JP7296301B2 - Absorbent manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing an absorbent body for use in absorbent articles such as disposable diapers and sanitary napkins.

2. Description of the Related Art In production lines for products such as disposable diapers and sanitary napkins, a folding device is used to fold back sheets such as nonwoven fabrics and resin films that are continuously conveyed. This folding device typically includes a conveyer that conveys a sheet placed on a conveying surface, and a side edge along the conveying direction of the sheet conveyed by the conveyer that is folded back in a direction orthogonal to the conveying direction. and a folding guide. Further, as the folding device, there is known one that includes a suction mechanism that performs a suction operation for bringing the sheet on the conveying surface into close contact with the conveying surface.

Patent Literatures 1 and 2 describe a method of manufacturing an absorbent body using a folding device having such a configuration. In such a method for manufacturing an absorbent body, a covering sheet called a core wrap sheet is placed on the conveying surface of the folding device, and an absorbent core is further placed on the sheet, and the absorbent core is spread through the conveying surface. The absorbent core is covered with the sheet by folding back each side region along the conveying direction of the sheet in a direction orthogonal to the conveying direction while sucking the sheet with the pliers.

JP 2016-97172 A Japanese Patent Application Laid-Open No. 2010-240110

FIG. 8 of the present application shows an example of an absorbent body manufacturing method using a conventional folding device. The folding device 90 shown in FIG. 8( a ) includes an air-permeable conveying conveyor 91 forming a conveying surface and a folding guide 92 . The suction force V allows the objects to be conveyed (the absorbent core 95 and the core wrap sheet 96) on the conveying surface to be conveyed while being attracted to the conveying surface. The turn-back guides 92 are arranged along both side edges of the conveyer 91 along the conveying direction (MD), and have a pair of side wall portions 93 having portions positioned above the conveyer 91 (same plane as the conveying surface). , 93, and a pair of extending portions 94, 94 extending from the pair of side wall portions 93, 93 inward in the direction perpendicular to the transport direction (CD) perpendicular to the MD. Moreover, as shown in FIG. 8(b), the absorbent core 95 covered with the core wrap sheet 96 by the folding device 90 has different lengths (widths) of the CD along the MD. has a narrowest portion where the length of CD is the shortest, and both side edges of the narrowest portion along MD are constricted portions N.

In the folding device 90, the extending portions 96E of the core wrap sheet 96 extending outward from the CD from both side edges 95S along the MD of the absorbent core 95 are folded along the folding lines along the MD, and the absorbent core When the core wrap sheet 96 is folded to cover the upper surface of the core wrap sheet 95 (the surface opposite to the surface facing the conveyer 91) at a position other than the constricted portion N, the absorbent Since the extending portion 96E is folded back at the folding line located near the side edge 95S of the core 95, the core wrap sheet 96 (on which the absorbent core 95 is placed) located inside the CD with the folding line as the boundary is folded. The absorbent core 95 is interposed between the core wrap sheet 96) and the extending portion 96E located outside the CD, so that the suction force V is less likely to act on the extending portion 96E, and the extending portion 96E can be smoothly folded back to the upper surface side of the absorbent core 95. - 特許庁On the other hand, when the core wrap sheet 96 is folded back at the constricted portion N, as shown in FIG. Since it is located outside the CD from the side edge 95S, the suction force V generated outside the CD from the side edge 95S is likely to act on the extension 96E. There is a problem that wrinkles S are generated in the core wrap sheet 96 (extending portion 96E) due to adsorption. In addition, when the extending portion 96E sticks to the conveyer 91 in this way, it becomes difficult to completely cover the upper surface of the absorbent core 95 with the extending portion 96E. There was a problem that the opening of the mouth occurred.

In addition, as shown in FIG. 8(a), the area where the folding guide 92 is arranged is covered by a pair of air-impermeable extending portions 94, 94 constituting the folding guide 92 above the conveyer 91. The pair of extensions 94, 94 are partially overlapped with a small gap therebetween. Air flow A flows in from the air-permeable core wrap sheet 96 and directly hits the absorbent core 95 through the core wrap sheet 96. As a result, problems such as falling off of the material forming the absorbent core 95 and loss of shape of the absorbent core 95 are caused. there were.

An object of the present invention is to improve a manufacturing method of an absorbent body. To provide a method for successfully covering an absorbent core with a sheet.

In the present invention, a core wrap sheet having an absorbent core laminated thereon is placed as the object to be conveyed on the conveying surface of a conveying means capable of conveying the object on the conveying surface while sucking the object, and suction is performed. The conveyed object is conveyed by moving the conveying surface in one direction while carrying out, and during the conveying, the core wrap sheet is perpendicular to the conveying direction from both side edges along the conveying direction of the absorbent core. A covering step of folding back the extending portion extending outward in the direction perpendicular to the conveying direction so as to cover the upper surface of the absorbent core using a folding guide arranged along the conveying direction above the conveying surface. , wherein the absorbent core has different lengths in the direction orthogonal to transport along the direction of transport, and the length in the direction orthogonal to transport is the shortest part The conveying surface, which has a narrow width portion and moves in the area where the folding guide is arranged, is defined by a pair of imaginary straight lines extending in the conveying direction through both ends of the narrowest portion in the conveying orthogonal direction as boundaries. It is divided into a central area sandwiched between a pair of imaginary straight lines and side areas positioned on both sides of the conveying orthogonal direction across the central area, and the attraction force of the side areas is equal to the attraction force of the central area. It is a manufacturing method of the absorber which makes it low compared.

According to the present invention, an absorbent body in which an absorbent core is reliably covered with a core wrap sheet is provided without wrinkling the core wrap sheet and without falling off or losing shape of the material forming the absorbent core. can be manufactured.

FIG. 1 is a diagram schematically showing a cross section along the width direction of an example of an absorbent body manufactured by the manufacturing method of the present invention, and FIG. FIG. 1(b) is a cross-sectional view of the constricted portion of the absorbent body. FIG. 2 is a general schematic diagram showing an apparatus that can be used to carry out the manufacturing method of the present invention. FIG. 3 shows the apparatus shown in FIG. 2, in which an absorbent core is placed on a core wrap sheet being conveyed, and further, an extension of the core wrap sheet from the absorbent core is an upper surface of the absorbent core. It is a top view which shows typically a mode that it folds back to the side. FIG. 4 is a diagram schematically showing a cross section of the absorber taken along line II of FIG. 5 is a schematic perspective view of a folding device included in the device shown in FIG. 2. FIG. 6 is a schematic top view of the main part of the folding device shown in FIG. 2. FIG. FIG. 7 is a diagram showing an example of a method of manufacturing an absorbent body carried out by the folding device shown in FIG. 2, and is a cross-sectional view schematically showing a cross section along the direction orthogonal to conveyance. FIG. 8(a) is a view showing an example of a method for manufacturing an absorbent body using a conventional folding device, and is a cross-sectional view schematically showing a cross section along the direction perpendicular to the transport; 8A is a schematic perspective view of the absorbent core shown in FIG. 8(a). FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described based on its preferred embodiments with reference to the drawings. In addition, in the following description of the drawings, the same or similar reference numerals are given to the same or similar parts. The drawings are basically schematic, and the ratio of each dimension may differ from the actual one.

FIG. 1 shows an absorbent body 1 which is an example of an absorbent body which is a manufacturing object of the manufacturing method of the present invention, and FIGS. 2 and 3 show an absorbent body which is an embodiment of the manufacturing method of the present invention. 1 is outlined. The absorbent body 1 comprises an absorbent core 50 made of at least a fibrous material and a core wrap sheet 51 covering the absorbent core 50 . The absorbent core 50 is oriented in a direction orthogonal to the transport direction (hereinafter also referred to as "MD", which is an abbreviation for Machine Direction) at the time of manufacturing the absorbent body 1 (hereinafter also referred to as "CD", Cross Machine Direction ) varies along the MD with a narrowest portion 50N where the length of the CD is the smallest.

As shown in FIG. 3, the absorbent core 50 of this embodiment has a long shape in the MD, the longitudinal direction of which corresponds to the MD, and the width direction of which corresponds to the CD. The absorbent core 50 also has a narrowest portion 50N at a position that is biased toward one side of the MD (the wearer's ventral side when incorporated into an absorbent article) from the center of the MD. Both side edges 50S, 50S along the MD of the absorbent core 50 are curved toward the inside of the CD at the position of the narrowest portion 50N to form a constricted portion N.

The core wrap sheet 51 of the present embodiment is, as shown in FIG. It has a width that is two to three times the width of the core 50 . In the absorbent body 1, the wide core wrap sheet 51 covers the entire area of one surface of the absorbent core 50 (the lower surface facing the conveyor belt 42 when the absorbent body 1 is manufactured). The pair of extending portions 51E, 51E are folded back to the other surface of the absorbent core 50 (the upper surface when the absorbent body 1 is manufactured). Further, the tip portions of the pair of folded extending portions 51E, 51E overlap each other at the central portion of the upper surface of the absorbent core 50 to form an overlapping portion 52. As shown in FIG. As a result, the absorbent core 50 is covered with the core wrap sheet 51 at least on its upper and lower surfaces and each of its side surfaces.

As shown in FIGS. 2 and 3, the manufacturing method of the absorbent body 1 includes, as the object to be conveyed, an absorbent core on the conveying surface of a conveying means capable of sucking and conveying the object on the conveying surface. A core wrap sheet 51 on which 50 is laminated is placed, and the conveying surface is moved in one direction while performing suction (that is, the conveying object is sucked to the conveying surface), thereby conveying the conveyed object. and during its transportation, the core wrap sheet 51 extends outward in the transportation orthogonal direction (CD) orthogonal to the MD from both side edges 50S, 50S along the transportation direction (MD) of the absorbent core 50 There is a covering step of folding back the extending portion 51E so as to cover the upper surface of the absorbent core 50 using a folding guide 43b arranged along the MD above the conveying surface. A manufacturing apparatus 10 shown in FIG. 2 is preferably used for carrying out the manufacturing method of the absorbent body 1, and includes a fiber stacking section 20, a transfer section 30, and a folding section 40. As shown in FIG. The covering step is performed at the folding section 40 , and the conveying surface is the upper surface of the conveyor belt 42 forming the folding section 40 .

The fiber stacking portion 20 includes a fiber stacking drum 21 having a plurality of stacking recesses (not shown) formed at predetermined intervals on the outer peripheral surface 21S, and a material forming the absorbent core 50 (hereinafter also referred to as "core forming material"). ) and absorbent particles (eg, water-absorbent polymer particles) are supplied to the outer peripheral surface of the fiber stacking drum 21 along with the air flow. The duct 22 has one end 22a covering part of the outer peripheral surface 21S of the fiber stacking drum 21 and the other end 22b connected to the fiber material introducing device 23 for introducing the fiber material. , 22b is provided with an introduction device 24 for the absorbent particles. The fiber material introduction device 23 is provided with defibration means 231 for defibrating a raw material sheet 230 mainly composed of fibrous material and supplying the fibrous material into the duct 22 . As the core-forming material, only the fiber material may be used without using the absorbent particles.

The fiber stacking drum 21 includes a cylindrical drum main body 210 made of a rigid metal body, and an outer peripheral member 211 which is arranged over the outer peripheral portion of the drum main body 210 and forms an outer peripheral surface 21S of the fiber stacking drum 21. consists of The peripheral member 211 receives power from a prime mover such as a motor, and is driven to rotate in the direction of arrow R1 in FIG. and does not rotate. The interior of the drum body 210 is partitioned into a plurality of spaces A, B, and C in the circumferential direction. A decompression mechanism (not shown) is connected to the drum body 210 to decompress the interior thereof, and the spaces A to C can be maintained at a negative pressure by driving the decompression mechanism.

In the fiber stacking drum 21, the space A whose outer peripheral portion is covered with the duct 22 serves as a fiber stacking zone in which the core forming material can be stacked by suction from the inside. When the outer peripheral member 211 is rotated in the direction of the arrow R1 while the space A is maintained at a negative pressure, the stacking concave portion (not shown) formed in the outer peripheral member 211 passes over the space A. The negative pressure in the space A acts on the bottom of the stacking concave portion, and air is sucked through a large number of suction holes formed in the bottom. By suction through the suction holes, the core forming material conveyed in the duct 22 is guided to the accumulating recess and stacked on the bottom thereof to form the absorbent core 50 which is the stacked material. be done. On the other hand, the space B of the fiber stacking drum 21 is normally set to a weaker negative pressure than the space A or to zero pressure (atmospheric pressure). Since the area includes the area before and after it, the pressure is set to zero or a positive pressure. The accumulation recess has a shape corresponding to the shape to be given to the absorbent core 50 to be manufactured.

In this way, when the absorbent core 50 as a piled material is formed in the accumulation concave portion by suction, the absorbent core 50 is covered with the holding belt 25 so that the core-forming material falls off. The absorbent core 50 in the stacking recess is conveyed to the lower portion of the fiber stacking drum 21 by the rotation of the outer peripheral member 211, and after the holding by the holding belt 25 is released, the absorbent core 50 is discharged from the air ejection device 26. By ejecting air, the mold is released from the accumulating concave portion and transferred to the transfer portion 30 .

The transfer unit 30 includes a conveying means 31 capable of conveying an object to be conveyed on the conveying surface while sucking it. A suction box 33 as a suction means installed in the circular track of the conveyor belt 32 is included. The conveyor belt 32 forms a conveying surface for conveyed objects and has air permeability. The conveyor belt 32 is, for example, a mesh belt having many suction holes (not shown). The suction box 33 is installed at a position facing the air ejection device 26 with the conveyor belt 32 interposed therebetween so that the air blown out from the air ejection device 26 can be sucked. A core wrap sheet 51 is supplied in advance onto the conveyor belt 32 before the absorbent core 50 is transferred, and the absorbent core 50 released from the stacking recess is placed on the core wrap sheet 51. In this state, the sheet is conveyed to the folding section 40 located downstream of the transfer section 30 .

In the manufacturing method of this embodiment, as shown in FIGS. Adhesives 11A and 12A are applied by applying means 11 and 12 to the surface (inner surface) of the sheet 51 to which the absorbent core 50 is to be transferred. Specifically, the adhesive 11A is continuously applied by the application means 11 to the portion of the core wrap sheet 51 where the absorbent core 50 is not transferred, that is, the portion to be the extending portion 51E. , the adhesive 12A is continuously applied by the application means 12 to the portion where the absorbent core 50 is to be transferred (the central portion of the CD of the core wrap sheet 51). The coating means 12 is arranged downstream of the MD from the coating means 11, as shown in FIG. In the form shown in FIG. 3, the adhesive 11A is applied linearly or in a belt shape when viewed from above, and the adhesive 12A is applied spirally when viewed from above, but the application pattern of the adhesives 11A and 12A is not limited to this. , can be set arbitrarily. After the adhesives 11A and 12A are applied to substantially the entire inner surface of the core wrap sheet 51 in this manner, the absorbent core 50 is transferred to the central portion of the CD on the inner surface of the core wrap sheet 51 by the transfer unit 30, and further, The extending portion 51E of the core wrap sheet 51 is folded back to the upper surface side of the absorbent core 50 at the folding portion 40, so that the finally obtained absorbent body 1 has the absorbent core 50 as shown in FIG. and the core wrap sheet 51 are integrated through adhesives 11A and 12A. In the absorbent body 1 shown in FIG. 4, the overlapped extending portions 51E, 51E are joined to each other via the adhesive 11A in the overlapped portion 52, thereby unintentionally opening the overlapped portion 52. , the so-called opening phenomenon is prevented.

In the manufacturing method of this embodiment, as shown in FIG. It is placed on the core wrap sheet 51 so as to match the line 51CL. Therefore, in the core wrap sheet 51, the pair of extending portions 51E, 51E extending from the side edges 50S, 50S of the absorbent core 50 to the outside of the CD have an extension width (length along the CD) are the same. However, the extension widths of the pair of extension portions 51E, 51E may be different from each other.

As shown in FIG. 2, at a position downstream of the MD from the transfer position of the absorbent core 50 from the accumulating concave portion to the core wrap sheet 51 and upstream of the MD from the folding device 44 described later, A transport guide mechanism 34 for the absorbent core 50 is installed. The conveying guide mechanism 34 is arranged above the conveyor belt 32, and conveys the laminate of the core wrap sheet 51 and the absorbent core 50 while sandwiching it between the conveying guide mechanism 34 and the conveyor belt 32, thereby absorbing the core wrap sheet 51 and the absorbent core 50. It is used to keep the magnetic core 50 from deviating from the transport path.

5 to 7 show the folding section 40 provided in the manufacturing apparatus 10. FIG. The folding part 40 includes a conveying means 41 capable of conveying an object to be conveyed on the conveying surface while sucking it. The conveying means 41 of the folding section 40 includes an air-permeable conveyor belt 42 that moves in the direction of arrow R3 in FIG. consists of Conveyor belt 42 forms a conveying surface for conveyed articles, and conveyed articles, that is, a laminate of core wrap sheet 51 and absorbent core 50 is placed on the upper surface of conveyer belt 42 . The conveyor belt 42 itself is made of an impermeable material such as metal or resin, and as shown in FIG. This makes the conveyor belt 42 breathable. When the suction box 43 is operated, the object to be conveyed on the conveyor belt 42 (conveying surface) is sucked through the suction holes 42h.

The folding section 40 further includes a folding device 44 for the core wrap sheet 51 in addition to the conveying means 41 . The folding device 44 is installed on a part of the circular track of the conveyor belt 42 . The folding device 44 folds the extending portions 51E from the side edges 50S, 50S of the absorbent core 50 placed on the core wrap sheet 51 in the core wrap sheet 51 being conveyed toward the absorbent core 50 side. It has a mechanism for

The folding devices 44 are installed on both sides along the MD of the core wrap sheet 51 being conveyed. The folding device 44 is arranged on both sides of the CD with the conveyor belt 42 forming the conveying surface interposed therebetween. A pair of turn-back guides 441, 441 projecting inwardly of the CD from the upper end of the CD. An outer edge 441a of the folding guide 441 is connected to the upper end of the side wall portion 440, and an inner edge 441b of the folding guide 441 is a free edge that is not fixed to other members.

In this embodiment, the side wall portion 440 is composed of a flat plate-like member. As shown in FIG. 7, the side wall portion 440 is fixed to a support member 443 by an L-shaped member 442 at the lower end portion of the side wall portion 440 (the end portion opposite to the connecting portion with the folding guide 441). , are arranged so as to stand up in the vertical direction (vertical direction in FIG. 7). The support member 443 is, for example, a plate-like member, and is installed with its plate surface aligned with the horizontal direction (horizontal direction in FIG. 7).

In this embodiment, the folding guide 441 is composed of a flat plate-like member including a triangular portion in plan view as shown in FIG. are arranged substantially parallel to each other. The pair of turn-back guides 441 , 441 are arranged substantially parallel to the conveyor belt 42 forming the conveying surface, and are arranged to face the conveyor belt 42 . The outer edge 441a of the folding guide 441 is linear parallel to the MD, while the inner edge 441b of the folding guide 441 is linear extending obliquely along the MD from the outside to the inside of the CD. be. Therefore, the fold-back guide 43b has a projecting width W toward the inside of the MD that gradually increases along the MD. In addition, portions of the pair of turn-back guides 441, 441 located on the downstream side of the MD overlap with each other with a gap therebetween to form an overlapping portion 441c. The gap between the pair of folding guides 441, 441 in the overlapping portion 441c is normally about 1 to 30 mm.

By the way, since the absorbent core 50 has a narrowest portion 50N (constricted portion N) and the length of the CD, that is, the width varies along the MD, the fold-back guide 441 is used to fold the core wrap sheet 51 according to a conventional method. When the extending portion 51E is folded back so as to cover the upper surface of the absorbent core 50 (the surface opposite to the surface facing the conveyor belt 42), as described above, as shown in FIG. There is concern that wrinkles may occur in the core wrap sheet 51 at the position of the narrow portion 50N (constricted portion N), or an uncovered portion (opening) may occur in the absorbent body 1 . In particular, in the region where the overlapped portion 441c of the pair of folded guides 441, 441 exists, as described above, the core forming material is caused to flow by the air flow (not shown) flowing from the outside through a small gap present in the overlapped portion 441c. It is feared that inconveniences such as falling off of the absorbent core 50 and loss of shape of the absorbent core 50 may be caused.

However, in the manufacturing method of the absorbent body 1, in the area where the folding guide 441 is arranged, it acts on the object to be conveyed (the laminate of the core wrap sheet 51 and the absorbent core 50) via the conveying surface (conveyor belt 42). By making the suction force different inside and outside the narrowest portion 50N of the absorptive core 50 and the imaginary extension area when the narrowest portion 50N is virtually extended in the MD, the above concern is eliminated. are doing.

That is, in the manufacturing method of the absorbent body 1, as shown in FIG. 6, a pair of imaginary straight lines VL extending to MD through both ends of CD of the narrowest width portion 50N of the absorbent core 50 on the conveying surface (conveyor belt 42) , VL as a boundary, the conveying surface moving in the "arrangement area of the folding guide 441" is positioned on both sides of the central area 45 sandwiched between the pair of imaginary straight lines VL and VL, and on both sides of the central area 45. The suction force 46 V of the side regions 46 is made lower than the suction force 45 V of the central region 45 . That is, the conveying surface (conveyor belt 42) passing through the arrangement area of the turn-back guide 441 is divided into three CD areas, and the central area 45 located in the center of the CD among the three areas is relatively sucked. A high suction portion with a large force is used, and two lateral regions 46 positioned on both sides of the CD are used as low suction portions with a relatively small suction force.

The above-mentioned "arrangement area of the folding guide" is an area where the folding guide 441 is arranged so as to overlap the transport surface (conveyor belt 42 in FIG. 6) in plan view as shown in FIG. . It should be noted that, as shown in FIG. 6, it is not necessary to arrange the folding guides 441 on both sides of the CD of the conveying surface (conveyor belt 42) in order to be the "arrangement area of the folding guide". Even if the folding guide 441 is arranged only on one side of the , the area where the folding guide 441 is arranged only on that one side is the "placement area of the folding guide".

The central region 45 is a portion that overlaps in plan view with the "narrowest portion 50N and a virtual extension area when the narrowest portion 50N is virtually extended in MD" on the conveying surface (conveyor belt 42). , as shown in FIG. 6, overlaps the absorbent core 50 over the entire MD of the absorbent core 50 during transport. On the other hand, since the side region 46 includes a portion located outside the CD of the narrowest portion 50N on the conveying surface (conveyor belt 42), the suction holes 42h in this portion do not overlap the absorbent core 50. , the suction force 46V (see FIG. 7) acting through the suction hole 42h tends to act on the extending portion 51E of the core wrap sheet 51 as it is. This causes inconveniences such as Therefore, in the manufacturing method of the absorbent body 1, in the arrangement region of the folding guide 441 where the folding operation of the core wrap sheet 51 is performed, a magnitude relationship of "suction force 46V in the side area 46<suction force 45V in the central area 45" is established. By establishing and intentionally reducing the suction force of 45 V, the above concern is eliminated, the core wrap sheet 51 does not wrinkle, and the material forming the absorbent core 50 does not fall off or lose its shape. , the absorbent body 1 in which the absorbent core 50 is reliably covered with the core wrap sheet 51 can be manufactured.

In the present specification, the “suction force” is a value defined by “suction static pressure (Pa)×suction area (m ² )÷length of CD of suction region (m)” N/m is a physical quantity with the dimension of For example, the suction force 46V of the side region 46 is expressed as "suction static pressure (Pa) of the side region 46 × area (m ² ) of the side region 46 ÷ CD length of the side region 46 (m)" Defined.

The magnitude relationship of "attractive force 46V in side areas 46<attractive force 45V in central area 45" does not need to be established for the entire central area 45 (the area sandwiched between a pair of imaginary straight lines VL, VL). , at least about the central portion of the CD of the central region 45 . That is, in the present invention, it is sufficient that the magnitude relationship of "attraction force 46 V in the side regions 46<attraction force 45 V at the central portion of the CD in the central area 45" is satisfied. In other words, the attraction force 45V of "the portion of the central area 45 near the side area 46" need not be greater than the attraction force 46V of the side area 46. FIG.

For example, the attraction force 45V in the portion of the central area 45 closer to the side area 46 may be made equal to the attraction force 46V in the side area 46 . In other words, there is a magnitude relationship of "attractive force 46V in the side area 46 and attractive force 45V at the portion near the side area 46 in the central area 45<attractive force 45V at the central portion of the CD in the central area 45". good too. Due to the establishment of such a size relationship, if the absorbent core 50 meanders in the arrangement area of the folding guide 441, the position of the absorbent core 50 is deviated from the original proper position, and the position of the absorbent core 50 is shifted. A material for forming an absorbent core 50 that does not wrinkle the core wrap sheet 51 even when a part of the narrowest portion 50N protrudes from the central region 45 of the conveying surface (conveyor belt 42) to the side region 46. It is possible to cover the absorbent core 50 with the core wrap sheet 51 without falling off or losing its shape.

In this way, from the viewpoint of ensuring that the predetermined effects of the present invention are exhibited even if the absorbent core 50 is misaligned, the above-mentioned "portion near the side area 46 in the central area 45", that is, the central A portion of the area 45 having an attraction force equivalent to the attraction force 46V of the side area 46 is preferably within 3 mm inward of the CD (on the side of the central area 45) from the boundary between the central area 45 and the side area 46, More preferably, the area is within 10 mm.

The ratio (46V/45V) of the attractive force 46V of the side regions 46 to the attractive force 45V of the central region 45 is preferably 0.5 or less, more preferably 0.1 or less, and most preferably 45V>46V. preferably zero. If the attraction force 46V in the side areas 46 is zero, the ratio is zero. If the suction force 46V is zero, the suction force is zero at the portion of the conveying surface (conveyor belt 42) located outside the CD of the narrowest portion 50N in the area where the folding guide 441 is arranged. Problems such as wrinkling of the core wrap sheet due to the suction force are more effectively prevented.

The suction force 45V of the central region 45 is preferably 500 N/m or more, more preferably 1000 N/m or more, and preferably 3000 N/m or less, more preferably 2000 N/m or less.
When the suction force 46V of the side area 46 is not zero, the suction force 46V is preferably 100 N/m or more, more preferably 250 N/m or more, and preferably 1000 N/m or less, more preferably 500 N/m or less. is.

The suction force on the conveying surface can be adjusted by appropriately adjusting the air permeability of the conveyor belt 42 forming the conveying surface, the suction force of the suction box 43 which is a suction means for performing a suction operation, and the like.

For example, by making the opening areas of the suction holes 42h of the conveyor belt 42 forming the conveying surface different between the side regions 46 and the central region 45, the above-mentioned magnitude relation "the suction force 46V of the side regions 46 < the center It is possible to establish an attractive force of 45V in the region 45. Specifically, for example, the opening area of the suction holes 42h located in the side region 46 (the maximum opening area if there are a plurality of suction holes 42h with different opening areas in the side region 46) is It may be smaller than the opening area of the suction holes 42h located in the area 45 (the minimum opening area when there are a plurality of suction holes 42h with different opening areas in the central area 45). When the opening area of the suction holes 42h located in the side regions 46 is zero, that is, when the suction holes 42h are not formed in the side regions 46, the suction force 46V of the side regions 46 is zero. The ratio (46P/45P) of the opening area 46P of the suction holes 42h located in the side areas 46 to the opening area 45P of the suction holes 42h located in the central area 45 is preferably 0 on the premise that 45P>46P. 0.5 or less, more preferably 0.1 or less, and most preferably zero.

Further, for example, by making the suction force of the suction box 43, which is the suction means in the region where the folding guide 441 is arranged, different between the side region 46 and the central region 45, the above-mentioned magnitude relationship "the suction force 46 V of the side region 46 <Attraction force of 45V in central region 45” can be established. Specifically, for example, the suction box 43 has a portion that performs suction in the central region 45 (hereinafter also referred to as a “central region suction portion”) and a portion that performs suction in the side regions 46 (hereinafter referred to as a “side region Also referred to as "suction portion"), each of the suction portions can perform a suction operation independently, and the suction force by the side area suction portion is less than the suction force by the central area suction portion. should also be made smaller. In this case, if the suction force by the side area suction portion is zero, ie, non-suction, the suction force 46V of the side area 46 becomes zero. Also, a partitioning member (not shown) that divides the suction box 43 into the central area suction portion and the side area suction portion may be movable (for example, movable to the CD). By using the configured suction box 43, it becomes possible to support absorbent cores 50 of various shapes.

The absorbent body, which is the production object of the production method of the present invention, is suitable for absorbent articles. The term "absorbent article" as used herein broadly includes articles used for absorbing bodily fluids (urine, loose stool, menstrual blood, sweat, etc.) excreted from the human body. These include pants-type disposable diapers, sanitary napkins, sanitary shorts, incontinence pads, and the like. In the absorbent article, the absorbent body is arranged so that its longitudinal direction (that is, MD at the time of manufacture) matches the front-rear direction of the wearer.

Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the scope of the present invention. The absorbent core to which the present invention is applied has only to have a narrowest portion in which the length of the direction perpendicular to transport (CD) varies along the direction of transport (MD). 1 and FIG. 3, and may have two or more narrowest portions, for example. The following notes are further disclosed with respect to the above-described embodiments of the present invention.

<1> A core wrap sheet having an absorbent core laminated thereon is placed as the object to be conveyed on the conveying surface of a conveying means capable of conveying the object on the conveying surface while sucking it, and suction is performed. While the conveying surface is moved in one direction, the conveyed object is conveyed, and during the conveying, the core wrap sheet is conveyed perpendicular to the conveying direction from both side edges along the conveying direction of the absorbent core. a covering step of folding back the extending portion extending outward in the orthogonal direction to cover the upper surface of the absorbent core using a folding guide arranged along the conveying direction above the conveying surface; A method for manufacturing an absorbent body, comprising:
The absorbent core has different lengths in the direction perpendicular to transport along the direction of transport, and has a narrowest portion where the length in the direction perpendicular to transport is the smallest,
With a pair of imaginary straight lines extending in the conveying direction through both ends of the narrowest portion in the conveying orthogonal direction as boundaries, the conveying surface moving in the area where the folding guide is arranged is sandwiched between the pair of imaginary straight lines. The absorber is divided into a central region and side regions positioned on both sides of the central region in the direction perpendicular to the conveying direction, and the suction force of the side regions is made lower than the suction force of the central region. manufacturing method.
<2> The method for manufacturing the absorbent body according to <1>, wherein the suction force of the portion of the central region closer to the side region is equal to the suction force of the side region.
<3> The portion of the central region closer to the side region is preferably within 3 mm, more preferably within 10 mm, inward in the direction orthogonal to the transport from the boundary between the central region and the side region. , the method for producing an absorbent body according to <2>.

<4> The ratio of the attraction force of the side regions to the attraction force of the central region (the latter/former) is preferably 0.5 or less, more preferably 0.1 or less, above <1> to <3 A manufacturing method of the absorber given in any 1 of >.
<5> The attraction force of the central region is preferably 500 N/m or more, more preferably 1000 N/m or more, and preferably 3000 N/m or less, more preferably 2000 N/m or less, <1> to The method for manufacturing an absorbent body according to any one of <4>.
<6> The suction force of the side area is preferably 100 N/m or more, more preferably 250 N/m or more, and preferably 1000 N/m or less, more preferably 500 N/m or less, the <1> The method for producing an absorbent body according to any one of <5>.

<7> The conveying means includes an air-permeable conveyor belt having a plurality of suction holes and moving on a predetermined circular track, and suction means installed in the circular track, and the conveying surface is formed by the conveyor belt, and
The absorbent body according to any one of <1> to <6>, wherein when the suction means is operated, the object to be transferred on the transfer surface is sucked through the suction holes. Production method.
<8> The suction force in the side regions is made lower than the suction force in the central region by varying the opening area of the suction holes in the side regions and the central region, <7> 3. The method for manufacturing the absorber according to 1.
<9> The ratio of the opening area of the suction holes located in the side regions to the opening area of the suction holes located in the central region (the latter/the former) is preferably 0.5 or less, more preferably is 0.1 or less, more preferably zero.
<10> By making the suction force of the suction means different between the side regions and the central region, the suction force of the side regions is made lower than the suction force of the central region, the <7> to <9> The method for manufacturing an absorbent body according to any one of <9>.
<11> The suction means is divided into a central area suction section that performs suction in the central area and a side area suction section that performs suction in the side areas, and both of these suction sections perform suction operations independently. made possible,
The method for manufacturing an absorbent body according to any one of <7> to <10>, wherein the suction force by the side area suction parts is made smaller than the suction force by the central area suction parts.
<12> The method for manufacturing an absorbent body according to <11>, wherein a dividing member that divides the suction means into the central region suction portion and the side region suction portion is movable.
<13>
The method for manufacturing an absorbent body according to any one of <1> to <5> and <7> to <12>, wherein the suction force of the side areas is zero.

1 Absorber 10 Absorber Manufacturing Apparatus 20 Fiber Stacking Section 21 Fiber Stacking Drum 22 Duct 30 Transfer Section 31 Conveying Means of Transfer Section 32 Conveyor Belt 33 Suction Box (Suction Means)
40 Folding part 41 Conveying means 42 of the folding part Conveyor belt 42 h Conveyor belt suction hole 43 Suction box (suction means)
44 Folding device 440 Side wall portion 441 Folding guide 441c Folding guide overlapping portion 45 Central area 46 of the conveying surface Side area 50 of the conveying surface Absorbent core 50S Side edge 50N along the conveying direction (longitudinal direction) of the absorbent core Absorbency Narrowest part of core 51 Core wrap sheet 51E Extension part 52 of core wrap sheet Overlapping part N of core wrap sheet Narrow part

Claims (5)

A core wrap sheet having an absorbent core laminated thereon is placed as the object to be conveyed on the conveying surface of a conveying means capable of conveying the object to be conveyed while sucking the object on the conveying surface, and conveying the object while performing suction. The transported object is transported by moving the surface in one direction, and during transport, the core wrap sheet is stretched from both side edges along the transport direction of the absorbent core in the transport orthogonal direction perpendicular to the transport direction. a covering step in which the outwardly extending portion is folded back so as to cover the upper surface of the absorbent core using a folding guide arranged along the conveying direction above the conveying surface. A method of manufacturing a body, comprising:
The absorbent core has different lengths in the direction perpendicular to transport along the direction of transport, and has a narrowest portion where the length in the direction perpendicular to transport is the smallest,
With a pair of imaginary straight lines extending in the conveying direction through both ends of the narrowest portion in the conveying orthogonal direction as boundaries, the conveying surface moving in the area where the folding guide is arranged is sandwiched between the pair of imaginary straight lines. The absorber is divided into a central region and side regions positioned on both sides of the central region in the direction perpendicular to the conveying direction, and the suction force of the side regions is made lower than the suction force of the central region. manufacturing method. The conveying means includes an air-permeable conveyor belt having a plurality of suction holes and moving on a predetermined revolving track, and suction means installed in the revolving track. made up of belts,
2. The method of manufacturing an absorbent body according to claim 1, wherein when said suction means is operated, the object to be conveyed on said conveying surface is sucked through said suction holes. 3. The absorption according to claim 2, wherein the side areas and the central area have different opening areas of the suction holes so that the suction force in the side areas is lower than the suction force in the central area. body manufacturing method. 4. The method according to claim 2 or 3, wherein the suction force of the suction means is different between the side areas and the central area so that the suction force of the side areas is lower than that of the central area. A method for manufacturing an absorbent body. The method for manufacturing an absorbent body according to any one of claims 1 to 4, wherein the side areas have a suction force of zero.

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