CN109528397B

CN109528397B - Method for producing pants-type disposable diaper

Info

Publication number: CN109528397B
Application number: CN201811229241.8A
Authority: CN
Inventors: 杉山胜彦; 田代和泉
Original assignee: Oji Holdings Corp
Current assignee: Oji Holdings Corp
Priority date: 2013-06-03
Filing date: 2014-01-15
Publication date: 2021-05-14
Anticipated expiration: 2034-01-15
Also published as: EA030691B1; CN109528398B; EA201592116A1; TW201446223A; JP5360327B1; JP2014233466A; AU2014276240B2; SG11201509501UA; WO2014196215A1; KR20160021101A; KR101744036B1; NZ714235A; CN105324098B; MY176170A; CN109528397A; SG10201606752VA; BR112015029984A2; CN105324098A; HK1215528A1; TWI605804B

Abstract

The present invention provides a pants-type disposable diaper which has excellent appearance and excellent tactile sensation of side seals formed at the side edges of both left and right side portions of the diaper, and a method for manufacturing the same. A pair of side seals (4) are formed in a pants-type disposable diaper, and the pair of side seals (4) have a main joining region (40) extending in the vertical direction and a sub-joining region (50) located on the outer side of the main joining region (40) in the left-right direction and extending in the vertical direction. The sub-bonding region (50) is a region formed by arranging a plurality of sub-embossed sections (51) in a vertically spaced array, and the bonding strength of the sub-bonding region (50) is set to be weaker than the bonding strength of the main bonding region (40).

Description

Method for producing pants-type disposable diaper

The present application is a divisional application filed on 2014, 1/15, application No. 201480031554.6 entitled "pant-type disposable diaper and method of manufacturing the same".

Technical Field

The present invention relates to a disposable diaper to be worn in the crotch of a wearer and to absorb and support liquid such as urine, and a method for manufacturing the same. More specifically, the disposable diaper will be described in which the front body and the back body are joined at the side seal portions at the left and right side portions to form a pants-type diaper and a method for manufacturing the same.

Background

Diapers worn by infants and young children are known as pants-type disposable diapers in the past. A typical pants-type disposable diaper includes an absorbent body having a liquid absorbing function, and a cover sheet for supporting the absorbent body in the crotch of a wearer. The cover sheet is formed by joining the front body and the rear body at both left and right ends in advance, and thereby the disposable diaper is formed into a pants type. Therefore, the wearer can wear the pants-type disposable diaper by inserting both legs from the opening around the waist. Further, in the side seal portions, in order to join both end portions of the front body and the rear body with a moderate joining strength, the pants-type disposable diaper can be easily removed by the wearer by tearing the side seal portions.

The side seals as described above are generally formed by heat-welding the respective members of the thermoplastic sheet constituting the covering sheet of the diaper to each other by heat-sealing or ultrasonic sealing. For example, heat sealing is a process of introducing a plurality of thermoplastic sheets laminated between a pair of rollers consisting of an embossing roller having a joining pattern block engraved on one side and a flat anvil roller. And then, the thermoplastic sheet is heated and pressed by using the embossing roller and the anvil roller to dissolve the sheet. The ultrasonic sealing is a bonding technique in which a plurality of laminated thermoplastic sheets are introduced between an engraved bonding pattern block and an ultrasonic horn that transmits ultrasonic vibration, and the sheets are pressed while applying ultrasonic vibration to dissolve the sheets by frictional heat.

As described above, a technology of forming a pair of side edge seal portions on both left and right side portions of a disposable diaper by heat sealing or ultrasonic sealing is disclosed in patent document 1 or patent document 2.

Documents of the prior art

Patent document

Patent document 1 Japanese Kokai publication 2004-523374

Japanese patent application laid-open No. 2002-102283 of patent document 2

Disclosure of Invention

Problems to be solved by the invention

However, the cover sheets constituting the front and rear bodies of the disposable diaper are bonded only at the joint portions extending in the vertical direction, and are not bonded at the outer portions of the joint portions. That is, since the front cover sheet and the rear cover sheet are not bonded to each other at a portion located on the left-right outer side of the joint portion, the front cover sheet and the rear cover sheet may be loosened and loosened at the non-bonded portion, which causes a problem of poor appearance.

However, many elastic stretchable members for imparting stretchability to a cover sheet of a diaper are fixed. For example, the elastic members are sandwiched between a plurality of layers of sheet-like members at the waist or abdomen portions of the front and back bodies and fixed with a hot melt adhesive or the like. As a method of applying the hot melt adhesive, for example, the hot melt adhesive may be applied to a surface of a sheet member constituting a cover sheet, or may be applied directly to an elastic stretchable member. In addition to fixing the elastic stretchable member, a hot-melt adhesive may be applied to the cover sheet to adhere the front and rear cover sheets to each other. However, as described above, when the side seal portions are formed on the left and right side portions of the disposable diaper, a joining technique such as heat sealing or ultrasonic sealing may be used. The heat sealing or ultrasonic sealing is performed by heat welding thermoplastic sheets to each other. However, if the hot melt adhesive is present in the bonded portion of the thermoplastic sheets, the thermoplastic sheets to be bonded are not sufficiently heated by the heat used for dissolving the hot melt adhesive, and the bonding strength is unstable, and the adhesive property is exhibited in the bonded portion by the dissolved hot melt adhesive, and the relief pattern of the bonded portion is solidified in a disordered state and becomes hard. Therefore, if the joining of the side sealing portions is mentioned, it is preferable that the hot melt adhesive is not applied to the joining portions. Therefore, in the disposable diaper, it is preferable that the hot-melt adhesive is not applied or the elastic stretchable member is not fixed to a portion where the side seal portion is to be formed. For example, by intermittently applying a hot-melt adhesive for fixing the elastic stretchable member except for the portions where the side seal portions are formed, at least the side seal portions can be made free from the hot-melt adhesive or the elastic stretchable member. However, since the hot melt adhesive is intermittently applied, the areas where the hot melt adhesive is not present are formed on both the left and right side portions (side seal portions) of the disposable diaper, and the areas where the front body and the rear body are not bonded to each other (non-bonded areas) remain in the areas on both sides of the finished disposable diaper outward in the left and right direction from the bonded portions (main bonded areas) where the front body cover sheet and the rear body cover sheet are bonded to each other. Therefore, the left and right side edges of the disposable diaper have a problem that the front cover sheet and the rear cover sheet are not beautiful because they are not attached to each other.

On the other hand, in order to prevent the front cover sheet and the rear cover sheet from being separated at the left and right side portions, the joining portions are formed at positions close to the left and right side edges of the diaper. However, as described later, the pants-type diaper is obtained by stacking a plurality of continuous sheets, joining the continuous sheets at 2 pairs of joined portions, and cutting the joined portions in between. Therefore, if there is no space between the joint portions, the joint portions may not be cut at the time of cutting, and the joint portions may be cut. As a result, the degree of unevenness in the bonding strength of the bonding portion becomes large. Further, since a plurality of joint portions are exposed in the cut portion, the touch may be deteriorated. Therefore, it is not preferable that the joint portion (main joint region) for the purpose of joining the front cover sheet and the rear cover sheet is formed at the edge portions near the left and right sides of the diaper.

As described above, in the conventional art, it is difficult to achieve both an excellent appearance of the side seal portion of the pants-type disposable diaper and an excellent tactile sensation of the side seal portion. Therefore, there is a need for a technique for a side seal portion of a pants-type disposable diaper, which can prevent an unpleasant appearance such as a front cover sheet and a rear cover sheet from coming loose at both right and left side portions of the diaper, and can prevent the skin feel of both right and left side portions of the diaper from being impaired.

Means to solve the problems

Accordingly, the present inventors have made an effort to solve the above-mentioned problems of the prior art, and as a result, have found that the front body and the rear body of the disposable diaper are joined to each other at the main joining regions at the left and right side portions thereof, and that the front body covering sheet and the rear body covering sheet are prevented from being unfastened by forming the sub-joining regions having a weaker joining strength than the main joining regions at the left and right outer sides of the main joining regions, thereby improving the appearance of the pants-type disposable diaper and preventing the touch of the left and right side portions from being impaired. Therefore, the present inventors have devised a solution to the problems of the prior art based on the above knowledge, and have completed the present invention.

The present invention has the following composition, if specifically described.

The invention of claim 1 relates to a pant-type disposable diaper.

The pants-type disposable diaper of the present invention is divided into a front body 1 joined to the abdomen of a wearer, a rear body 2 joined to the back of the wearer, and a crotch portion 3 located between the front body 1 and the rear body 2. Further, the pants-type disposable diaper has a pair of side seal portions 4 formed by heat-sealing or ultrasonic-sealing the left and right side portions of the front body 1 and the left and right side portions of the rear body 2 in a state of being respectively corresponding to and overlapping each other.

Here, the pair of side sealing portions 4 includes a main joining region 40 extending in the vertical direction, and a sub joining region 50 located on the outer side of the main joining region 40 in the left-right direction and extending in the vertical direction.

The sub-joint region 50 is a region formed by arranging one or more rows of embossments in which a plurality of sub-embossments 51 are arranged at a vertical interval.

As described above, the pants-type disposable diaper of the present invention has the auxiliary join regions 50 formed on the left and right outer sides of the main join regions 40 for preventing the front and rear portions from coming loose, and the main join regions 40 are formed for joining the left and right side portions of the front and rear portions. Thus, the problem that the cover sheets of the front body and the rear body at the left and right side portions of the diaper are not beautiful when they are floated and released can be solved by providing the sub-joint regions 50. Further, the bonding strength of the sub bonding region 50 is weaker than that of the main bonding region 40. That is, the secondary joining regions 50 are not intended to join the both side portions of the front and back of the diaper, but are intended to prevent the cover sheet from coming loose at the both side portions of the diaper, and therefore, the joining strength thereof can be significantly weakened compared to the joining strength of the primary joining regions 40. Thus, even if the sub joint region 50 is provided, the touch feeling of the diaper is hardly affected, and as a result, the wearing feeling of the diaper can be improved.

In the present invention, the bonding strength of the sub bonding region 50 is preferably 50% or less compared to the bonding strength of the main bonding region 40.

With the above-described configuration, the bonding strength of the secondary bonding region 50 is set to be equal to or less than half of the bonding strength of the primary bonding region 40, whereby the touch and feel of the secondary bonding region 50 as a whole can be maintained soft. Further, by setting the bonding strength of the sub-bonded regions 50 low, it is possible to prevent the left and right side portions of the diaper bonded by the side seal portions 4 from becoming less likely to be broken when the disposable diaper is removed by the wearer.

In the pants-type disposable diaper of the present invention, the front body 1 and the rear body 2 are preferably joined at both left and right sides thereof only by heat welding using heat sealing or ultrasonic sealing without applying an adhesive to the main joining region 40 and the sub joining region 50. For example, in the main joining region 40 and the sub joining region 50, sheet members constituting both right and left side portions of the front body 1 and the back body 2 are preferably not joined by an adhesive, and the elastically stretchable member is preferably not fixed to the sheet members constituting both right and left side portions of the front body 1 and the back body 2 by an adhesive.

As described above, when an adhesive such as a hot melt adhesive is present in the portion where the primary joining region 40 and the secondary joining region 50 are expected to be formed, even if the primary joining region 40 and the secondary joining region 50 are formed by a thermal welding technique using heat sealing or ultrasonic sealing, the heat generated by the heat sealing or ultrasonic sealing is used to dissolve the hot melt adhesive. In this way, there are problems that the thermoplastic sheet to be joined cannot be sufficiently heated, the joining strength is unstable, the melted hot melt adhesive exhibits tackiness at the joined portion, and the relief pattern of the joined portion is solidified and hardened in a disordered state. Therefore, for joining the side sealing portions, it is preferable that the joining portion is not coated with the hot melt adhesive. However, if the hot melt adhesive is not applied to the side seal portions, there is a problem that the front cover sheet and the rear cover sheet float and turn over at both the right and left side portions of the diaper, which is not aesthetically pleasing. Therefore, in order to solve the above problems at the same time, in a preferred embodiment of the present invention, the hot melt adhesive is not applied to the portion where the side seal portion is to be formed, and the main joining region 40 and the sub joining region 50 are formed in the portion where the hot melt adhesive is not applied, so that the cover sheet of the front body and the cover sheet of the rear body are prevented from being separated from each other, and the both side portions of the disposable diaper are bonded with good appearance and good stability.

In the pants-type disposable diaper of the present invention, at least 2 or more of the plurality of sub-embossed portions 51 formed in the sub-joined region 50 preferably reach the side edges 4a on both the left and right sides of the front body 1 and the rear body 2.

With the above configuration, the plurality of sub-relief portions 51 reach the left and right side edges 4a of the front body 1 and the rear body 2, and thus the front cover sheet and the rear cover sheet can be more reliably prevented from coming apart.

In the pants-type disposable diaper of the present invention, the main fastening region 40, in which the main embossed portions 41 are arranged in a vertically spaced row, is preferably a region formed by arranging a plurality of main embossed portions. Similarly, the sub bonding region 50 is preferably a region formed by arranging a plurality of sub embossed portions 51 in a vertically aligned embossed row with a space therebetween. Here, the bonding strength of the sub bonding region 50 is preferably 30% or less than the bonding strength of the main bonding region 40.

With the above-described configuration, both the main bonded area 40 and the sub bonded area 50 are formed by a plurality of embossed rows provided at a distance in the left-right direction, and the bonding strength of the sub bonded area 50 is significantly weakened as compared with the bonding strength of the main bonded area 40, so that the front cover sheet and the rear cover sheet can be effectively prevented from being loosened and the diaper can be prevented from being damaged in its skin feel.

The primary joining region 40 is a joining portion for providing joining strength necessary for both side portions when worn, and the secondary joining region 50 is a joining portion for preventing the lateral outer sides of the primary joining region 40 from coming loose. Therefore, the bonding strength of the primary bonding region 40 and the secondary bonding region 50 is preferably greatly different from each other as described above. That is, if there is no great difference in the bonding strength between the main bonding region 40 and the sub bonding region 50, a large force is required to tear the side seal 4. This can cause pressure on the wearer and the tearing force can shake the wearer causing discomfort to the wearer.

Further, in the pants-type disposable diaper of the present invention, the main joint regions 40 are preferably provided so as to extend to the limit in the vertical direction at both left and right side portions of the pants-type disposable diaper. In contrast, the vertical length of the sub bonding region 50 is preferably shorter than the vertical length of the main bonding region 40. Further, the sub joint regions 50 are preferably arranged so as to be offset at positions not coinciding with the vertical end portions of the diaper. Here, the vertical length refers to the interval between the outer edges of the relief pattern located at the outermost portion.

In the position of the sub joint region 50 as described above, since the joint portions are not exposed at the upper end and the lower end of the diaper, it is possible to prevent the skin from contacting the hard joint portions, which may cause discomfort to the wearer. On the other hand, since the main joint region 40 must provide strength not to be torn around the abdomen or around the legs when the diaper is worn and when the diaper is used, it is preferable to set the length in the up-down direction of the diaper to the limit.

The invention of claim 2 relates to a method of manufacturing a pant-type disposable diaper. A pants-type disposable diaper has a front body 1 joined to the abdomen of a wearer, a rear body 2 joined to the abdomen of the wearer, and a crotch portion 3 located between the front body 1 and the rear body 2.

The manufacturing method of the present invention includes the following steps:

a step of obtaining a diaper continuous body in which a plurality of disposable diapers are connected in the right-left direction;

a step of folding back the diaper continuous body in the crotch part 3 and overlapping the front body 1 and the back body 2;

a joining step of heat-sealing or ultrasonic-sealing the side seal portions 4 for heat-welding the left and right side portions of the front body 1 and the left and right side portions of the rear body 2; and

a cutting step of cutting the diaper continuous body in the vertical direction at the positions corresponding to the left and right side edges 4a of the front body 1 and the back body 2 to obtain individual pants-type disposable diapers.

Here, the side seal portion 4 formed in the joining step includes a main joining region 40 extending in the vertical direction and a sub joining region 50 located on the outer side of the main joining region 40 in the left-right direction and extending in the vertical direction.

The sub-bonding region 50 is a region formed by arranging a plurality of sub-embossed portions 51 in a vertically spaced row, and the bonding strength of the sub-bonding region 50 is weaker than that of the main bonding region 40.

Next, in the cutting step, the diaper continuous body is cut in the vertical direction at the boundary positions of the 2 sub-joint regions 50.

According to the above-described process, the pants-type disposable diaper of the invention 1 can be continuously and efficiently manufactured.

Effects of the invention

The present invention can provide a pants-type disposable diaper in which side seals formed on both left and right side portions of the diaper have an excellent appearance and the side seals have an excellent tactile sensation.

Drawings

FIG. 1 is a perspective view showing the appearance of a disposable diaper of the present invention;

FIG. 2 is an exploded view showing a disposable diaper of the present invention;

FIG. 3 is a view showing an example of a bonding pattern in the side sealing part;

FIG. 4 is a view showing a bonding pattern in the side seal portion;

FIG. 4(a) is a cross-sectional view of the disposable diaper shown in Y1-Y1 in FIG. 2;

FIG. 4(b) is a cross-sectional view of the disposable diaper shown in Y2-Y2 in FIG. 2;

FIG. 4(c) is an enlarged plan view showing the side seal portions;

FIG. 5 is an enlarged view showing a bonding pattern included in a main bonding area of a side seal portion;

FIG. 6 is an enlarged comparative view showing the primary and secondary land areas included in the side seal portion;

FIG. 7 is a flow chart illustrating one embodiment of a method of manufacturing a disposable diaper of the present invention;

fig. 8 is another example of the bonding pattern in the side sealing portion, fig. 8(a) shows an example in which the sub-relief portion is arranged along a predetermined cutting line, and fig. 8(b) shows an example in which the sub-bonding region is formed by using a short linear sub-relief portion; and

fig. 9 is another example of the bonding pattern in the side sealing portion, fig. 9(a) is a modification of fig. 8(b), and fig. 9(b) is an example of a long linear sub-relief portion.

Detailed Description

Now, the best mode of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and modifications within the scope of the present invention will be apparent to those skilled in the art.

In the present specification, the term "vertical direction" refers to a vertical direction (a direction indicated by an arrow Y in fig. 1 and the like) when a waist opening is an upper end and a crotch portion is a lower end in a pants-type disposable diaper in which both end portions of a front body and a rear body are joined. The term "right-left direction" refers to the circumferential direction (the direction indicated by the arrow X in fig. 1 and the like) of the disposable diaper in which both ends of the front body and the rear body are joined.

In the present specification, "a to B" means "a to B inclusive".

(1, integral composition of disposable diaper)

The present invention is widely applicable to any diaper of the pants type disposable type. The pants-type disposable diaper refers to a disposable diaper in which both side portions of a front body and a back body are joined in advance. For example, the pants-type disposable diaper may have a structure in which an absorbent body is bridged between a front body outer cover and a rear body outer cover which are formed separately from each other. Further, the pants-type disposable diaper may be of a type in which an absorbent body is fixed to an outer cover integrally formed from a front body to a rear body with a crotch portion as a center, and the present invention will be specifically described below by taking a pants-type disposable diaper of a type in which a front body outer cover is provided separately from a rear body outer cover and an absorbent body is bridged between the outer covers as an example.

Fig. 1 is a perspective view showing an example of a disposable diaper 100 as seen from the front body side. Fig. 2 is an exploded view showing an example of the disposable diaper 100, and shows the disposable diaper 100 as seen from the skin-contact surface side. As shown in the exploded view of fig. 2, the disposable diaper 100 is divided into a front body 1 joined to the abdomen of the wearer, a rear body 2 joined to the back of the wearer, and a crotch portion 3 adjacent to the crotch of the wearer when worn. In the present embodiment, the disposable diaper 100 includes a front body outer cover 1a on the front body 1 and a rear body outer cover 2a on the rear body 2. The crotch portion 3 between the front body cover 1a and the back body cover 2a is bridged by an absorbent body main body 3 a. That is, in the present embodiment, the absorbent body main body 3a is fixed to the front body exterior body 1a at one end portion side in the longitudinal direction thereof, and is fixed to the rear body exterior body 2a at the other end portion side in the longitudinal direction thereof.

In the exploded state shown in fig. 2, the left and right end portions of the front body exterior body 1a and the rear body exterior body 2a are joined in a state of being superimposed on each other. A pair of left and right side sealing portions 4 are formed at the joint portion. In the pair of side seal portions 4, both end portions of the front body exterior body 1a and both end portions of the rear body exterior body 2a are joined to each other in a corresponding manner, and thus the state shown in fig. 1 is assembled from the exploded state shown in fig. 2. As shown in fig. 1, a waist opening 5 is formed by the upper end edge of the front body cover 1a and the upper end edge of the rear body cover 2 a. The front body exterior member 1a and the rear body exterior member 2a are joined at both ends thereof to the side seal portions 4, thereby forming foot peripheral openings 6 which are positioned around the feet of the wearer when worn. Therefore, the wearer can wear the disposable diaper 100 by inserting both legs through the waist opening 5 and inserting each leg through the leg opening 6.

As shown in fig. 1 and 2, the pair of side sealing portions 4 has a main joining region 40 and a sub joining region 50. The main joining regions 40 extend in the vertical direction to join the front body exterior member 1a and the rear body exterior member 2a, with the purpose of fixing both left and right side end portions of the front body exterior member 1a and the rear body exterior member 2 a. On the other hand, the sub joining region 50 is formed outward in the right and left direction from the main joining region 40. The sub-joint regions 50 are formed to substantially prevent the left and right end portions of the front outer body 1a and the rear outer body 2a from floating and separating, and extend in the vertical direction to lightly join the front outer body 1a and the rear outer body 2 a. That is, the bonding strength of the sub bonding region 50 is set to be at least weaker than the bonding strength of the main bonding region 40.

(2, front body cover and rear body cover)

Next, the composition of each part of the disposable diaper 100 will be described.

As shown in fig. 1 and 2, the front outer cover 1a and the back outer cover 2a hold the members of the absorbent body 3a positioned between the front outer cover 1a and the back outer cover 2a when the disposable diaper 100 is worn. The front body exterior member 1a is a member that contacts the wearer's abdomen when worn, and the back body exterior member 2a is a member that contacts the wearer's back when worn.

The front body exterior member 1a and the rear body exterior member 2a are joined to each other at both lateral end portions, and a pair of side seal portions 4 are formed at the joined portions. Fig. 3 shows an enlarged bonding pattern of the side seal portion 4. As shown in fig. 3, the side seal portions 4 have main joining regions 40 extending in the vertical direction from the upper end to the lower end at both left and right side portions of the front body exterior body 1a and the rear body exterior body 2a, and sub joining regions 50 joining both left and right side portions of the front body exterior body 1a and the rear body exterior body 2a at the outer sides in the left-right direction from the main joining regions 40. In the present embodiment, the primary joining region 40 and the secondary joining region 50 are each formed by a plurality of integrated embossed portions (primary embossed portion 41 and secondary embossed portion 51). The embossments (main embossments 41, sub embossments 51) referred to herein mean one joint. The primary bonding region 40 is a band-shaped region extending in the vertical direction from the innermost inner edge to the outermost outer edge of the plurality of primary embossed portions 41. Similarly, the sub-joint region 50 is a band-shaped region extending in the vertical direction from the innermost inner edge to the outermost outer edge of the plurality of sub-embossed portions 51. As shown in fig. 3, the primary joining region 40 and the secondary joining region 50 are each formed by arranging a plurality of primary embossed portions 41 and a plurality of secondary embossed portions 51 in a regular pattern. The details of the primary joining region 40 and the secondary joining region 50 will be described later.

Fig. 4(a) is a cross-sectional view of the disposable diaper in the exploded state shown in fig. 2, taken along the line Y1-Y1 in fig. 2, showing the disposable diaper in a cut state in the longitudinal direction. FIG. 4(b) is a cross-sectional view of the disposable diaper in the disassembled state shown in FIG. 2, taken along the line Y2-Y2 in FIG. 2, showing the disposable diaper in a cut state in the longitudinal direction. In addition, although various sheets are originally very thin, in fig. 4(a) or 4(b), for ease of understanding of the description, the sheets are conceptually drawn with a thickness.

The front body exterior body 1a and the back body exterior body 2a have an outer sheet 10 on the skin non-contact side and an inner sheet 12 on the skin contact side. The outer sheet 10 and the inner sheet 12 may be formed of, for example, soft fiber nonwoven fabric or plastic sheet. The fiber nonwoven fabric or the plastic sheet is bonded to each other by, for example, a hot melt adhesive. It is preferable that no hot melt adhesive be present at the positions where the primary joining region 40 and the secondary joining region 50 are expected to be formed to join the outer sheet 10 and the inner sheet 12. If the hot melt adhesive is provided at the portions where the primary bonding region 40 and the secondary bonding region 50 are expected to be formed, even if the primary bonding region 40 and the secondary bonding region 50 are intended to be formed by a thermal welding technique using heat sealing or ultrasonic sealing, the heat generated by the heat sealing or ultrasonic sealing becomes a heat for dissolving the hot melt adhesive. This has the disadvantage that the thermoplastic sheet to be joined cannot be sufficiently heated, the joining strength becomes unstable, the melted hot-melt adhesive exhibits tackiness at the joining portion, and the hot-melt adhesive is hardened by curing. Therefore, it is preferable that no hot melt adhesive is applied to the joint portion where the side seal portion 4 is formed.

Further, the plurality of waist stretch materials 20 are disposed in a stretched state along the waist peripheral end portions of the front body outer cover 1a and the rear body outer cover 2 a. A part of the plurality of waist stretch materials 20 is joined to the front body exterior member 1a and the rear body exterior member 2a in a stretched state, and is contracted to form a waist gather. Further, a knit-like worsted stretchable material 21 is disposed below the plurality of waist stretchable materials 20 (on the crotch side). The knit-like worsted stretchable material 21 is fixed in a stretched state between the outer sheet 10 and the inner sheet 12, and virtual wrinkles are formed around the abdomen of the disposable diaper by shrinking the knit-like worsted stretchable material 21.

As shown in fig. 4(a) and (b), the front body outer cover 1a and the back body outer cover 2a are provided with an outer sheet 10 on the outermost layer on the skin non-direct contact surface side. In the front outer cover 1a and the back outer cover 2a, the outer sheet 10 is folded back at the skin-contacting surface at the fold-back line 11a at the upper end edge to form a fold-back portion 11. The fold-back line 11a of the fold-back outer sheet 10 corresponds to the upper end portions of the front body outer cover 1a and the back body outer cover 2a, and serves as an opening edge of the waist opening 5 when the disposable diaper is completely assembled. The reverse fold portion 11 of the outer sheet 10 extends in the vertical direction, for example, by a length short of the position where the mock worsted stretch fabric 21 is disposed.

As shown in fig. 4(a) and (b), in the front outer cover 1a and the rear outer cover 2a, a plurality of waist stretch panels 20 and a plurality of mock worsted stretch panels 21 are arranged in a stretched state in a direction along the reverse folding line 11a on the outer sheet 10. The number of the waist stretch panels 20 may be 2 or more, and may be, for example, 2 to 15, 4 to 12, or 6 to 9. A plurality of worsted stretch panels 21 are provided on the outer sheet 10 below the waist stretch panel 20. The number of the stretch materials 21 for the knit-like worsted fabric may be, for example, 10 to 30, 15 to 25, or 18 to 20. As shown in fig. 4(a) and (b), the waist stretch materials 20 and the knit-like worsted stretch materials 21 are arranged approximately flat at a fixed interval in the longitudinal direction of the disposable diaper. As shown in the exploded view of fig. 2, the plurality of waist stretch panels 20 and the plurality of worsted stretch panels 21 are preferably arranged in the stretched state so as to extend to the side seal portions 4 located at both left and right end portions of the front body exterior body 1a and the rear body exterior body 2 a. The waist elastic members 20 and the worsted elastic members 21 may be fixed by applying or spraying an adhesive having high fluidity, such as a hot melt adhesive. However, it is preferable that the waist elastic members 20 and the knit-like woollen elastic members 21 are not present at the portions joined by the side seal parts 4. This is because, if the waist stretch material 20 or the knit-like worsted stretch material 21 is present in the side seal portions 4, when the front outer cover 1a and the left and right side portions of the rear outer cover 2a are joined to each other in the side seal portions 4, various elastic stretch members are dissolved by heat generated by heat sealing or ultrasonic sealing, and the joining of the left and right side portions of the front outer cover 1a and the rear outer cover 2a is unstable.

As shown in fig. 4(a) and (b), the cushion-forming sheet 13 is preferably disposed between the folded-back portion 11 formed by folding back the outer sheet 10 and the plurality of waist stretch members 20. The cushion-forming sheet 13 is a sheet arranged to improve the cushioning properties and flexibility of the waist gathers. The cushion-forming sheet 13 is preferably formed of a nonwoven fabric. The nonwoven fabric of the cushion-forming sheet 13 may be a hydrophilic nonwoven fabric or a water repellent nonwoven fabric. The cushion-forming sheet 13 is preferably intermittently joined to the inward-facing surface of the reverse fold 11 in the direction along the reverse fold line 11a on the "skin non-contact surface side" side on which the skin is directly contacted. The term "intermittently joined" means that a joined portion and a non-joined portion are continuously formed at a certain interval. By intermittently joining the cushion-forming sheet 13 and the reverse fold portion 11 along the reverse fold line 11a, when the waist stretch material 20 or the mock worsted stretch material 21 contracts, a space is created between the cushion-forming sheet 13 and the reverse fold portion 11, and the cushion property and flexibility of the waist gather can be improved by the space. The cushion-forming sheet 13 is formed so as to extend in the vertical direction of the diaper, the upper end side of the cushion-forming sheet 13 extends to the position of the reverse fold line 11a of the outer sheet 10, and a part of the lower end side of the cushion-forming sheet 13 overlaps the skin-directly contacting side of the inner sheet 12. However, the cushion-forming sheet 13 does not have a length reaching the lower end of the inner sheet 12.

Further, Japanese patent application laid-open No. 2011-254996 discloses a disposable diaper having the above-described cushion-forming sheet 13.

As shown in fig. 4(a) and (b), the inner sheet 12 is positioned on the skin-direct contact surface side of the outer sheet 10. The inner sheet 12 is fixed to the outer sheet 10 by sandwiching a part of the plurality of waist elastic members 20 and the plurality of mock worsted elastic members 21. The inner sheet 12 is formed to have a length reaching the lower edge of the outer sheet 10, although not reaching the upper edge of the outer sheet 10. The inner sheet 12 may be overlapped with the cushion forming sheet 13 at a part of the upper side. Further, the inner sheet 12 may be partially overlapped with the cushion forming sheet 13 and the folded portion 11 of the outer sheet 10 on the upper side.

As described above, the front outer cover 1a and the rear outer cover 2a are formed by overlapping a plurality of sheets. For example, in the present embodiment, the outer sheet 10, the cushion-forming sheet 13, and the folded-back portion 11 of the outer sheet 10 are sequentially stacked 3 on the 1 st laminated portion 71 at the uppermost portion of the front body cover 1a and the rear body cover 2a from the skin non-direct contact surface side. In the 2 nd laminated portion 72 located below the 1 st laminated portion 71, the outer sheet 10, the inner sheet 12, the cushion-forming sheet 13, and the folded back portion 11 of the outer sheet 10 are sequentially laminated 4 from the skin non-direct contact surface side. The 3 rd laminated part 73 located below the 2 nd laminated part 72 is formed by laminating the outer sheet 10, the inner sheet 12, and the cushion forming sheet 13 in this order 3 from the skin non-direct contact surface side. Further, the outer sheet 10 and the inner sheet 12 are stacked in order 2 from the skin non-direct contact surface side on the 4 th laminated portion 74 located at the lowermost part of the front body exterior body 1a and the rear body exterior body 2 a. As described above, the number of sheets to be stacked on the front outer cover 1a and the rear outer cover 2a may be different at the side seal portions 4 depending on the portions.

As described above, the front outer cover 1a and the rear outer cover 2a, which are formed by stacking a plurality of sheets, are joined to each other at the pair of side seal portions 4 located at the left and right end portions. That is, the left and right side portions of the front outer cover 1a and the rear outer cover 2a are joined in an overlapping state, and a pair of side seal portions 4 are formed on both side portions of the front outer cover 1a and the rear outer cover 2 a. The front outer cover 1a and the back outer cover 2a are preferably joined by, for example, heat sealing or ultrasonic sealing.

(2-1, Main joining region)

Here, the main joining region 40 included in the side seal portion 4 will be described in detail.

Fig. 4(c) is an enlarged plan view showing one end of the front outer body 1a and the rear outer body 2a joined to the side seal portions 4. The sectional view of fig. 4(a), the sectional view of fig. 4(b), and the plan view of fig. 4(c) are all shown with the vertical dimensions being the same. In particular, fig. 4(c) shows an embodiment of a bonding pattern in the main bonding region 40 of the side seal part 4. The bonding pattern of the main bonding region 40 is not limited to that shown in fig. 4 (c).

As shown in fig. 4(c), the main joined region 40 extending straight in the vertical direction of the diaper is divided into 2 regions, i.e., an upper joined region 40a located above and a lower joined region 40b located below. In fig. 4(c), the upper bonding region 40a and the lower bonding region 40b are shown as being laterally separated by a dotted line. The upper bonding region 40a and the lower bonding region 40b need not bisect the main bonding region 40, and may be formed such that the upper bonding region 40a is longer than the lower bonding region 40b as shown in fig. 4(c), or vice versa. Referring to fig. 4(a), 4(b), and 4(c), the number of stacked bonding sheets in the upper bonding region 40a and the lower bonding region 40b is different. That is, the number of stacked sheets in the upper joining region 40a is larger than that in the lower joining region 40 b. For example, in the embodiment shown in fig. 4, the upper joining region 40a joins the front body exterior member 1a and the rear body exterior member 2a at the 1 st laminated part 72, the 2 nd laminated part 72, and the 3 rd laminated part 73. Therefore, in the upper joining region 40a, 6 or 8 sheets are overlapped and joined, when the total number of sheets constituting the front outer cover 1a and the rear outer cover 2a is added. On the other hand, in the embodiment shown in fig. 4, the lower joining region 40b joins the front body exterior body 1a and the rear body exterior body 2a at the fourth laminated portion 74. Therefore, in the lower joining region 40b, if the total number of sheets constituting the front body outer cover 1a and the rear body outer cover 2a is added, 4 sheets are joined in an overlapping manner.

However, the number of sheets joined to the upper joining region 40a and the lower joining region 40b in the main joining region 40 is not limited to the above-described configuration. That is, the upper joining region 40a may be located above the lower joining region 40b and the number of sheets equal to or greater than the number of sheets in the lower joining region 40b may be overlapped and joined, and the lower joining region 40b may be located below the upper joining region 40a and the number of sheets equal to or less than the number of sheets in the upper joining region 40a may be overlapped and joined.

As shown in fig. 4(c), the upper bonding region 40a is a region where a plurality of upper embossed portions 41a are formed, and the lower bonding region 40b is a region where a plurality of lower embossed portions 41b are formed. In the upper joining region 40a, a plurality of upper embossed portions 41a are formed in a plurality of rows along the diaper vertical direction. As shown in fig. 4(c), the upper embossed portion 41a is formed in 3 rows. Among the plurality of rows of the upper embossed portion 41a, the distance from the left end row to the right end row is the width of the upper bonding region 40 a. Similarly, in the lower joining region 40b, a plurality of lower embossed portions 41b are formed in a plurality of rows along the diaper vertical direction. As shown in fig. 4(c), the lower embossed portion 41b is formed in 3 rows. Among the plurality of rows of the lower embossed portion 41b, the distance from the left end row to the right end row is the width of the lower bonding region 40 b. The rows of the upper embossed portions 41a and the lower embossed portions 41b forming the upper bonding region 40a and the lower bonding region 40b are preferably a plurality of rows, and may be, for example, 4 rows to 10 rows. The number of rows of the upper embossed portions 41a may be different from the number of rows of the lower embossed portions 41 b.

Here, as shown in fig. 4(c), the width B1 of the upper and lower joining regions 40B in the lateral direction of the diaper is wider than the width Bu of the upper joining region 40a, and "Bl > Bu" is formed. For example, the width Bl of the lower bonding region 40b is preferably 105% to 150%, 110% to 145%, 115% to 140%, or 120% to 135% with respect to the width Bu of the upper bonding region 40 a. In particular, the lower joined region 40b is preferably wider in both the left and right directions of the diaper than the upper joined region 40 a. Specifically, when the width Bu of the upper joining region 40a is, for example, 2mm to 20mm, 4mm to 15mm, or 5mm to 10mm, the width Bl of the lower joining region 40b is preferably 3mm to 30mm, 5mm to 20mm, or 6mm to 15 mm. In this way, by making the width Bl of the lower joining region 40b wider than the width Bu of the upper joining region 40a, the joining strength of the lower joining region 40b having a small number of joined sheets can be improved, and a balance can be achieved with the joining strength of the upper joining region 40a having a large number of joined sheets. Therefore, the hardness of the upper joining region 40a and the lower joining region 40b is made uniform, and as a result, the overall feel of the side seal 4 (particularly, the main joining region 40) is improved. Further, since the number of the joined pieces of the lower joined region 40b is small, the joined portion may be easily peeled off when the diaper is worn, but the width of the lower joined region 40b is increased to improve the adhesion strength, so that the peeling off when the diaper is worn can be prevented. Furthermore, since the width of the lower joining region 40b is increased, the adhesive strength can be improved without increasing the area of the lower embossed portion 41b itself, and therefore, the side seal portions 4 can be easily torn when the diaper is discarded after being wetted or soiled.

The bonding pattern of the primary bonding area 40 is described in further detail.

Fig. 5 is a further enlarged view showing a frame of a broken line shown in fig. 4 (c). Fig. 5 shows the arrangement relationship between the plurality of upper embossed portions 41a and the plurality of lower embossed portions 41 b. As shown in fig. 4, the upper relief portion 41a and the lower relief portion 41b are formed in 3 rows, and the intermediate rows are located on the same straight line. On the other hand, the left and right end rows of the lower embossed portion 41b are formed at positions extending outward in the lateral direction of the diaper than the left and right end rows of the upper embossed portion 41 a. Thus, the width B1 of the lower joining region 40B is wider than the width of the upper joining region 40 a.

As shown in fig. 5, each of the upper embossed portions 41a and each of the lower embossed portions 41b is preferably formed in a short line shape extending in the lateral direction of the diaper. The "short linear" upper relief portion 41a means that at least the length Lu in the left-right direction of the upper relief portion 41a is longer than the width Wu in the up-down direction of the upper relief portion 41a, and the length Lu has a value equal to or less than half of the value of the width Bu of the upper bonding region 40 a. Similarly, the lower relief portion 41b in the "short-line shape" means that at least the length Ll in the left-right direction of the lower relief portion 41b is longer than the width Wl in the up-down direction of the lower relief portion 41b, and the length Ll has a value equal to or less than half of the value of the width Bl of the lower bonding region 40 b. By forming the upper embossed portion 41a and the lower embossed portion 41b into a short line shape in this manner, the side seal portions 4 (particularly, the main joint regions 40) can be easily torn when the diaper is wet or soiled for disposal. That is, since the upper embossed portion 41a and the lower embossed portion 41b extend in the lateral direction of the diaper, the force at the time of tearing the diaper can be guided to the outside of the diaper. Therefore, by making the upper relief portion 41a and the lower relief portion 41b in a short line shape, the wearer can tear the diaper at one time and can easily tear the side seal portions 4.

The bonding area formed by each upper relief portion 41a and each lower relief portion 41b is preferably the same. In particular, it is preferable that the length Lu of the upper relief portion 41a is the same as the length Ll of the lower relief portion 41b, and the width Wu of the upper relief portion 41a is the same as the width W1 of the lower relief portion 41 b. For example, in the form shown in FIG. 5, the length Lu of the upper relief portion 41a and the length Ll of the lower relief portion 41b are preferably 0.5mm to 10mm, 1mm to 5mm, or 1.5mm to 3mm, respectively. The width Wu of the upper embossed portion 41a and the width Wl of the lower embossed portion 41b are preferably 0.2mm to 5mm, or 0.4mm to 3mm, respectively. In the present embodiment, as described above, the bonding strength of the lower bonding region 40b can be ensured by increasing the width Bl of the lower bonding region 40 b. Therefore, even when the bonding area of the lower embossed portion 41b forming the lower bonding region 40b is made the same as the bonding area of the upper embossed portion 41a forming the upper bonding region 40a, the bonding strength of the lower bonding region 40b can be ensured. Further, by making the bonding area of the lower relief portion 41b the same as the bonding area of the upper relief portion 41a, the upper bonding region 40a and the lower bonding region 40b can be easily torn by a continuous operation when urine is wet or when urine is discarded due to dirt.

In fig. 5, a symbol Su indicates a distance in the left-right direction between adjacent rows of the upper embossed portions 41a in the upper bonding region 40 a. As shown in fig. 5, the intervals Su in the left-right direction of the rows of adjacent upper embossed portions 41a are preferably all equal. In particular, the interval Su in the left-right direction between adjacent rows of the upper embossed portions 41a is preferably equal to the length Lu of the upper embossed portions 41a (Su ═ Lu).

Note that reference numeral S1 denotes the interval between adjacent rows of lower embossed portions 41b in the lower bonding region 40b in the left-right direction. As shown in fig. 5, the intervals S1 in the left-right direction of the rows of adjacent lower embossed portions 41b are preferably all equal.

When the interval Su between the rows of the upper embossed portions 41a is compared with the interval S1 between the rows of the lower embossed portions 41b, the value of the interval S1 is preferably larger than the value of the interval Su (S1 > Su). For example, the value of the interval S1 between the rows of the lower relief part 41b is 110% to 200%, 120% to 180%, or 130% to 160%, preferably 140% to 150%, with respect to the value of the interval Su between the rows of the upper relief part 41 a. As described above, in the present invention, by securing the interval S1 between the rows of the lower embossed portions 41B to be wider than the interval Su between the rows of the upper embossed portions 41a, the width B1 of the lower bonding region 40B can be made wider than the width Bu of the upper bonding region 40 a.

As shown in fig. 5, the width Bl of the lower bonding region 40b is made wider than the width Bu of the upper bonding region 40a, and a plurality of lower bonding regions 40b in the lower bonding region 40b located at the outermost row in the left-right direction form a protruding portion O (see the figure) protruding outward in the left-right direction from the width of the upper bonding region 40 a. In fig. 5, the projecting portion O is indicated by oblique lines. The protruding portions O are preferably formed in the lower bonding regions 40b located in the outermost rows in the left-right direction, respectively. For example, the length of the projecting part O in the lateral direction is preferably 0.1mm to 1mm, 0.3mm to 0.8mm, or 0.5mm to 0.6 mm.

In fig. 5, reference symbol Pu indicates the vertical intervals between the plurality of upper embossed portions 41a in a certain row. As shown in fig. 5, the upper embossed portion 41a preferably has the same vertical intervals Pu.

Note that, the symbol Pl indicates the vertical intervals of the plurality of lower embossed portions 41b in a certain row. As shown in fig. 5, the intervals Pl in the up-down direction of the lower embossed portion 41b are preferably all equal.

When the vertical interval Pu of the upper embossed portion 41a is compared with the vertical interval Pl of the lower embossed portion 41b, the value of the interval Pl is preferably smaller than the value of the interval Pu (Pu > Pl). For example, the value of the vertical interval Pl of the lower relief portion 41b is 50% to 95%, 55% to 90%, or 60% to 85%, preferably 65% to 80% of the value of the vertical interval Pu of the upper relief portion 41 a. In this way, since the lower embossed section 41b has a smaller vertical interval Pl than the upper embossed section 41a has, the bonding strength of the lower bonding region 40b with a small number of bonding sheets can be increased, and the bonding strength of the upper bonding region 40a with a large number of bonding sheets can be balanced. Therefore, the upper joining region 40a and the lower joining region 40b can be made uniform in hardness, and as a result, the side seal 4 as a whole can be made good in touch.

As shown in fig. 5, in the upper joining region 40a, the positions of the rows of adjacent upper embossed portions 41a are preferably shifted from each other in the vertical direction of the diaper. In fig. 5, the reference character Du indicates the distance by which the rows of the upper embossed portions 41a located at the left and right ends are shifted from the rows of the upper embossed portions 41a located at the center. For example, the rows of the upper embossed portions 41a are preferably shifted by a distance Du about half of the vertical interval Pu between the upper embossed portions 41a in a certain row.

Similarly, in the lower joining region 40b, the rows of the adjacent lower embossed portions 41b are preferably shifted in position from each other in the vertical direction of the diaper. In fig. 5, symbol Dl indicates a distance by which the rows of the lower embossed portions 41b located at the left and right ends are shifted from the rows of the lower embossed portions 41b located at the center. For example, the offset distance Dl of the rows of the lower embossed portions 41b is preferably about half of the vertical interval Pl of the plurality of lower embossed portions 41b in a certain row.

As described above, the bonding pattern in the primary bonding region 40 is exemplified by a pattern in which a plurality of primary embossed portions 41 are arranged at intervals in the vertical direction to form a plurality of rows, and the plurality of rows are arranged at intervals in the horizontal direction. However, the bonding pattern in the primary bonding region 40 is not limited to the above embodiment. For example, the bonding pattern in the main bonding region 40 may be a straight line extending in the up-down direction. The main embossed portion 41 forming the main joint region 40 may have a longitudinal shape parallel to the side end edges of the diaper. The main embossed portion 41 may be inclined at an angle of about 1 to 45 degrees, or about 2 to 30 degrees with respect to the side edge of the diaper. As described above, since the linear load can be increased by inclining the main relief portion 41, the bonding strength can be maintained, which is advantageous for stabilizing the bonding.

(2-2, sub junction region)

Next, the sub-joint region 50 included in the side seal part 4 will be described in detail.

Fig. 6 is an enlarged view showing the inside of a dashed frame shown in fig. 3. That is, the enlarged view shown in fig. 6 shows the upper portion of the primary joining region 40 and the upper portion of the secondary joining region 50.

As shown in fig. 6, the side seal 4 includes a primary joining region 40 and a secondary joining region 50. In the present embodiment, the main bonding region 40 is a band-shaped region extending in the vertical direction in which the plurality of main embossed portions 41 are arranged at intervals in the vertical direction and the horizontal direction, as described above. As shown in fig. 6, a margin S exists between the outer edge of the main joining region 40 and the left and right side edges 4a of the front body cover and the rear body cover. By providing the margin S between the main joining region 40 and the edge 4a in this manner, the main joining region 40 having a hard skin feel can be prevented from being exposed from the edge 4a and from directly contacting the skin of the wearer. Further, in general, a pants-type diaper is obtained by stacking a plurality of continuous sheets, joining the continuous sheets by 2 pairs of main joining regions 40, and cutting the joined sheets therebetween. Therefore, if there is no space between the main joint regions 40, the main joint regions 40 cannot be cut during cutting, and the main joint regions 40 may be cut. As a result, the degree of unevenness in the bonding strength of the main bonding region 40 becomes large. Here, as described above, by providing the margin S between the main joining region 40 and the edge 4a, it is possible to more reliably cut the continuous sheet between the pair of 2 main joining regions 40. From this viewpoint, the length of the margin S in the lateral direction is preferably set to be at least about 3mm to 20mm or about 5mm to 10 mm. However, if the margin S exists between the main joint region 40 and the edge 4a, the left and right end portions of the front body cover and the rear body cover may be loosened by rattling, and the appearance of the entire diaper may be deteriorated. Therefore, in the present invention, the auxiliary joining regions 50 are formed in the margins S existing between the main joining regions 40 and the side edges 4a, and the left and right end portions of the front body outer covering and the rear body outer covering are prevented from coming loose by lightly joining the margins S to such an extent that the tactile sensation of the diaper is not impaired.

The purpose of the joining in the sub-joining region 50 is to fix the left and right end portions of the front body exterior body and the back body exterior body without peeling off when worn, and to gently join the left and right end portions of the front body exterior body and the back body exterior body to each other to such an extent that they do not come loose. Therefore, the bonding strength of the sub bonding region 50 is set lower than the bonding strength of the main bonding region 40. For example, when the bonding strength of the main bonding region 40 is 100%, the bonding strength of the sub bonding region 50 is preferably 50% or less, more preferably 30% or less, and further preferably 15% or less. For example, the bonding strength of the secondary bonding region 50 may be 1% to 50%, 1% to 30%, or 1% to 15% as compared to the bonding strength of the primary bonding region 40.

The pants-type disposable diaper is designed such that one or both of the left and right side portions can be pulled open when the diaper is removed. To reproduce this operation, the "joint strength" is obtained by stretching the main joint region 40 and the sub-joint region 50 in a direction of 180 degrees from the inside of the diaper using a tensile strength tester, and the maximum value of the strength is used as the joint strength.

That is, in the present patent specification, the "bonding strength" is a tensile strength measured by the method described below.

First, portions including the main bonding area 40 and the sub bonding area 50 to be measured for the bonding strength are cut into predetermined shapes (left-right direction: 25mm × up-down direction: 30mm) to obtain a main bonding area test piece and a sub bonding area test piece. Next, the main bonding area test piece facility was set in a tensile strength tester (trade name: Styrolavo V1-B, manufactured by Toyo Seiki Seisaku-sho Co., Ltd.). The main bonding area test piece is set by spreading the main bonding area test piece right and left with the main bonding area 40 in the middle, and clamping and fixing the spread both ends with the clamping members from the upper and lower sides. Here, the distance between the left and right clips was 20 mm. The tensile tester is operated in this state, and the main joint region test piece is stretched in the left-right direction, whereby the tensile strength of the main joint region test piece is measured. Here, the tensile rate was 200 mm/min, and the measurement was terminated when the test piece of the primary bonding area was broken. Then, the maximum tensile strength was confirmed from the measured measurement chart. The maximum tensile strength is referred to as "joint strength" in the present specification. After the joint portion of the primary joining region 40 is torn off in advance by the secondary joining region 50 as in the region S2 in fig. 6, the measurement of the "joining strength" which is the same as the joining strength of the primary joining region 40 can be performed.

Specifically, the bonding strength of the main bonding region 40 is preferably 5.0N/25mm or more. For example, the bonding strength of the main bonding region 40 is preferably 5.0N/25mm to 30.0N/25 mm. If the bonding strength of the main bonding region 40 is less than 5.0N/25mm, the bonding strength is too low, and when the diaper is worn and the diaper is pulled up while holding the side edge of the diaper, the main bonding region 40 may peel off and tear the entire diaper. On the other hand, if the bonding strength of the primary bonding region 40 exceeds 30.0N/25mm, the bonded portion may touch the skin and feel pain. Further, although the side edge portions of the pants-type disposable diaper must be torn in order to make the diaper easily detachable from the wearer, if the main joining region 40 has a joining strength exceeding 30.0N/25mm, the side edge portions may not be easily torn.

On the other hand, the bonding strength of the sub bonding region 50 is preferably 50% or less, 30% or less, or 15% or less with respect to the bonding strength of the main bonding region 40. For example, the bonding strength of the sub bonding region 50 is preferably 0.75N/25mm to 15.0N/25 mm. If the bonding strength of the sub-bonding region 50 is lower than 0.75N/25mm, the bonding strength is too low, and the sub-bonding region 50 is likely to be peeled off by the movement of the wearer, and it is meaningless to provide the sub-bonding region 50. On the other hand, if the joining strength of the sub joining region 50 exceeds 15.0N/25mm, the total joining width of the main joining region 40 and the sub joining region 50 becomes long, and it is inconvenient to apply a force when tearing. Further, if the joining strength of the sub joining region 50 exceeds 15.0N/25mm, the skin touch of the sub joining region 50 becomes hard, and there is a possibility that pain may occur when the skin touches the wearer.

As described above, there may be various methods of setting the bonding strength of the sub bonding region 50 weaker than the bonding strength of the main bonding region 40.

To set the bonding strength of the sub-bonding region 50 to be weak, for example, (a) the bonding area of the sub-bonding region 50 is made smaller than the bonding area of the main bonding region 40, (B) the lengths of the plurality of sub-embossed portions 51 arranged in the vertical direction of the sub-bonding region 50 in the vertical direction are made shorter than the length of the main bonding region 40 in total, and (C) the depth of each sub-embossed portion 51 of the sub-bonding region 50 is made shallower than the depth of each main embossed portion 41 of the main bonding region 40. Hereinafter, an example of a method of weakening the bonding strength of the sub-bonding region 50 will be described, but the sub-bonding region 50 of the present invention is not limited to this.

In the above (a), the joint area of the sub joint region 50 may be made smaller than the joint area of the main joint region 40 in order to set the joint strength of the sub joint region 50 weak. That is, even if the areas of the sub-embossed portions 51 provided in the sub-bonding regions 50 are the same as the areas of the main embossed portions 41 provided in the main bonding regions 40, the bonding strength of the sub-bonding regions 50 can be weakened by making the vertical intervals or the horizontal intervals of the embossed patterns of the sub-bonding regions 50 wider than the embossed patterns of the main bonding regions 40.

For example, in fig. 6, reference numeral Ps denotes the vertical intervals between a plurality of sub-relief sections 51 in a certain row. As shown in fig. 6, the vertical interval Ps between the sub-relief portions 51 is preferably wider than the vertical interval Pu between the main relief portions 41 (upper relief portions 41 a). For example, the vertical interval Ps between the sub-relief sections 51 is preferably 200% to 1000%, or 300% to 600% of the vertical interval Pu between the main relief sections 41. In fig. 6, reference numeral Ds denotes a distance in which the sub-relief portions 51 positioned in a certain row are vertically displaced from the sub-relief portions 51 positioned in the adjacent row. In this way, when the rows of the sub-embossments 51 are offset, the offset distance Ds is preferably larger than the vertical interval Pu between the main embossments 41. For example, the distance Ds is preferably 150% to 500%, or 200% to 300%, relative to the interval Pu.

In fig. 6, Gs represents the interval between the two sub-embossments 51 in the left-right direction. As shown in fig. 6, the left-right direction interval Gs of the rows of the sub-emboss portions 51 is preferably wider than the left-right direction interval Gs of the rows of the main emboss portions 41. For example, the left-right direction interval Gs of the rows of the sub-emboss portions 51 is preferably 120% to 500%, or 150% to 300% with respect to the left-right direction interval Gs of the rows of the main emboss portions 41. In this way, by making the interval in the vertical direction or the interval in the horizontal direction of the relief pattern in the sub bonding region 50 wider than the relief pattern in the main bonding region 40, the bonding area of the sub bonding region 50 can be made smaller than the bonding area of the main bonding region 40.

Specifically, the joint area ratio of the sub joint region 50 is preferably smaller than that of the main joint region 40. The joint area ratio of the sub-joint region 50 referred to herein is a ratio of the total area of the sub-relief portions 51 to the entire area of the sub-joint region 50. Similarly, the bonding area ratio of the primary bonding region 40 is a ratio of the total area of the plurality of primary embossed portions 41 to the entire area of the primary bonding region 40. The total area of the primary bonding region 40 and the secondary bonding region 50 can be determined by forming a band-shaped region extending in the vertical direction from the innermost inner edge to the outermost outer edge of each embossed portion as a width. The total area of the plurality of main embossed portions 41 and the total area of the plurality of sub embossed portions 51 can be obtained by multiplying the area of each embossed portion by the number of embossed portions of the main joining region 40 or the sub joining region 50. Thus, the bonding area ratio of the secondary bonding region 50 calculated is preferably 1% to 50%, more preferably 1% to 30%, and even more preferably 1% to 15% with respect to the bonding area ratio of the primary bonding region 40. Further, the area of one sub-relief portion 51 is preferably about 50% to 200%, more preferably 70% to 150%, relative to the area of one main relief portion 41.

Further, as shown in FIG. 6, the width Bs of the sub-bonding region 50 is preferably narrower than the width Bu of the main bonding region 40 (upper bonding region 40 a). The width Bs of the secondary joining region 50 is preferably 40% to 95%, or 50% to 70%, relative to the width Bu of the primary joining region 40 (upper joining region 40 a).

In the above (B), in order to make the bonding strength in the bonding region 50 weak, the total length in the vertical direction of the plurality of sub-embossed portions 51 arranged in the vertical direction in the sub-bonding region 50 may be made shorter than that in the main bonding region 40. That is, in the present specification, since (the joint strength) is defined as a peak of the tensile strength when the main joint region 40 and the sub-joint region 50 are spread and stretched 180 degrees from the inside of the diaper as described above, the joint strength can be said to be strong if the total length in the vertical direction of the plurality of embossed portions arranged in the vertical direction is long, and the joint strength can be said to be weak if the total length is short. The term "total length of the embossed portions arranged in the vertical direction" as used herein refers to the total length of the embossed portions in the vertical direction on a virtual line drawn in the vertical direction parallel to the side of the disposable diaper. When the upper and lower height sides of each embossed portion are not parallel to the imaginary line, the length of each embossed portion on the imaginary line is a length that intersects the embossed portion in the up-down direction. For example, the total length in the vertical direction of the plurality of sub-embossed portions 51 arranged in the vertical direction in the sub-bonding region 50 is preferably 1% to 50%, 1% to 30%, or 1% to 15% of the total length in the vertical direction of the plurality of main embossed portions 41 arranged in the vertical direction in the main bonding region 40.

In the above (C), in order to set the bonding strength of the sub-bonding region 50 to be weak, the depth of each sub-relief portion 51 in the sub-bonding region 50 may be set to be shallower than the depth of each main relief portion 41 in the main bonding region 40. When the side seal 4 is formed by heat sealing or ultrasonic sealing, the pattern block used for heat sealing or ultrasonic sealing is processed to have a substantially same height as that of the pattern block by barrel polishing, and the surface having the same height is processed to have a curved surface like that of a cylindrical surface. Therefore, the relief pattern arranged on the pattern block temporarily becomes equal in height. Then, after the relief pattern is processed to have the same height, the pattern blocks of the sub relief portions 51 forming the sub bonding region 50 may be further polished to have a lower pattern block height. For example, the height of the pattern block forming the sub-relief portion 51 is preferably lower by 3 μm or more than the height of the pattern block forming the main relief portion 41. For example, the height of the pattern block forming the sub-relief 51 is preferably lower by about 3 μm to 100 μm, or about 5 μm to 50 μm than the height of the pattern block forming the main relief 41. The height of the pattern block forming the sub-relief portion 51 may be gradually increased toward the pattern block forming the main relief portion 41. Thus, the depth of each sub-relief 51 in the bonding region 50 formed by the side seal 4 can be made shallower than the depth of each main relief 41 in the main bonding region 40. When the depth of each sub relief portion 51 is made shallow, the bonding strength of the sub bonding region 50 is weakened as a result. Further, by adjusting the depth of each sub-relief portion 51, the relief pattern of the main bonding region 40 and the relief pattern of the sub-bonding region 50 may be the same pattern as long as the bonding strength of the sub-bonding region 50 can be set to an appropriate range.

In the above description, the relief pattern of the sub bonding region 50 is described in comparison with the relief pattern of the main bonding region 40, but the relief pattern of the sub bonding region 50 and the relief pattern of the main bonding region 40 may have different bonding strengths depending on the regions. For example, the joint area ratio between the relief pattern of the sub-joint region 50 and the relief pattern of the main joint region 40, the vertical interval of the relief portion, the horizontal interval, and the like may be different depending on the region. In the case where the sub bonding region 50 and the main bonding region 40 have a plurality of bonding area ratios, vertical intervals of embossed portions, horizontal intervals, and the like, the sub bonding region 50 and the main bonding region 40 may be compared by cutting predetermined portions adjacent to each other in the horizontal direction. For example, as described in the method of measuring the "bonding strength", the comparison between the sub-bonding region 50 and the main bonding region 40 may be performed by cutting a predetermined portion (left-right direction: 25 mm. times. up-down direction: 30mm) adjacent to each other in the left-right direction.

As shown in fig. 6, the relief pattern of the sub-joining region 50 is preferably formed such that a plurality of sub-relief portions 51 are arranged at intervals in the vertical direction and a plurality of rows of the sub-relief portions 51 are formed at intervals in the horizontal direction in a state of being offset from each other. Further, the length of each sub-relief 51 in the lateral direction is preferably 2mm to 5mm, and the length in the vertical direction is preferably 0.3 to 5 mm. Further, the interval between the sub-relief portions 51 in the vertical direction is preferably in the range of 5mm to 50 mm.

The secondary joining regions 50 are preferably formed at positions within 5mm from the edge portions 4a located on the left and right sides of the diaper. That is, it means that any one of the sub-embossed portions 51 provided in the sub-joined region 50 is arranged within the diaper edge 4a5 mm. For example, in fig. 6, the distance between the outermost edge of the secondary joining region 50 and the edge 4a of each side portion of the diaper is denoted by reference numeral S1. The distance S1 is preferably within 5 mm. By forming the sub-joint regions 50 within 5mm of the edge 4a of the diaper in this manner, even if the left and right edges of the front body outer cover and the back body outer cover are rolled up, the maximum width of the rolled-up portion can be controlled within 5mm, which is advantageous. As will be described later, the secondary joining region 50 may also reach the edge 4a of the diaper by a distance S1 of 0 mm. Since the sub joint region 50 has a lower joint strength than the main joint region 40, even if the cross section of the sub embossed portion 51 of the diaper edge 4a is exposed, the diaper edge 4a can be prevented from having a poor texture.

As shown in fig. 6, a region (non-joined region) having no joined portion is preferably present between the main joined region 40 and the sub joined region 50. In fig. 6, the width of the non-joined region existing between the primary joined region 40 and the secondary joined region 50 is indicated by symbol S2. For example, the width S2 of the non-joined region is preferably 0.5mm to 4mm, or 1mm to 3mm, more preferably 1.5mm or more. Thereby, when the disposable diaper is torn, the secondary joining region 50 becomes easy to peel when the side seal parts 4 are peeled. That is, the side seals 4 are generally peeled off from the inside of the diaper to the outside when peeled off. Therefore, the primary bonding region 40 is peeled off first, and then the rear secondary bonding region 50 is peeled off. Here, the non-joined region exists between the primary joined region 40 and the secondary joined region 50, so that the user can tear the side seal 4 with a force, and after tearing the primary joined region 40, the non-joined region further reaches the secondary joined region 50 directly, and the secondary joined region 50 is torn. Therefore, the user can feel that the side seal portion 4 is easily torn. In the present invention, since the side seal portion 4 has the primary joining region 40 and the secondary joining region 50, the width of the entire side seal portion 4 is wider than that of a side seal portion which has not had the secondary joining region 50 in the related art. In this regard, as described above, providing the non-joined region between the primary joined region 40 and the secondary joined region 50 can eliminate the situation where the side seal 4 is not easily torn due to the provision of the secondary joined region 50 by providing a feeling that the side seal 4 is easily torn by the user.

(2-3, Process for Forming side seal part)

Next, the steps of forming the side seal portions performed in the method of manufacturing the pants-type disposable diaper will be described with reference to fig. 7. The formation of the side seals is basically performed in the final stage of the manufacturing process of the pant-type disposable diaper. Fig. 7 is a conceptual flow diagram illustrating the final stages of a method of manufacturing a pant-type disposable diaper.

As shown in fig. 7, a plurality of diaper continuations 100' joined together in the left-right direction of the disposable diaper can be obtained according to a general manufacturing method (step S1). The diaper continuous body 100 ' is a continuous body 1a ' formed by connecting a plurality of front body outer garments in the left-right direction at positions where the side seals 4 are to be formed, and is a continuous body 2a ' formed by connecting a plurality of rear body outer garments in the left-right direction at positions where the side seals 4 are to be formed. Further, in the diaper continuous body 100 ', the absorbent body main body 3a is disposed so as to be perpendicular to the continuous body 1a ' of the front body outer covering and the continuous body 2a ' of the rear body outer covering. Here, in the diaper continuous body 100', it is preferable that the hot melt adhesive for fixing the waist stretch panel 20 and the mock worsted stretch panel 21 to the outer package is not applied to the intended formation position of the side seal parts 4. That is, the hot melt adhesive is intermittently applied along a part of the diaper continuous body 100' in the left-right direction (flow direction), and the intermittent portions 110 are adjusted to coincide with the predetermined forming positions of the side seal portions 4. Accordingly, there is no elastic stretchable material and no hot melt adhesive for fixing the stretchable member at the portion where the side seal part 4 is to be formed.

Next, the diaper continuous body 100' is folded in the vertical direction in the crotch region where the absorber main body 3a is disposed (step S2). Thereby, the continuous body 1a 'of the front body cover and the continuous body 2 a' of the rear body cover are superposed on each other. In this case, the intermittent portions 110 formed on the continuous body 1a 'side of the front body cover and the intermittent portions 110 formed on the continuous body 2 a' side of the rear body cover are positioned at the same positions.

Next, the side seals 4 are formed in the diaper continuous body 100' in which the front body and the back body are superposed (step S3). The side seal portions 4 are formed at positions corresponding to the left and right side portions of the front body and the rear body when the disposable diaper 100 of the individual pants type is formed. Here, as shown in fig. 7, the side seal 4 is formed at one time in a row for a right side portion of one pants-type disposable diaper and at a left side portion of another adjacent pants-type disposable diaper, 2 side by side. The term "forming 2 side seals 4 at a time" means that 2 embossing patterns are engraved on the pattern block of the embossing roll which is heat-sealed or ultrasonically sealed. Therefore, by introducing the diaper continuous body 100' between the embossing roll and the anvil roll as described above, 2 side seal portions 4 can be formed side by making the embossing roll and the anvil roll rotate only once. As shown in the enlarged view of the side seal portions 4 in fig. 7, each side seal portion 4 has the main joint region 40 and the sub joint region 50 provided closer to the predetermined cutting line (chain line) than the main joint region 40 as described above. As shown in the enlarged view of fig. 7, the side seal parts 4 of 2 strips are formed in a state where the respective sub joint regions 50 are adjacent to each other. That is, between the two sub joint regions 50, a predetermined cut line (chain line) of the diaper continuous body 100' is located.

Then, the diaper continuous body 100' having the side seal portions 4 formed thereon is cut in the vertical direction along a predetermined cutting line (chain line) between 2 side seal portions 4 (step S4). That is, the diaper continuous body 100' is cut at the boundaries of the 2 sub joint regions 50. Thereby, individual pant-type disposable diapers 100 can be cut from the diaper continuous body 100'. Through the above-described processes, the pants-type disposable diaper 100 of the present invention can be manufactured.

(2-4, other relief patterns of side seal parts)

Next, a pattern different from the relief pattern shown in fig. 3 and the like will be described with reference to fig. 8(a), 8(b), 9(a), and 9 (b). The relief patterns shown in fig. 8 and 9 are different from those shown in fig. 3 and the like, and at least 2 or more of the plurality of sub relief portions 51 formed in the sub joining region 50 reach the side ends 4a on both left and right sides of the front body 1 and the rear body 2. As shown in fig. 8 and 9, the plurality of sub-emboss portions 51 reach the left and right side edges 4a of the front body 1 and the rear body 2, and the left and right side edges 4a can be more reliably prevented from coming loose.

Specifically, in the embossed pattern of fig. 8 a, a plurality of sub-embossed portions 51 having a nearly elliptical shape are arranged in a row at intervals in the vertical direction along a predetermined cutting line (chain line) of the diaper continuous body. Therefore, by cutting the diaper continuous body along the predetermined cutting line, the plurality of sub-relief portions 51 on the predetermined cutting line are divided into 2. Thus, in the sub joint region 50 of each side seal part 4, the divided sub relief parts 51 reach the edge ends 4a on both the left and right sides of the diaper.

As shown in fig. 8(b), the sub-joint regions 50 are formed by a plurality of sub-embossed portions 51 in a short line shape, and the sub-joint regions 50 are concentrated in the vicinity of a predetermined cutting line (chain line). Further, on the predetermined cutting line, a plurality of sub-relief portions 51 in the form of short lines are also arranged in a row at intervals in the vertical direction. In the relief pattern shown in fig. 8(b), the row of sub-relief portions 51 arranged on the predetermined cutting line is vertically displaced from the row of adjacent sub-relief portions 51.

The relief pattern of fig. 9(a) is a modification of the relief pattern of fig. 8 (b). In the relief pattern shown in fig. 9(a), the rows of the sub-relief portions 51 arranged on the predetermined cutting line and the rows of the sub-relief portions 51 adjacent thereto are all shifted from each other in the vertical direction.

In the relief pattern shown in fig. 9(b), a plurality of linear sub-relief portions 51, which are long in the lateral direction and are long in the longitudinal direction, are arranged in a line in the vertical direction along a predetermined cutting line (chain line) across the predetermined cutting line. The linear sub-relief 51 has a length in the lateral direction of 3mm to 15mm, preferably 5mm to 10 mm. By cutting the diaper continuous body along a predetermined cutting line, the linear sub-embossed portion 51 is divided into 2 sub-joint regions 50. The embossed pattern shown in fig. 9(b) can more reliably prevent the edge portions of the side portions of the disposable diaper from being curled up.

The relief pattern in the side seal 4 is described above as a preferred embodiment. However, in the present invention, the relief pattern of the side seal 4 is not limited to the above-described form, and those skilled in the art can appropriately modify the above-described form within a range that is obvious from the above-described form.

(3, absorber body)

Finally, the structure of the absorbent body main body 3a supported by the front body exterior body 1a and the rear body exterior body 2a will be described.

The absorbent body 3a is supported in a state of being joined between the front body outer cover 1a and the back body outer cover 2a, and is positioned in the crotch of the wearer when the disposable diaper 100 is worn, and absorbs and supports liquid such as urine excreted by the wearer. The absorber body 3a is disposed across the front body 1 and the back body 2 with the crotch portion 3 of the disposable diaper as the center.

As shown in fig. 2, the absorbent body 3a basically includes an absorbent body 31, a front sheet 32, a back sheet 33, and a pair of three-dimensional folds 34.

The absorber 31 absorbs liquid such as urine and serves as a member for supporting the absorbed liquid. The absorbent body 31 is disposed between a liquid-permeable surface sheet 32 and a liquid-impermeable back side sheet 33. The absorbent body 31 has a function of absorbing the liquid passing through the top sheet 32 and is composed of an absorbent material. The absorbent material constituting the absorbent body 31 may be any known material. As the absorbent material, for example, sheet-like pulp, super absorbent polymer or hydrophilic sheet can be used. Further, the absorbent material may be one of sheet-like pulp, super absorbent polymer and hydrophilic sheet, or two or more thereof may be used in combination. The absorbent material is generally used in the form of a single-layer or multi-layer mat. The shape of the absorber 31 can be designed to appropriately match the shape, size, and use of the disposable diaper. For example, the absorbent body 31 may have an hourglass shape as shown in fig. 2. Further, the shape may be a rectangle, an ellipse, or a gourd shape as used in a general disposable diaper.

The topsheet 32 is a member for allowing liquid such as urine to penetrate into the absorbent body 31 by directly contacting the skin of the wearer's crotch. Therefore, the surface sheet 32 is made of a liquid-permeable material having high flexibility. The top sheet 32 is disposed so as to cover the absorbent body 31 on the side where the skin directly contacts. Examples of the non-permeable material constituting the surface sheet 32 are woven fabric, nonwoven fabric, or porous film. Further, for example, a nonwoven fabric may be further formed by hydrophilizing fibers of a thermoplastic resin such as polypropylene, polyethylene, polyester, or nylon.

The back side sheet 33 serves as a member for preventing liquid absorbed by the absorbent body 31 through the top sheet 32 from leaking to the outside of the diaper. Therefore, the back side panels 33 are composed of a liquid-impermeable material. Further, the back side sheet 33 covers the absorbent body 31 from the skin non-direct contact surface side in order to prevent liquid from leaking from the bottom surface of the absorbent body 31. An example of the non-penetrating material constituting the back side sheet 33 is a liquid-impermeable film composed of a polyethylene resin. In particular, a microporous polyethylene film having a plurality of micropores of 0.1 to 4 μm is preferably used.

A pair of three-dimensional folds 34 standing along both side edges of the absorbent body 31 for preventing the urine excreted by the wearer from leaking laterally. The three-dimensional corrugations 34 are each provided with a three-dimensional corrugation stretching material 35 at the distal end thereof, and rise in the direction of contact with the skin of the wearer when the three-dimensional corrugation stretching material 35 contracts. Therefore, the pair of three-dimensional folds 34 serve as a leakage preventing wall for urine, and can prevent urine that has not penetrated through the top sheet 32 or urine that has not been completely absorbed by the absorber 31 from leaking out of the openings around the legs of the disposable diaper. The three-dimensional fold 34 may be formed using conventional compositions commonly used in disposable diapers. The three-dimensional corrugations 34 can be formed by sandwiching and fixing a stretched three-dimensional corrugation stretching material 35 between layers of a water repellent sheet, for example. As the water repellent sheet, for example, a nonwoven fabric sheet obtained by a production method such as a card embossing or a spinning and binding method can be used, and a nonwoven fabric sheet such as SMS or SMMS having high water repellency is preferably used. The three-dimensional corrugated stretch member 35 is generally made of a linear elastic rubber. The rubber material may be styrene rubber, olefin rubber, urethane rubber, ester rubber, polyurethane, polyethylene, polystyrene, styrene-butadiene, silicone, polyester, or the like.

Industrial applicability

The present invention relates to a pant-type disposable diaper for infants or elderly persons. Therefore, the present invention is applicable to the nursery and nursing-related industries.

Description of the reference numerals

1 precursor

2 the back of the body

3 crotch part

4 side edge seal

1a front body cover

2a rear body cover

3a absorbent body

4a edge terminal

40 primary joining region

40a upper bonding area

40b part joint area

41 main relief part

41a upper relief part

41b lower relief part

50 secondary joining areas

51 sub-relief part

100 disposable diaper

100' diaper continuum

110 intermittent part

Claims

1. A method of manufacturing a pants-type disposable diaper having a front body (1) joined to the abdomen of a wearer, a rear body (2) joined to the back of the wearer, and a crotch portion (3) located between the front body (1) and the rear body (2), the method comprising the steps of:

a step of obtaining a diaper continuous body in which a plurality of disposable diapers are connected in a lateral direction;

folding back the diaper continuous body in the crotch part (3) and overlapping the front body (1) and the rear body (2);

a joining step of forming a single-side seal portion (4), the single-side seal portion (4) being formed by heat-sealing or ultrasonic-sealing the left and right sides of the front body (1) and the left and right sides of the rear body (2) by heat-sealing; and

a cutting step of cutting the diaper continuous body in the vertical direction at the positions corresponding to the edge portions (4a) of the front body (1) and the rear body (2) on the left and right sides to obtain individual pants-type disposable diapers;

wherein, the one-side sealing part (4) formed in the bonding process has a main bonding area (40) extending in the vertical direction and an auxiliary bonding area (50) located at the outer side of the main bonding area (40) in the left and right directions and extending in the vertical direction;

the auxiliary bonding region (50) is a region formed by arranging a plurality of auxiliary embossments (51) in a vertically spaced embossed row, and the bonding strength of the auxiliary bonding region (50) is weaker than that of the main bonding region (40);

in the cutting process, the diaper continuous body is cut in the vertical direction at the boundary position of the two secondary joint areas (50);

in the cutting step, at least 2 or more of the plurality of sub-embossed portions (51) formed in the sub-joined region (50) are divided, and the diaper continuous body is cut in the vertical direction.