Patent Application
20170007466
The invention relates to a method for manufacturing an absorbent article.
In a manufacturing line for absorbent articles such as a disposable diaper, the following method is commonly used for manufacturing pull-on diapers: the end sections of the continuous sheet in the transverse direction are folded to be layered on a ventral part and on a dorsal part while the continuous sheet is transported in the transport direction, the continuous sheet being to be an exterior material of a disposable diaper, the transport direction being a direction in which the continuous sheet continues; then, both end sections of the continuous sheet are each joined; and thereafter a single-cut piece is cut and separates from the continuous sheet. As methods for joining the transverse end sections of the ventral part of a diaper to the transverse end sections of the dorsal part, methods by welding such as ultrasonic sealing or heat sealing are widely known. For example, in Patent Literature 1, a plurality of band-like sheets which constitute an exterior material are joined with adhesive while extended elastic members are sandwiched between the band-like sheets. And, the ventral part and the dorsal part are joined by welding the sheets on the adhesive-applied area, and as a result, a diaper is formed. In addition, elastic force of elastic members is provided to a diaper, and this allows a user to feel good body fit.
[Patent Literature 1] Japanese Patent Application Laid-open Publication No. 2013-126528
In some cases, welding on an adhesive-applied area of the sheets, as in Patent Literature 1, causes some problems. For example, due to the oil contained in adhesive, there is a possibility that welding strength of ultrasonic sealing is not sufficient and that adhesive which has put on a welding device stops continuous production of diapers. These troubles can be prevented if adhesive is not applied to areas to be welded. But, in this case, elastic members do not adhere to the exterior material of a diaper on the areas to which adhesive is not applied. Accordingly, on the areas, stretching-and-contraction force is not exerted. When a diaper in such a state is cut and separated from the continuous sheet, the elastic members are cut on both transverse end sections of the diaper, and the elastic members contract from both transverse end sections towards the transverse center of the diaper. On the other hand, stretching-and-contraction force due to elastic members is not exerted on areas of both transverse end sections on which adhesive is not applied, and therefore the exterior material does not contract. That is, only the elastic members contract, but the exterior material does not contract. Accordingly, the exterior material looks extending transversely outwardly beyond both transverse end sections, and this may deteriorate the appearance of a diaper.
In view of the problem described above, it is an advantage of the invention to provide a pull-on diaper in which the welding strength of the side parts thereof is sufficient and whose appearance is good.
An aspect of the invention to achieve the above advantage is
a method for continuously manufacturing an absorbent article,
Other features of this invention will become apparent from the description in this specification and the attached drawings.
According to the invention, it is possible to provide a pull-on diaper in which the welding strength of the side parts thereof is sufficient and whose appearance is good.
At least the following matters will be made clear by the description in the present specification and the accompanying drawings.
A method for continuously manufacturing an absorbent article,
With such a method for manufacturing an absorbent article, it is possible to manufacture a pull-on diaper in which the welding strength of the side parts thereof is sufficient and whose appearance is good.
In such a method for manufacturing an absorbent article, it is preferable that the second area does not overlap the first area within at least a partial area along the transport direction.
With such a method for manufacturing an absorbent article, an area in which the adhesion area and the welded section do not overlap is formed. This can prevent the following phenomena: welding strength of the welded section is insufficient due to the oil of adhesive which forms the adhesion area; and the number of maintenance operations of a welding device increases due to putting of adhesive.
In such a method for manufacturing an absorbent article, it is preferable that the adhesive is not put on the second area.
With such a method for manufacturing an absorbent article, the welded section can be formed an area on which adhesive is not put. This can achieve sufficient welding strength of the welded section. In addition, since the elastic members do not adhere to the substrate of a diaper in the area, the elastic members are more likely to contract. The contraction of the elastic members allows the substrate to shrink more easily, and this reduces the width of side areas of a pull-on diaper, which extend beyond both transverse end sections. This can improve the appearance of a diaper 1.
In such a method for manufacturing an absorbent article, it is preferable that the adhesive is put on the second area, and that an amount per unit area of the adhesive that has been put on the second area is smaller than an amount per unit area of the adhesive that has been put on the first area.
With such a method for manufacturing an absorbent article, the welded section can be formed on an area on which a small amount of adhesive is put (having a small basis weight). This makes it easier to ensure sufficient welding strength of the welded section. In addition, the elastic members are less likely to adhere to the substrate on the second area. Accordingly, the elastic members and the substrate become more likely to shrink, and this reduces the width of side areas of a pull-on diaper, which extend beyond both transverse end sections. This can improve the appearance of a diaper 1.
In such a method for manufacturing an absorbent article, it is preferable that the adhesive is put on the second area, and that an amount per unit area of the adhesive which is put on the first area and the second area is determined so that welding strength in a case in which the lower bandlike member and the upper bandlike member are welded in the second area on which the adhesive is put is larger than welding strength in a case in which the lower bandlike member and the upper bandlike member are welded in the first area on which the adhesive is put.
With such a method for manufacturing an absorbent article, even if adhesive is put on the second area, it is easy to ensure sufficient strength of the welded section formed on the second area. In addition, the elastic members are less likely to adhere to the substrate on the second area. Accordingly, the elastic members and the substrate become more likely to shrink, and this reduces the width of side areas of a pull-on diaper, which extend beyond both transverse end sections. This can improve the appearance of a diaper 1.
In such a method for manufacturing an absorbent article, it is preferable that an amount per unit area of the adhesive that has been put on the second area is smaller than an amount per unit area of the adhesive that has been put on the first area.
With such a method for manufacturing an absorbent article, the welded section can be formed on an area on which a small amount of adhesive is put (having a small basis weight). This makes it easier to ensure sufficient welding strength of the welded section. In addition, the elastic members are less likely to adhere to the substrate on the second area. Accordingly, the elastic members and the substrate become more likely to shrink, and this reduces the width of side areas of a pull-on diaper, which extend beyond both transverse end sections. This can improve the appearance of a diaper 1.
In such a method for manufacturing an absorbent article, it is preferable that a plurality of the welded sections are formed at intervals along the intersecting direction, and that a distance between two welded sections that are formed adjacent in the intersecting direction is larger than a diameter of the elastic member.
With such a method for manufacturing an absorbent article, the elastic members enter between two adjacent welded sections. Accordingly, the welded sections become less likely to be placed on the elastic members, and this makes it easier to ensure sufficient welding strength of the welded sections. In addition, the elastic members are firmly held being sandwiched between the upper bandlike member and the lower bandlike member. Accordingly, problems such as elastic drop-off can become less likely to occur.
In such a method for manufacturing an absorbent article, it is preferable that the process in which the adhesion area is formed is performed by placing the elastic members on at least either one of the lower bandlike member and the upper bandlike member, adhesive being applied to the elastic members on a certain area while the elastic members being stretched in the transport direction.
With such a method for manufacturing an absorbent article, applying the adhesive to the elastic members increase adhesion of the elastic members on the adhesion area compared to the cases where the adhesive is not applied to the elastic members. This makes it easier to prevent problems such as elastic drop-off. Further, the process in which the adhesion area is formed and the process in which the elastic members are placed are simultaneously performed, and this allows the absorbent articles to be efficiently manufactured.
As an example of an absorbent article manufactured in a manufacturing method of the present embodiment, a pull-on disposable diaper (hereinafter referred to as a diaper 1) is employed and the basic configuration thereof will be described first.
As shown in
The lower exterior member 5 and the upper exterior member 7 are flexible stretchable members in the form of sheet, and are made of materials such as nonwoven fabric. As shown in
The exterior member 10 forms the contour of diaper 1 in the spread-out state, and the planar shape thereof is a substantially hourglass shape (see
The absorbent main body 3 is in a substantially rectangular shape when viewed from above. The absorbent main body 3 is placed in the center of the transverse direction, and the lengthwise direction of the absorbent main body 3 is along the longitudinal direction of the diaper 1. The absorbent main body 3 does not have to be in a rectangular shape shown in
On appropriate positions in the exterior member 10, a plurality of the elastic members 8B, 8F, 8L . . . , which are made of rubber thread and the like, are placed between the lower exterior member 5 and the upper exterior member 7. These elastic members 8B, 8F, 8L . . . are for providing stretchability to a diaper 1. For example, in the longitudinal edge sections 10e and 10e of the exterior member 10, a plurality of the waist elastic members 8B and 8B are respectively disposed along the transverse direction; the longitudinal edge sections 10e and 10e are respectively an edge section 10e which forms the waist opening 1hB in the ventral part 10A (corresponding to a waist-circumference edge section) and an edge section 10e which forms the waist opening 1hB in the dorsal part 10C (corresponding to a waist-circumference edge section). These waist elastic members 8B and 8B are stretched in the transverse direction and partial areas thereof adhere and are fixed to the lower exterior member 5 and the upper exterior member 7. And stretchability is thereby provided to the waist opening 1hB, which is composed of the edge sections 10e and 10e. Similarly, a plurality of fitting-gather elastic members 8F, 8F, . . . are disposed along the transverse direction at the position near the center in the longitudinal direction with respect to the positions of the waist elastic members 8B. These fitting-gather elastic members 8F, 8F, . . . are stretched in the transverse direction. And, partial areas of thereof adhere and are fixed to the lower exterior member 5 and the upper exterior member 7. Stretchability in the transverse direction is thereby provided to parts between the waist opening 1hB and the longitudinal center. In addition, a plurality of the leg elastic members 8L, 8L, . . . are respectively disposed of edge sections 10eL and 10eL of the transverse edge sections of the exterior member 10, the edge sections 10eL and 10eL being to form the leg openings 1hL. These leg elastic members 8L, 8L, . . . are stretched, and partial areas of thereof adhere and are fixed to the lower exterior member 5 and the upper exterior member 7. Stretchability is thereby provided to the edge sections 10eL and 10eL, which are to form the leg openings 1hL and 1hL.
A pull-on diaper shown in
<Method for Manufacturing Diaper 1>
A method for manufacturing diapers 1 associated with the present embodiment will be described.
In the manufacturing line of the diaper 1, the substrate of the diapers 1 is transported by a suitable transport mechanism along a certain transport direction at a certain transport speed (S101).
The “substrate of the diapers 1” herein means a band-like member in which a plurality of the lower exterior members 5 (or the upper exterior members 7) shown in
The lower bandlike member 15 is transported in the transport direction in a state where the lower exterior members 5 which are adjacent to each other in the transport direction (the transverse direction) continue on a cutting position CL. The cutting position CL is a reference position when the lower exterior member 5 (the exterior member 10) is cut and separates from the lower bandlike member 15 in the following cutting process (S108). That is, the cutting position CL is a position on which a cutting line is formed, the cutting line being for cutting diapers 1 from the bandlike member into a single piece, and also the cutting position CL is for serving as the end sections 10s of a diaper 1 which is shaped in the form of underpants (see
While the lower bandlike member 15 being transported, the leg openings 1hL are formed. The leg openings 1hL are formed in an area extending in the transport direction and being centered on the cutting position CL, and are each indicated as the edge section 10eL of the exterior member 10 in
Next, adhesion areas are formed by putting adhesive onto certain areas on the lower bandlike member 15 which is being transported in the transport direction (S102).
In adhesion-area forming process (S102), the adhesion areas HMA are formed on the first area by putting adhesive thereon, and the first area is a certain area on the substrate. Specifically speaking, the adhesion areas HMA are formed by applying adhesive to the first area on the surface of the lower bandlike member 15 using an adhesive coater (not shown). Hot-melt type adhesive is used as an example of the adhesive for forming the adhesion areas. As indicated by the hatched area in
Adhesive may be applied onto areas other than the first area. But, it is desirable that adhesive is not applied onto a second area (to be described later), or that an smaller amount per unit area of adhesive is applied onto the second area than that of the first area (to reduce basis weight per unit area). This reason will be described later. In the foregoing description, the adhesion areas HMA are formed on the lower bandlike member 15 by putting adhesive on the lower bandlike member 15. However, the adhesion areas HMA may be formed on the upper bandlike member 17 by putting adhesive on the upper bandlike member 17. Also, the adhesion areas HMA may be formed on both members by putting adhesive on both of the lower bandlike member 15 and the upper bandlike member 17.
After the adhesion areas HMA are formed, the elastic members 8B, 8F, and 8L are placed (S103). As shown in
After the elastic members are placed, the upper bandlike member 17 are stacked on the lower bandlike member 15 and the elastic members 8B, 8F, and 8L which are placed on the lower bandlike member 15 (S104). Then, by pressurizing in the thickness direction so that the upper bandlike member 17 is pressed against the lower bandlike member 15, the upper bandlike member 17 adheres to the lower bandlike member 15 on the adhesion areas HMA. The elastic members 8B, 8F, and 8L are thereby held while being sandwiched in the thickness direction between the lower bandlike member 15 and the upper bandlike member 17, and the exterior members of the diapers 1 are formed. The length of the lower bandlike member 15 in the intersecting direction is longer than the length of the upper bandlike member 17 in the intersecting direction, but this is not shown in
As mentioned above, the elastic members 8B, 8F, and 8L are placed being stretched. And, in this process, these elastic members 8B, 8F, and 8L are sandwiched between and firmly held by the lower bandlike member 15 and the upper bandlike member 17. This allows each of the elastic members 8B, 8F, and 8L to produce stretchability in the lower bandlike member 15 and the upper bandlike member 17. For example, the fitting-gather elastic members 8F can produce stretchability between two adhesion areas HMA which are adjacent in the transport direction. In the present embodiment, since the adhesion areas HMA are formed about the cutting position CL, the fitting-gather elastic members 8F produce stretchability in the transport direction in an area of the pitch P1 between a cutting position CL and an adjacent cutting position CL (more precisely, in an area between the cutting position CL and a position distant x in the transport direction in
Subsequently, the absorbent main body 3 is placed on and joined to the upper side of the upper bandlike member 17 in the thickness direction, the upper bandlike member 17 being stacked on and adhering to the lower bandlike member 15 (S105). Note that the absorbent main body 3 is separately manufactured in a manufacturing line for absorbent main bodies (not shown). As shown in
Subsequently, the lower bandlike member 15 and the upper bandlike member 17 which are stacked are folded on the center in the intersecting direction so that the upper bandlike member 17 is located inside the lower bandlike member 15 (that is, inside the upper bandlike member 17 in the thickness direction) (S106).
Subsequently, the ventral part 10A and the dorsal part 10C which are stacked are welded onto a certain area (S107). A method of the welding is heat welding or ultrasonic welding. In the following description, an example of heat welding will be described.
The welding-and-cutting apparatus 50 includes: an anvil roll 51; a sealing roll 52; a cutter roll 53; and transportation-assisting rolls 54. The anvil roll 51 is a drum-like rotating body, and has an sucking mechanism (not shown) on the circumferential surface thereof. The anvil roll 51 rotates while the upper bandlike member 17 and the lower bandlike member 15 are sucked on and fixed to the circumferential surface thereof, and thereby the bandlike members 15 and 17 are transported in the rotating direction. On the circumferential surface of the anvil roll 51, a plurality of anvil brocks 511 are provided. Each of the anvil brocks 511 is a member elongated in the axial direction of the anvil roll 51 (corresponding to the foregoing intersecting direction). A substrate can be welded by being sandwiched and heated between the anvil brock 511 and the following heating block 521 in the direction of the normal of the anvil roll 51 (corresponding to the foregoing thickness direction). In addition, the substrate can be cut by being sandwiched and pressed between the anvil brock 511 and the following cutter block 531 in the direction of the normal of the anvil roll 51. In the figure, the anvil brocks 511 are provided in the positions which divide along the circumferential direction the circumference of the anvil roll 51 into six equal parts, but the number of the anvil brocks 511 included in a single anvil roll 51 is not limited to six.
The sealing roll 52 is a rotating body placed at a position facing the anvil roll 51 as shown in
In the foregoing example, heat-welding (heat-sealing) is described. Though the configuration of apparatuses for ultrasonic welding (sonic-sealing) is partly different therefrom (e.g., the heating block 521 is replaced with ultrasonic horn), the basic operations such as transportation operation of the welding-and-cutting apparatus 50 are the same.
The cutter roll 53 is used, in the next cutting process (S108), when cutting the lower bandlike member 15 and the upper bandlike member 17 on a part of the cutting position CL along the intersecting direction. The cutter roll 53 is a rotating body placed at a position facing the anvil roll 51 and downstream from the sealing roll 52 in the transport direction. On the circumferential surface of the cutter roll 53, the cutter block 531 is provided along the axial direction of the cutter roll 53 (corresponding to the intersecting direction). These components have a positional relationship in which the anvil brock 511 and the cutter block 531 faces periodically by rotation of the anvil roll 51 and simultaneous rotation of the cutter roll 53 in the opposite direction. The cutter block 531 includes a cutter (not shown) along the axial direction (the intersecting direction). When the cutter faces the anvil brock 511 of the anvil roll 51 and comes into contact with a substrate, the substrate can be cut in the intersecting direction.
The transportation-assisting rolls 54 are provided upstream and downstream from the anvil roll 51 in the transport direction. The transportation-assisting rolls 54 assist the transportations of the lower bandlike member 15 and the upper bandlike member 17 along the circumferential surface of the anvil roll 51, and adjusts the magnitude of tension which is exerted on the lower bandlike member 15 and the upper bandlike member 17 which are being transported. Uniform tension during transportation makes it possible to prevent the occurrence of faulty weld and/or displacement at the time of welding.
Here, the description return again to the welding process (S107).
The welded sections sl are formed within the second areas according to the shape of the protruding section 522 of the foregoing heating block 521. The second areas are areas located on both sides of the first area in the transport direction, and each has a predetermined width in the transport direction. In
Each of the second areas are defined so that a part thereof overlaps the first area in the transport direction. Specifically speaking, the second area is defined so that the distance xsl from the cutting position CL to an end section of the second area (the end section closer to the cutting position CL) in the transport direction is smaller than the distance x (see
The welded sections sl and the adhesion areas HMA are formed overlapping on partial areas, and this enables the elastic members 8L, 8B and 8F to be fixed more firmly, the elastic members 8L, 8B and 8F being stretched and adhering to the lower bandlike member 15 (the upper bandlike member 17) in the adhesion areas HMA. For example, when the fitting-gather elastic members 8F (hereinafter merely referred to as “elastic members 8F”) are cut at a cutting position CL in the following cutting process (S108), those elastic members 8F contract in the transport direction from a portion which has been cut. At this stage, if the elastic members 8F insufficiently adhere to the lower bandlike member 15 (the upper bandlike member 17), the elastic members 8F are removed (elastic drop-off) from the adhesion areas HMA; consequently, the elastic members 8F cannot provide stretchability to the lower bandlike member 15 (the upper bandlike member 17). This causes a problem such that fitting around the wearer's waist deteriorate when a diaper 1 is worn. As opposed thereto, the welded sections sl are formed overlapping some parts of the adhesion areas HMA as in the present embodiment. Thereby, the elastic members 8F adhere to the lower bandlike member 15 (the upper bandlike member 17) on the adhesion areas HMA. In addition thereto, the elastic members 8F become more likely to be held while being sandwiched between the lower bandlike member 15 and the upper bandlike member 17 which are pressurized by the welded sections sl in the thickness direction. This makes the elastic members 8F to be less likely to be removed.
It is desirable that an overlapping part of the welded sections sl and the adhesion areas HMA in the transport direction is as small as possible. The reason is that, if the welded sections sl are formed so as to overlap the entire areas of the adhesion areas HMA, welding strength of the welded sections sl may be insufficient due to the oil of hot-melt adhesive which forms the adhesion areas HMA. Putting of hot-melt adhesive onto the heating block 521 used in heat welding and/or the ultrasonic horn used in ultrasonic welding may cause problems such as increase of the number of maintenance operations of the welding-and-cutting apparatus 50, or may prevent continuous manufacturing of the diapers 1. Accordingly, in the present embodiment, the welded sections sl overlap only partial areas of some of the adhesion areas HMA, and this enables the welded sections sl to obtain sufficient welding strength. In the case shown in
In the present embodiment, there is a case in which adhesive is applied on an area other than the first area. That is, in some cases, adhesive is applied on the second areas. In this case, the amount per unit area (basis weight) of adhesive which is put on the second area is smaller than at least the amount per unit area (basis weight) of adhesive which is put on the first area. This allows the foregoing problems to become less likely to happen, and therefore the welding strength of the welded sections sl formed in the second areas becomes less likely to deteriorate. However, if the welding strength of the welded sections sl formed in the second areas is sufficient, the amount per unit area of adhesive which is put on the second areas may be larger than the amount per unit area of adhesive which is put on the first area. In other words, the amount per unit area of adhesive may be determined so that welding strength when welding is performed in the second areas is larger than welding strength when welding is performed in the first area.
It goes without saying that adhesive may be put on an area other than the first area and the second areas.
In the present embodiment, the welded sections sl are formed so that the distance (gsl) between two welded sections sl and sl adjacent in the intersecting direction is larger than the diameter (thickness) of each of the elastic members 8B, 8F and 8L.
In the present embodiment, in most area of the second area of the lower bandlike member 15 (the upper bandlike member 17) where the welded sections sl are formed, the surface of nonwoven fabric keeps in good condition. For example, if the adhesion areas HMA are formed within a wide range of the second area or if the surface of nonwoven fabric in the second area is damaged by other means such as a cutter, it is possible that welding is failed which results in insufficient strength of the welded sections sl. But, in the present embodiment, any treatment to damage the surface of nonwoven fabric is not made at least within the second area. Accordingly, sufficient welding strength can be ensured by normal welding.
The lower bandlike member 15 and the upper bandlike member 17 which have been welded are directly transported on the circumferential surface of the anvil roll 51 of the welding-and-cutting apparatus 50 (see
In the present embodiment, while the elastic members 8B, 8F and 8L being stretched in the transport direction and being sandwiched between the lower bandlike member 15 and the upper bandlike member 17, the elastic members are held by the adhesion area HMA formed in the first area. Accordingly, stretching-and-contraction force due to the elastic members 8B, 8F and 8L is exerted on the adhesion area HMA along the transport direction. In this case, if the elastic members 8B, 8F and 8L are cut at the cutting position CL, the adhesion area HMA is pulled by the elastic members which are contracting, and the adhesion area HMA deforms so that the adhesion area HMA itself contracts along the transport direction while moving along the transport direction towards a direction away from the cutting position CL. On the other hand, in the second areas placed on the sides of the first area in the transport direction, adhesive is not put or adhesive is put of a low basis weight with which stretching-and-contraction force is not exerted. And, in the second areas, stretching-and-contraction force is not exerted on the lower bandlike member 15 and the upper bandlike member 17. Accordingly, in the second areas, the elastic members are likely to contract along the transport direction (the transverse direction of a diaper 1), and the lower exterior member 5 and the upper exterior member 7 deform so as to shrink towards the transverse center, by an amount corresponding to the contraction of the elastic members.
This narrows the welded sections sl and the adhesion area HMA which extend beyond both transverse end sections of the exterior member 10 of a pants-shaped diaper 1. Consequently, the welded sections sl and the adhesion area HMA become less likely to looks protruding, and the appearance of the diaper 1 becomes good. For example, in
The lower exterior member 5 and the upper exterior member 7, which have been cut and separated from the lower bandlike member 15 and the upper bandlike member 17, are transported being absorbed on the anvil roll 51, and are ejected as a single piece of a diaper 1 to outside the welding-and-cutting apparatus 50. Through these processes, the diaper 1 is manufactured.
In the foregoing embodiment, the adhesion areas HMA are formed by applying adhesive such as hot-melt type adhesive onto the first area, the first area being defined on the bandlike member which are being transported (S103 in
Applying the adhesive to the elastic members increases adhesion of the elastic members on the adhesion areas HMA, and this makes it easier to prevent problems such as elastic drop-off. If the adhesion-area forming process and the elastic-member placing process are simultaneously performed, the diapers 1 can efficiently be manufactured. However, when applying adhesive only to the elastic members, it should be careful not to displace the positions of the adhesion areas HMA in the transport direction. That is, it is necessary to make adjustment so that the areas in which adhesive is applied to the elastic members and the positions where the elastic members are placed on the band-like substrate are not displaced.
When adhesive is applied onto an elastic member, an amount of adhesive applied is different between the following parts of the elastic member: the part which is placed within the first area; and the part which is placed within the second area. For example, adhesive is not applied onto the second areas. Or, the basis weight of adhesive applied to the part of the elastic member within the first area is larger at least than the basis weight of adhesive applied to the part of the elastic member within the second area. In other words, concerning adhesive which is applied in peripheral parts of the elastic member, the amount (weight) per unit area of the adhesive within the first area is larger than that of the adhesive within the second area. If adhesive is put in the foregoing manner, welding strength when welding is performed in the second areas may be larger than welding strength when welding is performed in the first area.
In the second embodiment, a method for manufacturing a disposable diaper consisting of three pieces (diaper 2) will be described.
<Basic Configuration of Diaper 2>
The diaper 2 which consists of three pieces and is manufactured in the second embodiment includes, as a first component, an absorbent main body 3 which is to be brought into contact with a wearer's crotch and to absorb excrement such as urine. The diaper 2 includes: a ventral band member 30a which covers a wearer's ventral part, as a second component; and a dorsal band member 30b which covers a wearer's dorsal part, as a third component. As for the diaper 2 in
Both of the ventral band member 30a and the dorsal band member 30b are made of flexible sheets such as nonwoven fabric, and are a sheet member having a substantially rectangular shape when viewed from above. In the second embodiment, the ventral band member 30a is formed by stacking and joining a piece of lower nonwoven fabric 31a and a piece of upper nonwoven fabric 32a. And also, the dorsal band member 30b is formed by stacking and joining a piece of lower nonwoven fabric 31b and a piece of upper nonwoven fabric 32b. While being stretched along the transverse direction, the waist elastic members 8B and the fitting-gather elastic members 8F are placed between the lower nonwoven fabric 31a and 31b and the upper nonwoven fabric 32a and 32b. Stretchability is thereby provided to the ventral band member 30a and the dorsal band member 30b of the diaper 2.
On the transverse end sections of the absorbent main body 3, the leg-gather elastic members 8L are placed while being stretched along the longitudinal direction. And, stretchability is thereby provided to the absorbent main body 3 (stretchability is provided around the wearer's legs).
The detailed description of components of the diaper 2 is omitted because a disposable diaper consisting of three pieces itself is publicly known.
<Method for Manufacturing Diaper 2>
A method for manufacturing diapers 2 of the second embodiment will be described.
First, the substrate of the diapers 2 is transported along a certain transport direction at a certain transport speed (S201). The “substrate of the diapers 2” is composed of a ventral bandlike member 31a1 (a ventral bandlike member 32a1) and a dorsal bandlike member 31b1 (a dorsal bandlike member 32b1). The ventral bandlike member 31a1 (the ventral bandlike member 32a1) is a member in which a plurality of pieces of the lower nonwoven fabric 31a (the upper nonwoven fabric 32a) are continuously linked in the transverse direction; the lower nonwoven fabric 31a (the upper nonwoven fabric 32a) constitutes the ventral band member 30a. Also, the dorsal bandlike member 31b1 (the dorsal bandlike member 32b1) is a member in which a plurality of pieces of the lower nonwoven fabric 31b (the upper nonwoven fabric 32b) are continuously linked in the transverse direction; the lower nonwoven fabric 31b (the upper nonwoven fabric 32b) constitutes the dorsal band member 30b. These members are transported in the transport direction while the members each keep their position in relation to each other at certain distances in the intersecting direction. The definitions of “the transport direction” and “intersecting direction” are the same as in the first embodiment.
Hot-melt type adhesive is put on the first areas of the substrate which is being transported, and the adhesion areas HMA are formed (S202). The first areas where the adhesion areas HMA are formed are substantially the same as in the first embodiment. Each first area includes a cutting position CL on the substrate, and has a certain width in the transport direction. Thereafter, the waist elastic members 8B and the fitting-gather elastic members 8F are placed while being stretched in the transport direction (S203). At this stage, the elastic members 8B and 8F are placed so that the partial areas of the elastic members 8B and 8F respectively overlap the adhesion areas HMA formed in the first area. And, the elastic members 8B and 8F adhere to the ventral bandlike member 31a1 and the dorsal bandlike member 31b1 on the overlapping area. After the elastic members are placed, the ventral bandlike member 32a1 is stacked on the ventral bandlike member 31a1 and the elastic members 8B and 8F (S204). Accordingly, the elastic members 8B and 8F are fixed to the substrates (the ventral bandlike member 31a1 and the ventral bandlike member 32a1) while being sandwiched in the thickness direction between the substrates. The elastic members 8B and 8F can exert stretching-and-contraction force in the transverse direction (transport direction) on the edge sections 30ae and 30be of the diaper 2. Similarly, the dorsal bandlike member 32b1 is stacked on the dorsal bandlike member 31b1 and the elastic members 8B and 8F. In the foregoing processes, the lower nonwoven fabric may be stacked on the upper nonwoven fabric which is being transported.
Subsequently, the absorbent main body 3 is placed and joined so as to bridge between the ventral band member 30a and the dorsal band member 30b (S205). With hot-melt adhesive, etc., the ventral band member 30a and the dorsal band member 30b is joined to the absorbent main body 3.
Thereafter, the ventral band member 30a and the dorsal band member 30b which are stacked are welded on the second areas (S207). The second areas are substantially the same as in the first embodiment. The second areas are respectively place on both sides of the first area in the transport direction, and each have a certain width in the transport direction. The operation of the welding process itself is substantially the same as in the first embodiment, and is performed using the welding-and-cutting apparatus 50. Thus, a plurality of the welded sections sl are formed at intervals along the intersecting direction so that some of the welded sections partially overlap the adhesion areas HMA. In the second embodiment, welded sections sl in which a small amount per unit area of adhesive is applied (or adhesive is not applied) within the second area are formed, and thereby, welding can be performed so that sufficient welding strength is ensured.
Finally, the ventral band member 30a, the dorsal band member 30b and the elastic members 8B and 8F are cut together at the cutting position CL (S208). The operation of cutting process is also substantially the same as in the first embodiment, and the elastic members 8B and 8F which are stretched in the transport direction contract along the transport direction towards a direction away from the cutting position CL. As the elastic members contract, the band member edge sections 30ae and 30be deform so as to shrink along the transport direction. Since the edge sections of the diaper 2 which extend protruding transversely outwardly shrink transversely inwardly, the edge sections become less likely to be noticeable. This makes the appearance of the diaper 2 good.
While the embodiments according to the invention are described above, the above-mentioned embodiments are provided for facilitating the understanding of the invention, and are not to be interpreted as limiting the invention. As a matter of course, the invention can be altered and improved without departing from the gist thereof and the invention includes equivalent thereof. For example, the invention can be altered as described below.
In the foregoing embodiment, after the elastic members are placed on the lower substrate (e.g., the lower bandlike member 15) which is being transported, the exterior member of an absorbent article is formed by stacking on and joining to the upper substrate (e.g., the upper bandlike member 17). However, a process for forming the exterior member is not limited thereto. For example, the elastic members may be placed between the lower substrate and the upper substrate which are being transported in parallel in a state in which these substrates faces each other. In any way, a method for manufacturing an absorbent article according to the present application can apply to any configuration for forming an exterior member in which the elastic members are placed, the elastic members being stretched and sandwiched between a first substrate and a second substrate.
In the foregoing embodiment, using the welding-and-cutting apparatus 50, the welding process (S106, for example) and the cutting process (S107) are performed as a series of operations. However, these processes may be performed individually. For example, the following configuration is acceptable. Using a first anvil roll and a second anvil roll instead of the anvil roll 51 of the welding-and-cutting apparatus 50, the welding process is performed while the band-like substrate is being transported by the first anvil roll. And then, the cutting process is performed while the band-like substrate is being transported by the second anvil roll. In addition, a configuration in which the welding process alone is performed with the anvil roll and the cutting process is individually performed with another cutting device may be employed. Further, any other configuration may be employed depending on the place or conditions of a manufacturing line.
In the foregoing embodiment, nonwoven fabric is provided as an example of the materials of the lower exterior member 5 and the upper exterior member 7. However, the materials are not limited to nonwoven fabric. For example, woven fabric or any other sheet member except for woven fabric may also be used.
In the foregoing embodiment, rubber thread is provided as an example of the elastic members 8. However, this invention is not limited thereto. For example, band-like rubber may be used as the elastic members 8, and band-like nonwoven fabric with stretchability or band-like resin film with stretchability may also be used.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-038859 | Feb 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/050337 | 1/8/2015 | WO | 00 |
