Patent Description:
The present invention also relates to a method for producing absorbent sanitary articles.

An absorbent sanitary article typically has a structure that comprises a central body or chassis having rear and front sections. The chassis normally includes a permeable topsheet intended to come into contact with the user's skin when the article is worn, an impermeable backsheet and an absorbent core sandwiched between the topsheet and the backsheet. The rear and front sections of the chassis are normally closed around the user's waist by means of hook-and-loop fasteners, better known as Velcro© fastening devices.

The rear and front sections may be elasticized. <CIT> and <CIT> disclose methods for bonding elastic parts under tension to an advancing carrier, which may be used for elasticizing the waist sections of absorbent sanitary articles. The methods disclosed in these documents provide: advancing a carrier substrate, advancing a continuous elastic substrate, cutting an elastic part from the continuous elastic substrate, stretching the elastic part in a cross direction, positioning the elastic part on the carrier substrate, and adhesively bonding a stretched central region of the elastic part with the carrier substrate, and mechanically bonding end regions of the elastic part with the carrier substrate.

<CIT> discloses a method and apparatus for applying a pair of stretchable outer ears and a gathered stretchable waist band to an absorbent article using a single piece of elastic material which forms both the outer ears and the elastic waist band. The solution disclosed in <CIT> is advantageous for reducing cost and complexity of the process and converting machines in that the elastic waist bands and the elastic side panels are applied as unitary components. However, there remains a need to provide the absorbent sanitary articles with improved capacity to contain body exudates and to prevent leakage of body exudates from the waist regions. <CIT> also discloses an absorbent article having a C-shaped pocket, whereby the central portion of the rear waistband is not elasticised.

The object of the present invention is to provide an absorbent sanitary article which overcomes the problems of the prior art.

More specifically, an object of the present invention is to provide absorbent sanitary articles which have an improved capacity of retention of body exudates and reduced leakage from the waist regions.

According to the invention, this object is achieved by an absorbent sanitary article having the features of claim <NUM>.

According to another aspect, the invention relates to a method for producing absorbent sanitary articles having the features of claim <NUM>.

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

The present invention will now be described with reference to the attached drawings, provided purely by way of non-limiting example, wherein:.

It should be appreciated that the attached drawings are schematic and not to scale with respect to real products. Various figures may not be represented in the same scale. Also, in various figures some elements may not be shown to better show other elements.

With reference to <FIG> and <FIG>, numeral <NUM> indicates an absorbent sanitary article according to the present invention. <FIG> shows the absorbent sanitary article <NUM> in the configuration in which it is worn, and <FIG> shows the absorbent sanitary article <NUM> in a flat configuration.

The absorbent sanitary article <NUM> comprises a chassis <NUM> elongated along a longitudinal axis X. The chassis <NUM> has two side edges <NUM>, and rear and front waist sections <NUM>, <NUM>. The rear and front waist sections <NUM>, <NUM> have respective transverse edges <NUM>, <NUM>. The rear and front waist sections <NUM>, <NUM> in use are closed around the user's waist. The rear and front waist sections <NUM>, <NUM> may be not elastic. A crotch section <NUM> extends between the rear and front waist sections <NUM>, <NUM>. In use, the crotch section <NUM> is arranged between the legs of the user.

The chassis <NUM> may have a rectangular shape, with two straight side edges <NUM> parallel to the longitudinal axis X. In a possible embodiment, the side edges <NUM> may be shaped to conform to the legs of the user in the configuration in which the absorbent sanitary article <NUM> is worn, such that in a flat configuration the absorbent sanitary article <NUM> has substantially an hourglass shape.

The chassis <NUM> comprises a topsheet <NUM> made of a permeable material having an outer surface which, in use, is in contact with the user's skin, an impermeable backsheet <NUM>, and an absorbent core <NUM> set between the topsheet <NUM> and the backsheet <NUM>.

The absorbent sanitary article <NUM> comprises at least one transverse elastic element <NUM> elastically stretchable in a transverse direction Y orthogonal to the longitudinal axis X. In <FIG> the transverse elastic element <NUM> is shown in an exploded position with respect to the chassis <NUM>. The transverse elastic element <NUM> is applied on the outer surface of the topsheet <NUM> in at least one of the rear and front waist sections <NUM>, <NUM>. In a possible embodiment, the absorbent sanitary article <NUM> may comprise rear and front transverse elastic elements <NUM> attached respectively to the rear and front sections <NUM>, <NUM> of the chassis <NUM>.

The transverse elastic element <NUM> includes an elastic gasketing portion <NUM> and two elastic side panels <NUM> formed as a unitary component. The elastic gasketing portion <NUM> extends between the two side edges <NUM> of the chassis <NUM> and two elastic side panels <NUM> extend transversally outwardly beyond respective side edges <NUM> of the chassis <NUM>.

The transverse elastic element <NUM> may comprise two non-elastic portions <NUM>, each extending between a respective elastic side panel <NUM> and the elastic gasketing portion <NUM>.

With reference to <FIG>, the transverse elastic element <NUM> may comprise two non-elastic outer layers <NUM>, <NUM> and at least one transversally stretchable elastic film <NUM>, <NUM> sandwiched between the two non-elastic outer layers. The transverse elastic element <NUM> may comprise a central transversally stretchable elastic film <NUM> extending between the two non-elastic portions <NUM> and two lateral transversally stretchable elastic films <NUM> extending laterally outwardly of the respective non-elastic portions <NUM>.

The two non-elastic outer layers <NUM>, <NUM> may be joined to the transversally stretchable elastic films <NUM>, <NUM> by ultrasonic welding, thermocompression welding or by glue. In a possible embodiment, the two non-elastic outer layers <NUM>, <NUM> may be joined to the transversally stretchable elastic films <NUM>, <NUM> by a pattern of ultrasonic spot welds. The spot welds may form through holes in the transversally stretchable elastic films <NUM>, <NUM> and the two non-elastic outer layers <NUM>, <NUM> may be fixed to each other through the through holes. In the non-elastic portions <NUM> the transversally stretchable elastic films <NUM>, <NUM> are not present and the two non-elastic outer layers <NUM>, <NUM> are fixed directly to each other.

The two elastic side panels <NUM> may have respective non-elastic distal portions <NUM> carrying respective fastening formations <NUM>, e.g. micro-hook fastening formations.

The transverse elastic element <NUM> may comprise a non-elastic outer layer <NUM> of non-woven material and a non-elastic outer layer <NUM> of impermeable plastic material. The non-elastic outer layer <NUM> of impermeable plastic material may forms the surface of the elastic gasketing portion <NUM> facing the outer surface of the topsheet <NUM>. The non-elastic outer layer <NUM> of non-woven material may form the surface of the elastic gasketing portion <NUM> which in use is in contact with the user's skin.

In a possible embodiment, the elastic gasketing portion <NUM> and the two elastic side panels <NUM> may have different transverse elasticity. The elasticity may be expressed by the percentage difference between the dimension of an element in a condition of maximum elongation and at rest. In a possible embodiment, each of the two elastic side panels <NUM> may have a transverse elasticity comprised between <NUM>-<NUM>%. In a possible embodiment, the elastic gasketing portion <NUM> may have a transverse elasticity comprised between <NUM>-<NUM>%. The different elasticity between the elastic gasketing portion <NUM> and the two elastic side panels <NUM> may be obtained by providing elastic films <NUM>, <NUM>, with different elastic properties and/or by providing different welding patterns between the elastic films <NUM>, <NUM> and the non-elastic outer layers <NUM>, <NUM>.

With reference to <FIG>, the or each transverse elastic element <NUM> is attached to the rear and/or front waist section <NUM>, <NUM> the chassis <NUM> along a C-shaped attachment profile <NUM> including two opposite longitudinal portions <NUM> adjacent to respective side edges <NUM> of the chassis <NUM> and a transverse outer portion <NUM> adjacent to one of said rear and front transverse edges <NUM>, <NUM> of the chassis <NUM>.

The C-shaped attachment profile <NUM> may be formed by glue or by welding or a combination thereof. With reference to <FIG>, in a possible embodiment, the transverse outer portion <NUM> of the C-shaped attachment profile <NUM> may be formed by glue and the two opposite longitudinal portions <NUM> may be formed by welding <NUM>, e.g. ultrasonic welding. In a possible embodiment, the two opposite longitudinal portions <NUM> of the C-shaped attachment profile <NUM> may include both glue and welding <NUM>.

The two non-elastic portions <NUM> of the transverse elastic element <NUM> may be overlapped to the two opposite longitudinal portions <NUM> of the C-shaped attachment profile <NUM>.

With reference to <FIG>, a central inner region <NUM> of the elastic gasketing portion <NUM> is detached from the outer surface of the topsheet <NUM> to form a pocket open toward the crotch section <NUM>. The central inner region <NUM> of the elastic gasketing portion <NUM> is bordered on three sides by the C-shaped attachment profile <NUM> and is unattached on the edge opposite the transverse outer portion <NUM>.

The absorbent sanitary article <NUM> may comprise a pair of front side panels <NUM> projecting laterally beyond the side edges <NUM> of the front section <NUM>. The front side panels <NUM> may have a surface of loop material (e.g. a non-woven material) for connection with the micro-hook fastening formations <NUM> of the elastic side panels <NUM>.

The absorbent sanitary article <NUM> may comprise a pair of elastic leg cuffs <NUM>. The elastic leg cuffs <NUM> may comprise a plurality of elastic wires which are fixed, e.g. by glue, at discrete points to two opposite non-woven layers. The absorbent sanitary article <NUM> may also comprise leg elastic elements <NUM> which may be formed by stretched elastic wires fixed between the topsheet <NUM> and the backsheet <NUM> and extending along the side edges <NUM> of the chassis <NUM>, which impart a pleated form to the side edges <NUM> in the crotch section <NUM>.

When the absorbent sanitary article is worn, the or each transverse elastic element <NUM> is in contact with the back and/or front waist regions of the user. The elastic side panels <NUM> close the rear and front sections <NUM>, <NUM> of the chassis <NUM> around the user's waist. The outer layer <NUM> of the elastic gasketing portion <NUM> is kept in contact with the user's skin. The outer layer <NUM> of the elastic gasketing portion <NUM> may be formed by a layer of non-woven material to provide a soft feeling against the user's skin.

The central inner region <NUM> of the elastic gasketing portion <NUM> forms an inwardly open pocket between the outer surface of the topsheet <NUM> and the elastic gasketing portion <NUM>. Such pocket helps containing liquid, solid or semi-solid body exudates in the back and/or front waist region. The outer layer <NUM> of the elastic gasketing portion <NUM> facing the topsheet <NUM> may be of impermeable plastic material to form an impermeable barrier which helps containing body exudates in said pocket.

The elastic leg cuffs <NUM> may draw inwardly the inner edge of the elastic gasketing portion <NUM> to distance the inner surface of the elastic gasketing portion <NUM> from the topsheet <NUM>, which has the effect of opening the pocket.

The transverse elastic elements <NUM> of the absorbent sanitary articles <NUM> according to the present invention may be manufactured by an apparatus <NUM> schematically shown in <FIG>.

The apparatus <NUM> comprises a first feeding device <NUM> configured to feed a continuous elastic film <NUM> in a direction parallel to its longitudinal axis.

The apparatus <NUM> comprises a spreader device <NUM> configured to stretch the continuous elastic film <NUM> in a direction transverse to its longitudinal axis. The spreader device <NUM> comprises two discs <NUM> rotatable about respective axes inclined with respect to each other. The discs <NUM> have respective circumferential edges provided with means for gripping respective side edges of the continuous elastic film <NUM>. The discs <NUM> may be provided on their circumferential edges with holes connected to a source of sub-atmospheric pressure for gripping the side edges of the elastic film <NUM> by suction. The circumferential edges of the discs <NUM> may be provided with protruding pins that engage the side edges of the elastic film <NUM> alternatively or in addition to the vacuum gripping means.

The spreader device <NUM> picks up the continuous elastic film <NUM> in a gripping zone with a first width and releases the continuous elastic film <NUM> in an application zone with a second width larger than the first width. In the path from the gripping zone to the application zone the elastic film <NUM> is therefore elastically stretched in a direction transverse to the longitudinal axis.

The apparatus <NUM> comprises a transfer wheel <NUM> having an outer cylindrical surface <NUM> and rotatable about an axis of rotation <NUM>. The transfer wheel <NUM> is provided with gripping elements, e.g. suction holes, configured to hold the transversally stretched continuous elastic film <NUM> on the outer cylindrical surface <NUM>. The spreader device <NUM> applies the transversally stretched continuous elastic film <NUM> on the outer cylindrical surface <NUM> of the transfer wheel <NUM>, where it is held stretched in the transverse direction.

The apparatus <NUM> comprises a longitudinal cutting device <NUM> configured to cut the transversally stretched continuous elastic film <NUM> held on the outer cylindrical surface <NUM> of the transfer wheel <NUM> along two parallel longitudinal cutting lines, to split the continuous elastic film <NUM> in three parallel continuous elastic films <NUM>, <NUM> (<FIG>), which are held in a transversally stretched state on the outer cylindrical surface <NUM> of the transfer wheel <NUM>. The longitudinal cutting device <NUM> may comprise two parallel cutting disks <NUM> rotating about a common axis parallel to the axis of rotation <NUM> of the transfer wheel <NUM>. The cutting disks <NUM> may cooperate with respective circumferential slots formed on the outer cylindrical surface <NUM> of the transfer wheel <NUM>.

After the longitudinal cut of the continuous elastic film <NUM>, the three parallel continuous elastic films <NUM>, <NUM> partially contract in the transverse direction Y, so that the three parallel continuous elastic films <NUM>, <NUM> are spaced apart from each other in the transverse direction Y. The transverse contraction of the three parallel continuous elastic films may be obtained by not providing gripping elements (e.g. suction holes) on portions of the outer cylindrical surface <NUM> of the transfer wheel <NUM> adjacent to the cutting lines, so that lateral portions of the three parallel continuous elastic films adjacent to the cutting lines are not retained on the outer cylindrical surface <NUM> of the transfer wheel <NUM> and contract elastically.

The apparatus <NUM> comprises an anvil wheel <NUM> rotatable about an axis of rotation parallel to the axis of rotation <NUM> of the transfer wheel <NUM>. The anvil wheel <NUM> has an outer cylindrical surface <NUM> provided with holes pneumatically connected to a source of sub-atmospheric pressure. The outer cylindrical surface <NUM> of the anvil wheel <NUM> is tangent to the outer cylindrical surface <NUM> of the transfer wheel <NUM> in a transfer zone <NUM>.

The apparatus <NUM> comprises second and third feeding devices <NUM>, <NUM> configured to feed to the anvil wheel <NUM> first and second continuous non-elastic layers <NUM>, <NUM>, respectively upstream and downstream of the transfer zone <NUM>.

In the transfer zone <NUM> the three parallel continuous elastic films <NUM>, <NUM> are transferred from the transfer wheel <NUM> to the anvil wheel <NUM>. On the anvil wheel <NUM> the three parallel continuous elastic films are sandwiched between the continuous non-elastic layers <NUM>, <NUM> while held transversally stretched.

The apparatus <NUM> comprises a fastening device <NUM> cooperating with the outer cylindrical surface <NUM> of the anvil wheel <NUM>. The fastening device <NUM> may be an ultrasonic welding device, a pressure device for fastening by adhesive, or a thermal or thermomechanical welding device. The fastening device <NUM> joins the transversally stretched three parallel continuous elastic films <NUM>, <NUM> to the continuous non-elastic layers <NUM>, <NUM> to form a continuous elastic laminate <NUM> which is then detached from the anvil wheel <NUM>.

Downstream of the fastening device <NUM> the continuous elastic laminate <NUM> has in a cross section the shape schematically illustrated in <FIG>, comprising three continuous elastic films <NUM>, <NUM> enclosed between two continuous non-elastic layers <NUM>, <NUM>, and anchored to the continuous non-elastic layers <NUM>, <NUM>, e.g. by a pattern of connecting points. The continuous elastic laminate <NUM> has two continuous non-elastic portions <NUM> wherein the elastic films <NUM>, <NUM> are spaced apart from each other and the two continuous non-elastic layers <NUM>, <NUM> are directly fixed to each other. The continuous elastic laminate <NUM> has also non-elastic lateral portions <NUM> where the non-elastic layers <NUM>, <NUM> are directly fixed to each other. Fastening formations <NUM> may be applied on the non-elastic lateral portions <NUM> in longitudinally spaced positions while the continuous elastic laminate <NUM> is held on the anvil wheel <NUM>.

<FIG> schematically shows a machine <NUM> for manufacturing absorbent sanitary products.

The machine <NUM> is configured for forming an array of chassis <NUM>. In the machine <NUM> the array of chassis <NUM> may be formed in the form of a continuous composite tape <NUM> which advances in a machine direction MD, on conveyors <NUM>, <NUM>.

With reference to <FIG>, the continuous elastic laminate <NUM> exiting the apparatus <NUM> of <FIG> may be supplied in-line to the machine <NUM> for manufacturing absorbent sanitary articles.

Alternatively, at the exit of the apparatus <NUM> of <FIG> the continuous elastic laminate <NUM> may be collected in reels which are stored and transported to machines <NUM> for manufacturing absorbent sanitary articles. In this case, the continuous elastic laminate <NUM> which supplies the machine <NUM> is unwound from a reel in an unwinding device (not shown).

With reference to <FIG>, in the machine <NUM> the continuous elastic laminate <NUM>, provided either in-line or unwound from a reel, is transversely stretched in a stretching device <NUM> comprising two disks rotating about respective axes inclined with respect to each other.

The transversely stretched continuous elastic laminate <NUM> is transversely cut in a cutting unit <NUM> to form individual transverse elastic elements <NUM>. The cutting unit <NUM> may be configured to form individual transverse elastic elements <NUM> with a shaped profile as shown in <FIG> and <FIG>. Wastes produced by cutting the transverse elastic elements <NUM> along shaped profiles may be collected by a waste collecting device <NUM>.

At the exit of the cutting unit <NUM> the transverse elastic elements <NUM> are spaced apart from each other in a longitudinal direction by a repitch unit <NUM>.

The repitch unit <NUM> transfers the longitudinally spaced transverse elastic elements <NUM> to a welding unit <NUM> comprising a pair of counter-rotating welding rollers <NUM> forming a gap in which the continuous composite tape <NUM> advances. The welding unit <NUM> applies the individual transverse elastic laminates <NUM> to respective chassis <NUM> in at least one of the rear and front waist sections <NUM>, <NUM>.

A glue dispenser <NUM> may be provided for intermittently dispensing glue layers on the continuous composite tape <NUM> upstream of the welding unit <NUM>.

The individual transverse elastic elements <NUM> are attached to the array of chassis <NUM> such that the elastic gasketing portion <NUM> of each transverse elastic element <NUM> extends between the two side edges <NUM> of the respective chassis <NUM> and the two elastic side panels <NUM> extend transversally outwardly beyond respective side edges <NUM> of the respective chassis <NUM>.

The individual transverse elastic elements <NUM> are attached to the array of chassis <NUM> along respective C-shaped attachment profiles. This attachment may be formed by glue on the transverse outer portions <NUM> and by welding, e.g. ultrasonic welding, on the opposite longitudinal portions <NUM> of the C-shaped attachment profile <NUM>.

Claim 1:
An absorbent sanitary article comprising:
- a chassis (<NUM>) having a longitudinal axis (X), two side edges (<NUM>), rear and front transverse edges (<NUM>, <NUM>), rear and front waist sections (<NUM>, <NUM>), and a crotch section (<NUM>) intermediate between the rear and front waist sections (<NUM>, <NUM>), the chassis (<NUM>) including a topsheet (<NUM>) having an outer surface which in use is in contact with the user's skin, a backsheet (<NUM>), and an absorbent core (<NUM>) set between the topsheet (<NUM>) and the backsheet (<NUM>), and
- at least one transverse elastic element (<NUM>) applied on the outer surface of the topsheet (<NUM>) in at least one of said rear and front waist sections (<NUM>, <NUM>), the at least one transverse elastic element (<NUM>) being elastically stretchable in a transverse direction (Y) orthogonal to said longitudinal axis (X) and comprising in a unitary component an elastic gasketing portion (<NUM>) extending between the two side edges (<NUM>) of the chassis (<NUM>) and two elastic side panels (<NUM>) extending transversally outwardly beyond respective side edges (<NUM>) of the chassis (<NUM>),
wherein the at least one transverse elastic element (<NUM>) is attached to the chassis (<NUM>) along a C-shaped attachment profile (<NUM>) including two opposite longitudinal portions (<NUM>) adjacent to respective side edges (<NUM>) of the chassis (<NUM>) and a transverse outer portion (<NUM>) adjacent to one of said rear and front transverse edges (<NUM>, <NUM>) of the chassis (<NUM>), wherein a central inner region (<NUM>) of the elastic gasketing portion (<NUM>) is detached from the outer surface of the topsheet (<NUM>) to form a pocket open toward said crotch section (<NUM>).