JP7278738B2 - Elastic sheet manufacturing method and elastic sheet manufacturing apparatus - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stretch sheet manufacturing method and a stretch sheet manufacturing apparatus.

As a method of manufacturing a stretchable sheet, a method of attaching stretched rubber threads between sheets with an adhesive is known. On the other hand, in Japanese Patent Laid-Open No. 2002-100000, a sheet is pressed by passing a stretched rubber thread (wire-like element) between a folded portion and a non-folded portion of a sheet between a pair of rollers. A method of forming a connection is disclosed. A plurality of protrusions are intermittently formed on one roller in the direction of rotation and the direction of the rotation axis of the roller. Therefore, connecting portions are formed on both sides of the rubber thread so as to cross the rubber thread and intermittently in the stretching direction of the rubber thread. In the narrowed portion formed between the connecting portions on both sides of the rubber thread, the rubber thread in the untensioned state can be fixed and the rubber thread can be attached to the sheet. In this way, by attaching the rubber thread to the sheet without using an adhesive, it is possible to suppress deterioration in shrinkage performance of the rubber thread and deterioration in flexibility of the elastic sheet due to hardening of the adhesive.

Japanese Patent No. 3212615

However, in Patent Literature 1, the folded sheet and rubber thread are linearly fed between a pair of rollers without being wound around the rollers. Therefore, unless the position of the rubber thread in the direction of the rotation axis is adjusted with high accuracy, the rubber thread is supplied between the pair of rollers in a state where the rubber thread does not fit in the grooves between the protrusions arranged in the direction of the rotation axis, and the rubber thread is cut. end up

In particular, when the protrusions are arranged intermittently in the rotation direction of the roller, even if part of the rubber thread is wound around the roller, if the amount of winding is small, the gap between the protrusions adjacent to each other in the rotation direction, that is, the thread The thread rubber may be supplied to a position where there are no protrusions on both sides of the rubber. In that case, the position of the rubber thread in the rotation axis direction is difficult to be determined, and the upstream rubber thread is difficult to be guided to the groove. As a result, the rubber thread supplied onto the convex portion is supplied as it is between the pair of rollers, and the rubber thread is cut.

The present invention has been made in view of the above problems, and in the production of a stretchable sheet in which a rubber thread is interposed between the folded portion and the non-folded portion of the sheet, An object of the present invention is to suppress cutting of a rubber thread when forming a joint portion of sheets by using a pressure roller and a pressure bonding portion intermittently provided with a plurality of convex portions.

The main invention for achieving the above object is
interposing a rubber thread between the folded portion of the sheet and the non-folded portion of the sheet;
At the supply angle position in the rotation direction of the pressure roller provided with a plurality of intermittent protrusions in the direction of rotation and the direction of the rotation axis, the sheet and the rubber thread are not joined to each other, and the pressure roller a step of supplying to
A plurality of joint portions that are joined together by pressing the folded portion and the non-folded portion by using the pressure roller and the pressure bonding portion that contacts the pressure roller at the joining angle position in the rotational direction, and forming the plurality of joints for regulating the position of the rubber thread in the direction of expansion and contraction,
The plurality of convex portions have a first convex portion and a second convex portion adjacent to each other in the rotation direction,
The supply angular position and the joining angular position are more important than the angular difference between the angular position in the rotational direction at which the first convex portion is provided and the angular position in the rotational direction at which the second convex portion is provided. The angle difference between and is larger,
A portion of the sheet is folded back to one side in a predetermined direction to form the folded portion,
In the predetermined direction, the length of the folded portion is shorter than the length of the non-folded portion,
In the step of forming the joint portion, a second joint portion in which the folded portion and the non-folded portion are crimped and joined together, straddling the one end of the folded portion in the predetermined direction and forming the second joint portion so as not to overlap with the rubber thread .
Other features of the present invention will become apparent from the description of the specification and accompanying drawings.

According to the present invention, in the production of a stretchable sheet in which a rubber thread is interposed between a folded portion and a non-folded portion of a sheet, a pressing roller provided with a plurality of protrusions intermittently in the direction of rotation and the direction of the rotation axis. It is possible to suppress cutting of the rubber thread when forming the joint portion of the sheet using the and crimping portion.

1 is a plan view of a stretchable sheet 10 manufactured by the manufacturing method of this embodiment. FIG. FIG. 2A is a schematic cross-sectional view of the stretchable sheet 10 of FIG. 1, and FIG. 2B is a schematic cross-sectional view of the stretchable sheet 10 of a modification. FIG. 3A is a schematic perspective view of the underpants-type disposable diaper 1 using the elastic sheet 10, and FIG. 3B is a schematic plan view of the underpants-type disposable diaper 1 in the unfolded state and the stretched state. 1 is a schematic cross-sectional view of a stretch sheet manufacturing apparatus 20 in a first embodiment. FIG. FIG. 5A is an explanatory view of the surfaces of the anvil roller 25 and the horn roller 26, and FIG. 5B is a schematic enlarged view of the nearest portion between the anvil roller 25 and the horn roller 26. FIG. 6A and 6B are explanatory diagrams of a method of attaching the rubber thread 14 at the joint j. FIG. 7A is a schematic view of the elastic sheet manufacturing apparatus 20 viewed from above, and FIG. FIG. 2 is a schematic cross-sectional view of a stretch sheet manufacturing apparatus 20 in a second embodiment. FIG. 11 is a schematic cross-sectional view of a stretch sheet manufacturing apparatus 20 in a third embodiment.

At least the following matters will become apparent from the descriptions of this specification and the accompanying drawings.
a step of interposing a rubber thread between a folded portion of a sheet and a non-folded portion of the sheet; A step of supplying the sheet and the rubber thread to the pressure roller in a state in which the sheet and the rubber thread are not joined to each other at the supply angle position in the above, and contacting the pressure roller and the pressure roller at the joining angle position in the rotation direction. A plurality of joints are formed by crimping the folded portion and the non-folded portion by using a crimping portion that regulates the position of the rubber thread in the expansion and contraction direction. and wherein the plurality of protrusions have a first protrusion and a second protrusion adjacent to each other in the rotation direction, and the first protrusion in the rotation direction is provided. The expansion and contraction characterized in that the angular difference between the supply angular position and the bonding angular position is larger than the angular difference between the angular position and the angular position where the second convex portion is provided in the rotation direction. It is a method for manufacturing a sexual sheet.

According to such a stretchable sheet manufacturing method, the folded portion can be fastened to the non-folded portion by the joining portion, and the position of the rubber thread can be regulated. In addition, the rubber thread can enter the groove of the pressure roller before the rubber thread passes between the pressure roller and the pressure bonding section, making it easier to guide the upstream rubber thread into the groove. Therefore, it is possible to suppress cutting of the rubber thread at the time of forming the joint portion.

In the method for manufacturing such a stretchable sheet, part of the sheet is folded back in a predetermined direction to form the folded portion, and the length of the folded portion in the predetermined direction is greater than the length of the non-folded portion. In the supplying step, the sheet is supplied such that the non-folded portion is positioned closer to the pressure roller than the folded portion.

According to such a stretchable sheet manufacturing method, the non-folded portion that is long in the direction of the rotation axis directly winds around the pressure roller, so that the sheet can be conveyed stably. Therefore, the joining portion can be formed in a state in which the folded edge of the sheet is kept clean.

In the method for manufacturing such a stretchable sheet, a part of the sheet is folded back in a predetermined direction using a folding member to form the folded portion, and the folded portion is formed in the sheet conveying direction at the downstream side portion of the folding member. merging the rubber thread with the sheet along the line.

According to such a method for manufacturing a stretchable sheet, it is possible to prevent the movement of the rubber thread in the rotation axis direction from being restricted by the folding member, and the rubber thread can easily enter the grooves of the pressure roller.

In the method for manufacturing such a stretchable sheet, the thread rubber is interposed between the non-folded portion and the second sheet that overlaps one side of the non-folded portion in the thickness direction so that the second sheet is stretched. and feeding the laminate obtained by stacking the folded portion on the one side of the sheet in the thickness direction to the pressure roller.

According to such a method for manufacturing a stretchable sheet, it is possible to suppress positional deviation of each sheet and rubber thread included in the stretchable sheet.

In the method for producing such a stretchable sheet, a laminate obtained by laminating all other sheets of the stretchable sheet and the sheet is supplied to the pressure roller.

According to such a method for manufacturing a stretchable sheet, it is possible to suppress positional deviation of each sheet and rubber thread included in the stretchable sheet. Moreover, since the rubber thread and the sheet closer to the pressing roller than the rubber thread can be supplied at the same timing, the sheet easily bends into the groove of the pressing roller and the rubber thread easily enters the groove.

In the method for manufacturing such a stretchable sheet, at a pressing angle position on the upstream side of the joining angle position in the rotation direction, the folded portion is formed by using the pressure roller and a press roller in contact with the pressure roller. and a step of pressing the non-folded portion, wherein an angular position in the rotational direction at which the first convex portion is provided and an angular position in the rotational direction at which the second convex portion is provided. The angle difference between the supply angle position and the pressing angle position is larger than the angle difference between the supply angle position and the pressing angle position.

According to such a stretchable sheet manufacturing method, the rubber thread can enter the groove of the pressure roller before the rubber thread passes between the pressure roller and the press roller, and the upstream rubber thread is guided to the groove. easier to do. Therefore, it is possible to suppress cutting of the rubber thread at the time of forming the joint portion.

In the method for manufacturing such a stretchable sheet, the pressing step includes pressing the folded end of the sheet using the pressure roller and the press roller.

According to such a method for manufacturing a stretchable sheet, the joint portion can be formed while the folded end of the sheet is kept clean.

In the method for manufacturing such a stretchable sheet, a portion of the sheet is folded back to one side in a predetermined direction to form the folded portion, and in the predetermined direction, the length of the folded portion is equal to the length of the non-folded portion. a second joint portion that is shorter than the length of the folded portion and joins the folded portion and the non-folded portion to each other by crimping the folded portion and the non-folded portion in the step of forming the joint portion, the one of the folded portions in the predetermined direction forming the second joints arranged across the ends of the sides;

According to such a method for manufacturing a stretchable sheet, the ends of the folded portions are firmly joined to the non-folded portions, and peeling of the folded portions can be suppressed.

Further, an intervening portion for interposing a rubber thread between the folded portion of the sheet and the non-folded portion of the sheet, and a pressing roller provided with a plurality of convex portions intermittently in the rotation direction and the rotation axis direction, a supply unit that supplies the sheet and the rubber thread to the pressure roller in a state in which the sheet and the rubber thread are not joined to each other at the supply angle position in the rotation direction; the pressure roller at the joining angle position in the rotation direction; A plurality of joining portions for joining the folded portion and the non-folded portion to each other by pressing the folded portion and the non-folded portion using a pressing portion that contacts a pressing roller, the plurality of joining portions for regulating the position of the rubber thread in the stretching direction. a joint forming portion forming a joint, wherein the plurality of convex portions have a first convex portion and a second convex portion adjacent to each other in the rotational direction; The angular difference between the supply angular position and the joining angular position is greater than the angular position where the second convex in the rotational direction is provided and the angular position where the second convex is provided in the rotational direction. An elastic sheet manufacturing apparatus characterized by being large.

According to such a stretchable sheet manufacturing apparatus, the folded portion can be fastened to the non-folded portion by the joining portion, and the position of the rubber thread can be regulated. In addition, the rubber thread can enter the groove of the pressure roller before the rubber thread passes between the pressure roller and the pressure bonding section, making it easier to guide the upstream rubber thread into the groove. Therefore, it is possible to suppress cutting of the rubber thread at the time of forming the joint portion.

===Embodiment===
<<Configuration of elastic sheet 10>>
FIG. 1 is a plan view of a stretchable sheet 10 manufactured by the manufacturing method (manufacturing apparatus) of this embodiment. FIG. 1 is a diagram showing a state in which the elastic sheet 10 is stretched without wrinkles. FIG. 2A is a schematic cross-sectional view of the stretchable sheet 10 of FIG. 1, and FIG. 2B is a schematic cross-sectional view of the stretchable sheet 10 of a modification.

The stretchable sheet 10 has a stretch direction, a thickness direction, and a width direction which are orthogonal to each other. The elastic sheet 10 of FIG. 2A has a first sheet 11 and a second sheet 12 laminated in the thickness direction, a plurality of rubber threads 14, and a plurality of joints j. The other end of the first sheet 11 in the width direction is folded back along the stretch direction to one side in the width direction to cover a portion of the second sheet 12 . In the following description, the portion of the first sheet 11 that is folded back is referred to as a folded portion 11A, and the portion that is not folded back is referred to as a non-folded portion 11B.

The plurality of thread rubbers 14 are arranged side by side with intervals in the width direction between the first sheet 11 and the second sheet 12 while being made to extend along the stretching direction of the stretchable sheet 10 . The rubber thread 14 is attached to the first sheet 11 and the second sheet 12 in a stretched state. Therefore, the elastic sheet 10 is provided with elasticity in the direction along which the rubber thread 14 extends. As the thread rubber 14 (thread-like elastic member), in addition to thread-like natural rubber, various known synthetic rubbers such as styrene-based rubber, urethane-based rubber, ester-based rubber, polyurethane, and polyethylene can be applied.

The plurality of joints j are for bonding a plurality of sheets together by pressure bonding, and are intermittently arranged in the stretching direction and width direction of the stretchable sheet 10 . Also, the plurality of joints j regulates the position of the rubber thread 14 in the direction of expansion and contraction with respect to the first sheet 11 and the second sheet 12 . Although details will be described later, the position of the rubber thread 14 in the stretching direction is regulated by the pair of joints jP formed on both sides of the rubber thread 14 in the width direction. Although the planar shape of the joint j illustrated in FIG. 1 is a rectangular shape, the planar shape of the joint j is not particularly limited, and any shape such as an elliptical shape, a circular shape, a parallelogram shape, or the like can be adopted.

In addition, in the elastic sheet of the present embodiment, at least one sheet of the elastic sheet is partially folded back along the stretching direction (longitudinal direction of the rubber thread 14), and the folded portion of the sheet is folded back. It is sufficient that the rubber thread 14 is interposed between the non-folded portion. In FIG. 2A, part of the rubber thread 14a is interposed between the folded portion 11A and the non-folded portion 11B of the first sheet with the second sheet 12 interposed therebetween. In addition, as shown in FIG. 2B, a rubber thread 14 may be interposed between a folded portion 11A in which one sheet 11 is folded in half and a non-folded portion 11B. Moreover, in the stretchable sheet 10 shown in FIG. 2A , a part of the second sheet 12 may be folded together with the first sheet 11 . Moreover, the stretchable sheet may be a stretchable sheet in which another sheet or a plurality of sheets are laminated on the stretchable sheet 10 illustrated in FIGS. 2A and 2B.

<<Usage example of elastic sheet 10>>
FIG. 3A is a schematic perspective view of the underpants-type disposable diaper 1 using the elastic sheet 10. FIG. FIG. 3B is a schematic plan view of the underpants-type disposable diaper 1 in the unfolded and stretched state, viewed from the side of the skin. The stretchable sheet 10 manufactured by the manufacturing method (manufacturing apparatus) of the present embodiment is used, for example, as a component of absorbent articles such as disposable diapers.

The illustrated pants-type disposable diaper 1 (hereinafter also referred to as "diaper") comprises an absorbent main body 2 for absorbing and holding excrement, an abdominal waist portion 3 applied to the abdomen of the wearer, and the back of the wearer. and a dorsal waist portion 4 that is applied to the waist. As shown in the unfolded state of FIG. 3B , the central portion of the abdominal waist portion 3 in the left-right direction overlaps with the end portion on one side in the longitudinal direction of the absorbent body 2 , and the other side in the longitudinal direction of the absorbent body 2 . The center portion in the left-right direction of the back waist portion 4 overlaps the end portion. The diaper 1 in the unfolded state is folded in half at substantially the center in the longitudinal direction, and both sides of the abdominal waistline portion 3 in the left-right direction and both sides of the back waistline portion 4 in the left-right direction are joined by welding or the like. The diaper 1 becomes a pants type.

The ventral waist part 3 and the back waist part 4 are substantially rectangular members in a plan view, and a plurality of rubber threads 5 extending and contracting in the horizontal direction of the diaper 1 are arranged in a line with intervals in the vertical direction. . Therefore, the abdominal waist part 3 and the back waist part 4 can be stretched in the left-right direction of the diaper 1 and fit the wearer's waist. A stretchable sheet 10 can be used for the abdominal waist portion 3 and the back waist portion 4 . The stretching direction of the elastic sheet 10 corresponds to the horizontal direction of the diaper 1 , and the width direction of the elastic sheet 10 corresponds to the vertical direction of the diaper 1 .

When the stretchable sheet 10 is used as a component of an absorbent article, a soft sheet member can be exemplified as a sheet constituting the stretchable sheet 10 . Examples include nonwoven fabrics such as spunbond nonwoven fabrics and SMS (spunbond/meltblown/spunbond) nonwoven fabrics. Also, the sheet interposed between the sheets may be a stretchable sheet (stretchable film or stretchable nonwoven fabric) that is stretchable in the stretching direction of the stretchable sheet 10 . Moreover, not only the sheets interposed between the sheets, but also at least one of the sheet closest to the skin and the sheet closest to the skin may be made of a stretchable film or a stretchable nonwoven fabric.

Moreover, the elastic sheet 10 is not limited to be used for the ventral waist portion 3 and the back waist portion 4 . For example, the elastic sheet 10 can be used for leg gathers provided on both sides of the absorbent body in the lateral direction of the diaper so that the disposable diaper fits around the legs of the wearer. Since the leg gathers stretch in the longitudinal direction of the absorbent body, the longitudinal direction of the absorbent body corresponds to the stretching direction of the stretchable sheet 10 .

In addition, in a tape-type disposable diaper (not shown), fastening tapes (hook members) extend outward from the back waist portion in the left-right direction. The elastic sheet 10 can be used for the side panel for attaching the fastening tape to the back waist part. Since the side panels stretch in the lateral direction of the diaper, the lateral direction of the diaper corresponds to the stretching direction of the stretchable sheet 10 .

In addition, the stretchable sheet 10 is not limited to pants-type or tape-type disposable diapers, but can also be used as a component of absorbent articles such as pad-type disposable diapers, sanitary napkins, and shorts-type sanitary napkins. be. Moreover, it can be used not only for absorbent articles but also for masks, cleaning sheets, and the like.

=== Elastic sheet manufacturing apparatus and manufacturing method ===
<<First Embodiment>>
(Configuration of elastic sheet manufacturing apparatus 20)
FIG. 4 is a schematic cross-sectional view of the elastic sheet manufacturing apparatus 20 in the first embodiment. FIG. 5A is an illustration of the surfaces of the anvil roller 25 and the horn roller 26. FIG. FIG. 5B is a schematic enlarged view of the nearest portion of the anvil roller 25 and the horn roller 26. FIG. 6A and 6B are explanatory diagrams of a method of attaching the rubber thread 14 at the joint j. FIG. 7A is a schematic view of the elastic sheet manufacturing apparatus 20 viewed from above, and FIG. Hereinafter, the production apparatus 20 for the elastic sheet 10 shown in FIG. 2A will be described as an example.

The elastic sheet manufacturing apparatus 20 includes a conveying roller group 21 , an ultrasonic welding device 22 , a folding member 23 , and a discharge roller 24 . The stretchable sheet 10 is manufactured as a continuous sheet that is continuous in its stretching direction. In the elastic sheet manufacturing apparatus 20, the direction in which the materials are continuous is defined as the conveying direction, and the direction orthogonal to the conveying direction (that is, the width direction of the elastic sheet 10 and the materials) is defined as the CD direction.

The conveying roller group 21 is arranged on the upstream side in the conveying direction of the ultrasonic welding device 22 , conveys the material constituting the stretchable sheet 10 , and supplies the material to the ultrasonic welding device 22 . Specifically, the transport roller group 21 includes a first transport roller 211 that transports the continuum of the first sheet 11 , a second transport roller 212 that transports the continuum of the second sheet 12 , and a continuation of the rubber thread 14 . and a third transport roller 213 for transporting a plurality of bodies.

The first to third conveying rollers 211 to 213 are rotated around a rotation axis along the CD direction by a drive source (eg, motor) not shown. The first to third conveying rollers 211 to 213 may be a pair of rollers or a single roller. Alternatively, materials may be supplied to the ultrasonic welding device 22 by a belt conveyor or the like.

Hereinafter, the continuum of the first sheet 11, the continuum of the second sheet 12, the continuum of the rubber thread 14, and the continuum of the elastic sheet 10 are simply referred to as the first sheet 11, the second sheet 12, the rubber thread 14, It is also called elastic sheet 10 .

The ultrasonic welding device 22 is for forming the joint j of the stretchable sheet 10, and includes an anvil roller 25 (pressure bonding roller) arranged oppositely, and a horn roller 26 (pressure bonding portion) in contact with the anvil roller 25. ). The anvil roller 25 and the horn roller 26 are rotated around a rotation axis along the CD direction by a drive source (not shown). The anvil roller 25 and the horn roller 26 should be able to contact at least through a material passing between them, preferably without any material.

A plurality of protrusions 251 are formed on the outer peripheral surface of the anvil roller 25 as shown in FIG. 5A. The convex portion 251 and the horn roller 26 ultrasonically weld the material to form the joint j. Therefore, the protrusions 251 are arranged corresponding to the arrangement pattern of the joints j in the elastic sheet 10 .

The outer peripheral surface of the horn roller 26 is a smooth surface without irregularities, and vibrates in the direction of expanding and contracting the gap with the outer peripheral surface of the anvil roller 25 (that is, in the thickness direction of the material passing therebetween). The frequency of vibration is a predetermined value, for example, between 20 kHz and 40 kHz, and the amplitude is a predetermined value, for example, between 20 microns and 60 microns. Therefore, the surface of the horn roller 26 is ultrasonically vibrated. Such vibration is generated by, for example, inputting an electric signal of the above frequency to a piezo element of a converter (not shown) connected to the horn roller 26 .

Also, the first sheet 11 , the second sheet 12 and the rubber thread 14 pass between the anvil roller 25 and the horn roller 26 after being wound around the anvil roller 25 . The peripheral speed values of the first and second transport rollers 211 and 212 that transport the first and second sheets 11 and 12 are approximately the same as the peripheral speed value of the anvil roller 25, respectively. Therefore, the first and second sheets 11 and 12 are wound around the anvil roller 25 in a state in which they are substantially stretched and not slackened.

On the other hand, the peripheral speed value of the third transport roller 213 that transports the rubber thread 14 is 1/approximately the expansion ratio of the peripheral speed value of the anvil roller 25 . The extension ratio is a ratio R (R=E1/E0) that indicates how many times the total length E1 of the rubber thread 14 in the elastic sheet 10 in the stretched state is stretched over the total length E0 in the unloaded state, which is the natural length. . Therefore, while passing between the 3rd conveyance roller 213 and the anvil rollers 25, the thread rubber 14 is extended|stretched by said extension ratio, and it winds around the anvil roller 25 in the said extended state.

The folding member 23 is a member for folding the end portion of the first sheet 11 in the CD direction along the conveying direction, and as shown in FIG. 233. The upstream support portion 231 is a portion that supports the first sheet 11 that is conveyed in the horizontal direction. The downstream side support portion 232 changes the conveying direction of the first sheet 11 to a direction inclined with respect to the vertical direction (supply direction to the anvil roller 25), and moves the first sheet 11 and the second sheet joined thereto. 12 and the rubber thread 14. FIG. The bent portion 233 is a portion for forming the folded portion 11A by raising the end portion of the first sheet 11 in the CD direction and folding it so as to overlap with the non-folded portion 11B.

The discharge roller 24 is a roller that discharges the manufactured elastic sheet 10 to a downstream process. The discharge roller 24 is rotated around a rotation axis along the CD direction by a drive source (not shown).

(Manufacturing method of elastic sheet 10)
In the method of manufacturing the elastic sheet 10 by the manufacturing apparatus 20 having the above configuration, first, the first conveying roller 211 supplies the first sheet 11 to the folding member 23 . As shown in FIGS. 7A and 7B, a folding member 23 (intervening portion) is used to partially fold the first sheet 11 in the CD direction to form a folded portion 11A. On the other hand, the second conveying roller 212 and the third conveying roller 213 (intervening portion) join the second sheet 12 and the plurality of rubber threads 14 to the first sheet 11 supported by the downstream support portion 232 of the folding member 23. Let

Specifically, (part of) the second sheet 12 is interposed between the folded portion 11A and the non-folded portion 11B of the first sheet. A plurality of rubber threads 14 are interposed between the non-folded portion 11B of the first sheet and the second sheet 12 . A part of the rubber thread 14a is interposed between the folded portion 11A and the non-folded portion 11B of the first sheet with the second sheet 12 interposed therebetween.

In this way, a laminate 100 is formed in which all the sheets constituting the elastic sheet 10 are laminated with the rubber thread 14 interposed therebetween. Then, as shown in FIG. 4 , the laminate 100 is supplied to the anvil roller 25 at the supply angular position P1 in the rotation direction of the anvil roller 25 by the transport roller group 21 (supply unit). In the laminate 100, the folded portion 11A of the first sheet, the non-folded portion 11B, the second sheet 12, and the rubber thread 14 are not joined to each other. Specifically, no adhesive is applied to the first and second sheets 11 and 12 and the rubber thread 14, and the first and second sheets 11 and 12 are not pressure-bonded to each other.

After that, the anvil roller 25 rotates while wrapping the laminate 100 around the outer peripheral surface, and supplies the laminate 100 between the anvil roller 25 and the horn roller 26 . Then, at the joining angle position P2 in the rotation direction of the anvil roller 25, the ultrasonic welding device 22 (joint part forming part) ultrasonically welds the folded part 11A and the non-folded part 11B of the first sheet 11 and the second sheet 12. They are joined together by welding (pressing) to form a plurality of joints j. Thus, the elastic sheet 10 is manufactured.

Specifically, when the first and second sheets 11 and 12 and the rubber thread 14 pass between the anvil roller 25 and the horn roller 26 , the first and second sheets 11 and 12 are projected onto the anvil roller 25 . At a position corresponding to the portion 251, the ultrasonic vibration from the horn roller 26 is applied to melt and join. At this time, the rubber thread 14 is positioned in the grooves 252 (see FIGS. 5A and 5B) between the protrusions 251 adjacent in the CD direction on the outer peripheral surface of the anvil roller 25, and is not ultrasonically welded.

In FIG. 4, the rubber thread 14 is positioned on the convex portion 251 of the anvil roller 25 for the sake of clarity of the drawing. However, the rubber thread 14 is actually located in the groove portion 252 . The same applies to similar drawings to be described later.

Further, as shown in FIG. 2A, in the region of the non-folded portion 11B of the first sheet that overlaps with the folded portion 11A, the folded portion 11A of the first sheet, the non-folded portion 11B, and the second sheet 12 are joined at the junction j. joined by In other areas, the non-folded portion 11B of the first sheet and the second sheet 12 are joined by the joining portion j.

Further, as described above, the plurality of joints j serve to regulate the position of the rubber thread 14 in the direction of expansion and contraction with respect to the first sheet 11 and the second sheet 12. , 12 to attach the rubber thread 14 to them.

For this reason, in the present embodiment, as shown in FIG. 6A, in the CD direction, the distance Dj between the joint portion pair jP located on both sides of the rubber thread 14 is set to Assume that it is equal to or larger than the size D14 in the CD direction. Further, the interval Dj is assumed to be smaller than the dimension in the CD direction of the rubber thread 14 in the unloaded state, which is the natural length. The rubber thread 14 in the stretched state is thinner than the thickness of the rubber thread 14 in the natural state by the stretched amount. Therefore, when the continuous body of the rubber thread 14 is cut after the formation of the joint j and the stretched state of the rubber thread 14 is relaxed, as shown in FIG. The rubber thread 14, which is about to expand in the direction, can be pinched from the CD direction by the joint portion pair jP. As a result, the position of the rubber thread 14 in the stretching direction is regulated, and the rubber thread 14 is attached to the sheet.

In addition, the distance Dj between the joint portion jP may be smaller than the size D14 in the CD direction of the rubber thread 14 that is stretched when the joint portion j is formed. That is, the joining portion j may be formed while the rubber thread 14 is compressed by the space surrounded by the groove portion 252 of the anvil roller 25 and the horn roller 26 . Also, a part of the rubber thread 14 may be crimped together with the first and second sheets 11 and 12 by the protrusion 251 of the anvil roller 25 and the horn roller 26 . In these cases, when the joint j is formed (that is, before the stretched state of the rubber thread 14 is relaxed), the position of the rubber thread 14 in the stretching direction is regulated, and the rubber thread 14 is attached to the sheet. state.

Further, the pressure roller and the pressure bonding portion that form the joint portion j are not limited to the ultrasonic welding device 22, and may be any device capable of pressure-bonding a plurality of sheets and joining them to each other. For example, a heat sealer may be used to form the joint j (thermally welded portion). The heat-sealing device is a pair of heated rollers, one roller having a convex portion corresponding to the joint j on the outer peripheral surface, and the other roller having the convex portion on the smooth outer peripheral surface. can be exemplified.

As described above, in the manufacturing method of the present embodiment, the first sheet 11 and the rubber thread 14 are pressed together by the anvil roller while the rubber thread 14 is interposed between the folded portion 11A and the non-folded portion 11B of the first sheet. 25 to form junction j. By doing so, the folded part 11A of the first sheet can be fixed to the non-folded part 11B by the joining part j, and the rubber thread 14 can be attached to the folded part 11A and the non-folded part 11B of the first sheet.

In the elastic sheet 10 in which a part of the sheet is folded back, a folded edge 11C is formed as shown in FIG. 2A and the like. Therefore, when the stretchable sheet 10 is used for an absorbent article or the like, the curved folded end 11C can be brought into contact with the wearer's skin instead of the cut end of the sheet. Therefore, it can suppress that a wearer's skin is damaged.

Further, in the stretchable sheet 10 of the present embodiment, as shown in FIG. 1, the joints j are positioned on both sides of the rubber thread 14 in the width direction, and the joints j are intermittently formed in the stretch direction. By arranging the joints j at intervals in the stretching direction, it is possible to reduce the area of the highly rigid joints j, and to prevent the elastic sheet 10 from becoming highly rigid.

For this reason, a plurality of protrusions 251 are intermittently provided on the outer peripheral surface of the anvil roller 25 in the rotation direction (conveyance direction) and the rotation axis direction (CD direction). Among the plurality of protrusions 251 arranged in the rotation direction of the anvil roller 25, protrusions adjacent to each other in the rotation direction are referred to as a first protrusion 251a and a second protrusion 251b.

In the manufacturing method of the present embodiment, as shown in FIG. 4, in the rotation direction of the anvil roller 25, the angular position P3 at which the first convex portion 251a is provided and the second convex portion 251b are provided. It is assumed that the angular difference θ1 between the supply angular position P1 of the laminate 100 and the bonding angular position P2 is larger than the angular difference θ2 with the angular position P4 (θ2<θ1).

By doing so, the angle difference θ1 between the supply angular position P1 and the joining angular position P2 becomes larger than zero, and the laminate 100 is applied to the outer peripheral surface of the anvil roller 25 ( curved surface).

Therefore, even if the rubber thread 14 is supplied onto the convex portion 251 of the anvil roller 25, the rubber thread 14 does not roll on the surface of the anvil roller 25 in the CD direction before being supplied to the ultrasonic welding device 22. and can enter the groove 252 . Then, the rubber thread 14 is stably transported while being maintained in a state in which it enters the groove portion 252 . Therefore, it is possible to prevent the rubber thread 14 from being positioned on the convex portion 251 and pressed against the horn roller 26 and cut off. The first and second sheets 11 and 12 are also stably conveyed to the ultrasonic welding device 22 by winding around the outer peripheral surface of the anvil roller 25 .

However, on the outer peripheral surface of the anvil roller 25, the protrusions 251 are intermittently arranged in the rotation direction. Therefore, if the amount of the rubber thread 14 wound around the anvil roller 25 before being supplied to the ultrasonic welding device 22 is small (angle difference θ2>θ1), the distance between the convex portions 251 adjacent in the rotation direction ( The rubber thread 14 may be supplied to the region A) of FIG. 5A. In this case, the protrusions 251 do not exist on both sides of the rubber thread 14 in the CD direction, and it is difficult to determine the position of the rubber thread 14 in the CD direction. Therefore, the upstream rubber thread 14 is less likely to be guided to the groove portion 252 , and the rubber thread 14 supplied onto the convex portion 251 is easily supplied to the ultrasonic welding device 22 as it is. Then, the rubber thread 14 is cut.

On the other hand, in the present embodiment, the supply of the laminate 100 is greater than the angular difference θ2 between the angular positions P3 and P4 at which the first convex portion 251a and the second convex portion 251b adjacent in the rotation direction are provided. The angle difference θ1 between the angular position P1 and the joining angular position P2 is larger. Therefore, after being supplied to the anvil roller 25 and before being supplied to the ultrasonic welding device 22, the rubber thread 14 can pass between the protrusions 251 arranged in the rotation axis direction (can enter the grooves 252). ), the upstream rubber thread 14 is also easily guided to the groove portion 252 . Therefore, even if the rubber thread 14 is supplied onto the convex portion 251, it can enter the groove portion 252 before being supplied to the ultrasonic welding device 22, and cutting of the rubber thread 14 can be suppressed.

It should be noted that the angle difference θ1 is a virtual line that connects the center of rotation of the anvil roller 25 and the point where the laminate 100 starts contacting the anvil roller 25 in the cross section perpendicular to the CD direction of the manufacturing apparatus 20, and the anvil roller 25. It can also be said that the angle θ1 is formed between the center of rotation and the virtual line connecting the contact point between the anvil roller 25 and the horn roller 26 .

Similarly, the angle difference θ2 is the virtual line connecting the rotation center of the anvil roller 25 and the center of the first protrusion 251a in the cross section perpendicular to the CD direction of the manufacturing apparatus 20, and the rotation center of the anvil roller 25. , and the virtual line connecting the center of the second convex portion 251b. In addition, the first convex portion 251a and the second convex portion 252b are the same convex portion 251 forming the joint portion j for regulating the position of the rubber thread 14, that is, the convex portions whose positions in the CD direction are substantially the same. 251.

Also, in the present embodiment, the convex portions 251 are arranged at regular intervals in the rotation direction, but the present invention is not limited to this. When the intervals between adjacent projections 251 in the rotation direction are not constant, it is sufficient that θ1 is larger than the angle difference θ2 between the angular positions at which the projections 251 are provided, which is the minimum interval. .theta.1 is preferably larger than the angle difference .theta.2 between the angular positions at which the convex portions 251 are provided.

Further, as in the elastic sheet 10 shown in FIG. 1, when the length L1 of the folded portion 11A of the first sheet in the width direction (predetermined direction) is shorter than the length L2 of the unfolded portion 11B (L1<L2 ), in the step of supplying the laminate 100 to the anvil roller 25, it is preferable to supply the laminate 100 so that the non-folded portion 11B is positioned closer to the anvil roller 25 than the folded portion 11A.

By directly winding the unfolded portion 11B that is long in the width direction (CD direction) around the anvil roller 25 and conveying, the laminate 100 is conveyed more stably. Therefore, it is possible to suppress twisting of the sheet due to positional deviation in the conveying direction between the folded portion 11A and the non-folded portion 11B. In addition, the folded edge 11C (fold line) of the first sheet is conveyed in a state in which the folded edge 11C (fold line) is kept clean, and the joint portion j is formed. Therefore, it is possible to manufacture the elastic sheet 10 in which the sheet is folded back without being twisted.

In addition, in the step of interposing the rubber thread 14 between the folded portion 11A and the non-folded portion 11B of the first sheet, as shown in FIG. It is preferable to merge the rubber thread 14 with the first sheet 11 along the conveying direction of the one sheet 11 . That is, it is preferable to merge the rubber thread 14 with the first sheet 11 along the supply direction of the first sheet 11 to the anvil roller 25 .

By doing so, even when the upstream side support portion 231 and the downstream side support portion 232 are bent and arranged like the folding member 23 of the present embodiment, and the folding member 23 has the corner 234, the thread rubber 14 is fed to anvil roller 25 without contacting corner 234 of folding member 23 . Therefore, it is possible to suppress the movement of the rubber thread 14 from being restricted by the folding member 23, and the rubber thread 14 moves in the CD direction from when it is fed from the third transport roller 213 to when it is supplied to the anvil roller 25. can (can wobble). Therefore, even if the rubber thread 14 is supplied onto the convex portion 251, it can enter the groove portion 252, and it is possible to suppress the rubber thread 14 from being cut when forming the joint portion j.

In addition, in the present embodiment, in order to manufacture the elastic sheet 10 illustrated in FIG. 2A, the non-folded portion 11B of the first sheet and the second sheet 12 (which overlaps one side of the non-folded portion 11B in the thickness direction) ( 2nd sheet) with a thread rubber 14 interposed between them, and the folded portion 11A of the first sheet is superimposed on one side in the thickness direction of the second sheet 12, and the laminated body 100 is supplied to the anvil roller 25. do.

Therefore, compared with the case where the first sheet 11, the second sheet 12, and the rubber thread 14 are individually supplied to the anvil roller 25 and wound, positional deviation of each sheet and the rubber thread 14 in the CD direction can be suppressed. In addition, unlike the manufacturing method of the present embodiment, for example, the rubber thread 14 is interposed between the first sheet 11 and the second sheet 12, which are not partially folded, and then joined by the ultrasonic welding device 22. Simplification of the manufacturing process and manufacturing equipment of the elastic sheet 10 compared to the case where after forming the part j, part of the first sheet 11 is folded back and the folded part 11A is joined to the second sheet 12 with an adhesive. can. In addition, as described above, the joint portion (ultrasonic welding portion) for attaching the rubber thread 14 to the first and second sheets 11 and 12 and the joint portion (adhesive adhesive) for fixing the folded portion 11A of the first sheet to the second sheet 12 ), the elastic sheet 10 according to the manufacturing method of the present embodiment can have a smaller number of joints j, and the increase in rigidity of the elastic sheet 10 can be suppressed. Therefore, the flexibility of the elastic sheet 10 can be ensured, and deterioration of the shrinkage performance of the rubber thread 14 can be suppressed.

In addition, not only the elastic sheet 10 shown in FIG. 2A, but also when the elastic sheet 10 is composed of three or more sheets, a laminate obtained by laminating all the sheets of the elastic sheet 10 and the rubber thread 14 100 is preferably fed to anvil roller 25 . By doing so, all the sheets included in the stretchable sheet 10 can be joined by the joining portion j. Therefore, compared to the case where the joints of the sheets are different for each layer, the manufacturing process and manufacturing apparatus for the stretchable sheet 10 can be simplified, and the increase in rigidity of the stretchable sheet 10 can be suppressed.

In addition, compared to the case where the sheets and the rubber threads 14 of the stretchable sheet 10 are individually supplied to the anvil roller 25 and wound, feeding the laminate 100 allows the sheets and the rubber threads 14 to The position of is less likely to shift.

Further, the rubber thread 14 and the sheet positioned closer to the anvil roller 25 than the rubber thread 14 (here, the non-folded portion 11B of the first sheet) are supplied to the anvil roller 25 at the same timing. Therefore, compared to the case where the sheet arranged on the anvil roller 25 side is wound around the anvil roller 25 first, the sheet is more likely to bend into the groove 252 together with the rubber thread 14, and the rubber thread 14 is more likely to enter the groove 252. . Therefore, it is possible to prevent the rubber thread 14 from being cut when forming the joint j.

Moreover, in the elastic sheet 10, as shown in FIG. 2A and the like, it is preferable that the rubber thread 14 is not arranged at the folded end 11C of the sheet. By doing so, joint portions j can be formed on both sides in the CD direction of the rubber thread 14 closest to the folded end 11C, and the position of the rubber thread 14 can be firmly regulated. Further, since the rubber thread 14 is arranged with a space in the CD direction from the folded end 11C, the rubber thread 14 can move in the CD direction on the anvil roller 25, and the rubber thread 14 can easily enter the groove 252. . In addition, since the rubber thread 14 is not positioned at the folded end 11C, the folded end 11C can be made softer, so that the wearer's skin is not damaged when the shrinkable sheet 10 is used for an absorbent article or the like. can be suppressed.

Further, when the length L1 of the folded portion 11A of the first sheet folded to one side in the width direction is shorter than the length L2 of the non-folded portion 11B (L1 <L2), in the step of forming the joint j, the second joint j2 in which the folded portion 11A and the non-folded portion 11B are crimped and joined to each other, and the folded portion 11A in the width direction (CD direction) It is preferable to form a second joint j2 that straddles the one end 11Aa. By doing so, the end portion of the folded portion 11A is not turned over, and can be firmly joined to the non-folded portion 11B and the second sheet 12 . Therefore, peeling of the folded portion 11A can be suppressed.

Also, the second joint j2 is preferably different from the joints j arranged on both sides of the rubber thread 14 (that is, the joints j that regulate the position of the rubber thread 14). By doing so, even if the second joint j2 is peeled off, the rubber thread 14 is kept attached to the sheets 11 and 12 by the joint j. Therefore, the shrinkage performance of the elastic sheet 10 (rubber thread 14) can be maintained.

A second embodiment and a third embodiment will be described below. In the second and third embodiments, mainly different parts from the first embodiment will be explained.

<<Second Embodiment>>
FIG. 8 is a schematic cross-sectional view of a stretch sheet manufacturing apparatus 20 in the second embodiment. The manufacturing apparatus 20 of the second embodiment has press rollers 28 .

The press roller 28 is a roller arranged to face the anvil roller 25 on the upstream side in the transport direction from the horn roller 26 so as to be in contact with the anvil roller 25 . The press roller 28 is rotated around a rotation axis along the CD direction by a drive source (not shown). The anvil roller 25 and the press roller 28 should be able to contact at least through a material passing between them, preferably in a state in which there is no material.

In the manufacturing method using the manufacturing apparatus 20 of the second embodiment, the anvil roller 25 and the press roller 28 are used at the pressing angle position P5 on the upstream side of the joining angle position P2 in the rotation direction of the anvil roller 25. A step of pressing the folded portion 11A, the non-folded portion 11B, and the second sheet 12 of one sheet is included.

Specifically, the outer peripheral surface of the press roller 28 is a smooth surface without unevenness, and the press roller 28 contacts the convex portion 251 of the anvil roller 25 . Therefore, the folded portion 11A of the first sheet, the non-folded portion 11B, and the second sheet 12 are pressed by the press roller 28 at positions corresponding to the convex portions 251 of the anvil roller 25 . As a result, the sheets 11A, 11B, 12 and the rubber thread 14 can be firmly wound around the anvil roller 25, their positions in the CD direction are fixed, and they are stably conveyed.

When the manufacturing apparatus 20 has the press roller 28 in this manner, the angular difference θ2 between the angular positions P3 and P4 at which the first convex portion 251a and the second convex portion 251b adjacent to each other in the rotation direction of the anvil roller 25 are provided. It is preferable that the angular difference .theta.3 between the supply angular position P1 and the pressing angular position P5 is larger (.theta.2<.theta.3).

By doing so, the rubber thread 14 can pass between the protrusions 251 arranged in the rotation axis direction (entering the grooves 252) before passing through the press roller 25 after being supplied to the anvil roller 25. ), and the upstream rubber thread 14 is also easily guided to the groove portion 252 . After that, the rubber thread 14 is fixed in the groove 252 by the press roller 28 and is stably conveyed to the ultrasonic welding device 22 . Therefore, it is possible to prevent the rubber thread 14 from being cut when forming the joint j.

Moreover, it is preferable that the folded end 11</b>C of the first sheet pass between the anvil roller 25 and the press roller 28 and be pressed by the anvil roller 25 and the press roller 28 . By doing so, the folded end 11C (fold line) is kept neatly, and is conveyed to the ultrasonic welding device 20 to form the joint j. Therefore, it is possible to manufacture the elastic sheet 10 in which the sheet is folded back without being twisted.

<<Third Embodiment>>
FIG. 9 is a schematic cross-sectional view of a stretch sheet manufacturing apparatus 20 in the third embodiment. The third embodiment differs from the first embodiment in the ultrasonic welding device 22 . The ultrasonic welding device 22 is not limited to being composed of a pair of rollers. For example, as shown in FIG. 9, instead of the horn roller 26, a non-rotating horn 27 having a flat vibrating surface 27a arranged opposite the surface of the anvil roller 25 may be used. The vibrating surface 27a of the horn 27 vibrates in the direction of increasing or decreasing the distance between it and the surface of the anvil roller 25, thereby forming the joint j.
Further, although not shown, the outer peripheral surface of the horn roller 26 may be an uneven surface that meshes with the unevenness of the anvil roller 25 .

Although the embodiments of the present invention have been described above, the above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit and interpret the present invention. Further, the present invention can be modified and improved without departing from its spirit, and it goes without saying that the present invention includes equivalents thereof.

1 pants-type disposable diaper,
2 absorbent main body 3 ventral waist part 4 dorsal waist part 5 rubber thread
10 elastic sheet, 100 laminate,
11 first sheet (sheet),
11A folded portion, 11B non-folded portion, 11C folded end,
12 second sheet (second sheet), 14 thread rubber,
20 Elastic sheet manufacturing equipment,
21 transport roller group (supply unit, intermediate unit),
22 ultrasonic welding device (joint part forming part),
23 folding member (intervening portion), 24 discharge roller,
25 anvil roller (pressure roller),
251 convex portion, 251a first convex portion, 251b second convex portion,
252 groove,
26 horn roller (crimping part),
27 horn (crimping part), 28 press roller,
j junction, jP junction pair,
j2 second junction;

Claims (8)

interposing a rubber thread between the folded portion of the sheet and the non-folded portion of the sheet;
At the supply angle position in the rotation direction of the pressure roller provided with a plurality of intermittent protrusions in the direction of rotation and the direction of the rotation axis, the sheet and the rubber thread are not joined to each other, and the pressure roller a step of supplying to
A plurality of joint portions that are joined together by pressing the folded portion and the non-folded portion by using the pressure roller and the pressure bonding portion that contacts the pressure roller at the joining angle position in the rotational direction, and forming the plurality of joints for regulating the position of the rubber thread in the direction of expansion and contraction,
The plurality of convex portions have a first convex portion and a second convex portion adjacent to each other in the rotation direction,
The supply angular position and the joining angular position are more important than the angular difference between the angular position in the rotational direction at which the first convex portion is provided and the angular position in the rotational direction at which the second convex portion is provided. The angle difference between and is larger,
A portion of the sheet is folded back to one side in a predetermined direction to form the folded portion,
In the predetermined direction, the length of the folded portion is shorter than the length of the non-folded portion,
In the step of forming the joint portion, a second joint portion in which the folded portion and the non-folded portion are crimped and joined together, straddling the one end of the folded portion in the predetermined direction and forming the second joint portion so as not to overlap with the rubber thread . A method for manufacturing the elastic sheet according to claim 1,
A method for producing a stretchable sheet, wherein in the supplying step , the sheet is supplied such that the non-folded portion is positioned closer to the pressure roller than the folded portion. A method for manufacturing the elastic sheet according to claim 1 or 2,
forming the folded portion by folding a portion of the sheet in the predetermined direction using a folding member;
A method for producing a stretchable sheet, characterized in that the rubber thread joins the sheet along the conveying direction of the sheet on the downstream side of the folding member. A method for manufacturing the elastic sheet according to any one of claims 1 to 3,
The thread rubber is interposed between the non-folded portion and the second sheet overlapping the one side of the non-folded portion in the thickness direction, and the one side of the second sheet in the thickness direction A method for producing a stretchable sheet, characterized in that a laminate obtained by stacking the folded portion on top of the above is supplied to the pressure roller. A method for manufacturing the elastic sheet according to any one of claims 1 to 4,
A method for producing a stretchable sheet, comprising supplying a laminate obtained by laminating all other sheets of the stretchable sheet and the sheet to the pressure roller. A method for manufacturing the elastic sheet according to any one of claims 1 to 5,
A step of pressing the folded portion and the non-folded portion using the pressure roller and a press roller contacting the pressure roller at a pressing angle position on the upstream side of the joining angle position in the rotational direction. has
The supply angular position and the pressing angular position are more sensitive than the angular difference between the angular position in the rotational direction at which the first convex portion is provided and the angular position in the rotational direction at which the second convex portion is provided. A method for producing a stretchable sheet, wherein the angle difference between and is larger. A method for manufacturing the stretchable sheet according to claim 6,
A method for producing a stretchable sheet, wherein in the pressing step, a folded end of the sheet is pressed using the pressure roller and the press roller. an interposed portion for interposing a rubber thread between the folded portion of the sheet and the non-folded portion of the sheet;
At the supply angle position in the rotation direction of the pressure roller provided with a plurality of intermittent protrusions in the direction of rotation and the direction of the rotation axis, the sheet and the rubber thread are not joined to each other, and the pressure roller a supply unit for supplying to
A plurality of joint portions that are joined together by pressing the folded portion and the non-folded portion by using the pressure roller and the pressure bonding portion that contacts the pressure roller at the joining angle position in the rotational direction, , a joint forming part that forms the plurality of joints that regulate the position of the rubber thread in the stretching direction,
The plurality of convex portions have a first convex portion and a second convex portion adjacent to each other in the rotation direction,
The supply angular position and the joining angular position are more important than the angular difference between the angular position in the rotational direction at which the first convex portion is provided and the angular position in the rotational direction at which the second convex portion is provided. The angle difference between and is larger,
A portion of the sheet is folded back to one side in a predetermined direction to form the folded portion,
In the predetermined direction, the length of the folded portion is shorter than the length of the non-folded portion,
The joint forming portion is a second joint portion for crimping and joining the folded portion and the non-folded portion to each other, and straddles the end of the folded portion on the one side in the predetermined direction. An apparatus for manufacturing a stretchable sheet , wherein the second joint portion is formed so as not to overlap with the rubber thread .

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