Patent Description:
In particular, the invention relates to a method for producing absorbent sanitary articles comprising a central body and at least one pair of side panels fixed to at least one end region of the central body.

The invention was developed in particular with a view of producing absorbent sanitary articles for incontinent adults, in particular, for persons suffering from obesity.

Absorbent sanitary articles for incontinent adults generally comprise a central body or chassis with a rectangular shape elongated in a longitudinal direction and having a rear waist section, a front waist section and a crotch section extending between the rear waist section and the front waist section. The central body usually comprises an absorbent core sandwiched between a liquid-permeable topsheet which faces the wearer's skin in use, and a liquid-impermeable backsheet which faces the wearer's clothing in use. The central body may include an acquisition and distribution layer arranged between the topsheet and the absorbent core. The central body may also comprise a pair of elastic leg cuffs, which extend along the topsheet in a longitudinal direction, and which adhere to the user's legs in use.

Absorbent sanitary articles for incontinent adults generally comprise a pair of rear side panels and, optionally, a pair of front side panels. The rear side panels and, if provided, the front side panels have respective proximal sides fixed to corresponding side edges of the rear or front section of the central body and in the condition of use they extend laterally outwards with respect to the central body. The side panels are generally provided at the respective distal ends with closing elements for closing the sanitary article around the user's waist. The side panels may have inclined sides to conform to the user's legs. For example, the side panels may have a trapezoidal shape as described in <CIT>.

Absorbent sanitary articles for obese adults are typically very large in size. For example, the central body may have a length of about one meter and a width of about <NUM>, so that the circumference of the waistband may reach dimensions in the order of <NUM> and above. In these cases, the side panels may have dimensions in the transversal direction that can reach <NUM> - <NUM> for each panel.

The large dimensions of the side panels pose various problems both from the point of view of the costs of the raw material, and from the point of view of the production methods.

<CIT> by the same applicant describes a method for producing absorbent sanitary articles wherein the side panels are partially overlapped and joined together in a provisional manner, and are fixed to two side topsheet webs that are subsequently joined to a central topsheet web.

<CIT> describes a method for producing absorbent articles provided with side panels, which envisages longitudinally folding a continuous web in a generally Z-shaped configuration, separating single folded side panels from said Z-folded continuous web and attaching the folded side panels at predetermined intervals on a chassis tape.

In the state of the art there remains the need to provide absorbent sanitary articles with large side panels, which have lower costs of the raw material necessary for producing the side panels, and which can be produced with more efficient and economical equipment and production processes.

The object of the present invention is to provide a method for producing absorbent sanitary articles that satisfies the aforesaid need, and that solves the problems of the prior art.

According to the present invention, this object is achieved by a method for producing absorbent sanitary articles having the characteristics of claim <NUM>.

Preferred embodiments of the invention form the subject of the dependent claims.

The claims form an integral part of the technical disclosure provided in relation to the invention.

The invention will now be described with reference to the attached drawings, given purely by way of nonlimiting example, wherein:.

With reference to <FIG>, numeral <NUM> indicates an absorbent sanitary article. The absorbent sanitary article <NUM> comprises a central body <NUM> or chassis having an elongated shape along a longitudinal axis A. The central body <NUM> may have a rectangular shape, as illustrated in <FIG> with two straight side edges <NUM> and parallel to the longitudinal axis A. Alternatively, the two side edges <NUM> may be shaped to conform to the user's legs.

The central body <NUM> has a rear waist section <NUM>, a front waist section <NUM> and a crotch section <NUM> which extends between the rear waist section <NUM> and the front waist section <NUM> and which - in use - is arranged between the legs of the user.

The central body <NUM> comprises an absorbent core <NUM> sandwiched between a liquid-permeable topsheet <NUM>, which faces the wearer's skin in use and a liquid-impermeable backsheet <NUM>, which faces the wearer's clothing in use. The central body <NUM> may include an acquisition and distribution layer <NUM> arranged between the topsheet <NUM> and the absorbent core <NUM>.

The central body <NUM> may also comprise two leg cuffs <NUM>, which extend longitudinally on the topsheet <NUM>. Each leg cuff <NUM> comprises a non-woven strip having an outer edge <NUM> fixed to a corresponding side edge <NUM> of the central body <NUM> and an inner edge <NUM> in which at least one elastic thread tensioned in the longitudinal direction is arranged, so that - in use - the inner edge <NUM> of each leg cuff <NUM> adheres elastically against the user's legs.

The absorbent sanitary article <NUM> comprises first and second rear side panels <NUM>', <NUM>" which - in the extended configuration of the absorbent sanitary article <NUM> - extend in a transverse direction towards the outside with respect to the central body <NUM>.

The first and second rear side panels <NUM>', <NUM>" have respective proximal edges <NUM> and respective distal edges <NUM>. The first and second rear side panels <NUM>', <NUM>" may have transverse edges <NUM> shaped to conform to the user's legs in the condition of use. In possible embodiments, the rear side panels <NUM> may have a trapezium shape, in which the proximal edges <NUM> and the distal edges <NUM> form the major bases and the minor bases of the trapeziums, respectively.

The proximal edges <NUM> of the first and second rear side panels <NUM>', <NUM>" are fixed to corresponding side edges <NUM> of the rear waist section <NUM> of the central body <NUM>. The attachment area between the proximal edges <NUM> of the first and second rear side panels <NUM>', <NUM>" and the side edges <NUM> of the rear section <NUM> is indicated by <NUM> in <FIG>.

With reference to <FIG> and <FIG>, in a possible embodiment, the proximal edges <NUM> of the first and second rear side panels <NUM>', <NUM>" may be fixed between corresponding outer edges of the backsheet <NUM> and the outer edges <NUM> of the leg cuffs <NUM>. The fastening may be carried out by welding (for example, thermo-compression or ultrasonic) or by glue.

In a possible embodiment, the proximal edges <NUM> of the first and second rear side panels <NUM>', <NUM>" may be fixed between corresponding outer edges of the backsheet <NUM> and of the topsheet <NUM>.

The absorbent sanitary article <NUM> comprises at least one extension band <NUM>', <NUM>" having a proximal edge <NUM> fixed to the distal edge <NUM> of a side panel <NUM>', <NUM>" and a distal edge <NUM> to which at least one closing element <NUM> is fixed.

In the embodiment illustrated in the figures, the absorbent sanitary article <NUM> comprises first and second extension bands <NUM>', <NUM>" having respective proximal edges <NUM> fixed to respective distal edges <NUM> of respective first and second side panels <NUM>', <NUM>".

Below, reference will be made to the embodiment in which the absorbent sanitary article <NUM> comprises two extension bands <NUM>', <NUM>" but it is understood that what is described applies equally to the case wherein the absorbent sanitary article <NUM> comprises only one extension band <NUM>', <NUM>".

The fastening areas between the proximal edges <NUM> of the first and second extension bands <NUM>', <NUM>" and the respective distal edges <NUM> of the side panels <NUM>', <NUM>" are indicated by <NUM>. The fastening of the first and second extension bands <NUM>', <NUM>" to the respective first and second side panels <NUM>', <NUM>" may be carried out by welding, such as, for example, thermo-compression or ultrasonic welding, or by glue.

In a possible embodiment, the first and second rear side panels <NUM>', <NUM>" and the first and second extension bands <NUM>', <NUM>" may be formed of different materials. In a possible embodiment, the first and second rear side panels <NUM>', <NUM>" may be formed of non-elastic material, for example from one or more non-woven layers. In a possible embodiment, the first and second extension bands <NUM>', <NUM>" may be made of elastic material, extensible in a transverse direction B. Each extension band <NUM>', <NUM>" may be formed from an elastic laminate comprising at least one elastic element sandwiched between two non-woven layers. In a resting condition, each of the first and second extension bands <NUM>', <NUM>" may have pleated outer surfaces. The proximal edge <NUM> and the distal edge <NUM> of each extension band <NUM>', <NUM>' may be non-elastic.

Each extension band <NUM>', <NUM>" may have the shape of a strip elongated in a transverse direction, with two transverse sides <NUM> parallel to each other.

The closing elements <NUM> fixed to the distal ends <NUM> of the extension bands <NUM>', <NUM>" may be closing elements with micro-hooks or adhesives, which allow a surface closure to be carried out with complementary closing elements to close the sanitary absorbent article <NUM> around the user's waist.

With reference to <FIG>, the absorbent sanitary article <NUM> may comprise a pair of front side panels <NUM>, which in the extended configuration of the absorbent sanitary article <NUM> extend in a transverse direction towards the outside with respect to the central body <NUM>.

The front side panels <NUM> may be fixed to corresponding side edges <NUM> of the front section <NUM> of the central body <NUM>. The front side panels <NUM> may have outer surfaces configured to establish a surface closure with the closing elements <NUM>. In the case wherein the absorbent sanitary article <NUM> is not provided with front side panels <NUM>, the closing elements <NUM> may establish surface closure with an outer surface of the front section <NUM> of the central body <NUM>. According to a further embodiment, both in the case wherein the absorbent sanitary article <NUM> is provided with front side panels <NUM>, and in the case wherein the absorbent sanitary article <NUM> is not provided with front side panels <NUM>, the absorbent sanitary article <NUM> may be provided with a front panel (frontal tape) fixed centrally on the outer surface of the absorbent sanitary article <NUM> facing outwards in use, or rather, towards the clothing. According to this further embodiment, the front panel is configured to establish a surface closure with the closing elements <NUM>.

In the extended position, each of the extension bands <NUM>', <NUM>" may have a dimension, at rest, in the transverse direction B of between <NUM> and <NUM>.

The distance at rest in the transverse direction B between the distal edges <NUM> of the side panels <NUM>', <NUM>" may be between <NUM> and <NUM>. Consequently, the overall width at rest in the transverse direction B of the rear waistband of the absorbent sanitary article <NUM> may be between <NUM> and <NUM>.

<FIG> and <FIG> schematically illustrate two embodiments of an absorbent sanitary article <NUM> in folded positions. The folded positions illustrated in <FIG> and <FIG> are the positions in which the absorbent sanitary articles <NUM> are found at the outlet of a production line, and in the packages in which the absorbent sanitary articles <NUM> are marketed.

In both embodiments of <FIG> and <FIG>, the first and second side panels <NUM>', <NUM>" and the first and second extension bands <NUM>', <NUM>" are folded over the rear section <NUM> of the central body.

With reference to <FIG>, in the folded position, the first and second side panels <NUM>', <NUM>" are folded around respective first fold lines <NUM> with respect to the respective proximal edges <NUM> fixed to the central body <NUM> and have respective first and second panel flaps <NUM>', <NUM>".

The first and second extension bands <NUM>', <NUM>" are folded about respective second fold lines <NUM> with respect to the respective proximal edges <NUM> fixed to the respective first and second side panels <NUM>', <NUM>", and have respective first and second band flaps <NUM>', <NUM>" overlapped on respective first and second panel flaps <NUM>', <NUM>".

The first panel flap <NUM>' is overlapped on the topsheet <NUM> and the leg cuffs <NUM>. The second panel flap <NUM>" is overlapped on the first band flap <NUM>'.

The first and second panel flaps <NUM>', <NUM>" and the first and second band flaps <NUM>', <NUM>" are held in the folded positions by temporary joining zones, which may be released with minimal peel force and without damaging the elements between which they extend. Temporary bonds with these characteristics are well known in the absorbent sanitary article industry and may be formed by light welds (known in the art as "technical welds") or by small amounts of glue.

In a possible embodiment, first temporary joining zones <NUM> extend between the first and second band flaps <NUM>', <NUM>" and the respective first and second panel flaps <NUM>', <NUM>".

In a possible embodiment, at least one second temporary joining zone <NUM> extends between the second band flap <NUM>" and the first panel flap <NUM>', through the second panel flap <NUM>" and through the first band flap <NUM>'.

In a possible embodiment, at least one third temporary joining zone <NUM> extends between the second band flap <NUM>" and the topsheet <NUM>, through the second panel flap <NUM>", through the first band flap <NUM>' and through the first panel flap <NUM>'. In the example illustrated in <FIG>, two third temporary joining zones <NUM> are provided located on opposite sides with respect to the longitudinal axis A of the central body <NUM> of the absorbent sanitary article <NUM>.

A second embodiment of an absorbent sanitary article in a folded configuration is illustrated in <FIG>. The elements corresponding to those previously described are indicated with the same numerical references. With respect to the embodiment of <FIG>, the first and second band flaps <NUM>', <NUM>" are further Z-folded, and each of the band flaps <NUM>', <NUM>" has three flap sections <NUM>', <NUM>" overlapped on each other.

Also in the embodiment of <FIG>, the first and second panel flaps <NUM>', <NUM>" and the first and second band flaps <NUM>', <NUM>" are held in the folded positions by temporary joining zones <NUM>, <NUM>, <NUM> as previously described. In addition to the temporary joining zones <NUM>, <NUM>, <NUM> arranged as described in relation to <FIG>, in the embodiment of <FIG> fourth temporary joining zones <NUM> may be provided, which extend between the first and second band flaps <NUM>', <NUM>" and the respective first and second panel flaps <NUM>', <NUM>" through the respective flap sections <NUM>', <NUM>" overlapped on each other.

It can be noted that in both embodiments of <FIG> and <FIG>, the closing elements <NUM> are uncovered and adjacent to the side edges <NUM> of the central body <NUM>. To open the absorbent sanitary article into the position of use, it is sufficient to grasp the closing elements <NUM> and pull them in opposite directions outwards. In this way, the temporary joining zones <NUM>, <NUM>, <NUM>, <NUM>, which hold the first and second panel flaps <NUM>', <NUM>" and the first and second band flaps <NUM>', <NUM>" in the folded position yield, and the side panels <NUM>', <NUM>" and the respective first and second extension bands <NUM>', <NUM>" are arranged in the open position shown in <FIG>.

Despite the considerable extension of the rear waistband in the open position (which can be between <NUM> and <NUM>), in the folded configuration the absorbent sanitary article has a width equal to the width of the central body, which may be between <NUM> and <NUM>.

<FIG>, <FIG> and <FIG> schematically illustrate successive cross-sections of a method for producing absorbent sanitary articles <NUM> according to the present invention.

With reference to <FIG>, the method envisages feeding a continuous laminate <NUM> in the direction of its longitudinal axis X by a first feeding device <NUM>. The continuous laminate <NUM> may be stretchable elastically in a transverse direction perpendicular to the longitudinal axis X.

A continuous closing tape <NUM>, such as a micro-hook tape, is transversely cut in a first cut-and-slip unit <NUM> to form a row of closing elements (indicated by <NUM> in <FIG>). The first cut-and-slip unit <NUM> applies the closing elements along the side edges of the continuous laminate <NUM> in spaced apart positions along the longitudinal axis X. The closing elements may be fixed to the continuous laminate <NUM> in a first welding unit <NUM>.

Then, the continuous laminate <NUM> is cut in the longitudinal direction in a first longitudinal cutting unit <NUM> to form two separate continuous webs <NUM>, each of which has an array of closing elements at an outer edge.

The two continuous webs <NUM> are folded in the longitudinal direction in a longitudinal folding unit <NUM> so as to form on each of the two continuous webs <NUM> a single U-shaped lateral fold (embodiment of <FIG>) or a U-shaped lateral fold and a central Z-fold (embodiment of <FIG>).

After having made the folds, the folded flaps of the two continuous webs <NUM> may be subjected to a compression step carried out in a compression unit <NUM>.

After having made the folds, the two continuous webs <NUM> may be reversed in a first reversal unit <NUM>, so that after the reversal the two continuous webs <NUM> have the respective closing elements along their respective edges facing each other.

Subsequently, the two continuous webs <NUM> are cut transversely in a second cut-and-slip unit <NUM>, so as to form two rows of folded extension bands, indicated with <NUM>', <NUM>" in <FIG> and <FIG>.

The method envisages feeding a continuous web <NUM> by a second feeding unit <NUM>. The continuous web <NUM> may be of non-elastic material, for example, of non-woven fabric. The second cut-and-slip unit <NUM> applies pairs of folded extension bands onto the continuous web <NUM> at positions spaced apart from each other in the longitudinal direction. The pairs of folded extension bands are fixed to the continuous sheet <NUM> along respective outer edges. This fastening may be carried out by glue, which can be applied to the two continuous webs <NUM> upstream of the second cut-and-slip unit <NUM> by a glue dispensing device <NUM>. Alternatively, the pairs of folded extension bands may be fastened to the continuous web <NUM> by thermal or ultrasonic welding.

The pairs of folded extension bands fastened along their proximal edges to the continuous web <NUM> are then joined to the continuous web <NUM> in a temporary welding unit <NUM> to form the temporary joining zones indicated by <NUM> and <NUM> in <FIG> and <FIG>.

Then, the continuous web <NUM> is cut in the longitudinal direction in a second longitudinal cutting unit <NUM> so as to form two separate continuous webs <NUM>, each of which has a respective row of folded extension bands fixed to one of its outer edges and joined to it by temporary joining zones.

With reference to <FIG>, the two continuous webs <NUM> may be reversed in a second inversion unit <NUM>, so that after the inversion the two continuous webs <NUM> have the edges along which the folded extension bands are fixed facing each other.

Then, the two continuous webs <NUM> are cut in respective cutting units <NUM> so as to form two rows of side panels, indicated with <NUM>', <NUM>" in <FIG>, each with a respective folded extension band <NUM>', <NUM>" fixed to one of its edges.

Then, each second side panel <NUM>" with the respective second folded extension band <NUM>" fixed thereto is partially overlapped on a first side panel <NUM>' with the respective first folded extension band <NUM>' fixed thereto. This overlapping may be done on an anvil wheel of a welding unit <NUM>. In the welding unit <NUM>, the first and second side panels <NUM>', <NUM>" and the respective folded extension bands <NUM>', <NUM>" fixed thereto and overlapped on each other may be subjected to welding operations to form the temporary joining zones <NUM> (<FIG> and <FIG>), which join together the second band flap <NUM>" and the first panel flap <NUM>' through the second panel flap <NUM>" and through the first band flap <NUM>'.

The array of overlapping side panels thus formed is fed to a repitching unit <NUM>, which spaces apart the side panels in the longitudinal direction.

A leg cuff forming unit <NUM> forms two continuous strips of leg cuffs <NUM> provided with respective elastic bands and spaced apart from each other in the transverse direction.

The repitch unit <NUM> applies the array of side panels overlapped on each other on the two continuous strips of leg cuffs <NUM>. The proximal edges of the first and second side panels <NUM>', <NUM>' may be glued or welded to the respective continuous strips of leg cuffs <NUM>.

Then, a continuous topsheet web <NUM> is fixed between the two continuous strips of leg cuffs <NUM> to form a continuous composite web <NUM> including the continuous strips of leg cuffs <NUM>, the continuous topsheet web <NUM> and an array of first and second side panels <NUM>', <NUM>" with respective folded extension bands <NUM>', <NUM>".

In a possible embodiment, the proximal edges of the first and second side panels <NUM>', <NUM>" may be fixed by glue or by welding to respective outer edges of the topsheet <NUM>.

With reference to <FIG>, the continuous composite web <NUM> is made to advance in the X direction and acquisition and distribution layers may be applied thereon, indicated with <NUM> in <FIG>, formed by a unit <NUM>.

At least one forming unit <NUM> forms absorbent cores, indicated by <NUM> in <FIG>, which advance spaced apart in the X direction on a conveyor <NUM>. In the illustrated example, two forming units <NUM> are provided, which form two rows of overlapped absorbent cores.

The absorbent cores are sandwiched between the continuous composite web <NUM> and the continuous backsheet web <NUM> to form a continuous absorbent structure <NUM>. Continuous leg elastic bands <NUM> may be applied between the continuous composite web <NUM> and the continuous backsheet web <NUM>.

The side edges of the continuous strips of leg cuffs <NUM> may be secured to corresponding side edges of the continuous backsheet web <NUM> so as to fasten the proximal edges <NUM> of the side panels <NUM>', <NUM>" between the side edges of the continuous strips of leg cuffs <NUM> and the side edges of the continuous backsheet web <NUM>.

In a possible embodiment, the side edges of the continuous strips of leg cuffs <NUM> may be fixed to corresponding side edges of the continuous topsheet web <NUM> and the side edges of the continuous topsheet <NUM> and backsheet <NUM> webs may be fixed to each other so as to fix the proximal edges <NUM> of the side panels <NUM>', <NUM>" between the side edges of the continuous topsheet <NUM> and backsheet <NUM> webs.

Then, the continuous absorbent structure <NUM> is cut to form individual absorbent sanitary articles <NUM>.

Claim 1:
A method for producing absorbent sanitary articles, comprising:
- forming extension bands (<NUM>', <NUM>") having respective proximal edges (<NUM>), respective distal edges (<NUM>) to which respective closing elements (<NUM>) are fixed, and respective band flaps (<NUM>', <NUM>"),
- overlapping said extension bands (<NUM>', <NUM>") on a continuous web (<NUM>) in spaced apart positions in a longitudinal direction and fixing the proximal edges (<NUM>) of said extension bands (<NUM>', <NUM>") to said continuous web (<NUM>),
- connecting said band flaps (<NUM>', <NUM>") to said continuous web (<NUM>) by first temporary joining zones (<NUM>),
- cutting said continuous web (<NUM>) so as to form side panels (<NUM>', <NUM>") having respective proximal edges (<NUM>) and respective distal edges (<NUM>), each with a respective extension band (<NUM>', <NUM>") fixed to its distal edge (<NUM>),
- fixing the proximal edges (<NUM>) of said side panels (<NUM>', <NUM>") alongside edges of a continuous composite structure (<NUM>) including a continuous topsheet (<NUM>), a continuous backsheet (<NUM>) and a plurality of absorbent cores (<NUM>) enclosed between the continuous topsheet (<NUM>) and the continuous backsheet (<NUM>), and
- cutting said continuous composite structure (<NUM>) so as to form individual absorbent sanitary articles (<NUM>).