JP4749286B2 - Method for producing elastic sheet - Google Patents

Description

  The present invention relates to a method for producing an elastic sheet and a method for producing a pants-type wearing article.

  Conventionally, as a pants-type disposable diaper, an elastic stretch part is formed on the peripheral part of the waist opening (hereinafter also referred to as the waist part) or the waist part located below the waist part and above the leg opening part. Is known. As a method for forming the elastic stretchable portion, a method is generally used in which a thread-like or belt-like elastic member is fixed between two substantially inelastic sheets in a stretched state, and a gather is formed by contraction of the elastic member. .

Further, as another method of forming an elastic stretchable part on a pants-type disposable diaper or the like, a method using a stretchable sheet obtained by a method that does not form a gather is known. For example, Patent Document 1 describes that different stretch characteristics are imparted to the waist portion and other portions by using different stretch sheets.
Furthermore, Patent Document 2 discloses that a stretch-free laminated web having zero strain is supplied between pressurizing apparatuses having three-dimensional surfaces that mesh with each other, and a part of the web is stretched by pressurization using the apparatus. A method of elasticity is described.

JP-T-2005-517496 Japanese Patent No. 3516679

  In the above-described method of forming a gather by contraction of an elastic member, an inelastic sheet is gathered in a relaxed elastic stretchable part, and the appearance cannot be said to be good.

On the other hand, the method of forming the elastic stretchable part using the above-described stretchable sheet reduces the elastic member and the adhesive for bonding thereof compared to the method of forming a gather by fixing the thread-like or belt-like elastic member. It is possible to prevent the stretchable sheet and the diaper from becoming hard due to the adhesive, and it is possible to reduce the manufacturing cost.
However, in the conventional stretchable sheet, the stretchable sheet itself or a part of a pants-type disposable diaper using the stretchable sheet or the like is an area rich in stretchability, or on the contrary, only a part of the stretchable sheet is substantially non-stretchable. If you want to use one elastic sheet, it is necessary to combine one elastic sheet with another elastic sheet or other non-elastic sheet. There is an inconvenience that the manufacturing process becomes complicated, such as an increase in the number of materials and a position adjustment between a plurality of sheets.

  Furthermore, by using a belt-like sheet having stretchability in the longitudinal direction in the entire region in the width direction, a so-called transverse flow method (a method in which a diaper is manufactured through a diaper continuous body having a configuration continuous in the width direction of the diaper), When trying to manufacture a disposable diaper, the sheet stretches due to the tension applied to the sheet during conveyance, and the amount of elongation varies with the variation in tension. A pants-type disposable diaper with a high finishing accuracy, in which leg holes are formed on a sheet, a folding position when the sheet is folded in two, a seal position when a predetermined portion of the folded sheet is sealed, etc. It is difficult to produce stably. Although it is conceivable to convey the stretchable sheet without applying tension, the facilities are excessive, which is not realistic. Such a problem of the stretch amount of the stretchable sheet also exists when the stretchable sheet is used for other purposes.

Accordingly, an object of the present invention is to produce a stretchable sheet that has a stretchable region and a low or non-stretchable region that is less stretchable than that, has a good appearance, and can be conveyed while suppressing fluctuations in elongation. An object of the present invention is to provide a method for producing a stretchable sheet.
Another object of the present invention is to provide an outer packaging material having a stretchable region and a low or non-stretchable region that is less stretchable, has a good appearance, and has a high finish accuracy. It is in providing the manufacturing method of the underpants type wearing article which can be manufactured well.

  The present invention is a stretching step for improving the stretchability of the belt-like sheet by stretching the belt-like sheet whose stretchability is improved by stretching between a pair of tooth-gap rolls having tooth grooves engaged with each other and stretching in the longitudinal direction. And the manufacturing method of the elastic sheet which comprises the joining process which joins this belt-like sheet after extending with the 2nd belt-like sheet, and obtains the elastic sheet of the structure where the both belt-like sheets were laminated, In the process, as a pair of tooth gap rolls, an extension part that extends the belt-like sheet in the longitudinal direction thereof, or the belt-like sheet is extended in the longitudinal direction at a lower magnification than the extension part, or the belt-like sheet In the longitudinal direction of the belt-like sheet, each of the stretch region and the low or non-stretch region is intermittently formed in the joining step. , The belt-like sheet after stretching is obtained by achieving the above object by providing a method for producing a stretchable sheet bonded to the second strip-shaped sheet that is substantially elongated in the longitudinal direction.

  Further, the present invention is a method for manufacturing a pants-type wearing article comprising an outer packaging material, wherein a belt-like sheet whose stretchability is improved by stretching is bitten between a pair of tooth gap rolls having tooth grooves that engage with each other. Stretching in the longitudinal direction to improve the stretchability of the strip-like sheet, joining step for joining the strip-like sheet after stretching to the second strip-like sheet, and the outer packaging material continuum including both strip-like sheets in the width direction A folding process in which the outer packaging material is folded into two, a sealing process in which a side seal is formed by applying a sealing process to the folded outer packaging material continuum, and the folded outer packaging material continuum is cut into individual pants-type wearing articles. A step of separating, and in the stretching step, as a pair of tooth gap rolls, a stretching portion that stretches the strip-shaped sheet in the longitudinal direction thereof, and the longitudinal direction of the strip-shaped sheet as compared to the stretching portion In the longitudinal direction of the belt-like sheet, the stretchable region and the low- or non-stretchable region are intermittently stretched at a low magnification or with a low or non-stretched part that does not stretch the belt-like sheet in the longitudinal direction. In the joining step, the object is achieved by providing a method for manufacturing a pants-type wearing article in which the stretched strip-like sheet is joined with a second strip-like sheet that does not substantially extend in the longitudinal direction. Achieved.

According to the method for producing a stretchable sheet of the present invention, it has a stretchable region and a low stretchable region or a non-stretchable region that is less stretchable than the stretched region. Can be produced efficiently.
According to the method for producing a pant-type wearing article of the present invention, the pant has an outer packaging material having a stretchable region and a low-stretchable region or a non-stretchable region that is less stretchable, has a good appearance, and has high finishing accuracy. A mold wearing article can be manufactured stably and efficiently.

The present invention will be described below based on preferred embodiments with reference to the drawings.
As shown in FIG. 1, the elastic sheet manufacturing method of the present embodiment includes a pair of tooth groove rolls 31 having tooth grooves extending in the axial direction and meshing with each other, as shown in FIG. 32, the film is stretched by being sandwiched between the two, and a stretching process for improving the stretchability of at least a part of the belt-shaped sheet 120 ′ and a bonding process for bonding the stretched belt-shaped sheet 120 to the second belt-shaped sheet 130 are provided. Thus, the elastic sheet 110 having a structure in which the two belt-like sheets 120 and 130 are laminated is obtained.

The belt-like sheet whose stretchability is improved by stretching is not stretchable before stretching and expresses stretchability by stretching, and has some stretchability before stretching, and stretchability is improved by stretching. Both of them are included, but those which do not substantially have stretchability before stretching and exhibit stretchability by stretching are preferred.
Here, “stretchability is improved” means that it becomes easier to stretch with a small force, and specifically, the elongation increases when a load of 1.0 N / 25 mm is applied, or breakage occurs. It means that the elongation increases.
For example, the elongation when a 1.0 N / 25 mm load is applied can be measured as follows. A test piece having a width (length in the same direction as the width direction of the belt-like sheet) of 25 mm and a length (length in the same direction as the longitudinal direction of the belt-like sheet) of 75 to 100 mm is cut out, and the test piece is obtained by a tensile tester. Is measured for elongation in the length direction until the load becomes 1.0 N (initial length 50 mm). Similarly, the elongation at break is measured by pulling a test piece having a width of 25 mm with a tensile tester and breaking.

The belt-like sheet whose stretchability is improved by stretching is a type in which elastic fibers and inelastic fibers are mixed, or a type in which an elastic layer having elastic stretchability and a substantially inelastic nonelastic fiber layer are laminated. In addition, those in which the non-elastic fiber or the non-elastic fiber layer changes to a structure that hardly inhibits the expansion and contraction of the elastic fiber or the elastic layer by stretching can be preferably used.
Examples of the change to a structure that does not easily inhibit expansion / contraction include stretching and cutting of non-elastic fibers, splitting of non-elastic fiber layers, stretching and cutting of constituent fibers of non-elastic fiber layers, and destruction of joint points between constituent fibers. It is done.
In the case of the laminated type, the non-elastic fiber layer may be disposed on both sides of the elastic layer or may be disposed only on one side.

  The elastic layer has a property that it can be stretched in the plane direction in a single state or in a stretched stretched sheet state and contracts when released from the stretched force, and at least in one direction parallel to the surface , The residual strain when contracted after 100% elongation is preferably 20% or less, particularly preferably 10% or less. This value is preferably satisfied at least in the same direction as the direction of stretching of the belt-like sheet, and is preferably satisfied in the longitudinal direction and / or the width direction of the belt-like sheet.

The elastic layer is preferably an elastic fiber layer including elastic fibers containing an elastic material. Examples of the elastic material include thermoplastic elastomers, rubbers, ethylene / propylene copolymers, and among these, thermoplastic elastomers are preferable. Examples of the thermoplastic elastomer include polyurethane, styrene (SBS, SIS, SEBS, SEPS, etc.), olefin (copolymers such as ethylene, propylene, butene, etc.), vinyl chloride, and polyester. These can be used individually by 1 type or in combination of 2 or more types.
As an elastic layer, it can replace with what consists of a fiber layer, and a film-like thing, a net-like thing, etc. can also be used. As the film or net forming material, the above-mentioned various elastic materials can be used.
When the elastic layer is a fiber layer containing elastic fibers, the elastic fiber content in the elastic layer is preferably 50 to 100% by weight, particularly 75 to 100% by weight. Examples of the non-elastic fiber in the case where the elastic layer includes the non-elastic fiber together with the elastic fiber include fibers constituting the non-elastic fiber layer described later. The elastic fiber can be obtained by a melt blown method, a spun bond method, a spinning blow method in which the spun bond method is combined with the melt blown method, or the like. The elastic fiber layer can be, for example, a web or a nonwoven fabric formed by a spinning blow method, a spun bond method, a melt blow method, or the like.

  The inelastic fiber layer has extensibility but is substantially inelastic. Here, extensibility refers to the case where the constituent fibers themselves are stretched, and even if the constituent fibers themselves are not stretched, the two fibers that have been heat-sealed at the intersection of the constituent fibers are separated from each other, or the heat between the fibers is The three-dimensional structure formed by a plurality of fibers may be structurally changed due to fusion or the like, or the constituent fibers may be broken, and the fiber layer may be elongated.

  Examples of the fibers constituting the inelastic fiber layer include fibers made of polyethylene, polypropylene, polyester (PET or PBT), polyamide such as nylon, and fibers made of biodegradable resin such as polylactic acid. The fibers constituting the inelastic fiber layer may be short fibers or long fibers, and may be hydrophilic or water repellent. Moreover, a core-sheath type composite fiber, a split fiber, a modified cross-section fiber, a crimped fiber, a heat-shrinkable fiber, or the like can be used. These fibers can be used singly or in combination of two or more.

The elastic layer and the non-elastic fiber layer are entirely or partially joined. As a method of joining the fiber layer and the non-elastic fiber layer, these layers are laminated and the fibers of both layers are entangled by the spunlace method, the hot air treatment such as the air-through method is used to determine the intersection of the fibers of both layers. Examples include a method of heat-sealing, a method of joining both layers by heat embossing, an adhesive, ultrasonic embossing, and the like.
In the case where a non-elastic fiber layer is integrated on one or both sides of the elastic fiber layer, the elastic fiber layer and the non-elastic fiber layer are the constituent fibers of the elastic fiber layer at and near the interface between the two layers. It is preferable that the intersections with the constituent fibers of the inelastic fiber layer are heat-sealed and bonded substantially uniformly over the entire surface. Such joining can be achieved by an air-through method or the like. By being bonded over the entire surface, it is possible to prevent the floating between the elastic fiber layer and the non-elastic fiber layer, that is, the formation of a space by separating the two layers. Moreover, it is preferable that the elastic fiber layer is integrated with the non-elastic fiber layer in a state where the constituent fibers maintain the fiber form. Further, in addition to the entire bonding by the air-through method, partial bonding by hot embossing or the like may be performed. As an aspect of being partially joined, there may be mentioned those in which joined portions having an arbitrary shape such as a circle or a rectangle are distributed in a dotted pattern in the plane direction.

  As the belt-like sheet whose stretchability is improved by stretching, various known ones can be used, for example, those described in Patent Document 2, JP-A 2003-73967, JP-A 2001-18309 described above. Etc. can also be used.

  FIG. 1 is a view showing an embodiment of a method for producing a stretchable sheet and a pants-type wearing article according to the present invention. FIG. 1 shows a belt-like sheet 120 ′ that exhibits stretchability by stretching, and is substantially in the longitudinal direction. The state which manufactures the elastic sheet 110 using the 2nd strip | belt-shaped sheet | seat 130 which does not expand | extend to 2 and the state which manufactures the pants-type disposable diaper 1 further using the elastic sheet 110 is shown.

  In the present embodiment, as shown in FIG. 1, a belt-like sheet 120 ′ that does not have stretchability in practice before stretching but develops stretchability by stretching is used as a pair of tooth groove rolls 31 in the stretching device 30. 32, the stretchable belt-like sheet 120 in which the stretchable region 12H and the stretchable low or non-stretchable region 12L are intermittently formed in the longitudinal direction is obtained. ing. Further, as the belt-like sheet 120 ′ exhibiting stretchability by stretching, a sheet having a structure having substantially non-elastic non-elastic fiber layers on both sides of an elastic fiber layer made of elastic fibers is used.

The pair of tooth groove rolls 31 and 32 has tooth grooves extending in the axial direction and meshing with each other on their peripheral surface portions. Moreover, as shown in FIG.1 and FIG.2, as shown in FIG.1 and FIG.2, the high extending | stretching part 31H, 32H and the low or non-extending part 31L, 32L are alternately formed. The high extension part 31H of the tooth groove roll 31 and the high extension part 32H of the tooth groove roll 32, and the low or non-extension part 31L of the tooth groove roll 31 and the low or non-extension part 32L of the tooth groove roll 32 are mutually The tooth gap rolls 31 and 32 are arranged so as to correspond.
As shown in FIG. 3, teeth 31a and 31b having a relatively high height H are formed in the high extension portions 31H and 32H so that the depth D of engagement between the pair of tooth gap rolls 31 and 32 is increased. The portion of the belt-like sheet 120 ′ that is caught between the high-stretched portions 31H and 32H becomes a stretchable region 12H that is stretched greatly in the flow direction and exhibits excellent stretchability.
On the other hand, in the low or non-stretched portions 31L and 32L in the present embodiment, teeth are not formed as shown in FIG. 4, and a portion of the belt-like sheet 120 ′ that passes between the low or non-stretched portions 31L and 32L. Is a low or non-stretchable region 12L that is hardly stretched in the flow direction and substantially does not develop extensibility and stretchability.

  In addition, as shown in FIG. 2, the pair of tooth space rolls 31 and 32 in the present embodiment has a portion of more than 50% (preferably a portion of more than 70%) in each circumferential direction as the highly elongated portions 31H and 32H. Therefore, good stretchability can be imparted to a wide range in the width direction of the outer packaging material 1 of the diaper 1 described later. On the other hand, the low or non-stretched portions 31L and 32L are formed at two locations sandwiching the axial centers of the tooth gap rolls 31 and 32, respectively.

  The meshing depth D (see FIG. 3) in the high stretched portions 31H and 32H of the pair of tooth gap rolls is 1.0 mm or more in order to increase the stretch ratio of the belt-like sheet and give the stretchable sheet good stretchability. Preferably, it is 2.0 mm or more. The engagement depth D of the pair of tooth gap rolls 31 and 32 is a length in which adjacent teeth 31a and 32a overlap when the tooth groove rolls 31 and 32 are engaged with each other and rotated as shown in FIGS. It is. The stretch ratio in the portion where the highly stretched portions 31H and 32H mesh with each other is preferably 1.5 to 5.0 times. The ratio (H1 / H2) of the draw ratio H1 at the portion where the high stretch portions 31H and 32H mesh with each other and the stretch ratio H2 at the portion where the low stretch portions 31L and 32L mesh together is 1.1 to 5.0. It is preferable that it is 2.0-3.0. Here, the draw ratio is defined by (length when material is stretched by meshing of rolls having tooth gaps) / (material length before being stretched by meshing of rolls).

Further, in the high extension portions 31H and 32H of the tooth gap rolls 31 and 32, the pitch P between adjacent teeth is preferably 1.0 mm to 5.0 mm, and the width W of each tooth is preferably the pitch P. Is less than ½, and the tooth height H is preferably greater than or equal to the pitch P.
If the shape of the tooth gap in each tooth groove roll satisfies such a condition, the belt-like sheet 120 ′ supplied between the tooth groove rolls 31 and 32 can be provided with a high stretchability that has not been achieved conventionally. . The pitch between adjacent teeth in the tooth gap rolls 31 and 32 refers to the distance between the center line of one tooth and the center line of an adjacent tooth. The tooth width of the tooth gap roll refers to the width of one tooth. The width of the teeth is not uniform, and a trapezoidal tooth that narrows from the root of the tooth toward the tip of the tooth as shown in FIG. 3 is preferable. In addition, the teeth may be rectangular or triangular. In this case, the width W of each tooth indicates the width of the root of the tooth. The height of the teeth of the roll refers to the length from the root to the tip of the teeth.

  In each of the tooth gap rolls 31 and 32, the corners in the roll circumferential direction at the tips of the teeth 31a and 32a are chamfered so as not to damage the belt-like sheet 120 ′ by the corners of 31a and 32a. It is preferable to keep it. The radius of curvature of chamfering is preferably 0.1 to 0.3 mm. In addition, at the boundary between the high-stretched portions 31H and 32H and the low or non-stretched portions 31L and 32L, the tooth height gradually decreases from the high-stretched portions 31H and 32H toward the non-stretched portions 31L and 32L. From the viewpoint of preventing damage to the belt-shaped sheet 120 ′, it is preferable that the height of the teeth gradually increase from the portions 31L and 32L toward the highly elongated portions 31H and 32H.

The tooth gap rolls 31 and 32 are engaged with each other and rotated when a driving force from a driving means (not shown) is transmitted to one of the rotation shafts. Separately from the teeth 31a and 32a, gears defined in JIS B1701 are attached to the shafts of the tooth gap rolls 31 and 32 as driving gears. In this case, the teeth 31a and 32a of the tooth gap rolls 31 and 32 are not in contact with each other, and the tooth gap rolls 31 and 32 can be rotated by meshing the driving gears.
In the present invention, the engagement between the tooth gap rolls includes the case where the teeth of one roll do not contact the teeth of the other roll.

  In order to stretch the belt-like sheet 120 ′ with the pair of tooth gap rolls 31 and 32 described above, as shown in FIGS. 1 and 4, while rotating the pair of tooth groove rolls 31 and 32 in the stretching apparatus 30. The belt-like sheet 120 ′ is supplied to the meshing portion P (see FIG. 2) of both rolls.

  In the present embodiment, as shown in FIG. 1, tension applying means 34 and 35 for applying tension to the belt-like sheet 120 ′ before and after the drawing process by the tooth gap rolls 31 and 32 are arranged before and after the drawing device 30. . The tension applying means 34 includes a pair of tension rolls 34 a and 34 b arranged on the upstream side of the tooth gap rolls 31 and 32. The tension applying means 35 includes a pair of tension rolls 35 a and 35 b disposed on the downstream side of the tooth gap rolls 31 and 32.

  From the viewpoint of more effectively imparting stretchability to the belt-like sheet 120 ′, the belt-like sheet 120 ′ is interposed between the tooth gap rolls 31 and 32 in a state where tension is applied to the belt-like sheet 120 ′ before stretching by the tension rolls 34a and 34b. It is preferable to supply '. The tension applied to the supplied belt-like sheet 120 'is preferably 10% to 80%, more preferably 20% to 70% of the breaking stress of the belt-like sheet 120' before stretching.

  From the same point of view, it is preferable to draw tension between the tooth gap rolls 31 and 32 by applying tension to the stretched belt-like sheet 120 with tension rolls 35a and 35b. The tension applied to the supplied belt-like sheet 120 'is preferably 5% to 80% of the breaking stress of the belt-like sheet 120 after the stretching process, and more preferably 10% to 70%. The breaking stress of the sheet is smaller after the processing than before the tooth gap extension processing. Further, the stretched belt-like sheet 120 provided with stretchability by the tooth gap stretching process is easily stretched even with a slight tension. From such a viewpoint, it is preferable that the tension applied to the strip-shaped sheet 120 that has been subjected to stretching processing is made weaker than the tension applied to the strip-shaped sheet 120 ′ before stretching.

In the present embodiment, the stretch-like region 12H having excellent stretchability and the non-stretchable region 12L having substantially no stretchability and stretchability are obtained by subjecting the belt-like sheet 120 ′ to stretching in this manner. A stretchable belt-like sheet 120 formed alternately in the longitudinal direction is obtained.
The stretchable region 12H and the low or non-stretchable region 12L are different in the degree of stretching, so that each region is easily stretched when pulled in the same direction as the longitudinal direction of the belt-like sheet (in particular, a load of 1.0 N / 25 mm). (Elongation when stretched until) is different.

Further, the stretchable region 12H and the low or non-stretchable region 12L are different in the degree of stretching, so that the maximum breaking strength or punch-through strength in those regions is different. That is, the maximum breaking strength or punch-through strength of the stretchable region 12H is smaller than the maximum breaking strength or punch-out strength of the low or non-stretchable region 12L.
The maximum breaking strength is, for example, a width (length in the same direction as the width direction of the belt-like sheet) of 25 mm and a length (longitudinal direction of the belt-like sheet) from each of the regions 12H and 12L in the stretched belt-like sheet. A test piece having a length of 75 to 100 mm is cut out, and the test piece is subjected to a tensile test so that the longitudinal direction of the belt-like sheet (the machine flow direction is the same as the longitudinal direction of the test piece) is the tensile direction. It can be judged by measuring the load when it is pulled and broken by a machine.
The penetration strength can be determined by, for example, preparing a test piece from each region and measuring the force required to penetrate the test piece with a push-pull gauge.

In the present embodiment, the belt-like sheet 120 (hereinafter also referred to as the first belt-like sheet 120) obtained as described above is stretched between the tension applying means 35 and the nip roll 36 while being continuously conveyed. The first belt-like sheet 120 in a state is bonded to the second belt-like sheet 130 that has been continuously conveyed.
The nip roll 36 includes a pair of rolls. The pair of rolls constituting the nip roll 36 is driven such that the rotational speed (peripheral speed, sheet feeding speed) is higher than that of the pair of rolls 35 a and 35 b constituting the tension applying means 35.

In the first belt-like sheet 120, the above-mentioned stretchable region 12H extends in the longitudinal direction of the sheet 120 between the tension applying means 35 and the nip roll 36, while the low or non-stretchable region 12L described above is the longitudinal length of the sheet 120. Little stretch in the direction. Moreover, the 2nd strip | belt-shaped sheet | seat 130 is a sheet | seat which does not expand | extend substantially.
Therefore, the first belt-like sheet 120 and the second belt-like sheet 130 are such that the stretchable region 12H of the first belt-like sheet 120 extends, while the low or non-stretchable region 12L of the first belt-like sheet 120 and the second belt-like sheet 130 are They will be joined together in a substantially unstretched state.

  In the present embodiment, the first belt-like sheet 120 and the second belt-like sheet 130 are bonded with the leg elastic members 61a and 61b and the waist elastic member 51 sandwiched between the two sheets as shown in FIG. Going in state. Specifically, an adhesive for fixing an elastic member is applied to a predetermined part of one or both of the two belt-like sheets 120 and 130 before the two belt-like sheets 120 and 130 are overlapped. In addition, in a state where the elastic members 61a, 61b, 51 are sandwiched in an extended state, the two belt-like sheets 120, 130 are narrowed by the nip roll 37 to fix the elastic members 61a, 61b, 51 and to fix the two belt-like sheets 120. , 130 are joined. The leg elastic members 61a and 61b are introduced between the belt-like sheets while being swung by a known swing guide in a direction perpendicular to the flow direction of the belt-like sheets 120 and 130.

In the present embodiment, the first belt-like sheet 120 imparted with stretchability by the stretching process in this way is stretched between the tension applying means 35 and the nip roll 36 provided on the downstream side thereof while being continuously conveyed. The stretchable sheet 110 having a structure in which the two belt-like sheets 120 and 130 are laminated is obtained by bonding the second belt-like sheet 130 that is stretched at a rate of 50 to 150% and that does not substantially stretch.
Even if the obtained elastic sheet 110 is in a relaxed state, no pleats due to the first belt-like sheet 120 are formed on the surface of the first belt-like sheet 120. Therefore, the appearance of the surface on the first belt-like sheet 120 side is good. In addition, since the stretchable region 12H and the low or non-stretchable region 12L of the belt-like sheet 120 exist and are continuous in one sheet, the external feeling on the surface on the first belt-like sheet 120 side is even better.
The obtained stretchable sheet 110 includes a stretchable region 110H including the stretchable region 12H of the belt-like sheet 120 and rich in stretchability, and a stretchable region 110L including the low or non-stretchable region 12L of the beltlike sheet 120 and inferior in stretchability. Are alternately formed in the longitudinal direction of the sheet 110. Therefore, the stretchable sheet 110 is suitable for manufacturing a large number of articles such as a pants-type wearing article having a portion rich in stretchability and a portion poor in stretchability.

In the manufacturing method of the underpants type wearing article of this embodiment, the elastic sheet 110 obtained as described above is used for manufacturing the underpants type disposable diaper 1.
In the present embodiment, as shown in FIG. 1, the stretchable sheet 110 is used as an outer packaging material continuous body (an original fabric of the outer packaging material 11). The stretchable sheet 110 is such that the belt-like sheet 120 becomes the outer layer sheet 12 constituting the outer surface side of the diaper of the outer packaging material 11 and the second belt-like sheet 130 becomes the inner layer sheet 13 constituting the inner surface side of the outer packaging material 11. use.

The pants-type disposable diaper 1 is manufactured in the same manner as a conventional so-called cross-flow type pants-type disposable diaper, except that the stretchable sheet 110 obtained as described above is used as a continuous outer packaging material. Can do.
For example, as shown in FIG. 1, the absorbent body 10 obtained by cutting the absorbent body continuum on the outer packaging material continuum 110 is rotated 90 degrees, and is bonded and fixed intermittently. The diaper continuous body 100 is obtained by removing the trim 111 for forming the leg opening by a rotary cutter, a laser cutter, or the like. Next, after folding both side portions 12a and 12b of the outer packaging material continuous body 110 in the diaper continuous body 100 so as to cover both end portions of the absorbent main body 10, the diaper continuous body 100 is folded in two. Next, after forming the side seal portions S, S by heat sealing, ultrasonic sealing, high frequency sealing or the like, or simultaneously with forming the side seal portions S, S, the pants type disposable diapers are cut into individual diapers. Get one.
The adhesive 15 that fixes the absorbent main body 10 to the outer packaging material continuous body 110 can be applied to either or both of the absorbent main body 10 and the outer packaging material continuous body 110. The trim 111 for forming the leg opening can be removed before the absorbent main body 10 is fixed.

According to the manufacturing method of the present embodiment, by using the stretchable sheet 110 obtained as described above as the outer packaging material continuous body, good stretchability is achieved in the absorbent article width direction (left-right direction in FIG. 6). A pants-type absorbent article having high finishing accuracy can be stably and continuously produced.
That is, even if the first belt-like sheet 120 is a sheet having excellent stretchability in the longitudinal direction, the outer packaging material continuous obtained by pasting it with the second belt-like sheet 130 that does not substantially stretch in the stretched state. The body 110 is hardly stretched any more, or when it is slightly stretched, the further stretch is abruptly suppressed (so-called stretching). Therefore, if the outer packaging material continuum 110 is transported with a certain level of tension, even if the tension applied to the outer wrapping material continuum 110 fluctuates during transportation, the elongation amount (elongation rate) of the outer packaging material continuum 110 is Fluctuation hardly occurs. Therefore, for example, a bonding position when the absorbent main body 10 is bonded to the outer packaging material continuous body 110, or a formation position when the leg hole 112 is formed in the outer packaging material continuous body 110 before and after fixing the absorbent main body 10 The folding position when the outer packaging material continuous body 110 (diaper continuous body 100) to which the absorbent main body 10 is fixed is folded in two, and the predetermined location of the outer packaging material continuous body 110 (diaper continuous body 100) to which the absorbent main body 10 is fixed. A pant-type disposable diaper with high finishing accuracy is prevented by preventing a shift in the sealing position when sealing and forming the side seal S, the cutting position when cutting and dividing the diaper continuous body 100 into individual diapers, and the like. It can be manufactured stably.

  Moreover, since the 1st strip | belt-shaped sheet | seat 120 and the 2nd strip | belt-shaped sheet | seat 130 are partially joined so that it may mention later, the stretchability of the continuous packaging material 110 derived from the stretchability of the 1st strip | belt-shaped sheet 120 is an adhesive agent. Since the degree is small even if it is not damaged or damaged, the resulting disposable diaper 1 is derived from the stretchability of the first belt-like sheet 120 so that the outer packaging material 11 has a diaper width direction (left and right in FIG. 5). Direction), exhibit good fit to the wearer's girth, and have excellent wearing feeling and leakage prevention.

  The perspective view of the underpants type disposable diaper 1 manufactured by the manufacturing method of this embodiment is shown by FIG. FIG. 6 shows a plan view of the developed state of the diaper shown in FIG. FIG. 7 shows a cross-sectional view taken along line II-II in FIG.

  The pants-type disposable diaper 1 (hereinafter also referred to as diaper 1) is a liquid-retaining top sheet 2, a liquid-impermeable or water-repellent back sheet 3, and a liquid-retaining property disposed between both sheets 2 and 3. A substantially vertically long absorbent body 10 having an absorbent core 4 and an outer packaging material 11 arranged on the back sheet 3 side of the absorbent body 10 and fixing the absorbent body 10 are provided.

  The outer packaging material 11 has an hourglass shape in which both side edges are bound inward in the central portion in the longitudinal direction, and defines the outline of the diaper. The diaper 1 is divided in the longitudinal direction in the unfolded state into an abdominal side A disposed on the wearer's abdomen, a back side B disposed on the dorsal side, and a crotch C positioned therebetween. In the outer packaging material 11, both side edges A 1 and A 2 on the ventral side A and both side edges B 1 and B 2 on the back side B are joined to each other, and the pair of side seal parts S is attached to the diaper 1 by the joining. , S, a waist opening 5 and a pair of leg openings 6 are formed.

  In the manufacturing method of the present embodiment described above, as shown in FIG. 1, in the stretchable sheet 110 used as the outer packaging material continuum, the side 110 </ b> L is located on the portion 110 </ b> L where the low or non-stretchable region 12 </ b> L is disposed The seal processing for seal part formation is given. Since the belt-like sheet 120 in the portion 110L is not stretched or stretched at a relatively low magnification even when the stretchable sheet 110 is in the stretched state, the portion 110L is sealed. The belt-like sheet 120 is prevented from being cut or damaged by the pressure or heat generated by the sealing process. The cutting and damage mentioned here may occur not only when the diaper is being manufactured, but also when the waist opening of the completed diaper is expanded for the consumer to wear, but the non-stretchable region 12L is disposed. Applying a sealing process to the formed portion 110L means applying a sealing process to a portion having a high material strength in a state of being hardly stretched, and a higher sealing strength can be expected. Therefore, damage or the like during wearing or wearing can be prevented. For the sealing process, various methods conventionally used for forming a side seal part such as a pants-type disposable diaper can be used. For example, one or both of them are folded between two heated sealing members. It is formed by sandwiching a continuous outer packaging material and heating and pressing from both sides.

  The top sheet 2, the back sheet 3 and the absorbent core 4 are integrated to form a vertically long absorbent body 10. As the surface sheet 2, the back surface sheet 3, and the absorptive core 4, the thing similar to what was conventionally used for this kind of diaper can be used, respectively. For example, as the absorptive core 4, what is comprised from the particle | grains and fiber material of a superabsorbent polymer, and is coat | covered with the tissue paper (not shown) etc. can be used. As shown in FIGS. 6 and 7, lateral cuffs 8, 8 made of a liquid-resistant or water-repellent and breathable material are formed on the left and right sides of the absorbent body 10 in the longitudinal direction. . In the vicinity of the free end of each side cuff 8, a side cuff elastic member 81 is disposed in an extended state. When the diaper is worn, the elastic member 81 is contracted, so that the side cuff 8 is erected and the liquid is prevented from flowing out in the width direction of the absorbent body 10.

  As shown in FIG. 7, the outer packaging material 11 has a structure in which an outer layer sheet 12 made of the belt-like sheet 120 that has developed elasticity by stretching and an inner layer sheet 13 made of the second belt-like sheet 130 are laminated. is doing. The outer layer sheet 12 forms the outer surface of the diaper 1, and the inner layer sheet 13 is disposed on the inner surface side of the outer layer sheet 12 and is partially joined.

  In the diaper 1, the outer layer sheet 12 and the inner layer sheet 13 are not joined to most of the abdominal part A, the back part B, and the crotch part C. Specifically, the outer layer sheet 12 and the inner layer sheet 13 are joined to each other at the side edge portions A1, A2, B1, and B2 of the ventral portion A and the back portion B by heat sealing, high frequency sealing, or ultrasonic sealing. Further, the peripheral edge 50 of the waist opening 5 and the peripheral edge 60 of each of the pair of leg openings 6 are joined to each other by an adhesive such as a hot-melt adhesive, and further, the ventral side A The back side part B and the crotch part C are joined at the center part in the diaper width direction. And it is not joined in parts other than those.

  Thus, in most of the abdominal part A and the back part B, the part where the outer packaging material 11 is hardened by the adhesive is minimized by adopting a configuration in which the outer layer sheet 12 and the inner layer sheet 13 are not joined. The portion of the outer surface of the diaper or the inner surface of the outer packaging material 11 that is not covered with the absorbent main body 10 can be made soft and soft to the touch. Moreover, since the air permeability of the outer packaging material 11 is maintained well, it is possible to provide a diaper that is not stuffy.

  Between the outer layer sheet 12 and the inner layer sheet 13 in each of the ventral side A, the back side B, and the crotch part C, the area of the non-joined portion other than the waist, side seals, and leg elastic members is the ventral side. It is preferable that it is 60 to 100% with respect to each area of A, the back part B, and the crotch part C, and it is more preferable that it is 70 to 100%. Those satisfying this condition are called "most".

  A plurality of waist elastic members 51, 51 are disposed along the peripheral edge of the waist opening 5 at the peripheral edge 50 of the waist opening 5 in each of the ventral side A and the back side B. These waist elastic members 51 and 51 are fixed in an extended state between the outer layer sheet 12 and the inner layer sheet 13 via an adhesive. In addition, leg elastic members 61a and 61b are also provided along the peripheral edge of each opening on the peripheral edge 60 and 60 of the leg opening that exists over the ventral side A, the crotch C and the back side B. It is arranged. These leg elastic members 61 a and 61 b are fixed in an extended state between the outer layer sheet 12 and the inner layer sheet 13 via an adhesive 62. As the waist elastic member 51 and the leg elastic members 61a and 61b, elastic materials such as natural rubber, polyurethane resin, foamed urethane resin, and hot melt elastic member are made into a thread (thread rubber) or a belt (flat), respectively. Those formed into (rubber) are preferably used.

  As shown in FIG. 6, the dimensions and ratios of the respective parts described in the present specification are in a natural state (external force such as tension is applied) when the diaper is in an unfolded state and the contraction force by the elastic members of the waist opening and the leg opening is released. The value measured in the state of not acting) or based on it.

  As shown in FIG. 7, the absorbent main body 10 is bonded to the inner layer sheet 13 of the outer packaging material 11 by the main body bonding portion 15 only in the central portion in the width direction, as shown in FIG. Since the expansion and contraction of the outer packaging material 11 is less likely to be hindered by the joining of the absorbent main body 10, a good fit can be obtained at the waistline portion. The width W1 of the joint portion 14 between the outer layer sheet 12 and the inner layer sheet 13 in the central portion of the outer packaging material 11 in the diaper width direction is the width W2 of the absorbent main body 10 in each of the ventral side portion A and the back side portion B. It is preferably 0 to 40%, and more preferably 0 to 30%.

Moreover, it is preferable that the width | variety of the main body junction part 15 is 10 to 90% of the width W2 of the absorptive main body 10 in each of the abdominal side part A and the back side part B, More preferably, it is 20 to 80%. .
Both ends in the longitudinal direction of the absorbent main body 10 are sandwiched and fixed between the folded portions 12a and 12b of the outer layer sheet folded back to the inner surface side of the diaper and the inner sheet 13 at the opening peripheral edges 5a and 5b of the waist opening. ing.

  In the wrapping material 11 in the diaper 1, the stretchable region 12 </ b> H of the belt-shaped sheet 120 is located in substantially the entire width direction of the abdomen A and the back B and in the entire region of the wrapping material 11 in the crotch C. Therefore, favorable stretchability in the diaper width direction can be obtained as well as the ventral side A and the back side B.

The second belt-like sheet 130 that does not substantially extend is a sheet that hardly expands or only slightly expands when it is pulled by hand.
The second belt-like sheet 130 has an elongation rate (elongation rate at 1.0 N / 25 mm) of 120% or less when stretched in the longitudinal direction until the tensile load per 25 mm width of the sheet becomes 1.0 N. It is preferable that there is an elongation rate, more preferably 100 to 110%.

The elongation percentage is measured as follows.
For example, a sample having a width of 25 mm and a length of 50 mm is prepared using a tensile tester such as Tensilon. The sample is pulled between 50 mm with a load of 1.0 N / 25 mm width, and the sample length after extension is measured as A. The elongation rate at that time is defined as follows in the case of the sample of 50 mm. (A-50) / 50 × 100. That is, (sample length after extension at 1.0 N−sample length before extension) / (sample length before extension) × 100. When the sample length after stretching is 100 mm, the stretching rate is 100%, and when the sample length after stretching is 150 mm, the stretching rate is 200%.

  As the sheet that does not substantially extend, a nonwoven fabric, a laminate of a nonwoven fabric and a resin film, a porous film, and the like are preferable. In the present embodiment, the sheet that does not substantially extend is the side that directly contacts the skin of the wearer of the outer envelope continuum 110, and more preferably a water-repellent nonwoven fabric from the viewpoint of preventing leakage of excrement.

As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment.
For example, in the manufacturing method of the elastic sheet 110 and the diaper 1 described above, a pair of tooth gap rolls provided with high stretched portions 31H and 32H and low or non-stretched portions 31L and 32L where no teeth are formed are used. The stretchable region 12H and the low or non-stretchable region 12L are intermittently formed in the longitudinal direction of the belt-like sheet. Instead, as shown in FIG. 8, the high stretched portions 31H and 32H and the high stretched region are formed. Using a pair of tooth gap rolls provided with a low or non-stretched portion 31L, L32 having a height lower than that of the teeth in the portion, the stretchable region 12H and the stretchable region 12 are less stretchable than the stretchable region 12H in the longitudinal direction. It is also possible to manufacture a stretchable sheet in which the non-stretchable region 12L is formed intermittently.

  Although the low or non-stretched portions 31L and L32 shown in FIG. 8 stretch the belt-like sheet 120 ', the expansion ratio is lower than that of the high stretched portions 31H and 31L. More specifically, the high stretched portions 31H and 32H have an axial centerline of each roll at a low or non-stretched portion 31L or 32L with a distance from the axial centerline (not shown) of each roll to the tooth tip. It is longer than the distance from the tooth tip (not shown). Thereby, the meshing depth of the pair of tooth gap rolls 31 and 32 is larger in the meshing in the high stretching portions 31H and 32H than in the meshing in the low stretching portions 31L and 32L. In this case, the portion including the stretchable region 12H is sealed by applying a sealing process for the side seal portion to the portion including the low or non-stretchable region 12L generated by being bitten by the low or non-stretched portions 31L and 32L. Damage prevention of the belt-like sheet 12 can be obtained as compared with the case of processing.

Moreover, in the manufacturing method of the diaper mentioned above, although the expansion-contraction area | region 12H of the strip | belt-shaped sheet | seat 120 was made to exist over the substantially full width of the stomach side part A and the back side part B of the diaper 1, instead of this, The low or non-extension area | region 12L may be arrange | positioned in the center part in the width direction of the diaper 1, and the expansion-contraction area | region 12H of the strip | belt-shaped sheet | seat 120 may be arrange | positioned at the both sides. By having a low or non-extension area at the center in the width direction, it is possible to prevent the crotch from becoming narrow due to contraction, while the abdominal side A and the back side B can have the necessary contractibility.
Thus, according to the manufacturing method of the pants-type wearing article of the present invention, using a single sheet having a plurality of regions having different stretch characteristics, a plurality of portions having different stretch characteristics in various patterns on the outer packaging material A pants-type wearing article formed with can be manufactured.

  In addition, instead of partially changing the depth of engagement of the tooth groove roll, by forming a portion where the tooth pitch is different from the other parts of each roll in each of the pair of tooth groove rolls, A part of the belt-like sheet can be stretched greatly, and the other part can be stretched to a lower magnification. Furthermore, it is also possible to form stretch regions having different stretch properties by partially varying both the meshing depth and the tooth pitch.

  Moreover, in the manufacturing method of the diaper 1 mentioned above, when joining the elastic strip | belt-shaped sheet | seat 120 and the 2nd strip | belt-shaped sheet | seat 130 which does not expand | extend substantially, an elastic member was fixed between both, but such A stretchable sheet or a pants-type wearing article may be manufactured without introducing an elastic member. Further, the sealing step and the step of cutting the outer packaging material continuous body may be performed in this order or simultaneously.

The method for producing a pant-type wearing article of the present invention is particularly suitable for the production of pant-type absorbent articles such as a pant-type disposable diaper, a pant-type sanitary napkin, and a pant-type incontinence pad. It can also be preferably used in the manufacture of sanitary shorts and other pants-type wearing articles that do not have an absorbent core.
Moreover, the manufacturing method of the elastic sheet of this invention is not restricted to what manufactures the elastic sheet which comprises all or one part of the outer packaging material of an underpants type wearing article, The other part in an underpants type wearing article is comprised. Sheets, and furthermore, tape-type diapers, sanitary napkins, poultices, supporters, masks and the like may be manufactured.

Drawing 1 is a figure showing one embodiment of the manufacturing method of the elastic sheet of the present invention, and a pants type wearing article. FIG. 2 is a view of the surface shape of the tooth gap roll in the stretching apparatus as seen from the roll axis direction. FIG. 3 is an explanatory view of the tooth gap of the tooth gap roll in the stretching device. Drawing 4 is a mimetic diagram showing signs that a belt-like sheet is drawn by a tooth gap roll in a drawing device. It is a perspective view which shows an example of the underpants type disposable diaper manufactured by the manufacturing method of this invention. It is a top view which shows the unfolded state of the diaper shown in FIG. It is the II-II sectional view taken on the line of FIG. It is a figure which shows a pair of tooth space roll used for other embodiment of this invention.

Explanation of symbols

1 Pants-type disposable diaper (pants-type wearing article)
2 Top sheet 3 Back sheet 4 Absorbent core 5 Waist opening 50 Waist opening peripheral edge 6 Leg opening 60 Leg opening peripheral edge 7 Girth part 10 Absorbent body 11 Outer packaging material 12 Outer sheet 13 Inner layer sheet 30 Stretched Device 31, 32 Gloss groove roll 31a, 32a Teeth 110 Outer packaging material continuum (elastic sheet)
120 'Strip-like sheet whose stretchability is improved by stretching processing 12H Stretch region 12L Low or non-stretchable region 120 Stretch-like sheet is enhanced by stretch processing and strip-shaped sheet 130 Second strip-shaped sheet

Claims (4)

Stretching process for improving the stretchability of the strip-shaped sheet by stretching the strip-shaped sheet whose stretchability is improved by stretching between a pair of tooth-gap rolls having meshing teeth and stretching in the longitudinal direction, and after stretching A method for producing a stretchable sheet comprising a joining step of joining the beltlike sheet to a second beltlike sheet, and obtaining a stretchable sheet having a structure in which the two beltlike sheets are laminated,
In the stretching step, as a pair of tooth gap rolls, a stretching section that stretches the strip sheet in the longitudinal direction thereof, or the strip sheet is stretched in the longitudinal direction at a low magnification as compared with the stretching section, or Using the one having a low or non-stretched part that does not stretch the belt-like sheet in its longitudinal direction, the stretchable region and the low or non-stretchable region are intermittently formed in the longitudinal direction of the belt-like sheet,
In the joining step, a method for producing a stretchable sheet, wherein the stretched belt-like sheet is joined with a second belt-like sheet that does not substantially stretch in the longitudinal direction in a state where at least the stretchable region is stretched . Method for producing a stretchable sheet according to claim 1, wherein the high draw unit satisfying the following conditions (1) to a part of the pair of the tooth roll each circumferential direction is formed.
(1) The pitch of adjacent teeth is 1.0 mm to 5.0 mm, the width of each tooth is less than ½ of the pitch, and the height H of each tooth is equal to or greater than the pitch. . A method for producing a pants-type wearing article comprising an outer packaging material,
A belt-like sheet whose stretchability is improved by stretching is stretched in the longitudinal direction by being bitten between a pair of tooth-gap rolls having mutually meshing tooth spaces, and a stretching step for improving the stretchability of the belt-shaped sheet, the stretched sheet A joining step for joining the belt-like sheet to the second belt-like sheet, a two-folding step for folding the outer packaging material continuum including the two belt-like sheets in the width direction, and a sealing process for the folded outer packaging material continuum. Comprising a sealing step of forming a seal portion, and a step of cutting the folded outer packaging material continuous body into individual pants-type wearing articles,
In the stretching step, as a pair of tooth gap rolls, a stretching portion that stretches the belt-like sheet in the longitudinal direction thereof, or the belt-like sheet is stretched in the longitudinal direction at a low magnification as compared with the stretching portion, or Using the one having a low or non-stretched part that does not stretch the belt-like sheet in its longitudinal direction, the stretchable region and the low or non-stretchable region are intermittently formed in the longitudinal direction of the belt-like sheet,
In the joining step, a method for producing a pants-type wearing article in which the stretched belt-like sheet is joined to a second belt-like sheet that does not substantially stretch in the longitudinal direction with at least the stretchable region stretched . The manufacturing method of the underpants type wearing article of Claim 3 which performs a sealing process in the said sealing process in the site | part by which the said low or non-stretching area | region is distribute | arranged in the said outer packaging material continuous body.

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