权利要求：
1. An absorbent core (101) comprising: a front portion (122); a back portion (124); a crotch portion (126) position between the front portion (122) and the back portion (124); and a longitudinal axis extending along a length of said core (101) and crossing said front, crotch and back portions (122, 126, 124), the absorbent core (101) having a width extending perpendicular to said length and a perimeter comprising at least two opposing ends (102, 103) and at least two opposing sides (104, 105) positioned between said ends (102, 103) characterized in that the absorbent core (101) comprises one or more substantially interconnected channels (106) extending through the crotch portion (126) along and substantially parallel to the longitudinal axis and further extending along at least a portion of said width of the core from one side of the core to the other, preferably said one or more substantially interconnected channels (126) being symmetric or asymmetric about the longitudinal axis, wherein at least one of the interconnected channels (106), preferably each of said channels (106), forms a shape having a closed end in the form of a U-bend, preferably wherein the closed end is positioned proximal to the back portion (124) of the absorbent core (101).
2. An absorbent core according to Claim 1 wherein at least one of the interconnected channels (106), preferably each said channel (106), forms a shape having an open end in the form of two diverging ends or a funnel-shape, preferably wherein the open end is positioned proximal to the front portion (122) of the absorbent core (101) and distal from said closed end.
3. An absorbent core (101) according to any of the preceding claims, wherein at least one of the interconnecting channels (106) comprises: a first channel portion (107) extending substantially along the longitudinal axis proximal to a first side (104) of the core (101); a second channel portion (108) extending substantially along the longitudinal axis proximal to a second side (105) of the core (101); and at least one, preferably only one, connecting channel portion (109) in fluid communication with said first and second channel portions (107, 108) and forming said closed end in the form of a U-bend, preferably wherein the first and second channel portions (107, 108) diverge away from the longitudinal axis at least along a portion of the interconnecting channel (106) exiting from the U-bend, thereby at least partially forming a funnel-shaped interconnected channel near the closed end.
4. An absorbent core (101) according to any of the preceding Claims wherein each substantially interconnected channel (106) comprises: a first channel portion (107) extending substantially along the longitudinal axis proximal to a first side (104) of the core (101); a second channel portion (108) extending substantially along the longitudinal axis proximal to a second side (105) of the core (101); and at least one, preferably only one, connecting channel portion (109) in fluid communication with said first and second channel portions (107, 108).
5. An absorbent core (101) according to Claim 3 or 4 wherein the connecting channel portion (109) extends substantially along the width of said core (101), preferably forming a closed end shape within a surface of said core (101) along a plane parallel to the longitudinal axis, and preferably positioned opposite to an open end shape formed by non-connected first and second terminal positions (110,111) of the interconnected channel (106), preferably of the first and second channel portions (107, 108) respectively, typically said non-connected first and second terminal positions (110, 111) being distal to each other and proximal to the first and second sides (104, 105) of said core (101) respectively, even more preferably said terminal positions (110, 111) facing away from each other such to form a funnel-shaped gap therebetween.
6. An absorbent core (101) according to Claim 5 wherein the closed end is substantially curvilinear in shape, preferably forming a convex shape between the first and second channel portions (107, 108), or is substantially linear in shape, preferably forming a straight or triangular shape between the first and second channel portions (107, 108).
7. An absorbent core (101) according to any of the preceding Claims having a first distance (d1) between the first channel portion (107) and the second channel portion (108), a second distance (d2) between the first channel portion (107) and the second channel portion (108), wherein the first distance (d1) is proximal to the front portion (102) of the core (101) and the second distance (d2) is proximal to the back portion (103) of the absorbent core (101), and wherein the first distance (d1) is greater than the second distance (d2), preferably wherein the first distance (d1) is at least 1.5d2, more preferably from 1.8d2 to 3d2.
8. An absorbent core (101) according to any of the preceding claims comprising a first nonwoven web, typically in the form of a backsheet; a second nonwoven web, typically in the form of a topsheet; and a three-dimensional absorbent material positioned between the first and second nonwoven webs to form an absorbent core laminate, typically wherein the three-dimensional absorbent material comprises a fibrous web typically comprising airlaid fibers, and preferably comprises a predetermined amount of super absorbent polymer dispersed therethrough.
9. An absorbent core (101) according to any of the preceding Claims wherein the interconnected channel (106) is substantially free of three-dimensional absorbent material.
10. An absorbent core (101) according to any of the preceding Claims wherein the substantially interconnected channels (106) have a regular or irregular depth, said depth being measured on an axis perpendicular to both the longitudinal axis and the axis along the width of the core (101), preferably wherein the cross-section of said channels (106) is selected from the group consisting of curved, polygonal or combinations thereof.
11. An absorbent article (10, 20, 300) comprising a core (101) according to any of the preceding Claims, preferably said article being selected from disposable diapers or diaper pants; disposable incontinence diapers or diaper pants; sanitary napkins; or panty liners; and typically wherein the channels in said core remain visible both before and after use of the article, preferably wherein the channels are more visible after use than before use of the article.
12. Use of an absorbent core according to any of Claims 1 to 10 in an absorbent article according to Claim 11, for improved liquid distribution compared to the same absorbent article comprising a core free of substantially interconnected channels.
13. Use of an absorbent core according to any of Claims 1 to 10 in an absorbent article according to Claim 11, for providing a tri-stage fluid distribution comprising a first fluid distribution at a first speed, a second fluid distribution at a second speed and a third fluid distribution at a third speed, said first speed being greater or equal to said second speed and said third speed being less than said first speed and less than or equal to said second speed, preferably wherein the first fluid distribution is driven by the substantially interconnected channels, the second fluid distribution is driven by a three-dimensional absorbent material comprised within the core, and the third fluid distribution is driven by an amount of super absorbent polymer dispersed within the three-dimensional absorbent material.
14. A process of making an absorbent core (101) comprising the steps of: i. providing a mold comprising a 3D insert therein, said 3D insert being the inverse shape of the desired channels, wherein substantially the entire surface of the mold is in fluid communication with an under-pressure source except for the 3D insert; ii. applying a first nonwoven web to said mold; iii. applying a three-dimensional absorbent material over at least a portion of said nonwoven; iv. applying a second nonwoven web directly or indirectly over the three-dimensional absorbent material; v. optionally applying a bonding step to form a laminate comprising said first nonwoven, said second nonwoven and said three-dimensional absorbent material therebetween; vi. optionally removing said laminate from the mold to form an absorbent core comprising channels having the inverse shape of said 3D insert; and characterized in that at least for the duration of step iii the underpressure source is arranged to provide a vacuum force forcing said three-dimensional absorbent material around the 3D insert such to substantially evacuate the surface thereof from three-dimensional absorbent material and form channels substantially free of three-dimensional absorbent material.
15. A process according to Claim 14 wherein the bonding step comprises applying an adhesive on a surface of the second nonwoven web and joining said web to said first nonwoven web and/or three-dimensional absorbent material, preferably the adhesive being applied in continuous or discontinuous spaced apart stripes aligned with said channels such that the resulting core laminate comprises adhesive rich and adhesive poor regions, wherein the adhesive rich regions are substantially located along said channels and the adhesive poor regions are located in areas of the core other than said channels.
16. A process according to Claims 14 to 15 wherein the channels substantially free of absorbent material are formed only by action of said vacuum force and no additional mechanical action such as embossing or mating of one or more mating parts or mating strips.