WO2014207698A1

WO2014207698A1 - Method and apparatus for manufacturing absorbent sanitary articles

Info

Publication number: WO2014207698A1
Application number: PCT/IB2014/062629
Authority: WO
Inventors: Matteo Piantoni; Valerio Soli
Original assignee: Gdm S.P.A.
Priority date: 2013-06-28
Filing date: 2014-06-26
Publication date: 2014-12-31
Also published as: ITBO20130335A1

Abstract

In a method and an apparatus (10) for manufacturing absorbent sanitary article (1), a first web (20) intended to define the top sheet (5) of the absorbent sanitary articles (1) is fed along a first path (P1) along which strips or side wings (3) are connected in succession and removably, by means of first end portions (35) thereof, to respective and opposite end portions of the first web (20) in such a way as to make them project outwards from the first web (20); the strips (3) are then folded by 180° about their respective median lines, in such a way that their second end portions (37) adhere to the top surface (21b) of the first web (20); a third web (39) is associated with the first web (20) with absorbent pads (7) and the second end portions (37) of the strips being interposed between them; the first web (20) and the third web (39) are then connected to each other.

Description

DESCRIPTION

METHOD AND APPARATUS FOR MANUFACTURING ABSORBENT

SANITARY ARTICLES

Technical field

This invention relates to a method and an apparatus for manufacturing absorbent sanitary articles such as, for example, baby nappies, incontinence nappies and the like.

More specifically, this invention relates to a method and an apparatus for attaching to the webs of material used to make the absorbent sanitary articles strips or side wings constituting the fastening elements by which the absorbent sanitary articles are held in place on the wearer's body. In the description which follows, reference is made to disposable nappies by way of example and for convenience of description without limiting the scope of the invention.

Background art

As is known, disposable nappies comprise an absorbent pad, normally made from cellulose fibre, enclosed within a soft cover. The cover is defined by a permeable inner layer or sheet of non-woven fabric and an impermeable outer layer or sheet of polyethylene, joined to each other and provided with shaped border portions and sealing elastic bands.

Usually, the nappies have a front part and a rear part where the above mentioned fastening elements are located.

The fastening elements usually consist of strips of plastic sheet, for example of elastomeric material, having at least one adhesive surface or provided with fastening means of some other kind to be attached to the front part of the nappies. Each nappy is provided with a pair of fastening elements, located on each side of the nappy to allow it to be wrapped and fastened round the wearer's waist.

Very often, the fastening elements are distributed in pairs on the web from which the above mentioned impermeable outer sheets of polyethylene are obtained and which is fed continuously along a feed line.

The fastening elements or side wings are usually obtained from a continuous web of elastic material which is fed through a first cutting station which cuts it lengthways to obtain two continuous parallel bands. Next, the two bands are fed to a second cutting station which cuts each band into individual strips to obtain a succession of pairs of fastening elements.

The pairs of side wings are then fed to the feed line of the aforementioned web and are sealed at one end to the web in a transversal position in such a way that the other end is free, projects laterally outwards from the web and can then be folded onto the web itself.

The machines which use this method of making the absorbent articles have one major disadvantage, which arises in particular when the absorbent articles are considerably large in size because they are intended for adult users.

Indeed, particularly in such a case, the fastening elements are relatively long and it is very difficult to prevent them from adopting incorrect positions before and while they are folded against the web. The higher the feed speed of the web is, the higher the likelihood that this will occur because the fastening elements projecting in flag-like fashion from the side of the web tend to flap about on account of air resistance as they move forward.

Patent US6936129B2 suggests folding the fastening elements several times on themselves before connecting them to the web from which the above mentioned impermeable outer sheets of polyethylene are obtained. Connection is accomplished by joining to the web the ends of the fastening elements opposite to those having an adhesive surface or provided with fastening means of some other kind, and the fastening elements are further folded so they can be positioned against the web. A method of this kind is not free of disadvantages, however, because controlling the fastening elements after they have been folded on themselves several times is anything but easy and parts of the fastening elements are often positioned incorrectly. Moreover, the fact of joining to the web the ends of the fastening elements opposite to those having an adhesive surface or provided with fastening means of some other kind means that the free ends of the fastening elements are weighed down by the fastening means themselves and, in machines operating at high speed for the manufacture of absorbent articles, have a strong tendency to move out of position on account of inertia and air resistance.

In patent EP1437993B1 the two fastening elements are applied simultaneously to one face of the web (top sheet), which will define the breathable inner surface of the absorbent articles, with the respective ends perfectly juxtaposed with each other since they have been obtained from the same strip of web material cut in half transversely. Next, the border portions of the web (top sheet), together with the outer ends of the two fastening elements, are folded under the web and another web (back sheet), which will define the impermeable outer surface of the absorbent articles is juxtaposed with the first web (top sheet) and sealed thereto at suitable zones. In an apparatus made according to what is described in patent EP1437993B1 it is impossible to control relatively long fastening elements intended to constitute, in their entirety, a sort of waistband, because the fact that the respective ends of the two fastening elements touch each other upon placement in contact with the web (top sheet) greatly limits the length which is compatible with the operation of the apparatus itself.

Patent US7820003B2 describes another method of making absorbent articles of the kind described above. According to this operating method, pairs of fastening elements, already folded substantially in half and extending towards each other in the context of each pair, are superposed and connected to respective lateral border zones of a web. Each of the fastening elements has an edge which protrudes laterally from the web and these protruding edges are folded against the other face of the web itself after the pairs of fastening elements have been applied to the web. An apparatus operating this way is relatively complex because it requires suitable devices upstream of the web feed line in order to fold the fastening elements in half before they are applied to the web. Moreover, manipulating and transporting these folded fastening elements before they are applied to the web are tricky operations because it is not easy to keep the fastening elements in the right position while they are being transferred.

Aim of the invention

This invention has for an aim to provide a method and an apparatus for manufacturing absorbent articles and which is free of the disadvantages inherent in the above mentioned apparatuses and methods.

The invention accordingly provides a method and an apparatus for manufacturing absorbent articles as set out in the appended claims.

Brief description of the drawings

The invention will now be described with reference to the accompanying drawings which illustrate a non-limiting embodiment of it and in which:

- Figure 1 illustrates an absorbent article which can be made using the apparatus of this invention;

- Figure 2 shows a schematic transverse view, in cross section, of the absorbent article of Figure 1 ;

- Figure 3 shows a schematic perspective view of the apparatus of the invention; and

- Figure 4 shows a schematic perspective view of a portion of the apparatus of Figure 3. Detailed description of preferred embodiments of the invention

With reference to Figures 1 and 2, the numeral 1 denotes a disposable absorbent article consisting of a pants nappy, comprising a central absorbent body 2 and a pair of side strips or wings 3 extending from the sides of the central absorbent body 2.

The side wings 3 are made, for example, from non-woven fabric, preferably elastic.

In pants nappies, the central absorbent body 2 is substantially rectangular in shape and comprises an outer layer 4 (the bottom one in Figure 1 ) made of an impermeable material, and an inner layer 5 (the top one in Figure 1 ) made of a permeable material.

The outer layer 4 is made, for example, of plastic, preferably polyethylene, and is known as "back sheet", while the inner layer 5 is made, for example, of non-woven fabric, and is known as "top sheet".

The central absorbent body 2 also comprises an absorbent pad 7 enclosed between the back sheet 4 and the top sheet 5 (Figures 1 and 2). The absorbent pad 7 may consist, for example, of a loose mass of fibres, known as fluff.

The central absorbent body 2, in use, is folded at least partly on itself in such a way as to define two facing portions. More specifically, with reference to a nappy 1 worn by a user, a front portion 8a and a rear portion 8b are thus defined.

The pair of side wings 3 joins the front portion 8a to the rear portion 8b of the central absorbent body 2 on opposite sides of the central absorbent body 2 itself.

The side wings 3 are located substantially at opposite ends of the central absorbent body 2 and at respective side border portions 9a, 9b of the central absorbent body 2 itself.

Prior to use, the pants nappies 1 are usually folded onto themselves, with the side wings 3 tucked between the facing front portion 8a and rear portion 8b.

As shown in particular in Figure 3, the nappies 1 are made using an apparatus denoted in its entirety by the numeral 10.

The apparatus 10 comprises a line 1 1 for feeding along a predetermined direction L a continuous ribbon 12 of semi-finished absorbent sanitary articles 1 attached to each other in succession and intended to be separated from the selfsame ribbon 12 one after the other,

It should be noted that the term "semi-finished absorbent sanitary articles" is used to mean a continuous ribbon 12 consisting, in the embodiment illustrated, and as will become clearer as this description continues, of a bottom web provided with a plurality of absorbent pads 7 equally spaced thereon, and a top web associated with the bottom web to form a finished continuous web from which single finished absorbent articles of predetermined size are severed transversely to its line of feed at predetermined intervals.

The line of feed 1 1 extends horizontally along feeding means comprising an endless horizontal conveyor belt 13 looped around end rollers 14 (only one of which is shown in Figure 3), as far as a cutting station 15, where a cutting device 16 divides the continuous ribbon 12 into individual absorbent sanitary articles 1 not shown in Figure 3.

The absorbent sanitary articles 1 are then fed to further processing stations, not illustrated, by an endless horizontal conveyor belt 17, partly illustrated, looped around end rollers 18 (only one of which is shown in Figure 3).

The conveyor belt 13 runs under a roller 19, substantially tangent thereto and rotatable about a horizontal axis parallel to the axes of the rollers 14. The roller 19 defines a transmission means for the web 20 which will constitute the above mentioned inner layer or top sheet 5 of the absorbent sanitary articles 1 .

The web 20 has two opposite surfaces 21 a and 21 b which will eventually be on the outside and on the inside of the absorbent sanitary articles 1 , respectively.

The web 20 is unwound continuously from a roll (not illustrated, located on the right of the apparatus 10, looking at Figure 3), is directed towards the top surface of the roller 19 following a straight horizontal path P1 towards the left of the apparatus 10, again looking at Figure 3, is wound round the roller 19 for an arc of 180°, reverses its feeding direction and leaves the roller 19 following a straight horizontal path P2.

The path P2 runs underneath the path P1 parallel thereto, and is followed by the web 20 along a direction of travel opposite to the direction it follows along the path P1 , that is to say, it is directed towards the right of the apparatus 10, looking at Figure 3.

Along the path followed by the web 20, upstream of the roller 19, there is an assembling device comprising a unit 22 for applying pairs of juxtaposed side wings 3 to the web 20 itself.

The unit 22 comprises a plurality of rotary conveyors (five in the example illustrated) comprising rollers with horizontal axes parallel to the axis of rotation of the roller 19. The unit 22 is described in detail in patent EP2294000B1 which is incorporated herein by reference for completeness of description.

Substantially at its bottom end, the unit 22 comprises a cutting device 23 for sequentially severing a continuous web 24 made, for example, of elastomeric material unwound from a roll not illustrated, to obtain individual strips which, once incorporated in the absorbent sanitary articles 1 , constitute the aforementioned side wings 3.

The cutting device 23 comprises a bladed roller 24' rotating anticlockwise and, for severing purposes, acting in conjunction with the cylindrical peripheral surface of a conveying roller 25 which has a cylindrical surface provided with holes connected to a source of suction for holding down the strips 3 after they have been severed from the web 24 and which rotates clockwise about an axis parallel to the axis of the roller 24'.

Substantially tangent to the roller 25, upstream to downstream with reference to its direction of rotation, are two rollers 26 and 27, both rotating anticlockwise and constituting a separating device 28 for forming respective successions of side wings 3.

The rollers 27 and 28 are in turn both substantially tangent to a single roller 29 rotating clockwise and constituting a device 30 for forming pairs of strips 3.

Lastly, the numeral 31 denotes a roller, rotating clockwise, substantially tangent both to the roller 26 and to the roller 29, and constituting an accelerating device 32.

As it passes between the roller 24' of the cutting device 23 and the roller 25, the web 24 is divided into alternate strips 3 (as described in detail in the aforementioned patent EP2294000B1 ), held down by suction on the cylindrical surface of the selfsame roller 25 and oriented in opposite directions relative to each other.

The roller 26 and the roller 27, tangent to the roller 25 at two transfer positions, labelled 33 and 34, are substantially the same, rotate anticlockwise and have on their respective cylindrical surfaces a plurality of seats (not illustrated) spaced at equal angular intervals according to a predetermined spacing.

Each of the seats receives and holds down by suction one strip 3, and is defined by a shoe (not illustrated) slidable in a direction parallel to the axes of the rollers 26 and 27, under the action of actuating means not illustrated, between two limit positions.

Starting from the respective transfer positions 33 and 34, the shoes slide in opposite directions as the rollers 26 and 27 rotate, so as to form respective successions composed of strips 3 oriented in the same direction and spaced from each other, parallel to the axes of the rollers, by a stretch of predetermined length.

The roller 29, which rotates clockwise, has on its cylindrical outside surface, in the proximity of each of its two longitudinal ends, a ring of seats not illustrated, and is capable of receiving one after the other the strips 3 forming part of each of the aforementioned successions and transferring pairs of juxtaposed strips 3 to a corresponding pair of seats (not illustrated) of the roller 31 . The pairs of seats of the roller 31 are movable relative to the roller 31 itself, as described in detail in patent application EP2162106A2, so as to increase the mutual distance between successive pairs of strips 3, thereby spacing them by a stretch coinciding with the spacing of the stretches of the ribbon 12 which will constitute the individual absorbent sanitary articles 1 .

At a position of tangency between the roller 31 and a stretch of the web 20 in transit along the top straight horizontal path P1 , the pairs of side wings 3 to be associated with a respective absorbent sanitary article 1 are removably connected in succession to the web 20 itself by means of a small seal or removable glue. More precisely, when each pair of side wings 3 carried by the roller 31 comes near the web 20, an end portion 35 of a side wing 3 is connected to the web 20 in the proximity of each side border portion thereof, placing the end portion 35 in contact with the surface of the web 20 located at the bottom in Figure 3 and which will constitute the surface of the top sheet on the outside of the ribbon 12, that is to say, on the outside of the absorbent sanitary articles 1 obtainable from the ribbon 12. This end portion 35 of the side wings 3 is the portion that will be manipulated by the user of the absorbent sanitary articles 1 , and may be provided in essentially known manner with fastening means, not illustrated, consisting for example of a film of replaceable adhesive, possibly covered by a small piece of silicone sheet material, or consisting of a piece of Velcro, to enable the user, when the absorbent sanitary article 1 is put on, to fasten this end portion to the end portion 35 of the other side wing 3 constituting the pair.

Immediately after connection, the side wings 3 attached to the web 20, which are extended and project outwards from the longitudinal edges of the web 20 itself, are engaged by a folding device 36, which folds them by 180°, turning them upwards in Figure 3, about respective lines parallel to the direction of the path P1 and substantially half way along each side wing 3.

This folding step positions the end portions 37 opposite the end portions 35 in contact with the surface of the web 20 located at the top in Figure 3 and which will constitute the surface of the top sheet on the inside of the ribbon 12, that is to say, on the inside of the absorbent sanitary articles 1 obtainable from the ribbon 12.

The folding device 36, as shown schematically in Figure 4, comprises two pairs of mutually adjacent conveyor belts 38 which are positioned respectively in the proximity of each of the flanks of the stretch of web 20 in transit along the top straight horizontal path P1 and which extend along a substantially helical path to receive and guide between them the side wings 37 just connected to the web 20 and in such a way as to fold them by 180° as mentioned above.

After this folding step, the side wings 3 of each pair are folded substantially in half and do not risk adopting incorrect positions as often happens, especially in the case of relatively very long side wings, in similar apparatuses known in the prior art.

The web 20 is then wound round the roller 19 along an arc of 180° and moves away therefrom following the straight horizontal path P2 underneath the path P1 and directed towards the right in Figure 3.

On leaving the roller 19 the web 20 is superposed over an incoming web 39 which will constitute the outer layer or back sheet 4 of the absorbent sanitary articles 1 and which is in the meantime moving along the feed line L on the horizontal conveyor belt 13.

It should be noted, therefore, that the roller 19, besides constituting a transmission means for the web 20, also constitutes a means of feeding and coupling the web 20 and the web 39 to each other.

Positioned on the top surface of the web 39 there are absorbent pads 7 spaced at predetermined intervals according to a spacing which coincides with the spacing of the stretches of the ribbon 12 which will constitute the individual absorbent sanitary articles 1 .

From this it may be inferred that the ribbon 12 coincides with the web 39. The absorbent pads 7 are associated with the top surface of the web 39 before coupling to the web 20.

Upon coming into contact with each other as described above, the webs 20 and 39 progressively enclose between them the absorbent pads 7, which are placed at the exact positions relative to the side wings 3 of the absorbent sanitary articles 1 which they respectively form part of after the ribbon 12 is severed.

As soon as they come into contact with each other, the side border portions of the two webs 20 and 39 are joined by sealing or gluing by means of a sealing device of known type, not illustrated, and the ends 37 of the side wings 3 are thus enclosed between, and joined to, the webs 20 and 39 themselves.

The cutting device 15, as described above, then severs the ribbon 12 to separate one after the other the absorbent sanitary articles 1 where the side wings 3 are folded in the manner described, and the absorbent sanitary articles 1 are then passed on by the conveyor belt 17 to further processing stations not illustrated.

Claims

1 . A method for manufacturing absorbent sanitary articles by making a continuous ribbon (12) of semi-finished absorbent sanitary articles (1 ) attached to each other in pairs and intended to be separated from the ribbon (12) one after the other, comprising the steps of feeding along a first path (P1 ) a first web (20) intended to define the top sheet (5) of the absorbent sanitary articles (1 ), the first web (20) having two surfaces, an outside one (21 a) and an inside one (21 b), opposite to each other and defining the outside and the inside of the absorbent sanitary articles (1 ), respectively; separating in succession from a second web (24) strips (3) constituting side wings or fastening elements intended to be associated in pairs with respective opposite flanks of the absorbent sanitary articles (1 ); associating the first web (20) with a third continuous web (39) intended to define the back sheet (4) of the absorbent sanitary articles (1 ), while the selfsame first web (20) moves along a second path (P2), with absorbent pads (7) being interposed between the first web (20) and the third web (39) according to a spacing coinciding with the spacing of the stretches of the ribbon (12) that will constitute the individual absorbent sanitary articles (1 );

connecting the first web (20) and the third web (39) to each other at respective predetermined zones; separating in succession from the ribbon (12) the absorbent sanitary articles (1 ) provided with the folded strips (3); characterized in that it comprises a first step of connecting respective first end portions (35) of the strips (3) in succession and removably to two border portions of the first web (20), in the same plane and on the outside surface (21 a); the strips (3) projecting outwards from the first continuous web (20) according to directions substantially perpendicular to the first web (20) itself; a second step, following the first step, of folding each strip (3) by 180° about its substantially median line, in such a way that its second end portion (37) opposite to the first end portion (35) adheres to the inside surface (21 b); during the step of associating the first web (20) with the third continuous web (39) intended to define the back sheet (4), the second end portions (37) of the strips being enclosed between the first web (20) and the third web (39).

2. The method according to claim 1 , characterized in that the first path (P1 ) and the second path (P2) are parallel to each other and the first web (20) travels along the paths (P1 , P2) in opposite directions; the first web (20) being driven around transmission means (19) which reverse its direction of feed as it passes from the first path (P1 ) to the second path (P2).

3. The method according to claim 1 or 2, characterized in that the absorbent pads (7) are associated with the third web (39) before the latter is coupled to the first web (20).

4. An apparatus for manufacturing absorbent sanitary articles by making a continuous ribbon (12) of semi-finished absorbent sanitary articles (1 ) attached to each other in pairs and intended to be separated from the ribbon (12) one after the other, comprising first feed means for feeding along a path (P1 ) the first web (20) intended to define the top sheet (5) of the absorbent sanitary articles (1 ), the first web (20) having two opposite surfaces (21 a, 21 b) intended to be situated on the outside and on the inside of the absorbent sanitary articles (1 ), respectively; first cutting means (23) for separating in succession from a second continuous web (24) strips (3) constituting side wings or fastening elements which must be associated in pairs with respective opposite flanks of the absorbent sanitary articles (1 );

second feed means (13) for feeding a third continuous web (39) intended to define the back sheet (4) of the absorbent sanitary articles (1 ), for associating the selfsame first web (39) with the first web (20) while the first web (20) moves along a second path (P2) and absorbent pads (7) are interposed between the first web (20) and the third web (39) according to a spacing coinciding with the spacing of the stretches of the ribbon (12) that will constitute the individual absorbent sanitary articles (1 );

joining means for connecting the first web (20) and the third web (39) to each other at respective predetermined zones; and second cutting means (16) for separating in succession from the ribbon (12) the absorbent sanitary articles (1 ) provided with the folded strips (3);

characterized in that it comprises:

assembling means (22) for connecting respective first end portions (35) of the strips (3) in succession and removably to two border portions of the first continuous web (20), in the same plane and on the surface (21 a) of the selfsame first web (20) which will be situated on the outside of the absorbent sanitary articles (1 ), the strips (3) projecting outwards from the first continuous web (20) according to directions substantially perpendicular to the first web (20) itself; folding means (36), located downstream of the assembling means (22), for folding each strip (3) by 180° about its substantially median line, in such a way that its second end portion (37) opposite to the first end portion (35) and connected to the first web (20), adheres to the surface (21 b) of the selfsame first web (20) which will be situated on the inside of the absorbent sanitary articles (1 ); the second end portions (37) of the strips being enclosed between the first web (20) and the third web (39).

5. The apparatus according to claim 4, characterized in that the first path (P1 ) and the second path (P2) are parallel to each other and the first web (20) travels along the paths (P1 , P2) in opposite directions; transmission means (19) being provided to reverse the feed direction of the first web (20) as it passes from the first path (P1 ) to the second path (P2).