IT202000017686A1 - SYSTEM FOR THE PRODUCTION OF ABSORBENT DIAPERS WITH CHANNELS. - Google Patents

Description

DESCRIPTION

accompanying a patent application for an industrial invention entitled:

?SYSTEM FOR THE PRODUCTION OF ABSORBENT DIAPERS WITH CHANNELS?.

DESCRIPTION TEXT

The present invention relates to a system for producing absorbent diapers with channels.

EP2717823 discloses an absorbent diaper comprising an absorbent layer made of superabsorbent polymeric material (SAP) immobilized on a carrier sheet by a thermoplastic fibrous adhesive material. In the absorbent layer, longitudinal channels are provided which extend along the length direction of the absorbent diaper.

The fact of using an absorbent layer made exclusively of SAP requires the use of thermoplastic fibrous adhesive material. The use of only SAP causes tactile defects of the absorbent diaper, making it more? stiff and grainy to the touch.

Furthermore, the provision of only longitudinal channels limits the capabilities? of absorption of the absorbent layer, not making adequate use of the volume of the absorbent layer.

Purpose of the present invention? to eliminate the drawbacks of the known art, providing a system for the production of absorbent diapers with channels which is simple, rapid, efficient and reliable.

Other purpose? that of providing an absorbent diaper made with this system which has high absorbent characteristics and at the same time is reliable, economical and simple to produce.

These aims are achieved in accordance with the invention with the characteristics of the independent claims.

Advantageous embodiments of the invention appear from the dependent claims.

Additional characteristics of the invention will appear more? clear from the detailed description that follows, referring to a purely exemplifying and therefore non-limiting embodiment thereof, illustrated in the accompanying drawings, in which:

Fig. 1 ? a plan view showing an exploded view of the absorbent diaper obtained with the system according to the invention;

Fig. 2 ? a plan view illustrating an application of glue to a bottom sheet;

Fig. 3 ? a plan view illustrating an application of a core to the bottom sheet;

Fig. 4 ? a plan view illustrating an application of glue to the core;

Fig. 5 ? a plan view illustrating an application of glue to a peripheral portion of a topsheet;

Fig. 6 ? a plan view illustrating an application of two strips of glue to the topsheet intended to correspond with longitudinal channels of the core;

Fig. 7 ? a plan view illustrating a finished absorbent diaper;

Fig. 8 ? a schematic cross-sectional view, taken along the VIII-VIII sectional plane of Fig. 7;

Fig. 9 ? a side view showing a machine for making absorbent diapers according to the invention;

Fig. 10 ? a schematic view illustrating a step of applying glue to the bottom sheet;

Fig. 11 ? a schematic perspective view of a portion of the forming drum of the machine of Fig. 9;

Fig. 12 ? a schematic view illustrating a step of applying glue to the core of the diaper;

Fig. 13 ? a schematic view illustrating a step of applying glue to the topsheet;

Fig. 14 ? a perspective view showing a nip roller for gluing the bottom sheet to the top sheet within the core channels and on the core perimeter;

Fig. 15 ? a top plan view of the absorbent diaper on a conveyor belt from the machine of Fig. 9.

The system for manufacturing absorbent nappies according to the invention is described with the aid of the figures.

For now, with reference to Fig. 1, an absorbent diaper (1) comprising a bottom sheet (2), a top sheet (3) and a core (4) sandwiched between the bottom sheet (2) and a core (4) is illustrated in an exploded view. the top sheet (3).

The bottom and top sheets (2, 3) are made of synthetic nonwoven, for example NW SMS 8-10gsm. Each sheet (2, 3) has a thickness of a few microns.

The nucleus (4) ? made of an absorbent material (M) consisting of a mixture of cellulose fibers (FLUFF) and super absorbent material (SAP). Cellulose fibers are suitably defibrated from a cellulose sheet entering a mill. The quantity? of super absorbent material pu? vary in a ragne from 30 to 80% in weight percentage with respect to the total weight of the nucleus (2).

The core (4) has a substantially rectangular shape in plan view, with a longitudinal dimension extending along the length of the core and a transverse dimension extending along the width of the core. The core (4) has a thickness of about 2.5 and 20 mm.

The core (4) has two longitudinal channels (40) which extend throughout the thickness of the core. The longitudinal channels (40) are arranged on either side of a longitudinal centerline (X). Each longitudinal channel (40) ? equidistant between the longitudinal centerline (X) and a respective lateral edge of the core.

Each longitudinal channel (40) has a length equal to 30-80% of the length of the core. In the figure, the longitudinal channels (40) are arranged in the middle? with respect to a transverse centerline (Y); but the longitudinal channels (40) can be arranged decentralized with respect to the transversal centerline (Y).

The core (2) has a transverse channel (43) disposed in the forward portion (42) of the core between one end? front of the longitudinal channels (40) and an anterior edge of the core. The transverse channel (43) extends throughout the thickness of the core. The transverse channel (43) has a length equal to 20-80% of the width of the anterior portion (42) of the nucleus. The transversal channel (43) ? half willing with respect to the longitudinal center line (X).

Each channel (40, 43) of the nucleus has a depth? equal to the thickness of the nucleus and a width of 5-15 mm. The cross channel (43) improves the capacity? of absorption of the core (4) with respect to the case in which the core (4) has only longitudinal channels.

With reference to Fig. 2, a first type of glue (P1) ? applied to the bottom sheet (2) to fix the core (4) to the bottom sheet (2). The first type of glue (P1) can? be a polyolefin glue.

Advantageously, the glue (P1) is not applied in the areas of the lower sheet (2) intended to be arranged in correspondence with the longitudinal channels (40) of the core, to avoid that subsequently, during the process of forming the longitudinal channels (40) of the core, these areas of the lower sheet (2) can be contaminated with the absorbent material (M). In this case, three longitudinal strips of glue (P1) are applied to the lower sheet (2): an intermediate strip (20) and two lateral strips (21), with the aim of leaving the area of the lower sheet ( 2) destined to be in correspondence with the longitudinal channels of the nucleus. Therefore the distance between the intermediate strip (20) and the side strips (21) ? greater than the width of a longitudinal channel (40) of the nucleus.

Referring to Fig. 3 , the core (4) is formed on the bottom sheet (2), as it will be? explained later. The channels (40) of the core are arranged in correspondence with the areas of the lower sheet (2) where there is no glue (P1).

With reference to Fig. 4, a second type of glue (P2) ? applied on the nucleus (4) to preserve l?integrit? of the structure of the absorbent material (M) of the core. The second type of glue (P2) ? a polyolefin glue.

The glue (P2) ? applied, you will uniform throughout the core (4), by means of a strip (45) having a width substantially equal to the width of the core (4).

This glue (P2) does not have the function of fixing the core (4) to the lower sheet, but only the function of keeping the core (4) intact, preventing it from falling apart. In fact the nucleus 84) ? fixed to the bottom sheet (2) using glue (P1).

With reference to Fig. 5, a third type of glue (P3) ? applied on the upper sheet (3) to peripherally fix the upper sheet to the lower sheet (2) so as to close the core (4) between the lower sheet (2) and the upper sheet (3). The third type of glue (P3) can? be a polyolefin glue.

The glue (P3) ? applied peripherally on the upper sheet (3) so as to form a rectangular frame which surrounds a central area in which the core (4) is to be placed. For this purpose, two longitudinal strips (30) and two transverse strips (31) of glue (P3) are applied on the upper sheet (3), close to edges of the upper sheet (3).

With reference to Fig. 6, a fourth type of glue (P4) ? applied on the upper sheet (3) to fix the upper sheet to the lower sheet (2) in correspondence with the channels (40) of the core. The fourth type of glue (P2) ? a polyolefin glue.

For this purpose, two longitudinal strips (32) of glue (P4) are applied to areas of the upper sheet (3), intended to be arranged in correspondence with the longitudinal channels (40) of the core.

At this point the upper sheet (3) is coupled above the lower sheet (2) so as to close the core between the lower and upper sheet. In this way, as shown in Figs.

7 and 8, an absorbent diaper (1) is obtained. It should be noted that the third type of glue (P3) peripherally fixes the upper sheet to the lower sheet; instead the fourth type of glue (P4) fixes the upper sheet to the lower sheet within the longitudinal channels (40) of the core.

With reference to Fig. 9, a machine (100) for producing the absorbent diaper (1) is illustrated.

In the machine (100) are fed:

- a first sheet material (W1) for making the bottom sheet (2),

- a second sheet material (W2) for making the upper sheet (3), e

- an absorbent material (M) made up of a mixture of cellulose fibers and SAP granules.

With reference to Fig. 10, the lower sheet (2) ? fed towards a first gluing station (A) which is responsible for applying the glue strips (P1) on the lower sheet.

So the bottom sheet (2) with glue (P1) ? fed towards a forming drum (5).

With reference to Fig. 11, the forming drum (5) comprises a perforated cylindrical wall (56) subjected to suction, so as to suck air from the holes in the cylindrical wall (56) towards the inside of the drum and cause adhesion of the bottom sheet (2) on the perforated cylindrical wall (56).

Arranged on the perforated cylindrical wall (56) of the drum are a series of plate-shaped masks (55) with a substantially rectangular opening which delimits a recessed seat conforming to the geometry of the core (4) to be obtained.

On the perforated cylindrical wall (56) of the drum, inside each mask (55), there are inserts (50 and 53) which close the suction holes of the perforated cylindrical wall (56) in correspondence with the channels (40, 43) that are to be realized in the nucleus.

The lower sheet (2) is placed on the cylindrical wall (56) of the forming drum with the glue strips (P1) facing outwards.

The absorbent material (M) ? fed into a hopper (59) to the drum (5). An aspiration system (57) draws air from the holes in the cylindrical wall (56) of the drum towards the inside of the drum (5). Given that the lower sheet (2) ? made of transpiring material, the absorbent material (M) is sucked up and placed on the lower sheet (2) inside the recessed seat delimited by the mask (55) of the forming drum which acts as a mold to obtain the core (4) with the channels longitudinal channels (40) and the transversal channel (43) at the inserts (50, 53).

The bottom sheet (2) and core (4) assembly is vacuum conveyed in a forming channel (58) which surrounds a portion of the drum (5).

At the exit of the training channel (58) ? arranged a second gluing station (B) which is in charge of applying the glue (P2) on the core (4) arranged on the lower sheet (2) arranged on the forming drum (5). Fig. 12 illustrates the application of glue (P2) on the core (4) which serves to maintain the integrity of the nucleus.

With reference to Fig. 13, the upper sheet (3) ? fed towards a third gluing station (C) which is responsible for applying the glue (P3) close to a perimeter edge of the top sheet.

The top sheet (3) with glue (P3) ? fed towards a fourth gluing station (D) which is responsible for applying the two longitudinal strips of glue (P4) on the top sheet.

Going back to Fig. 9, the upper sheet (3) coming out of the fourth gluing station (D) is fed towards the forming drum (5), downstream of the second gluing station (B), so as to couple with the sheet bottom sheet (2) and sandwich the core (4) between the top sheet and bottom sheet. The two longitudinal glue strips (P4) of the upper sheet are arranged exactly in correspondence with the channels (40) of the core.

The group comprising the core (4) disposed between the lower and upper sheets (2, 3) travels on the forming drum (5) and is transferred to a pressing station (E) comprising a counter-roller (6) and a pressure (7)

As shown in Fig. 14 , the pressure roller (7) has a cylindrical body (70) with a jacket (71) having two longitudinal ribs (72) with dimensions and arrangement corresponding to the longitudinal channels (40) of the core. As a result, the longitudinal ribs (72) push the bottom sheet (2) into the channels (40) of the core, so that the bottom sheet (2) contacts the longitudinal glue strips (P4) deposited on the top sheet (3) in correspondence with the longitudinal channels of the core, firmly fixing the lower sheet to the upper sheet, also in a central area, and in this way avoiding that the two sheets detach during use.

At this point, the group comprising the core (4) disposed between the lower and upper sheets (2, 3) ? fed towards a cutting station (8) which is responsible for carrying out a transversal cut of the group so as to obtain absorbent nappies (1) which are fed on a conveyor belt (9) towards an outlet of the machine (100).

Fig. 15 illustrates an absorbent diaper (1) on the conveyor belt (9).

To the present embodiment of the invention, equivalent variations and modifications can be made, within the reach of a person skilled in the art, which in any case fall within the scope of the invention expressed by the appended claims.

Claims (1)

1. Machine (100) for producing an absorbent diaper (1) comprising a core (4) of absorbent material (M) disposed between a bottom sheet (2) and an upper sheet (3), wherein the core ( 4) has longitudinal channels (40) and at least one transverse channel (43), said machine (100) comprising: - a first gluing station (A) which is responsible for applying longitudinal strips of a first glue (P1) on a lower sheet (2) in areas intended not to be in correspondence with the longitudinal channels (40) of the core, - a forming station (F) in which the absorbent material (M) is disposed on said bottom sheet and shaped so as to form said core (4) with longitudinal channels (40) and at least one transversal channel (43), - a second gluing station (B) which is responsible for applying a second glue (P2) on the core (4) arranged on the lower sheet (2), - a third gluing station (C) which is responsible for applying a third glue (P3) close to a perimeter edge of a top sheet (3), - a fourth gluing station (D) which is responsible for applying longitudinal strips of a fourth glue (P4) on the upper sheet (3) intended to be arranged in correspondence with the longitudinal channels (40) of the core, and - a pressing station (E) to press the upper sheet (3) onto the lower sheet (2), so that the upper sheet adheres to the lower sheet along a perimeter where c?? the third glue (P3) and along the longitudinal channels (40) of the core in which c?? the fourth glue (P4). 2. Machine (100) according to claim 1, wherein said forming station (F) comprises: - a forming drum (5) having a cylindrical wall (56) on which said lower sheet (2) is placed, with the first glue (P1) facing outwards, - a feed system which feeds the absorbent material (M) onto said bottom sheet (2) arranged on said forming drum, 3. Machine (100) according to claim 2, wherein said forming drum (5) comprises masks (55) arranged on the cylindrical wall (56) which delimit a recessed seat conforming to the geometry of the core (4) to be obtained and inserts (50, 53) arranged on the cylindrical wall (56) of the drum, inside each mask (55), in correspondence with the channels (40, 43) to be made in the core; 4. Machine (100) according to claim 2 or 3, wherein said cylindrical wall (56) of the forming cylinder ? perforated and said absorbent material feed system comprises a hopper (59) which feeds the absorbent material (M) towards the drum (5) and an aspiration system (57) which sucks air from the holes in the cylindrical wall (56) of the drum towards the inside of the drum (5). 6. Machine (100) according to any one of the preceding claims, wherein said pressing station (E) comprising a counter-roller (6) and a pressure roller (7). 7. Machine (100) according to claim 6, wherein the pressure roller (7) has a cylindrical body (70) with a jacket (71) having two longitudinal ribs (72) of dimensions and arrangement corresponding to the longitudinal channels (40) of the core to enter the longitudinal channels of the core so that the lower sheet (2) comes into contact with the longitudinal glue strips (P4) deposited on the upper sheet (3) in correspondence with the longitudinal channels of the core. 8. Process for producing an absorbent diaper (1) which comprises a core (4) of absorbent material (M) disposed between a bottom sheet (2) and an upper sheet (3), wherein the core (4) has longitudinal channels (40) and at least one transverse channel (43), said procedure including the following steps: - application of longitudinal strips of a first glue (P1) on a lower sheet (2) in areas intended not to be in correspondence with the longitudinal channels (40) of the core, - arrangement of the absorbent material (M) on said bottom sheet (2) and shaping of the absorbent material so as to form said core (4) with longitudinal channels (40) and at least one transversal channel (43), - application of a second glue (P2) on the core (4) arranged on the lower sheet (2), - application of a third glue (P3) near a perimeter edge of a top sheet (3), - application of longitudinal strips of a fourth glue (P4) on the upper sheet (3) intended to be arranged in correspondence with the longitudinal channels (40) of the core, and - pressing of the upper sheet (3) on the lower sheet (2), so that the upper sheet adheres to the lower sheet along a perimeter where c?? the third glue (P3) and along the longitudinal channels (40) of the core in which c?? the fourth glue (P4).