Method and apparatus for forming channels in an absorbent core with vacuum

Abstract

A method for forming an absorbent core with a channel formed therein includes the steps of positioning a source of fiberized pulp adjacent a permeable surface, applying a vacuum to the permeable surface to draw the fiberized pulp onto the permeable surface to form an absorbent core, positioning the absorbent core adjacent a channel forming surface including a permeable channel forming portion shaped in a predetermined shape of a channel to be formed in the absorbent core, and applying a vacuum source to withdraw fiberized pulp from the absorbent core through the permeable channel forming portion.

Description

International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078METHOD AND APPARATUS FOR FORMING CHANNELS IN AN ABSORBENT CORE WITH VACUUMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 685,786 filed on August 22, 2024, which application is incorporated herein by reference in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] Not applicable.BACKGROUND

[0003] Channels are often used in the absorbent cores of products such as diapers, incontinence products, pet training pads, hospital underpads, feminine hygiene products, and baby wipes, by way of example. These channels are important for a number of reasons. For example, channels enhance absorption by helping to distribute urine or other fluids evenly throughout the absorbent core. This prevents pooling in one area, which can lead to leaks and discomfort. Additionally, by spreading the liquid, channels reduce the likelihood of the absorbent core feeling heavy or sagging in one spot. This contributes to the wearer's comfort, especially for longer periods of wear. Efficient fluid distribution also reduces the chances of leaks because the absorbent material can hold more fluid without becoming saturated in localized areas. Channels can also facilitate quicker absorption by providing pathways for liquid to move into the core material where it can be retained. Effective channeling also allows manufacturers to design thinner products that still offer high absorbency. This makes wearable products such as diapers and feminine hygiene products more discreet and comfortable to wear.

[0004] Because channels in the absorbent core of diapers and similar products can therefore be important for maximizing performance, comfort, and reliability in managing moisture and preventing leaks, processes for forming channels in absorbent cores are known in the art. For example, the methods for forming channels disclosed in WO 2018172902 and EP3403627A1 provide at least one spreader for spreading absorbent material on a forming drum. The forming- 1 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 drum has a suction system that inhibits suction where the channels are to be formed so that the absorbent material is not retained where the channels are formed.

[0005] Creating channels, therefore, adds complexity to the manufacturing process, requiring specialized equipment and techniques. This can increase production costs and require careful calibration to ensure quality. Improper placement or formation of channels (e.g., formed channels not substantially devoid of absorbent material, further, can result in inefficient absorption or uneven liquid distribution, leading to potential leakage.

[0006] Accordingly, there is a need for a system and method for forming consistent channels in absorbent products while minimizing costs. The current disclosure addresses these and other issues.BRIEF SUMMARY

[0007] In an aspect of the invention there is provided an apparatus for forming an absorbent core with a channel formed therein. The apparatus includes at least one vacuum source, a permeable forming surface in communication with the at least one vacuum source, the vacuum source configured to draw absorbent material onto the permeable forming surface to form an absorbent core. A channel forming surface is configured to receive the absorbent core at a location downstream in a machine direction from the permeable forming surface. The channel forming surface includes a permeable channel forming portion shaped in a pre-determined shape corresponding to a channel to be formed in the absorbent core. The permeable channel forming portion is in communication with the at least one vacuum source such that absorbent material is withdrawn from the absorbent core to form a channel of the predetermined shape therein when vacuum is drawn through the permeable channel forming portion.

[0008] According to an embodiment, the permeable forming surface is located on a first rotating drum and the channel forming surface is located on a second rotating drum, downstream of the first rotating drum in the machine direction.

[0009] Alternatively, the channel forming surface is located on a rotating pad, downstream of the permeable forming surface in the machine direction or the channel forming surface is located on a belt of a conveyor, downstream of the permeable forming surface in the machine direction.- 2 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078

[0010] According to an embodiment, the permeable channel forming portion includes an aperture in fluid communication with an interior vacuum chamber of one of a rotating drum and a rotating pad.

[0011] According to an embodiment, the permeable channel forming portion of the channel forming surface is circumscribed by a channel forming ridge extending from the outer surface of the channel forming surface.

[0012] According to an embodiment, the channel forming ridge is made of a compliant material or a rigid material. The outer edges of the channel forming ridge may be radiused or nonradiused.

[0013] The channel forming surface according to any of the embodiments described herein may include a permeable channel forming portion of any suitable size and shape to form at least one channel in an absorbent core. Thus, the size and / or number and / or arrangement of apertures may be determined as a function of the desired channeled absorbent core specifications.

[0014] According to an embodiment, the permeable forming surface is provided on forming drum that rotates in a first direction. A forming chute coupled adjacent an outer surface of the forming drum may be configured to deliver an absorbent material to the surface of the forming drum to form an absorbent core.

[0015] According to an embodiment, a channel forming unit is positioned downstream from a forming drum in a machine direction. An outer surface of the channel forming unit may include a permeable channel forming portion shaped to correspond to a pre-determined shape of at least one channel. The permeable channel forming portion may be in communication with at least one vacuum source such that absorbent material is withdrawn from the absorbent core to form at least one channel in the shape of the permeable channel forming portion of the outer surface of the channel forming unit in the absorbent core when vacuum is drawn through the permeable channel forming portion.

[0016] According to an embodiment, the permeable channel forming portion of the channel forming unit is circumscribed by a channel forming ridge extending from the outer surface of the channel forming unit.- 3 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078

[0017] According to an embodiment, the upwardly extending channel forming ridge is one or more of a rubber, silicone rubber, polyurethane, a thermoplastic polyamide, a thermoplastic polyurethane, a thermoplastic elastomer, and a neoprene foam.

[0018] According to an embodiment, the channel forming ridge has a cross-section that is triangular in shape, with the base of the triangle adjacent the surface of the substrate and an opposing vertex directed away from the substrate. Alternatively, the channel forming has a generally rectangular cross-section.

[0019] According to an embodiment, the apparatus may include a single vacuum source, or multiple vacuum sources, with a first vacuum source in communication with the forming drum and a second vacuum source in communication with the permeable channel forming portion.

[0020] In another aspect of the invention there is provided a channel forming unit for use in a system for forming an absorbent core including a substrate comprising a permeable channel forming portion shaped to correspond to a pre-determined shape of at least one channel to be formed in an absorbent core, and an upwardly extending channel forming ridge circumscribing the permeable channel forming portion, a height of the ridge being selected to correspond to a depth of the at least one channel to be formed in the absorbent core.

[0021] According to an embodiment, the substrate is an outer surface of a rotatable drum having an interior vacuum chamber. Alternatively, the substrate is an outer surface of a vacuum transfer pad or an outer surface of an insert coupleable to a surface of a vacuum transfer pad or a rotatable drum.

[0022] According to an embodiment, the substrate is formed to correspond to a surface of a vacuum transfer pad or a surface of a rotatable drum.

[0023] According to an embodiment, the permeable channel forming portion includes at least one aperture in fluidic communication with an interior vacuum chamber of the channel forming unit and the at least one aperture includes one of a continuous void and an air permeable screen.

[0024] According to an embodiment, the substrate comprises apertures for receiving fasteners to couple the substrate to a surface of a vacuum transfer pad or a surface of a rotatable drum.

[0025] In another aspect of the invention there is provided a method for forming an absorbent core with at least one channel formed therein.

[0026] The method comprises the features recited in the independent method claim.- 4 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078

[0027] The method includes positioning a source of absorbent material adjacent a permeable surface, applying a vacuum to the permeable surface to draw the absorbent material onto the permeable surface to form an absorbent core, positioning the absorbent core adjacent a channel forming surface including a permeable channel forming portion shaped in a predetermined shape of a channel to be formed in the absorbent core, and drawing a vacuum through the permeable channel forming portion to withdraw absorbent material from the absorbent core.

[0028] According to an embodiment, the method includes the step of circumscribing the permeable channel forming portion of the channel forming surface with a channel forming ridge extending from the outer surface of the channel forming surface.

[0029] According to an embodiment, the method includes the step of pulling the withdrawn absorbent material through the permeable channel forming portion and into an interior chamber of one of a channel forming unit having the permeable channel forming portion formed on an outer surface thereof.

[0030] According to an embodiment, the method includes positioning the absorbent core adjacent a vacuum drum having the channel forming surface integrally formed thereon. Alternatively, the method includes positioning the absorbent core adjacent a rotating vacuum transfer pad having the channel forming surface integrally formed on an outer surface thereof.

[0031] A system according to any of the embodiments of the invention may be used to carry out a method according to any of the embodiments of the invention. A method according to any of the embodiments of the invention may be carried out using a system according to any of the embodiments of the invention.

[0032] In a further aspect of the invention there is provided the use of an apparatus according to any of the embodiments described herein, or a method according to any of the embodiments described herein to form an absorbent core with at least one channel formed therein and / or to manufacture an absorbent article, such as a disposable absorbent article including an absorbent core with at least one channel formed therein.

[0033] These and other advantages and features will be more readily understood from the following detailed description of preferred embodiments of the invention that is provided in connection with the accompanying drawings.- 5 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The features, aspects and advantages of the disclosure will become apparent when consideration is given to the following detailed description thereof. Such detailed description makes reference to the following drawings.

[0035] FIG. 1 is a side view of an apparatus for forming an absorbent core assembly with channels, consistent with the disclosure;

[0036] FIG. 2 is a perspective view of a portion of the vacuum channel forming unit of FIG. 1 including a channel forming ridge;

[0037] FIG. 3 is a schematic side view of the vacuum channel forming unit of FIG. 1, illustrating the channel forming ridge of FIG. 3.

[0038] FIG. 4A is a schematic view of the vacuum channel forming unit of FIG. 1, according to one embodiment;

[0039] FIG. 4B is a schematic view of the vacuum channel forming unit of FIG. 1, according to another embodiment;

[0040] FIG. 5 is a schematic illustration the absorbent core assembly formed by FIG. 1 at various stages of production;

[0041] FIG. 6 is a top plan view of the absorbent core assembly formed by the apparatus of FIG. 1;

[0042] FIG. 7 is a schematic representation of a cross-section of an absorbent core assembly formed by the apparatus of FIG. 1, shown along line 6-6 of FIG. 6;

[0043] FIG. 8 is a side view of an apparatus for forming an absorbent core assembly with channels, according to another embodiment;

[0044] FIG. 9 is a top plan view of the absorbent core assembly formed by the apparatus of FIG. 8;

[0045] FIG. 10 is a schematic representation of a cross-section of an absorbent core assembly formed by the apparatus of FIG. 8, shown along line 9-9 of FIG. 9;

[0046] FIG. 11 is a side view of an apparatus for forming an absorbent core assembly with channels, according to another embodiment;

[0047] FIG. 12 is a top plan view of the absorbent core assembly formed by the apparatus of FIG. 11;- 6 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078

[0048] FIG. 13 is a schematic representation of a cross-section of an absorbent core assembly formed by the apparatus of FIG. 11, shown along line 12-12 of FIG. 12;

[0049] FIG. 14 is a side view of an apparatus for forming an absorbent core assembly with channels, according to another embodiment;

[0050] FIG. 15 is a top plan view of the absorbent core assembly formed by the apparatus of FIG. 14;

[0051] FIG. 16 is a schematic representation of a cross-section of an absorbent core assembly formed by the apparatus of FIG. 14, shown along line 15-15 of FIG. 15;

[0052] FIG. 17 is a side view of an apparatus for forming an absorbent core assembly with channels, according to another embodiment;

[0053] FIG. 18 is a side view of an apparatus for forming an absorbent core assembly with channels, according to another embodiment;

[0054] FIG. 19 is a side view of an apparatus for forming an absorbent core assembly with channels, according to another embodiment; and

[0055] FIG. 20 is a top plan view of the vacuum channel forming conveyor of FIG. 19.

[0056] The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals.DETAILED DESCRIPTION

[0057] Referring now to the Figures and more particularly FIG. 1, an apparatus 10 for forming absorbent cores with channels constructed in accordance with the present disclosure is shown. The apparatus 10 comprises a feed unit or forming chute 12 that directs absorbent material such as fiberized pulp or fluff, curly fibers, and / or superabsorbent polymer (SAP) onto a forming drum 14 which includes a permeable (e.g., a screen or perforated) forming surface 13 to form an absorbent core. The forming drum 14 can also, for example, include one or more depressions that define a shape of the absorbent core to be formed. The depression(s) can be shaped to create a continuous absorbent core or multiple, discrete absorbent cores, in which case the surface of the forming drum 14 can include multiple shaped pockets that define the 2D or 3D shape of the discrete cores. A continuous “form-on” web material 15, such as a nonwoven material, tissue web material, or acquisition distribution layer substrate, as non-limiting examples, can be fed onto the forming- 7 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 surface of the forming drum 14 from an input station 17, and the absorbent core can be formed on the web material 15. In some applications the web material 15 may also include an optional adhesive application unit 19 to apply a first adhesive layer or adhesive pattern on the side of the web material 15 facing away from the forming drum 14 using a known technique such as spray coating or slot coating.

[0058] Referring still to FIG. 1 and also to FIG. 3, the forming drum 14 can be mounted to rotate about rotational axis 16, and, as described above, can comprise an outer forming surface 13 that is permeable and which can, for example, be formed of a wire screen, or a substrate that includes apertures or perforations. In an alternative embodiment, forming drum 14 may be replaced with a forming screen of a type known in the art. A vacuum source 18 can be in communication with an interior vacuum chamber of the forming drum 14 to draw the absorbent material onto the outer surface 13 of the forming region or pocket 11 of the forming drum 14 to form an absorbent core. The outer forming surface 13 of the forming drum 14, for example, can rotate into a forming chamber 22 substantially free of absorbent material, and a pressure difference across the outer forming surface 13 of the forming drum 14 can cause absorbent material to accumulate on the outer forming surface 13 of the drum 14 to form an absorbent core. An optional scarfing unit 20 can be provided downstream of the forming chamber 22 to trim excess material from a formed absorbent core.

[0059] Referring still to FIGS. 1 and 3 and also to FIG. 2, the absorbent core formed on the forming drum 14 can be transferred from the forming drum 14 to a conveyor 24 by a channel forming unit 30 located downstream from the forming drum 14 in a machine direction 15. The channel forming unit 30 can include a substrate 56 comprising a permeable channel forming portion 34 shaped to correspond to a pre-determined shape or pattern selected to correspond to one or more channels to be formed in the absorbent core. In one embodiment, the substrate 56 is the outer surface of a rotatable drum 53 configured to rotate about axis 32, in a direction opposite that of forming drum 14. An interior vacuum chamber 37 of the rotatable drum 53 can also be in fluid communication with a vacuum source, which may be vacuum source 18 or a separate vacuum source (not shown) according to alternate embodiments. The permeable channel forming portion 34 can comprise one or more apertures 54 or perforations through which vacuum is drawn in a manner that selectively removes the portion of the absorbent material aligned above the channel- 8 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 forming portion 34 by drawing the absorbent material through the aperture(s) 54 and into the interior vacuum chamber 37 of the channel forming unit 30. The channel forming portion 34 and its corresponding aperture(s) 54 may be configured to form one or more channels in a variety of shapes and sizes, including, as non-limiting examples, a substantially elongate channel that extends along a longitudinal or transverse direction of the absorbent core and has a center line that is straight, curved, or a polyline, one or more channels defining voids in the shape of dots or other discrete shapes that may optionally be arranged in a pattern to define an overall graphic design on the absorbent core, a substantially U-shaped, V-shaped, Y-shaped, or X-shaped channel, or a channel forming one or more substantially enclosed regions of absorbent material - for example a substantially “O” shaped region, a rectangular region, or “8” shaped region. The channel forming portion 34 can be formed in a number of different substrates, including a substrate that comprises an outer surface of a drum, an outer surface of a belt of a conveyor, or an outer surface of a vacuum transfer pad, or on a separate substrate that can be coupled to a rotatable drum, conveyor, or vacuum transfer pad. The substrate can, for example, comprise a rigid material that is shaped to correspond to an underlying drum, a belt of a conveyor, or vacuum transfer pad, or comprise a compliant material that can be formed to the underlying surface, and can be coupled or adhered to the underlying surface using fasteners such as threaded fasteners, rivets, glues, adhesives, or other coupling devices.

[0060] The channel forming unit 30 is described above as drawing the absorbent material through apertures 54 and into the interior vacuum chamber 37 of the channel forming unit 30. Apertures 54 may be continuous voids or include an air permeable screen or mesh material with openings sized to be substantially impermeable to the absorbent material. In such cases, the absorbent material corresponding to the desired channel locations is drawn away from the absorbent core and held against the screened surface of the channel forming portion 34 by the applied vacuum. Continued rotation of the channel forming unit 30 away from the absorbent core may bring the screened surface proximate an optional removal system 43 that removes any absorbent material present on the screened surface. According to alternative embodiments, the removal system 43 may include a blowing system comprising an air jet, fan, impeller, or other known means to force air against the screened surface in such a way as to blow away any absorbent material on the screened surface, brushes and / or a scraper acting against the screened surface,- 9 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 and / or a suction system for extracting the absorbent material from the screened surface before rotation of the channel forming unit 30 brings the channel forming portion 34 into proximity with a new section of absorbent material to remove. In exemplary embodiments, the removal system 43 may be in communication with optional duct 31 and / or may be located in a common housing and absorbent material return loop as the scarfing unit 20.

[0061] With continued reference to FIGS. 1- 3, each permeable channel forming portion 34 of the outer surface 56 of the drum 53 can be circumscribed by an optional channel forming ridge 36 extending from the outer surface 56 of the channel forming unit 30 toward the outer surface of the forming drum 14. The channel forming ridge 36 can be made of a compliant material such as rubber, silicone rubber, polyurethane, a thermoplastic polyamide (TPA), a thermoplastic polyurethane (TPU), a thermoplastic elastomer (TPE), or neoprene foam, as nonlimiting examples, that permits the channel forming ridge 36 to depress inward toward the outer surface 56 of the drum 53 when pressure is applied thereto, such as when a compressive force is applied thereto as the channel forming ridge 36 presses into the absorbent core 60 and against the outer surface 13 of the forming drum 14. The channel forming ridge 36 returns to its original configuration when the compressive force is removed, such as after the channel forming ridge 36 rotates out of contact with the absorbent core 60. Alternatively, the channel forming ridge 36 may be made of a rigid material. Optionally, the outer edges of the channel forming ridge 36 may be radiused. As illustrated here, the channel forming ridge 36 can have a cross-section that is triangular in shape, with the base of the triangle adjacent the surface of the channel forming unit 30 and an opposing vertex directed at the absorbent core 60. In other embodiments the channel forming ridge 36 may have a generally rectangular cross-section. As illustrated here, there are two parallel channel forming ridges 36 corresponding to two permeable channel forming portions 34 for forming two channels in the absorbent core 60. A height 51 of the channel forming ridge 36 is selected to correspond to a desired depth of the at least one channel to be formed in the absorbent core. According to various embodiments, the height 51 may be selected to be substantially equal to the depth 55 of the pocket 11 or the thickness 57 of the absorbent core. As used herein, substantially equal means the height 51 differs from the depth 55 of the pocket 11 or the thickness 57 of the absorbent core 60 by less than 15%, alternatively less than 10%, alternatively less than 5%,- 10 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 alternatively less than 2%, alternatively less than 1%, or alternatively that the height 51 and depth 55 or thickness 57 are equal.

[0062] Optionally, the channel forming portion(s) 34 may be provided on a substrate comprising a channeled insert 41 that includes apertures for receiving fasteners that enable the plate 41 to be removably coupled to the outer surface 56 of the channel forming unit 30. In such an embodiment, one channeled insert 41 may be easily exchanged for another channeled insert (not shown) having a different configuration of channel forming portions 34 for use in manufacturing different product configurations or with a non-channeled insert (not shown) - i.e., a blank - for use in manufacturing product configurations where the absorbent core does not include any channels. The spacing shown in FIG. 3 is for illustrative purposes only to show the different components.

[0063] In one embodiment, shown in FIG. 4A, channel forming unit 30 includes a main drum body 700 that rotates about axis 32. One or more permeable channel forming portions 34, each including one or more optional channel forming ridges 36, is located at spaced intervals on an outer cylindrical surface 702 of the drum body 700.

[0064] In an alternative embodiment, shown in FIG. 4B, channel forming unit 30 includes one or more rotating vacuum transfer pucks or pads 704, each of which rotates about an axis 32 via a respective shaft 706. One or more permeable channel forming portions 34, each including one or more optional channel forming ridges 36, is located on an outer surface 708 of each vacuum transfer pad 704. The rotational speed of each vacuum transfer pad 704 may be varied along its travel path via any known electrical, magnetic, or mechanical drive system (not shown), such as servo drives, electro-magnetic movers, mechanical cams, or combinations thereof coupled to respective shafts 706 via a linkage, gearing, or other known means. As a result, the pitch at which the channel forming portions 34 contact the absorbent core can be varied, such that the same channel forming unit 30 with vacuum transfer pads 704 can be used to form channels at varied pitches as desired for various product sizes.

[0065] Referring still to FIG. 1 , a continuous top or cover web material 26, such as a nonwoven material, a tissue material, or an acquisition distribution layer substrate, as non-limiting examples, can be fed from an input station 27 and placed onto the absorbent core at combining roll 33. In some applications an optional adhesive application unit 29 is provided to apply an optional second- 11 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 adhesive layer or adhesive pattern on the side of the cover web material 26 facing the absorbent core. A controller (not shown), such as a programmable logic controller, computer, or similar system, that includes, by way of example, a microprocessor, memory components, communication devices and / or user input devices, can be in communication with various stages of the system and the corresponding vacuum source(s) to control the process, and to selectively effect movement of the absorbent core through the system, and activation and deactivation of vacuum source(s).

[0066] Still referring to FIG. 1, after exiting the channel forming unit 30, the intermediate absorbent core assembly is transported along the conveyor 24 in a machine direction 25 to a folding unit 28, which may be a folding board, plate, rods, rollers, plow, air curtain, or other known folding technology. The folding unit 28 folds the longitudinally extending edges of the form-on web material 15 over and around the side edges of the absorbent core and onto the upward-facing surface of the absorbent core.

[0067] Thereafter, the intermediate absorbent core assembly may pass through an optional channel bonding unit 39. The channel bonding unit 39 is depicted in FIG. 1 as an ultrasonic bonding unit including an anvil 36 and horn 38 that cooperate to ultrasonically bond facing layers of the web material 15 within the formed channels. In other embodiments, the channel bonding unit 39 may include components that bond the facing layers of the web at one or more bond points within channels via different mechanical bonding techniques such as, for example, thermal, pressure, or adhesive bonding techniques or various other forms of bonding known in the industry, or combinations of the same. Thereafter, the intermediate absorbent core assembly may pass through an optional debulking station 40, which includes a cylindrical rotating anvil roll 42 and a debulking roll 44, and / or an optional embossing station 46, which includes a cylindrical rotating anvil roll 48 and embossing roll 50. The absorbent core is at least partially compressed as it passes through the nip formed between the debulking roll 44 and its corresponding anvil roll 42, thereby increasing its density and structural integrity. The embossing station 46 imparts an embossed pattern in the partially formed core assembly. In some embodiments, vacuum may be drawn through holes in one or both of the anvil rolls 42, 46 to hold the partially formed core assembly in position as it passes through the debulking and embossing stages. In other embodiments, anvil rollers 42, 46 may operate without vacuum. One skilled in the art will recognize that the arrangement of channel bonding unit 39, debulking station 40, and embossing station 46 in the- 12 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 machine direction 25 may be varied depending on process parameters and desired product characteristics, with any of the units 39, 40, and 46 being located first, between, or last relative to one another in the machine direction 25.

[0068] Thereafter, the intermediate absorbent core assembly may pass through an optional cutting unit 52, such as a rotary knife unit or other known technology, to form discrete absorbent core assemblies, which are subsequently moved to one or more additional downstream processing units (not shown) for completion of the disposable product in which the discrete absorbent core assemblies may be encapsulated between a back sheet formed of an impermeable material and at least one hydrophilic top sheet. Other layers may be provided in the final disposable product in manners known in the art.

[0069] Referring now to FIG. 5 with continued reference to FIGS. 1-3, figures of intermediate absorbent core assemblies 65, 67, 69, 71, and 73 in various stages of production are shown. Adhesive application unit 19 may apply a first adhesive layer 58 to the form-on web material 15, yielding intermediate absorbent core assembly 65. The vacuum source 18 coupled to the forming drum 14 causes absorbent material from the forming chute 12 to be drawn onto the forming drum 14 to form an intermediate absorbent core assembly 67 including an absorbent core 60, which may be a continuous core or comprise individual core components. As the intermediate absorbent core assembly 67 rotates in the direction of the channel forming unit 30, the absorbent core 60 formed on substrate 15 is received between the rotating surfaces of the channel forming unit 30 and forming drum 14, as shown in FIG. 3. The interior vacuum chamber 37 of the channel forming unit 30 is in communication with a vacuum source, which may be vacuum source 18 or a second vacuum source (not shown), which causes absorbent material aligned with the channel forming portion 34 and corresponding channel forming ridge 36 to be drawn from the surface of the absorbent core 60 and into the channel forming unit 30 through the apertures 54 of the permeable channel forming portion 34 yielding intermediate absorbent core assembly 69. The absorbent material pulled from the absorbent core 60 can be directed out of the drum 30 through a tube 66 for collection or disposal. The tube 66 can be coupled to an optional duct 31 to re-direct the removed material to a fiberizer (not shown), to the forming chute 12, or to the forming chamber 22, where the recycled absorbent material is incorporated with virgin absorbent material. The channel forming ridge 36 aids in focusing the vacuum at the portion of the absorbent core 60 where- 13 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 the channel is to be formed, producing a channeled absorbent core 49 with one or more channels 47 formed therein.

[0070] Subsequently a cover web 26 can be adhered onto the outer surface to form wrapped intermediate absorbent core assembly 71. The channels 47 may be sealed via channel bonds 64 that attach the form-on web 15 to the cover web 26. Channel bonds 64 may be formed by any means as known in the art, for example, via adhesive or adhesives and / or mechanical bonding means such as thermo-sealing, pressure bonding, or ultrasonic bonding, yielding intermediate absorbent core assembly 73.

[0071] A top plan view of the intermediate absorbent core assembly 73 formed by the apparatus 10 is shown in FIG. 6 before it is cut into discrete inserts by the optional cutting unit 52. With reference to FIG. 6 and the corresponding cross-sectional view thereof shown in FIG. 7, the intermediate absorbent core assembly 73 includes the form-on web 15, the first adhesive layer 58, channeled absorbent core 49, the optional second adhesive layer 62, and the cover web 26. The first adhesive layer 58 is provided between the form-on web 15 and the absorbent core 60. Longitudinally extending edge portions 106, 108 of the form-on web 15 are folded around side edges of the channeled absorbent core 49 and folded over sections 110, 112 abut against a second surface of the channeled absorbent core 49. The second adhesive layer 62 is between the cover web 26 and the channeled absorbent core 49, and is between the cover web 26 and the folded over sections 110, 112 of the longitudinally extending edge portions 106, 108. The channel(s) 47 extend through all or substantially all of the thickness of the channeled absorbent core 49. The form-on web 15 and cover web 26 are coupled together at the location of the channel(s) 47 via channel bonds 64. The spacing shown in FIG. 7 is for illustrative purposes only to show the different layers.

[0072] FIG. 8 depicts an alternative embodiment of an apparatus 200 for manufacturing an intermediate absorbent core assembly 202, as shown in FIGS. 8 and 9. Apparatus 200 differs from that of FIG. 1 in that the cover web 26 is fed in upstream of the folding unit 28 and an additional adhesive application unit 204 is provided to apply a third adhesive layer 206, yielding the intermediate absorbent core assembly 202 shown in FIGS. 8 and 9 wherein the extending edge portions 106, 108 of the form-on web 15 are folded around side edges of the channeled absorbent core 49 and folded over sections 110, 112 are proximate to a second surface of the channeled absorbent core 49 and proximate to a second surface of the cover web 26. The channel(s) 47 extend- 14 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 through all or substantially all of the thickness of the channeled absorbent core 49. The form-on web 15 and cover web 26 are coupled together at the location of the channel(s) 47 via channel bonds 64. The spacing shown in FIG. 10 is for illustrative purposes only to show the different layers. Other aspects of this embodiment are similar to that shown in FIGS. 1, 5, and 6 and thus labeled with similar part numbers.

[0073] FIG. 11 depicts an alternative embodiment of an apparatus 300 for manufacturing an intermediate absorbent core assembly 302, shown in FIGS. 11 and 12. Apparatus 300 differs from apparatus 10 of FIG. 1 in that the folding unit 28 of FIG. 1 is omitted, yielding the intermediate absorbent core assembly 302 shown in FIGS. 11 and 12 wherein the longitudinally extending edge portions 106, 108 of the form-on web 15 are coupled to the longitudinally extending edge portions 304, 306 of the cover web 26 via adhesive layer 58 (as shown), or via adhesive layer 62 in an alternative embodiment. The channel(s) 47 extend through all or substantially all of the thickness of the channeled absorbent core 49. The form-on web 15 and cover web 26 are coupled together at the location of the channel(s) 47 via channel bonds 64. The spacing shown in FIG. 13 is for illustrative purposes only to show the different layers. Other aspects of this embodiment are similar to that shown in FIGS. 1, 5, and 6 and thus labeled with similar part numbers.

[0074] FIG. 14 depicts an alternative embodiment of an apparatus 400 for manufacturing an intermediate absorbent core assembly 402, shown in FIGS. 14 and 15. Apparatus 400 differs from apparatus 10 of FIG. 1 in that the input station 27 of FIG. 1 for cover web 26 is omitted. The intermediate absorbent core assembly including form-on web 15, adhesive layer 58, and channeled absorbent core 49 exits the channel forming unit 30 and translates along the conveyor 24 to folding unit 28, which folds the first longitudinally extending edge portion 403 over onto the channeled absorbent core 49 to form a first folded over section 404. The partially folded assembly then translates along the conveyor 24 to another adhesive application station 405 at which adhesive 406 is applied to an end portion of the first surface of the first folded over section 404. A second folding unit 408, which may be a folding board, plate, rods, rollers, plow, air curtain or other known folding technologies then folds a second longitudinally extending edge portion 410 over onto the channeled absorbent core 49 and onto the adhesive 406 on the end portion of the first folded over section 404 to form a second folded over section 412. The channel(s) 47 extend through all or substantially all of the thickness of the channeled absorbent core 49. Channel bonds 64 couple- 15 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 together facing surfaces of the form-on web 15 at the location of the channel(s) 47. The spacing shown in FIG. 16 is for illustrative purposes only to show the different layers. Other aspects of this embodiment are similar to that shown in FIGS. 1, 5, and 6 and thus labeled with similar part numbers.

[0075] FIG. 17 depicts an alternative embodiment of an apparatus 500 for manufacturing the intermediate absorbent core assembly 402, shown in FIGS. 14 and 15. Apparatus 500 differs from apparatus 400 of FIG. 14 in that absorbent material is fed directly onto the outer forming surface 13 of the forming drum 14. The vacuum of the forming drum 14 is drawn through holes in the outer forming surface 13 and holds the absorbent material against the forming drum 14. The absorbent material exits the forming drum 14 onto channel forming unit 30, which forms channels 47 within the absorbent material via permeable channel forming portion 34 in the manner described above. Adhesive application station 29 is provided between the input station 27 and the channel forming unit 30 and applies adhesive layer 58 to a first surface of cover web material 26 to which the channeled absorbent core 49 is bonded. Downstream, a first folding unit 28 that folds the first longitudinally extending edge portion 403 over onto the channeled absorbent core 49 to form the first folded over section 404. The partially folded absorbent assembly then translates along the conveyor 24 to adhesive application station 405 at which adhesive 406 is applied to an end portion of the first surface of the first folded over section 404. The second folding unit 408 then folds the second longitudinally extending edge portion 410 over onto the channeled absorbent core 49 and onto the adhesive 406 on the end portion of the first folded over section 404 to form the second folded over section 412. Other aspects of this embodiment are similar to that shown in FIGS. 1, 5, and 6 and thus labeled with similar part numbers.

[0076] FIG. 18 depicts an alternative embodiment of an apparatus 600 for manufacturing the intermediate absorbent core assembly 73 of FIGS. 5 and 6. Apparatus 600 differs from apparatus 100 of FIG. 1 in that the channel forming unit 30 is shifted downstream and a traditional transfer roller 602 having a generally smooth outer cylindrical surface is positioned adjacent forming drum 14. The intermediate absorbent core assembly exits the forming drum 14 and is transferred via transfer roller 602 onto the conveyor 24, which then transports the intermediate absorbent core assembly toward the channel forming unit 30. The permeable channel forming portion 34 of the channel forming unit 30 then acts against the surface of the conveyor 24 to form channels 47. Other- 16 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 aspects of this embodiment are similar to that shown in FIGS. 1, 5, and 6 and thus labeled with similar part numbers. It is contemplated that apparatus 200 (FIG. 8), apparatus 300 (FIG. 11), apparatus 400 (FIG. 14), and apparatus 500 (FIG. 17) could be similarly modified by adding a transfer roller 602 and shifting the channel forming unit 30 to a location downstream of the newly added transfer roller 602 and upstream of folding unit 28 in the machine direction 25.

[0077] Referring now to FIGS. 18, 19 and 20, an alternative apparatus 800 for manufacturing the intermediate absorbent core assembly 73 is shown that includes a channel forming conveyor 802 in place of the channel forming unit 30 of apparatus 600 (FIG. 18). Channel forming conveyor 802 is positioned adjacent conveyor 24. In operation, intermediate absorbent core assembly exits the forming drum 14 and is transferred via transfer roller 602 onto the conveyor 24. As the intermediate absorbent core assembly travels along conveyor 24, the exposed surface of the absorbent core is exposed to a permeable channel forming portion 804 formed within the belt 806 of channel forming conveyor 802. The permeable channel forming portion 804 can comprise one or more apertures or perforations 808 formed within the belt 806. A vacuum source (e g., vacuum source 18 or a separate vacuum source (not shown)) that is communication with an interior vacuum chamber 807 of the channel forming conveyor 802 can apply pressure to the absorbent core in a manner that selectively removes the portion of the absorbent material aligned above the channel forming portion 804 by drawing the absorbent material through the aperture(s) 808 and into the interior of the channel forming conveyor 802. Other aspects of this embodiment are similar to that shown in FIGS. 1, 5, and 6 and thus labeled with similar part numbers.

[0078] Within this specification, embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention. For example, it will be appreciated that the features described herein are applicable to all aspects of the embodiments described herein. Further, it is to be understood that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the description or illustrated in the drawings. For example, although two channels are illustrated here, it will be apparent that the system and method described above can be used to form varying numbers of channels, and varying shapes of channels. Further, the system described above can be used to produce discrete absorbent core products, or a continuous product with channels formed- 17 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078 therein. Additionally, although a specific series of steps is described, it will be apparent that the order of these steps can be varied, and that not all steps are required for all processes. For example, a non-woven substrate may or may not be used in constructing a core, and a closing sheet may or may not be added to the core.

[0079] Further, although the system is described as including a forming drum and a transfer drum, the absorbent core can also be formed on a substantially flat permeable plate. The formed core can then be transferred via a conveyor or other suitable device to a second plate, the second plate including a permeable channel forming portion formed therein in a predetermined shape or pattern of a channel or channels. A vacuum source can then be directed at the permeable channel forming portion to withdraw material from the absorbent core to form a channel or channels, as described above. A channel forming ridge can circumscribe the permeable channel forming portion of the horizontal plate, as described above with reference to channel forming unit 30.

[0080] The present disclosure is capable of other configurations and of being practiced or of being carried out in various ways. Thus, it will be appreciated by those skilled in the art that, while the disclosure has been described above in connection with particular non-limiting examples and examples, the disclosure is not necessarily so limited, and numerous other constructions, examples, uses, modifications and departures from the non-limiting examples, examples and uses are intended to be encompassed by the claims attached hereto. The figures, similarly, depict selected configurations and are not intended to limit the scope of the present disclosure. The present disclosure is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0081] Various features and advantages of the invention are set forth in the following claims.- 18 -QB\91641592 1

Claims

International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.00078CLAIMSWe claim:

1. An apparatus for forming an absorbent core with a channel formed therein, the apparatus comprising: at least one vacuum source; a permeable forming surface in communication with the at least one vacuum source, the vacuum source configured to draw absorbent material onto the permeable forming surface to form an absorbent core; and a channel forming surface configured to receive the absorbent core at a location downstream in a machine direction from the permeable forming surface, the channel forming surface comprising a permeable channel forming portion shaped in a pre-determined shape corresponding to a channel to be formed in the absorbent core, the permeable channel forming portion in communication with the at least one vacuum source such that absorbent material is withdrawn from the absorbent core to form a channel of the predetermined shape therein when vacuum is drawn through the permeable channel forming portion.

2. The apparatus of claim 1, wherein the permeable forming surface is located on a first rotating drum and the channel forming surface is located on a second rotating drum, downstream of the first rotating drum in the machine direction.

3. The apparatus of claim 1, wherein the channel forming surface is located on a rotating pad, downstream of the permeable forming surface in the machine direction.

4. The apparatus of claim 1, wherein the channel forming surface is located on a belt of a conveyor, downstream of the permeable forming surface in the machine direction.

5. The apparatus of claim 1, wherein the permeable channel forming portion comprises an aperture in fluid communication with an interior vacuum chamber of one of a rotating drum and a rotating pad.- 19 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.000786. The apparatus of claim 1, wherein the permeable channel forming portion of the channel forming surface is circumscribed by a channel forming ridge extending from the outer surface of the channel forming surface.

7. The apparatus of claim 6, wherein the channel forming ridge is made of a compliant material.

8. The apparatus of claim 6, wherein the channel forming ridge is made of a rigid material.

9. The forming system of claim 6, wherein the outer edges of the channel forming ridge are radiused.

10. An apparatus for forming an absorbent core with a channel formed therein, the apparatus comprising: at least one vacuum source; a forming drum comprising a permeable outer surface, the permeable outer surface in communication with the at least one vacuum source, the forming drum configured to rotate in a first direction; a forming chute coupled adjacent an outer surface of the forming drum and configured to deliver an absorbent material to the surface of the forming drum to form an absorbent core; a channel forming unit positioned downstream from the forming drum in a machine direction, an outer surface of the channel forming unit including a permeable channel forming portion shaped to correspond to a pre-determined shape of at least one channel, the permeable channel forming portion being in communication with the at least one vacuum source; and wherein absorbent material is withdrawn from the absorbent core to form at least one channel in the shape of the permeable channel forming portion of the outer surface of the channel forming unit in the absorbent core when vacuum is drawn through the permeable channel forming portion.- 20 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.0007811. The apparatus of claim 10, wherein the permeable channel forming portion of the channel forming unit is circumscribed by a channel forming ridge extending from the outer surface of the channel forming unit.

12. The apparatus of claim 11, wherein the channel forming ridge is made of a compliant material.

13. The apparatus of claim 11, wherein the channel forming ridge is made of a rigid material.

14. The apparatus of claim 11, wherein the outer edges of the channel forming ridge are radiused.

15. The apparatus of claim 11, wherein the at least one vacuum source comprises first and second vacuum sources, and wherein the first vacuum source is in communication with the forming drum, and the second vacuum source is in communication with the permeable channel forming portion.

16. A method for forming an absorbent core with at least one channel formed therein, the method comprising the following steps: positioning a source of absorbent material adjacent a permeable surface; applying a vacuum to the permeable surface to draw the absorbent material onto the permeable surface to form an absorbent core; positioning the absorbent core adjacent a channel forming surface including a permeable channel forming portion shaped in a predetermined shape of a channel to be formed in the absorbent core; and drawing a vacuum through the permeable channel forming portion to withdraw absorbent material from the absorbent core.- 21 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.0007817. The method of claim 16, further comprising the step of circumscribing the permeable channel forming portion of the channel forming surface with a channel forming ridge extending from the outer surface of the channel forming surface.

18. The method of claim 16, further comprising the step of pulling the withdrawn absorbent material through the permeable channel forming portion and into an interior chamber of one of a channel forming unit having the permeable channel forming portion formed on an outer surface thereof.

19. The method of claim 16, further comprising positioning the absorbent core adjacent a vacuum drum having the channel forming surface integrally formed thereon.

20. The method of claim 16, further comprising positioning the absorbent core adjacent a rotating vacuum transfer pad having the channel forming surface integrally formed on an outer surface thereof.

21. A channel forming unit for use in a system for forming an absorbent core, the channel forming unit comprising: a substrate comprising a permeable channel forming portion shaped to correspond to a predetermined shape of at least one channel to be formed in an absorbent core; and an upwardly extending channel forming ridge circumscribing the permeable channel forming portion, a height of the ridge being selected to correspond to a depth of the at least one channel to be formed in the absorbent core.

22. The channel forming unit of claim 21, wherein the substrate is an outer surface of a rotatable drum having an interior vacuum chamber.

23. The channel forming unit of claim 21, wherein the substrate is an outer surface of a vacuum transfer pad.- 22 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.0007824. The channel forming unit of claim 21, wherein the substrate comprises an outer surface of an insert coupleable to a surface of a vacuum transfer pad or a rotatable drum.

25. The channel forming unit of claim 21, wherein the substrate is formed to correspond to a surface of a vacuum transfer pad or a surface of a rotatable drum.

26. The channel forming unit of claim 21, wherein the permeable channel forming portion comprises at least one aperture in fluidic communication with an interior vacuum chamber of the channel forming unit, and wherein the at least one aperture comprises one of a continuous void and an air permeable screen.

27. The channel forming unit of claim 21, wherein the substrate comprises apertures for receiving fasteners to couple the substrate to a surface of a vacuum transfer pad or a surface of a rotatable drum.

28. The channel forming unit of claim 21, wherein the upwardly extending channel forming ridge comprises a compliant material.

29. The channel forming unit of claim 28, wherein the upwardly extending channel forming ridge comprises one or more of a rubber, silicone rubber, polyurethane, a thermoplastic polyamide, a thermoplastic polyurethane, a thermoplastic elastomer, and a neoprene foam.

30. The channel forming unit of claim 21, wherein the outer edges of the upwardly extending channel forming ridge are radiused.

31. The channel forming unit of claim 21, wherein the channel forming ridge has a crosssection that is triangular in shape, with the base of the triangle adjacent the surface of the substrate and an opposing vertex directed away from the substrate.- 23 -QB\91641592 1International Patent Application JOA Ref. 1000.345 PCT Attorney Docket No. 510169.0007832. The channel forming unit of claim 21, wherein the channel forming has a generally rectangular cross-section.

33. The channel forming unit of claim 21, wherein a plurality of permeable channel forming portions are formed in the substrate.- 24 -QB\91641592 1

Images