CN114007564A

CN114007564A - Method for manufacturing sheet member for absorbent article, and absorbent article

Info

Publication number: CN114007564A
Application number: CN202080047427.0A
Authority: CN
Inventors: 川上祐介
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 2019-07-31
Filing date: 2020-07-17
Publication date: 2022-02-01
Also published as: JP2021023408A; WO2021020171A1; JP7438686B2

Abstract

The method comprises a conveying step (S101) of conveying a 1 st continuous body (2A) and a 2 nd continuous body (2B) each having a plurality of through holes (40), a joining region forming step (S102) of forming a plurality of joining regions (50) for attaching an elastic member (3) in a state of being stretched in a conveying direction of the 1 st continuous body (2A) or the 2 nd continuous body (2B) between the 1 st continuous body (2A) and the 2 nd continuous body (2B) laminated on one side in a thickness direction of the 1 st continuous body, and an elastic member cutting step (S103) of cutting the elastic member (3) in a stretched state between two joining regions (50) adjacent to each other in the conveying direction to contract the cut elastic member (3) in the conveying direction, so as not to be exposed from the through hole (40) to the other side in the thickness direction of the 1 st continuous body (2A).

Description

Method for manufacturing sheet member for absorbent article, and absorbent article

Technical Field

The present invention relates to a method for manufacturing a sheet member for an absorbent article and an absorbent article.

Background

Absorbent articles such as underpants type disposable diapers have been known. In such an absorbent article, in order to improve air permeability when worn, openings may be provided in the surface of a sheet member such as a nonwoven fabric constituting the absorbent article. For example, patent document 1 discloses a disposable wearing article including a perforated nonwoven fabric having a plurality of holes penetrating through front and back surfaces thereof at intervals.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-57810

Disclosure of Invention

Problems to be solved by the invention

In an absorbent article such as a disposable diaper, a stretchable elastic member such as a rubber thread is generally provided to impart stretchability, but the rubber thread or the like may be exposed to the outside from a through hole (an opening for air permeation) provided in a sheet member constituting the disposable diaper. Therefore, it is seen that users of the rubber thread or the like exposed from the through hole are likely to have negative impressions that the absorbent article is a defective article or that good fit cannot be obtained because the stretchability does not function reliably.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide an absorbent article sheet member in which an elastic member is not exposed from a through hole.

Means for solving the problems

The method for manufacturing a sheet member for an absorbent article of the main invention for achieving the above object comprises a conveying step, a joining region forming step, and an elastic member cutting step, the conveying step conveys the 1 st continuous body and the 2 nd continuous body which are provided with a plurality of through holes respectively, the joining region forming step of forming a plurality of joining regions to which elastic members in a state of being stretched in a conveying direction of the 1 st continuous sheet or the 2 nd continuous sheet are attached, between the 1 st continuous sheet and the 2 nd continuous sheet stacked on one side in a thickness direction of the 1 st continuous sheet, the elastic member cutting step cuts the elastic member in an extended state between two of the joining regions adjacent to each other in the conveying direction and contracts the cut elastic member in the conveying direction, so as not to be exposed from the through hole to the other side in the thickness direction of the 1 st continuous sheet.

Other features of the present invention will be apparent from the description of the specification and drawings.

Effects of the invention

The present invention can provide an absorbent article sheet member in which the elastic member is not exposed from the through hole.

Drawings

Fig. 1 is a schematic perspective view of a diaper 1 according to embodiment 1.

Fig. 2 is a schematic plan view of the diaper 1 in an unfolded and stretched state as viewed from the skin side.

Fig. 3 is a schematic sectional view taken along line a-a of fig. 2.

Fig. 4 is a schematic side view illustrating the manufacturing apparatus 100 for manufacturing the sheet member 2.

Fig. 5 is a flowchart showing a manufacturing process of the sheet member 2.

Fig. 6 is a schematic plan view showing an example of the arrangement of the bonding region 50.

Fig. 7A to 7C are diagrams illustrating a mechanism of exposing an elastic member from a through hole in a conventional stretchable sheet member provided with through holes.

Fig. 8 is a diagram illustrating a case of reverse movement in a case where the elastic member 3 is cut at a position closer to the joining region 50 (the 1 st joining region 501) provided on the upstream side in the conveying direction.

Fig. 9 is a diagram illustrating a reverse movement in the case where the elastic member 3 is cut at a position closer to the joining region 50 (2 nd joining region 502) provided on the downstream side in the conveying direction.

Fig. 10 is a schematic cross-sectional view of the sheet member 2 in the present embodiment.

Fig. 11A to 11C are schematic explanatory views for explaining a conventional method for forming an apertured nonwoven fabric.

Fig. 12A to 12C are schematic explanatory views for explaining a method of forming an apertured nonwoven fabric according to the present embodiment.

Fig. 13 is a schematic cross-sectional view showing a case where the diameter of the through-hole 40 is different between one side and the other side in the thickness direction.

Fig. 14 is a schematic plan view of the diaper 5 of embodiment 2 in an unfolded and extended state.

Fig. 15 is a schematic sectional view taken along line B-B of fig. 14.

Fig. 16 is a schematic side view illustrating a manufacturing apparatus 200 for manufacturing the sheet member 6.

Fig. 17 is a schematic plan view showing an example of the arrangement of the bonding region 50.

Fig. 18 is a schematic plan view illustrating a modification of the joining region 50.

Fig. 19A and 19B are explanatory diagrams of a function of attaching the elastic member 3 by the pair of fusion-bonded portions 52S.

Detailed Description

At least the following matters will be clear from the description of the present specification and the accompanying drawings.

A method for manufacturing a sheet member for an absorbent article, comprising a conveying step, a joining region forming step, and an elastic member cutting step, the conveying step conveys the 1 st continuous body and the 2 nd continuous body which are provided with a plurality of through holes respectively, the joining region forming step forms a plurality of joining regions for attaching an elastic member in a state of being stretched in a conveying direction of the 1 st continuous sheet or the 2 nd continuous sheet between the 1 st continuous sheet and the 2 nd continuous sheet stacked on one side in a thickness direction of the 1 st continuous sheet, the elastic member cutting step cuts the elastic member in an extended state between two of the joining regions adjacent to each other in the conveying direction to contract the cut elastic member in the conveying direction, so as not to be exposed from the through hole to the other side in the thickness direction of the 1 st continuous sheet.

With the method for manufacturing a sheet member for an absorbent article, the elastic member can be made less likely to be exposed from the through hole provided in the sheet member. Therefore, when an absorbent article is manufactured using the sheet member, it is difficult to see that the elastic member (rubber thread or the like) is exposed from the through hole. This makes it difficult for the user to give an impression that the absorbent article is a defective article or that good fit cannot be obtained because stretchability does not function reliably.

In the method for manufacturing a sheet member for an absorbent article, it is preferable that the joining region includes a 1 st joining region and a 2 nd joining region, the 2 nd joining region and the 1 st joining region are adjacent to each other on a downstream side in the conveying direction, and in the cutting step, the elastic member is cut at a position closer to the 1 st joining region than the 2 nd joining region in the conveying direction.

With such a method for manufacturing a sheet member for an absorbent article, the contraction force when the elastic member contracts (moves in the opposite direction) from the cut position toward the joined region can be made relatively small. Thus, the elastic member is less likely to be caught by the outer edge of the through hole, and exposure of the elastic member from the through hole is easily suppressed.

In the method for manufacturing a sheet member for an absorbent article, it is preferable that the height of a portion of the outer edge of the through hole protruding in the thickness direction is 0.2mm or less.

With such a method of manufacturing a sheet member for an absorbent article, when the elastic member contracts (moves in the reverse direction), the elastic member can be prevented from catching on the outer edge portion of the through hole. Thus, the elastic member can be effectively inhibited from being exposed from the through hole.

In the method for manufacturing a sheet member for an absorbent article, it is preferable that the diameter of the through hole is 3 times or less the diameter of the elastic member.

With the method for manufacturing a sheet member for an absorbent article, it is possible to provide a sheet member in which good air permeability is ensured and an elastic member is less likely to be exposed from a through hole.

In the method for manufacturing a sheet member for an absorbent article, it is preferable that the diameter of the through hole is smaller than twice the diameter of the elastic member.

With such a method of manufacturing a sheet member for an absorbent article, the elastic member is less likely to pass through the through-hole during the contraction (reverse movement) of the elastic member. This can suppress the elastic member from being exposed from the through hole with high accuracy.

In the method for manufacturing a sheet member for an absorbent article, it is preferable that a diameter of the through hole on the one side in the thickness direction is smaller than a diameter of the through hole on the other side in the thickness direction.

With such a method for manufacturing a sheet member for an absorbent article, the elastic member is prevented from being exposed from one side (skin side) to the other side (non-skin side) in the thickness direction of the through hole, and the through hole is easily visible from the other side (non-skin side), and the user can easily recognize that the sheet member has good air permeability.

In the method for producing a sheet member for an absorbent article, it is preferable that the through-hole is formed by inserting a pin from one side to the other side in the thickness direction of the 1 st continuous sheet, and the pin is heated to a temperature of not less than the softening point of the thermoplastic fibers contained in the 1 st continuous sheet and less than the melting point of the thermoplastic fibers at the time of forming the through-hole.

In the method for manufacturing the sheet member for an absorbent article, since the pin portion can be pushed in and pulled out while heating the 1 st continuous sheet, the pin portion can be easily inserted into the 1 st continuous sheet softened by heating, and the hole shape of the formed through hole can be easily maintained.

In the method for producing a sheet member for an absorbent article, it is preferable that the pin is heated to a temperature close to the softening point than the melting point of the thermoplastic fibers contained in the 1 st continuous sheet body when the through hole is formed.

In the method for manufacturing the sheet member for an absorbent article, the fibers in the hole portion are likely to shrink and the diameter of the through hole is likely to decrease by forming the hole at the heating temperature of the pin portion as low as possible.

In the method for manufacturing a sheet member for an absorbent article, it is preferable that the joining region includes a 1 st joining region and a 2 nd joining region, the 2 nd joining region and the 1 st joining region are adjacent to each other on a downstream side in the transport direction, and an adhesive is provided between the 1 st joining region and the 2 nd joining region in the transport direction.

In the method for manufacturing a sheet member for an absorbent article, since the elastic member is lightly fixed by the adhesive, the elastic member is less likely to swing during contraction. Therefore, the elastic member is less likely to be caught by the outer edge of the through hole during contraction, and the elastic member is more likely to be inhibited from being exposed from the through hole.

In the method for producing an absorbent article sheet member, it is preferable that the absorbent article sheet member is a body surrounding part member of a pants-type disposable diaper, the elastic member is a bonded gather (japanese patent No. フィットギャザー) elastic member that imparts stretchability to the body surrounding part member, and at least a part of the bonded gather elastic member is cut in the elastic member cutting step.

By the method for manufacturing a sheet member for an absorbent article, a sheet member that can be used to manufacture a pants-type disposable diaper in which a gathered elastic member is not exposed from a through hole in a body peripheral portion can be provided.

In the method for producing an absorbent article sheet member, it is preferable that the absorbent article sheet member is an outer cover of a tape-type disposable diaper, the elastic member is a crotch-region gather (japanese patent No. クロッチギャザー) elastic member which imparts stretchability to a crotch region of the outer cover, and at least a part of the crotch-region gather elastic member is cut in the elastic member cutting step.

By the method for manufacturing a sheet member for an absorbent article, a sheet member for a tape-type disposable diaper in which a crotch region gather elastic member is not exposed from a through hole in a crotch region can be manufactured.

Further, an absorbent article having a vertical direction and a horizontal direction intersecting each other, comprising a sheet member, the sheet member has a 1 st sheet member, a 2 nd sheet member, an elastic member, and a joining portion, the 1 st sheet member is provided with a plurality of through holes on a surface thereof, the 2 nd sheet member is laminated on the skin side of the 1 st sheet member, and the elastic member is provided between the 1 st sheet member and the 2 nd sheet member in an expanded state in the left-right direction, a plurality of the joining portions for attaching the elastic member to the 1 st sheet member and the 2 nd sheet member, wherein the elastic member cut between two of the joining portions adjacent to each other in the left-right direction contracts in the left-right direction so as not to be exposed from the through hole to the non-skin side of the 1 st sheet member.

With such an absorbent article, it is not easy to see that the elastic member (rubber thread or the like) is exposed from the through hole. This makes it difficult for the user to give an impression that the absorbent article is a defective article or that good fit cannot be obtained because stretchability does not function reliably.

In the absorbent article, it is preferable that the elastic member is provided in plurality at intervals in the vertical direction, and the elastic members are cut at positions different from each other in the horizontal direction.

With such an absorbent article, the mark formed by cutting the elastic member is less likely to be conspicuous on the non-skin-side surface of the absorbent article (the 1 st sheet member), and the appearance of the absorbent article can be improved.

In the absorbent article, it is preferable that the height of a portion of the outer edge portion of the through hole protruding toward the skin side is 0.2mm or less.

With such an absorbent article, the elastic member can be prevented from catching on the outer edge portion of the through hole when the elastic member contracts (moves in the reverse direction). Therefore, an absorbent article in which the elastic member is less likely to be exposed from the through hole can be realized.

In the absorbent article, the diameter of the through hole is preferably 3 times or less the diameter of the elastic member.

With such an absorbent article, it is possible to realize an absorbent article in which good air permeability is ensured and the elastic member is less likely to be exposed from the through hole.

In the absorbent article, it is preferable that the diameter of the through hole is smaller than twice the diameter of the elastic member.

With such an absorbent article, the elastic member is less likely to pass through the through-hole when the elastic member contracts (moves in the reverse direction). This makes it possible to realize an absorbent article in which exposure of the elastic member from the through hole is suppressed with high accuracy.

In the absorbent article, it is preferable that the diameter of the through hole on the skin side is smaller than the diameter of the through hole on the non-skin side.

With such an absorbent article, the elastic member is prevented from being exposed from one side (skin side) to the other side (non-skin side) in the thickness direction of the through hole, and the through hole is easily visible from the other side (non-skin side), and the user can easily recognize that the absorbent article has good air permeability.

In the absorbent article, it is preferable that the 1 st sheet member is a nonwoven fabric including thermoplastic fibers, and a ratio of a portion of the thermoplastic fibers which is not melted is larger than a ratio of a portion of the thermoplastic fibers which is melted at an outer edge portion of the through-hole.

With such an absorbent article, the rigidity at the outer edge portion of the through hole can be reduced. Therefore, the elastic member is not easily hooked to the outer edge portion when the elastic member is contracted (moved in the reverse direction), and the elastic member is not easily exposed from the through hole. In addition, in the region where the through-hole is formed, an absorbent article having a good feel can be realized.

In the absorbent article, it is preferable that the sheet member is a body surrounding part member of a pants-type disposable diaper, the elastic member is a fit gather elastic member that imparts stretchability to the body surrounding part member, and at least a part of the fit gather elastic member is cut at a predetermined position in the left-right direction.

With such an absorbent article, a pants-type disposable diaper can be realized in which the gather elastic member is attached to the body peripheral portion without being exposed through the through hole.

In the absorbent article, it is preferable that the sheet member is an outer cover of a tape-type disposable diaper, the elastic member is a crotch-region-gather elastic member that imparts stretchability to a crotch region of the outer cover, and at least a part of the crotch-region-gather elastic member is cut at a predetermined position in the up-down direction.

With such an absorbent article, a belt-type disposable diaper in which the crotch region gather elastic member is not exposed from the through hole in the crotch region can be realized.

In addition to this absorbent article, it is preferable that the absorbent article has a longitudinal direction along the vertical direction in the unfolded state, and a distance between an abdomen-side end of the unfolded absorbent article and an abdomen-side end of a portion where stretchability of the crotch-region gather elastic member acts is larger than a distance between a back-side end of the unfolded absorbent article and a back-side end of a portion where stretchability of the crotch-region gather elastic member acts in the longitudinal direction.

With such an absorbent article, even if the elastic member is cut at any position in the longitudinal direction in the abdomen-side region, the crotch region gather elastic member is less likely to be exposed from the through-hole.

Embodiment 1

An underpants type disposable diaper 1 (hereinafter, also simply referred to as "diaper 1") for infants will be described as an example of the absorbent article of embodiment 1. However, the present invention is not limited to the above, and the absorbent article of embodiment 1 can be applied to a disposable diaper for adults.

Basic structure of underpants type disposable diaper 1

Fig. 1 is a schematic perspective view of a diaper 1 according to embodiment 1. Fig. 2 is a schematic plan view of the diaper 1 in an unfolded and stretched state as viewed from the skin side. Fig. 3 is a schematic sectional view taken along line a-a of fig. 2. The "stretched state" of the diaper 1 is a state in which the diaper 1 is stretched without wrinkles, and is a state in which the diaper is stretched to a length at which the size of each member (for example, an abdominal side portion 20 described later) constituting the diaper 1 matches or is close to matching the size of the member.

The diaper 1 has an absorbent main body 10, an abdomen-side portion 20 and a back-side portion 30. The absorbent main body 10 is disposed between the wearer's thighs. The abdomen side portion 20 and the back side portion 30 are also "sheet members 2" which are closely attached to the girth portion of the wearer. As shown in fig. 1, the diaper 1 in the pants-type state has a vertical direction, a horizontal direction, and a thickness direction which are orthogonal to each other. In the thickness direction, the side that contacts the wearer is referred to as the skin side, and the side that does not contact the wearer is referred to as the non-skin side. In fig. 2 and 3, the diaper 1 in the unfolded and extended state has a longitudinal direction, a width direction, and a thickness direction which are orthogonal to each other. The longitudinal direction is a direction along the vertical direction in the pants-type state of fig. 1, and the lateral direction is a direction along the horizontal direction in the pants-type state.

In the diaper 1 in the developed state of fig. 2, the center portion in the width direction of the abdomen side portion 20 overlaps with one end portion in the longitudinal direction of the absorbent main body 10, and the center portion in the width direction of the back side portion 30 overlaps with the other end portion in the longitudinal direction of the absorbent main body 10. The diaper 1 in the developed state is folded in two at a substantially central portion C10 in the longitudinal direction, and both side portions in the width direction (left-right direction) of the abdomen side portion 20 and the back side portion 30 are joined by welding or the like, respectively, to provide the diaper 1 in the pants-type state shown in fig. 1.

The absorbent body 10 can be exemplified by one having an absorbent body 11, a liquid-permeable top sheet (not shown) disposed closer to the skin side than the absorbent body 11, and a liquid-impermeable back sheet (not shown) disposed closer to the non-skin side than the absorbent body 11. The absorbent body 11 absorbs and retains excrement such as urine, and can be exemplified by a structure obtained by forming liquid absorbent fibers such as pulp containing Super Absorbent Polymer (SAP) into a predetermined shape.

As shown in fig. 3, the abdomen-side portion 20 and the back-side portion 30 respectively have skin-

side nonwoven fabrics

21 and 31 arranged on the skin side in the thickness direction thereof, non-skin-

side nonwoven fabrics

22 and 32 arranged on the non-skin side of the skin-

side nonwoven fabrics

21 and 31, adhesive gather

elastic members

23 and 33, and cover

nonwoven fabrics

24 and 34. The skin-

side nonwoven fabrics

21, 31 and the non-skin-

side nonwoven fabrics

22, 32 are disposed on the non-skin side of the absorbent main body 10. The

cover nonwoven fabrics

24, 34 are disposed closer to the skin side than the absorbent main body 10, have a length in the longitudinal direction (vertical direction) shorter than the skin side

nonwoven fabrics

21, 31, etc., and cover the ends in the longitudinal direction of the absorbent main body 10.

The skin-

side nonwoven fabrics

21, 31, the non-skin-

side nonwoven fabrics

22, 32, and the

cover nonwoven fabrics

24, 34 are nonwoven fabrics having thermoplastic resin fibers. For example, a nonwoven fabric composed of individual fibers of thermoplastic resin such as polypropylene (PP) and Polyethylene (PE), and composite fibers such as a sheath-core structure of PP and PE can be exemplified.

The plurality of bonded gather

elastic members

23 and 33 are arranged in the vertical direction between the skin-

side nonwoven fabrics

21 and 31 and the non-skin-

side nonwoven fabrics

22 and 32, and are attached in a state of being stretched in the horizontal direction. This imparts stretchability in the left-right direction to the abdomen-side section 20 and the back-side section 30. Examples of the bonded

elastic members

23 and 33 include filament-like rubbers and spandex fibers.

In addition, a plurality of through holes 40 penetrating the non-skin side

nonwoven fabrics

22, 32 in the thickness direction are formed in the abdomen side portion 20 and the back side portion 30. That is, the non-skin side

nonwoven fabrics

22 and 32 in the present embodiment are perforated nonwoven fabrics having a plurality of openings. The through holes 40 are formed in a predetermined pattern on the entire non-skin side

nonwoven fabrics

22, 32. For example, in the diaper 1, as shown in fig. 2, circular holes are distributed at predetermined intervals in a so-called staggered arrangement. However, the shape and number of the through holes 40 and the arrangement of the through holes 40 are not particularly limited, and are not limited to the example of fig. 2.

By providing such through holes 40, good air permeability of the abdomen side portion 20 and the back side portion 30 is ensured when the diaper 1 is put on. The through-hole 40 may be formed only in one of the abdomen side portion 20 and the back side portion 30. The through-holes 40 may be formed so as to penetrate through both the skin-

side nonwoven fabrics

21, 31 and the non-skin-

side nonwoven fabrics

22, 32 in the thickness direction.

Method for manufacturing sheet member 2

A method for producing the sheet member 2 constituting the abdomen side portion 20 (back side portion 30) in the diaper 1 will be described. Since the abdomen side portion 20 and the back side portion 30 have substantially the same structure as shown in fig. 3, the abdomen side portion 20 will be described below, and the back side portion 30 will not be described.

The abdomen side portion 20 in the present embodiment is formed by a sheet member 2 having stretchability in a predetermined shape. Specifically, the sheet member 2 is a sheet-like member in which a plurality of

abdomen side portions

20 and 20 … … are continuous in a predetermined direction (direction corresponding to the left-right direction). In the following description, in the method of manufacturing the sheet member 2, a continuous body of nonwoven fabric corresponding to the non-skin side nonwoven fabric 22 provided with the plurality of through

holes

40, 40 … … is referred to as the 1 st continuous body 2A. Similarly, a continuous nonwoven fabric corresponding to the skin-side nonwoven fabric 21 is referred to as a 2 nd continuous sheet 2B. The elastic member 3 is an elastic member corresponding to a continuous state where the gathered elastic member 23 is bonded.

Fig. 4 is a schematic side view illustrating the manufacturing apparatus 100 for manufacturing the sheet member 2. Fig. 5 is a flowchart showing a manufacturing process of the sheet member 2. The manufacturing apparatus 100 shown in fig. 4 successively performs the respective steps (S101 to S103) shown in fig. 5, thereby continuously manufacturing the sheet member 2 (the abdomen side portion 20 of the diaper 1). The manufacturing apparatus 100 includes a conveying mechanism 110, a bonding region forming mechanism 120, and an elastic member cutting mechanism 130.

First, a conveying step of conveying various base materials constituting the sheet member 2 in a predetermined conveying direction is performed (S101). In the manufacturing apparatus 100, the transport direction is a direction along the left-right direction of the diaper 1 (the abdomen side portion 20). In the transport step, the 1 st continuous body 2A formed by connecting the non-skin-side nonwoven fabrics 22 in the transport direction is transported from the upstream side to the downstream side in the transport direction at a predetermined transport speed by the transport mechanism 110 provided with a plurality of transport rollers. Similarly, the 2 nd continuous body 2B formed by connecting the skin-side nonwoven fabric 21 in the transport direction is transported from the upstream side to the downstream side in the transport direction at a predetermined transport speed by the transport mechanism 110. The elastic member 3 formed by connecting the bonded-wrinkle elastic members 23 in the conveyance direction is conveyed from the upstream side to the downstream side in the conveyance direction at a predetermined conveyance speed by the conveyance mechanism 110.

In fig. 4, a plurality of through

holes

40 and 40 … … are formed in advance in the non-skin side nonwoven fabric 22 (the 1 st continuous sheet 2A). That is, the 1 st continuous sheet 2A is supplied to the manufacturing apparatus 100 as a perforated nonwoven fabric. However, the 1 st continuous body 2A may be supplied as a non-perforated nonwoven fabric and may be formed with the through-holes 40 in the middle of conveyance in the conveyance direction. The method of forming the through hole 40 in this case will be described later.

Next, a joining region forming step (S102) of forming a plurality of joining

regions

50 and 50 … … for attaching the elastic member 3 to the 1 st continuous piece 2A and the 2 nd continuous piece 2B is performed. As shown in fig. 4, the 1 st continuous body 2A and the 2 nd continuous body 2B are conveyed in a stacked manner in the thickness direction. The elastic member 3 is arranged between the 1 st continuous piece 2A and the 2 nd continuous piece 2B in the thickness direction thereof in a state of being elongated in the conveyance direction at a predetermined elongation ratio, and the elastic member 3 is attached so as to be sandwiched between the 1 st continuous piece 2A and the 2 nd continuous piece 2B via the joining region 50.

In the bonding region forming step, a bonding material such as a hot melt adhesive is applied to each base material conveyed in the conveying direction by the bonding region forming means 120, thereby forming the bonding region 50. In fig. 4, a sheet member adhesive application section 122 and an elastic member adhesive application section 123 are provided as the joining region forming means 120. Then, the sheet member adhesive application section 122 applies the bonding material to the opposing surfaces of the 1 st continuous body 2A and the 2 nd continuous body 2B during conveyance, and the elastic member adhesive application section 123 applies the bonding material to the surface of the elastic member 3 during conveyance.

Fig. 6 is a schematic plan view showing an example of the arrangement of the bonding region 50. A sheet cutting position EC indicated by a broken line in fig. 6 indicates a position at which the sheet member 2 is cut in a subsequent step (step of manufacturing the diaper 1 using the sheet member 2). That is, the abdomen side portion 20 (diaper 1) is formed by cutting the sheet member 2 at two sheet cutting positions EC, EC adjacent to each other in the conveyance direction.

At least two joining regions 50 are formed in a region between two sheet cutting positions EC, EC adjacent to each other in the conveying direction. In the example of fig. 6, two bonding regions 50, i.e., a 1 st bonding region 501 and a 2 nd bonding region 502, are formed between two adjacent sheet cutting positions EC and EC. The 2 nd joining region 502 is provided at a predetermined interval downstream of the 1 st joining region 501 in the conveying direction, and the elastic member 3 in an expanded state in the conveying direction is attached between the 1 st continuous sheet 2A and the 2 nd continuous sheet 2B by these joining regions 50. This imparts stretchability in the conveyance direction (the lateral direction of the diaper 1) to the sheet member 2.

In fig. 6, a plurality of rectangular joint portions are arranged in a direction orthogonal to the conveyance direction (also referred to as "CD direction") to form the joint region 50, but the shape and size of the joint region 50 are not limited to the example of fig. 6. In addition, other bonding regions may be provided in addition to the 1 st bonding region 501 and the 2 nd bonding region 502.

Next, an elastic member cutting step (S103) of cutting the elastic member 3 in the state of being stretched in the conveyance direction between the two joining

regions

50, 50 adjacent to each other in the conveyance direction is performed. The elastic member is cut by an elastic member cutting mechanism 130. The elastic member cutting mechanism 130 has an anvil roller 132 and a pair of cutter rollers 131. The cutter roll 131 and the anvil roll 132 have rotation axes both along the CD direction, and are provided at positions facing each other in the thickness direction of the sheet member 2 (see fig. 4). Then, only the elastic member 3 is cut by sandwiching the sheet member 2 being conveyed between the cutter blades provided on the circumferential surface of the cutter roller 131 and the anvil provided on the circumferential surface of the anvil roller 132.

For example, in fig. 6, the elastic member 3 in an extended state is cut at an elastic member cutting position CP between a 1 st joining region 501 and a 2 nd joining region 502 adjacent to each other in the conveying direction. Then, the cut elastic member 3 contracts from the elastic member cutting position CP toward the 1 st joining region 501 toward the upstream side in the conveying direction, and contracts from the elastic member cutting position CP toward the 2 nd joining region 502 toward the downstream side in the conveying direction. In this way, the action of contracting the cut elastic member 3 is also referred to as "reverse movement (japanese: カットバック)". In fig. 6, a part of the plurality of

elastic members

3 and 3 is provided to perform a reverse movement, and the stretchability in the left-right direction (conveying direction) is not exhibited in a predetermined region of the sheet member 2. This region is a region overlapping and joined to the absorbent main body 10 in the manufacturing process of the diaper 1, and by weakening the stretchability in the left-right direction in this region, the absorbent main body 10 can be suppressed from contracting in the left-right direction, and it is possible to make it difficult for excrement such as urine to leak.

The cutting position CP indicates a position at which the elastic member 3 in the stretched state is first cut. For example, in the case where the elastic member 3 is cut at a plurality of positions in the conveying direction by the elastic member cutting mechanism 130, the position at which the elastic member 3 is first cut at the plurality of positions is set as the cutting position CP.

In fig. 6, the cutting position CP is provided at the same position in the conveying direction (left-right direction). That is, fig. 6 shows an example in which a plurality of

elastic members

3 and 3 … … are provided with an interval in the CD direction (vertical direction) and are cut at the same position in the conveyance direction. However, the cutting positions CP in the conveying direction of the plurality of

elastic members

3 and 3 … … may be different from each other. By shifting the cutting position of each elastic member 3 in the left-right direction, the trace formed by cutting the elastic member 3 in the abdomen-side portion 20 (non-skin-side nonwoven fabric 22) of the diaper 1 becomes inconspicuous, and the appearance of the diaper 1 can be improved.

By such an operation, the sheet member 2 having stretchability in the left-right direction (conveying direction) is manufactured. Although not shown in fig. 4, various steps for manufacturing the diaper 1 are performed on the downstream side in the conveyance direction of the manufacturing apparatus 100. For example, a step of joining the absorbent main body 10 and the sheet member 2 (the abdomen side portion 20 and the back side portion 30), a step of folding the sheet member 2 in two at a predetermined position in the CD direction (the substantially central portion C10 in the longitudinal direction described above), a step of joining the sheet members 2 and 2 (the abdomen side portion 20 and the back side portion 30) overlapped in the thickness direction to each other at a predetermined position in the conveyance direction (a position corresponding to both side portions in the left-right direction of the abdomen side portion 20 and the back side portion 30), a step of cutting the sheet member 2 at the sheet cutting position EC, and the like are performed. In this way, a pants-type diaper 1 as shown in fig. 1 is manufactured.

About the through-hole 40

Conventionally, when the sheet member 2 (the abdomen-side portion 20 and the back-side portion 30) is manufactured as described above, when the sheet member 2 is provided with a plurality of through holes 40, there is a problem that the elastic member 3 is exposed to the outside of the sheet member 2 from the through holes 40 when the elastic member 3 moves in the reverse direction. Fig. 7A to 7C are diagrams illustrating a mechanism of exposing an elastic member from a through hole in a conventional stretchable sheet member (perforated nonwoven fabric) provided with through holes.

Fig. 7A is a cross section of a perforated nonwoven fabric NW1 (corresponding to the 1 st continuous body 2A) and a nonwoven fabric NW2 (corresponding to the 2 nd continuous body 2B) laminated in the thickness direction and a rubber thread S (corresponding to the elastic member 3) provided therebetween, as viewed from the CD direction. The rubber thread S is disposed in an extended state in the conveyance direction. The perforated nonwoven fabric NW1 is provided with through holes h. As shown in fig. 7A, a protruding portion hp protruding to one side in the thickness direction is formed near the outer edge of the through hole h. The protruding portion hp is a so-called "burr", and has been naturally formed when a through hole is formed in a nonwoven fabric.

When the rubber thread S is cut from the state of fig. 7A and the rubber thread S contracts (moves in the reverse direction) in the conveying direction, the surface of the rubber thread S is caught by the protruding portion hp formed at the outer edge portion of the through hole h at the time of contraction, and as shown in fig. 7B, the rubber thread S may be deformed into an Ω shape from the through hole h and exposed to the outside of the perforated nonwoven fabric NW 1. That is, the rubber thread S may be exposed from one side to the other side in the thickness direction of the perforated nonwoven fabric NW 1. Further, the stronger the contraction force of the rubber wire S, the greater the impact when hooking with the protrusion hp, and the more easily the rubber wire S is exposed from the through hole h.

In addition, in the diaper manufacturing process, the perforated nonwoven fabric NW1 is conveyed and folded, and the cut end of the rubber thread S may be exposed to the outside of the perforated nonwoven fabric NW1 from the through hole h as shown in fig. 7C. When a diaper was produced using such a sheet member, it was observed that the rubber was exposed from the ventilation holes (through holes h). Therefore, the user is liable to have a negative impression that the diaper is a defective product or that the stretch property does not surely function and good fit cannot be obtained.

In contrast, in the present embodiment, when the elastic member 3 is moved in the reverse direction in the elastic member cutting step (S103) described above in the production of the sheet member 2, the elastic member 3 can be made less likely to be exposed from the through-holes 40 of the non-skin-side nonwoven fabric 22. Specifically, when the elastic member 3 is cut between two joining

regions

50, 50 adjacent to each other in the conveying direction, the elastic member 3 is cut at a position closer to the joining region 50 disposed on the upstream side in the conveying direction than the joining region 50 disposed on the downstream side in the conveying direction.

Fig. 8 is a diagram illustrating a case of reverse movement in a case where the elastic member 3 is cut at a position close to the joining region 50 (the 1 st joining region 501) provided on the upstream side in the conveying direction. Fig. 9 is a diagram illustrating a situation of the reverse movement in the case where the elastic member 3 is cut at a position close to the joining region 50 (2 nd joining region 502) provided on the downstream side in the conveying direction. In fig. 8 and 9, as in fig. 6, the 1 st bonding region 501 and the 2 nd bonding region 502 are disposed adjacent to each other from the upstream side toward the downstream side in the conveying direction. Further, an intermediate position between the 1 st joining region 501 and the 2 nd joining region 502 in the conveying direction is C50. Further, the sheet member 2 is conveyed from the upstream side to the downstream side in the conveying direction at a predetermined speed V1.

In fig. 8, the elastic member 3 is cut at a position upstream of the intermediate position C50 in the conveying direction. That is, the distance between the cutting position CP of the elastic member 3 and the 1 st joining region 501 is shorter than the distance between the cutting position CP of the elastic member 3 and the 2 nd joining region 502 in the conveying direction. Therefore, as shown by the arrow in fig. 8, the contraction speed V31 of the elastic member 3 from the cutting position CP to the upstream side in the conveying direction (the 1 st joining region 501) is smaller than the contraction speed V32 from the cutting position CP to the downstream side in the conveying direction (the 2 nd joining region 502).

At this time, the sheet member 2 continues to move downstream in the conveying direction at the speed V1. Therefore, when the relative contraction amount of the elastic member 3 moving to the upstream side in the conveying direction per unit time with respect to the sheet member 2 is WD1, WD1 is equal to V31+ V1. When the relative contraction amount of the elastic member 3 moving to the downstream side in the conveyance direction per unit time is WD2, WD2 is equal to V32 to V1 (see fig. 8).

In contrast, in fig. 9, the elastic member 3 is cut at a position downstream of the intermediate position C50 in the conveying direction. That is, the distance between the cutting position CP of the elastic member 3 and the 1 st joining region 501 is longer than the distance between the cutting position CP of the elastic member 3 and the 2 nd joining region 502 in the conveying direction. Therefore, as shown by the arrow in fig. 9, the contraction speed V33 of the elastic member 3 from the cutting position CP to the upstream side in the conveying direction (the 1 st joining region 501) is greater than the contraction speed V34 from the cutting position CP to the downstream side in the conveying direction (the 2 nd joining region 502).

When the relative contraction amount of the elastic member 3 moving to the upstream side in the conveying direction per unit time with respect to the sheet member 2 is WD3, WD3 is equal to V33+ V1. When the relative contraction amount of the elastic member 3 moving to the downstream side in the conveyance direction per unit time is WD4, WD4 is set to V34 to V1 (see fig. 9).

Comparing fig. 8 and 9, it is understood that the contraction amount per unit time of the elastic member 3 in the upstream side in the conveying direction in fig. 8 is smaller (WD1< WD 3). This is because the contraction speed V31 of the elastic member 3 on the upstream side in the conveying direction in fig. 8 is smaller than the contraction speed V33 of the elastic member 3 on the upstream side in the conveying direction in fig. 9. That is, by cutting the elastic member 3 at a position closer to the joining region 50 (the 1 st joining region 501) provided on the upstream side in the conveying direction than the joining region 50 (the 2 nd joining region 502) provided on the downstream side in the conveying direction, the contraction force of the elastic member 3 on the upstream side in the conveying direction can be reduced.

In fig. 7, it is described that the rubber thread S is more likely to be engaged with the protruding portion hp on the outer edge of the through hole h and more likely to be exposed as the contraction force is stronger when the rubber thread S contracts, but in the present embodiment, the contraction force of the elastic member 3 is weakened as shown in fig. 8, and thereby the exposure of the elastic member 3 from the through hole 40 can be easily suppressed.

As is clear from fig. 8 and 9, the contraction force of the elastic member 3 toward the downstream side in the conveying direction is relatively smaller than the contraction force toward the upstream side in the conveying direction (WD1> WD2, WD3> WD 4). Therefore, when the exposure of the elastic member 3 from the through hole 40 can be suppressed on the upstream side in the conveying direction, the possibility that the elastic member 3 is exposed from the through hole 40 on the downstream side in the conveying direction is low.

Further, an adhesive may be provided between the 1 st bonding region 501 and the 2 nd bonding region of the sheet member 2 in the conveying direction. For example, an adhesive may be applied between the 1 st bonding area 501 and the 2 nd bonding area to have a degree of adhesive force enabling the elastic member 3 to perform reverse movement. When the elastic member 3 is lightly fixed to the sheet member 2 by such an adhesive, the elastic member 3 is less likely to swing in the CD direction or other directions when the elastic member 3 moves (contracts) in the reverse direction in the conveying direction. That is, the adhesive functions to prevent the swing, so that the contraction operation of the elastic member 3 is easily stabilized, and the elastic member is less likely to be caught by the outer edge portion 40e of the through hole 40. This makes it easier to suppress the elastic member 3 from being exposed from the through hole 40.

In addition to the adjustment of the cutting position of the elastic member 3, the shape of the through hole 40 can be adjusted as follows to suppress the elastic member 3 from being exposed from the through hole 40.

Fig. 10 is a schematic cross-sectional view of the sheet member 2 in the present embodiment, and corresponds to fig. 7. In fig. 10, the outer edge portion 40e of the through hole 40 hardly protrudes in the thickness direction. More specifically, the protrusion height h40e of the outer edge portion 40e in the thickness direction is equal to or less than a predetermined position. That is, no large protruding portion (burr) is formed in the outer edge portion 40 e. With such a through hole 40, the elastic member 3 is less likely to be caught by the outer edge 40e of the through hole 40 during contraction. Therefore, the elastic member 3 is inhibited from being exposed from the through hole 40 to the outside (from one side to the other side in the thickness direction) of the 1 st continuous sheet 2A (non-skin side nonwoven fabric 22).

Here, a method of forming the through hole 40 is briefly described. Fig. 11A to 11C are schematic explanatory views for explaining a conventional method for forming an apertured nonwoven fabric. Fig. 12A to 12C are schematic explanatory views for explaining a method of forming an apertured nonwoven fabric according to the present embodiment.

Conventionally, when forming holes (through holes) in a nonwoven fabric, a common method is to sandwich the nonwoven fabric from both sides in the thickness direction by needle-like pin portions for forming holes in the nonwoven fabric and groove portions into which the pin portions are inserted. In fig. 11A, pin portions 141 and pin support bases 142 that support the pin portions are provided on the upper side in the thickness direction of the nonwoven fabric, and substantially trapezoidal groove portions 145 are provided on the lower side in the thickness direction of the nonwoven fabric. In this case, the pin portion 141 may be heated to a predetermined temperature or heated air may be pressurized and fed from a blower connected to the groove portion 145 in order to soften the fibers of the nonwoven fabric.

Then, as shown in fig. 11B, the pin portions 141 and the pin support base 142 are moved downward and inserted into the groove portions 145, and the pin portions 141 form openings in the nonwoven fabric. At this time, although the nonwoven fabric has a hole in the portion abutting on the distal end portion of the pin portion 141, the fiber is compressed in the portion sandwiched between the pin support base 142 and the groove portion 145, and a protruding portion (burr) protruding downward in the thickness direction is formed at the outer edge portion of the hole. Then, as shown in fig. 11C, the pin portion 141 and the pin support base 142 are moved upward, and the pin portion 141 having penetrated the nonwoven fabric is pulled out. At this time, since the fibers are compressed by the projections (burrs) formed on the outer edge of the hole, the shape of the hole and the outer edge thereof is easily maintained when the pin portion 141 is pulled out. Therefore, in the perforated nonwoven fabric formed by the conventional method, the protruding portions (burrs) are likely to remain on the outer edge portions of the perforations.

In contrast, in the present embodiment, the through-hole 40 is formed by sandwiching the nonwoven fabric from both sides in the thickness direction by the pin portion 143 formed of needles or the like having the same thickness (diameter) and the cylindrical groove portion 146 having a diameter substantially equal to the diameter of the pin portion 143 into which the pin portion 143 is inserted. Specifically, the through-holes 40 are formed by providing the pin portions 143 on the upper side in the thickness direction of the 1 st continuous body 2A (non-skin-side nonwoven fabric 22), providing the groove portions 146 on the lower side in the thickness direction of the 1 st continuous body 2A (see fig. 12A), and moving the pin portions 143 downward to be inserted into the groove portions 146 (see fig. 12B). In the present embodiment, since the gap in the radial direction between the pin portion 143 and the groove portion 146 is small, about 0.3mm to 0.5mm, in fig. 12B, when the 1 st continuous sheet 2A is sandwiched between the upper end edge of the groove portion 146 and the pin portion 143, the fibers of the nonwoven fabric are cut and the through holes 40 are formed. That is, when the pin portion 143 is inserted into the groove portion 146, the outer edge portion of the through hole 40 is less likely to be compressed in the thickness direction. Therefore, in the present embodiment, the protruding portion (burr) at the outer edge portion of the opening as shown in fig. 11B is not easily formed. Then, the pin 143 is moved upward, and the pin 143 penetrating the 1 st continuous sheet 2A is pulled out (see fig. 12C).

With this arrangement, the protrusion of the through-hole 40 in the thickness direction at the outer edge 40e can be suppressed to be low, and an apertured nonwoven fabric without large protrusions (burrs) can be formed. In the through-hole 40 formed by the above-described method, the maximum value of the height h40e of the outer edge portion 40e protruding in the thickness direction as shown in fig. 10 is 0.2 mm. That is, the protrusion height h40e in the thickness direction of the outer edge 40e of the through-hole 40 formed in the 1 st continuous sheet 2A (non-skin side nonwoven fabric 22) according to the present embodiment is suppressed to 0.2mm or less (h40 e. ltoreq.0.2 mm). When the protrusion height h40e is 0.2mm or less, the elastic member 3 can be effectively prevented from being exposed from the through hole 40 as described in fig. 7.

Further, by adjusting the size of the diameter D40 of the through hole 40, the elastic member 3 can be prevented from being exposed from the through hole 40. For example, by setting the magnitude relationship between the diameter D40 of the through hole 40 and the diameter D3 of the elastic member 3 within a predetermined range, exposure of the elastic member 3 can be easily suppressed. Specifically, when the elastic member 3 is exposed from the through hole 40, the elastic member 3 in the middle of the reverse movement is deformed into an Ω shape as shown in fig. 7B and is exposed from the through hole 40. Therefore, when the diameter D40 of the through hole 40 is smaller than the diameters 2 × D3 of the two elastic members 3 (D40<2 × D3), the phenomenon in which the Ω -shaped elastic member 3 passes through the through hole 40 is less likely to occur, and therefore, exposure of the elastic member 3 can be suppressed with high accuracy. The through hole 40 is not necessarily formed in a perfect circle, and may be formed in an ellipse or the like. The sizes of the through

holes

40 and 40 … … may be different from each other. In this case, the diameter D40 is an average value of the diameters of the through holes 40. The diameter d3 of the elastic member 3 represents the diameter of the elastic member 3 in the natural state (non-stretched state).

However, since the through holes 40 function as ventilation holes in the diaper 1, the diameter D40 of the through holes 40 is preferably as large as possible to maintain the ventilation. When the sheet member 2 is manufactured by the manufacturing method of the present embodiment, the rate of occurrence of exposure of the elastic member 3 when the diameter D40 of the through hole 40 is 4 times the diameter D3 of the elastic member 3 is 20% or more. Here, the "occurrence rate of exposure of the elastic member 3" represents a ratio of the number of the abdomen side portions 20 where exposure of the elastic member 3 is seen when 100 abdomen side portions 20 (diaper 1) are manufactured. In this case, since the package in which the right and left diapers 1 of 10 to 20 are packaged includes a plurality of diapers 1 in which the elastic members 3 are exposed, there is a possibility that a user who purchases the package may be disturbed.

On the other hand, the occurrence rate of exposure of the elastic member 3 when the diameter D40 of the through hole 40 is 3 times the diameter D3 of the elastic member 3 is 1% or less. In this case, the diaper 1 with the exposed elastic member 3 is less likely to be contained in a package in which about 10 to 20 diapers 1 are packaged, and it is possible to make the user less likely to be anxious.

Therefore, by setting the diameter D40 of the through-hole 40 to be 3 × D3 or less (D40 ≦ 3 × D3) of the diameter of 3 elastic members 3, it is possible to provide the diaper 1 in which good air permeability is ensured and the elastic members 3 are not easily exposed from the through-hole 40.

Further, the diameter D40 of the through hole 40 may be different on one side and the other side in the thickness direction. Specifically, the diameter D40B on the other side (non-skin side) in the thickness direction may be made larger than the diameter D40A on the one side (skin side) in the thickness direction (D40A < D40B). Fig. 13 is a schematic cross-sectional view showing a case where the diameter of the through-hole 40 is different between one side and the other side in the thickness direction.

As shown in fig. 13, by making the diameter D40A of the through hole 40 on one side (skin side) in the thickness direction as small as possible, the elastic member 3 that tends to be inhibited from moving in the reverse direction as described above is exposed from the through hole 40. On the other hand, by increasing the diameter D40B of the through-hole 40 on the other side (non-skin side) in the thickness direction, the through-hole 40 visible on the surface of the non-skin side is easily made conspicuous in the torso-surrounding portion 20 of the diaper 1. Thus, the user can easily recognize that the body surrounding portion 20 has good air permeability.

When forming such through-holes 40 in the 1 st continuous sheet 2A (non-skin side nonwoven fabric 22), the pin portions 143 described with reference to fig. 12 are preferably heated to form holes under a predetermined temperature condition. By using the heated pin portions 143, the through-holes 40 can be formed while heating the 1 st continuous sheet 2A. The temperature of the heated pin portion 143 is preferably not lower than the softening point of the thermoplastic resin fibers contained in the 1 st continuous sheet 2A but lower than the melting point of the thermoplastic resin fibers. By setting the temperature of the heated pin portions 143 to be lower than the melting point, thermal damage to the 1 st continuous body 2A due to the heated pin portions 143 can be suppressed, and by setting the temperature of the heated pin portions 143 to be equal to or higher than the softening point, fibers can be made soft and frictional resistance when the through holes 40 are formed in the 1 st continuous body 2A can be reduced. Further, the thermoplastic resin fibers may be set to a temperature at which they are not hardened. By setting the temperature of the thermoplastic resin fibers to a temperature at which the thermoplastic resin fibers are not hardened, the possibility that the nonwoven fabric is hardened at the outer edge portion 40e of the through hole 40 can be reduced. In addition, the softening point can be measured following jis k7196 (softening temperature test method using thermo-mechanical analysis of thermoplastic plastic films and sheets). Thus, the pin portion 143 can be pulled out after the pin portion 143 is pushed in while the 1 st continuous body 2A is heated, and therefore the pin portion 143 can be easily inserted into the 1 st continuous body 2A softened by heating, and the hole shape of the formed through hole 40 can be easily maintained.

Further, the temperature of the pin portion 143 is preferably a temperature close to the softening point of the melting point of the thermoplastic resin fibers contained in the 1 st continuous sheet 2A. That is, the heating temperature of the pin portion 143 is preferably as low as possible within the temperature range between the melting point and the softening point of the thermoplastic resin fibers. In the continuous body 2A of the 1 st sheet of the present embodiment, the through-hole 40 is formed by heating the pin portion 143 to about 120 to 135 ℃. When the temperature of the softened thermoplastic fibers is lowered by lowering the heating temperature as much as possible in this way, the fibers in the opening portion are likely to shrink, and the diameter D40 of the through-hole 40 is likely to be small. Further, when the pin portion 143 is pulled out on the other side (non-skin side) in the thickness direction as shown in fig. 12C, the temperature of one side (skin side) in the thickness direction of the 1 st continuous sheet 2A tends to decrease first, and therefore, the fibers tend to be more easily shrunk on the skin side of the through-hole 40. Therefore, the diameter D40A of the through-hole 40 on one side (skin side) in the thickness direction is liable to be smaller than the diameter D40B of the through-hole 40 on the other side (non-skin side) in the thickness direction. Thereby, the through-hole 40 having the shape as shown in fig. 13 is formed.

In the through-hole 40 formed in this manner, the ratio of the non-melted portion of the thermoplastic fiber is greater than the ratio of the melted portion at the outer edge portion 40e of the through-hole 40. In the non-melted portion of the thermoplastic fiber, the flexibility of the fiber is easily maintained, and the rigidity is not easily increased, so that the higher the proportion of the non-melted portion is, the more the rigidity at the outer edge portion 40e of the through hole 40 can be reduced. Therefore, the elastic member 3 is less likely to be caught by the outer edge portion 40e during the reverse movement, and the elastic member 3 is less likely to be exposed from the through hole 40. In addition, since the softness of the non-skin side nonwoven fabric 22 in the region where the through-holes 40 are formed is easily maintained, a good feel of the diaper 1 can be achieved.

Embodiment 2

In embodiment 2, a tape-type disposable diaper 5 (hereinafter also referred to as "diaper 5") is described as an absorbent article.

Basic structure of tape-type disposable diaper 5

Fig. 14 is a plan view of the diaper 5 of embodiment 2 in an unfolded and extended state. Fig. 15 is a sectional view taken along line B-B shown in fig. 14. The diaper 5 has a longitudinal direction and a transverse direction orthogonal to each other, and has a back-side body surrounding region 5A, a crotch region 5B, and an abdomen-side body surrounding region 5C arranged in the longitudinal direction. The longitudinal direction of the diaper 5 is a direction corresponding to the vertical direction (longitudinal direction) of the diaper 1, and the lateral direction of the diaper 5 is a direction corresponding to the lateral direction (width direction) of the diaper 1. As shown in fig. 15, the direction in which the materials constituting the diaper 5 are laminated is referred to as the thickness direction. In the thickness direction, the side in contact with the wearer is referred to as the skin side, and the opposite side to the side is referred to as the non-skin side.

As shown in fig. 14 and 15, the diaper 5 includes an absorbent body 11 for absorbing excrement, a liquid-permeable skin side sheet 12 positioned on the skin side of the absorbent body 11, a liquid-permeable intermediate sheet 13 positioned between the absorbent body 11 and the skin side sheet 12, a liquid-impermeable leakage-preventing sheet 14 positioned on the non-skin side of the absorbent body 11, an outer sheet 15 positioned on the non-skin side of the leakage-preventing sheet 14, and a pair of side sheets 16 provided on both lateral side portions of the skin side sheet 12. The pair of fastening bands 17 extend laterally outward from the back-side torso-surrounding region 5A. Leg hole stretchable members (e.g., rubber threads) stretchable in the longitudinal direction are disposed on both lateral side portions of the diaper 5, and the diaper 5 is attached to the leg hole of the wearer. Further, a pair of leakage preventing walls 18 standing up toward the skin side are provided on both lateral side portions of the absorbent body 11. The structure of the absorbent body 11 in the diaper 5 is substantially the same as that of the absorbent body 11 of embodiment 1.

In the crotch region 5B, a plurality of crotch region gather elastic members 35 such as rubber strings are attached between the leakage barrier sheet 14 and the outer covering sheet 15 in the thickness direction in a longitudinally extended state. The stretchability exhibited by the crotch region gather elastic member 35 causes a force that pushes the absorbent body 11 from the non-skin side to the skin side to act on the wearer's crotch portion when the diaper 5 is worn. This makes it easy for the absorbent body 11 to come into close contact with the skin of the wearer in the crotch portion, improves the fit of the crotch portion, and makes it easy to suppress leakage of excrement.

In the diaper 5 according to embodiment 2, the outer sheet 15 is a perforated nonwoven fabric similar to the non-skin side nonwoven fabric 22 according to embodiment 1, and a plurality of through holes 40 penetrating the outer sheet 15 in the thickness direction are formed in the surface of the outer sheet 15. The through-hole 40 provided in the exterior sheet 15 of embodiment 2 has a structure substantially similar to the through-hole 40 of embodiment 1.

Method for manufacturing sheet member 6

Of the members constituting the diaper 5, the leakproof sheet 14, the outer sheet 15 and the crotch-region gather elastic member 35 provided between the leakproof sheet 14 and the outer sheet 15, which are laminated in the thickness direction, correspond to the outer package of the diaper 5. Hereinafter, a method for manufacturing the sheet member 6 will be described with the outer package as the "sheet member 6" (see fig. 15).

In embodiment 2, the sheet member 6 is a sheet-like member in which a plurality of leak-proof sheets 14 and an outer sheet 15 are connected in series in a predetermined direction (a direction corresponding to the longitudinal direction of fig. 14). In the method of manufacturing the sheet member 6, a continuous body of nonwoven fabric corresponding to the exterior sheet 15 provided with the plurality of through

holes

40, 40 … … is referred to as the 1 st continuous body 6A. The continuous body of the liquid-impermeable sheet corresponding to the leakproof sheet 14 is referred to as the 2 nd continuous body 6B, and the elastic member corresponding to the crotch region gather elastic member 35 is referred to as the elastic member 7.

Fig. 16 is a schematic side view illustrating a manufacturing apparatus 200 for manufacturing the sheet member 6. The basic configuration of the manufacturing apparatus 200 is substantially the same as that of the manufacturing apparatus 100 according to embodiment 1, and includes a conveying mechanism 210, a joining region forming mechanism 220, and an elastic member cutting mechanism 230. Then, the same steps as those of the sheet member 2 are performed using the manufacturing apparatus 200 (S101 to S103), thereby manufacturing the sheet member 6 (see fig. 5).

First, in the conveying step (S101), the 1 st continuous body 6A is conveyed from the upstream side to the downstream side in the conveying direction at a predetermined conveying speed by the conveying mechanism 210 including a plurality of conveying rollers. In the manufacturing apparatus 200, the conveyance direction is a direction along the longitudinal direction of the diaper 5. Similarly, the 2 nd continuous body 6B and the elastic member 7 are conveyed from the upstream side to the downstream side in the conveying direction at a predetermined conveying speed by the conveying mechanism 210.

Next, a joining region forming step of forming a plurality of joining

regions

50 and 50 … … for attaching the elastic member 7 to the 1 st continuous piece 6A and the 2 nd continuous piece 6B is performed (S102). As shown in fig. 16, the 1 st continuous body 6A and the 2 nd continuous body 6B are conveyed in a stacked manner in the thickness direction. The elastic member 7 is arranged between the 1 st continuous piece 6A and the 2 nd continuous piece 6B in the thickness direction thereof in a state of being elongated in the conveyance direction at a predetermined elongation ratio, and the elastic member 7 is attached so as to be sandwiched between the 1 st continuous piece 6A and the 2 nd continuous piece 6B via the joining region 50. The method of forming the junction region 50 is substantially the same as that of embodiment 1.

Fig. 17 is a schematic plan view showing an example of the arrangement of the bonding region 50. The sheet cutting position EC indicated by a broken line in fig. 17 indicates a position at which the sheet member 6 is cut in a subsequent step (step of manufacturing the diaper 5 using the sheet member 6).

In embodiment 2, the joining region 50 is formed at 1 or more positions on both sides of the sheet cutting position EC in the conveying direction. In the example of fig. 17, a 1 st bonding region 511 is formed on the upstream side in the conveying direction and a 2 nd bonding region 512 is formed on the downstream side in the conveying direction with respect to the sheet cutting position EC. The elastic member 7 in an expanded state in the conveyance direction is attached between the 1 st continuous sheet 6A and the 2 nd continuous sheet 6B by the above-described joining region 50. Further, as in embodiment 1, an adhesive may be provided between the 1 st bonding region 511 and the 2 nd bonding region 512 in the conveying direction.

Next, an elastic member cutting step (S103) of cutting the elastic member 7 in the state of being stretched in the conveyance direction between the two joining

regions

50, 50 adjacent to each other in the conveyance direction is performed. The elastic member is cut by an elastic member cutting mechanism 230 including a pair of cutter rollers 231 and an anvil roller 232. In fig. 17, the elastic member 7 in an extended state is cut at an elastic member cutting position CP between the 1 st joining region 511 and the 2 nd joining region 512 adjacent to each other in the conveying direction. The cut elastic member 7 moves in the opposite directions from the elastic member cutting position CP toward the upstream side and the downstream side in the conveying direction, and the stretchability due to the elastic member 7 disappears in the region between the 1 st joining region 511 and the 2 nd joining region 512. That is, stretchability is imparted to only a part of the crotch region 5B of the diaper 5.

In the elastic member cutting step (S103), similarly to embodiment 1, by appropriately adjusting the elastic member cutting position CP, the elastic member 7 which moves in the reverse direction (contracts) can be prevented from being exposed from the through hole 40 provided in the 1 st continuous sheet 6A. Specifically, the elastic member 7 is cut at a position closer to the 1 st joining region 511 than the 2 nd joining region 512 in the conveying direction. In the case of fig. 17, it is desirable that: when the intermediate position in the conveying direction between the 1 st joining region 511 and the 2 nd joining region 512 is C51, the elastic member cutting position CP is set to a position upstream in the conveying direction from the intermediate position C51.

In such an arrangement, as described with reference to fig. 8, the amount of contraction per unit time of the elastic member 7 can be made relatively small. That is, the speed V71 at which the elastic member 7 cut at the elastic member cutting position CP contracts toward the upstream side in the conveying direction is set to be lower than the speed V72 at which the elastic member 7 contracts toward the downstream side in the conveying direction with respect to the sheet member 6 conveyed at the predetermined conveying speed V2 in the conveying direction. Thus, the contraction force of the elastic member 7 can be reduced as a whole. This makes it difficult for the elastic member 7 to catch on the outer edge 40e of the through hole 40 during the reverse movement, and the elastic member 7 is easily prevented from coming out of the through hole 40.

The portion in which the stretchability of the elastic member 7 (crotch region gather elastic member 35) in the conveying direction acts is also referred to as an "effective length portion" of the elastic member. Further, as shown in fig. 14, the distance d35f between the abdomen-side end of the diaper 5 and the abdomen-side end of the effective length portion of the crotch-region gather elastic member 35 is larger than the distance d35b between the back-side end of the diaper 5 and the back-side end of the effective length portion of the crotch-region gather elastic member 35 in the longitudinal direction. That is, the effective length portion of the crotch region gather elastic member 35 is disposed further to the center back portion side in the longitudinal direction of the diaper 5. Therefore, when the diaper 5 is worn, the absorbent body 11 is easily fitted to the wearer's body on the hip side, and leakage of excretions is easily suppressed. In the case of such a configuration, the elastic member 7 (crotch-region gather elastic member 35) is cut in the back-side body surrounding region 5A (see fig. 17), whereby the contraction force of the elastic member 7 can be suppressed to be small. Therefore, the position adjustment of the elastic member cutting position CP is easy, and the diaper 5 in which the crotch region gather elastic member 35 is not easily exposed from the through hole 40 can be easily realized.

Modification of the joining region 50

In the above-described embodiment, the bonding region 50 is formed using a bonding member such as a hot melt adhesive, but the method of forming the bonding region 50 is not limited thereto. The joining region 50 may be formed by a welding method such as ultrasonic welding. Since ultrasonic welding is a known technique, the description of ultrasonic welding will be omitted in this specification.

Fig. 18 is a schematic plan view illustrating a modification of the joining region 50. Fig. 18 is a diagram showing a modification of the joint region described with reference to fig. 6 of embodiment 1. In the present modification, the welded region 50 is formed by a plurality of welded portions 52, 52 that are arranged in a dispersed manner in the conveying direction and in the direction (CD direction) orthogonal to the conveying direction. Each of the welded portions 52 is formed into a substantially rectangular shape by ultrasonic welding, the 1 st continuous sheet 2A and the 2 nd continuous sheet 2B are joined in the thickness direction, and the elastic member 3 is sandwiched from both sides in the CD direction by 1 pair of the welded portion pairs 52S adjacent to each other in the CD direction, thereby attaching the elastic member 3 to the sheet member 2.

Fig. 19A and 19B are explanatory views of a function of attaching the elastic member 3 by the pair of fusion-bonded parts 52S, and are schematic enlarged views of a part C in fig. 18. As shown in fig. 19A, the pair of fusion-bonded portions 52 and 52 constituting the fusion-bonded portion pair 52S are arranged with a gap GH50 therebetween in the CD direction. The size of the gap GH50 is set to be the same as the diameter d3t of the elastic member 3 in the state of being elongated to a predetermined elongation ratio or slightly larger than the diameter d3t (GH50 ≧ d3 t). That is, the elastic member 3 in the stretched state is disposed between the pair of fusion-bonded portions 52S in the CD direction.

When the elastic member 3 is relaxed from the extended state from this state, as shown in fig. 19B, the elastic member 3 contracts in the conveyance direction and expands in the CD direction, and the diameter d3 in the natural state becomes larger than the interval GH50 in the CD direction of the pair of fusion-spliced portions 52S (d3> GH 50). This brings the elastic member 3 into a state sandwiched in the CD direction by the welded portions 52, 52. As a result, the elastic member 3 is attached to the sheet member 2.

In the underpants type diaper 1 shown in fig. 1, the gathered gather elastic member 32 (elastic member 3) is in a natural state after being relaxed from the above-described stretched state. In addition, in the diaper 1 in the pants-type state, both side portions in the right and left direction of the abdomen side portion 20 (back side portion 30) are joined by welding or the like, and therefore, even if the abdomen side portion 20 is stretched in the right and left direction when the diaper 1 is put on, the gather elastic member 32 does not come off the abdomen side portion 20.

The joint region 50 in the diaper 5 according to embodiment 2 can also be formed by the pair of fusion-bonded parts 52S as described above.

Other embodiments

The embodiments of the present invention have been described above, and the above embodiments are not intended to limit the present invention in order to facilitate understanding of the present invention. It is needless to say that changes and improvements can be made without departing from the gist of the present invention, and the present invention includes equivalents of the changes and improvements.

Description of the reference numerals

1. Diapers (embodiment 1) (underpants type disposable diapers, absorbent articles); 2. a sheet member (embodiment 1); 2A, 1 st continuous body (non-skin side nonwoven fabric); 2B, the 2 nd continuous body (skin side nonwoven fabric); 3. elastic members (fit-gather elastic members); 5. a diaper (embodiment 2) (tape-type disposable diaper, absorbent article); 6. a sheet member (embodiment 2); 6A, No. 1 continuous body (outer packaging sheet); 6B, a 2 nd continuous sheet (liquid-impermeable sheet); 7. an elastic member (crotch region gather elastic member); 10. an absorbent main body; 11. an absorbent body; 12. a skin side panel; 13. an intermediate sheet; 14. a leakproof sheet; 15. an outer packaging sheet; 16. a side sheet; 17. a fastening tape; 18. a leakage preventing wall portion; 20. the abdominal side; 21. a skin-side nonwoven fabric; 22. a non-skin side nonwoven fabric; 23. attaching a corrugated elastic member; 24. covering non-woven fabrics; 30. a back side portion; 31. a skin-side nonwoven fabric; 32. a non-skin side nonwoven fabric; 33. attaching a corrugated elastic member; 34. covering non-woven fabrics; 35. a crotch region gathered elastic member; 40. a through hole; 40e, an outer edge portion; 50. a bonding region; 501. the 1 st bonding region; 502. a 2 nd joining region; 511. the 1 st bonding region; 512. a 2 nd joining region; 52. a fusion part; 52S, a welding part pair; 100. a manufacturing apparatus (embodiment 1); 110. a conveying mechanism; 120. a bonding region forming mechanism; 122. a sheet member adhesive application section; 123. an elastic member adhesive application section; 130. an elastic member cutting mechanism; 131. a cutting roller; 132. an anvil roll; 141. a pin portion; 142. a pin support base; 143. a pin portion; 145. a groove part; 146. a groove part; 200. a manufacturing apparatus (embodiment 2); 210. a conveying mechanism; 220. a bonding region forming mechanism; 222. a sheet member adhesive application section; 223. an elastic member adhesive application section; 230. an elastic member cutting mechanism; 231. a cutting roller; 232. an anvil roll.

Claims

1. A method for manufacturing a sheet member for an absorbent article, characterized in that,

the method for manufacturing the sheet member for the absorbent article comprises a conveying step, a bonding region forming step and an elastic member cutting step,

the conveying step conveys the 1 st continuous body and the 2 nd continuous body which are provided with a plurality of through holes respectively,

the joining region forming step forms a plurality of joining regions for attaching an elastic member in a state of being stretched in a conveying direction of the 1 st continuous sheet or the 2 nd continuous sheet between the 1 st continuous sheet and the 2 nd continuous sheet stacked on one side in a thickness direction of the 1 st continuous sheet,

the elastic member cutting step cuts the elastic member in an extended state between two of the joining regions adjacent to each other in the conveying direction, and contracts the cut elastic member in the conveying direction so as not to be exposed from the through hole to the other side in the thickness direction of the 1 st continuous sheet.

2. The method for manufacturing a sheet member for an absorbent article according to claim 1,

the joining region has a 1 st joining region and a 2 nd joining region, the 2 nd joining region and the 1 st joining region being adjacent to each other on a downstream side in the conveying direction,

in the cutting step, the elastic member is cut at a position closer to the 1 st bonding region than the 2 nd bonding region in the conveying direction.

3. The method for manufacturing a sheet member for an absorbent article according to claim 1 or 2,

the height of the portion of the through-hole, which protrudes in the thickness direction at the outer edge portion, is 0.2mm or less.

4. The method for manufacturing a sheet member for an absorbent article according to claim 1 or 2,

the diameter of the through hole is 3 times or less of the diameter of the elastic member.

5. The method for manufacturing a sheet member for an absorbent article according to claim 4,

the diameter of the through hole is less than 2 times the diameter of the elastic member.

6. The method for manufacturing a sheet member for an absorbent article according to claim 1 or 2,

a diameter of the through hole at the one side in the thickness direction is smaller than a diameter of the through hole at the other side in the thickness direction.

7. The method for manufacturing a sheet member for an absorbent article according to any one of claims 1 to 6,

forming the through hole by passing a pin from one side to the other side in the thickness direction of the 1 st continuous sheet,

when the through-holes are formed, the pins are heated to a temperature of not less than the softening point but less than the melting point of the thermoplastic fibers contained in the 1 st continuous sheet.

8. The method for manufacturing a sheet member for an absorbent article according to claim 7,

in the formation of the through-hole, the pin is heated to a temperature close to the softening point than the melting point of the thermoplastic fiber contained in the 1 st continuous sheet.

9. The method for manufacturing a sheet member for an absorbent article according to any one of claims 1 to 8,

an adhesive is provided between the 1 st bonding area and the 2 nd bonding area in the conveying direction.

10. The method for manufacturing a sheet member for an absorbent article according to any one of claims 1 to 9,

the sheet member for an absorbent article is a body-surrounding part member of a pants-type disposable diaper,

the elastic member is a bonded-wrinkle elastic member that imparts stretchability to the body surrounding part member,

cutting at least a part of the bonded gathered elastic member by the elastic member cutting step.

11. The method for manufacturing a sheet member for an absorbent article according to any one of claims 1 to 9,

the sheet member for an absorbent article is an outer package of a tape-type disposable diaper,

the elastic member is a crotch region gather elastic member which imparts stretchability to the crotch region of the outer cover,

cutting at least a portion of the crotch region gather elastic member by the elastic member cutting process.

12. An absorbent article having a vertical direction and a horizontal direction intersecting each other,

the absorbent article includes a sheet member having a 1 st sheet member, a 2 nd sheet member, an elastic member, and a joining portion,

the 1 st sheet member is provided with a plurality of through holes on the surface,

the 2 nd sheet member is laminated on the skin side of the 1 st sheet member,

the elastic member is provided between the 1 st sheet member and the 2 nd sheet member in an elongated state in the left-right direction,

a plurality of joining portions for attaching the elastic member to the 1 st sheet member and the 2 nd sheet member,

it is characterized in that the preparation method is characterized in that,

the elastic member cut between two of the joining portions adjacent to each other in the left-right direction contracts in the left-right direction so as not to be exposed from the through hole to the non-skin side of the 1 st sheet member.

13. The absorbent article of claim 12,

a plurality of elastic members are provided at intervals in the vertical direction,

the plurality of elastic members are cut at positions different from each other in the left-right direction.

14. The absorbent article according to claim 12 or 13,

the height of the portion of the outer edge of the through hole protruding toward the skin side is 0.2mm or less.

15. The absorbent article according to claim 12 or 13,

the diameter of the through hole is 3 times or less the diameter of the elastic member.

16. The absorbent article of claim 15,

17. The absorbent article according to claim 12 or 13,

the diameter of the through hole on the skin side is smaller than the diameter of the through hole on the non-skin side.

18. The absorbent article according to any one of claims 12 to 17,

the 1 st sheet member is a nonwoven fabric comprising thermoplastic fibers,

the proportion of the non-melted portion of the thermoplastic fiber is greater than the proportion of the melted portion of the thermoplastic fiber at the outer edge portion of the through hole.

19. The absorbent article according to any one of claims 12 to 18,

the sheet member is a body-surrounding part member of a pants-type disposable diaper,

at least a part of the bonded-wrinkle elastic member is cut at a predetermined position in the left-right direction.

20. The absorbent article according to any one of claims 12 to 18,

the sheet member is an outer package of a tape-type disposable diaper,

at least a part of the crotch region gather elastic member is cut at a predetermined position in the vertical direction.

21. The absorbent article of claim 20,

the absorbent article has a longitudinal direction along the up-down direction in an unfolded state,

in the longitudinal direction, the distance between the abdomen-side end of the absorbent article in the unfolded state and the abdomen-side end of the portion where the stretchability of the crotch-region gather elastic member acts is larger than the distance between the back-side end of the absorbent article in the unfolded state and the back-side end of the portion where the stretchability of the crotch-region gather elastic member acts.