JP6902997B2 - Manufacturing method of absorbent articles - Google Patents

Description

The present invention relates to a method for producing an absorbent article.

There is known an absorbent article having a ventral side portion and a dorsal side portion, and both ends of the ventral side portion and the dorsal side portion in the width direction are joined by a pair of joint portions extending in the length direction. Then, as a method for producing the absorbent article, a method including a stacking step and a forming step is known. In the stacking step, a continuous sheet having a ventral continuous portion in which a plurality of ventral portions are connected in the width direction and a dorsal continuous portion in which a plurality of dorsal portions are connected in the width direction are provided on both sides in the length direction. While transporting the member in the transport direction so that the width direction is along the transport direction and the length direction is along the transverse direction, one of the ventral continuous portion and the dorsal continuous portion is overlapped with the ventral portion. It continuously forms a precursor of an absorbent article that overlaps the dorsal part. The forming step is performed on the ventral side by the first sandwiching member and the second sandwiching member including a plurality of convex portions arranged in the transverse direction at the upstream end portion of the precursor on the downstream side in the two precursors adjacent to each other in the transport direction. The portion and the dorsal portion are sandwiched and fused for an extremely short time to form a pair of joints straddling two adjacent precursors.

Examples of such a method include a sealing method disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2004-298413; US Patent Publication US2001545317 (A1)). In this sealing method, the soft work is temporarily sandwiched between the sealing facing surface having a plurality of convex portions in the rotating first sandwiching member and the sealing facing surface in the reciprocating second sandwiching member. The soft work is fused and sealed by the energy from the ultrasonic horn. An anvil embedded in a rotating body is used as the first holding member, and an ultrasonic horn is used as the second holding member. The soft work is a strip of a continuous sheet member including a sheet of a ventral continuous portion and a sheet of a dorsal continuous portion, in which one of the ventral continuous portion and the dorsal continuous portion is overlapped with the other, and is absorbent. It is a continuum in which precursors of articles are linked. A pair of joints is formed by fusing and sealing both ends of the precursor of the absorbent article in the transport direction.

Japanese Unexamined Patent Publication No. 2004-298413

In the sealing method of Patent Document 1, energy is applied to the continuous sheet member transported in the transport direction from the thickness direction to fuse the ventral side portion and the dorsal side portion of the continuous sheet member. Therefore, energy is applied to the continuous sheet member in a short time when the continuous sheet member is sandwiched between the sandwiching members so as not to hinder the movement of the continuous sheet member being conveyed in the transport direction, and fusion is performed in a short time. I have completed it.

Here, at each joint, a plurality of fused portions, that is, fused portions, are formed along the length direction (transverse direction). Each fused portion has a core portion fused while the continuous sheet member is pressed by the convex portion of the fusing and wearing provided on the sealing facing surface of the sandwiching member, and a continuous sheet so as to surround the core portion around the convex portion. It has an outer peripheral portion to which the members are fused. The locking strength (peeling strength or joining strength) of the fused portion largely depends on the size of the area of the fused portion when the continuous sheet member is viewed from the thickness direction, and therefore the core. It largely depends on the area of the portion and the outer peripheral portion. The locking strength becomes stronger as the area of the core portion and the outer peripheral portion becomes larger. The area of the outer peripheral portion becomes larger when the width (thickness) of the outer peripheral portion and the length of the outer circumference of the core portion are larger.

At this time, if all of the plurality of convex portions have the same shape, the areas of the plurality of convex portions viewed from the direction perpendicular to the seal facing surface are the same. In that case, since the areas of the plurality of core portions in the plurality of fused portions formed by the plurality of convex portions are the same, the locking strengths of the plurality of fused portions should be the same. However, according to the inventor's examination, it has been found that the locking strengths of the plurality of fused portions are not the same. Specifically, at the time of forming the fused portion, among the plurality of convex portions of the first holding member, the fused portion formed by the convex portion that initially abuts on the continuous sheet member has a relative locking strength. It gets lower. That is, the locking strength is relatively low at the fused portion of the continuous sheet member that is in contact with the convex portion near the head of the plurality of convex portions on the downstream side. On the other hand, the locking strength is relatively high in the fused portion formed by the convex portion that comes into contact with the continuous sheet member at the final stage. That is, the locking strength is relatively high at the fused portion of the continuous sheet member that is in contact with the convex portion near the tail end in the plurality of convex portions on the upstream side.

According to the inventor's examination, the reason why this phenomenon occurs can be considered as follows.
That is, in the sealing method of Patent Document 1, a stacking step of superimposing the ventral continuous portion and the dorsal continuous portion is performed immediately before the forming step of sandwiching and sealing the continuous sheet member with the sandwiching member while transporting the continuous sheet member in the transport direction. Be prepared. In the stacking process, for example, when the dorsal continuous portion is superposed on the ventral continuous portion, the dorsal continuous portion temporarily moves diagonally with respect to the transport direction, so that the dorsal continuous portion moves a longer distance than the ventral continuous portion. Will be done. Therefore, immediately after the stacking step, the tension of the dorsal continuous portion in the transport direction is higher than the tension of the ventral continuous portion, and the tension is different between the two continuous portions. In this state, when the forming step of sealing the continuous sheet member is started, when the continuous sheet member in contact with the convex portion near the head of the plurality of convex portions on the downstream side is fused, the dorsal continuous is strongly pulled. The part and the loose ventral continuous part are fused. Therefore, if the fusion time is short, the fusion portion cannot be sufficiently formed, and the locking strength is lowered. On the other hand, when the continuous sheet member in contact with the convex portion near the tail end of the plurality of convex portions on the upstream side is fused, the fused portion already formed by the plurality of convex portions on the downstream side is formed on the continuous sheet member. Being present, the difference in tension between the ventral and dorsal continuum is small. Therefore, even if the fusion time is short, the fusion portion can be sufficiently formed and the locking strength is increased.

As described above, when the locking strengths of the fused portion formed by the plurality of convex portions on the downstream side and the fused portion formed by the plurality of convex portions on the upstream side are different, the pair of joint portions of the absorbent article The left-right balance of the locking strength in the above becomes poor. In that case, after using the absorbent article, when the ventral part and the dorsal side are peeled off and removed at the pair of joints, the required force will be different, and there is no problem in the performance of the product. However, it may give the user the impression that it is a defective product.

In the method for producing an absorbent article, the present invention forms a pair of joints (or fused portions) across two adjacent absorbent articles after overlapping the ventral continuous portion and the dorsal continuous portion. Then, an object of the present invention is to provide a method for producing an absorbent article capable of suppressing a difference in locking strength between a pair of joints.

The method for producing an absorbent article of the present invention includes (1) a ventral portion and a dorsal portion, and a pair of joints in which both ends of the ventral portion and the dorsal portion in the width direction extend in the length direction. A method for manufacturing an absorbent article joined at a portion, wherein a plurality of ventral portions are connected in the width direction to a ventral continuous portion, and a plurality of dorsal portions are connected in the width direction to the dorsal side. The ventral side while transporting the continuous sheet members provided with the continuous portions on both sides in the length direction in the transport direction so that the width direction is along the transport direction and the length direction is along the transverse direction. A stacking step in which one of the continuous portion and the dorsal continuous portion is superposed on the other to continuously form a precursor of the absorbent article in which the ventral side portion and the dorsal side portion overlap each other, and the transport direction. In the first sandwiching member having a downstream convex portion row including a plurality of convex portions arranged in the transverse direction and an upstream convex portion row at the upstream end portion of the downstream precursor in the two precursors adjacent to the above. The ventral side portion and the dorsal side portion are sandwiched and fused by the downstream convex portion row and the second sandwiching member, and at the downstream end portion of the upstream precursor, the first sandwiching member The ventral side portion and the dorsal side portion are sandwiched and fused by the upstream side convex portion row and the second sandwiching member to form the pair of joint portions across the two adjacent precursors. The pair of joints obtained in the joining step comprising the joining step of forming is asymmetric with respect to the boundary line between the two adjacent precursors, and the upstream end of the downstream precursor. The joint portion of the portion includes a plurality of temporary fastening fusion portions arranged in the transverse direction, and a plurality of main fastening fusion portions located upstream of the plurality of temporary fastening fusion portions and arranged in the transverse direction. The junction of the downstream end of the upstream precursor includes a plurality of other fastening fusion sections arranged in the transverse direction, and the temporary fastening fusion section includes the main fastening fusion section and the main fastening fusion section. A manufacturing method having a smaller area than the other main fastening fused portion.

In the present manufacturing method, at the upstream end of the downstream precursor, which first abuts on the convex portion (in this case, the downstream convex portion row) of the first holding member, first, the temporary fastening fusion joint is continuous. Temporarily fasten the ventral and dorsal parts of the seat member. As a result, the base point of the tension can be set as the temporary fastening and fusion portion, that is, it can be located downstream from the position of the overlapping process of the ventral continuous portion and the dorsal continuous portion. As a result, it is possible to suppress the difference between the tension on the ventral side and the tension on the dorsal side of the continuous seat member on the downstream side of the temporary fastening and fusion portion. Therefore, after that, when the ventral side portion and the dorsal side portion of the continuous seat member are finally fastened by the main fastening fusion portion, the final fastening can be performed in a state where the difference in tension between the ventral side portion and the dorsal side portion is suppressed. As a result, the locking strength of the main fastening joint can be increased as compared with the case where the temporary fastening joint is not provided. As a result, it is possible to suppress the difference between the locking strength of the main fastening fused portion and the locking strength of the other main fastening fused portion, and to balance the locking strengths of both. Since the temporary fastening joint is provided for adjusting the tension in the forming process, it is not necessary to increase the locking strength. Therefore, the area of the temporary fastening joint is the main fastening joint or other parts. The area can be made smaller than the area of the temporarily fastened fused portion, and the locking strength can be reduced. Therefore, for example, when the locking strength of the main fastening fusion joint and the locking strength of another fastening fusion joint are balanced, the influence of the locking strength of the temporary fastening fusion joint can be suppressed to a low level. .. As described above, it is possible to suppress the difference in the locking strength of the pair of joints in the absorbent article.

The method for producing an absorbent article of the present invention is as follows: (2) The shape of each of the plurality of fastening joints is longer in the transport direction than in the transverse direction (1). ) May be used.
In the present manufacturing method, the shape of the main fastening fusing portion is vertically long in the transport direction, that is, the shape of the convex portion for the main fastening fusing portion in the downstream convex portion row is vertically long in the transport direction. Therefore, in the joining step, the time for the convex portion for the main fastening fused portion to come into contact with the continuous sheet member can be lengthened, and thus the time for forming the final fastening fused portion can be lengthened. As a result, the locking strength of the main fastening fused portion can be further increased, and the difference between the locking strength of the main fastening fused portion and the locking strength of the other main fastening fused portion is suppressed, and both are suppressed. The locking strength of the is more balanced.

In the method for producing an absorbent article of the present invention, (3) each of the plurality of temporary fastening joints and each of the plurality of main fastening fusion portions are displaced from each other in the transverse direction. The production method according to 1) or (2) may be used.
The continuous seat member in which the ventral continuous portion and the dorsal continuous portion are overlapped is fused in a state of being sandwiched between the second sandwiching member and the first sandwiching member. At that time, due to the relative speed difference between the second sandwiching member and the continuous sheet member, the continuous sheet member is relatively pressed against the surface of the second sandwiching member by the first sandwiching member and rubs the surface. Pass through. Due to the friction, the surface is continuously worn. Here, if at least a part of the temporary fastening and fusion portion and the main fastening fusion portion are present at the same position in the transverse direction, they are present at overlapping positions when viewed from the transport direction. In that case, the continuous sheet member pressed by the convex portion for the temporary fastening fusion portion passes through the same position in the transverse direction of the surface of the second holding member, and further pressed by the convex portion for the main fastening fusion portion. The continuous sheet member will pass through. In that case, wear at the same position on the surface of the second holding member increases, and a dent may occur in a part of the surface, for example, the fused state of the main fastening fused portion may become unstable. Therefore, in the present manufacturing method, the positions of the temporary fastening fusion joint and the main fastening fusion joint in the transverse direction are shifted from each other. As a result, the continuous sheet member pressed by the convex portion for the temporary fastening joint and the convex portion for the main fastening fusion portion are pressed to pass through the predetermined position on the surface of the second holding member in the transverse direction. It becomes one of the continuous sheet members. Therefore, it is possible to suppress an increase in wear at a predetermined position on the surface of the second sandwiching member, and it is possible to appropriately maintain a corresponding state between the second sandwiching member and the convex portion for the main fastening fusion portion. Therefore, it is possible to suppress a situation in which a dent is formed on a part of the surface of the second holding member and the fused state of the main fastening fused portion or the like becomes unstable, and the fused state can be stably maintained. As a result, the locking strength of the main fastening fused portion can be maintained high, and the difference between the locking strength of the main fastening fused portion and the locking strength of the other main fastening fused portion is suppressed, and both are suppressed. Locking strength can be balanced.

The method for producing an absorbent article of the present invention is as follows: (4) The length of the outer circumference of each of the plurality of fastening joints is longer than the length of the outer circumference of each of the other fastening fusion portions. , The production method according to any one of (1) to (3) above.
In the pair of joints formed across two adjacent precursors, the main fastening fusion part formed at the upstream end of the downstream precursor and the downstream end of the upstream precursor. If the area is the same as that of the other main fastening fusing portions formed, the main fastening fusing portion has a lower locking strength than the other main fastening fusing portions. The reason is that while the main fastening fusion section is formed in the portion of the continuous sheet member that abuts the convex portion (in this case, the row of convex portions on the downstream side) relatively first, the other fastening fusion portions are continuous. This is because it is formed in a portion of the seat member that abuts on the convex portion (in this case, the upstream convex portion row) relatively later. Therefore, in the present manufacturing method, each main fastening fusion joint is formed so that the length of the outer circumference of the main fastening fusion joint is longer than the length of the outer circumference of the other main fastening fusion joint. That is, the first narrowing member is formed so that the length of the outer circumference of the convex portion for the main fastening fusion portion is longer than the length of the outer circumference of the convex portion for the other main fastening fusion portion. As a result, the area of the main fastening fused portion can be relatively increased, and the locking strength can be further increased. Therefore, it is possible to suppress the difference between the locking strength of the main fastening fused portion and the locking strength of the other main fastening fused portion, and to balance the locking strengths of the two.

The method for producing an absorbent article of the present invention is as follows: (5) The joint portion of the downstream end portion of the precursor on the upstream side is located on the downstream side of the plurality of other main fastening fusion portions, and the cross section thereof. (1) to (4) above, further including a plurality of other temporary fastening fusion sections arranged in a direction, and the area of the other temporary fastening fusion section is smaller than the area of the other main fastening fusion section. The production method according to any one of the above items may be used.
In the present manufacturing method, in the continuous sheet member, not only the upstream end portion of the downstream precursor but also the downstream end portion of the upstream precursor has the ventral and dorsal portions of the continuous sheet member. First, it is temporarily fastened at another temporary fastening fusion splicing part, and then it is finally fastened at another main fastening fusion splicing part. Therefore, by temporarily fastening, the base point of the tension can be set to another temporary fastening fusion portion, so that the difference between the tension on the ventral side and the tension on the dorsal side of the continuous seat member is further suppressed, and the continuous seat member The ventral and dorsal parts can be permanently fastened. As a result, the locking strength of the joint can be improved even at the downstream end of the upstream precursor.

The method for producing an absorbent article of the present invention is as follows: (6) In the downstream convex portion row and the upstream convex portion row, the distance between the ends on one side in the transverse direction is the distance between the ends on the other side. The production method according to any one of (1) to (5) above, which is shorter than the distance.
In the present manufacturing method, the downstream convex row and the upstream convex row of the first holding member are substantially V-shaped (substantially widened, substantially V-shaped) when viewed from the height direction perpendicular to the transport direction and the transverse direction. It is formed in an inverted eight shape). Therefore, during the joining process, the continuous sheet member can be pressed almost always by the first sandwiching member and the second sandwiching member with respect to the transverse direction, the continuous sheet member can be prevented from being displaced in the transverse direction, and a pair of joining members can be stably joined. Can form a part. Therefore, it is possible to suppress the difference between the locking strength of the main fastening fused portion and the locking strength of the other main fastening fused portion, and to further balance the locking strengths of the two.

The method for producing an absorbent article of the present invention is as follows: (7) One side in the transverse direction is the leg side of the absorbent article, the other side in the transverse direction is the waist side of the absorbent article, and the downstream side. The production method according to (6) above, wherein the density of the plurality of convex portions in the transverse direction in the convex portion row and the upstream convex portion row is higher on the leg side of the absorbent article than on the waist side. But it may be.
On the side where the distance between the ends of the downstream convex row and the upstream convex row in the transverse direction is short, the distance between the downstream convex row and the upstream convex row in the transport direction is short. Therefore, the energy for the first holding member to be applied to the continuous sheet member is dispersed in the downstream convex portion row and the upstream convex portion row, and the energy per convex portion is reduced, so that the energy per fused portion is reduced. The locking strength may decrease. Therefore, in the present manufacturing method, the density of the plurality of convex portions is increased on the side where the distance between the end portions in the transverse direction is short. As a result, even if the energy per convex portion is small, the density of the convex portions is increased and the number of convex portions is increased so that sufficient locking strength can be obtained as a whole. As a result, the difference in locking strength between the downstream convex row and the upstream convex row can be suppressed, and the locking strength of the main fastening fusion joint and the locking of the other main fastening fusion joint can be suppressed. It is possible to suppress the difference from the strength and balance the locking strength between the two.

According to the present invention, in the method for producing an absorbent article, after overlapping the ventral continuous portion and the dorsal continuous portion, a pair of joints (or fusion portions) are formed across two adjacent absorbent articles. When forming, it is possible to suppress the difference in locking strength between the pair of joints.

It is a perspective view which shows the structural example of the disposable diaper which concerns on embodiment. It is a top view which shows the unfolded state of the disposable diaper of FIG. It is a partially enlarged plan view which shows the structural example of the joint part of the disposable diaper of FIG. It is a schematic diagram which shows the structural example of each fusion part of the joint part of FIG. It is a schematic diagram which shows the structural example of the cover sheet of the joint part of FIG. It is a schematic diagram which shows the structural example of the fusion apparatus which concerns on embodiment. It is a schematic diagram which shows the structural example of the convex part row of the anvil of the fusion device of FIG. It is a perspective view which shows the manufacturing method of the disposable diaper which concerns on embodiment. It is a schematic diagram which shows the formation process of the joint part in the manufacturing method of FIG. It is a schematic diagram which shows the other structural example of the convex part row of the anvil of the fusion device of FIG.

Hereinafter, a method for producing an absorbent article according to an embodiment of the present invention will be described of a pants-type disposable diaper (hereinafter, also simply referred to as “disposable diaper”) as an example of the absorbent article. However, the present invention is not limited to this example, and is applicable to various absorbent articles as long as it does not deviate from the scope of the subject matter of the present invention. Examples of such absorbent articles include so-called two-piece type disposable diapers.

First, the disposable diaper 1 according to the present embodiment will be described.
1 and 2 are diagrams showing a configuration example of the disposable diaper 1 according to the present embodiment. However, FIG. 1 is a perspective view showing a state when the disposable diaper 1 is used, and FIG. 2 is a plan view showing a state in which the disposable diaper 1 is unfolded. In the state shown in FIG. 2, the disposable diaper 1 has a length direction L perpendicular to each other, a width direction W, and a thickness direction T, and has a length extending in the length direction L through the center of the width direction W. It has a direction center line CL and a width direction center line CW that passes through the center of the length direction L and extends in the width direction W. Further, the direction toward the center line CL in the length direction and the direction away from it are defined as the inner direction and the outer direction of the width direction W, respectively. The direction toward the center line CW in the width direction and the direction away from it are defined as the inner direction and the outer direction of the length direction L, respectively. The view of the disposable diaper 1 placed on the plane surface including the length direction L and the width direction W from the upper side in the thickness direction T is called "planar view", and the shape grasped in the plan view is "planar shape". That is. The "skin side" and "non-skin side" mean the side relatively close to the wearer's skin surface and the side far from the skin surface in the thickness direction T of the disposable diaper 1 when the disposable diaper 1 is worn. These directions and the like are similarly applied to the flat state before using the disposable diaper 1 of FIG. 1, that is, the state where the disposable diaper 1 of FIG. 2 is folded along the folding line along the center line CW in the width direction.

The disposable diaper 1 is a pants-type diaper including a ventral portion 11, a dorsal portion 13, and an intermediate portion 12 between the ventral portion 11 and the dorsal portion 13. The ventral portion 11 is a portion of the disposable diaper 1 that is applied to the abdomen of the wearer. The intermediate portion 12 is a portion of the disposable diaper 1 that is applied to the crotch portion of the wearer. The dorsal side portion 13 is a portion of the disposable diaper 1 that is applied to the buttocks and / or the back portion of the wearer. Both ends 11a and 11b in the width direction W of the ventral side portion 11 and both ends 13a and 13b of the width direction W of the dorsal side portion 13 are overlapped in the thickness direction T along the length direction L, respectively. The pair of joining portions 14a and 14b join each other. Further, in the disposable diaper 1, the end portion 11e on the ventral side portion 11 opposite to the intermediate portion 12 in the length direction L and the end portion on the dorsal side portion 13 opposite to the intermediate portion 12 in the length direction L. With 13e, the waist opening WO is formed. Further, in the disposable diaper 1, a pair of leg openings LO and LO are formed by both side portions 12a and 12b of the intermediate portion 12 in the width direction W.

The disposable diaper 1 includes an absorbent body 10. The absorbent body 10 includes a liquid-permeable front surface sheet 2, a liquid-impermeable back surface sheet 3, and an absorber 4 located between the front surface sheet 2 and the back surface sheet 3. Examples of the surface sheet 2 include a liquid-permeable non-woven fabric and woven fabric, a synthetic resin film having liquid-permeable holes formed therein, and a composite sheet thereof. Examples of the back sheet 3 include a liquid-impermeable non-woven fabric, a synthetic resin film, a composite sheet thereof, and an SMS non-woven fabric. Examples of the absorber 4 include pulp fibers, synthetic fibers, and absorbent polymers. The absorber 4, the front surface sheet 2 and the back surface sheet 3 are bonded by an adhesive, respectively, and the front surface sheet 2 and the back surface sheet 3 are bonded by an adhesive at their peripheral edges. As the adhesive, a known material, for example, a hot melt adhesive can be used.

The disposable diaper 1 further includes a liquid-impermeable cover sheet 5. In the present embodiment, the cover sheet 5 includes a cover sheet 5a located on the skin side and a cover sheet 5b located on the non-skin side, which are laminated with each other in the thickness direction T and joined with an adhesive or the like. Further, in the present embodiment, both ends of the cover sheet 5b in the length direction L are folded back toward the skin so as to cover both ends of the cover sheet 5a in the length direction L. The cover sheets 5b and 5b at the folded positions on the ventral portion 11 and the dorsal portion 13 constitute the end portion 11e of the ventral side portion 11 and the end portion 13e of the dorsal side portion 13, respectively. On the surface of the cover sheet 5 on the skin side, the absorbent body 10 is arranged with the surface sheet 2 facing the skin side. In the disposable diaper 1, the cover sheet 5b forms the non-skin side surface of the disposable diaper 1, that is, the outer surface, and the surface sheet 2 and the cover sheet 5b of the end 11e and the end 13e form the skin side surface of the disposable diaper 1. That is, the inner surface is formed. Examples of the material of the cover sheet 5 include any liquid-impermeable sheet such as a liquid-impermeable non-woven fabric, a synthetic resin film, a composite sheet thereof, an SB non-woven fabric, and an SMS non-woven fabric. Examples of the material of the cover sheet 5 include polyolefin-based materials such as polypropylene and polyethylene. The basis weight of the cover sheet 5 is, for example, 5 to 100 g / m ² , preferably 10 to 50 g / m ² . The dimension (thickness) of the cover sheet 5 in the thickness direction T is, for example, 0.2 to 5 mm, preferably 0.2 to 2 mm. However, the cover sheet 5 may be one sheet or may not be folded back.

The disposable diaper 1 may further include a pair of liquid-impermeable leak-proof walls 6a, 6b and elastic members 8 (8a, 8b, 8c, 8d, 8e). The pair of leakage-proof walls 6a and 6b are arranged on both sides of the surface sheet 2 in the width direction W along the length direction L. The elastic member 8a and the elastic member 8b extend between the cover sheet 5a and the cover sheet 5b on the ventral side portion 11 and the dorsal side portion 13, respectively, in the width direction W and are arranged at intervals in the length direction L. Be held narrow. The elastic members 8a and 8b expand and contract the waist opening WO. The elastic member 8c is arranged so as to substantially follow the length direction L at both ends of the dorsal portion 13 side portion of the intermediate portion 12 in the width direction W, and to follow the width direction W at the central portion of the intermediate portion 12. Arranged continuously. The elastic member 8c expands and contracts the pair of leg openings LO and LO, respectively. An elastic member 8d and an elastic member 8e extending in the length direction L are arranged at the inner ends of the pair of leakage-proof walls 6a and 6b in the width direction W, respectively. The elastic members 8d and 8e expand and contract the leakage-proof walls 6a and 6b, respectively. Examples of the elastic member 8 include thread rubber.

Next, each configuration of the pair of joints 14a and 14b will be described.

FIG. 3 is a partially enlarged plan view schematically showing a configuration example of each of the pair of joints 14a and 14b in the disposable diaper 1. FIG. 3 is a view of the joint portions 14a and 14b of the disposable diaper 1 of FIG. 1 as viewed from the side of the dorsal side portion 13. The joint portion 14a is located on the right side when viewed from the side of the dorsal side portion 13, and the joint portion 14b is located on the left side when viewed from the side of the dorsal side portion 13. In FIG. 3, the description of the substantially central portion of the disposable diaper 1 in the width direction W will be omitted. In the joint portion 14a, at least a plurality of end portions 11a in the width direction W of the ventral side portion 11 and end portions 13a in the width direction W of the dorsal side portion 13 overlap in the thickness direction T along the length direction L. It is formed by being fused and joined at the points. Similarly, in the joint portion 14b, the end portion 11b in the width direction W of the ventral side portion 11 and the end portion 13b in the width direction W of the dorsal side portion 13 overlap in the thickness direction T along the length direction L. It is formed by fusing and joining at multiple points. The dimensions of the joint portions 14a and 14b in the length direction L and the width direction W are not particularly limited, and examples thereof include 50 to 250 mm and 3 to 20 mm, respectively.

The joint portions 14a and 14b include joint portions 20D and 20U in which a plurality of fused portions, that is, a plurality of fused portions, are arranged in a row at intervals along the length direction L, respectively. Therefore, the joining row 20D joins the end portion 11a and the end portion 13a, and the joining row 20U joins the end portion 11b and the end portion 13b. The overall arrangement of the joint row 20D and the joint row 20U is symmetrical with respect to the length direction center line CL. However, considering the arrangement of each of the plurality of fused portions, the joint row 20D and the joint row 20U are asymmetric with respect to the length direction center line CL, so that the pair of joint portions 14a and 14b are centered in the length direction. It is asymmetric with respect to the line CL.

The joints 14a and 14b have a waist side end region 21D and 21U including the waist opening WO side end and a leg side end region 23D including the leg opening LO side end, respectively, in the length direction L. , 23U and central regions 22D, 22U between waist side end regions 21D, 21U and leg side end regions 23D, 23U. The waist side end regions 21D and 21U and the leg side end regions 23D and 23U are 1/8 to 1/8 of the joint portion from the ends of the waist opening WO side and the leg opening LO side, respectively, in the length direction L. The area of the range of 3, and the central areas 22D and 22U are the remaining areas. However, the waist side end regions 21D and 21U and the leg side end regions 23D and 23U do not have to have the same length in the length direction L. In the present embodiment, the waist side end regions 21D and 21U, the central regions 22D and 22U, and the leg side end regions 23D and 23U are about 3/10, 4/10, and 3/10 of the joint, respectively. The area of the range.

In the present embodiment, the joint row 20D of the joint portion 14a is located on one side of the width direction W (left side in FIG. 3), and is a temporary fastening joint row 20Da extending in the length direction L and the other side in the width direction W. (Right side of FIG. 3), the main fastening joint row 20Db extending in the length direction is provided. The temporary fastening joint row 20Da includes a plurality of temporary fastening joints 21Da, 22Da, and 23Da arranged in the length direction L in the waist side end region 21D, the central region 22D, and the leg side end region 23D, respectively. On the other hand, the main fastening joint row 20Db includes a plurality of main fastening joints 21Db, 22Db, 23Db arranged in the length direction L in the waist side end region 21D, the central region 22D, and the leg side end region 23D. The structures of the plurality of temporary fastening joints 21Da, 22Da, and 23Da may be the same, or at least one of them may be different. The structures of the plurality of fastening joints 21Db, 22Db, and 23Db may be the same, or at least one of them may be different. Further, with respect to the plurality of temporary fastening joints 22Da, all or part of them (eg, a part on the LO side of the leg opening) may not be present. The same applies to the plurality of temporary fastening joints 23Da. This is to make it easier to peel off the fused portion of the joint when the disposable diaper 1 is removed after use.

On the other hand, in the present embodiment, the joint row 20U of the joint portion 14b is located on one side of the width direction W (left side in FIG. 3), and has a width different from that of the other temporary fastening joint row 20Ua extending in the length direction L. It is located on the other side of the direction W (on the right side of FIG. 3) and includes another main fastening joint row 20Ub extending in the length direction. The other temporary fastening joint row 20Ua has a plurality of other temporary fastening joints 21Ua, 22Ua, and 23Ua arranged in the length direction L in the waist side end region 21U, the central region 22U, and the leg side end region 23U, respectively. Including. On the other hand, the other fastening joint row 20Ub has a plurality of other fastening joints 21Ub, 22Ub arranged in the length direction L in the waist side end region 21U, the central region 22U, and the leg side end region 23U, respectively. Includes 23 Ub. The structures of the plurality of other temporary fastening joints 21Ua, 22Ua, and 23Ua may be the same, or at least one may be different. Alternatively, the structure of the plurality of other temporary fastening fusing portions 21Ua, 22Ua, and 23Ua may be omitted. The plurality of other fastening joints 21Ub, 22Ub, and 23Ub may be the same, or at least one may be different. Further, with respect to the plurality of temporary fastening joints 22Ua, all or part of them (eg, a part on the LO side of the leg opening) may not be present. The same applies to the plurality of temporary fastening joints 23Ua. This is to make it easier to peel off the fused portion of the joint when the disposable diaper 1 is removed after use.

In the present embodiment, the joining rows 20D and 20U of each region are both two rows. However, the number of joined rows 20D may be more than two rows, and the number of rows may be different for each region. On the other hand, the number of joined rows 20U may be one row, more than two rows, and the number of rows may be different for each region. Further, the number of regions may be one, two, or four or more.

The planar shapes of the fused portions 21Da to 23Da, 21Db to 23Db, 21Ua to 23Ua, and 21Ub to 23Ub are not particularly limited, and are, for example, a circle, an oval (rounded rectangle), an ellipse, a polygon, a star, and a linear shape. And so on. For example, the plane shapes of the temporarily fastened fused portions 21Da to 23Da and 21Ua to 23Ua include circles. At least one of those fused portions may have a different shape from at least one of the others. On the other hand, as the planar shape of the main fastening fused portions 21Db to 23Db and 21Ub to 23Ub, an elliptical circle (rounded rectangle) long in the width direction W can be mentioned. At least one of those fused portions may have a different shape from at least one of the others.

FIG. 4 is a schematic view showing a configuration example of each of the fused portions of the pair of joint portions 14a and 14b. FIG. 4A is a view of the fused portion viewed from the thickness direction T, and FIG. 4B is a sectional view taken along line VIb-VIb of FIG. 4A. The configuration of each fused portion is the same as the basic configuration, although the shape is different. The fused portion has a core portion BA and an outer peripheral portion BW formed so as to surround the core portion BA. The core portion BA is a portion that is pressed and fused by the convex portion when the fused portion is formed, and the outer peripheral portion BW is a portion that is fused around the convex portion at that time. The core portion BA is thin in the thickness direction T, and the outer peripheral portion BW is thick in the thickness direction T. The locking strength of the fused portion largely depends on the size of the area of the fused portion when viewed from the thickness direction T, and therefore largely depends on the areas of the core portion BA and the outer peripheral portion BW. The locking strength becomes stronger as the area of the core portion BA and the outer peripheral portion BW is larger. The area of the outer peripheral portion BW increases as the width (thickness) of the outer peripheral portion BW and the length of the outer circumference of the core portion BA increase.

With reference to FIG. 3, each of the plurality of temporary fastening joints 21Da to 23Da has a smaller area than each of the plurality of main fastening fusion portions 21Db to 23Db, and the outer circumference is shorter. For example, the temporary fastening fusion section 21Da has a smaller area than the main fastening fusion section 21Db, preferably the temporary fastening fusion section 22Da has a smaller area than the main fastening fusion section 22Db, and preferably the temporary fastening fusion section 23Da has a smaller area. The area is smaller than that of the main fastening fused portion 23Db. It is preferable that the temporary fastening and fusing portion 23Da has a smaller area than the main fastening and fusing portion 21Db. These relationships can be applied to the perimeter length as well. Therefore, each of the plurality of temporary fastening joints 21Da to 23Da has a smaller locking strength area than each of the plurality of main fastening joints 21Db to 23Db. As the size of each of the temporarily fastened fused portions 21Da to 23Da, when the shape is a circle, for example, a diameter of 0.5 to 5 mm can be mentioned. If the temporary fastening fused portion is less than 0.5 mm, the convex portion of the anvil used when forming the fused portion at the time of manufacturing is too small, and the convex portion is easily worn, which makes long-term production difficult. If the temporary fastening fusion part is larger than 5 mm, when removing the disposable diaper 1 after use, it is necessary to peel off both the large temporary fastening fusion part and the main fastening fusion part, which may make it very difficult to peel off. There is. As for the size of each of the fastening fusion portions 21Db to 23Db, in the case of an elliptical circle (rounded rectangle) whose shape is long in the width direction W as shown in FIG. 4, for example, the diameter (width) of the circular portion is 0.5 to Examples thereof include 5 mm and a rectangular portion having a length of 1 to 20 mm. The distance between the adjacent temporary fastening joint rows 20Da and the main fastening joint row 20Db is, for example, 1 to 10 mm, and the distance between the adjacent temporary fastening joints is, for example, 1 to 30 mm, and they are adjacent to each other. For example, the distance between the main fastening fused portions is 1 to 10 mm. The distance between adjacent fused portions may be constant or may change depending on the position. For example, the distance between the temporary fastening joint and the main fastening fusion portion is 1 to 30 mm. If the distance is less than 1 mm, the temporary fastening fusion part and the main fastening fusion part are too close to each other, so that the outer peripheral portions of both overlap each other, or the temporary fastening fusion part and the main fastening fusion part are being conveyed. There is a risk that it will be continuous due to misalignment. On the other hand, if the distance exceeds 30 mm, the elastic member may expand and contract when forming the joint during manufacturing, and the tension (described later) stabilized at the temporarily fastened joint may become unstable. is there.

In the present embodiment, each of the plurality of other temporary fastening fusing portions 21Ua to 23Ua has a smaller area and a shorter outer peripheral length than each of the plurality of other main fastening fusing portions 21Ub to 23Ub. For example, the other temporary fastening fusing portion 21Ua has a smaller area than the other main fastening fusing portion 21Ub, and preferably the other temporary fastening fusing portion 22Ua has a smaller area than the other main fastening fusing portion 22Ub, which is preferable. The area of the other temporary fastening joint 23Ua is smaller than that of the other main fastening joint 23Ub. It is preferable that the area of the other temporary fastening joint 23Ua is smaller than that of the other main fastening joint 21Ub. These relationships can be applied to the perimeter length as well. Therefore, each of the plurality of other temporary fastening fusing portions 21Ua to 23Ua has a smaller locking strength than each of the plurality of other main fastening fusing portions 21Ub to 23Ub. Examples of the size of each of the other temporary fastening joints 21Ua to 23Ua include a diameter of 0.5 to 5 mm when the shape is a circle. The reason is the same as in the case of the temporary fastening fused portions 21Da to 23Da. As for the size of each of the other fastening portions 21Ub to 23Ub, in the case of an elliptical circle (rounded quadrangle) whose shape is long in the width direction W as shown in FIG. 4, for example, the diameter (width) of the circular portion is 0. Examples thereof include 5 to 5 mm and a rectangular portion having a length of 1 to 20 mm. The distance between the other adjacent temporary fastening joint rows 20Ua and the other main fastening joint row 20Ub is, for example, 1 to 10 mm, and the distance between the other adjacent temporary fastening joint rows is, for example, 1 to 10 mm. The distance between the other adjacent main fastening joints is, for example, 1 to 10 mm. The distance between adjacent fused portions may be constant or may change depending on the position. The distance between the other temporary fastening fusing portions 21Ua to 23Ua and the other main fastening fusing portions 21Ub to 23Ub is, for example, 1 to 30 mm. The reason is the same as in the case of the temporary fastening fusing portions 21Da to 23Da and the main fastening fusing portions 21Db to 23Db.

As described above, considering the arrangement of the plurality of fused portions, the joining row 20D and the joining row 20U are asymmetric with respect to the center line CL in the length direction. Therefore, the temporary fastening joint row 20Da and the main fastening joint row 20Db and the other temporary fastening joint row 20Ua and the other main fastening joint row 20Ub are asymmetric with respect to the center line CL in the length direction. Therefore, a plurality of temporary fastening fusion portions 21Da to 23Da, a plurality of main fastening fusion portions 21Db to 23Db, a plurality of other temporary fastening fusion portions 21Ua to 23Ua, and a plurality of other final fastening fusion portions 21Ub to 23Ub. Is asymmetric with respect to the center line CL in the length direction.

In the present embodiment, the joint row 20D and the joint row 20U of the pair of joint portions 14a and 14b are formed by an ultrasonic sealing method. In the portion other than the portion where the joint row 20D and the joint row 20U are formed in the pair of joint portions 14a and 14b, all or a part thereof may be joined with, for example, an adhesive (example: hot melt adhesive). ..

FIG. 5 is a schematic view showing a configuration example of the cover sheet of the joint portion 14a of FIG. This figure schematically shows an example of a laminated state of the cover sheet 5 at the joint portion 14a seen from the end side in the width direction W. However, in this figure, the elastic members 8a, 8b, 8c are omitted. Since the joint portion 14b has the same end face shape as the joint portion 14a, the description thereof will be omitted. In the present embodiment, at the end portion 11a of the ventral side portion 11, the end portion of the cover sheet 5b on the waist opening WO side in the length direction L covers the end portion of the cover sheet 5a in the length direction L. , Folded back to the skin side. As a result, the end portion 11a includes a region A in which three layers of cover sheets of the cover sheet 5b, the cover sheet 5a and the folded cover sheet 5b are laminated, and a two-layer cover sheet of the cover sheet 5a and the cover sheet 5b. It has a laminated region B and. Similarly, at the end portion 13a of the back side portion 13, the end portion of the cover sheet 5b on the waist opening WO side in the length direction L covers the end portion of the cover sheet 5a in the length direction L on the skin side. It is folded back to. As a result, the end portion 13a has a region A in which the three-layer cover sheet is laminated and a region B in which the two-layer cover sheet is laminated. Then, as shown by the white arrows in the drawing, these end portions 11a and end portions 13a are laminated so as to overlap each other in the thickness direction T, and are fused at each fusion portion by a fusion apparatus (described later). , The joint portion 14a is formed by being joined. In the present embodiment, the end portion 11a and the end portion 13a are joined to each other in regions A and B. The size of the region A is not particularly limited, and examples thereof include 10 mm to 100 mm. The number of layers of the cover sheet 5 on each of the ventral side portion 11 and the dorsal side portion 13 is not particularly limited, and may be one layer or a plurality of layers. Further, the cover sheet 5 does not have to be folded back.

Next, a method for manufacturing the disposable diaper 1 according to the present embodiment will be described.
First, a fusing device for forming a joint used in the present manufacturing method will be described. FIG. 6 is a schematic view showing a configuration example of the fusion splicer according to the embodiment. The fusion device 90 includes a rotating body (not shown) having an anvil 92 (first holding member) having a seal facing surface 92a, and an ultrasonic horn 91 (second holding member) having a seal facing surface 91a. And. The anvil 92 is arranged in the rotating body so that the seal facing surface 92a substantially coincides with the outer peripheral surface of the rotating body. The seal facing surface 92a includes a downstream convex portion row 30D and an upstream convex portion row 30U in which a plurality of convex portions for forming a fused portion are arranged in a row. The downstream convex row 30D and the upstream convex row 30U are located on the downstream side and the upstream side in the transport direction MD of the precursor of the absorbent article during production, respectively. The plurality of convex portions of the downstream convex portion row 30D and the upstream convex portion row 30U extend along the transverse direction CD perpendicular to the transport direction MD. The seal facing surface 91a has an area facing at least one of the downstream convex portion row 30D and the upstream convex portion row 30U.

A precursor of the absorbent article is transported between the anvil 92 and the ultrasonic horn 91 in the transport direction MD along the outer peripheral surface of the rotating body. The anvil 92 and the ultrasonic horn 91 are relatively close to each other along the height direction TD substantially perpendicular to the transport direction MD. However, the ultrasonic horn 91 reciprocates by a predetermined range with respect to the direction along the outer peripheral surface of the rotating body including the anvil 92 (transportation direction MD). Here, the predetermined range is a range of a predetermined circumference (arc) along the outer peripheral surface, for example, the rotation angle of the corresponding rotating body is a range of 30 degrees or less, or, for example, the downstream side. The range is within 5 times the distance between the downstream end of the convex row 30D and the upstream end of the upstream convex row 30U. Therefore, the ultrasonic horn 91 moves (follows the outer peripheral surface) from the upstream side to the downstream side in the circumferential direction (conveying direction MD) by a predetermined range, sandwiches the precursor together with the anvil 92, and then from the precursor. It moves from the downstream side to the upstream side while being separated. When the ultrasonic horn 91 moves from the upstream side to the downstream side, the downstream convex portion row 30D of the seal facing surface 92a of the anvil 92 and the seal facing surface 91a of the ultrasonic horn 91 approach the height direction TD. Then, the ventral and dorsal parts of the precursor of the absorbent article are sandwiched and fused by ultrasonic vibration (and pressure) to form a joint row 20D. At the same time, the upstream convex portion row 30U of the seal facing surface 92a and the seal facing surface 91a sandwich the ventral side and the dorsal side of the precursor and are fused by ultrasonic vibration (and pressure). , Form a joint row 20U. At this time, the joining row 20D (on the right side in FIG. 3) of the downstream precursor of the two precursors arranged so that the transport direction MD is parallel to the width direction W and the joining row 20U (the joining row 20U) of the upstream precursor. (Left side of FIG. 3) and. The joining row 20D and the joining row 20U may be formed at the same time, or the joining row 20D may be formed first and the joining row 20U may be formed later. Examples of the fusing device 90 include the device of Patent Document 1. The ultrasonic horn 91 does not have to reciprocate in the transport direction MD.

FIG. 7 is a schematic view showing a configuration example of a convex row of the anvil 92 of the fusion splicer 90. The downstream convex row 30D and the upstream convex row 30U have the waist side end regions 31D and 31U, the leg side end regions 33D and 33U, and the waist side end regions 31D and 31U, respectively, in the transverse direction CD. It has a central region 32D, 32U between the leg side end regions 33D, 33U. The waist side end regions 31D and 31U correspond to the waist side end regions 21D and 21U of the joints 14a and 14b, respectively. The leg-side end regions 33D and 33U correspond to the leg-side end regions 23D and 23U of the joints 14a and 14b, respectively. The central regions 32D and 32U correspond to the central regions 22D and 22U of the joints 14a and 14b, respectively.

In the present embodiment, the downstream convex portion row 30D is located on the downstream side (left side in FIG. 7) of the transport direction MD, and the temporary fastening convex portion row 30Da extending in the transverse direction CD and the upstream side of the transport direction MD ( It is located on the right side of FIG. 7) and includes a main fastening convex row 30Db extending in the transverse direction CD. The temporary fastening convex portion row 30Da includes a plurality of temporary fastening convex portions 31Da, 32Da, 33Da arranged in the transport direction MD in the waist side end region 31D, the central region 32D, and the leg side end region 33D, respectively. On the other hand, the main fastening convex portion row 30Db includes a plurality of main fastening convex portions 31Db, 32Db, 33Db arranged in the transport direction MD in the waist side end region 31D, the central region 32D, and the leg side end region 33D, respectively. The structures of the plurality of temporary fastening protrusions 31Da, 32Da, 33Da may be the same, or at least one may be different. The structures of the plurality of fastening protrusions 31Db, 32Db, and 33Db may be the same, or at least one may be different. Further, for the plurality of temporary fastening convex portions 32Da, all or a part thereof (example: a part on the leg opening LO side) may not be present. The same applies to the plurality of temporary fastening convex portions 33Da. This is to make it easier to peel off the fused portion of the joint when the disposable diaper 1 is removed after use.

On the other hand, in the present embodiment, the upstream convex portion row 30U is located on the downstream side (left side in FIG. 7) of the transport direction MD, and the temporary fastening convex row 30Ua extending in the transverse direction CD and the upstream side of the transport direction MD. It is located on the side (right side in FIG. 7) and includes a main fastening convex row 30Ub extending in the transverse direction CD. The temporary fastening convex portion row 30Ua includes a plurality of temporary fastening convex portions 31Ua, 32Ua, and 33Ua arranged in the transport direction MD in the waist side end region 31U, the central region 32U, and the leg side end region 33U, respectively. On the other hand, the main fastening convex portion row 30Ub includes a plurality of main fastening convex portions 31Ub, 32Ub, 33Ub arranged in the transport direction MD in the waist side end region 31U, the central region 32U, and the leg side end region 33U, respectively. The structures of the plurality of temporary fastening protrusions 31Ua, 32Ua, and 33Ua may be the same, or at least one may be different. Alternatively, the structure of the plurality of temporary fastening convex portions 31Ua, 32Ua, 33Ua may not be provided. The plurality of fastening protrusions 31Ub, 32Ub, and 33Ub may be the same, or at least one may be different. Further, for the plurality of temporary fastening convex portions 32Ua, all or a part thereof (example: a part on the leg opening LO side) may not be present. The same applies to the plurality of temporary fastening convex portions 33Ua. This is to make it easier to peel off the fused portion of the joint when the disposable diaper 1 is removed after use.

Each of the plurality of temporary fastening convex portions 31Da to 33Da has a smaller area than each of the plurality of main fastening convex portions 31Db to 33Db, and thus the outer peripheral length is shorter. Specifically, the temporary fastening convex portion 31Da has a smaller area than the main fastening convex portion 31Db, preferably the temporary fastening convex portion 32Da has a smaller area than the main fastening convex portion 32Db, and preferably the temporary fastening convex portion 33Da is a book. The area is smaller than the fastening convex portion 33Db. It is preferable that the temporary fastening convex portion 33Da has a smaller area than the main fastening convex portion 31Db. These relationships apply to the length of the perimeter as well. As the size of each of the temporary fastening convex portions 31Da to 33Da, when the shape is a circle, for example, a diameter of 0.5 to 5 mm can be mentioned. If the temporary fastening convex portion is less than 0.5 mm, the convex portion is too small and the convex portion is easily worn, which makes long-term production difficult. If the temporary fastening convex portion is larger than 5 mm, when removing the disposable diaper 1 after use, it is necessary to peel off both the large temporary fastening fusion portion formed by the convex portion and the main fastening fusion portion, which is very difficult. It may be difficult to peel it off. As for the size of each of the main fastening convex portions 31Db to 33Db, in the case of an elliptical circle (rounded rectangle) whose shape is long in the width direction W, for example, the diameter (width) of the circular portion is 0.5 to 5 mm, and the length of the rectangular portion is long. The diameter is 1 to 20 mm. The distance between the adjacent temporary fastening convex portions 30Da and the main fastening convex portion row 30Db is, for example, 1 to 10 mm, and the distance between the adjacent temporary fastening convex portions is, for example, 1 to 30 mm. For example, the distance between the fitting convex portions of the main fastening is 1 to 10 mm. The distance between adjacent convex portions may be constant or may change depending on the position. The distance between the temporary fastening convex portion and the main fastening convex portion is, for example, 1 to 30 mm. If the distance is less than 1 mm, the temporary fastening convex portion and the main fastening convex portion are too close to each other, so that the temporary fastening fusion portion formed by both and the outer peripheral portion of the main fastening fusion portion may overlap or the temporary fastening portion may overlap. There is a risk that the fused portion and the final fastening fused portion will be continuous due to misalignment during transportation. On the other hand, if the distance exceeds 30 mm, the elastic member may be expanded or contracted when the joint portion is formed during manufacturing, and the tension stabilized at the temporarily fastened joint portion may become unstable.

In the present embodiment, each of the plurality of temporary fastening convex portions 31Ua to 33Ua has a smaller area than each of the plurality of final fastening convex portions 31Ub to 33Ub, and the outer peripheral length is shorter. Specifically, the temporary fastening convex portion 31Ua has a smaller area than the main fastening convex portion 31Ub, preferably the temporary fastening convex portion 32Ua has a smaller area than the main fastening convex portion 32Ub, and preferably the temporary fastening convex portion 33Ua is a book. The area is smaller than the fastening convex portion 33Ub. It is preferable that the temporary fastening convex portion 33Ua has a smaller area than the main fastening convex portion 31Ub. These relationships also apply to the length of the perimeter. As the size of each of the temporary fastening convex portions 31Ua to 33Ua, when the shape is a circle, for example, a diameter of 0.5 to 5 mm can be mentioned. The reason is the same as in the case of the temporary fastening convex portions 31Da to 33Da. As for the size of each of the main fastening convex portions 31Ub to 33Ub, when the shape is an elliptical circle (rounded rectangle) long in the width direction W, for example, the circular portion has a diameter (width) of 0.5 to 5 mm, and the rectangular portion has a rectangular portion. The length is 1 to 20 mm. The distance between the adjacent temporary fastening convex portions 30Ua and the main fastening convex portion row 30Ub is, for example, 1 to 10 mm, and the distance between the adjacent temporary fastening convex portions is, for example, 1 to 30 mm. For example, the distance between the fitting convex portions of the main fastening is 1 to 10 mm. The distance between adjacent convex portions may be constant or may change depending on the position. The distance between the temporary fastening convex portions 31Ua to 33Ua and the main fastening convex portions 31Ub to 33Ub is, for example, 1 to 30 mm. The reason is the same as in the case of the temporary fastening convex portions 31Da to 33Da and the main fastening convex portions 31Db to 33Db.

The downstream convex row 30D and the upstream convex row 30U are symmetrical with respect to the center line C1 extending in the transverse direction CD through the center of the transport direction MD on the seal facing surface 72a. However, considering the arrangement of the plurality of convex portions, the downstream convex portion row 30D and the upstream convex portion row 30U are asymmetric with respect to the center line C1. Therefore, the temporary fastening convex portion row 30Da and the main fastening convex portion row 30Db, and the temporary fastening convex portion row 30Ua and the main fastening convex portion row 30Ub are asymmetric with respect to the center line C1. Therefore, the plurality of temporary fastening convex portions 31Da to 33Da, the plurality of main fastening convex portions 31Db to 33Db, the plurality of temporary fastening convex portions 31Ua to 33Ua, and the plurality of final fastening convex portions 31Ub to 33Ub are relative to the center line C1. Is asymmetric.

In the present embodiment, the distance between the downstream convex row 30D and the upstream convex row 30U is the waist side end region 31D, the 31U side end W01, and the leg side end region 33D. At the end on the 33U side, it is W02, and the relationship between the two is W01 ≧ W02. Therefore, the downstream convex row 30D and the upstream convex row 30U have a substantially V shape (substantially widened shape, substantially inverted eight shape) when viewed from the height direction perpendicular to the transport direction MD and the transverse direction CD. Is formed in. The angle formed by both is preferably 0 to 20 degrees, and more preferably 2 to 10 degrees from the viewpoint of stable formation of the fused portion. However, if the angle formed by the two is larger than 20 degrees, the proportion of the pair of joints 14a and 14b in the disposable diaper 1 becomes large, and the material is wasted. Further, if the angle formed by the two is larger than 20 degrees, the width of the disposable diaper 1 near the waist opening WO and the width near the upper side of the leg opening LO will be significantly different, and it will be difficult to fit the wearer's body shape. ..

In the present embodiment, there are two rows each of the downstream convex row 30D and the upstream convex row 30U in each region. However, the number of the downstream convex row 30D may be more than two rows, and the number of rows may be different for each region. On the other hand, the upstream side convex row 30U may be one row, more than two rows, and the number of rows may be different for each region.

In the present embodiment, in the downstream convex portion row 30D (, upstream convex row 30U), the temporary fastening convex row 30Da (, 30Ua) is arranged in the downstream portion of the transport direction MD, and the upstream portion. The main fastening convex portion row 30Db (, 30Ub) is arranged in. As a result, the temporary fastening convex row 30Da is first sandwiched between the precursors of the absorbent articles being manufactured, and the final fastening convex row 30Db is subsequently sandwiched. Thereby, the temporary fastening can be first fused to the ventral and dorsal ends of the precursor, and then the final fastening can be fused. If the transport direction MD is in the opposite direction, the downstream convex portion row 30D and the upstream convex portion row 30U in FIG. 7 have shapes that are horizontally inverted with respect to the center line C1. Along with this, the joint row 20D and the joint row 20U in FIG. 3 have a shape that is horizontally inverted with respect to the center line CL in the length direction.

Next, a method for manufacturing the disposable diaper 1 according to the present embodiment will be described. FIG. 8 is a perspective view showing a manufacturing method of the disposable diaper 1 according to the embodiment, and shows a stacking step and a joining step in the present manufacturing method. Further, FIG. 9 is a schematic view showing a joining process in the manufacturing method of FIG. 8, that is, a forming process of the joining portions 14a and 14b. The present manufacturing method includes a stacking step and a forming step. Hereinafter, a specific description will be given.

First, the continuous sheet member 101a is formed by a conventionally known manufacturing method. However, in the continuous sheet member 101a, the ventral continuous portion 111 in which the plurality of ventral portions 11 are connected in the width direction W (transportation direction MD) and the plurality of dorsal portions 13 are connected in the width direction W (conveyance direction MD). The connected dorsal continuous portions 113 are provided on both sides in the length direction L (transverse direction CD). The continuous sheet member 101a includes an intermediate continuous portion 112 in which a plurality of intermediate portions 12 are connected in the width direction W (conveying direction MD) between the ventral continuous portion 111 and the dorsal continuous portion 113. Here, in the continuous sheet member 101a, the absorbent main body 10 is arranged on the ventral side portion 11, the intermediate portion 12, and the dorsal side portion 13 arranged in the length direction L (transverse direction CD), and these are integrally arranged. It can be regarded as the precursor 1a of the disposable diaper 1 (FIG. 2). That is, it can be considered that the continuous sheet member 101a has a structure in which the precursor 1a of the disposable diaper 1 (FIG. 2) in the unfolded state is connected in the width direction W (transportation direction MD). One end edge 111e side of the continuous sheet member 101a in the transverse direction CD includes an elastic member 108a for the elastic member 8a in the continuous sheet member 101a, and the other end edge 113e side is for the elastic member 8b. The elastic member 108b of the above is included. Further, the elastic members 108c and 108c for the elastic members 8c and 8c are arranged in the continuous sheet member 101a. The elastic members 108c and 108c extend in the transport direction MD while being curved in a wavy shape, respectively. The ends 12a and 12b that serve as the leg opening LO of the disposable diaper 1 are formed in the region surrounded by the elastic members 108c and 108c.

Next, a stacking step of stacking one of the ventral continuous portion 111 and the dorsal continuous portion 113 on the other is performed. That is, in the stacking step, the continuous sheet member 101a is transported in the transport direction MD so that the width direction W is along the transport direction MD and the length direction L is along the transverse direction CD, while being back to the ventral continuous portion 111. The side continuous portions 113 are overlapped, and the ventral side portion 11 and the dorsal side portion 13 are overlapped. In other words, the dorsal continuous portion 113 is folded on the ventral continuous portion 111 so that the edge 111e and the edge 113e of the transverse CD overlap. As a result, the precursor 1b of the absorbent article in which the ventral portion 11 and the dorsal portion 13 are overlapped is continuously formed. That is, a continuous sheet member 101b is formed in which the precursor 1b of the absorbent article is continuous in the transport direction MD. A known folding member (device) can be used to fold (overlap) the dorsal continuous portion 113 on the ventral continuous portion 111. In the stacking step, the ventral continuous portion 111 may be superposed on the dorsal continuous portion 113.

Next, a joining step of forming a pair of joining portions 14a and 14b in the region 20Q straddling the two precursors 1b and 1b adjacent to the transport direction MD is executed. In the joining step, first, the continuous sheet member 101b is supplied to the fusing device 90 and conveyed along the outer peripheral surface of the rotating body. Then, at the upstream end of the downstream precursors 1b in the two precursors 1b and 1b adjacent to the transport direction MD, the downstream convex portion row 30D of the anvil 92 (first holding member) and the ultrasonic horn 91 are formed. The ventral side portion 11 and the dorsal side portion 13 are sandwiched and fused with the (second sandwiching member) in an extremely short time to form the joint portion 14a. That is, in the joining step, first, the joining row 20D is formed. The joining step is further performed at the downstream end of the upstream precursor 1b in the two precursors 1b and 1b adjacent to the transport direction MD with the upstream convex row 30U of the anvil 92 (first sandwiching member). The ventral side portion 11 and the dorsal side portion 13 are sandwiched and fused with the ultrasonic horn 91 (second sandwiching member) in an extremely short time to form the joint portion 14b. That is, the joining step further forms a joining row 20U. As a result, a pair of joints 14a and 14b are formed across two adjacent precursors 1b and 1b. Then, by continuously performing the joining step, a continuous sheet member 101c in which the precursor 1c of the absorbent article including the pair of joining portions 14a and 14b is continuous in the transport direction MD is formed.
At this time, the continuous sheet member 101b is conveyed along the outer peripheral surface of the rotating body in the transport direction MD at a predetermined speed (example: 100 m / min.), And the ultrasonic horn 91 is predetermined along the outer peripheral surface of the rotating body. The ultrasonic horn 91 is pressed against the continuous sheet member 101b from the height direction TD perpendicular to the transport direction MD in a state where the rotation angle of the rotating body follows only within the range (example: the rotation angle of the rotating body is 25 degrees). Therefore, the contact between the ultrasonic horn 91 and the continuous sheet member 101b is performed by sandwiching and fusing in an extremely short time of, for example, about several tens of ms to 100 ms.

However, for example, a pair of transport rolls (not shown) arranged to face each other are provided on the upstream side and the downstream side of the transport direction MD with respect to the continuous sheet members 101a, 101b, and 101c shown in FIG. There is. Then, in the stacking step and the joining step, the continuous sheet members 101a, 101b, 101c are pulled by a predetermined tension in the transport direction MD between the pair of transport rolls on the upstream side and the downstream side, and the continuous sheet members 101a are pulled. Is processed into the continuous sheet member 101c via the continuous sheet member 101b.

Then, in the continuous sheet member 101c, the precursor 1c on the downstream side is cut along the boundary line C10 between the two adjacent precursors 1c and 1c. The boundary line C10 corresponds to a line extending in the transverse direction CD through the center of the transport direction MD between the joint row 20D and the joint row 20U. As a result, the disposable diaper 1 is manufactured.

Immediately before the forming step of sandwiching and sealing the continuous sheet member with the sandwiching member while transporting the continuous sheet member in the transport direction, when the stacking step of superimposing the ventral continuous portion and the dorsal continuous portion is performed, melting by the downstream convex portion row is performed. The locking strength of the landing portion becomes low, and the locking strength of the fused portion due to the row of convex portions on the upstream side increases. The reason is as follows. When the dorsal continuous portion is overlapped with the ventral continuous portion in the stacking step, the dorsal continuous portion temporarily moves diagonally with respect to the transport direction and moves a longer distance in the transport direction than the ventral continuous portion. In that case, immediately after the stacking step, the dorsal continuous portion is in a state of being pulled more than the ventral continuous portion, and thus a state of high tension is obtained. When the forming process is started in that state, when the continuous sheet member in contact with the convex portion near the head in the downstream convex portion row is fused, the dorsal continuous portion strongly pulled and the loose ventral continuous portion are fused. And are fused. Therefore, if the fusion time is short, the fusion portion cannot be sufficiently formed, and the locking strength is lowered. On the other hand, when the continuous sheet member in contact with the convex portion near the tail end in the upstream convex portion row is fused, the continuous sheet member already has the fused portion formed by the downstream convex portion row. The difference in tension between the dorsal continuous part and the ventral continuous part becomes small. Therefore, even if the fusion time is short, the fusion portion can be sufficiently formed and the locking strength is increased. Therefore, there is a possibility that an imbalance in the locking strength may occur between the fused portion by the downstream convex portion row and the fused portion by the upstream convex portion row.

However, in the present manufacturing method, it is possible to suppress an imbalance (difference) in the locking strength between the fused portion due to the downstream convex portion row and the fused portion due to the upstream convex portion row. First, in the present manufacturing method, at the upstream end portion of the precursor 1b on the downstream side of the transport direction MD, which first abuts on the convex portion (downstream side convex portion row 30D) of the anvil 92 (first holding member). Temporarily fasten the ventral side portion 11 and the dorsal side portion 13 of the continuous sheet member 101b with the temporary fastening fusing portion 21Da (~ 23Da). As a result, the base point of the tension can be set to the temporary fastening and fusion portion 21Da (~ 23Da), that is, a position downstream of the position of the stacking process of the ventral continuous portion 111 and the dorsal continuous portion 113. Therefore, it is possible to suppress the difference between the tension of the ventral side portion 11 and the tension of the dorsal side portion 13 of the continuous sheet member 101b on the downstream side of the temporary fastening fusional portion 21Da (~ 23Da). After that, in the present manufacturing method, the ventral side portion 11 and the dorsal side portion 13 of the continuous sheet member 101b are mainly fastened by the main fastening fusing portion 21Db (~ 23Db). At that time, since the main fastening can be performed while suppressing the difference in tension between the ventral side portion 11 and the dorsal side portion 13, the final fastening fusion joint portion is compared with the case where the temporary fastening fusion joint portion 21Da (~ 23Da) is not provided. The locking strength of 21Db (~ 23Db) can be increased. As a result, the difference between the locking strength of the main fastening fusing portion 21Db (~ 23Db) and the locking strength of the other main fastening fusing portion 21Ub (~ 23Ub) is suppressed, and the locking strength of both is balanced. be able to. As described above, it is possible to suppress the difference in the locking strength of the pair of joints 14a and 14b in the absorbent article such as the disposable diaper 1. Since the temporary fastening fusion splicing portion 21Da (~ 23Da) is provided for adjusting the tension in the forming step, it is not necessary to increase the locking strength, and therefore the temporary fastening fusing portion 21Da (~ 23Da) The area can be made smaller than the area of the main fastening fusing portion 21Db (~ 23Db) and other main fastening fusing portions 21Ub (~ 23Ub), and the locking strength can be reduced. Therefore, for example, in contrast to balancing the locking strength of the main fastening fusion splicer 21Db (~ 23Db) with the locking strength of the other final fastening fusion splicer 21Ub (~ 23Ub), the temporary fastening fusing portion 21Da The influence of the locking strength of (~ 23Da) can be suppressed to a low level.

In the present embodiment, as a preferred embodiment, the shape of each of the plurality of fastening joints 21Db (to 23Db) is longer in the transport direction MD than in the transverse direction CD.
In the present preferred embodiment, the shape of the main fastening fusing portion 21Db (to 23Db) is vertically long in the transport direction MD. That is, the shape of the convex portion (temporary fastening convex portion 31Da (~ 33Da)) for the main fastening fusion portion 21Db (~ 23Db) in the downstream side convex portion row 30D is vertically long in the transport direction MD. Therefore, in the joining step, it is possible to prolong the time for the convex portion (temporary fastening convex portion 31Da (~ 33Da)) for the final fastening welding portion 21Db (~ 23Db) to contact the continuous sheet member 101b, and thus the final fastening. The time for forming the fused portion 21Db (~ 23Db) can be lengthened. As a result, the locking strength of the main fastening fusing portion 21Db (~ 23Db) can be further increased, and the locking strength of the main fastening fusing portion 21Db (~ 23Db) and the other main fastening fusing portion 21Ub (~ 23Db) can be increased. The difference from the locking strength of 23Ub) can be suppressed, and the locking strength of both can be more balanced.

In the present embodiment, as a preferred embodiment, the positions of the CDs in the transverse direction are deviated from each of the plurality of temporary fastening joints 21Da (~ 23Da) and each of the plurality of final fastening fusion portions 21Db (~ 23Db). ..
The continuous sheet member 101b in which the ventral continuous portion 111 and the dorsal continuous portion 113 are overlapped with each other is fused by ultrasonic vibration (and pressure) while being sandwiched between the ultrasonic horn 91 and the anvil 92. At that time, due to the relative speed difference between the ultrasonic horn 91 and the continuous sheet member 101b, the continuous sheet member 101b is relatively pressed against the seal facing surface 91a of the ultrasonic horn 91 by the anvil 92 while facing the seal. It passes by rubbing the surface 91a. Due to the friction, wear progresses continuously on the seal facing surface 91a. Here, if at least a part of the temporary fastening fusion section 21Da (~ 23Da) and the main fastening fusion section 21Db (~ 23Db) exists at the same position of the transverse CD, they exist at overlapping positions when viewed from the transport direction MD. Will be done. In that case, the continuous sheet member 101b pressed by the temporary fastening convex portion 31Da (~ 33Da) passes through the same position of the cross-sectional direction CD of the seal facing surface 91a, and is further pressed by the main fastening convex portion 31Db (~ 33Db). The continuous sheet member 101b will pass through. If this happens, wear at the same position on the seal facing surface 91a will increase, and a dent will occur in a part of the seal facing surface 91a, for example, the fusion state of the final fastening fused portion 21Db (~ 23Db) may become unstable. There is. Therefore, as the present preferred embodiment, the positions of the temporary fastening fusing portion 21Da (~ 23Da) and the main fastening fusing portion 21Db (~ 23Db) in the transverse direction CD are shifted from each other. That is, the positions of the temporary fastening convex portion 31Da (~ 33Da) and the main fastening convex portion 31Db (~ 33Db) in the transverse direction CD are shifted from each other. As a result, the continuous sheet member 101b pressed by the temporary fastening convex portion 31Da (~ 33Da) and the main fastening convex portion 31Db (~ 33Db) are pressed to pass through the predetermined position of the cross-sectional direction CD of the seal facing surface 91a. It becomes one of the continuous sheet members 101b. Therefore, it is possible to suppress an increase in wear at a predetermined position on the seal facing surface 91a, and it is possible to appropriately maintain a corresponding state between the seal facing surface 91a and the main fastening convex portion 31Db (to 33Db). Therefore, it is possible to suppress a situation in which a dent is formed in a part of the seal facing surface 91a and the fusion state of the final fastening fusion portion 21Db (~ 23Db) or the like becomes unstable, and the fusion state can be kept stable. You can. As a result, the locking strength of the main fastening fusing portion 21Db (~ 23Db) can be maintained high, and the locking strength of the main fastening fusing portion 21Db (~ 23Db) and the other main fastening fusing portion 21Ub (~ 23Db) can be maintained. The difference from the locking strength of 23Ub) can be suppressed, and the locking strength of both can be balanced.

In the present embodiment, as a preferred embodiment, the length of the outer circumference of each of the plurality of fastening joints 21Db (~ 23Db) is the length of the outer circumference of each of the plurality of other fastening fusion portions 21Ub (~ 23Ub). It's longer than that. For example, in the pair of joints 14a and 14b formed over two adjacent precursors 1b and 1b, the main fastening fusion joint 21Db (~ 23Db) formed at the upstream end of the downstream precursor 1b ) And the other main fastening fusing portion 21Ub (~ 23Ub) formed at the downstream end of the upstream precursor 1b, if they have the same area (or the same outer peripheral length), the main fastening fusing portion. There is a possibility that the locking strength of 21Db (~ 23Db) is lower than that of other main fastening fusing portions 21Ub (~ 23Ub). The reason is that while the main fastening fused portion 21Db (to 23Db) is formed in the portion of the continuous sheet member 101b that abuts the convex portion (in this case, the downstream convex portion row 30D) relatively first, the other This is because the fastening fused portion 21Ub (to 23Ub) is formed at a portion of the continuous sheet member 101b that abuts on the convex portion (in this case, the upstream convex portion row 30U) relatively later. Therefore, as a preferred embodiment of the present invention, each main fastening portion 21Db (~ 23Db) has an outer peripheral length longer than the outer peripheral length of the other main fastening bonding portion 21Ub (~ 23Ub). The fused portions 21Db (~ 23Db) and 21Ub (~ 23Ub) are formed. That is, the length of the outer circumference of the convex portion for the main fastening fusing portion 21Db (~ 23Db) (the main fastening convex portion 31Db (~ 33Db) of the downstream convex portion row 30D) is the other main fastening fusing portion 21Ub ( The anvil 92 (first narrowing member) is formed so as to be longer than the outer peripheral length of the convex portion for (~ 23Ub) (the other main fastening convex portion 31Ub (~ 33Ub) of the upstream convex portion row 30U). As a result, the area of the main fastening fused portion 21Db (~ 23Db) can be relatively increased, and the locking strength can be further increased. Therefore, the difference between the locking strength of the main fastening fused portion 21Db (~ 23Db) and the locking strength of the other main fastening fused portion 21Ub (~ 23Ub) is suppressed, and the locking strength of both is balanced. Can be done.

In a preferred embodiment of the present embodiment, the joint portion (joint row 20U) of the downstream end portion of the upstream precursor 1b is located on the downstream side of the plurality of other main fastening fusion portions 21Ub (~ 23Ub). However, the area of the other temporary fastening joints 21Ua (~ 23Ua) includes the plurality of other temporary fastening fusion joints 21Ua (~ 23Ua) arranged in the transverse direction CD, and the area of the other temporary fastening joints 21Ua (~ 23Ua) is the other main fastening fusion joints 21Ub (~ 23Ua). It is smaller than the area of 23Ub). That is, in the present preferred embodiment, in the continuous sheet member 101b, not only the upstream end portion of the downstream precursor 1b but also the downstream end portion of the upstream precursor 1b is the ventral portion 11 of the continuous sheet member 101b. And the back side portion 13 are first temporarily fastened with another temporary fastening fusion splicing portion 21Ua (~ 23Ua), and then finally fastened with another main fastening fusion splicing portion 21Ub (~ 23Ub). Therefore, since the base point of the tension can be set to another temporary fastening fusion splicing portion 21Ua (~ 23Ua) by the temporary fastening, the difference between the tension of the ventral side portion 11 and the tension of the dorsal side portion 13 of the continuous sheet member 101b is further suppressed. In this state, the ventral side portion 11 and the dorsal side portion 13 of the continuous sheet member 101b can be permanently fastened. As a result, the locking strength of the joint portion 14b can be improved even at the downstream end portion of the upstream precursor.

In the preferred embodiment of the present embodiment, in the downstream convex row 30D and the upstream convex row 30U, the distance W02 between the ends on one side of the transverse CD is larger than the distance W01 between the ends on the other side. short. That is, in the present preferred embodiment, the downstream convex row 30D and the upstream convex row 30U of the anvil 92 (first narrowing member) are substantially V when viewed from the height direction perpendicular to the transport direction MD and the transverse CD. It is formed in the shape of (a shape that spreads toward the end, a shape that is roughly inverted eight). Therefore, during the joining process, the continuous sheet member 101b can always be pressed by the anvil 92 (first sandwiching member) and the ultrasonic horn 91 (second sandwiching member) with respect to the transverse CD, and the continuous sheet member 101b can be pressed. Can be made difficult to shift in the transverse direction CD, and a pair of joint portions 14a and 14b can be stably formed. Therefore, the difference between the locking strength of the main fastening fused portion 21Db (~ 23Db) and the locking strength of the other main fastening fused portion 21Ub (~ 23Ub) is suppressed, and the locking strength of both is more balanced. be able to. The angle formed by the downstream convex row 30D and the upstream convex row 30U is, for example, 0 to 20 degrees, and is preferably 2 to 10 degrees from the viewpoint of stable formation of the fused portion. If the angle formed by the two is larger than 20 degrees, the proportion of the pair of joints 14a and 14b in the disposable diaper 1 becomes large, and the material is wasted during manufacturing. Further, if the angle formed by the two is larger than 20 degrees, the width of the disposable diaper 1 near the waist opening WO and the width near the upper side of the leg opening LO will be significantly different, and it will be difficult to fit the wearer's body shape. ..

In the present embodiment, as a preferred embodiment, one side of the transverse CD is the leg side of the absorbent article (disposable diaper 1), the other side of the transverse CD is the waist side of the absorbent article, and the downstream convex portion. The density of the plurality of protrusions (31Da to 33Da and / or 31Db to 33Db, and / or 31Ua to 33Ua and / or 31Ub to 31Ub) of the transverse CD in the row 30D and the upstream convex row 30U is absorbable. The leg side of the article (disposable diaper 1) is higher than the waist side. For example, on the side where the distance between the ends of the transverse CDs in the downstream convex row 30D and the upstream convex row 30U is short, the convex portion of the transport direction MD of the downstream convex row 30D and the upstream convex row 30U. The distance between them is close. Therefore, the energy for the anvil 92 (first sandwiching member) to be applied to the continuous sheet member 101b is dispersed in the downstream convex portion row 30D and the upstream convex portion row 30U, and the energy per convex portion is reduced. , The locking strength per fused portion may decrease. Therefore, in the present preferred embodiment, the density of the plurality of convex portions is increased on the side where the distance between the end portions of the transverse CD is short. As a result, even if the energy per convex portion is small, a sufficient locking strength can be obtained as a whole by increasing the density of the convex portions, that is, increasing the number of convex portions. Thereby, the difference in the locking strength between the downstream convex portion row 30D and the upstream convex portion row 30U can be suppressed, and the locking strength of the main fastening fusion portions 21Db to 23Db and other main fastening fusion portions can be suppressed. It is possible to suppress the difference between the locking strengths of the landing portions 21Ub to 21Ub and balance the locking strengths of both.

In the convex row of the anvil 92 in FIG. 7, the downstream convex row 30D and the upstream convex row 30U have a substantially V shape (substantially V shape) when viewed from the height direction perpendicular to the transport direction MD and the transverse direction CD. It is formed in a divergent shape, approximately an inverted eight shape). However, as in the other configuration example of the convex row of the anvil 92 of the fusion splicer 90 shown in FIG. 10, both the downstream convex row 30D and the upstream convex row 30U are parallel to the transverse CD. There may be. In that case, in the disposable diaper 1 manufactured, the downstream convex row 30D and the upstream convex row 30U are asymmetric with respect to the center line C1, but compared to the V-shaped case, the wearer It can make it difficult to notice the asymmetry visually.

Hereinafter, the present invention will be described in more detail with reference to FIGS. 3, 4, and 7 with reference to Examples and Comparative Examples, but the present invention is not limited to such Examples. ..

(1) Sample The disposable diaper 1 of the example was manufactured by using the manufacturing method of the above embodiment. At that time, the pair of joints 14a and 14b shown in FIG. 3 was formed by using the anvil 92 having the downstream convex portion row 30D and the upstream convex portion row 30U shown in FIG. 7. The obtained sample was used as the sample of the example. On the other hand, the disposable diaper 1 of the comparative example was manufactured by slightly modifying the above manufacturing method. At that time, an anvil 92 having a downstream convex row 30D excluding the temporary fastening convex row 30Da and an upstream convex row 30U excluding the temporary fastening convex row 30Ua in FIG. 7 was used, and the temporary fastening joint in FIG. 3 was used. A pair of joints 14a and 14b having no row 20Da and a temporary fastening joint row 20Ua were formed. The obtained sample was used as a sample of a comparative example.

(2) Measurement of Width In the disposable diaper 1 of the embodiment produced in (1) above, each of the plurality of fastening joints 21Db in the waist side end region 21D of the joint row 20D of the joint 14a is shown in the figure. With respect to the positions P1 to P4 of the outer peripheral portion BW of 4 (a), the width of the cross section of the outer peripheral portion BW of FIG. 4 (b) was measured with an electron microscope and used as the width of the positions P1 to P4.
In the disposable diaper 1 of the comparative example produced in the above (1), for each of the plurality of main fastening fusing portions 21Db in the waist side end region 21D of the joining row 20D of the joining portion 14a, the outer circumference of FIG. 4 (a). With respect to the positions P1 to P4 of the parts BW, the width of the cross section of the outer peripheral part BW of FIG. 4B was measured with an electron microscope and used as the width of the positions P1 to P4.

(3) Measurement of Locking Strength of Joint 14a The locking strength (peeling strength or joint strength) of the joint 14a in each disposable diaper produced in (1) above is determined by the following test method. Measured by.
(I) From each disposable diaper, the joint portion 14a to which the ventral side portion 11 and the dorsal side portion 13 were bonded was taken out and cut into a width of 25 mm to prepare a locking strength test sample.
(Ii) Chuck (between chucks) of a tensile tester (model number AG-1kNI, manufactured by Shimadzu Corporation) at the ends of the ventral portion 11 and the dorsal portion 13 of the locking strength test sample in each length direction. It was sandwiched between 10 mm distances).
(Iii) With a tensile tester, the ventral side portion 11 and the dorsal side portion 13 of the locking strength test sample were pulled so as to be peeled off in the 180 ° direction, and the load value was measured.
(Iv) The maximum value of the measured load value was defined as the locking strength (N / 25 mm). The CV value of the locking strength was calculated by CV value = standard deviation of the locking strength / average value of the locking strength.
The above measurement results are shown in Table 1.

The sample of the example produced by using the anvil 92 having the downstream convex row 30D including the temporary fastening convex row is the anvil 92 having the downstream convex row 30D not including the temporary fastening convex row. The width of the main fastening fused portion was expanded as compared with the sample of the comparative example produced using the sample. Then, in the sample of the example, the locking strength of the main fastening fused portion was stronger than that of the sample of the comparative example, and the CV value of the locking strength was reduced. From the above, it was found that the locking strength of the fused portion can be improved and the variation in the locking strength can be suppressed by using the temporary fastening convex portion row.

(4) Measurement of the locking strength of each of the pair of joints 14a14b The locking strength of each of the pair of joints 14a and 14b (peeling off) in each disposable diaper of the example and the comparative example produced in (1) above. Strength or joint strength) was measured by the following test method.
(I) From each disposable diaper, the joint portion 14a and the joint portion 14b to which the ventral side portion 11 and the dorsal side portion 13 were bonded were taken out and cut into 25 mm widths to prepare a locking strength test sample.
(Ii) Chuck (between chucks) of a tensile tester (model number AG-1kNI, manufactured by Shimadzu Corporation) at the ends of the ventral portion 11 and the dorsal portion 13 of the locking strength test sample in each length direction. It was sandwiched between 10 mm distances).
(Iii) With a tensile tester, the ventral side portion 11 and the dorsal side portion 13 of the locking strength test sample were pulled so as to be peeled off in the 180 ° direction, and the load value was measured.
(Iv) The maximum value of the measured load value was defined as the locking strength (N / 25 mm). The CV value of the locking strength was calculated by CV value = standard deviation of the locking strength / average value of the locking strength.
The above measurement results are shown in Table 2.

The sample of the example produced by using the anvil 92 having the downstream convex row 30D including the temporary fastening convex row is the anvil 92 having the downstream convex row 30D not including the temporary fastening convex row. It was found that the difference in locking strength between the left and right joints was smaller than that of the sample of the comparative example produced using the sample. Then, the σ and CV values of the locking strength of the sample of the example were smaller than those of the sample of the comparative example. From the above, it was found that the difference in the locking strength of the pair of joints (fused portions) can be suppressed and the variation in the locking strength can be suppressed by using the temporary fastening convex portion row.

The method for producing an absorbent article of the present invention is not limited to each of the above-described embodiments, and can be appropriately combined or modified as long as it does not deviate from the object and purpose of the present invention. That is, the various techniques described in each embodiment can be applied to other embodiments as long as they do not conflict with each other.

1 Disposable diapers (absorbent articles)
1b Precursor 11 Ventral part 13 Dorsal part 14a, 14b Joint part 21Da Temporary fastening fusion part 21Db Main fastening fusion part 21Ub Other main fastening fusion part 91 Ultrasonic horn (second holding member)
92 Anvil (1st holding member)
101a, 101b continuous seat member 111 ventral continuous part 113 dorsal continuous part

Claims (7)

A method for producing an absorbent article, which comprises a ventral portion and a dorsal portion, and both ends of the ventral portion and the dorsal portion in the width direction are joined by a pair of joints extending in the length direction. There,
A continuous seat member including a ventral continuous portion in which a plurality of ventral portions are connected in the width direction and a dorsal continuous portion in which a plurality of dorsal portions are connected in the width direction on both sides in the length direction. One of the ventral continuous portion and the dorsal continuous portion is overlapped with the other while being transported in the transport direction so that the width direction is along the transport direction and the length direction is along the transverse direction. A stacking step of continuously forming a precursor of the absorbent article in which the ventral portion and the dorsal portion overlap.
A first having a downstream convex row and an upstream convex row including a plurality of convex portions arranged in the transverse direction at the upstream end of the downstream precursor in the two precursors adjacent to the transport direction. The ventral side portion and the dorsal side portion are sandwiched and fused by the downstream side convex portion row and the second sandwiching member in the sandwiching member, and at the downstream end portion of the upstream precursor, the first The pair of sandwiching members straddle the two adjacent precursors by sandwiching and fusing the ventral portion and the dorsal side portion by the upstream convex portion row and the second sandwiching member. With a joining process to form a joint,
The pair of joints obtained in the joining step is asymmetric with respect to the boundary between the two adjacent precursors.
The junction of the upstream end of the downstream precursor is
A plurality of temporary fastening joints arranged in the transverse direction, and
A plurality of main fastening fusion sections located upstream of the plurality of temporary fastening fusion sections and arranged in the transverse direction are included.
The junction of the downstream end of the upstream precursor is
Including a plurality of other fastening joints arranged in the transverse direction.
The temporary fastening fused portion has a smaller area than the main fastening fused portion and the other main fastening fused portion.
Production method. The shape of each of the plurality of fastening joints is longer in the transport direction than in the transverse direction.
The manufacturing method according to claim 1. Each of the plurality of temporary fastening fusion portions and each of the plurality of main fastening fusion portions are displaced from each other in the transverse direction.
The manufacturing method according to claim 1 or 2. The length of the outer circumference of each of the plurality of fastening joints is longer than the length of the outer circumference of each of the other fastening fusion portions.
The manufacturing method according to any one of claims 1 to 3. The junction of the downstream end of the upstream precursor is
It is located downstream of the plurality of other main fastening fusion sections, and further includes a plurality of other temporary fastening fusion sections arranged in the transverse direction.
The area of the other temporary fastening joint is smaller than the area of the other main fastening fusion joint.
The manufacturing method according to any one of claims 1 to 4. In the downstream convex row and the upstream convex row, the distance between the ends on one side in the transverse direction is shorter than the distance between the ends on the other side.
The manufacturing method according to any one of claims 1 to 5. One side in the transverse direction is the leg side of the absorbent article, and the other side in the transverse direction is the waist side of the absorbent article.
The density of the plurality of protrusions in the transverse direction in the downstream convex row and the upstream convex row is higher on the leg side of the absorbent article than on the waist side.
The manufacturing method according to claim 6.

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