WO2014091381A9

WO2014091381A9 - Method for packaging absorbent sanitary articles.

Info

Publication number: WO2014091381A9
Application number: PCT/IB2013/060703
Authority: WO
Inventors: Matteo Piantoni; Alberto Perego
Original assignee: Gdm S.P.A.
Priority date: 2012-12-11
Filing date: 2013-12-06
Publication date: 2014-08-21
Also published as: WO2014091381A1; ITBO20120665A1

Abstract

The method for packaging absorbent sanitary articles (3) according to this invention comprises the steps of folding the articles (3) and subjecting them to mechanical compression in order to reduce their volume; also, around each article (3) a packet (2) is made whose inside forms a chamber (2b) with dimensions such that it can house the article (3) in its folded and compressed condition; the packet (2) is obtained by sequentially inserting the folded articles (3) between two mutually superposed webs (N1, N2) of wrapping material. A sealed chamber (2b) is formed by making, between the two webs (N1, N2), transversal seals which delimit the longitudinal ends of each packet (2), and longitudinal seals along the sides of each pair of consecutive transversal seals. The finished packets (2) are separated from the webs (N1, N2) by cutting the webs (N1, N2) transversely at the transversal seals.

Description

DESCRIPTION

METHOD FOR PACKAGING ABSORBENT SANITARY ARTICLES

Technical field

This invention relates to a method for packaging absorbent sanitary articles.

More specifically, but without thereby limiting its scope, this invention can be usefully applied to the folding and packaging of absorbent sanitary articles both for ladies and for children or incontinent adults.

Background art

As is known, packaging machines for absorbent sanitary articles comprise a unit which folds the articles about folding lines which are transversal to their longitudinal axes.

After being folded, the absorbent sanitary articles are inserted one by one or in groups into respective wrappers by a further unit forming part of the packaging machine.

Often, to reduce the size of the packaged articles, the inside of the wrappers containing the absorbent sanitary articles is subjected to negative pressure while the packages are being formed in order to obtain vacuum packages which are shrunk in size, reducing the volume of the absorbent articles they contain (preferably by around 30%).

The presence of the apparatus used for this purpose on the packaging machines considerably complicates the structure of the packaging machines and increases their cost, while the operation of this apparatus limits machine operating speed.

Also, the absorbent sanitary articles are still in a "bulky" condition when they are inserted into the wrappers and are not reduced in volume until after the wrappers are subjected to negative pressure and, possibly, after the material the wrappers are made of is heat-shrunk. That means the wrappers must be large enough to receive the absorbent articles in their "bulky" condition, which in turn means that large quantities of wrapping material are needed to make the wrappers..

Moreover, the packages thus obtained are decidedly unappealing because the negative pressure applied to the wrappers inevitably causes unattractive creases and wrinkles on the surface of the wrapping material.

Disclosure of the invention

The aim of this invention is to provide a method for packaging absorbent sanitary articles whose implementation does not lead to the drawbacks described above with reference to the prior art and which allows use of less wrapping material than the prior art machines which vacuum pack individual absorbent sanitary articles.

The invention accordingly provides a method for packaging absorbent sanitary 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 is a schematic front view of a packaging machine for making packets of absorbent sanitary articles which implements the method of this invention;

Figures 1 a, 1 b, 1 c and 1 d illustrate four respective configurations adopted by the absorbent sanitary articles and their respective packets while they are being handled by the machine of Figure 1 ;

Figures 2, 2a, 2b and 2c schematically illustrate three respective steps of folding an absorbent sanitary article able to be handled by the machine of Figure 1 , according to three different respective folding styles;

Figures 3-6 schematically illustrate four devices forming part of the packaging machine of Figure 1 . Detailed description of preferred embodiments of the invention

With reference to Figure 1 , the numeral 1 denotes in its entirety a machine for making packets or wrappers 2, each housing (at least) one absorbent sanitary article 3 represented schematically in Figures 2, 2a, 2b and 2c.

The machine 1 comprises a base 4, preferably modular, that is to say, comprising a plurality of sections 5 (precisely six sections, labelled sequentially 5a, 5b, 5c, 5d, 5e, 5f) equipped with respective operating units connectable to each other in pairs as required. Each section 5 is defined frontally by a vertical wall 6 and all the vertical walls 6 on the machine 1 are (preferably) substantially co-planar.

The first section 5a, located on the left-hand side of the machine 1 illustrated in Figure 1 , is a unit 7 of essentially known type for making absorbent articles 3.

The second section 5b, situated immediately to the right of the unit 7 in Figure 1 , is a folding unit 8 which receives the absorbent articles 3 sequentially from the unit 7 and folds them substantially into the shape of a parallelepiped.

The absorbent articles 3 can be folded in many ways. Figure 2, for example, shows a folding style whereby the absorbent article 3 is simply folded into two about a transversal median line. Figure 2a shows a folding style where two opposite end portions 3a of each absorbent article 3 are folded about respective transversal folding lines towards the centre of the absorbent article 3 and the absorbent article 3 is then folded into two about a transversal median line in such a way that the two portions 3a are on the inside of the folded absorbent article 3. Figure 2b, on the other hand, shows a folding style where two opposite end portions 3a of each absorbent article 3 are folded about respective transversal folding lines towards the centre of the absorbent article 3 and the absorbent article 3 is then folded into two about a transversal median line in such a way that the two portions 3a are on the outside of the folded absorbent article 3. Figure 2c shows a folding style whereby the absorbent article 3 is folded into two about a transversal median line and then again into two about the transversal median line of the article which has already been folded once. Lastly, Figure 2d shows a folding style whereby a first end portion 3a of each absorbent article 3 is folded about a first transversal folding line 3b towards the centre of the absorbent article 3 and a second portion 3c, shorter than the first portion 3a, is folded about a second transversal line 3d towards the centre of the selfsame article 3 onto the first portion 3a.

In order to reduce the possibility of jamming, leading to blocking and misalignment, the transfer of the absorbent articles 3 on the folding unit 8 and on the other operating units, described below, is carried out with the absorbent articles 3 oriented in such a way that their free longitudinal ends, if exposed, are directed backwards with reference to the feed direction of the absorbent articles 3 themselves.

A third section 5c, situated immediately to the right of the unit 8 in Figure 1 , is a compression unit 9 which receives the folded absorbent articles 3 sequentially from the unit 8 and performs a compression step by which the articles 3 are compressed, in particular between two juxtaposed belt conveyors 10 whose spacing from each other is less than the thickness of the absorbent articles 3 just folded, in such a way as to better form them substantially into the shape of a parallelepiped and to reduce their volume by squeezing a certain amount of air out of them. The volume is reduced preferably by a quantity substantially equal to 30%, and in any case between 10% and 60%.

A fourth section 5d, situated immediately to the right of the unit 9 in Figure 1 , is a unit 1 1 for reducing the spacing between the absorbent articles 3, which receives the absorbent articles 3 sequentially from the unit 9 and which, with reference to Figure 3, is essentially composed of a pair of rollers 12 counter-rotating about respective horizontal axes 12a perpendicular to the walls 6 of the base 4. The rollers 12 are spaced from each other by a gap just smaller than the thickness of the absorbent articles 3 from the unit 9 and rotate according to a law of motion such that, at least at the instant when an absorbent article 3 comes into contact with the rollers 12 and during the passage of the absorbent article 3 between the selfsame rollers 12, their peripheral speed is less than the feed speed at which the absorbent articles 3 leave the unit 9. As a result, during the passage between the rollers 12, the spacing between the absorbent articles 3 is reduced so that the absorbent articles 3, which are now smaller in size as a result of being folded, and are thus relatively far apart, are drawn closer together.

The absorbent articles 3 which have passed between the rollers 12 then reach a coupling station A where each article 3 is coupled with a wrapping material. More precisely, the articles 3 are inserted between a pair of juxtaposed belt conveyors 13a and 13b, respectively lower and upper, spaced apart by a distance not greater than the thickness of the advancing absorbent articles 3 and able to prevent the absorbent articles 3 from fluffing out again and losing part of the compression previously applied to them.

While they are being inserted between the belt conveyors 13a and 13b, the absorbent articles 3 are inserted between two mutually superposed branches of material in web form, which (in the embodiment of the machine 1 shown in Figure 1 ) consist of two webs N1 , N2 of wrapping material, preferably heat-sealable, below and above them respectively, which are moving alongside the upper horizontal branch of the belt conveyor 13a and the lower horizontal branch of the belt conveyor 13b, respectively. The webs N1 , N2 may be made of the same material, for example polypropylene, but they might also be made of different materials, only one of them a heat-sealable material, while the other (for example, the web N1 , which will form the bottom of the packets 2) might be paper (if necessary, having at least one surface coated with a heat- sealable substance). The webs N1 and N2 come from respective feed units U1 and U2 mounted at an upper section of the machine 1 and able to feed the webs N1 and N2 by unwinding them from reels B in a known manner. Alternatively, the webs N1 and N2 might be obtained by cutting a single web from a single reel longitudinally in half. In another embodiment, not illustrated, a web fed from a single reel might be folded in half longitudinally to form two material web portions or branches wrapping the upper and underside surfaces of the absorbent articles 3, respectively.

The absorbent articles 3 sequentially leaving the belt conveyors 13 pass through a transversal sealing unit 14 forming part of the fourth section 5d and able to sequentially receive the absorbent articles 3 from the spacing reduction unit 1 1 arranged in a row and interposed between the webs N1 and N2. With reference to Figure 4, the transversal sealing unit 14 essentially comprises a pair of rollers 15 counter-rotating about respective horizontal axes 16 perpendicular to the walls 6 of the base 4. The rollers 15 are spaced apart by a gap, which is preferably just smaller than the thickness of the absorbent articles 3 coming from the unit 9, and are equipped on their periphery with at least one respective transversal sealing element 17 which acts in conjunction with a corresponding sealing element 17 on the other roller 15. In use, just after each absorbent article 3 has moved past the unit 14, two sealing elements 17 are drawn closer together and the webs N1 , N2 alongside the absorbent article 3 itself, are sealed along their full width transversely to their direction of feed. Thus, upstream and downstream of each absorbent article 3, a transversal seal is made on a thin elongate strip extending perpendicularly between two lateral edges of the webs N1 , N2. As will become clearer as this description continues, the transversal seals made by the sealing unit 14 delimit the longitudinal ends of the packets 2 and to separate the packets 2 from each consecutive pair of packets 2.

It should be noted that the sealing elements 17 are preferably heat sealers, but they might also be of another type, for example, ultrasound sealers or sealers which use laser beam emitters. Alternatively, traditional adhesive materials or latest generation adhesives might be used.

A fifth section 5e, located immediately to the right of the transversal sealing unit 14 in Figure 1 , comprises a pair of juxtaposed belt conveyors 18a and 18b, respectively lower and upper. The belt conveyors 18a and 18b are spaced apart by a distance not greater than the thickness of the advancing absorbent articles 3 and between them are inserted the absorbent articles 3 which are interposed between the webs N1 , N2 and which have just passed through the transversal sealing unit 14. The belt conveyors 18a and 18b prevent the absorbent article 3 from fluffing out again and losing part of the compression previously applied to them.

The absorbent articles 3 sequentially leaving the belt conveyors 18a and 18b pass through a longitudinal sealing unit 19 forming part of the fifth section 5e and able to sequentially receive the absorbent articles 3 arranged in a row and interposed between the webs N1 and N2.

With reference to Figure 5, the longitudinal sealing unit 19 essentially comprises a pair of rollers 20 counter-rotating about respective horizontal axes 21 perpendicular to the walls 6 of the base 4. The rollers 20 are spaced apart by a gap, which is preferably just smaller than the thickness of the absorbent articles 3 coming from the unit 14, and each of them is equipped on its periphery with two sealing elements 22 which act in conjunction with corresponding sealing elements 22 on the other roller 20 and which are spaced apart by a gap just larger than the width of the absorbent articles 3 arriving at the unit 19. The sealing elements 22 essentially comprise heated annular members and are positioned axially on the respective rollers 20 in such a way as to extend, in pairs, alongside respective lateral edges or sides of the webs N1 and N2.

In use, while the row of absorbent articles 3 interposed between the webs N1 and N2 passes through the longitudinal sealing unit 19, each pair of sealing elements 22 carried by the rollers 20 makes an uninterrupted longitudinal seal on a respective edge zone of the webs N1 and N2, thereby sealing the absorbent articles 3 in respective chambers 2b which are substantially in the shape of parallelepipeds, formed by the webs N1 and N2 and delimited on all four sides by two opposed zones created by the transversal sealing unit 14 and by two opposed zones created by the longitudinal sealing unit 19.

As illustrated schematically in Figure 5, on the peripheral cylindrical surface of the upper roller 20 of the longitudinal sealing unit 19, between the sealing elements 22, there is formed a seat or cavity 45 (at least one) extending towards the axis 21 of the roller 20. Viewed from above, the cavity 45 is similar in shape and size to a folded absorbent article 3, with a depth not greater than that of the absorbent article 3, and its function is to sequentially house at least partly the absorbent articles 3 as they pass between the rollers 20 to ensure they remain centred and in the correct position and keep their shape. The cavity 45 might also be formed on the lower roller 20.

Similar cavities might be made on one or both of the rollers of each pair of rollers 12, 15 forming part of the units 1 1 , 14.

It should be noted that the sealing elements 22 are preferably heat sealers, but they might also be of another type, for example, ultrasound sealers or sealers which use laser beam emitters.

In a variant, not illustrated, of this invention, the positions of the transversal sealing unit 14 and of the longitudinal sealing unit 19 might be changed round and the edge zones of the webs N1 and N2 might thus be sealed to each other before the transversal seals are made.

The row of absorbent articles 3 which has passed through the longitudinal sealing unit 19 is then inserted between a pair of juxtaposed belt conveyors 23a and 23b, respectively lower and upper, forming part of the fifth section 5e, spaced apart by a distance not greater than the thickness of the advancing absorbent articles 3 and able to prevent the absorbent articles 3 from fluffing out again and losing part of the compression previously applied to them.

The transversal sealing unit 14, forming part of the fourth section 5d and the longitudinal sealing unit 19, forming part of the fifth section 5e, define a sealing line L, as will become clearer as this description continues.

More specifically, the sealing line L has an infeed I located downstream of the coupling station A with respect to a predetermined feed direction D of the articles 3.

The absorbent articles 3 which sequentially leave the juxtaposed belt conveyors 23a e 23b pass through a transversal cutting unit 24 forming part of a sixth section 5f and able to sequentially separate the packets 2, each defined by one of the chambers 2b, longitudinally cutting median zones of the above mentioned sealed zones created by the transversal sealing unit 14 on the webs N1 and N2.

In an alternative embodiment of this invention, not illustrated, just after each absorbent article 3 has moved past the unit 14, two sealing elements 17 are drawn closer together and the webs N1 , N2 alongside the absorbent article 3 itself have (at least) two transversal seals made along their full width, side by side and separated by a narrow unsealed surface or strip. In this case, the transversal cutting unit 24 separates each consecutive pair of packets 2, in a manner which will become clearer as this description continues, by cutting the narrow unsealed strip between the two adjacent transversal seals.

In more general terms, therefore, the cut made by the transversal cutting unit 24 to separate the packets 2 from the webs N1 , N2 is made substantially at zones of the webs N1 , N2 where the transversal sealing unit 14 has operated.

With reference to Figure 6, the transversal sealing unit 24 essentially comprises a pair of rollers 25 counter-rotating about respective horizontal axes 26 perpendicular to the walls 6 of the base 4. The rollers 25 are spaced apart by a gap, which is preferably just smaller than the thickness of the absorbent articles 3 coming from the unit 14, and are equipped on their periphery with at least one respective transversal blade 27 which acts in conjunction with a corresponding blade 27 on the other roller 25. Similarly to what is specified above for each pair of rollers 12, 15, the above mentioned cavities 45 might be made on one or both of the rollers of each pair of rollers 25 forming part of the unit 24.

It should be noted that if it is considered necessary or useful, at least part of the edges of the packets 2 (or of the webs N1 and N2 before the packets 2 are separated from the webs N1 and N2 by the transversal cutting unit 24) may be trimmed or folded over and double sealed against the sides adjacent to the edges of the packets 2 themselves. In effect, the edges of the packets 2 have a tendency to wrinkle and their shape can be kept better if they are made to adhere to the sides of the respective packets 2 or if they are resized by trimming them on the at least partly finished packets 2.

The row of packets 2 leaving the transversal cutting unit 24 is then inserted between a pair of juxtaposed belt conveyors 28a and 28b, respectively lower and upper, forming part of the sixth section 5 and spaced apart by a distance not greater than the thickness of the advancing absorbent articles 3.

As illustrated schematically in Figure 1 , the packets 2 which sequentially leave the juxtaposed belt conveyors 28a and 28b may be forwarded, according to preference, towards a station, schematically represented as a block 29 and able to form groups 30a (represented schematically in Figure 2) of packets 2 to be overwrapped, or towards a station, schematically represented as a block 30 and able to perform on the individual packets 2 further operations which are not described because they do not form part of the invention.

It should be noted that according to what is set out above, the absorbent articles 3 may be kept compressed for the entire packaging cycle described, that is to say, as they pass between the pairs of rollers 12, 15, 20 and 25 and between the pairs of belt conveyors 10, 13a and 13b, 18a and 18b, 23a and 23b, 28a and 28b. Also, if desired, the compression applied to the absorbent articles 3 may be progressively increased as they proceed between the pairs of rollers 12, 15, 20 and 25 and between the pairs of belt conveyors 10, 13a and 13b, 18a and 18b, 23a and 23b, 28a and 28b. In any case, the degree of compression applied to the absorbent articles 3 is the factor which determines the maximum internal volume of the packets 2, which are preferably made around the absorbent articles 3 in such a way as not to leave empty spaces in the packets 2 themselves.

It should be noted, lastly, that the compression unit 9, the pairs of rollers 12, 15, 20 and 25 and the pairs of belt conveyors 10, 13a and 13b, 18a and 18b, 23a and 23b, 28a and 28b also constitute mechanical compression means for the articles 3. By mechanical compression is meant compression achieved by squeezing the articles 3 between pairs of belts or rollers.

Also, compression may start at least at the infeed I of the sealing line L downstream of the coupling station A with respect to the predetermined direction D or upstream of the coupling station A with respect to the predetermined direction D and the articles 3 remain in the compressed condition as they are fed towards the infeed I of the sealing line L.

Also, in an embodiment of the invention, not illustrated, it might be possible to associate a coupon (not illustrated) or other type of sheet material with each absorbent article 3, preferably when the article is inserted between the webs N1 and N2.

It should also be noted that if the packets 2 sequentially leaving the belt conveyors 28a and 28b are forwarded to the above mentioned station 29 for forming groups 30a (Figure 2) of packets 2 to be overwrapped, it may be useful to make at least a hole in the packets 2, after the packets 2 have been completed, in order to put the inside of them in communication with the surrounding environment. This may be useful in the case where the groups 30a of packets 2 are strongly compressed before being overwrapped to prevent the packets 2 from bursting if the air inside them is compressed without being able to escape.

It should be noted, lastly, that subjecting the absorbent sanitary articles to the aforementioned mechanical compression while they are being packaged and as a result of the way the packets 2 are made, the overall size of the absorbent articles 3 is considerably reduced and the quantity of wrapping material needed is minimized.

Claims

1 . A method for packaging absorbent sanitary articles, comprising the steps of feeding said articles (3) towards a coupling station (A) for coupling each article (3) with a wrapping material, feeding said articles (3) together with the wrapping material along a predetermined direction (D) towards the infeed (I) of a sealing line (L), subjecting said articles (3) to compression, reducing their volume by a predetermined quantity, feeding said articles (3) along the sealing line (L) for performing a sealing step, making around each article (3) a sealed packet (2) whose inside forms a chamber (2b) with dimensions such that it can house the absorbent sanitary article (3) in its compressed condition.

2. The method according to claim 1 , characterized in that the compression step starts at least at the infeed (I) of the sealing line (L), downstream of the coupling station (A) with respect to the predetermined direction (D).

3. The method according to claim 1 or 2, characterized in that the compression step starts upstream of the coupling station (A) with respect to the predetermined direction (D) and the articles (3) are fed towards the infeed (I) of the sealing line (L) while remaining in the compressed condition.

4. The method according to any one of the preceding claims 1 to 3, characterized in that said articles (3) are fed along the sealing line (L) while compression is maintained both on the wrapping material and on the articles (3) themselves.

5. The method according to any one of the preceding claims 1 to 4, characterized in that the compression step of said articles (3) occurs gradually and achieves the reduction in their volume by said predetermined quantity before completion of the sealing step.

6. The method according to any one of the preceding claims 1 to 5, characterized in that the compression step of said articles (3) is gradual and achieves the reduction in their volume by said predetermined quantity before the start of the sealing step.

7. The method according to any one of the preceding claims 1 to 6, characterized in that the step of subjecting said articles (3) to compression causes a reduction in their volume by a quantity of between 10% and 60%.

8. The method according to any one of the preceding claims 1 to 7, characterized in that the step of subjecting said articles (3) to compression causes a reduction in their volume by a quantity substantially equal to 30%.

9. The method according to any one of the preceding claims 1 to 8, characterized in that the compression step is carried out mechanically by making the articles (3) pass sequentially through juxtaposed mechanical compression means with a minimum spacing from each other which is less than the thickness of the absorbent articles (3).

10. The method according to any one of the preceding claims 1 to 9, characterized in that a packet (2) is made around each absorbent sanitary article (3) by carrying out the steps of sequentially inserting the folded articles (3) between two mutually superposed wrapping material web branches (N1 , N2); making transversal seals between the two web branches (N1 , N2), at a transversal sealing unit (14), for delimiting the longitudinal ends of each packet (2); making longitudinal seals on the sides of said web branches (N1 , N2), at a longitudinal sealing unit (19); the longitudinal seals, together with each pair of consecutive transversal seals, forming a sealed chamber (2b) containing an absorbent sanitary article (3); transversally cutting the web branches (N1 , N2) cyclically, using a transversal cutting unit (24), in order to separate the packets (2) from the web branches (N1 , N2) substantially at zones where the transversal sealing unit (14) has operated.

1 1 . The method according to any one of the preceding claims 1 to 10, characterized in that a packet (2) is made around each absorbent sanitary article (3) by sequentially inserting the folded articles (3) between two mutually superposed wrapping material web branches (N1 , N2) unwound from a single reel and then folded in half longitudinally to form the two web branches (N1 , N2).

12. The method according to any one of the preceding claims 1 to 1 1 , characterized in that it comprises the further step of reducing the spacing between the folded articles (3).

13. The method according to any one of the preceding claims 1 to 12, characterized in that during the entire packaging cycle the articles (3) are kept compressed as a result of their passage through pairs of rollers (12, 15, 20 and 25) positioned respectively at the spacing reduction unit (1 1 ), at the transversal sealing unit (14), at the longitudinal sealing unit (19) and at the transversal cutting unit (24), and through pairs of belt conveyors (10, 13a and 13b, 18a and 18b, 23a and 23b, 28a and 28b); the rollers (12, 15, 20 and 25) and the belt conveyors (10, 13a and 13b, 18a and 18b, 23a and 23b, 28a and 28b) of each pair being separated from each other by gaps slightly smaller than the thickness of the articles (3).

14. The method according to any one of the preceding claims 1 to 13, characterized in that the articles (3) are gradually compressed as they pass through the pairs of rollers (12, 15, 20 and 25) and the pairs of belt conveyors (10, 13a and 13b, 18a and 18b, 23a and 23b, 28a and 28b).

15. The method according to any one of the preceding claims 1 to 14, characterized in that it comprises keeping the absorbent articles (3) in the correct and centred position while they are being packaged between the wrapping material web branches (N1 , N2), placing each folded absorbent article (3) in succession inside a seat (45) provided on at least one of each pair of rollers (12, 15, 20, 25).

16. The method according to any one of the preceding claims 1 to 15, characterized in that the transfer of the articles (3) along the packets (2) production line is preferably performed by positioning the articles (3) with their free longitudinal end edges facing the opposite way to their direction of feed.

17. The method according to any one of the preceding claims 1 to 16, characterized in that after the sealed packets (2) defining said chambers (2b) have been made, each of them is put in communication with the outside environment by making at least a hole in each packet (2).