 1, both sheets 1A and 1B are superimposed with their respective contours aligned. The elastic laminate 1 is formed symmetrically with respect to a horizontal centerline (not shown) that bisects the elastic laminate 1 in direction Y and extends in direction X.

[0018] As shown in Figures 1 and 4, the elastic laminate 1 (sheets 1A, 1B) has a pair of longitudinal ends X1, X2 extending in direction Y. The longitudinal end X1, which is the upper end when the holder portion 17 is worn, is a straight line parallel to direction Y in plan view, while the longitudinal end X2, which is the lower end when the holder portion 17 is worn, forms a convex portion that is almost entirely convex toward the longitudinal end X1 (toward the inside of direction X) in plan view.

[0019] The first elastic sheet 1A and the second elastic sheet 1B each include an outer body 2 that forms the outer surface (non-skin-facing surface) of the elastic laminate 1, and a reinforcing sheet 5 that forms the inner surface (skin-facing surface) of the elastic laminate 1. In this specification, the term "skin-facing surface" refers to the surface of an absorbent article or its constituent parts (absorbent pad part, holder part, etc.) that faces the wearer's skin when the absorbent article is worn, and the term "non-skin-facing surface" refers to the surface of an absorbent article or its constituent parts that faces the opposite side to the skin when the absorbent article is worn. 2, the exterior body 2 in this embodiment includes an outer layer sheet 3 that forms the outer surface of the elastic laminate 1, and an inner layer sheet 4 that is superimposed on the inner surface of the outer layer sheet 3, and is mainly a laminate of the two sheets 3, 4. The two sheets 3, 4 are joined together and integrated by a joining means such as an adhesive or fusion bonding. As shown in FIG. 2, the exterior body 2 (sheets 3 and 4) is folded back inward at the longitudinal end X1 of the elastic laminate 1, thereby forming a folded-back portion 20 on the inner surface (skin-facing surface) of both sheets 1A and 1B, extending in the X direction from the longitudinal end X1. The folded-back portion 20 and the opposing exterior body 2 are joined together by a joining means such as adhesive or fusion. As shown in FIG. 2, the reinforcing sheet 5 is disposed at a position spaced a predetermined distance in the X direction from the folded-back portion 20 of the exterior body 2. The length of the reinforcing sheet 5 in the Y direction is the same as that of the exterior body 2 (sheets 3 and 4), but the length of the reinforcing sheet 5 in the X direction is shorter than that of the exterior body 2 (sheets 3 and 4). The vertical end 5a of the reinforcing sheet 5 on the folded-back portion 20 side (the upper end when the holder portion 17 is worn) is straight and parallel to the direction Y in a planar view, and the vertical end 5b of the reinforcing sheet 5 on the opposite side from the folded-back portion 20 side (the lower end when the holder portion 17 is worn) together with the outer casing 2 forms the vertical end X2 of the elastic laminate 1, and has a convex portion that is convex toward the vertical end X1 in a planar view. Nonwoven fabrics manufactured by various methods, resin films, and the like can be used for the outer layer sheet 3, inner layer sheet 4, and reinforcing sheet 5 that make up the exterior body 2. Specific examples of nonwoven fabrics that can be used for the sheets 3, 4, and 5 include spunbond nonwoven fabrics, air-through nonwoven fabrics, and needle-punched nonwoven fabrics, and they may have a single-layer structure or a laminate structure in which one or more types of nonwoven fabrics are laminated.

[0020] The outer layer sheet 3 is a stretchable sheet stretched in one direction, specifically the longitudinal direction of the stretchable laminate 1 or the transverse direction of the diaper 10, i.e., direction Y, and is stretchable in direction Y. The stretchable sheet is obtained by stretching an unstretched sheet such as a nonwoven fabric. The stretching is typically carried out using a processing means equipped with a pair of grooved rolls whose peripheral surfaces are provided with intermeshing grooves along the rotation axis direction, and by rotating the rolls to feed the unstretched sheet to the intermeshing portions. This stretching process forms high-basis weight portions and low-basis weight portions alternating in the feed direction (MD), thereby transforming the unstretched sheet into a stretched sheet with MD stretchability. The stretchable sheet can be produced, for example, according to the method described in JP 2009-61743 A.

[0021] 5 shows a stretch sheet 3A, which is a preferred example of the outer layer sheet 3. The stretch sheet 3A has two opposing fibrous sheets 31, 32 and a plurality of elastic filaments 33 disposed between the fibrous sheets 31, 32 and extending in one direction (direction Y) without crossing each other. The plurality of elastic filaments 33 are joined to the stretchable fibrous sheets 31, 32 in a substantially unstretched state over their entire longitudinal length.

[0022] Both fiber sheets 31, 32 are stretchable in the direction (direction Y) in which the elastic filaments 33 extend. Here, "stretchable" includes (1) the case where the constituent fibers of the fiber sheets 31, 32 themselves stretch, and (2) the case where the constituent fibers themselves do not stretch, but the fiber sheets 31, 32 as a whole stretch because fibers bonded at intersections become separated, the three-dimensional structure formed by multiple fibers due to bonding between fibers, etc., undergoes a structural change, or constituent fibers are torn.

[0023] The fiber sheets 31 and 32 may each be a staple fiber nonwoven fabric. Examples of nonwoven fabrics include air-through nonwoven fabrics, heat-rolled nonwoven fabrics, spunlace nonwoven fabrics, spunbond nonwoven fabrics, and meltblown nonwoven fabrics. The sheets 31 and 32 may be the same or different. Here, "the same" means that the manufacturing process, type of constituent fibers, diameter and length of the constituent fibers, thickness, and basis weight of the fiber sheet are all the same between the two fiber sheets. If even one of these is different, the two fiber sheets are "different" from each other.

[0024] The elastic filaments 33 are made from materials such as thermoplastic elastomers or rubber. Thermoplastic elastomers, in particular, can be melt-spun using an extruder, just like ordinary thermoplastic resins, and the elastic filaments thus obtained are easily heat-sealed, making them ideal for the stretch sheet 3A. A preferred example of the elastic filaments 33 is an elastic filament formed by stretching an elastic resin in a molten or softened state. The preferred elastic filaments 33 are bonded to the fiber sheets 31, 32 by fusing the constituent fibers (non-elastic fibers) of both sheets 31, 32 to the elastic filaments 33 while they are embedded in the elastic filaments 33, rather than by using an adhesive such as a hot-melt adhesive. Therefore, no adhesive is present between the fiber sheets 31, 32 and the elastic filaments 33 bonded thereto.

[0025] The inner layer sheet 4 and the reinforcing sheet 5 may each be a stretchable sheet that is stretchable in the direction Y, or a non-stretchable sheet that is not stretchable. Typically, both sheets 4 and 5 are non-stretchable sheets.

[0026] In this embodiment, the first stretchable sheet 1A and the second stretchable sheet 1B each include a functional sheet 6 in addition to the reinforcing sheet 5 as the sheet that forms the inner surface (skin-facing surface) of the stretchable laminate 1. In the present invention, the functional sheet 6 is intended to impart various functions to the holder part 17, and in this embodiment, the functional sheet 6 is intended to absorb and retain the wearer's sweat, and is arranged so as to come into contact with the wearer's skin. In this embodiment, as shown in Fig. 2, the functional sheet 6 is arranged to straddle the folded portion 20 of the exterior body 2 and the reinforcing sheet 5 in the direction X, and as shown in Fig. 4, it has a shape that is long in one direction (specifically, a rectangular shape) in a plan view, and extends continuously over the entire length of both sheets 1A and 1B in the direction Y, with its longitudinal direction coinciding with the direction Y. The length of the functional sheet 6 in the direction X is shorter than that of both sheets 1A and 1B. The sweat-absorbing functional sheet 6 is not particularly limited as long as it is a sheet that can absorb sweat, but typically, nonwoven fabrics produced by various methods are used. Specific examples of nonwoven fabrics that can be used as the sweat-absorbing functional sheet 6 include air-through nonwoven fabrics, spunbond nonwoven fabrics, spunlace nonwoven fabrics, air-laid nonwoven fabrics, meltblown nonwoven fabrics, and needle-punched nonwoven fabrics, and may also be composite nonwoven fabrics in which two or more types of nonwoven fabrics are laminated.

[0027] In this embodiment, the first stretchable sheet 1A and the second stretchable sheet 1B each include a target tape 7 disposed on the outer surface (non-skin facing surface) of the outer layer sheet 3. The target tape 7 is a fastening destination for the fastening tape 16 (see FIG. 4) provided on the absorbent pad section 11, and the absorbent pad section 11 is configured to be detachable from the holder section 17 due to the fastening tape 16 provided on the absorbent pad section 11 and the target tape 7 provided on the stretchable laminate 1 as the holder section 17. 1, the target tape 7 has a shape that is long in one direction (specifically, a rectangular shape) in a plan view, and its longitudinal direction coincides with the direction Y, and it extends continuously over the entire length of each of the sheets 1A, 1B in the direction Y. Furthermore, the length of the target tape 7 in the direction X is shorter than that of the sheets 1A, 1B, and the center of the target tape 7 in the direction X is positioned closer to the longitudinal end X2 than the centers of the sheets 1A, 1B in the direction X.

[0028] In the present invention, the configurations of the fastening tape 16 and the target tape 7 are not particularly limited, provided that the absorbent pad part 11 is detachable from the holder part 17. For example, the fastening tape 16 may be configured to have an adhesive part formed by applying an adhesive or the like to a tape base material, and the fastening tape 16 may be configured to adhere to the target tape 7 via the adhesive part. In this embodiment, mechanical hook-and-loop fasteners are used as the fastening tape 16 and the target tape 7. The term "mechanical hook-and-loop fastener" used here refers to a fastener that is a set of a surface member with hook-shaped protrusions arranged on one surface and a surface member with pile-shaped protrusions arranged on the other surface. A specific example of a mechanical hook-and-loop fastener is Magic Tape (registered trademark). The fastening tape 16 has a male member of a mechanical hook-and-loop fastener, and typically has a number of protrusion-shaped engaging members arranged on the surface of a tape substrate made of a resin film, woven fabric, nonwoven fabric, or the like. The target tape 7 has a female member of a mechanical hook-and-loop fastener, and typically has a number of loop members arranged on the surface of the substrate sheet.

[0029] In this embodiment, a mark 18 is provided on the stretchable laminate 1. The mark 18 typically serves as a guide when the fastening tape 16 is used as the target tape 7. In this embodiment, the mark 18 is provided on the target tape 7 of each of the first stretchable sheet 1A and the second stretchable sheet 1B. The mark 18 may be provided on only one of the target tape 7 of the first stretchable sheet 1A and the target tape 7 of the second stretchable sheet 1B. The mark 18 can be formed, for example, by embossing the target tape 7.

[0030] In this embodiment, as shown in FIG. 2, a plurality of elastic members 8 are arranged between the exterior body 2 (inner layer sheet 4) and the reinforcing sheet 5, and between the folded-back portion 20 and the exterior body 2 facing it, so as to be stretchable in the direction Y. As shown in FIG. 4, the plurality of elastic members 8 extend over the entire length of both sheets 1A and 1B in the direction Y and are arranged intermittently in the direction X. Each elastic member 8 is fixed to the sheets 4 and 5 that contact the elastic member 8 with an adhesive. When the holder portion 17 is worn, contraction of the elastic members 8 forms a plurality of folds (gathers) on the surfaces of both sheets 1A and 1B, extending in the direction intersecting the elastic members 8 (direction X). The number and arrangement of the elastic members 8 are not particularly limited and can be determined appropriately taking into consideration the fit of the holder portion 17 to the wearer's body, etc.

[0031] Next, a method for manufacturing a stretchable laminate of the present invention will be described with reference to the drawings, taking as an example the method for manufacturing the stretchable laminate 1 (holder portion 17) described above. Figure 6 shows a manufacturing apparatus 70 used to carry out the method for manufacturing the stretchable laminate 1. The manufacturing apparatus 70 comprises a first manufacturing unit 71 that carries out the process of manufacturing a raw sheet 90, and a second manufacturing unit 72 that manufactures the stretchable laminate 1 (holder portion 17) using the continuous strip-shaped raw sheet 90 manufactured in the first manufacturing unit 71. The first manufacturing unit 71 carries out the process of applying marks to the raw sheet 90 (mark application process). The second manufacturing section 72 performs the following processes: a process of cutting the raw sheet 90 along a planned cutting line CL (see FIG. 10(a)) extending in the conveying direction MD to divide the raw sheet 90 into a first continuous sheet 91 and a second continuous sheet 92 (dividing process); a process of rotating one or both of the sheets 91, 92 around the conveying direction MD (rotating process); a process of conveying each of the sheets 91, 92 (conveying process); and a process of measuring the positions of the recessed portions 91c, 92c of the cut edges 91a, 92a of each of the sheets 91, 92 and the position of the mark 18. The following steps are carried out: (measurement process), a process of overlapping both sheets 91, 92 to obtain a continuous laminate 93 (lamination process), a process of forming the joint 9 in the continuous laminate 93 (joining process), a process of cutting the continuous laminate 93 to obtain individual sheets of elastic laminate 1 (singling process), a process of determining whether or not position control of both sheets 91, 92 and the marks is necessary (determination process), and a process of controlling the positions of both sheets 91, 92 in the conveying process and the position at which mark 18 is applied in the mark application process (control process). A control device (not shown) is installed in the manufacturing apparatus 70. The control device is connected to drive devices (servomotors) that drive the devices used in each process of the manufacturing apparatus 70 (rolls that transport the raw sheet, joining means, dividing means, cutting means, etc.), imaging devices 96 and 97 used in the measurement process, the joining device 73, the marking device 76, and the sheet forming device 99, and performs various controls necessary to manufacture the stretchable laminate.

[0032] The method for producing the elastic laminate 1 of this embodiment includes, before the dividing step, a step for producing a raw sheet 90 that is divided into two in the cross direction CD in the dividing step. The manufacturing step for the raw sheet 90 will be described below. The raw sheet 90 is a continuous strip sheet including a continuous strip stretch sheet stretched in one direction, and in this embodiment, a continuous strip outer layer sheet 3, more specifically a continuous strip stretch sheet 3A (see Figure 5), is used as the stretch sheet. The conveying direction MD coincides with the longitudinal direction (continuous direction) of the raw sheet 90 (stretch sheet 3A), and the conveying cross direction CD, which is perpendicular to the conveying direction MD, coincides with the width direction (short direction) of the raw sheet 90 (stretch sheet 3A).

[0033] In the first manufacturing section 71, as shown in FIG. 6, a continuous strip of an inner layer sheet 4 (first raw material sheet) is placed on one side (the upper side in the illustrated embodiment) of a stretch sheet 3A being transported in the transport direction MD so as to overlap with the planned cutting line CL (see FIG. 10(a)) described below, and a pair of continuous strips of target tapes 7, 7 (second raw material sheets) are placed on both sides of the planned cutting line CL on the other side (the lower side in the illustrated embodiment) of the stretch sheet 3A in the direction perpendicular to the transport direction CD, to obtain a continuous strip of raw sheet precursor 80, and further, the sheets 3A, 4, 7 constituting the raw sheet precursor 80 are joined together. In this embodiment, the length (width) of the inner layer sheet 4 in the cross direction CD of the conveyance direction is the same as or longer than that of the stretch sheet 3A, while the length (width) of the target tape 7 in the cross direction CD of the conveyance direction is shorter than that of the stretch sheet 3A. The sheets 3A, 4, and 7 that make up the raw sheet precursor 80 are joined together by joining means 73 provided in the first manufacturing unit 71. A device conventionally used for joining sheets of this type can be used as the joining means 73. In this embodiment, the joining means 73 includes melting means 730 such as an ultrasonic horn that heats and melts the workpieces (sheets 3A, 4, and 7), and a backing roll 731, and is configured to be able to melt the workpieces supplied between the opposing peripheral surfaces of the melting means 730 and backing roll 731 while applying pressure to them.

[0034] In the present invention, the sheets 3A, 4, and 7 constituting the raw sheet precursor 80 may be joined together in multiple steps or simultaneously. When joining the sheets together in multiple steps, for example, a method can be used in which the intended joining locations of the stretch sheet 3A and the inner layer sheet 4 (first raw material sheet) are joined, and then the intended joining locations of the stretch sheet 3A and the target tape 7 (second raw material sheet) are joined, or a method can be used in which the joining is performed in the reverse order. In either case, to implement the method, multiple (e.g., two) joining means 73 must be arranged along the conveying direction MD to correspond to the multiple (e.g., two) joining steps. In contrast, in this embodiment, the sheets 3A, 4, and 7 that make up the raw sheet precursor 80 are joined simultaneously. That is, the raw sheet precursor 80 is introduced into a single joining means 73, and all of the intended joining locations are joined in a single joining process by the single joining means 73. This allows for fewer steps and simpler processing equipment than methods in which the sheets are joined in multiple separate steps, further improving manufacturing efficiency.

[0035] 6, after the sheets 3A, 4, and 7 constituting the raw sheet precursor 80 are joined together by joining means 73, a plurality of elastic members 8 are arranged and fixed in a stretched state stretched to a predetermined stretch rate on the elastic member arrangement surface (the surface on the inner layer sheet 4 side in the illustrated embodiment) of the raw sheet precursor 80 being transported in the transport direction MD. An adhesive such as a hot-melt adhesive is applied to the elastic member arrangement surface and / or the elastic members 8 by an adhesive applicator (not shown) before the elastic members 8 are arranged. By arranging the elastic members 8 on the elastic member arrangement surface, the elastic members 8 are joined and fixed to the raw sheet precursor 80.

[0036] 6, in the manufacturing process of a raw sheet 90, both side edge portions 80S, 80S along the machine direction MD of a raw sheet precursor 80 are folded back toward one side of the raw sheet precursor 80 (toward the inner layer sheet 4 in the illustrated embodiment) to form a pair of folded back portions 20, 20 and a folded back portion non-existent portion 21 located between the pair of folded back portions 20, 20 (folding step). As described above, the folded back portion 20 forms one side edge of the stretchable laminate 1 in the longitudinal direction Y (the lateral direction Y of the holder portion 17). Forming this one side edge by folding back a sheet in this manner improves the appearance of the stretchable laminate 1 and can further improve the appearance of the holder portion 17 (diaper 10).

[0037] In the folding step, any of the sheets 3A, 4, and 7 constituting the raw sheet precursor 80 may be folded, but it is preferable to fold the stretch sheet 3A and the inner layer sheet 4 (first raw material sheet) (without folding the target tape 7) as shown in Figure 7. The stretch sheet 3A is more likely to meander during transport than the other sheets constituting the raw sheet precursor 80, and if the stretch sheet 3A meanders during the manufacturing process of the stretch laminate 1, this could lead to a deterioration in the appearance and functionality of the resulting stretch laminate 1; however, by folding the stretch sheet 3A and the inner layer sheet 4 in the folding step, such problems can be effectively prevented.

[0038] In the folding step, it is preferable to fold both side edge portions 80S, 80S of the raw sheet precursor 80 toward one side of the raw sheet precursor 80 (toward the inner layer sheet 4 in the illustrated embodiment) using the elastic members 8 arranged inside the folding portion 20 as a reference. As described above, in the manufacturing process of the raw sheet 90, after joining the sheets 3A, 4, and 7 that make up the raw sheet precursor 80, the elastic members 8 are arranged in the areas where the folding portion 20 is to be formed (the both side edge portions 80S, 80S of the raw sheet precursor 80) on the inner layer sheet 4 (first raw sheet) side of the raw sheet precursor 80. Since the elastic members 8 arranged in this manner extend linearly along the conveying direction MD, in the folding step, the both side edge portions 80S, 80S of the raw sheet precursor 80 are folded using the elastic members 8 as a reference, thereby forming the folding portion 20 with a neat fold.

[0039] In this embodiment, in the manufacturing process of the raw sheet 90, as shown in Fig. 6, a continuous strip-shaped reinforcing sheet 5 (third raw sheet) is arranged in the non-folded portion 21 on the inner layer sheet 4 (first raw sheet) side of the raw sheet precursor 80 so as to overlap with the planned cutting line CL. This increases the rigidity of the non-folded portion 21 in the raw sheet 90, and effectively prevents the cut edges 91a, 92a (see Fig. 10(b)) of the first continuous sheet 91 and the second continuous sheet 92 obtained by cutting the raw sheet 90 along the planned cutting line CL in the dividing step from being turned up during the subsequent transportation of the sheets 91, 92, thereby further improving manufacturing efficiency.

[0040] In the manufacturing process of the raw sheet 90, as shown in FIGS. 6 and 8, a pair of continuous strip-shaped functional sheets 6 (fourth raw sheet) are arranged on the surface of the raw sheet precursor 80 facing the inner layer sheet 4 (first raw sheet) so as to overlap the boundary 22 between the pair of fold-back portions 20, 20 and the reinforcing sheet 5 (third raw sheet). This results in a continuous strip-shaped raw sheet 90 in which the stretch sheet 3A and the first to fourth raw sheet sheets 4 to 7 are laminated together. As shown in FIG. 8, the boundary 22 between the fold-back portion 20 and the reinforcing sheet 5 is the gap between the fold-back portion 20 and the reinforcing sheet 5, and is a portion where the number of sheets stacked in the direction X of the stretch laminate 1 is relatively small. As mentioned above, in the present embodiment, the joint 9 (see FIG. 1) extends over the entire length of the stretch laminate 1 in the direction X and overlaps with the boundary 22. If the joint 9 exists across an area where the number of sheets stacked is different, there is a concern that the bond strength of the joint 9 will vary. However, as described above, by overlapping the reinforcing sheet 5 at the boundary 22 where the number of laminated sheets is relatively small, such concerns can be eliminated, and the bonding strength of the joint 9 can be made constant over its entire length in the longitudinal direction.

[0041] In this embodiment, marks 18 are applied to the raw sheet 90 by a marking device 76 (marking step). In this embodiment, the marking device 76 is an embossing device, and includes an embossing roll 761 having convex portions on its peripheral surface, and an anvil roll 760 having a smooth peripheral surface and disposed opposite the embossing roll 761. The marks 18 are applied by embossing the raw sheet 90. The embossing is performed by compressing the raw sheet 90 by applying pressure between the convex portions of the embossing roll 761 and the smooth peripheral surface of the anvil roll 760. Examples of embossing include known embossing processes such as thermal embossing and ultrasonic embossing. In this embodiment, the convex portion of the embossing roll 761 is composed of a pair of convex portions spaced apart in the axial direction of the embossing roll 761. The embossing is performed such that each of the pair of convex portions of the embossing roll 761 applies pressure to both sides of the planned cutting line CL of the raw sheet 90 in the direction perpendicular to the conveyance direction CD.

[0042] The continuous belt-like raw sheet 90 produced in the first production unit 71 in the above manner is then transported to the second production unit 72 and used to produce the elastic laminate 1. Figure 9 shows a schematic configuration of the second production unit 72, and Figure 10 shows the state of the raw sheet 90 and other workpieces in each part of the second production unit 72.

[0043] In the second manufacturing section 72, first, the raw sheet 90 is conveyed with its continuous direction being the conveying direction MD, and cut along the planned cutting line CL (see Figure 10(a)) extending in the conveying direction MD, to divide it into a first continuous sheet 91 and a second continuous sheet 92 (division process). The dividing step is carried out by cutting means 74 provided in the second manufacturing unit 72. A device conventionally used for cutting this type of sheet can be used as the cutting means 74. In this embodiment, the cutting means 74 includes a cutter roll 740 equipped with a blade for cutting the sheet, and a receiving roll 741.

[0044] 10(a), the planned cutting line CL meanders around a center line 90L that bisects the raw sheet 90 in the cross-conveyance direction CD and extends parallel to the conveyance direction MD. In the illustrated embodiment, the planned cutting line CL meanders symmetrically with respect to the center line 90L, and therefore the first continuous sheet 91 and the second continuous sheet 92 are symmetrical with respect to the planned cutting line CL. Note that the planned cutting line CL is typically a virtual line and is not provided so as to be visible to the naked eye on the raw sheet 90, but it may be provided so as to be visible. In this embodiment, the planned cutting line CL has a shape in which, in a plan view as shown in Fig. 10(a), convex portions convex on one side in the cross-conveyance direction CD and convex portions convex on the other side are alternately arranged in the conveying direction MD. The shape of the planned cutting line CL in a plan view is not particularly limited as long as the planned cutting line CL meanders with respect to the center line 90L, and does not have to meander symmetrically with respect to the center line 90L as shown in Fig. 10(a). The shape of the planned cutting line CL in a plan view may be, for example, a shape in which the outline is made up of only straight lines, such as when the convex portions are trapezoidal in a plan view, or a shape in which the outline is made up of only curved lines, such as when the convex portions are S-shaped, or a shape in which straight lines and curved lines are mixed.

[0045] The first continuous sheet 91 has a configuration in which multiple first stretch sheets 1A are connected in one direction (the conveying direction MD), and the second continuous sheet 92 has a configuration in which multiple second stretch sheets 1B are connected in one direction (the conveying direction MD). The first continuous sheet 91 has a pair of edges extending in the conveying direction MD: a cut edge 91a that snakes around the center line 90L and an edge 91b that extends substantially parallel to the center line 90L, which are formed by cutting the raw sheet 90 along the planned cutting line CL. The second continuous sheet 92 has a pair of edges extending in the conveying direction MD: a cut edge 92a that snakes around the center line 90L and an edge 92b that extends substantially parallel to the center line 90L, which are formed by cutting the raw sheet 90 along the planned cutting line CL. The non-linear cut edges 91a, 92a form the longitudinal end X2 of the elastic laminate 1 (the lower end of the holder portion 17 when worn), and the linear edges 91b, 92b form the longitudinal end X1 of the elastic laminate 1 (the upper end of the holder portion 17 when worn) (see Figure 1, etc.).

[0046] As shown in FIG. 9, the second manufacturing unit 72 includes a conveying path 910 for the first continuous sheet 91 and a conveying path 920 for the second continuous sheet 92, and the conveying paths 910 and 920 are independent of each other over a predetermined distance.

[0047] After the dividing process, the first continuous sheet 91 and the second continuous sheet 92 are conveyed in the conveying direction MD on the conveying paths 910, 920, while one or both of the sheets 91, 92 are rotated (twisted) around the conveying direction MD so that the cutting edges 91a, 92a of the sheets 91, 92 at the planned cutting lines CL face the same direction (rotation process).

[0048] 6, in this embodiment, one side of the conveyance orthogonal direction CD is the operation side (hereinafter also referred to as the "OP side") of the manufacturing apparatus 70 used to implement the manufacturing method for the elastic laminate 1, and the other side of the conveyance orthogonal direction CD is the drive side (hereinafter also referred to as the "DR side") of the manufacturing apparatus 70, with the first continuous sheet 91 located on the OP side and the second continuous sheet 92 located on the DR side. The OP side is the side where an operator who operates the manufacturing apparatus 70 is located, and the DR side is the side where most of the driving equipment for operating each part of the manufacturing apparatus 70 is located. As described above, in the rotation process, one or both of the sheets 91, 92 may be rotated around the conveying direction MD so that the cut edge 91a of the first continuous sheet 91 and the cut edge 92a of the second continuous sheet 92 face in the same direction, and the direction in which the cut edge 91a, 92a faces after the rotation process may be either the OP side or the DR side.

[0049] In this embodiment, in order to orient the cut edges 91 a, 92 a of both sheets 91, 92 toward the DR side in the rotating step, the second continuous sheet 92, whose cut edge 92 a faces the OP side immediately after the dividing step, is rotated 180 degrees around the conveying direction MD. On the other hand, the first continuous sheet 91, whose cut edge 91 a faces the DR side immediately after the dividing step, is not rotated around the conveying direction MD. 9, the conveying path 920 for the second continuous sheet 92 is provided with a sheet rotation region 75 that rotates the second continuous sheet 92 180 degrees around the conveying direction MD during conveyance. The sheet rotation region 75 has a plurality of cylindrical conveying rolls 750 as sheet rotation means, which are arranged intermittently in the conveying direction MD with their axial directions aligned with the cross-conveyance direction CD. The conveying rolls 750 in the sheet rotation region 75 form different angles with their axial directions and the horizontal direction (vertical direction), and are arranged so that the angle increases or decreases from the upstream side to the downstream side in the conveying direction MD (from left to right in FIG. 9). The second continuous sheet 92 is rotated 180 degrees around the conveying direction MD by being conveyed through the sheet rotation region 75 configured in this manner in the conveying direction MD. The number of conveying rolls 750 arranged in the sheet rotation region 75 is not particularly limited and can be adjusted as appropriate depending on the rotation angle of the sheet, etc. The sheet rotating means is also not particularly limited and any known rotating means capable of rotating the sheet around the conveying direction during conveyance can be used as appropriate.

[0050] In the manufacturing method of the elastic laminate 1 of this embodiment, after the rotating step, the first continuous sheet 91 and the second continuous sheet 92 are each transported (transporting step). In the transporting step of this embodiment, as shown in Fig. 9, the first continuous sheet 91 is transported by first position-controlled transport rolls 94, and the second continuous sheet 92 is transported by second position-controlled transport rolls 95. Both the first position-controlled transport rolls 94 and the second position-controlled transport rolls 95 are drive rolls.

[0051] After the conveying step, the positions of the recessed portions 91c, 92c of the cut edges 91a, 92a of the first continuous sheet 91 and the second continuous sheet 92, respectively, and the positions of the marks 18 applied to the first continuous sheet 91 and the second continuous sheet 92 are measured (measuring step). In this embodiment, a first imaging device 96 is disposed on the side of the first continuous sheet 91 on which the target tape 7 is disposed, and a second imaging device 97 is disposed on the side of the second continuous sheet 92 on which the target tape 7 is disposed. In the measuring step, the first imaging device 96 images the first continuous sheet 91, and the second imaging device 97 images the second continuous sheet 92. The positions of the recessed portions 91c, 92c and the marks 18 are measured from the obtained images.

[0052] Although there are no particular limitations on the method for measuring the positions of the recessed portions 91c, 92c and the mark 18, it is preferable to measure them by a pattern matching method. The pattern matching method can be performed by searching for pre-registered partial images of the first and second continuous sheets 91, 92 (images of the recessed portions 91c, 92c or the mark 18) from the images obtained by imaging. In this regard, a method for detecting the positions of the recessed portions 91c and the mark 18 of the first continuous sheet 91 will be described in detail below. First, detection areas are set in the images captured by the first and second imaging devices 96 and 97 (see FIG. 11). In FIG. 11, reference symbol W1 denotes a detection area for detecting the mark 18, and reference symbol W2 denotes a detection area for detecting the mark 18. Then, a portion matching the pre-registered image of the recessed portion 91c or the mark 18 is searched for within the detection areas. In FIG. 11, reference symbol R1 denotes a portion matching the pre-registered image of the recessed portion 91c, and reference symbol R2 denotes a portion matching the pre-registered image of the mark 18. The center position P1 of the portion R1 in the conveying direction MD is set to the position of the recessed portion 91c in the conveying direction MD, and the center position P2 of the portion R2 in the conveying direction MD is set to the position of the mark 18 in the conveying direction MD. The positions of the recessed portion 92c and the mark 18 of the second continuous sheet 92 can also be measured using a similar method.

[0053] After the measurement step, the first continuous sheet 91 and the second continuous sheet 92 are overlapped as shown in FIG. 10(d) by aligning the phases of the cut edges 91a and 92a of both sheets 91 and 92 in the conveying direction MD as shown in FIG. 10(c), thereby obtaining a continuous laminate 93 (lamination step). 10, the cut edges 91a, 92a each have a wavy line shape with convex portions and concave portions alternately arranged in the conveying direction MD, and if the separation distance in the conveying direction MD between the tops of two adjacent convex portions in the conveying direction MD is 1 pitch, then immediately after the dividing step (before the phase alignment of the cut edges 91a, 92a in the conveying direction MD) the cut edges 91a and 92a are shifted by 0.5 pitches in the conveying direction MD (see FIGS. 10(a) and 10(b)). In the stacking step, the phase alignment between the cut edges 91a, 92a in the conveying direction MD is eliminated, and the sheets 91, 92 are stacked together to form a continuous stack 93 in which the contours of the sheets 91, 92 match. The continuous laminate 93 has a pair of edges 93a, 93b extending in the conveying direction MD (longitudinal direction), one of which, the non-linear cut edge 93a, is formed by the overlapping portion of the non-linear cut edges 91a, 92a of both sheets 91, 92, forming a non-linear vertical direction X2 of the elastic laminate 1, and the other, linear edge 93b, is formed by the overlapping portion of the linear edges 91b, 92b of both sheets 91, 92, forming a linear vertical direction X1 of the elastic laminate 1.

[0054] The method for the phase alignment is not particularly limited, and various methods can be employed. In this embodiment, for the phase alignment, the conveyance path 910 for the first continuous sheet 91 and the conveyance path 920 for the second continuous sheet 92 are made different in length, as shown in Fig. 9. More specifically, the conveyance path 910 for the first continuous sheet 91, which is not rotated around the conveyance direction MD in the rotation step, is set longer than the conveyance path 920 for the second continuous sheet 92, so that the phases of the cut edges 91a and 92a of both sheets 91 and 92 in the conveyance direction MD are aligned at the joining position of both conveyance paths 910 and 920 (the position where the continuous laminate 93 is formed).

[0055] In the lamination step, it is preferable to overlap the first continuous sheet 91 and the second continuous sheet 92 by aligning the folded-back portions 20 of the sheets 91 and 92, that is, by aligning the linear edge portions 91b and 92b in plan view.

[0056] In the second production unit 72, after the continuous laminate 93 has been formed as described above, joints 9 (see FIG. 1) are intermittently formed in the continuous laminate 93 in the conveyance direction MD by a joining means (not shown) (joining process), and the continuous laminate 93 with the joints 9 formed therein is then cut in the direction perpendicular to the conveyance direction CD by a sheet-slicing device 99 while being conveyed in the conveyance direction MD (cutting process), thereby continuously producing sheet-shaped elastic laminates 1. The sheet-slicing device 99 is equipped with a cutting roll 990 having a cutting blade and a receiving roll 991. In the cutting process, the continuous laminate 93 is introduced between the cutting roll 990 and the receiving roll 991, and the continuous laminate 93 is cut. In the joining process, the joint 9 is formed between a pair of edges along the conveying direction MD of the continuous laminate 93, more specifically, between the edge 93a on the non-linear cut edge 91a, 92a side of both continuous sheets 91, 92 (the edge on the convex portion side of the continuous laminate 93) and the edge 93b on the linear edge (non-cut edge) 91b, 92b side of both continuous sheets 91, 92.

[0057] In the manufacturing method of the elastic laminate 1 of this embodiment, after the measurement step, based on the measurement results obtained in the measurement step, it is determined whether or not position control in the conveying direction MD of the first continuous sheet 91 and whether or not position control in the conveying direction MD of the second continuous sheet 92 is necessary, and whether or not position control of the marks 18 on the first continuous sheet 91 and whether or not position control of the marks 18 on the second continuous sheet 92 is necessary in the mark application step (determination step).

[0058] Whether or not the position of the first continuous sheet 91 in the conveying direction MD needs to be controlled is determined as follows. FIG. 12(a) shows an image in which the position P2 of the recessed portion 91c of the first continuous sheet 91 measured in the measurement process is misaligned with the center position M1 of the image of the first continuous sheet 91 captured by the first imaging device 96 in the conveying direction MD. In this case, it is determined that position control of the first continuous sheet 91 in the conveying direction MD is necessary. Specifically, the deviation L1 between the position P2 of the recessed portion 91c and the MD center position M1 of the image is calculated, and the absolute value of the deviation L1 exceeds a predetermined threshold value TL1. The threshold value TL1 can be set appropriately, for example, to 1 mm to 50 mm, preferably 5 mm to 30 mm. For example, samples (stretchable laminates) with multiple deviations L1 can be prepared in advance, and the allowable value can be determined by visual evaluation. The deviation L1 is calculated using Equation 1. L1=M1-P2 (Formula 1)

[0059] Whether or not the position of the marks 18 on the first continuous sheet 91 needs to be controlled is determined as follows. FIG. 12(b) shows an image obtained in the measurement step, in which the position P1 of the mark 18 on the first continuous sheet 91 and the position P2 of the recessed portion 91c on the first continuous sheet 91 are misaligned in the conveying direction MD. In this case, it is determined that position control of the first continuous sheet 91 in the conveying direction MD is necessary. Specifically, the deviation L2 between the position P1 of the mark 18 and the position P2 of the recessed portion 91c is calculated, and the absolute value of the deviation L2 exceeds a predetermined threshold value TL2. The threshold value TL2 can be set appropriately, for example, to 1 mm to 50 mm, preferably 5 mm to 30 mm. Specifically, samples (stretchable laminates) with multiple types of deviation L2 can be prepared in advance and visually evaluated to determine the deviation L2. The deviation L2 is calculated using Equation 2. L2=M1-P1 (Formula 2)

[0060] Whether or not the position of the second continuous sheet 92 in the conveying direction MD needs to be controlled can be determined in the same manner as whether or not the position of the first continuous sheet 91 needs to be controlled in the conveying direction MD. Furthermore, whether or not the position of the marks 18 on the second continuous sheet 92 needs to be controlled can be determined in the same manner as whether or not the position of the marks 18 on the first continuous sheet 91 needs to be controlled.

[0061] Then, based on the determination result of the determination process, the control unit 100 controls the position of the first continuous sheet 91 in the conveying direction MD in the conveying process, the position of the second continuous sheet 92 in the conveying direction MD in the conveying process, and the position at which the mark 18 is to be applied in the mark applying process, if it has been determined that control is necessary (control process). The control of the position of the first continuous sheet 91 in the conveying direction MD in the conveying process is performed by controlling the rotation speed of the first position control conveying roll 94. The control of the position of the second continuous sheet 92 in the conveying direction MD in the conveying process is performed by controlling the rotation speed of the second position control conveying roll 95. The control of the position at which the mark 18 is to be applied in the mark applying process is performed by controlling the rotation speed of the embossing roll 761.

[0062] As described above, the manufacturing method of this embodiment makes it possible to appropriately control the positions of the recessed portions 91c and marks 18 in the conveyance direction MD of the first continuous sheet 91, and the positions of the recessed portions 92c and marks 18 in the conveyance direction MD of the second continuous sheet 92. Therefore, the manufacturing method of this embodiment makes it possible to manufacture an appropriate stretchable laminate 1 in which these are arranged in appropriate positions.

[0063] In this embodiment, it is preferable to classify the determination results of the determination step into a plurality of patterns, and in the control step, to implement a control method that controls the position of the first continuous sheet 91, the position of the second continuous sheet 92, and the position where the mark 18 is applied, depending on the pattern. This point will be described in detail below. In this embodiment, there are 16 possible combinations of whether or not position control is required that are determined in the determination step, as shown in Table 1. There are 16 possible combinations of whether or not position control is required, and these 16 possible combinations can be divided into three patterns: (1) when it is necessary to control the position of the first or second continuous sheet 91, 92 in the conveying step, (2) when it is necessary to control the position at which the mark 18 is applied in the mark application step, and (3) when it is necessary to control the position of the first or second continuous sheet 91, 92 in the conveying step and also control the position at which the mark 18 is applied in the mark application step. In Table 1, "◯" means that mark 18 or recessed portions 91c, 92c are located in the appropriate position and position control is not necessary, and "×" means that mark 18 or recessed portions 91c, 92c are deviated from the appropriate position and position control is necessary. Also, in Table 1, "none" in the position control operation column means that no control is performed, "1" means that position control is performed first, and "2" means that position control is performed second.

[0064] Rather than implementing a different control method for each combination of whether or not position control is required in the determination process, the determination results in the determination process are divided into multiple patterns, and a control method corresponding to the pattern is implemented in the control process. This allows for more efficient control of the recessed portions 91c, 92c and the marks 18 in the stretchable laminate 1 to the appropriate positions. In this manufacturing method, the marking device that performs position control is positioned at different positions than the first position control transport roll and the second position control transport roll, resulting in different control systems that produce controlled results (correction of positional misalignment). Therefore, for example, if the mark position is determined to be "x" while position control of the first continuous sheet is being performed and mark position control is performed, the mark may not be controlled to the correct position. Therefore, by dividing the results into cases and specifying the control order, it is possible to stabilize the control.

[0065] Hereinafter, the position control method for each of the above cases (1) to (3) will be specifically explained using the first continuous sheet 91 as an example. (1) When it is necessary to control the position of the first or second continuous sheet 91, 92 in the conveying process. FIG. 13(a) shows an example of the case corresponding to (1) above. In the example shown in FIG. 13(a), the position P2 of the recessed portion 91c is deviated from the appropriate position, and the position of the first continuous sheet 91 needs to be controlled in the conveying process. Note that the mark 18 is located in the appropriate position. In this case, the rotation speed of the first position control conveying roll 94 is controlled based on the deviation L1 between the position P2 and the center position M1, which was used to determine whether control was necessary in the determining process. Specifically, when the position P2 is located downstream of the center position M1 in the conveying direction MD, the rotation speed of the first position control conveying roll 94 is slowed down. When the position P2 is located upstream of the center position M1 in the conveying direction MD, the rotation speed of the first position control conveying roll 94 is increased.

[0066] (2) When it is necessary to control the position where the mark 18 is applied in the mark application step FIG. 13(b) shows an example of the case corresponding to (2) above. In the example shown in FIG. 13(b), the position P1 of the mark 18 is deviated from the appropriate position, and the position at which the mark 18 is applied in the mark application step needs to be controlled. Note that the recessed portion 91c is located in the appropriate position. In this case, the position of the first position control conveyance roll 94 is controlled based on the deviation L2 between the position P1 and the position P2, which was used to determine whether control was necessary in the determination step. Specifically, when the position P1 is located downstream of the position P2 in the conveyance direction MD, the rotation speed of the embossing roll 761 is slowed down, and when the position P1 is located upstream of the position P2 in the conveyance direction MD, the rotation speed of the embossing roll 761 is increased.

[0067] (3) When it is necessary to control the position of the first or second continuous sheet 91, 92 in the conveying step and to control the position where the mark 18 is applied in the marking step. Figure 13(c) shows an example of the case that corresponds to (3) above. In the example shown in Figure 13(c), the position P2 of the recessed portion 91c is deviated from the appropriate position, and the position of the first continuous sheet 91 needs to be controlled in the conveying step. Furthermore, the position P1 of the mark 18 is also deviated from the appropriate position, and the position at which the mark 18 is applied in the marking step needs to be controlled. In this case, first, the position at which the mark 18 is applied in the marking step is controlled in the same way as in the case of (2) above. Then, the position of the first continuous sheet 91 is controlled in the conveying step in the same way as in the case of (1) above.

[0068] In this embodiment, as described above, the mark applying device 76 is an embossing device, and the control of the position at which the mark 18 is applied in the control step is preferably performed when the embossing device is not performing embossing. Specifically, it is preferable to control the position at which the mark 18 is applied by controlling the rotation speed of the embossing roll 761 when the convex portions of the embossing roll 761 are not in contact with the raw sheet 90. This prevents the rotation speed of the embossing roll 761 from changing when the convex portions of the embossing roll 761 are pressing the raw sheet 90, thereby preventing marks 18 of an unintended shape from being applied to the raw sheet 90.

[0069] In the present embodiment, the timing for capturing images of the first continuous sheet 91 and the second continuous sheet 92 in the measuring step is preferably determined based on the timing for cutting the continuous laminate 93 in the cutting step. Specifically, a proximity sensor (not shown) is installed in the sheet-forming device 99 to detect the timing for cutting the continuous laminate 93 in the cutting step. The proximity sensor is connected to a control device. The proximity sensor is also installed at a position where a cutting blade attached to the sheet-forming device 99 cuts the continuous laminate 93. The proximity sensor arranged in this manner detects the timing for cutting the continuous laminate 93 in the cutting step, and the timing for capturing images of the first and second continuous sheets 91, 92 in the measuring step can be determined based on the detected timing. Note that "based on" this timing means when the cutting blade cuts the continuous laminate 93 and the signal of the proximity sensor turns ON, when a predetermined time (delay) has elapsed since the rising edge of the signal was detected, or when the continuous laminate 93 has moved a predetermined distance since the rising edge of the signal was detected.

[0070] By determining the timing for imaging the first and second continuous sheets 91, 92 in the measurement process based on the timing for cutting the continuous laminate 93 in the cutting process, it is possible to ensure that the images captured by the first and second imaging devices 96, 97 show the portions of the first and second continuous sheets 91, 92 corresponding to the individual sheets of elastic laminate 1 to be produced.Therefore, by controlling the positions of the concave portions 91c, 92c and mark 18 based on the images, it becomes possible to more easily produce an appropriate elastic laminate 1 in which the concave portions 91c, 92c and mark 18 are arranged in the appropriate positions.

[0071] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention. For example, in the above-described embodiment, the raw sheet 90 includes sheets other than the stretch sheet 3A, but it may also be composed of only the stretch sheet 3A.

[0072] Furthermore, in the present embodiment, the marks 18 are formed by embossing the raw sheet 90, but instead, the marks 18 may be formed by printing on the raw sheet 90. In other words, the marking device 76 may be a printing device, and in the marking step, the marks 18 may be applied to the raw sheet 90 by printing on the raw sheet 90.

[0073] In this embodiment, in the marking process, marks 18 are applied to both sides of the intended cutting line CL of the raw sheet 90 in the conveying perpendicular direction CD so that both the first stretch sheet 1A and the second stretch sheet 1B each have a mark 18. Alternatively, in the marking process, marks 18 may be applied to only one of the sides of the intended cutting line CL of the raw sheet 90 in the conveying perpendicular direction CD so that only one of the first stretch sheet 1A and the second stretch sheet 1B has a mark 18.

[0074] In addition, in this embodiment, the shape of mark 18 in a plan view is circular, but the shape of mark 18 in a plan view is not limited to this and may be, for example, a triangle, a square, a rectangle, a polygon with pentagons or more, a star, a figure combining these, a letter, a character, etc.

[0075] Furthermore, in the present embodiment, the positions 91c, 92c of the recessed portions of the first continuous sheet 91 and the second continuous sheet 92 are measured in the measuring step. However, instead, the positions of the raised portions of the first continuous sheet 91 and the second continuous sheet 92 may be measured. For example, in the dividing step, the raw sheet 90 may be cut so that the cut edges of the first continuous sheet 91 and the second continuous sheet 92 each have a raised portion, and in the measuring step, the positions of the raised portions of the cut edges of both sheets 91, 92 and the positions of the marks 18 may be measured. Specifically, a portion of the first or second continuous sheet 91, 92 containing the raised portion may be registered in advance as a partial image, and the position of the raised portion may be measured by searching for a portion that matches the partial image using a pattern matching method. The position of the recessed portion may be measured for one of the first continuous sheet 91 and the second continuous sheet 92, and the position of the raised portion may be measured for the other, and the phases of both continuous sheets may be aligned so that the raised portions or the recessed portions match. [Explanation of symbols]

[0076] 1 Stretchable laminate 1A First Elastic Sheet 1B Second elastic sheet 2. Exterior body 20 Folded section 21 Non-existent folded section 22 Boundary between folded portion and reinforcing sheet (third raw material sheet) 3,3A Outer layer sheet (stretchable sheet) 31,32 Fiber sheet 33 Elastic Filament 4. Inner layer sheet (first raw material sheet) 5 Reinforcing sheet (third raw material sheet) 6 Functional sheet (fourth raw material sheet) 7 Target tape (second raw material sheet) 8 Elastic member 9 Joint 10. Pants-type disposable diapers 11 Absorbent pad section 12 Surface sheet 13 Back sheet 14 absorbent core 15 Leak proof cuff 16 Fastening tape 17 Holder part 18 marks 70 Elastic laminate manufacturing equipment 71 1st Manufacturing Department 72 2nd Manufacturing Department 73 Joining means 74 Cutting means 75 Seat rotation area 80 Raw sheet precursor 90 raw sheet 91 First consecutive sheet 91a Cut edge of first continuous sheet 92 Second consecutive sheet 92a Cut edge of second continuous sheet 93 Continuous laminate CL cutting line

Claims

1. A method for producing a stretchable laminate, comprising: a first stretchable sheet having stretchability in one direction; and a second stretchable sheet overlaid on one side of the first stretchable sheet and having stretchability in the one direction; both stretchable sheets are joined to each other at a pair of joining sections formed at both ends in the one direction; the two stretchable sheets are not joined to each other at a portion sandwiched between the pair of joining sections; and the portion sandwiched between the pair of joining sections can form a ring-shaped structure having stretchability in the circumferential direction, a marking step of applying a mark to a continuous band-like stretchable raw sheet that is continuous in one direction and stretched in the one direction, while conveying the raw sheet in the one direction as a conveying direction, using a marking device; a dividing step of dividing the raw sheet to which the marks have been applied into two equal parts in a direction perpendicular to the conveyance direction, and cutting the raw sheet along a planned cutting line that meanders symmetrically with respect to a center line extending parallel to the conveyance direction, thereby dividing the raw sheet into a first continuous sheet in which a plurality of first stretchable sheets are connected in the conveyance direction, and a second continuous sheet in which a plurality of second stretchable sheets are connected in the conveyance direction; a rotating step of rotating one or both of the first and second continuous sheets around the conveyance direction while conveying the first and second continuous sheets in the conveyance direction so that the cut edges of the first and second continuous sheets at the intended cutting lines face the same direction; a conveying step of conveying the first continuous sheet by first position-controlled conveying rolls and conveying the second continuous sheet by second position-controlled conveying rolls; a measuring step of imaging the first continuous sheet with a first imaging device and the second continuous sheet with a second imaging device, and measuring, from the images obtained by imaging, the positions of the concave or convex portions of the cut edges of the first continuous sheet and the second continuous sheet in the conveying direction, as well as the position of the mark provided on the first continuous sheet or the second continuous sheet; a lamination step of overlapping the first continuous sheet and the second continuous sheet such that the cut edge portions of the two continuous sheets are aligned in phase with each other in the conveying direction to obtain a continuous laminate; a joining step of intermittently forming the joint portions on the continuous laminate in the conveying direction; a cutting step of cutting the continuous laminate in the conveyance direction orthogonal to form the elastic laminate into individual sheets; a determining step of determining, based on the measurement results obtained in the measuring step, whether or not position control of the first continuous sheet in the conveying direction is necessary and whether or not position control of the second continuous sheet in the conveying direction is necessary, and whether or not position control of the marks on the first continuous sheet and the second continuous sheet is necessary in the marking step; and a control step of controlling, based on the determination result of the determination step, the position of the first continuous sheet in the conveying direction in the conveying step, the position of the second continuous sheet in the conveying direction, and the position at which the mark is applied in the marking step, which are determined to require control.

2. The determination result of the determination step is classified into a plurality of patterns; 2. The method for producing a stretchable laminate according to claim 1, wherein the control step implements a control method for controlling the position of the first continuous sheet, the position of the second continuous sheet, and the position at which the mark is applied, in accordance with the pattern.

3. The method for producing a stretchable laminate according to claim 1 or 2, wherein the timing for capturing images of the first continuous sheet and the second continuous sheet in the measuring step is determined based on the timing for cutting the continuous laminate in the cutting step.

4. 3. The method for producing an elastic laminate according to claim 1 or 2, wherein the measurement of the positions of the cut edges of the first continuous sheet and the second continuous sheet at the planned cutting lines in the conveying direction and the positions of the marks applied to the first continuous sheet and the second continuous sheet in the measuring step is performed by searching for pre-registered partial images of the first continuous sheet and the second continuous sheet cut in the dividing step from the images obtained by the imaging using a pattern matching method.

5. the marking device is an embossing device; The method for producing a stretchable laminate according to claim 1 or 2, wherein the marking step comprises embossing the raw sheet to provide the mark on the raw sheet.

6. The method for producing a stretchable laminate according to claim 5 , wherein the control of the position at which the mark is applied in the control step is performed when the embossing device is not performing embossing.

7. the marking device is a printing device; The method for producing a stretchable laminate according to claim 1 or 2, wherein the marking step includes printing the raw sheet to provide the mark on the raw sheet.

Images