JP4633020B2 - Manufacturing method of pants-type disposable absorbent article - Google Patents

Description

  The present invention relates to a method for producing a pants-type disposable absorbent article.

Conventionally, as a pants-type disposable diaper, in addition to the peripheral edge of the waist opening and the peripheral edge of the leg opening, an elastic member is also provided on the waistline located below the peripheral edge of the waist opening to provide elastic elasticity The thing which gave is known.
Generally, when elastic stretchability is imparted to a disposable diaper, a stretched thread-like or belt-like elastic member is fixed between two substantially non-stretchable sheets via an adhesive, and the elastic member is attached to the disposable diaper. A method of forming a gather by shrinking is common.
For example, Patent Document 1 discloses a continuous outer packaging material in which the elastic direction member for forming a waistline gather is fixed between two sheets in a stretched state, and the width direction of the pants-type disposable diaper is the machine direction. In the outer packaging material continuum, the absorbent main body is intermittently fixed in the direction orthogonal to the machine direction, and then cut to produce a pant-type diaper. . However, depending on the method of forming the waist gathers by fixing the elastic member between the two sheets, it is necessary to apply an adhesive to fix the elastic member between the two sheets. It is difficult to further improve the softness and breathability of diapers. On the other hand, if the coating amount of the adhesive is reduced in order to improve the softness and the air permeability, the elastic member is not sufficiently fixed, and the fitting property and the leakage preventing property are lowered.

  In addition, as another manufacturing method of a pants-type disposable diaper, a method of manufacturing a pants-type diaper using a machine direction as a vertical direction when the pants-type disposable diaper is used is also known (see Patent Document 2). In this manufacturing method, by arranging an elastic member along the flow direction, stretchability can be imparted in the longitudinal direction when it is made a diaper, but stretchability in the width direction when it is made a diaper. In order to impart, the elastic members are sequentially introduced in a direction orthogonal to the flow direction. Introducing an elastic member that stretches in the direction (width direction) perpendicular to the flow direction of the strip material that is continuously conveyed toward the machine direction causes shrinkage in the width direction of the diaper and suppresses shrinkage in the width direction This would place restrictions on the stress design. Moreover, a complicated apparatus is required for introducing the elongated elastic member, and high-speed productivity is hindered.

JP-A-6-296638 JP-A-2-140163

  By the way, the elastic sheet obtained by the method which does not form a gather is known as a material used for clothes. However, it has been difficult to impart desired stretch performance in the width direction of the disposable diaper using such a sheet, particularly a sheet exhibiting superior stretchability in the width direction than the longitudinal direction.

  Accordingly, an object of the present invention is to enable efficient and continuous production of a pants-type disposable absorbent article in which the waistline portion is well stretched in the absorbent article width direction by using a belt-like sheet having elasticity in the width direction. It is providing the manufacturing method of a pants-type disposable absorbent article.

  The present invention is a method for producing a pants-type disposable absorbent article comprising an absorbent body including an absorbent core and an outer packaging material, and intermittently conveys a belt-like sheet having stretchability in the width direction. After cutting and rotating the short object generated by cutting 90 degrees, and connecting to obtain a belt-like sheet having machine direction stretchability, the belt-like sheet having machine direction stretchability and machine direction stretchability A separate belt-like sheet having the elastic member sandwiched between the two to obtain an outer packaging material continuous body, the absorbent body is intermittently fixed to the outer packaging material continuous body, and the absorbent article Provided is a method for producing a pants-type disposable absorbent article comprising a step of obtaining a continuous body, and a step of forming a side seal portion after cutting the absorbent article continuous body in half and cutting into individual absorbent articles. The eyes by It is those that have achieved.

  According to the manufacturing method of the pants-type disposable absorbent article of the present invention, the pants-type disposable absorbent article in which the waistline portion is well stretched in the absorbent article width direction using a belt-like sheet having elasticity in the width direction, Efficient continuous production is possible.

The present invention will be described below based on preferred embodiments with reference to the drawings.
First, the underpants type disposable diaper manufactured by the manufacturing method of this embodiment is demonstrated.
The perspective view of an example of the underpants type disposable diaper manufactured by the manufacturing method of this embodiment is shown by FIG. FIG. 2 shows a plan view of the developed state of the diaper of FIG. FIG. 3 shows a cross-sectional view taken along line II-II in FIG.

  The pants-type disposable diaper 1 shown in FIGS. 1 to 3 includes a liquid-permeable top sheet 2, a liquid-impermeable or water-repellent back sheet 3, and a liquid-retaining absorption disposed between both sheets 2 and 3. The absorbent body 4 is provided with a substantially vertically long absorbent body 10 and an outer packaging material 11 disposed on the back sheet 3 side of the absorbent body 10.

  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 outer packaging material 11 is divided in the longitudinal direction into an abdominal side A disposed on the wearer's abdominal side, a back side B disposed on the back side, and a crotch C positioned therebetween. The abdomen A and the back B correspond to the longitudinal front and rear ends of the outer packaging material 11, and the crotch C corresponds to the longitudinal center of the outer packaging material 11. The outer packaging material 11 has both side edges A1, A2 of the ventral side A and side edges B1, B2 of the back side B joined together, and the diaper 1 has a waist opening 5 and a pair of leg openings. 6 is formed. By this joining, a pair of side seal portions S, S are formed on the left and right side edges of the diaper 1.

  The top sheet 2, the back sheet 3, and the absorbent core 4 each have a rectangular shape, and 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. The absorbent main body 10 is bonded and fixed to the outer packaging material 11 via an adhesive 15.

  As shown in FIG. 2, side 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. Thereby, when the diaper 1 assembled as shown in FIG. 1 is worn, the side member cuff 8 stands up due to the elastic member 81 contracting, and the outflow of liquid in the width direction of the absorbent body 10 is prevented. Is done.

The outer packaging material 11 has a structure in which two sheets 12 and 13 are laminated, and the two sheets 12 and 13 are both extensible, and either one or both of them are stretchable. have. The extensibility is not limited as long as it is extensible in at least the width direction of the diaper (left-right direction in FIG. 2, also referred to as the diaper width direction) when the diaper is in the unfolded state. It is only necessary to have stretchability. Both of the two sheets 12 and 13 in the present embodiment can expand more in the diaper width direction than in the longitudinal direction of the diaper (vertical direction in FIG. 2). More specifically, it expands greatly in the diaper width direction and contracts after expansion, but slightly expands in the diaper longitudinal direction.
In the diaper 1 of the present embodiment, one sheet 12 forms the outer surface of the diaper 1, and the other sheet 13 is disposed on the inner surface side of the sheet 12.

As a sheet having elasticity, (1) a sheet in which an extensible fiber layer is integrated on both sides or one side of the elastic fiber layer, (2) can be extended on both sides or one side of a net-like elastic sheet A sheet in which a fiber layer is integrated, (3) a sheet in which an extensible fiber layer is integrated on both sides or one side of an elastic sheet made of an elastic film, and the like can be preferably used.
The stretchable sheets 12 and 13 may be stretchable and extensible sheets having the same configuration, or may be stretchable sheets having different configurations. In addition, as a method of integrating the elastic fiber layer and the extensible fiber layer, these are laminated and hydroentangled, or the fibers are entangled or fused by air-through, etc., heat embossing, adhesive The method of joining by ultrasonic waves etc. is mentioned.

  As the sheet of (1), for example, (a) a substantially inelastic non-elastic fiber layer is disposed on at least one surface of the elastic fiber layer, and both fiber layers have a fiber form of the constituent fibers of the elastic fiber layer. In a state where the fibers are joined together by thermal fusion at the fiber intersections, a part of the constituent fibers of the inelastic fiber layer has entered the elastic fiber layer and / or a part of the constituent fibers of the elastic fiber layer Stretchable non-woven fabric in a state in which it enters the inelastic fiber layer, and the sheets of (1) to (3) described above include (b) an elastic layer having elastic stretchability and a substantially inelastic nonelastic fiber A stretchable sheet or the like obtained by stretching a laminated sheet in which the two layers are laminated in the thickness direction and partially joined together can be preferably used.

The stretchable nonwoven fabric (a) will be described.
At the interface between the elastic fiber layer and the non-elastic fiber layer and in the vicinity thereof, the intersection of the constituent fiber of the elastic fiber layer and the constituent fiber of the non-elastic fiber layer is heat-sealed, and is substantially uniform over the entire surface. It is joined to. By joining all over, it is prevented that both layers are separated and a space is formed, and a stretchable nonwoven fabric having a multi-layer structure with a sense of unity, such as a single nonwoven fabric. "The state in which the constituent fibers of the elastic fiber layer maintain the fiber form" means that even if most of the constituent fibers of the elastic fiber layer are given heat, pressure, etc., a film or film-fiber structure The state which is not deformed. Further, in the elastic fiber layer, the intersections of the constituent fibers are thermally fused in the layer. Similarly, in the non-elastic fiber layer, the intersection of the constituent fibers is thermally fused in the layer.

  When non-elastic fiber layers are arranged on both sides of the elastic fiber layer, at least one of the constituent fibers is in a state in which a part of the constituent fibers enters the elastic fiber layer and / or the constituent fibers of the elastic fiber layer A part has entered into at least one of the inelastic fiber layers. In order to allow the constituent fibers of the non-elastic fiber layer to enter the elastic fiber layer and / or to allow the constituent fibers of the elastic fiber layer to enter the non-elastic fiber layer, the constituent fibers of the non-elastic fiber layer and the non-elastic fiber layer It is preferable that at least one of the non-elastic fiber and the elastic fiber is in a web state (a state where the fiber is not heat-sealed) before the process of thermally fusing the constituent fibers. From the viewpoint of allowing the constituent fibers to enter other layers, the fiber layer in the web state is preferable because the short fibers have a higher degree of freedom than the long fibers. Moreover, it is preferable to use the air-through method in order to allow the constituent fibers of the non-elastic fiber layer to enter the elastic fiber layer and / or to allow the constituent fibers of the elastic fiber layer to enter the non-elastic fiber layer. By using the air-through method, the constituent fibers can be made to enter the opposing fiber layer, and the constituent fibers can be easily made to enter from the opposing fiber layer. In addition, by using the air-through method, it becomes easy to allow the constituent fibers of the inelastic fiber layer to enter the elastic fiber layer while maintaining the bulkiness of the inelastic fiber layer. In particular, when the constituent fibers of the inelastic fiber layer are entangled with the constituent fibers of the elastic fiber layer, it is preferable that they are entangled only by the air-through method. In order to entangle the fibers by the air-through method, the gas blowing pressure, the blowing speed, the basis weight and thickness of the fiber layer, the conveyance speed of the fiber layer, etc. may be adjusted appropriately. It is preferable to carry out the method. In the hot air treatment (particularly, the air-through method), a part of the constituent fibers of the non-elastic fiber web enters the elastic fiber web, and at the same time, the constituent fibers of the non-elastic fiber web and / or the constituent fibers of the non-elastic fiber web; The constituent fibers of the elastic fiber web are heat-sealed at their intersections. In this case, care should be taken so that the constituent fibers of the elastic fiber web do not become a film or a film-fiber structure by hot air treatment.

  The elastic fiber layer has the property of being stretchable and contracting when released from the stretched force. The elastic fiber layer preferably has a residual strain of 20% or less, particularly 10% or less when contracted after 100% elongation in at least one direction parallel to the surface. This value is preferably satisfied in at least one of the MD direction and the CD direction, and more preferably satisfied in both directions.

  The elastic fiber layer is an aggregate of fibers having elasticity. The elastic fiber forming method includes, for example, a melt blown method in which a molten resin is extruded from a nozzle hole, and the extruded molten resin is elongated by hot air to thin the fiber, and a semi-molten resin is cooled by cold air. There is a spunbond method in which stretching is performed by a mechanical draw ratio. As a special method of the melt blown method, there is a spinning blow method in which the spun bond method is combined with the melt blown method. The elastic fiber layer may be in the form of a web or a nonwoven fabric made of elastic fibers. For example, it may be a web or a non-woven fabric formed by a spinning blow method, a spun bond method, a melt blow method, or the like. Particularly preferred is a web obtained by the spinning blow method. As the constituent fiber of the elastic fiber layer, for example, a fiber made of thermoplastic elastomer, rubber or the like can be used. In particular, fibers made from thermoplastic elastomers can be melt-spun using an extruder in the same way as ordinary thermoplastic resins, and the fibers thus obtained are easily heat-sealed. Is suitable for the stretchable nonwoven fabric of this embodiment. Examples of the thermoplastic elastomer include styrene elastomers such as SBS, SIS, SEBS, and SEPS, olefin elastomers, polyester elastomers, and polyurethane elastomers. These can be used individually by 1 type or in combination of 2 or more types.

  The inelastic fiber layer has extensibility but is substantially inelastic. The stretchability here 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 fibers are separated from each other, or the fibers are thermally fused. The three-dimensional structure formed by a plurality of fibers may be structurally changed due to wearing or the like, and the constituent fibers may be broken, and the whole fiber layer may be elongated. Examples of the fibers constituting the inelastic fiber layer include fibers made of polyethylene (PE), polypropylene (PP), polyester (PET or PBT), polyamide, and the like. The fibers constituting the inelastic fiber layer may be short fibers or long fibers, and may be hydrophilic or water repellent. Further, core-sheath type or side-by-side composite fibers, split fibers, irregularly shaped cross-section fibers, crimped fibers, heat-shrinkable fibers, and the like can also be used. These fibers can be used singly or in combination of two or more. The inelastic fiber layer can be a continuous filament or short fiber web or nonwoven.

The stretchable sheet (b) will be described.
An elastic sheet is a laminated sheet in which substantially non-elastic non-elastic fiber layers are laminated on both sides or one side of an elastic layer having elastic elasticity, and these are partly joined in a regular pattern. It can be obtained by subjecting it to stretching.

  For example, the laminated sheet used for the production of the stretchable sheet forms an elastic layer by supplying elastic fibers on a fiber web (first inelastic fiber layer) supplied from a card machine, and further on the elastic layer. , Supplying other card machines or fiber webs (second non-elastic fiber layer) 2), and subjecting the resulting laminated sheet of the three-layer structure to hot air treatment using an air-through dryer, The laminated sheet is subjected to hot embossing by an embossing device including an embossing roll in which embossing convex portions are regularly arranged on the peripheral surface and an anvil roll arranged to face the embossing roll. The hot air treatment by the dryer is performed for the purpose of heat fusion between the elastic fiber and the non-elastic fiber and the entry of the fiber, but such hot air treatment can be omitted.

  The elastic layer preferably includes elastic fibers made of an elastic material. Examples of the elastic material include thermoplastic elastomers, rubbers, ethylene / propylene copolymers, and the like. Among these, thermoplastic elastomers are preferable because a fibrous elastic body can be formed relatively easily. 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. The content of elastic fibers made of an elastic material in the elastic layer is preferably 50 to 100% by weight, particularly 75 to 100% by weight. 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.

  The inelastic fiber layer is extensible but substantially inelastic. The stretchability here 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 fibers are separated from each other, or the fibers are thermally fused. Any of the cases where the three-dimensional structure formed by a plurality of fibers is structurally changed by wearing or the constituent fibers are broken and stretched as a fiber layer. Examples of the fibers constituting the inelastic fiber layer include fibers made of biodegradable resins such as polyethylene, polypropylene, polyester (PET and PBT), nylon, and 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 also be used. These fibers can be used singly or in combination of two or more.

As the sheet having stretchability, various known ones can also be used. For example, a nonwoven fabric made of a mixed fiber containing fibers made of a thermoplastic polyurethane elastomer described in JP-A-2004-244791 can be used. A stretchable composite nonwoven fabric described in Japanese Patent No. 512313, a sheet described as a “stretchable satellite article surface sheet” in Japanese Patent Laid-Open No. 3-269145, an elastic stretchable composite sheet described in Japanese Patent Laid-Open No. 2001-18315, A stretchable composite nonwoven fabric described in Japanese Patent Application Laid-Open No. 2001-140158, a composite elastic nonwoven fabric described in Japanese Patent Application Laid-Open No. 9-500936, a laminated sheet described in Japanese Patent Application Laid-Open No. 10-29259, and the like can also be used.
Moreover, as a sheet | seat which has extensibility but does not have a stretching property, the thing etc. which are described in Japanese Patent Publication No. 8-508789 gazette, Japanese translation gazette 2000-513054 gazette, etc. can be used.

  In the pants-type disposable diaper 1, as shown in FIG. 3, between the two sheets 12 and 13 constituting the outer packaging material, heat sealing, high frequency sealing or ultrasonic waves are provided in the side seal portions A1, A2, B1 and B2. The hot melt type is joined to each other by a seal, at the peripheral portion 50 of the waist opening 5 and the peripheral portion 60 of each of the pair of leg openings 6 and the central portion in the diaper width direction extending from the ventral side A to the back side B. They are joined together by an adhesive 14 such as an adhesive.

  A plurality of waist elastic members 51, 51 are arranged on the peripheral edge 50 of the waist opening along the opening peripheral edge of the waist opening. These waist elastic members 51 and 51 are fixed in an extended state between the two sheets 12 and 13 via an adhesive. Leg part elastic members 61a and 61b are also arranged along the peripheral edge of each opening part in the peripheral part 60 and 60 of the leg opening part. These leg elastic members 61a and 61b are also fixed in an extended state between the two sheets 12 and 13 via an adhesive. Elastic material such as natural rubber, polyurethane resin, foamed urethane resin, hot melt elastic member, etc. is formed into a thread (thread rubber) or a belt (flat rubber) for the waist elastic member and leg elastic member, respectively. What has been used is preferably used.

  In the pants-type disposable diaper 1, the sheets 12 and 13 constituting the outer packaging material 11 have a length that extends beyond a portion where the waist elastic members 51 and 51 are sandwiched and fixed as shown in FIG. 2. The extended portion is integrally folded toward the absorbent main body 10 at the opening peripheral edges 5a and 5b of the waist opening. The skin contact surface side at both longitudinal ends of the absorbent main body 10 is covered and bonded to the folded portions 12 a and 12 b of the sheets 12 and 13, whereby both longitudinal ends of the absorbent main body 10 are bonded. The part is fixed to the outer packaging material 11.

Next, a preferable method for continuously producing the above-described pants-type disposable diaper 1 will be described with reference to FIGS.
First, as shown in FIG. 4, as a belt-like sheet having stretchability in the width direction, a belt-like sheet 120 that stretches in the width direction but hardly stretches or stretches in the longitudinal direction is publicly known from a roll-shaped raw fabric. It is fed out by a mechanism and transported by a known transport mechanism. And in the position shown by arrow P1 in a conveyance path, the strip | belt-shaped sheet | seat 120 is cut | disconnected over the width direction by a predetermined space | interval. Various known cutting means such as a roller cutter and a laser cutter can be used for cutting. The belt-like sheet 120 is a sheet arranged on the outer surface side of the diaper of the two sheets 12 and 13 constituting the outer packaging material 11.
Next, the short object 121 generated by intermittent cutting of the belt-like sheet 120 is rotated 90 degrees as indicated by an arrow P2, and the expansion / contraction direction of the short object 121 (the direction indicated by the white arrow in FIG. 4) is changed. Turn to the machine direction. This rotation is performed for each short object 121 that is sequentially generated by intermittent cutting.
As shown in FIGS. 5 and 6, the short object 122 rotated 90 degrees is arranged so that the end parts 122 a and 122 b in the flow direction overlap each other. Then, the overlapping portion 127 is subjected to processing such as heat sealing, ultrasonic sealing, and high frequency sealing, and the adjacent short objects 122 are connected to each other. FIG. 5 shows a state in which the strip 122 after the belt-like sheet 120 is cut by the cutter blade 123 and rotated 90 degrees is connected by the heat seal 124 having a dot pattern.

The sealing process for connecting the short objects 122 is not limited to the one that forms the joint portion of the dot pattern, and various patterns can be adopted. However, the connection of the short objects 122 is as shown in FIG. In the overlapping direction (hereinafter also referred to as a laminated portion) 127 of the end portions 122a and 122b of the short objects 122 and 122 adjacent to each other in the flow direction, a large number of joint portions 124 are formed in the same direction as the width direction of the belt-like sheet 126. , 124... Are preferably applied with a sealing process so that they are intermittently formed.
In FIG. 7, by providing convex portions 42 having a specific form and arrangement on the peripheral surface of the uneven roll 41 of the heat seal device 40, a large number of joints are formed on the overlapping portion 127 between the ends of the adjacent short objects 122. A state of forming the portion (thermal fusion portion) 124 is shown.
Examples of the shape of each joint portion 124 include a linear shape, a circular shape, a rectangular shape, and an oval shape.

  The individual joints 124 are also preferably elongated. When the individual joints have an elongated shape, the longitudinal center line L1 (the center line extending in the longitudinal direction, see FIG. 8A) is inclined with respect to the longitudinal direction X of the belt-like sheet 126. preferable. The inclination angle θ [see FIG. 8A] of the joint portion 124 with respect to the longitudinal direction of the belt-like sheet can be set to 15 to 60 °, for example. In addition, the ratio of the length L to the width W (L / W) of the elongated joint is preferably 1.3 or more, and the ratio is preferably 2 to 10.

As a preferable arrangement pattern when a large number of joints 124, 124,... Are formed intermittently in the width direction of the belt-like sheet 126, for example, arrangement patterns as shown in FIGS. .
In the arrangement pattern shown in FIG. 8A, the elongated joining portions 124 are intermittent in the width direction (Y direction) of the belt-like sheet 126 in a state where the elongated joining portions 124 are inclined in the longitudinal direction (X direction) of the belt-like sheet 126. Are arranged. In FIG. 8B, similarly, a large number of elongated joining portions 124 are arranged in the width direction (Y of the belt-like sheet 126 in a state in which the respective longitudinal directions coincide with the width direction (Y direction) of the belt-like sheet 126. In the direction).
It is preferable that the minimum distance L2 between the joint portions 124 and 124 adjacent in the width direction of the belt-like sheet 126 is larger than the width W of each joint portion 124.

  In the joint arrangement pattern shown in FIG. 8C, circular joints 124, 124,... Are intermittently arranged in the Y direction. More specifically, three rows of junctions in which a large number of junctions are intermittently arranged in series in the Y direction are formed in three rows in the X direction, and adjacent junction rows are positions of the junctions in the Y direction. Is shifted by half a pitch. Thus, when there are a plurality of joint rows, it is preferable that the minimum distance L2 between the adjacent joints, including the joints in the adjacent joint rows, is larger than the width W of each joint. In place of the circular joint shown in FIG. 8C, other isotropic properties such as a square, an equilateral triangle, an ellipse having a minor axis to major axis ratio (major axis / minor axis) of less than 1/3, etc. A shape can also be adopted. The width W in the case of an isotropic shape is the length of the diameter in the case of a circle, the long diameter in the case of an ellipse, and the center point of the area of the joint in plan view in other cases. Is a distance between the intersection points when the distance between the two intersections at which the straight line intersects the periphery of the joint is minimized when the straight line passing through is rotated 360 degrees with the center point as the rotation axis. .

By forming the joining portion 124 by heat sealing or the like on the laminated portion 127 between the end portions of the sheet-like short material (hereinafter also referred to as a short sheet) 122, the short materials 122 are connected to each other, and the longitudinal direction is longer than the width direction. The belt-like sheet 126 having higher extensibility is obtained.
When joining the end portions of the short sheet 122, as described above, when a large number of joining portions are joined and connected so as to be arranged intermittently in the width direction of the belt-like sheet 126, the obtained belt-like sheet 126 is obtained. Wrinkle-like wrinkles generated when extending in the longitudinal direction can be reduced.
If wrinkles occur in the elongated belt-like sheet, in the subsequent process, other members (such as other belt-like sheets) are joined to the belt-like sheet, or the accuracy when cutting the belt-like sheet is reduced. The final product may be adversely affected such as deterioration in appearance.
The wrinkles generated in the stretched strip sheet are likely to occur when the material constituting the strip sheet is a material that contracts in the width direction when the strip sheet is stretched in the longitudinal direction. This is caused by buckling or deformation of the joining portion 124 without contracting, while attempting to contract in the width direction.
Therefore, the above-described wrinkle-preventing effect obtained by sealing with a pattern in which a large number of joints 124, 124,... Are intermittently formed in the width direction of the belt-like sheet 126 is the same as that before extending in the longitudinal direction. This is effective for producing a belt-like sheet having a width Wb of less than 100%, particularly 50 to 90% when the elongation is 100% in the longitudinal direction with respect to the width Wa.

Since the wrinkles described above are produced by stretching the belt-like sheet, the above-described wrinkle generation suppressing effect is particularly useful when the belt-like sheet is stretched to an elongation rate of 40% or more in a later step. Yes, it is more useful when stretched to a stretch rate of 70 to 150%.
In particular, the fact that there is no wrinkle when joining to other members in such a stretched state has the advantage that it can be joined accurately at the place to be joined, and the state after joining is also beautiful. is there. In addition, the fact that no wrinkle is generated when cutting in a state of being stretched at such an elongation rate has the advantage that it can be cut with high precision at the locations to be joined, and the cut end is clean.

From the viewpoint of more surely preventing the occurrence of wrinkles, it is preferable that the shortest distance L2 of the large number of joining portions (thermal fusion portions) 124 formed in the laminated portion 127 is 4 mm or more.
Moreover, it is preferable to have between the joining parts 124 and 124 adjacent in the width direction of the strip | belt-shaped sheet | seat 126, the non-joining part (gap which does not have a junction part) continuous in the longitudinal direction of a strip | belt-shaped sheet | seat.

  Further, the upper limit value of the shortest distance L2 is not particularly limited, but the joining state in the width direction (Y direction) of the belt-like sheet 126 is made uniform to prevent the end portion of the short sheet 122 from being pulled in the longitudinal direction when stretched. From the viewpoint of doing, it is preferably 30 mm or less, and more preferably 10 mm or less.

  For example, as shown in FIG. 8A, the longitudinal direction of the belt-like sheet is determined on whether or not it has a non-joint portion continuous in the longitudinal direction of the belt-like sheet between the adjacent joint portions 124, 124. Assuming a straight line LX parallel to the (X direction), when the straight line LX is translated in the width direction (Y direction) of the belt-like sheet, it is between the joints 124 adjacent to each other in the Y direction. This can be determined by whether or not there is a region where the straight line LX does not overlap any joint. For example, in the bonding portion arrangement patterns shown in FIGS. 8A to 8C, there is a region of width L <b> 3 where the bonding portion 124 does not exist across the entire width of the stacked portion 127 between the bonding portions. In that region, since the straight line LX does not overlap any of the joining portions, there is a non-joining portion that is continuous in the longitudinal direction of the belt-like sheet between the neighboring joining portions.

As a method (or mechanism) for rotating the short object 121 by 90 degrees, known rotating devices described in JP-A-63-52824, JP-A-3-226411, and JP-A-3145371 can be used.
As a method of filling the pitches of the short objects 121 after being rotated by 90 degrees and overlapping the ends in the flow direction of adjacent short objects, the single objects 122 after being rotated by 90 degrees are alternately different. A single object 122B conveyed by two conveyance paths, and arranged on a continuous conveyance means such as a belt conveyor with a single object 122A conveyed by one conveyance path, and is conveyed by the other conveyance path. Can be used such that both end portions 122b and 122b overlap end portions 122a of the front and rear single objects 122A on the same continuous conveying means.
One conveyance path and the other conveyance path rotate while adsorbing the single object 122 on the peripheral surface, and the single object is received at a predetermined position on the peripheral surface by the control of the adsorption. It can be composed of a suction roll that can be detached from the surface, or a combination of this with a known conveying means such as a belt conveyor. The peripheral surface of the suction roll may be composed of a plurality of suction heads.

Moreover, as shown in FIG. 5, the method of using the carrier material 125 can be mentioned as a receiving material after the edge parts of the adjacent short thing in the flow direction are overlapped. As the carrier material 125, an extensible sheet and a non-stretchable sheet described in the present specification can be used. Examples of means for joining the carrier material and the elongated sheet include a method of joining each other by heat sealing, high frequency sealing or ultrasonic sealing, a method of applying a hot melt between the carrier material and the elongated sheet, and preferably joining, It is possible to do both. As for the non-stretch sheet, for example, air-through nonwoven fabric, heat roll nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, meltblown nonwoven fabric, nonwoven fabric by various manufacturing methods, woven fabric, knitted fabric, resin film, etc., and these two or more are laminated and integrated The sheet | seat material etc. which are made can be used.
In addition, as an aspect which overlaps the edge parts of the short object 122 after rotating 90 degree | times, as shown in FIG. 6, it is preferable to overlap the edge part of the short object 122 up and down alternately toward a machine direction.

In this way, the short object 121 generated by cutting is rotated by 90 degrees and then connected, so that the belt-like sheet having the machine direction stretchability expands and contracts in the machine direction but almost expands and contracts in the width direction. A belt-like sheet 126 that does not stretch is obtained.
In the present embodiment, as shown in FIG. 4, the sheet 13 disposed on the absorbent main body 10 side of the two sheets 12 and 13 constituting the outer packaging material 11 also expands and contracts in the width direction. Using a belt-like sheet 130 (a belt-like sheet having stretchability in the width direction) 130 that hardly expands or contracts in the machine direction, the belt-like sheet 130 is cut at a predetermined position (position indicated by an arrow P3) in the conveyance path. The resulting short object 131 is rotated 90 degrees and then connected to obtain a belt-like sheet 136 having machine direction stretchability. Cutting, rotation, and connection of the belt-like sheet 130 can be performed in the same manner as the belt-like sheet 120.

  Next, the two belt-like sheets 126, 136 having the machine direction stretchability obtained as described above are bonded together so as to sandwich the leg elastic members 61a, 61b and the waist elastic member 51 between them, An outer packaging material continuum 110 is obtained. Specifically, before the two belt-like sheets 126 and 136 are overlapped, an adhesive for fixing the elastic member is applied to a predetermined portion of one or both of the two belt-like sheets. The belt-shaped sheets 126 and 136 are narrowly pressed by the nip roll 7 to fix the elastic member in a state where the elastic member is sandwiched, and the belt-shaped sheets 126 and 136 are joined together. The leg elastic members 61a and 61b are introduced and fixed between the belt-like sheets 126 while being swung by a known rocking guide in a direction perpendicular to the machine direction of the belt-like sheets 126 and 136.

The pants-type disposable diaper 1 described above can be obtained in the same manner as the so-called transverse flow type pants-type disposable diaper manufacturing method, except that the outer packaging material continuum 110 thus obtained is used.
Specifically, for example, as shown in FIG. 4, after the trim 111 for leg opening formation is removed from the outer packaging material continuous body 110 by a rotary cutter or the like, the separately manufactured absorbent main body continuous body is cut. The absorbent main body 10 obtained in this manner is rotated by 90 degrees, and is intermittently bonded and fixed on the outer packaging material continuum 110 to obtain a diaper continuum 100. Both sides of the outer wrapping material continuum 110 in the diaper continuous body 100 The portions 12a and 12b are folded back so as to cover both end portions of the absorbent main body 10, and the both end portions are further fixed. Then, the diaper continuous body 100 is folded in two, and then the side seal portions S and S are heat sealed. A pants-type disposable diaper can be obtained after being formed by ultrasonic sealing, high-frequency sealing, or the like, or simultaneously with forming the side seal portions S, S, by cutting into individual diapers. In addition, as a method of rotating the absorptive main body 10 90 degree | times and fixing intermittently on the outer packaging material continuous body 110, the method of patent document 1 can be used, for example.

  According to the manufacturing method of the pants-type disposable diaper of the present embodiment, the pants-type disposable in which the waistline portion expands and contracts well in the diaper width direction using the belt-like sheet 120.130 having extensibility in the width direction in this way. Diapers can be produced efficiently and continuously. Moreover, desired shrinkage | contraction performance can be provided to the peripheral part of a waist opening part and a leg opening part by elastic member 61a, 61b, 51. FIG.

As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment, It can change suitably.
For example, any one of the two sheets 12 and 13 in the pants-type disposable diaper 1 may not have elasticity. For example, the extensible sheet 13 disposed on the absorbent main body 10 side of the sheets 12 and 13 may be extensible but not expandable. This pants-type disposable diaper is obtained as described above without using a belt-like sheet having extensibility in the machine direction instead of the belt-like sheet 130 described above as a raw fabric of the stretchable sheet 13 and rotating it by 90 degrees. In addition, continuous production can be performed in the same manner as in the above embodiment except that a continuous outer packaging material obtained by pasting the belt-like sheet 126 having stretchability in the machine direction is used.
Further, instead of fixing the leg elastic members 61a and 61b and the waist elastic member 51 along the flow direction of the two belt-like sheets between the belt-like sheet 126 and the belt-like sheet 136, the leg elastic member 61a 61b and the waist elastic member 51 can be fixed.
Moreover, the strip | belt-shaped sheet | seats 120 and 130 which have a width direction elastic property may replace with what was drawn out from the roll-shaped original fabric, and may be continuously manufactured upstream of the diaper manufacturing line.

Furthermore, as a method of obtaining a belt-like sheet having a machine direction stretchability from a belt-like sheet having a width direction stretchability, as shown in FIGS. 9 and 10, two beltlike sheets 120A and 120B each having a width direction stretchability are used. Is used as an original fabric, these belt-like sheets are cut intermittently, and the resulting short articles 121A and 121B are respectively rotated 90 degrees, and then the short article 122A ′ produced from one of the belt-like sheets 120A and the other belt-like sheet It is also possible to use a method in which short objects 122B ′ generated from the sheet 120B are alternately arranged and connected to form a single belt-like sheet having stretchability in the machine direction. In this case, the ends of the short objects 122A ′ and 122B ′ after being rotated by 90 degrees overlap as shown in FIG.
Moreover, the same method can be used also about the method of obtaining the strip | belt sheet which has a machine direction extensibility from the strip | belt-shaped sheet | seat which has the width direction extensibility.

  In addition, the description omitted in one embodiment and the requirements of only one embodiment can be applied to other embodiments as appropriate, and the requirements in each embodiment can be appropriately applied between the embodiments. Can be substituted for each other. The method for producing a disposable absorbent article of the present invention can also be used for a method for producing a pants-type sanitary napkin.

It is a perspective view which shows an example of the underpants type disposable diaper manufactured by the manufacturing method of the underpants type disposable diaper 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 schematic diagram which shows the outline of the manufacturing process of a pants-type disposable diaper. It is a schematic diagram which shows the detail of 1 process of a manufacturing process of a pants-type disposable diaper. It is a side view from the arrow D direction in FIG. 5 of the strip | belt-shaped sheet | seat which has a machine direction elasticity. It is a perspective view which shows the preferable example of the method of connecting a short thing and re-forming to a strip | belt-shaped sheet | seat. It is a top view which shows the arrangement | positioning pattern of the preferable junction part at the time of connecting a short thing by sealing. FIG. 6 is a view corresponding to FIG. 5 in another embodiment. It is the side view which looked at the strip | belt-shaped sheet | seat which has the machine direction elasticity in the embodiment shown in FIG. 7 from the arrow D direction in FIG.

Explanation of symbols

1 Pants-type disposable diapers (pants-type disposable absorbent articles)
2 Top sheet 3 Back sheet 4 Absorbent core 5 Waist opening 6 Leg opening 10 Absorbent body 11 Outer packaging material 12, 13 Stretchable sheet 120, 130 Band-shaped sheet 126,136 with stretch in width direction Stretch in machine direction Belt-like sheet 110 having outer properties 110 wrapping material continuum 100 diaper continuum

Claims (3)

A method for producing a pants-type disposable absorbent article comprising an absorbent body including an absorbent core and an outer packaging material,
The belt-like sheet having the stretchability in the width direction is cut intermittently, and the short sheet produced by the cutting is rotated 90 degrees and then connected to form a belt-like sheet having the machine direction stretchability. Obtaining step,
Bonding the belt-like sheet having a machine direction stretchability and another belt-like sheet having a machine direction stretchability so as to sandwich an elastic member therebetween to obtain a continuous outer packaging material,
Steps of intermittently fixing the absorbent main body to the outer packaging material continuum to obtain an absorbent article continuum; and
A method for producing a pants-type disposable absorbent article, comprising: folding the absorbent article continuous body in half, forming a side seal portion, and cutting the absorbent article continuous article into individual absorbent articles.   The another belt-like sheet having extensibility in the machine direction is obtained by intermittently cutting the belt-like sheet that is continuously conveyed, and connecting the short objects generated by the cutting after rotating by 90 degrees. The manufacturing method of the underpants type disposable absorbent article of description. The connection is performed by performing sealing so that the ends of adjacent short objects overlap each other, and a large number of joints are intermittently formed in the overlapping portion in the same direction as the width direction of the belt-like sheet. The manufacturing method of the underpants type disposable absorbent article of Claim 1 to perform.

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