Method for manufacturing a composite stretchable sheet, and apparatus for manufacturing a composite stretchable sheet

Abstract

To efficiently manufacture composite stretchable sheets of varying lengths according to the size of the absorbent material. [Solution] A method for continuously manufacturing a first composite stretchable sheet having a first pitch or a second composite stretchable sheet having a second pitch in the conveying direction, wherein the first composite stretchable sheet is provided with stretch reduction regions (LE) at each first pitch, and the second composite stretchable sheet is provided with the same stretch reduction regions (LE) at each second pitch, and comprises a sheet joining process (S203) for joining stretchable sheets (22, 23) and a non-stretchable sheet (21), and a stretch reduction process (S204) for forming stretch reduction regions (LE) at each first or second pitch in the conveying direction, wherein the pattern roll (241) rotates once to form a stretch reduction region (LE) while the first composite stretchable sheet is conveyed by the first pitch, and the pattern roll (241) rotates once to form a stretch reduction region (LE) while the second composite stretchable sheet is conveyed by the second pitch.

Description

Technical Field

[0003]

[0001] The present invention relates to a method for manufacturing a composite stretchable sheet and a composite stretchable sheet manufacturing apparatus.

Background Art

[0002] Conventionally, as a material for absorbent articles such as diapers, a composite stretchable sheet (web) formed by laminating a plurality of sheet members including a stretchable sheet is known. In such a stretchable composite sheet, a stretch reduction treatment may be performed in order to reduce the stretchability of a portion overlapping with an absorbent body (absorbent). For example, Patent Document 1 discloses a technique for reducing the stretchability of a stretchable sheet by forming a plurality of slits in a predetermined region of the stretchable sheet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When reducing the stretchability of a composite stretchable sheet, conventionally, it has been common to perform a joining process for joining a plurality of laminated sheets and a stretch reduction process using a single roller (pattern roll). In this method, when manufacturing diapers (absorbent articles) of different sizes, it is necessary to replace (so-called setup change) the rollers adjusted for each different size, making efficient manufacturing difficult.

[0005] The present invention has been made in view of the above problems, and an object thereof is to efficiently manufacture composite stretchable sheets having different lengths according to the size of an absorbent article.

Means for Solving the Problems

[0006] The main invention for achieving the above objective is a method for continuously manufacturing a first composite stretchable sheet having a first pitch in the transport direction or a second composite stretchable sheet having a second pitch in the transport direction, wherein the first composite stretchable sheet is provided with stretch reduction regions where the stretch stress is reduced at each of the first pitches, and the second composite stretchable sheet is provided with the stretch reduction regions at each of the second pitches, and the method comprises a transport process of transporting the stretchable sheet and a non-stretchable sheet different from the stretchable sheet along the transport direction, a sheet joining process of joining the stretchable sheet and the non-stretchable sheet, which have been stretched along the transport direction, in a state where they are laminated in the thickness direction, and at each of the first pitch or second pitches in the transport direction A method for manufacturing a composite stretchable sheet, comprising: a stretching reduction process for forming the stretching reduction region, wherein the stretching reduction region is formed by a stretching reduction mechanism comprising a pattern roll and a horn or anvil roll facing the pattern roll with the composite stretchable sheet in between, and the sheet joining process is performed by a sheet joining mechanism positioned spaced upstream of the pattern roll in the conveying direction, wherein when manufacturing the first composite stretchable sheet, the pattern roll rotates once to form the stretching reduction region while the first composite stretchable sheet is conveyed by a first pitch in the conveying direction, and when manufacturing the second composite stretchable sheet, the pattern roll rotates once to form the stretching reduction region while the second composite stretchable sheet is conveyed by a second pitch. Other features of the present invention will be made clearer by description in this specification and the accompanying drawings. [Effects of the Invention]

[0007] According to the present invention, it is possible to efficiently manufacture composite stretchable sheets of different lengths depending on the size of the absorbent article. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view showing one example of the configuration of menstrual panties 1. [Figure 2] This is a schematic plan view of menstrual panties 1 in their unfolded and stretched state, as seen from the skin side in the thickness direction. [Figure 3] Figure 2 is a schematic diagram of the AA section. [Figure 4] This is a plan view illustrating an example of the arrangement of the sheet joint portion 91 and the expansion / contraction reduction portion 92 provided on the exterior member 20. [Figure 5] This is a flowchart illustrating the manufacturing process of menstrual panties 1. [Figure 6] This is a conceptual diagram illustrating the manufacturing process of menstrual panties 1. [Figure 7] This is a flowchart of each process performed in the exterior component forming process S102. [Figure 8] This diagram illustrates the configuration of a manufacturing apparatus 200 for forming the exterior component 20. [Figure 9] This diagram illustrates the stretching process using the stretching mechanism 220. [Figure 10] Figures 10A and 10B illustrate the sheet joining mechanism 230. [Figure 11] Figures 11A and 11B illustrate the expansion / contraction reduction mechanism 240. [Figure 12] This is a diagram illustrating the manufacturing process of menstrual panties of different sizes. [Figure 13] Figures 13A and 13B illustrate the behavior in the expansion / contraction reduction process S204 when the transport speed of the exterior member 20 and the rotation speed of the pattern roll 241 are different. [Figure 14] Figures 14A and 14B illustrate the behavior in the expansion / contraction reduction process S204 when the transport speed of the exterior member 20 and the rotation speed of the pattern roll 241 are different. [Figure 15] This figure illustrates the rotation speed of the pattern roll 241 in a modified example of the stretch reduction process S204. [Figure 16] This is a schematic cross-sectional view of the unfolded and stretched sanitary shorts 2, seen from one side in the left-right direction. [Figure 17] It is a diagram for explaining the configuration of a manufacturing apparatus 200 for forming an exterior member 20 of a sanitary short 2. [Figure 18] It is a diagram for explaining a modification example of the stretch reduction mechanism 240.

Mode for Carrying Out the Invention

[0009] At least the following matters become clear from the description in this specification and the accompanying drawings.

[0010] (Aspect 1) A method for continuously manufacturing a first composite stretchable sheet formed by laminating a plurality of sheets including at least a stretchable sheet and having a first pitch in the transport direction or a second composite stretchable sheet having a second pitch in the transport direction, wherein the first composite stretchable sheet is provided with a stretch reduction region in which stretch stress is reduced for each first pitch, the second composite stretchable sheet is provided with the stretch reduction region for each second pitch, a transport process of transporting the stretchable sheet and a non-stretchable sheet different from the stretchable sheet along the transport direction, a sheet joining process of joining the stretchable sheet stretched along the transport direction and the non-stretchable sheet in a state of being laminated in the thickness direction, and a stretch reduction process of forming the stretch reduction region for each first pitch or the second pitch in the transport direction, and forming the stretch reduction region by a stretch reduction mechanism including a pattern roll and a horn or anvil roll facing the pattern roll with the composite stretchable sheet interposed therebetween, and performing the sheet joining process by a sheet joining mechanism disposed upstream of the pattern roll in the transport direction, and when manufacturing the first composite stretchable sheet, the pattern roll rotates once to form the stretch reduction region while the first composite stretchable sheet is transported by the first pitch in the transport direction, and when manufacturing the second composite stretchable sheet, the pattern roll rotates once to form the stretch reduction region while the second composite stretchable sheet is transported by the second pitch. A method for manufacturing a composite stretchable sheet, characterized by the above.

[0011] According to the method for manufacturing a composite stretchable sheet of Mode 1, while a continuum of the composite stretchable sheet (for example, used as an exterior member of an absorbent article) is conveyed by a pitch corresponding to one piece of each size, the rotation of the pattern roll is controlled so that the pattern roll rotates once to form a stretch reduction region. Thereby, it becomes possible to form a stretch reduction region for each pitch with respect to a composite stretchable sheet having a certain pitch (size) without replacing the pattern roll. That is, since it becomes possible to manufacture a plurality of types of composite stretchable sheets having different sizes using the same pattern roll, it is possible to efficiently manufacture stretchable composite sheets (exterior members of absorbent articles) having different lengths (pitches) without performing setup change of the manufacturing apparatus.

[0012] (Mode 2) The method for manufacturing a composite stretchable sheet according to Mode 1, wherein the stretchable sheet is a stretchable nonwoven fabric and the non-stretchable sheet is a non-stretchable nonwoven fabric.

[0013] According to the method for manufacturing a composite stretchable sheet of Mode 2, since nonwoven fabrics are used for both the stretchable sheet and the non-stretchable sheet, the air permeability is higher than the case of using a resin film or the like, and it is easy to realize a good touch. Furthermore, since it has high flexibility and is difficult to break, it is suitable for use as a wearing article such as an absorbent article. In addition, by forming a stretch reduction portion, it is easy to locally adjust the stretchability. Thereby, it becomes possible to manufacture a composite stretchable sheet having stretchability with a minimum configuration while achieving both air permeability, flexibility, touch, and strength.

[0014] (Mode 3) The method for manufacturing a composite stretchable sheet according to Mode 1 or 2, wherein a stretching process for imparting stretchability along the conveyance direction is performed on the stretchable sheet before the sheet joining process.

[0015] According to the composite stretchable sheet manufacturing method of Embodiment 3, preparations such as procuring stretchable sheets in advance are unnecessary, and the base material can be treated as a non-stretchable sheet until the stretching process is carried out, making it easy to handle when manufacturing the composite stretchable sheet. Furthermore, by using a stretching mechanism, stretchability can be stably imparted to a non-stretchable nonwoven fabric.

[0016] (Aspect 4) The method for manufacturing a composite stretchable sheet according to Embodiment 1, wherein the stretchable sheet is a stretchable film, the non-stretchable sheet is a non-stretchable nonwoven fabric, and in the sheet joining process, the non-stretchable sheet is joined to both sides of the stretchable sheet in the thickness direction.

[0017] According to the composite stretchable sheet manufacturing method of Embodiment 4, since the stretchable sheet is not exposed to the outside and both sides in the thickness direction are composed of non-stretchable nonwoven fabric, it is possible to form a composite stretchable sheet with enhanced texture and strength. Furthermore, by changing the arrangement and configuration of the stretchable sheet, the stretchability characteristics (strength of stretchability and range of stretchability) can be easily adjusted, and a variety of composite stretchable sheets can be formed according to the application.

[0018] (Appendix 5) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 4, wherein the stretch reduction region is formed in the portion that overlaps with the sheet joint formed in the sheet joining process when viewed in the thickness direction.

[0019] According to the composite stretchable sheet manufacturing method of Embodiment 5, a stretchable sheet and a non-stretchable sheet are joined via a sheet joint to provide stretchability, thereby partially reducing the stretchability in a portion of the area where stretchability is imparted. In other words, by allowing stretchability to be exhibited throughout the entire area where the stretchable sheet and the non-stretchable sheet are joined, while reducing the stretchability in a portion of that area, it becomes easier to efficiently manufacture composite stretchable sheets of different sizes.

[0020] (Aspect 6) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 5, wherein the sheet joining mechanism can change the range in which the stretchable sheet and the non-stretchable sheet are joined in an intersecting direction perpendicular to the conveying direction, and the stretch reduction mechanism can change the range in which the stretch reduction region is formed in the intersecting direction.

[0021] According to the composite stretchable sheet manufacturing method of Embodiment 6, even if the sizes of the composite stretchable sheets differ not only in the conveying direction but also in the intersecting direction, the manufacturing equipment can be shared. Therefore, it is possible to efficiently manufacture stretchable composite sheets of different sizes in the longitudinal direction (intersecting direction) and the left-right direction (conveying direction) without changing the equipment.

[0022] (Aspect 7) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 6, wherein the stretch reduction treatment is performed by sealing and ultrasonic welding.

[0023] According to the composite stretchable sheet manufacturing method of Embodiment 7, since the stretchable sheet and the non-stretchable sheet are sealed and joined using ultrasonic welding means rather than heat welding means, edge breakage due to heat is less likely to occur, and a stable stretch reduction region can be formed while suppressing the thermal impact on the stretchable sheet.

[0024] (Pattern 8) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 7, wherein in the sheet joining process, seal joining and ultrasonic welding are performed, the stretchable sheet is a stretchable nonwoven fabric, and the ultrasonic welding is performed from the side facing the stretchable sheet in the thickness direction.

[0025] According to the composite stretchable sheet manufacturing method of Embodiment 8, when performing the sheet joining process, a non-stretchable sheet that does not contain stretchable fibers is wrapped around the outer surface of a pattern roll, and then a stretchable sheet is wrapped over the non-stretchable sheet, and ultrasonic vibrations are applied from the side facing the stretchable sheet. This prevents the stretchable fibers contained in the stretchable sheet from getting caught on the surface (outer surface) of the pattern roll, and allows the two sheets to be joined while stably conveying the non-stretchable sheet and the stretchable sheet.

[0026] (Aspect 9) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 8, wherein the speed at which the stretchable sheet and the non-stretchable sheet, which are stacked in the thickness direction, are conveyed in the conveying direction is different from the speed at which the pattern roll rotates.

[0027] According to the composite stretchable sheet manufacturing method of Embodiment 9, even if the rotation speed of the pattern roll and the conveying speed of the composite stretchable sheet are different, the speed difference is easily absorbed as the composite stretchable sheet expands and contracts in the conveying direction. Furthermore, since the composite stretchable sheet expands and contracts along the conveying direction in response to the rotation of the pattern roll, slippage between the sheet and the pattern roll is less likely to occur. Therefore, expansion reduction regions can be stably formed at different pitches depending on the size of the composite stretchable sheet to be manufactured.

[0028] (Aspect 10) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 9, wherein, when forming the stretch reduction region, the pattern roll rotates such that, in the conveying direction, the stretch ratio per unit length of the stretchable sheet and the non-stretchable sheet upstream of the pattern roll is different from the stretch ratio per unit length of the stretchable sheet and the non-stretchable sheet downstream of the pattern roll.

[0029] According to the composite stretchable sheet manufacturing method of embodiment 10, for example, even when the rotation speed of the pattern roll is faster than the conveying speed of the composite stretchable sheet, by forming a stretch reduction region while tension is applied to the stretchable composite stretchable sheet downstream in the conveying direction, it is easy to stably form a stretch reduction region equivalent to that when the conveying speed of the composite stretchable sheet and the rotation speed of the pattern roll are the same. Similarly, even when the rotation speed of the pattern roll is slower than the conveying speed of the composite stretchable sheet, it is easy to stably form a stretch reduction region. Therefore, it is easy to form a constant range of the stretch reduction region in the conveying direction.

[0030] (Aspect 11) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 10, wherein, when forming the stretch-reducing region, the stretchable sheet and the non-stretchable sheet are not wrapped around the outer surface of the pattern roll.

[0031] According to the composite stretchable sheet manufacturing method of Embodiment 11, the composite stretchable sheet is not wrapped around the outer surface of the pattern roll of the stretch reduction mechanism, and frictional force is less likely to act between the composite stretchable sheet and the outer surface of the pattern roll. Therefore, when forming the stretch reduction region, the composite stretchable sheet is prevented from being pulled excessively strongly upstream or downstream in the conveying direction. As a result, even when the conveying speed of the composite stretchable sheet and the rotation speed of the pattern roll are different, it is easier to stably form the stretch reduction region at predetermined pitches.

[0032] (Aspect 12) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 11, wherein a third composite stretchable sheet having a third pitch that is intermediate in length between the first pitch and the second pitch in the conveying direction, and the length of the pattern roll in the circumferential direction is the same as the length of the third pitch.

[0033] According to the composite stretchable sheet manufacturing method of embodiment 12, since the circumferential length (perimeter) of the pattern roll is determined based on an intermediate-sized pitch (third pitch), when manufacturing small-sized and large-sized products, the difference between the first pitch (small size) and the second pitch (large size) is less likely to become excessively large, making it easier to form a stretch-reduction area with more stable operation according to each size.

[0034] (Aspect 13) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 12, wherein, in the transport direction, the length of the stretching reduction region is 1 / 2 or less of the shorter of the first pitch and the second pitch.

[0035] According to the composite stretchable sheet manufacturing method of embodiment 13, the section in which the composite stretchable sheet is sandwiched between the pattern plate and the ultrasonic horn during one rotation of the pattern roll does not become excessively long, and the composite stretchable sheet is less likely to be pulled in the conveying direction. Therefore, even when the conveying speed of the composite stretchable sheet and the rotation speed of the pattern roll are different, it is easy to stably form a stretch reduction region.

[0036] (Aspect 14) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 13, wherein the rotational speed of the pattern roll is periodically varied, and at least when forming the stretchable / non-stretchable region, the speed at which the stretchable sheet and the non-stretchable sheet are conveyed in the conveying direction is the same as the rotational speed of the pattern roll.

[0037] According to the composite stretchable sheet manufacturing method of embodiment 14, the rotation speed of the pattern roll at the timing of forming the stretch reduction region can be matched to the transport speed of the composite stretchable sheet, and it is possible to accurately rotate the pattern roll once while the composite stretchable sheet is transported by one pitch. As a result, the stretch reduction region is formed with high precision in the transport direction and is formed at even intervals without variation.

[0038] (Aspect 15) A method for manufacturing a composite stretchable sheet according to any one of embodiments 1 to 14, wherein the stretch reduction region is formed by cuts or openings in the stretch reduction treatment.

[0039] According to the composite stretchable sheet manufacturing method of Embodiment 15, the stretchability is reduced by forming openings in the stretchable nonwoven fabric or stretchable film, making the composite stretchable sheet less prone to twisting or hardening as a whole, and improving the feel against the skin when used as a wearable item.

[0040] (Aspect 16) A composite stretchable sheet manufacturing apparatus for continuously producing a first composite stretchable sheet having a first pitch in the conveying direction or a second composite stretchable sheet having a second pitch in the conveying direction, wherein the first composite stretchable sheet is provided with stretch reduction regions where the stretch stress is reduced at each of the first pitches, and the second composite stretchable sheet is provided with the stretch reduction regions at each of the second pitches, a conveying mechanism for conveying the stretchable sheet and a non-stretchable sheet different from the stretchable sheet along the conveying direction, a sheet joining mechanism for joining the stretchable sheet and the non-stretchable sheet, which have been stretched along the conveying direction, in a state where they are stacked in the thickness direction, and the first pitch or A composite stretchable sheet manufacturing apparatus comprising: a stretch reduction mechanism that forms the stretch reduction region at each second pitch, wherein the stretch reduction mechanism comprises a pattern roll and a horn or anvil roll facing the pattern roll with the composite stretchable sheet in between, the sheet joining mechanism is positioned spaced upstream of the pattern roll in the conveying direction, and when manufacturing the first composite stretchable sheet, the pattern roll rotates once to form the stretch reduction region while the first composite stretchable sheet is conveyed by a first pitch in the conveying direction, and when manufacturing the second composite stretchable sheet, the pattern roll rotates once to form the stretch reduction region while the second composite stretchable sheet is conveyed by a second pitch.

[0041] According to the composite stretchable sheet manufacturing apparatus of embodiment 16, the rotation of the pattern roll is controlled so that while a continuous body of composite stretchable sheets (for example, used as an outer covering for absorbent articles) is conveyed by a pitch equivalent to one piece of each size, the pattern roll completes one rotation to form a stretch reduction region. This makes it possible to form a stretch reduction region for each pitch of a composite stretchable sheet having a certain pitch (size) without changing the pattern roll. In other words, it is possible to manufacture multiple types of composite stretchable sheets of different sizes using the same pattern roll, and thus it is possible to efficiently manufacture stretchable composite sheets (outer coverings for absorbent articles) of different lengths (pitches) without changing the setup of the manufacturing apparatus.

[0042] ===First Embodiment=== As an example of the use of the composite stretchable sheet according to the first embodiment of the present invention, a panty-type absorbent article using the composite stretchable sheet as an outer material will be described. Note that panty-type absorbent articles include sanitary shorts, panty-type sanitary napkins, panty-type diapers, etc. Hereinafter, panty-type absorbent articles will also be referred to as "sanitary shorts 1".

[0043] <Basic structure of menstrual panties 1> Figure 1 is a schematic perspective view showing one example of the configuration of the sanitary shorts 1 according to this embodiment. Figure 2 is a schematic plan view of the sanitary shorts 1 in an unfolded and stretched state, viewed from the skin side in the thickness direction. Figure 3 is a schematic cross-sectional view of AA of Figure 2.

[0044] Furthermore, the "stretched state" of the sanitary shorts 1 refers to the state in which the entire sanitary shorts 1 (the entire product) is stretched without wrinkles by stretching each elastic component of the sanitary shorts 1 (for example, the skin-side sheets 22, 23, etc., described later). Specifically, it refers to the state in which the dimensions of each component constituting the sanitary shorts 1 (for example, the outer component 20, etc., described later) are stretched to match or be close to the dimensions of the individual component.

[0045] The sanitary shorts 1, in the panty-type state shown in Figure 1, have mutually orthogonal "up-down direction," "left-right direction," and "front-back direction." Furthermore, as shown in Figure 3, they also have a "thickness direction," which is the direction in which each component is stacked. Within the up-down direction, the side facing the wearer's torso when wearing the sanitary shorts 1 is defined as the "upper side," and the side facing the wearer's crotch is defined as the "lower side." Within the front-back direction, the side facing the wearer's abdomen when wearing the shorts is defined as the "front side," and the side facing the wearer's back is defined as the "back side." Within the thickness direction, the side that comes into contact with the wearer's skin when wearing the sanitary shorts 1 is defined as the "skin side," and the opposite side is defined as the "non-skin side."

[0046] Furthermore, in the unfolded state shown in Figure 2, the sanitary shorts 1 have a "vertical direction" and a "horizontal direction" that are orthogonal to each other. The "vertical direction" is the direction along the up and down direction in the panty type, and the "horizontal direction" is the direction along the left and right direction in the panty type.

[0047] The sanitary shorts 1 comprises an absorbent body 10 that absorbs excretory fluids (liquids) such as menstrual blood, and an outer material 20 that is positioned on the non-skin side of the absorbent body 10 and is positioned around the wearer's waist when the sanitary shorts 1 are worn.

[0048] (Absorbent body 10) As shown in Figure 2, the absorbent body 10 has a roughly rectangular shape in plan view, with its vertical direction (i.e., the longitudinal direction of the absorbent body 10) aligned with the vertical direction of the sanitary shorts 1. As shown in Figures 2 and 3, the absorbent body 10 has an absorbent core 11 aligned in the vertical direction (up and down direction), a top sheet 12 positioned closer to the skin than the absorbent core 11, a second sheet 13 positioned between the top sheet 12 and the absorbent core 11, a back sheet 14 positioned closer to the skin than the absorbent core 11, and a side sheet 15 positioned on the side of the back sheet 14 that is not touching the skin.

[0049] The absorbent core 11 is a component that absorbs and retains liquids such as menstrual blood, and is formed from liquid-absorbing fibers such as pulp fibers. The absorbent core 11 may also be made of pulp fibers mixed with a superabsorbent polymer (SAP). Furthermore, its outer surface may be covered with a liquid-permeable sheet material (core wrap sheet) such as tissue paper or nonwoven fabric.

[0050] The top sheet 12 is a liquid-permeable sheet material that can come into contact with the wearer's skin when worn, and is formed from, for example, a hydrophilic air-through nonwoven fabric or a spunbond nonwoven fabric.

[0051] The second sheet 13 is a sheet member having almost the same function and structure as the top sheet 12, and is laminated on the non-skin side of the top sheet 12. Note that the second sheet 13 is not necessarily required in the absorbent body 10.

[0052] The backsheet 14 is a liquid-impermeable and breathable sheet member (breathable sheet member) that prevents liquids such as menstrual blood absorbed by the absorbent core 11 from leaking out to the outside, and is formed from, for example, a resin film.

[0053] The side sheet 15 is a sheet member laminated on the non-skin side of the back sheet 14, and is made of a hydrophobic nonwoven fabric such as SMS (spunbond-meltblown-spunbond) nonwoven fabric. The left and right ends of the side sheet 15 form a pair of leak-proof walls 30. The leak-proof walls 30 are provided in pairs on both sides of the absorbent body 10 in the lateral (left-right) direction and correspond to so-called three-dimensional gathers. When the sanitary shorts 1 are worn, the leak-proof walls 30 stand up on the skin side of the absorbent body 10 on both sides in the left-right direction, thereby preventing menstrual blood and other excretory fluids from leaking out to the outside of the absorbent body 10 in the left-right direction along the wearer's skin.

[0054] Furthermore, the absorbent body 10 may be provided with multiple absorbent elastic members 50 that stretch along the vertical direction (up and down direction). The absorbent elastic members 50 are formed, for example, from elastic thread and are positioned on the non-skin side of the absorbent core 11 (between the back sheet 14 and the side sheet 15 in Figure 3) in a state stretched vertically (up and down direction) at a predetermined stretch ratio. In the sanitary shorts 1 of this embodiment, as shown in Figure 2, four absorbent elastic members 50 are provided at predetermined intervals in the left-right direction. The elasticity exhibited by the absorbent elastic members 50 allows the absorbent body 10 to stretch along the vertical direction, making it easier for the absorbent body 10 to fit the wearer's crotch area when the sanitary shorts 1 are worn, thereby improving the absorbency of menstrual blood and other excretory fluids. The arrangement, number, and stretch ratio of the absorbent elastic members 50 can be changed as appropriate.

[0055] (Exterior component 20) The outer casing member 20 is a member positioned on the non-skin side of the absorbent body 10, and is a composite stretchable sheet with stretchability in the left-right direction, formed by laminating a non-skin side sheet 21 and skin side sheets 22 and 23 in the thickness direction. Furthermore, as shown in Figure 2, the portion of the outer casing member 20 that overlaps with the side joint 60 formed on the front side (front side in the front-rear direction in Figure 1) in the longitudinal direction is defined as the front waist portion FA. Similarly, the portion of the outer casing member 20 that overlaps with the side joint 60 formed on the rear side (rear side in the front-rear direction in Figure 1) in the longitudinal direction is defined as the rear waist portion BA. Then, the portion between the rear end of the front waist portion FA and the front end of the rear waist portion BA in the longitudinal direction is defined as the crotch area CA.

[0056] The non-skin-facing sheet 21 is a non-stretchable sheet material positioned on the non-skin-facing side of the sanitary shorts 1, and is formed from, for example, spunbond nonwoven fabric or SMS nonwoven fabric. In this embodiment, as shown in Figure 2, the non-skin-facing sheet 21 has a shape that is constricted inward in the left-right direction at the crotch area CA. The term "non-stretchable sheet material" refers to a sheet material that does not contain elastic fibers such as polyurethane and has not undergone stretching treatment like the elastic sheets (skin-facing sheets 22, 23) described later. For example, the spunbond nonwoven fabric and SMS nonwoven fabric mentioned above are formed by the entanglement of multiple fibers and do not have the property of stretching or shrinking significantly during normal use, and are treated as non-stretchable sheets in this embodiment.

[0057] The skin-side sheet 22 is an elastic sheet member laminated on the skin side of the non-skin-side sheet 21 on the longitudinal front (abdominal) side (see Figure 3), and in the sanitary shorts 1, it exhibits elasticity along the left-right direction. The skin-side sheet 22 is formed, for example, from an elastic nonwoven fabric. An "elastic nonwoven fabric" is a nonwoven fabric that includes elastic fibers and stretchable fibers with lower shrinkage than elastic fibers, and has been subjected to appropriate stretching treatment such as gear stretching. In this embodiment, the skin-side sheet 22 can use polyurethane elastomer fibers, which are a type of thermoplastic elastomer with elasticity, as the elastic fibers, and polypropylene (PP) fibers, which are a type of thermoplastic resin with inelasticity, as the stretchable fibers. The elastic nonwoven fabric is formed by a stretching treatment (S202) described later (see Figure 7).

[0058] The skin-side sheet 23 is an elastic sheet member laminated on the skin side of the non-skin-side sheet 21 on the rear (back) side in the longitudinal direction, and has the same configuration as the skin-side sheet 22.

[0059] The skin-side sheets 22 and 23 are joined to the non-skin-side sheet 21 by a plurality of sheet joining portions 91 scattered throughout the entire surface of the skin-side sheets 22 and 23, thereby providing the portion of the exterior member 20 on which the skin-side sheets 22 and 23 are provided with lateral stretchability. In other words, the exterior member 20 is a stretchable composite sheet formed by laminating a plurality of sheets (skin-side sheets 22 and 23 and the non-skin-side sheet 21), including at least the stretchable sheets (skin-side sheets 22 and 23). The sheet joining portions 91 are formed using known joining means such as ultrasonic welding in a sheet joining process (S203) described later (see Figure 7).

[0060] Furthermore, when viewed in the thickness direction, at least a portion of the area of ​​the skin-side sheets 22 and 23 that overlaps with the absorbent main body 10 is provided with a stretch-reducing portion 92. In the area where the stretch-reducing portion 92 is provided, the stretchability of the skin-side sheets 22 and 23 is reduced. The stretch-reducing portion 92 is formed by a stretch-reducing treatment (S204) described later (see Figure 7).

[0061] Figure 4 is a plan view illustrating an example of the arrangement of the sheet joint portion 91 and the expansion / contraction reduction portion 92 provided on the exterior member 20. Figure 4 shows the state in which the base sheets (non-skin side sheet 21 and skin side sheets 22, 23) constituting the exterior member 20 are joined in the thickness direction by the sheet joint portion 91 when unfolded and extended. The joining of the non-skin side sheet 21 and the skin side sheets 22, 23 (sheet joining process S203, described later) is performed before the leg opening 1b is formed in the exterior member 20. Therefore, Figure 4 shows the exterior member 20 before the cutting (shown by dashed lines in Figure 4) for forming the leg opening 1b is performed.

[0062] In Figure 4, when the outer casing member 20 is viewed in the thickness direction in its unfolded and extended state, the area indicated by the shaded portion where the outer casing member 20 and the absorbent body 10 overlap is designated as region Y, and the remaining area is designated as region X. In the sanitary shorts 1, a sheet joint portion 91 is formed in region X, and a stretch-reducing portion 92 is formed in region Y. That is, both the sheet joint portion 91 and the stretch-reducing portion 92 are formed in region Y. Hereinafter, the region where the stretch-reducing portion 92 is formed (region Y in Figure 4) will also be called the "stretch-reducing region LE". In the part of the outer casing member 20 where the stretch-reducing region LE is provided (i.e., the part where the absorbent body 10 is placed), the stretchability of the skin-side sheets 22 and 23 is reduced. Therefore, the absorbent body 10 does not contract in the left-right direction, which would worsen the fit and liquid absorption when the sanitary shorts 1 are worn.

[0063] As shown in the enlarged view of Figure 4, the sheet joint portion 91 of the sanitary shorts 1 is formed by a number of dot-shaped welded portions arranged in a roughly grid pattern. In particular, by providing multiple sheet joint portions 91 at intervals in the lateral direction (left-right direction), the non-skin-side sheet 21 can be joined to the skin-side sheet 22, 23 without impairing the lateral elasticity of the skin-side sheets 22, 23. Note that the shape and arrangement of individual sheet joint portions 91 are not limited to the example in Figure 4 and can be changed as appropriate. Also, the sheet joint portions 91 do not necessarily have to be formed over the entire region X. For example, in the outer material 20, sheet joint portions 91 may not be provided in the portion where the non-skin-side sheet 21 and the skin-side sheets 22, 23 do not overlap and the material consists of only one layer of sheet material.

[0064] The stretch reduction section 92 is formed by a plurality of slit-shaped grooves arranged along the vertical direction, as shown in Figure 4. These slit-shaped grooves may also be cuts or openings that penetrate the skin-side sheets 22 and 23 in the thickness direction. In the areas where such grooves are formed, the elastic fibers constituting the skin-side sheets 22 and 23 are cut, making it difficult for the fibers to harden, and thus reducing the stretchability of the skin-side sheets 22 and 23 in the left-right direction without worsening the feel against the skin. Alternatively, the stretchability of the skin-side sheets 22 and 23 in the left-right direction may be reduced by a configuration other than grooves. For example, in region Y, multiple welded portions may be formed that have a larger individual area than the sheet joint section 91 (welded portion) formed in region X and are densely arranged. In other words, the total area of ​​the expansion / contraction reducing portions 92 provided per unit area in region Y (hereinafter also referred to as the "area ratio") may be greater than the total area of ​​the sheet joining portions 91 provided per unit area in region X (area ratio), thereby making it difficult for the skin-side sheets 22 and 23 to expand or contract in the left-right direction in region Y. With such a configuration, the degree of design freedom regarding the range in which the stretchability acts and the strength of the stretchability can be increased by adjusting the density and size of the formed expansion / contraction reducing portions 92.

[0065] Furthermore, the outer casing member 20 may have a portion of the non-skin-facing sheet 21 folded downward at its upper end in the vertical direction. In Figure 3, the non-skin-facing sheet 21 has a folded portion 21ff, which is a portion folded downward in the vertical direction (rear side in the vertical direction) and towards the skin in the thickness direction at the front folding position FL20f. The folded portion 21ff is joined to an adjacent sheet member (skin-facing sheet 22 in Figure 3) in the thickness direction by an adhesive such as a hot melt adhesive, at least in part. In addition, a waist elastic member 25f oriented in the lateral direction (left-right direction) may be provided between the folded portion 21ff and the adjacent sheet member (skin-facing sheet 22) in the thickness direction. The waist elastic member 25f can be made of, for example, elastic thread, and is fixed to the outer casing member 20 in a state that is stretched in the lateral direction. When the waist elastic member 25f contracts laterally, the fit of the waist opening 1a (described later) in the front waist portion FA of the sanitary shorts 1 is improved.

[0066] Similarly, in Figure 3, the non-skin-facing sheet 21 has a folded portion 21bf, which is folded back at the rear folding position FL20b on the lower side (front side in the vertical direction) and on the skin side in the thickness direction. In addition, a waist elastic member 25b may be provided between the folded portion 21bf and the adjacent sheet member (skin-facing sheet 23) in the thickness direction, oriented in the lateral direction (left-right direction). The waist elastic member 25b improves the fit of the waist opening 1a (described later) in the rear waist portion BA of the sanitary shorts 1. However, the folded portions 21ff and 21bf are not necessarily required.

[0067] From the unfolded state shown in Figure 2, the sanitary shorts 1 are folded in half lengthwise, with the absorbent body 10 and outer material 20 being folded at the central position CL in the longitudinal direction (shown as a dashed line in Figure 2). In this folded state, the lateral sides 20fe of the front waist portion FA and the lateral sides 20be of the rear waist portion BA of the outer material 20, which overlap in the front-to-back direction, are joined using known joining means such as seal welding, forming a pair of side joints 60, 60. As a result, the folded outer material 20 is connected in a ring shape on the front (abdominal side) and rear (dorsal side), forming a waist opening 1a and a pair of leg openings 1b as shown in Figure 1, resulting in panty-type sanitary shorts 1.

[0068] <Manufacturing method for sanitary shorts 1> Next, we will explain how to manufacture the menstrual panties 1. First, we will explain the overall flow of the manufacturing process for the menstrual panties 1. Figure 5 is a flowchart showing the manufacturing process for the menstrual panties 1. Figure 6 is a conceptual diagram explaining the flow when the menstrual panties 1 are manufactured. Note that in Figures 5 and 6, some parts of the manufacturing process have been omitted in order to simplify the explanation. For example, the process of folding the outer material 20 vertically at the front and rear ends FL20f and FL20b to form the folded parts 21ff and 21bf (see Figure 3) has been omitted. Also, the absorbent body 10 is assumed to be supplied in a completed state, and the explanation of the manufacturing process for the absorbent body 10 has been omitted.

[0069] The sanitary shorts 1 are manufactured continuously by sequentially carrying out each process (S101 to S107) shown in Figure 5. First, a conveying process is carried out to convey each material constituting the sanitary shorts 1 in the conveying direction (hereinafter also referred to as the "MD direction") (conveying process S101). The conveying direction (MD direction) is the direction along the left-right direction of the sanitary shorts 1 in the unfolded state shown in Figures 2 and 4. In this embodiment, a continuous non-skin sheet 21a, in which the non-skin sheet 21 is connected in the left-right direction (MD direction), is unwound from the raw material roll and then conveyed from the upstream side to the downstream side in the MD direction at a predetermined conveying speed by a conveying mechanism (conveying rollers, etc.) not shown. Similarly, continuous skin-side sheets 22a (23a), in which the skin-side sheets 22 (23) are connected in the left-right direction (MD direction), are each unwound from the raw material roll and then transported from the upstream side to the downstream side in the MD direction at a predetermined transport speed by a transport mechanism (transport rollers, etc.) not shown. The continuous skin-side sheets 22a and 23a may be supplied by dividing a single material into two materials by cutting it with a slitter or the like, or they may be supplied as different materials.

[0070] Next, an exterior member forming process is performed (exterior member forming process S102) in which the exterior member 20 is connected in the MD direction by the non-skin side sheet continuum 21a and skin side sheet continuum 22a, 23a that are conveyed in the MD direction to form an exterior member continuum (stretchable composite sheet). As will be described in detail later, in the exterior member forming process S102, at least a process to join the non-skin side sheet continuum 21a and the skin side sheet continuum 22a, 23a is performed (S203), and a process to form a stretch reduction region LE is performed (S204).

[0071] Next, an absorbent body attachment process is performed (absorbent body attachment process S103), in which the absorbent body 10 is attached to the continuous body of the exterior member 20 (stretchable composite sheet). As described above, the absorbent body 10 is supplied in a completed state and is attached using a transfer mechanism (e.g., a transfer drum) not shown, such that the longitudinal direction (vertical direction in Figure 2) of the absorbent body 10 is aligned with the intersecting direction (hereinafter also called the "CD direction") perpendicular to the transport direction (MD direction). In this embodiment, the absorbent body 10 is attached to the portion of the exterior member 20 (continuous body) that overlaps with the stretch reduction region LE using an adhesive such as a hot melt adhesive.

[0072] Next, a leg opening forming process is performed on the exterior member 20 (continuous body) onto which the absorbent body 10 has been transferred, to form the leg opening 1b (leg opening forming process S104). The leg opening 1b is formed by cutting a predetermined area of ​​the exterior member 20 (continuous body) (for example, the area enclosed by the dashed line in Figure 4) using a cutting mechanism (not shown).

[0073] Next, the absorbent body 10 and the outer casing member 20 (continuous) are folded in half at a predetermined position in the CD direction (folding process S105). In the folding process S105, the absorbent body 10 and the outer casing member 20 (continuous) are folded in half in the CD direction with a fold line at a position corresponding to the central position CL in the vertical direction of Figure 2, by a folding mechanism (not shown), so that the folded outer casing members 20 are superimposed in the thickness direction.

[0074] Next, a joining process is performed to join the outer covering members 20 (continuous bodies) that are overlapped in the thickness direction at positions corresponding to the lateral sides 20fe and 20be of each sanitary shorts 1 (joining process S106). In joining process S106, a sealing joint is performed along the CD direction by a joining mechanism (not shown), and a side joint portion 60 along the CD direction is formed. As a result, multiple panty-shaped sanitary shorts 1 are made up in a continuous state along the MD direction (see Figure 6).

[0075] Next, a cutting process is performed to cut the continuous mass of panty-type sanitary shorts 1 being transported in the MD direction into individual panty-type sanitary shorts 1,1... (cutting process S107). In cutting process S107, a cutting mechanism (not shown) cuts the continuous mass of panty-type sanitary shorts 1 that is continuous in the MD direction at predetermined positions in the MD direction (both ends of the sanitary shorts 1 in the lateral direction). This produces individual panty-type sanitary shorts 1.

[0076] The manufactured panty-type sanitary shorts 1 are further folded downstream in the MD direction, packed individually or in groups using packaging material, packaged, and then shipped and distributed to the market as products.

[0077] Figure 7 is a flowchart of each process performed in the exterior member formation process S102. Figure 8 is a diagram illustrating the configuration of the manufacturing apparatus 200 for forming the exterior member 20 (stretchable composite sheet). The manufacturing apparatus 200 shown in Figure 8 constitutes a part of the entire manufacturing line for the sanitary shorts 1 (see Figure 6) and includes a heating mechanism 210, a stretching mechanism 220, a sheet joining mechanism 230, and a stretch reduction mechanism 240.

[0078] In the exterior member formation process S102, first, a heat treatment S201 and a stretching treatment S202 are performed on the skin-side sheet continuum 22a (23a), which is not yet elastic, in order to impart elasticity to it. However, if the skin-side sheet continuum 22a (23a) is supplied to the manufacturing apparatus 200 as a sheet member (stretchable nonwoven fabric) that already possesses elasticity, the heat treatment S201 and the stretching treatment S202 do not need to be performed in the exterior member formation process S102.

[0079] In the heat treatment S201, the skin-side sheet continuum 22a and skin-side sheet continuum 23a are heated while being conveyed in the MD direction, thereby preventing the stretchable fibers from being cut or the nonwoven fabric itself from tearing in the next stretching process S202. In Figure 8, the skin-side sheet continuum 22a (23a) is heated by passing it through a heating mechanism 210 equipped with multiple heated conveying rollers 211. The heated conveying rollers 211 are conveying rollers that can freely control the temperature of their outer surfaces, and the heating conditions (heating temperature, heating time, etc.) are appropriately adjusted according to the type of fibers constituting the nonwoven fabric and their melting points.

[0080] Next, a stretching treatment S202 is performed on the skin-side sheet continuum 22a (23a) to give it elasticity along the MD direction (lateral direction). The stretching treatment is carried out using a stretching mechanism 220 equipped with a pair of gear rolls 221 and 222. Figure 9 is a diagram illustrating the stretching treatment using the stretching mechanism 220.

[0081] The gear rolls 221 and 222 are a pair of upper and lower roll mechanisms that rotate around a rotation axis along the CD direction with their outer circumferential surfaces facing each other. The outer circumferential surface of the gear roll 221 has multiple peaks 221m (corresponding to gear teeth) and valleys 221v alternately formed along the direction of rotation, and each peak 221m and each valley 221v extends in the CD direction. The outer circumferential surface of the gear roll 222 also has similar alternating peaks 222m (gear teeth) and valleys 222v formed thereon. When the gear rolls 221 and 222 are rotating, the peaks 221m and valleys 222v of one gear roll 221 engage with the valleys 222v of the other gear roll 222, so that the peaks 221m of one gear roll 221 fit into the valleys 222v of the other gear roll 222, and the peaks 221m and valleys 222v mesh with each other with a small gap between them. During this rotation, the skin-side sheet continuum 22a (23a) passes between the pair of gear rolls 221 and 222 in an extended state along the MD direction.

[0082] As the skin-side sheet continuum 22a(23a) passes between a pair of gear rolls 221 and 222, it is deformed in a three-point bending manner by the adjacent peaks 222m, 222m of one gear roll 222 and the peak 221m of the other gear roll 221 that enters the valley 222v between them (see Figure 9). At this time, the portion of the skin-side sheet continuum 22a(23a) that is in contact with the top surface of the peaks 221m(222m) of the gear rolls 221(222) is difficult to stretch because it is in contact with the top surface in a manner that is generally immobile relative to the top surface. On the other hand, the portion between the portion in contact with the top surface is stretched based on the intrusion of the peaks 221m(222m). As a result, the skin-side sheet continuum 22a(23a) is processed so that the stretched portion and the portion that is difficult to stretch are arranged alternately in the MD direction. Then, in the stretched portion, the stretchable fibers of the nonwoven fabric constituting the skin-side sheet continuum 22a (23a) are partially stretched. In other words, by passing between the pair of gear rolls 221 and 222, at least some of the stretchable fibers in the skin-side sheet continuum 22a (23a) are stretched. As a result, the skin-side sheet continuum 22a (23a) exhibits elasticity along the MD direction based on the elastic deformation of the stretchable fibers.

[0083] The stretched skin-side sheet continuum 22a (23a) is transported in the MD direction in its stretched state, merges with the non-skin-side sheet continuum 21a and is laminated, after which a sheet joining process S203 is performed in the sheet joining mechanism 230 in which the skin-side sheet continuum 22a (23a) and the non-skin-side sheet continuum 21a are joined to each other. Figures 10A and 10B illustrate the sheet joining mechanism 230.

[0084] The sheet joining mechanism 230 includes a pattern roll 231 and an ultrasonic horn 235, and joins the skin-side sheet continuum 22a (23a) and the skin-side sheet continuum 21a by so-called ultrasonic welding. The pattern roll 231 is a cylindrical rotating body that can rotate around a rotation axis along the CD direction, and a plurality of joining patterns 231p for forming the sheet joining portion 91 (see Figure 4) are provided on its outer circumferential surface so as to protrude radially outward. In this embodiment, the joining patterns 231p are arranged on the outer circumferential surface of the pattern roll 231 in the area indicated by the shaded area in Figure 10A. It is preferable that the joining patterns 231p are provided in an area with a width wider than the non-skin-side sheet continuum 21a and the skin-side sheet continuum 22a (23a) in the CD direction.

[0085] The ultrasonic horn 235 is positioned opposite the outer surface of the pattern roll 231 and generates ultrasonic vibrations from its tip toward the pattern roll 231. In Figure 10A, four ultrasonic horns 235a to 235d are arranged in a row along the CD direction, and by generating ultrasonic vibrations from each of the ultrasonic horns 235a to 235d, ultrasonic welding can be performed in any region along the CD direction.

[0086] In this embodiment, as shown in Figure 10B, a non-stretchable sheet member (nonwoven fabric), the non-skin-side sheet continuum 21a, is wound around the pattern roll 231. Then, a stretchable skin-side sheet continuum 22a (23a) is supplied on top of the non-skin-side sheet continuum 21a (outside the radial direction of the pattern roll 231) and laminated. The laminated non-skin-side sheet continuum 21a and skin-side sheet continuum 22a (23a) are sandwiched between the pattern roll 231 and the ultrasonic horn 235, and the pattern roll 231 rotates while ultrasonic vibrations are applied from the ultrasonic horn 235. As a result, a plurality of sheet joints 91 (see Figure 4) are formed based on the joining pattern 231p provided on the outer circumferential surface of the pattern roll 231, and the non-skin-side sheet continuum 21a and the skin-side sheet continuum 22a (23a) are joined to form a continuous exterior member 20. The continuous body of the exterior member 20 formed by the sheet joining process S203 is a continuous body of composite stretchable sheets, which consists of multiple sheets laminated together, including a stretchable sheet that has elasticity in the MD direction.

[0087] In Figure 10, an example was shown in which the sheet joining mechanism 230 joins the non-skin side sheet continuum 21a and the skin side sheet continuum 22a (23a) using ultrasonic welding means. However, other joining means may also be used to join the non-skin side sheet continuum 21a and the skin side sheet continuum 22a (23a). For example, known heat welding (heat sealing) means may be used for joining.

[0088] Next, a stretch reduction process S204 is performed to form a stretch reduction region to reduce the stretchability in a predetermined area of ​​the skin-side sheet continuum 22a (23a). The stretch reduction region is formed at a predetermined pitch in the MD direction using a stretch reduction mechanism 240 on the skin-side sheet continuum 22a (23a) and the non-skin-side sheet continuum 21a that are conveyed in the MD direction. Figures 11A and 11B illustrate the stretch reduction mechanism 240.

[0089] The expansion / contraction reduction mechanism 240 is positioned downstream of the sheet joining mechanism 230 in the MD direction and includes a pattern roll 241 and an ultrasonic horn 245 (see Figure 8). Then, by ultrasonic welding, expansion / contraction reduction sections 92 (see Figure 4) are formed in predetermined areas of the skin-side sheet continuum 22a (23a) and the non-skin-side sheet continuum 21a.

[0090] The pattern roll 241 is a cylindrical rotating body that can rotate around a rotation axis along the CD direction, and a pattern plate 242 is provided on the outer circumferential surface of the rotating body in a portion of the circumferential region. The pattern plate 242 is a member provided with multiple joining patterns 242p for forming the expansion / contraction reduction section 92 (see Figure 4) that protrude radially outward, and as shown in Figure 11A, a pair of pattern plates 242 are provided on one side and the other side of the central position CL in the CD direction. The ultrasonic horn 245 is positioned opposite the outer circumferential surface of the pattern roll 241 and generates ultrasonic vibrations from its tip toward the pattern roll 241 (pattern plate 242). In the expansion / contraction reduction mechanism 240 of this embodiment, the ultrasonic horn 245 is provided so as to face the outer circumferential surface of the pattern roll 241 from the vertically above side, sandwiching the skin-side sheet continuum 22a (23a) and the non-skin-side sheet continuum 21a.

[0091] Then, with the laminated non-skin-side sheet continuum 21a and skin-side sheet continuum 22a (23a) sandwiched between the pattern roll 241 and the ultrasonic horn 245, the pattern roll 241 rotates while ultrasonic vibrations are applied from the ultrasonic horn 245. When the pattern roll 241 faces the portion of its outer surface that has the pattern plate 242, ultrasonic welding is performed, and a stretch reduction portion 92 (stretch reduction area LE) is formed based on the joining pattern 242p. In the portion of the pattern roll 241's outer surface that does not have the pattern plate 242, ultrasonic welding is not performed, and the stretch reduction portion 92 (stretch reduction area LE) is not formed.

[0092] In this embodiment, the stretch reduction portion 92 (stretch reduction region LE) is formed in the stretch reduction process S204 so as to overlap with a part of the area where the sheet joint portion 91 is formed. As a result, the stretchability of the skin-side sheet continuum 22a (23a) is reduced in that part of the area (stretch reduction region LE). Furthermore, in this embodiment, as shown in Figure 11B, in the stretch reduction process S204, the stretch reduction portion 92 is formed while the skin-side sheet continuum 22a (23a) and the non-skin-side sheet continuum 21a are conveyed along the tangential direction of the pattern roll 241 without wrapping around the outer surface of the pattern roll 241.

[0093] Through the above process, a continuous body of exterior member 20 (stretchable composite sheet) is formed, in which expansion / contraction reduction regions LE are provided at a predetermined pitch (interval) in the MD direction.

[0094] <Regarding the manufacturing of menstrual panties in different sizes> Menstrual panties 1 are manufactured in multiple sizes to suit the user's body shape. For example, when manufacturing menstrual panties 1 in three sizes: S, M, and L, it is necessary to change the length of the outer material 20 in the MD direction and CD direction (dimensions in the stretched state) for each different size. With the manufacturing apparatus 200 of this embodiment, it is possible to manufacture multiple types of menstrual panties 1 of different sizes without changing the equipment. The following describes how to manufacture menstrual panties 1 of different sizes using the manufacturing apparatus 200.

[0095] Figure 12 illustrates the manufacturing of sanitary shorts 1 in different sizes. Figure 12 shows the case of manufacturing three types of sanitary shorts 1 in sizes S, M, and L. When manufacturing sanitary shorts 1 in different sizes, it is necessary to change the pitch (the lateral length of the sanitary shorts 1 in the unfolded and extended state) of the continuous body of outer material 20 (composite stretchable sheet) that is conveyed in the MD direction. In Figure 12, when manufacturing S-sized sanitary shorts 1, the pitch of the continuous body of outer material 20 arranged in the MD direction is defined as Pa (first pitch). This pitch Pa corresponds to the lateral length W20 (see Figure 2) of the outer material 20 in the extended state. Then, in the cutting process S105 described in Figure 5, by cutting the continuous body of outer material 20 at each pitch Pa (first pitch), S-sized (first pitch width) sanitary shorts can be manufactured.

[0096] Similarly, when manufacturing L-sized sanitary shorts 1, which are larger than S-sized, the pitch of the continuous outer material 20 arranged in the MD direction is set to Pc (second pitch). Also, when manufacturing M-sized sanitary shorts 1, which are an intermediate size between S-sized and L-sized, the pitch of the continuous outer material 20 arranged in the MD direction is set to Pb (third pitch) (Pa <Pb<Pc)。

[0097] On the other hand, the absorbent body 10 is generally of a common size for menstrual panties 1 of different sizes (S, M, L). Therefore, it is preferable that the stretch-reducing region LE of the outer casing member 20, to which the absorbent body 10 is attached, is also formed to be the same size for menstrual panties 1 of different sizes (S, M, L). In other words, it is preferable that the length Wle of the stretch-reducing region LE in the MD direction is approximately the same regardless of the size of the menstrual panties 1.

[0098] In this case, the ratio of the length (pitch) of the outer material 20 to the length of the stretch reduction area LE differs for each size of the sanitary shorts 1 in the MD direction. In Figure 12, the relationship is (Wle / Pa) > (Wle / Pb) > (Wle / Pc). Conventionally, when manufacturing products with different ratios of length (pitch) of the outer material 20 to the length of the stretch reduction area LE, it was necessary to adjust the manufacturing process of the stretch reduction area LE. For example, in a device corresponding to the stretch reduction mechanism 240 explained in Figure 11, multiple types of pattern rolls 241 are prepared, each with an adjusted range in which the joining pattern 242p (pattern plate 242) is placed for each size. When manufacturing products of different sizes, products of different sizes were manufactured by exchanging these multiple types of pattern rolls 241, in other words, by changing the setup. As a result, the time and cost required for setup changes were large, making efficient manufacturing difficult.

[0099] In contrast, in this embodiment, menstrual panties 1 of different sizes can be manufactured using a common manufacturing apparatus 200 (stretch reduction mechanism 240) without changing the setup or other procedures.

[0100] For example, when manufacturing a size M sanitary shorts 1 with the manufacturing apparatus 200, a continuous body of outer material 20 arranged in the MD direction at a pitch Pb (third pitch) is transported at a predetermined transport speed V, while the expansion / contraction reduction mechanism 240 forms expansion / contraction reduction regions LE at each pitch Pb. At this time, the angular velocity Vb of the pattern roll 241 is set so that the rotation speed of the pattern roll 241 of the expansion / contraction reduction mechanism 240 is equal to the transport speed V of the outer material 20, and the pattern roll 241 is rotated at a constant angular velocity Vb. In addition, the radius R241 of the pattern roll 241 is adjusted so that the pattern roll 241 rotates exactly once while the continuous body of outer material 20 is transported by a pitch Pb (third pitch) in the MD direction. In other words, the pattern roll 241 is adjusted so that 2 × π × R241 = Pb. With this configuration, while the pattern roll 241 rotates once at a constant speed Vb, the continuous body of the exterior member 20 is conveyed by a pitch Pb (third pitch), and the expansion / contraction reduction region LE is formed by the pattern plate 242 provided on the outer surface of the pattern roll 241. Therefore, as shown in Figure 12, the expansion / contraction reduction region LE can be accurately formed for each pitch Pb (third pitch).

[0101] Next, when manufacturing the sanitary shorts 1 of size S using the same manufacturing apparatus 200, while the continuum of the exterior members 20 arranged at a pitch Pa (first pitch) in the MD direction is being conveyed at a conveyance speed V' (V' < V) in the MD direction, the stretch reduction mechanism 240 forms a stretch reduction region LE for each pitch Pa. At this time, the speed (angular velocity) Va at which the pattern roll 241 rotates is the same magnitude as the angular velocity Vb when manufacturing the sanitary shorts 1 of size M (Va = Vb), and the pattern roll 241 rotates at a constant angular velocity Va. Then, similar to the case of manufacturing the sanitary shorts 1 of size M, while the pattern roll 241 makes one rotation, the continuum of the exterior members 20 is conveyed by a pitch Pa (first pitch), and at the same time, the stretch reduction region LE is formed. Since the pattern roll 241 rotates at the same speed as in the case of size M, the length of the section sandwiched between the pattern plate 242 of the pattern roll 241 and the ultrasonic horn 245 while the exterior member 20 is being conveyed by a pitch Pa (first pitch) in the MD direction is also the same for both size M and size S. In other words, the range in which the stretch reduction region LE is formed by applying ultrasonic vibration from the ultrasonic horn 245 to the exterior member 20 is equal for both size M and size S. That is, the width Wle of the stretch reduction region LE in size M and the width Wle of the stretch reduction region LE in size S are formed to have the same length (see FIG. 12).

[0102] On the one hand, the conveying speed V' of the exterior member 20 in the MD direction of the S size is smaller than the conveying speed V of the exterior member 20 in the MD direction of the M size (V' < V), while the speed (angular velocity) Va at which the pattern roll 241 rotates when manufacturing the S size is the same as the speed (angular velocity) Vb at which the pattern roll 241 rotates when manufacturing the M size (Va = Vb). That is, since the conveying speed V' of the exterior member 20 is slower than the speed (angular velocity) Va at which the pattern roll 241 rotates, a deviation occurs between the two speeds. In this case, the conveyance of the exterior member 20 becomes unstable, and there is a possibility that the stretch reduction region LE is difficult to be accurately formed. However, in the present embodiment, the exterior member 20 has elasticity in the MD direction and can be extended or contracted along the MD direction in response to the rotation of the pattern roll 241. Therefore, the above problems are unlikely to occur.

[0103] FIGS. 13A and 13B are diagrams for explaining the behavior when the conveying speed of the exterior member 20 and the speed (angular velocity) at which the pattern roll 241 rotates are different in the stretch reduction process S204. In FIGS. 13A and 13B, when manufacturing the exterior member 20 of the S size (the non-skin side sheet 21 and the skin side sheet 22 (23)), the case where the conveying speed V' of the exterior member 20 is slower than the speed (angular velocity) Va at which the pattern roll 241 rotates is shown.

[0104] <C Figure 13A shows the behavior of the exterior member 20 when it is sandwiched between the pattern plate 242 and the ultrasonic horn 245 of the pattern roll 241. In this case, based on the speed difference between the transport speed V' and the angular velocity Va, a force (tension) Tb acts on the exterior member 20, pulling it downstream in the MD direction from the portion sandwiched between the pattern roll 241 (pattern plate 242) and the ultrasonic horn 245. In other words, in the MD direction, the elongation rate per unit length of the exterior member 20 downstream of the pattern roll 241 and ultrasonic horn 245 is greater than the elongation rate per unit length of the exterior member 20 upstream of the pattern roll 241 and ultrasonic horn 245. Then, by performing the expansion / contraction reduction process while tension Tb is applied downstream in the transport direction to the expandable exterior member 20, it is possible to form an expansion / contraction reduction region LE equivalent to that of an M-sized exterior member 20, even if the transport speed V' of the exterior member 20 in the MD direction is slower compared to when manufacturing an M-sized exterior member 20.

[0105] Figure 13B shows the behavior when the exterior member 20 is separated from the pattern plate 242 of the pattern roll 241. In the portion of the exterior member 20 that is not sandwiched between the pattern plate 242 and the ultrasonic horn 245, the tension Tb shown in Figure 13A no longer acts, so the transport motion of the exterior member 20 in the MD direction and the rotation motion of the pattern roll 241 no longer interfere with each other. That is, the expansion and contraction of the exterior member 20 due to the effect of tension Tb is released, the exterior member 20 is transported in the MD direction at transport speed V', and the pattern roll 241 rotates at angular velocity Va. This operation makes it possible to form expansion and contraction reduction regions LE for each pitch Pa (first pitch) without replacing the pattern roll 241.

[0106] Next, when manufacturing the L-sized sanitary shorts 1 using the same manufacturing apparatus 200, while the continuum of the exterior members 20 arranged at a pitch Pc (second pitch) in the MD direction is being conveyed at a conveyance speed V″ (V < V″) in the MD direction, the stretch reduction mechanism 240 forms a stretch reduction region LE for each pitch Pc. At this time, the rotational speed (angular velocity) Vc of the pattern roll 241 is the same magnitude as the angular velocity Vb when manufacturing the M-sized sanitary shorts 1, and the pattern roll 241 rotates at a constant angular velocity Vc. And, similar to the case of manufacturing the M-sized and S-sized sanitary shorts 1, while the continuum of the exterior members 20 is conveyed by the pitch Pc (second pitch) during one rotation of the pattern roll 241, the stretch reduction region LE is formed. Since the pattern roll 241 rotates at the same speed as in the case of the M size, the length of the section sandwiched between the pattern roll 241 (pattern plate 242) and the ultrasonic horn 245 while the exterior member 20 is conveyed by the pitch Pc (second pitch) in the MD direction is also the same for the M size and the L size. In other words, the range in which the stretch reduction region LE is formed by applying ultrasonic vibration from the ultrasonic horn 245 to the exterior member 20 is equal for the M size and the L size. That is, the width Wle of the stretch reduction region LE in the M size and the width Wle of the stretch reduction region LE in the L size are formed to be the same length (see FIG. 12).

[0107] On the other hand, while the conveyance speed V″ of the L-sized exterior member 20 in the MD direction is greater than the conveyance speed V of the M-sized exterior member 20 in the MD direction (V < V″), the rotational speed (angular velocity) Vc of the pattern roll 241 when manufacturing the L size is the same speed as the rotational speed (angular velocity) Vb of the pattern roll 241 when manufacturing the M size. That is, since the conveyance speed V″ of the exterior member 20 is faster than the rotational speed (angular velocity) Vc of the pattern roll 241, a deviation occurs between the two speeds, and there is a possibility that it becomes difficult to accurately form the stretch reduction region LE. However, in the present embodiment, since the exterior member 20 has elasticity in the MD direction and can be stretched or contracted along the MD direction in response to the rotation of the pattern roll 241, the above problems are unlikely to occur.

[0108] Figures 14A and 14B illustrate the behavior in the expansion / contraction reduction process S204 when the transport speed of the exterior member 20 and the rotation speed (angular velocity) of the pattern roll 241 are different. Figures 14A and 14B show the case when manufacturing an L-sized exterior member 20 (non-skin side sheet 21 and skin side sheet 22 (23)), where the transport speed V'' of the exterior member 20 is faster than the rotation speed (angular velocity) Vc of the pattern roll 241.

[0109] Figure 14A shows the behavior of the exterior member 20 when it is sandwiched between the pattern plate 242 and the ultrasonic horn 245 of the pattern roll 241. In this case, based on the speed difference between the transport speed V'' and the angular velocity Vc, a force (tension) Tt acts on the exterior member 20, pulling it upstream in the MD direction from the portion sandwiched between the pattern roll 241 (pattern plate 242) and the ultrasonic horn 245. In other words, in the MD direction, the elongation rate per unit length of the exterior member 20 upstream of the pattern roll 241 and ultrasonic horn 245 is greater than the elongation rate per unit length of the exterior member 20 downstream of the pattern roll 241 and ultrasonic horn 245. Then, by performing the expansion / contraction reduction process while tension Tt is applied upstream in the transport direction to the expandable exterior member 20, it is possible to form an expansion / contraction reduction region LE equivalent to that of an M-sized exterior member 20, even if the transport speed V'' of the exterior member 20 in the MD direction is faster than when manufacturing an M-sized exterior member 20.

[0110] Figure 14B shows the behavior when the exterior member 20 is separated from the pattern plate 242 of the pattern roll 241. In the portion of the exterior member 20 that is not sandwiched between the pattern plate 242 and the ultrasonic horn 245, the tension Tt shown in Figure 14A no longer acts, so the transport operation of the exterior member 20 in the MD direction and the rotation operation of the pattern roll 241 no longer interfere with each other. That is, with the expansion and contraction of the exterior member 20 due to tension Tt released, the exterior member 20 is transported in the MD direction at transport speed V'', and the pattern roll 241 rotates at angular velocity Vc. This operation makes it possible to form an expansion / contraction reduction region LE at each Pc (second pitch) without replacing the pattern roll 241.

[0111] Thus, in this embodiment, the rotation speed (angular velocity) of the pattern roll 241 is set such that the pattern roll 241 completes one rotation and forms a stretch reduction region LE while the continuous body of the outer material 20 (stretchable composite sheet) is conveyed by a pitch equivalent to one piece of each size. Therefore, it is possible to manufacture sanitary shorts 1 of multiple sizes (pitches) using the same pattern roll 241. In other words, outer material 20 (stretchable composite sheet) of different lengths according to the size of the absorbent article can be efficiently manufactured without changing the setup of the manufacturing equipment.

[0112] Furthermore, in this embodiment, the outer material 20 (stretchable composite sheet) is constructed by laminating and joining together a skin-side sheet continuous 22a (23a) which is a stretchable nonwoven fabric and a non-skin-side sheet 21 which is a non-stretchable nonwoven fabric. Because nonwoven fabric is used for both the stretchable and non-stretchable sheets, the breathability is higher compared to cases where resin films or the like are used, and a good feel against the skin is easily achieved. In addition, because it is highly flexible and tear-resistant, it is suitable for use as wearable items such as absorbent articles. Furthermore, by forming the stretch reduction section described above, it is easy to adjust the stretchability locally. Thus, in this embodiment, it is possible to manufacture a composite stretchable sheet with stretchability while achieving a balance of breathability, flexibility, feel against the skin, and strength with a minimal configuration.

[0113] Furthermore, the stretchable nonwoven fabric, used as an elastic sheet, is obtained by subjecting the woven fabric to a stretching process (stretching treatment S201) to impart elasticity before joining it with a non-stretchable sheet. Therefore, it is unnecessary to prepare by procuring the stretchable nonwoven fabric as a base sheet in advance. In addition, since the base sheet can be treated as a non-stretchable sheet until the stretching treatment is performed, handling is easy when manufacturing the composite stretchable sheet, such as winding it into a roll to form a base roll. Moreover, by using the stretching mechanism 220 provided in the manufacturing apparatus 200, elasticity can be stably imparted even to nonwoven fabrics that do not exhibit elasticity (non-stretchable nonwoven fabrics).

[0114] Furthermore, in the sanitary shorts 1 of this embodiment, when the outer material 20 is viewed in the thickness direction, a stretch reduction region LE is formed in the portion that overlaps with the sheet joining portion 91 that joins the skin-side sheet 22 (23) and the non-skin-side sheet 21. That is, the stretchable skin-side sheet 22 (23) and the non-stretchable non-skin-side sheet 21 are laminated in the thickness direction and joined to each other via a plurality of sheet joining portions 91, thereby providing stretchability throughout the entire laminated structure of the two sheets. Then, by providing a stretch reduction region LE in a portion of the stretchable area (the portion that overlaps with the absorbent body 10), the stretchability is partially reduced. In this way, by providing stretchability in the portion where the two sheets are joined, while reducing the stretchability in a portion of that area, it becomes easier to efficiently manufacture sanitary shorts 1 (outer material 20) of different sizes. For example, even if the length of the exterior member 20 differs in the left-right direction (MD direction) and the size of the area exhibiting elasticity differs, the same elasticity reduction effect can be obtained even for different sizes by forming an elasticity reduction area LE overlapping a part of the area exhibiting elasticity. Therefore, exterior members 20 (stretchable composite sheets) of different sizes can be efficiently manufactured without changing the equipment or other modifications.

[0115] Furthermore, when manufacturing the exterior component 20 (stretchable composite sheet), the sheet bonding mechanism 230 can change the range in which the sheet bonding portion 91 is formed by changing the range of ultrasonic vibrations emitted by the ultrasonic horn 235 in the CD direction. Similarly, the stretch reduction mechanism 240 can change the range in which the stretch reduction portion 92 is formed by changing the range of ultrasonic vibrations emitted by the ultrasonic horn 245 in the CD direction. As a result, even if the size of the exterior component 20 differs not only in the MD direction (left-right direction of the sanitary shorts 1) but also in the CD direction (vertical direction of the sanitary shorts 1), the manufacturing equipment can be shared. Therefore, exterior component 20 (stretchable composite sheet) of different sizes in the vertical and left-right directions can be efficiently manufactured without changing the equipment.

[0116] Furthermore, the stretch reduction mechanism 240 seals and joins the stretchable skin-side sheet 22(23) and the non-stretchable non-skin-side sheet 21 by forming a stretch reduction section 92 using ultrasonic welding, thereby reducing the stretchability of the exterior member 20. Since the sheet members are sealed and joined using ultrasonic welding rather than heat welding, edge breakage due to heat is less likely to occur, and the stretch reduction region LE can be stably formed while suppressing the thermal impact on the stretchable skin-side sheet 22(23).

[0117] Similarly, the sheet joining mechanism 230 joins the stretchable skin-side sheet 22(23) and the non-stretchable non-skin-side sheet 21 by forming a sheet joining portion 91 using ultrasonic welding means. Specifically, in the sheet joining process S203 of this embodiment, as explained in Figure 8, sealing is performed with the sheets to be joined (skin-side sheet 22(23) and non-skin-side sheet 21) wrapped around the outer surface of the pattern roll 231. At this time, the non-stretchable non-skin-side sheet 21 is wrapped around the pattern roll 231, and then the stretchable skin-side sheet 22(23) is wrapped around the pattern roll 231 on top of the non-skin-side sheet 21. Then, while rotating the pattern roll 231, ultrasonic vibrations are applied by the ultrasonic horn 235 from the side facing the skin-side sheet 22(23) in the thickness direction, and the skin-side sheet 22(23) and the non-skin-side sheet 21 are joined. In other words, in the sheet joining process S203, ultrasonic welding is performed with the stretchable skin-side sheet 22(23) not in direct contact with the outer surface of the pattern roll 231.

[0118] In this embodiment, a stretchable nonwoven fabric is used as the stretchable skin-side sheet 22(23). However, if the stretchable nonwoven fabric were to be directly wrapped around the outer surface of the pattern roll 231, the stretchable fibers of the stretchable nonwoven fabric might get caught on the multiple bonding patterns 231p protruding from the surface of the pattern roll 231, potentially preventing stable conveyance. In contrast, by directly wrapping a non-stretchable non-skin-side sheet 21, which contains almost no stretchable fibers, around the outer surface of the pattern roll 231, and then wrapping the stretchable skin-side sheet 22(23) on top of the non-skin-side sheet 21, it becomes easier to suppress the stretchable fibers from getting caught on the pattern roll 231 (bonding patterns 231p). Therefore, the non-skin-side sheet 21 and the stretchable skin-side sheet 22(23) can be bonded together while stably conveying them.

[0119] Furthermore, although this embodiment has described the possibility of manufacturing multiple types of exterior members 20 (stretchable composite sheets) of different sizes, for example, when manufacturing exterior members 20 of S, M, and L sizes, it is preferable that the stretch reduction mechanism 240 be configured based on the intermediate size, M size. As described above, the pattern roll 241 of the stretch reduction mechanism 240 is configured such that the length of the outer surface in the circumferential direction (perimeter) is equal to the pitch Pb (third pitch) of one piece of the M-sized exterior member 20. With this configuration, the pattern roll 241 rotates once while the M-sized exterior member 20 is conveyed by the pitch Pb (third pitch), forming a stretch reduction region LE on the exterior member 20. In other words, a stretch reduction region LE can be formed for each pitch Pb (third pitch).

[0120] When manufacturing an exterior member 20 of size S, which is smaller than size M, the pattern roll 241 rotates once while the exterior member 20 is transported by pitch Pa (first pitch), forming an expansion / contraction reduction region LE on the exterior member 20. Similarly, when manufacturing an exterior member 20 of size L, which is larger than size M, the pattern roll 241 rotates once while the exterior member 20 is transported by pitch Pc (second pitch), forming an expansion / contraction reduction region LE on the exterior member 20. In other words, in this embodiment, regardless of the size of the exterior member 20 (composite expandable sheet), the pattern roll 241 rotates once while the product is transported by one pitch.

[0121] If the circumference of the pattern roll 241 were determined based on the L size, the difference between the pitch Pa (first pitch) of the S size exterior member 20 and the pitch Pc (second pitch) of the L size exterior member would become large, potentially leading to unstable operation. In contrast, in this embodiment, the circumference of the pattern roll 241 is determined based on the pitch Pb (third pitch) of the M size. Therefore, when manufacturing S size and L size exterior members 20, the difference between the pitch Pa (first pitch) and the pitch Pc (second pitch) is less likely to become excessively large, making it easier to accurately form the expansion / contraction reduction region LE according to each size with more stable operation.

[0122] Furthermore, as shown in Figures 13 and 14, in the expansion / contraction reduction process S204, the outer material 20 (non-skin side sheet 21 and skin side sheet 22(23)) is conveyed along the tangential direction of the pattern roll 241. That is, the outer material 20 is conveyed without being wrapped around the outer surface of the pattern roll 241. If the outer material 20 were to be conveyed while wrapped around the outer surface of the pattern roll 241, the frictional force generated between the outer material 20 and the outer surface of the pattern roll 241 would easily cause the outer material 20 to be strongly pulled upstream or downstream in the MD direction. In other words, the influence of fluctuations in the rotational speed (angular velocity) of the pattern roll 241 would become excessively large, and it may become difficult to maintain a constant range for the expansion / contraction reduction region LE. In contrast, in this embodiment, the outer material 20 (composite expansion / contraction sheet) is not wrapped around the outer surface of the pattern roll 241, and excessive pulling of the outer material 20 upstream or downstream in the conveying direction is suppressed. This makes it easier to stably form expansion / contraction reduction regions LE at predetermined pitches, even when the pattern roll 241 is rotated at a speed different from the transport speed of the exterior member 20.

[0123] Furthermore, in the MD direction, it is preferable that the length of the stretch reduction region LE be 1 / 2 or less of the pitch of the outer material 20 (the left-right length of one piece of the waist material). In other words, it is preferable that the stretch reduction region LE is formed such that the relative length of the stretch reduction region LE to the length of the outer material 20 is not excessively large. The longer the relative length of the stretch reduction region LE, the longer the range in which the pattern plate 242 is positioned in the circumferential direction of the pattern roll 241 when forming the stretch reduction region LE in the stretch reduction process S204. In this case, the section in which the outer material 20 is sandwiched between the pattern plate 242 and the ultrasonic horn 245 becomes longer during one rotation of the pattern roll 241 (while the outer material 20 is conveyed by one pitch) (see Figures 13A and 14A). Therefore, when manufacturing S-size or L-size sanitary shorts 1, the time during which the outer material 20 is pulled upstream or downstream in the MD direction becomes longer, which may make it difficult to stably form the stretch reduction region LE.

[0124] In contrast, if the length of the expansion / contraction reduction region LE is less than or equal to half the pitch of the exterior member 20 (composite stretchable sheet), the section in which the exterior member 20 is sandwiched between the pattern plate 242 and the ultrasonic horn 245 during one rotation of the pattern roll 241 will not become excessively long, and the exterior member 20 will not be easily pulled in the MD direction. As shown in Figure 12, in this embodiment, the length Wle of the expansion / contraction reduction region LE in the MD direction is less than or equal to half the pitch of the exterior member 20 in the MD direction (first pitch Pa, second pitch Pc, third pitch Pb). Therefore, in the expansion / contraction reduction process S204, the section in which the exterior member 20 is sandwiched between the pattern plate 242 and the ultrasonic horn 245 will not become excessively long, and the expansion / contraction reduction region LE can be stably formed even when the transport speed of the exterior member 20 and the rotation speed (angular velocity) of the pattern roll 241 are different.

[0125] As explained in Figure 11, when the expansion / contraction reduction mechanism 240 forms the expansion / contraction reduction region LE (expansion / contraction reduction section 92) using ultrasonic welding means, the exterior member 20 is intermittently sandwiched between the pattern roll 241 (pattern plate 242) and the ultrasonic horn 245. In other words, when the exterior member 20 is transported in the MD direction during the expansion / contraction reduction process S204, the exterior member 20 is transported in the MD direction without being continuously constrained in the thickness direction. For example, if the exterior member 20 were fixed (constrained) while being sandwiched in the thickness direction during the expansion / contraction reduction process S204, the transport operation may become unstable or the formation range of the expansion / contraction reduction region LE may be misaligned. In contrast, in this embodiment, since the exterior member 20 is not continuously constrained in the thickness direction, the transport operation and the formation operation of the expansion / contraction reduction region LE are more stable.

[0126] <Modified example of stretching reduction treatment S204> In the expansion / contraction reduction process S204, when forming an expansion / contraction reduction region LE (expansion / contraction reduction section 92) on the exterior member 20 (composite expansion / contraction sheet), the rotation speed (angular velocity) of the pattern roll 241 is set so that the pattern roll 241 rotates once while the exterior member 20 is transported by one pitch. In other words, in this embodiment, by appropriately setting the rotation speed of the pattern roll 241 according to the size (S, M, L) of the exterior member 20, the expansion / contraction reduction region LE can be formed at predetermined pitches without changing the pattern roll 241.

[0127] In the modified version, the pattern roll 241 is controlled to complete one rotation while the exterior member 20 is being transported by one pitch, with the rotation speed (angular velocity) of the pattern roll 241 varying according to the size of the product, thereby enabling the stable formation of the expansion / contraction reduction region LE. Figure 15 illustrates the rotation speed of the pattern roll 241 in the modified version of the expansion / contraction reduction process S204. Figure 15 shows the variation in angular velocity when T is the time it takes for the exterior member 20 to be transported by one pitch in the MD direction.

[0128] First, when manufacturing a standard M-sized sanitary shorts 1 (outer packaging 20), the pattern roll 241 is rotated at a constant angular velocity Vb, similar to the operation described in Figure 12, so that the pattern roll 241 completes one rotation while the outer packaging 20 is transported by one pitch (third pitch Pb). In Figure 15, the pattern roll 241 completes one rotation during the time T it takes for the outer packaging 20 to be transported by one pitch (third pitch Pb).

[0129] Next, when manufacturing the sanitary shorts 1 of size S (outer member 20), while the outer member 20 is sandwiched between the pattern plate 242 and the ultrasonic horn 245, the pattern roll 241 is rotated at an angular velocity Va slower than the angular velocity Vb in size M. The angular velocity Va of the pattern roll 241 is the same as the conveyance speed when the outer member 20 of size S is conveyed in the MD direction. That is, at the timing when the operation of forming at least the stretch reduction region LE is performed, the rotation speed of the pattern roll 241 is made to match the conveyance speed of the outer member 20. In FIG. 15, the pattern roll 241 rotates at an angular velocity Va (<Vb) in the section from time 0 to ta (the state of FIG. 13A). Then, in a part of the section where the outer member 20 is sandwiched between the part of the pattern roll 241 where the pattern plate 242 is not provided and the ultrasonic horn 245 (the state of FIG. 13B), the pattern roll 241 is rotated so that the angular velocity of the pattern roll 241 becomes faster than Va. That is, at the timing when the operation of forming the stretch reduction region LE is not performed (ultrasonic welding is not performed), the rotation speed of the pattern roll 241 is increased. In FIG. 15, in the section from time ta to T, the rotation of the pattern roll 241 is controlled such that the angular velocity of the pattern roll 241 is gradually increased and the angular velocity becomes Va at time T.

[0130] Similarly, when manufacturing L-sized sanitary shorts 1 (outer material 20), the pattern roll 241 is rotated at an angular velocity Vc that is faster than the angular velocity Vb in the M-sized shorts while the outer material 20 is sandwiched between the pattern plate 242 and the ultrasonic horn 245. The angular velocity Vc of the pattern roll 241 is the same as the transport speed when the L-sized outer material 20 is transported in the MD direction. In other words, at least at the timing when the operation to form the stretch reduction region LE is performed, the rotation speed of the pattern roll 241 and the transport speed of the outer material 20 are made to be the same. In Figure 15, the pattern roll 241 rotates at an angular velocity Vc (>Vb) in the section from time 0 to tc (state in Figure 14A). Then, in part of the section of the pattern roll 241 where the outer material 20 is sandwiched between the part where the pattern plate 242 is not provided and the ultrasonic horn 245 (state in Figure 14B), the pattern roll 241 is rotated so that its angular velocity is slower than Vc. In other words, at times when the operation to form the stretch reduction region LE is not performed (ultrasonic welding is not performed), the rotation speed of the pattern roll 241 is slowed down. In Figure 15, the rotation of the pattern roll 241 is controlled so that the angular velocity of the pattern roll 241 is gradually reduced in the interval from time tc to T, and the angular velocity of the pattern roll 241 becomes Vc at time T.

[0131] In this way, by adjusting the angular velocity of the pattern roll 241 so that the transport speed of the outer material 20 and the angular velocity of the pattern roll 241 are the same for each product size (pitch in the MD direction), the expansion reduction region LE can be formed more stably. At this time, when the expansion reduction region LE is not formed (the section in which the expansion reduction portion 92 is not formed), the speed of the pattern roll 241 is changed so that the pattern roll 241 rotates once while one pitch of outer material 20 is transported. In other words, the angular velocity of the pattern roll 241 is matched to the transport speed of the outer material 20 at the timing when the expansion reduction region LE is formed, and the pattern roll 241 is controlled to rotate once while one pitch of outer material 20 is transported. As a result, the expansion reduction region LE is accurately formed in the MD direction and is more likely to be formed at even intervals without variation. Therefore, outer material 20 (stretchable composite sheet) of different lengths can be manufactured with high precision according to the size of the sanitary shorts 1 to be manufactured.

[0132] ===Second Embodiment=== In the second embodiment, we will describe menstrual shorts 2, which differs from menstrual shorts 1 of the first embodiment in the configuration of the outer material 20. Since the basic configuration of menstrual shorts 2 other than the outer material 20 is substantially the same as that of menstrual shorts 1, we will omit the explanation of the configuration other than the outer material 20 below.

[0133] Figure 16 is a schematic cross-sectional view of the unfolded and stretched sanitary shorts 2 as seen from one side in the left-right direction, and corresponds to Figure 3 of the first embodiment. The outer material of the sanitary shorts 2 is a composite stretchable sheet with stretchability in the left-right direction, consisting of a non-skin side sheet 21, stretchable sheets 26, 27, and skin side sheets 28, 29 laminated in the thickness direction. The non-skin side sheet 21 is the same sheet material as the non-skin side sheet 21 in sanitary shorts 1 and is located on the non-skin side of the sanitary shorts 2.

[0134] The stretchable sheets 26 and 27 are stretchable sheet members laminated closer to the skin than the non-skin side sheet 21 on the front and back sides in the longitudinal direction, respectively, and in the sanitary shorts 2, they exhibit stretchability along the left-right direction. Examples of stretchable sheets 26 and 27 include stretchable resin films. However, the same stretchable nonwoven fabric as in the sanitary shorts 1 may be used for the stretchable sheets 26 and 27. The skin side sheets 28 and 29 are non-stretchable sheet members laminated closer to the skin than the stretchable sheets 26 and 27 on the front and back sides in the longitudinal direction, respectively, and the same nonwoven fabric as in the non-skin side sheet 21 can be used.

[0135] In the outer material 20 of the sanitary shorts 2, in the thickness direction, stretchable sheets 26 and 27 are sandwiched between the non-skin-side sheet 21 and the skin-side sheets 28 and 29, and the three layers of laminated sheet members are joined to each other by multiple sheet joining portions 91 scattered throughout the skin-side sheets 28 and 29. As a result, the portion of the outer material 20 in which the stretchable sheets 26 and 27 are provided is given elasticity in the left-right direction.

[0136] Figure 17 is a diagram illustrating the configuration of a manufacturing apparatus 200 for forming the outer material 20 of the sanitary shorts 2. The outer material 20 (stretchable composite sheet) of the sanitary shorts 2 can be manufactured in substantially the same manner as the outer material 20 described in the first embodiment. That is, by carrying out each step described in Figure 7, a continuous body of outer material 20 (stretchable composite sheet) that is continuous in the MD direction is manufactured. However, here, the explanation assumes that a stretchable resin film is used as the stretchable sheets 26 and 27. Specifically, since a stretchable nonwoven fabric like the skin-side sheets 22 and 23 in the sanitary shorts 1 is not used, the steps for imparting elasticity to the nonwoven fabric (heat treatment S201 and stretching treatment S202 in Figure 7) are not performed.

[0137] In the manufacturing process for the outer material of the sanitary shorts 2, the non-skin-side sheet continuum 21a, the skin-side sheet continuum 28a (29a), and the stretchable sheet continuum 26a (27a), which are all continuous in the MD direction, are joined to each other by the sheet joining mechanism 230 while stacked in the thickness direction (sheet joining process S203). The configuration of the sheet joining mechanism 230 in the second embodiment is substantially the same as that of the sheet joining mechanism 230 described in the first embodiment (see Figure 10).

[0138] In the second embodiment, as shown in Figure 17, a non-stretchable sheet member (nonwoven fabric), the non-skin-side sheet continuum 21a, is wound around the pattern roll 231, and a stretchable sheet continuum 26a (27a) is supplied stretched in the MD direction, overlapping the non-skin-side sheet continuum 21a. Furthermore, the skin-side sheet continuum 28a (29a) is supplied overlapping the stretchable sheet continuum 26a (27a). Then, with the three layers of sheet members sandwiched between the pattern roll 231 and the ultrasonic horn 235, the pattern roll 231 rotates while ultrasonic vibrations are applied from the ultrasonic horn 235. As a result, a plurality of sheet joints 91 are formed based on the joining pattern 231p provided on the outer surface of the pattern roll 231, and the three layers of sheet members (21a, 26a (27a), 28a (29a)) are joined to each other to form a continuous exterior member 20.

[0139] Next, a stretch reduction region is formed in a predetermined range in the MD direction of the stretchable sheet continuum 26a (27a) using the stretch reduction mechanism 240 (stretch reduction process S204). The configuration of the stretch reduction mechanism 240 in the second embodiment is substantially the same as that of the stretch reduction mechanism 240 described in the first embodiment (see Figure 11).

[0140] In the second embodiment as well, while one piece of the exterior member 20 (stretchable composite sheet) is conveyed in the MD direction, the pattern roll 241 rotates once, and the ultrasonic vibrations applied from the ultrasonic horn 245 form a stretch reduction region LE (stretch reduction section 92). As a result, a continuous body of the exterior member 20 (composite stretchable sheet) is manufactured in which the stretchability is reduced in the stretch reduction region LE.

[0141] In the second embodiment, the stretch reduction treatment S204 is performed by applying ultrasonic vibrations to the stretchable sheet continuous 26a (27a) made of a stretchable film or the like, which may form cuts or openings that penetrate the stretchable sheet (stretchable film) in the thickness direction. In this case, a hole is formed that penetrates the stretchable sheet 26 (27) in the thickness direction, and a stretch reduction section 92 is formed where the non-skin side sheet 21 and the skin side sheet 28 (29) are welded together in the thickness direction at the position where the through hole is formed (not shown). In such a stretch reduction section 92, the stretchability is reduced by forming an opening in the stretchable film, so that the exterior member 20 (composite stretchable sheet) as a whole is less prone to pulling or hardening, and the feel against the skin is improved when used as a wearable item such as sanitary shorts.

[0142] The exterior member 20 of the second embodiment is a composite stretchable sheet in which a non-stretchable sheet (nonwoven fabric) is bonded to both sides in the thickness direction of a stretchable sheet (stretchable film). Since the stretchable sheet is not exposed and both sides in the thickness direction are made of nonwoven fabric, it is possible to form a composite stretchable sheet with enhanced texture and strength. Furthermore, by changing the arrangement and configuration of the stretchable sheet, the stretchability characteristics (strength of stretchability and range of stretchability) can be easily adjusted, and a variety of composite stretchable sheets can be formed according to the application.

[0143] ===Other=== The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention may be modified and improved without departing from its spirit, and it goes without saying that equivalents thereof are included.

[0144] <Regarding the sheet joining mechanism 230 and the expansion / contraction reduction mechanism 240> In the above-described embodiment, the sheet joining mechanism 230 joined multiple stacked sheet members together by forming a sheet joining portion 91 by ultrasonic welding using a pattern roll 231 and an ultrasonic horn 235. In addition, the expansion / contraction reduction mechanism 240 formed an expansion / contraction reduction region LE by forming an expansion / contraction reduction portion 92 by ultrasonic waves using a pattern roll 241 and an ultrasonic horn 245. However, the sheet joining portion 91 and the expansion / contraction reduction portion 92 may be formed using welding means other than ultrasonic welding. For example, the sheet joining portion 91 and the expansion / contraction reduction portion 92 may be formed by heat welding.

[0145] Figure 18 illustrates a modified example of the expansion / contraction reduction mechanism 240. The modified expansion / contraction reduction mechanism 240 includes a pattern roll 246 and an anvil roll 248. The pattern roll 246 is a cylindrical rotating body rotatable around a rotation axis along the CD direction, and its outer circumferential surface can be heated. A portion of this outer circumferential surface is provided with multiple joining patterns 246p for forming the expansion / contraction reduction section 92, projecting radially outward. The anvil roll 248 is a cylindrical rotating body rotatable around a rotation axis along the CD direction, and is positioned opposite the outer circumferential surface of the pattern roll 246.

[0146] The pattern roll 246 and the anvil roll 248 rotate while sandwiching the continuous body (composite stretchable sheet) of the exterior member 20 being conveyed in the MD direction. Then, by applying heat from the pattern roll 246, a predetermined area of ​​the exterior member 20 can be heat-welded based on the joining pattern 246p, thereby forming the stretch reduction section 92.

[0147] Similarly, the sheet joining mechanism 230 may form the sheet joining portion 91 by heat welding. In this case, similar to the expansion / contraction reduction mechanism 240 in Figure 18, the sheet members are joined in the thickness direction by sandwiching the sheet members between a pattern roll having a predetermined joining pattern on its outer surface and an anvil roll (neither of which are shown) and performing heat welding. [Explanation of Symbols]

[0148] 1. Menstrual panties (panty-type absorbent article of the first embodiment), 2. Menstrual panties (panty-type absorbent article of the second embodiment), 1a Opening around the torso, 1b Opening around the legs, 10 Absorbent body, 11 Absorbent core, 12 Top sheet, 13 Second sheet, 14 Back sheet, 15 side seats, 20 Exterior components, 20fe both sides, 20be both sides, 21 Non-skin side sheet, 21ff Folded portion, 21bf Folded portion, 22 Skin-facing sheet, 23 Skin-facing sheet, 25f Elastic member around the body, 25b Elastic member around the body, 26 Extendable sheet, 27 Extendable sheet, 28 Skin-facing sheet, 29 Skin-facing sheet, 30 Leakage prevention wall section, 50 Absorbing elastic member, 60 Side joint, 91 Sheet joint, 92. Expansion reduction section, 200 manufacturing equipment; 210 heating mechanism, 211 Heated conveying roller, 220 Stretching mechanism, 221 gear roll, 221m mountain section, 221v valley section, 222 gear roll, 222m mountain section, 222v valley section, 230 sheet joining mechanism, 231 pattern roll, 231p joint pattern, 235 ultrasonic horn, 240 Extension reduction mechanism, 241 Pattern Roll, 242 Pattern Plate, 242p Bonding Pattern, 245 ultrasonic horn, 246 pattern roll, 246p bond pattern, 248 Anvil Roll, 1a Opening around the torso, 1b Opening around the legs, CL center position, LE expansion and securing area

Claims

1. A method for continuously manufacturing a first composite stretchable sheet having a first pitch in the transport direction or a second composite stretchable sheet having a second pitch in the transport direction, comprising a plurality of sheets including at least one stretchable sheet, laminated together, The first composite stretchable sheet is provided with stretch reduction regions where stretch stress is reduced at each first pitch, and the second composite stretchable sheet is provided with the stretch reduction regions at each second pitch. A conveying process for conveying the stretchable sheet and a non-stretchable sheet different from the stretchable sheet along the conveying direction, A sheet joining process in which the stretchable sheet, which has been stretched along the transport direction, and the non-stretchable sheet are joined together in a state where they are stacked in the thickness direction, A stretch reduction process that forms the stretch reduction region at each first pitch or second pitch in the conveying direction, It has, The expansion reduction region is formed by an expansion reduction mechanism comprising a pattern roll and a horn or anvil roll facing the pattern roll with the composite expansion sheet in between. The sheet joining process is performed by a sheet joining mechanism positioned at a distance from the pattern roll to the upstream side in the conveying direction. A method for manufacturing a composite stretchable sheet, characterized in that, when manufacturing the first composite stretchable sheet, the pattern roll rotates once while the first composite stretchable sheet is conveyed by a first pitch in the conveying direction to form the stretch reduction region, and when manufacturing the second composite stretchable sheet, the pattern roll rotates once while the second composite stretchable sheet is conveyed by a second pitch to form the stretch reduction region.

2. A method for manufacturing a composite stretchable sheet according to claim 1, A method for manufacturing a composite stretchable sheet, characterized in that the stretchable sheet is a stretchable nonwoven fabric and the non-stretchable sheet is a non-stretchable nonwoven fabric.

3. A method for manufacturing a composite stretchable sheet according to claim 2, A method for manufacturing a composite stretchable sheet, characterized in that, prior to the sheet joining process, a stretching process is performed on the stretchable sheet to impart stretchability along the conveying direction.

4. A method for manufacturing a composite stretchable sheet according to claim 1, The stretchable sheet is a stretchable film, and the non-stretchable sheet is a non-stretchable nonwoven fabric. A method for manufacturing a composite stretchable sheet, characterized in that, in the sheet joining process, the non-stretchable sheet is joined to both sides of the stretchable sheet in the thickness direction.

5. A method for manufacturing a composite stretchable sheet according to any one of claims 1 to 4, A method for manufacturing a composite stretchable sheet, characterized in that the stretch reduction region is formed in the portion that overlaps with the sheet joint formed in the sheet joining process when viewed in the thickness direction.

6. A method for manufacturing a composite stretchable sheet according to claim 5, The sheet joining mechanism is capable of changing the range over which the stretchable sheet and the non-stretchable sheet are joined in a direction perpendicular to the conveying direction. A method for manufacturing a composite stretchable sheet, characterized in that the stretch reduction mechanism can change the range in which the stretch reduction region is formed in the intersecting direction.

7. A method for manufacturing a composite stretchable sheet according to any one of claims 1 to 4, A method for manufacturing a composite stretchable sheet, characterized in that, in the stretch reduction treatment, seal bonding and ultrasonic welding are performed.

8. A method for manufacturing a composite stretchable sheet according to any one of claims 1 to 4, In the aforementioned sheet joining process, seal joining and ultrasonic welding are performed. The aforementioned stretchable sheet is a stretchable nonwoven fabric, A method for manufacturing a composite stretchable sheet, characterized in that ultrasonic welding is performed from the side facing the stretchable sheet in the thickness direction.

9. A method for manufacturing a composite stretchable sheet according to any one of claims 1 to 4, The speed at which the stretchable sheet and the non-stretchable sheet, which are stacked in the thickness direction, are conveyed in the conveying direction, A method for manufacturing a composite stretchable sheet, characterized in that the rotation speed of the pattern roll is different from that of the pattern roll.

10. A method for manufacturing a composite stretchable sheet according to claim 9, A method for manufacturing a composite stretchable sheet, characterized in that, when forming the stretch reduction region, the pattern roll rotates such that, in the conveying direction, the stretch ratio per unit length of the stretchable sheet and the non-stretchable sheet upstream of the pattern roll is different from the stretch ratio per unit length of the stretchable sheet and the non-stretchable sheet downstream of the pattern roll.

11. A method for manufacturing a composite stretchable sheet according to claim 10, A method for manufacturing a composite stretchable sheet, characterized in that, when forming the stretch-reducing region, the stretchable sheet and the non-stretchable sheet are not wrapped around the outer surface of the pattern roll.

12. A method for manufacturing a composite stretchable sheet according to any one of claims 1 to 4, In the aforementioned conveying direction, it is possible to manufacture a third composite stretchable sheet having a third pitch that is an intermediate length between the first pitch and the second pitch. A method for manufacturing a composite stretchable sheet, characterized in that the length of the pattern roll in the circumferential direction is the same as the length of the third pitch.

13. A method for manufacturing a composite stretchable sheet according to any one of claims 1 to 4, A method for manufacturing a composite stretchable sheet, characterized in that, in the transport direction, the length of the stretch reduction region is 1 / 2 or less of the shorter of the first pitch and the second pitch.

14. A method for manufacturing a composite stretchable sheet according to any one of claims 1 to 4, A method for manufacturing a composite stretchable sheet, characterized in that the rotation speed of the pattern roll is periodically varied, and at least when forming the stretchable / non-stretchable region, the speed at which the stretchable sheet and the non-stretchable sheet are conveyed in the conveying direction is the same as the rotation speed of the pattern roll.

15. A method for manufacturing a composite stretchable sheet according to any one of claims 1 to 4, A method for manufacturing a composite stretchable sheet, characterized in that the stretch reduction region is formed by cuts or openings in the stretch reduction process.

16. A composite stretchable sheet manufacturing apparatus for continuously producing a first composite stretchable sheet having a first pitch in the conveying direction or a second composite stretchable sheet having a second pitch in the conveying direction, comprising a plurality of sheets including at least one stretchable sheet laminated together, The first composite stretchable sheet is provided with stretch reduction regions where stretch stress is reduced at each first pitch, and the second composite stretchable sheet is provided with the stretch reduction regions at each second pitch. A conveying mechanism for conveying the stretchable sheet and a non-stretchable sheet different from the stretchable sheet along the conveying direction, A sheet joining mechanism that joins the stretchable sheet, which is stretched along the transport direction, and the non-stretchable sheet in a state where they are stacked in the thickness direction, A stretch reduction mechanism that forms the stretch reduction region at each of the first or second pitches in the transport direction, It has, The aforementioned expansion / contraction reduction mechanism comprises a pattern roll and a horn or anvil roll facing the pattern roll with the composite expansion / contraction sheet in between. The sheet bonding mechanism is positioned at a distance from the pattern roll to the upstream side in the conveying direction. A composite stretchable sheet manufacturing apparatus characterized in that, when manufacturing the first composite stretchable sheet, the pattern roll rotates once to form the stretch reduction region while the first composite stretchable sheet is conveyed by a first pitch in the conveying direction, and when manufacturing the second composite stretchable sheet, the pattern roll rotates once to form the stretch reduction region while the second composite stretchable sheet is conveyed by a second pitch.

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