Absorbent article with an absorbent core having longitudinally extending side regions being spaced apart in the transversal direction by at least one longitudinally extending channel region, and method for manufacturing said absorbent article
11154438 · 2021-10-26
Assignee
Inventors
- Prelo M. Hood (Philadelphia, PA, US)
- Paul Coomes (Philadelphia, PA, US)
- Mariela Biber (Newark, DE, US)
- Peter Kacenak (Hôrka, SK)
Cpc classification
B32B2307/726
PERFORMING OPERATIONS; TRANSPORTING
A61F2013/5307
HUMAN NECESSITIES
A61F13/4704
HUMAN NECESSITIES
A61F13/5611
HUMAN NECESSITIES
A61F2013/4587
HUMAN NECESSITIES
International classification
A61F13/15
HUMAN NECESSITIES
Abstract
An absorbent article has a longitudinal direction, a transverse direction and a thickness direction, and includes a fluid permeable topsheet, a fluid impermeable backsheet and an absorbent core enclosed between the topsheet and the backsheet having, in the longitudinal direction, a front section, a rear section and a crotch section between the front section and the rear section. The absorbent core has two longitudinally extending side regions being spaced apart in the transversal direction by at least one longitudinally extending channel region. The channel region is of less basis weight than the side regions.
Claims
1. An absorbent article having a longitudinal direction, a transverse direction and a thickness direction, having, in the longitudinal direction, a front section, a rear section, and a crotch section between the front section and the rear section, and comprising a fluid permeable topsheet, a fluid impermeable backsheet, and an absorbent core enclosed between the topsheet and the backsheet, wherein the absorbent core comprises superabsorbent material being generally equally distributed along said absorbent core in an amount of 25-55% of the total weight of the absorbent core and has two longitudinally extending side regions and at least one longitudinally extending channel region, the two longitudinally extending side regions being spaced apart in the transversal direction by the at least one longitudinally extending channel region, wherein a ratio between the basis weight of the at least one channel region and the basis weight of the side regions of the absorbent core is between 1:3 and 2:3, and wherein the channel region extends along the entire length of the absorbent core.
2. The absorbent article according to claim 1, wherein the absorbent article is an incontinence liner having a single absorbent core.
3. The absorbent article according to claim 1, further comprising an acquisition layer generally covering said absorbent core.
4. The absorbent article according to claim 1, wherein the absorbent core comprises two or more longitudinally extending channel regions.
5. The absorbent article according to claim 4, wherein the absorbent core has two longitudinally extending side regions and a longitudinally extending central region between said side regions, the central region and the side regions being spaced apart in the transversal direction by said channel regions.
6. The absorbent article according to claim 5, wherein the width of the central region is less than the width of the side regions at least in the front section and the rear section.
7. The absorbent article according to claim 6, wherein the width of the central region in the transversal direction is less than the width of each of the side regions in the transversal direction also in the crotch section.
8. The absorbent article according to claim 4, wherein said channel regions are generally parallel and straight along a longitudinal direction of the absorbent core.
9. The absorbent article according to claim 5, wherein the width of the central region is 6-10 mm.
10. The absorbent article according to claim 1, wherein the width of the at least one channel region is less than 0.4 times the width of a corresponding side region.
11. The absorbent article according to claim 5, wherein the width of each channel region is approximately 2-3 millimeters.
12. The absorbent article according to claim 1, wherein the width of the at least one channel region is less than 0.1 times the width of the absorbent core at a most narrow region of the absorbent core.
13. The absorbent article according to claim 1, wherein the at least one channel region is formed in the core by deposition of core material, said deposition of core material being relatively less in the channel region as compared to the deposition of material in other areas of the core.
14. An absorbent core having a longitudinal direction for use in an absorbent article and having two longitudinally extending side regions and at least one longitudinally extending channel region, the two longitudinally extending side regions being spaced apart in a transversal direction by the at least one longitudinally extending channel region, said absorbent core also having, in the longitudinal direction, a front section, a rear section, and a crotch section between the front section and the rear section, wherein a ratio between the basis weight of the channel region and the basis weight of the side regions of the absorbent core is between 1:3 and 2:3, wherein the at least one channel region extends along the entire length of the absorbent core, and wherein said absorbent core comprises superabsorbent material being generally equally distributed along said absorbent core in an amount of 25-55% of the total weight of the absorbent core.
15. A method for manufacturing an absorbent core for use in an absorbent article having a longitudinal direction, a transverse direction and a thickness direction, said method comprising: providing a fluid permeable topsheet; providing a fluid impermeable backsheet; forming an absorbent core comprising superabsorbent material being generally equally distributed along said absorbent core in an amount of 25-55% of the total weight of the absorbent core having at least one longitudinally extending channel region, thereby defining two longitudinally extending side regions being spaced apart in the transversal direction by said channel region, wherein a ratio between the basis weight of the channel region and the basis weight of the side regions of the absorbent core is between 1:3 and 2:3, and wherein said channel region extends along the entire length of the absorbent core; and enclosing the absorbent core between the topsheet and the backsheet, wherein said absorbent core has, in the longitudinal direction, a front section, a rear section, and a crotch section between the front section and the rear section.
16. The absorbent article according to claim 1, wherein all materials in the absorbent core are homogeneously mixed throughout the absorbent core.
17. The absorbent core according to claim 14, wherein all materials in the absorbent core are homogeneously mixed throughout the absorbent core.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Embodiments of the invention will be described in greater detail below with reference to the figures shown in the appended drawings.
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS
(10) Different aspects of the present disclosure will be described more fully hereinafter with reference to the enclosed drawings. The embodiments disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein.
(11) With initial reference to
(12) However, it is to be understood that the principles of the present invention are equally applicable to any type of hygienic absorbent article. Such articles include various types of incontinence liners and pads, and also sanitary napkins, menstrual pads, panty liners or similar products which are worn inside a supporting panty or a holder. Such articles also include baby diapers, pant diapers, training pants, belted diapers or similar disposable absorbent garments.
(13)
(14) Furthermore, an acquisition layer 5 is situated between the topsheet 2 and the absorbent core 4. The acquisition layer 5 functions as a liquid inlet layer which is arranged on top of the absorbent core 4 and which is especially suitable for use in an absorbent article in the form of an incontinence liner. This is due to the fact that incontinence liners are normally used in situations where there is a discharge of a relatively high volume of fluid in a relatively short time.
(15) The components in the liner 1 may be connected to each other by conventional means such as by means of an adhesive, heat bonding or ultrasonic bonding.
(16) The various layers 2, 3, 4, 5 which form part of the absorbent article 1 will now be described more in detail, with reference primarily to
(17) According to an embodiment, topsheet 2 is formed by a fluid permeable nonwoven fabric or film which is made of thermoplastic synthetic fibers. The topsheet 2 is sufficiently fluid permeable to allow discharged body fluids such as urine to penetrate through the thickness of the topsheet 2 and then reach the acquisition layer 5 and the absorbent core 4 so as to be absorbed. Also, the topsheet 2 is manufactured from a material which is compliant and soft-feeling to the skin of the wearer.
(18) According to further embodiments, the topsheet may be manufactured from various web materials such as woven and nonwoven webs and films, foams, or combinations of the above-mentioned materials. The nonwoven materials to be used for the topsheet 2 may be for example spunbond nonwoven, carded resin bonded materials, carded through-air bonded materials, hydroentangled materials or thermobonded materials.
(19) According to further embodiments, the topsheet 2 may be perforated, i.e. may be provided with fluid permeable apertures, and may optionally also have elastic properties which allows it to be stretched in any direction. Furthermore, the topsheet 2 extends across generally the entire absorbent article 1. Also, the topsheet 2 may be a single layer, or a combination of two or more layers.
(20) Furthermore, the backsheet 3 is, according to an embodiment, constituted by a fluid-impermeable and breathable film of polyethylene. According to various embodiments, the materials which can be used for manufacturing the backsheet 3 include thin and flexible fluid impermeable plastic films, or fluid impermeable nonwoven materials, fluid impermeable foams and fluid impermeable laminates.
(21) According to the embodiment shown in the drawings, the backsheet 3 is formed by a single layer, but can alternatively be formed by a multi-layered structure, i.e. a laminate, wherein at least one layer is fluid impermeable. Furthermore, the backsheet 3 can optionally be elastic in either direction. Also, backsheet materials that are not fully fluid impermeable but only resistant to fluid penetration may be used, particularly in cases where relatively small amounts of urine are expected to be absorbed by the incontinence liner 1. According to further embodiments, the backsheet 3 may be breathable, implying that air and vapor may pass through the backsheet. Furthermore, the backsheet 3 may optionally have an outer, garment-facing surface of a textile material such as nonwoven.
(22) As indicated in
(23) Furthermore, according to the embodiment shown in the drawings, the incontinence liner 1 includes an absorbent core 4 which is formed by a single layer including fibres of cellulosic fluff pulp and superabsorbent particles. According to alternative embodiments, the absorbent core 4 can be made up of any suitable absorbent or fluid-absorbing material as known in the art, for example foam, fiber waddings and similar materials.
(24) Furthermore, according to an embodiment, the incontinence liner 1 includes an absorbent core 4 which includes a mixture of cellulosic fluff pulp and a suitable amount of superabsorbent particles. Such superabsorbent material is well known in the field of absorbent articles, and is constituted by a water-swellable and water-insoluble material which is capable of absorbing large quantities of fluid upon formation of a hydrogel. Normal superabsorbent materials are capable of absorbing fluids of at least 10 times its own weight. According to an embodiment, the amount of said superabsorbent particles corresponds to an amount within the interval 25-55%, or 35-50%, of the total weight of the absorbent core 4.
(25) The superabsorbents are mixed with cellulose fluff pulp so as to form the absorbent core 4. The mixture of cellulose fluff pulp and superabsorbent articles can be homogeneously mixed throughout the entire absorbent core 4.
(26) As mentioned above, the incontinence liner 1 also includes an acquisition layer 5 which functions as a liquid inlet layer and suitably includes synthetic fibers such as polyester or polypropylene and can suitably be manufactured by through-air bonding. According to an embodiment, the acquisition layer 5 is constituted by a 50 gsm through air bonded carded nonwoven material. In a particular embodiment, the acquisition layer 5 is laid directly on top of the absorbent core 4. The acquisition layer 5 is adapted for rapidly acquire and distribute gushes of liquid which may be quickly introduced into the absorbent core 4.
(27) According to further embodiments, the absorbent core 1 may be a homogeneous and continuous structure of the same type of material in a single layer, or may be a layered structure with laminates of the same or different materials.
(28)
(29) Furthermore, the topsheet 2 and the backsheet 3 are connected to each other in an edge joint 11 around the periphery of the absorbent core 4. Also, the absorbent core 4 is of a size having an area which is slightly smaller than the area of the topsheet 2 and the backsheet 3.
(30) The shape of the incontinence liner 1 as shown in
(31) According to an embodiment which is shown in
(32) According to the embodiment shown in the drawings, the channel region 4a is defined by one single, generally straight line, but according to alternative embodiments, may also be of curved shape or other suitable geometry. Furthermore, as shown in
(33) In summary, the absorbent article 1 according to the disclosed embodiment has a longitudinal direction, a transverse direction and a thickness direction, and includes a fluid permeable topsheet 2, a fluid impermeable backsheet 3 and an absorbent core 4 enclosed between the topsheet 2 and the backsheet 3. Furthermore, the absorbent core 4 has two longitudinally extending side regions 4b, 4c and a longitudinally extending channel region 4a.
(34) According to an embodiment, and as shown in particular in
(35) According to one embodiment, the channel region, during use of the absorbent article, has light basis weight areas of generally the same thickness as the side regions of the core and the central region. Since the channel region with the light basis weight area during this embodiment is of generally the same thickness as the side regions of the core, the channel region has, according to this embodiment, also less density than the side regions of the absorbent core. The density is measured with an applied pressure of 0.5 kPa. This means that the channel region 4a defines a region with less density than the remaining part of the absorbent core 4, i.e. a lower value corresponding to grams of material per square area (gsm), than the remaining parts of the absorbent core 4.
(36) According to an embodiment, a suitable ratio of the basis weight between the channel region 4a and the remaining part of the absorbent core 4 is approximately 1:2.
(37) The purpose of the channel region 4a is to contribute to an increase of the pliability of the absorbent core 4 and the ability for the absorbent article 1 to flex lengthwise. This is an important advantage of the invention.
(38) With reference to
(39) Furthermore, the width w of the channel region 4a is less than 0.4 times the width w.sub.s of a corresponding side region 4b, 4c. Also, the width w of the channel region 4a is less than 0.1 times the width of the absorbent core 4 at its most narrow section, i.e. the crotch section 10.
(40) Furthermore, with reference to
(41) As mentioned above, and as shown in
(42) According to alternative embodiments, the incontinence liner 1 can be provided with various types of fastening means in the form of frictional fasteners, mechanical fasteners such as the hook-and-loop fastener type or combinations of different types of fasteners, as known in the art.
(43) Furthermore, in
(44)
(45) Furthermore, each core mold 14 is provided with a longitudinally extending narrow portion 19 which corresponds to the position of the above-mentioned channel region 4a forming part of the finished product.
(46) During operation of the arrangement shown in
(47)
(48) Due to the provision of the longitudinally extending narrow portion 19, no air can be drawn through the core 14 just where this portion 19 is located. Also, no fluff pulp material can be deposited where the portion 19 is located. However, as the layer of fluff pulp material increases in height, fluff pulp material will be deposited on the upper side of said narrow portion 19, i.e. as the absorbent core 4 is gradually being formed.
(49) The final form of the absorbent core 4 when it exits the core forming drum 12 will correspond to that shown in
(50) In any case, the channel region 4a will have an overall basis weight of material which is less than the remaining parts of the absorbent core 4.
(51) In summary, the channel 4a is formed in the core due to the specifically designed screens 15 and the narrow portion 19, which cause relatively less core material to be deposited in the channel region 4a as compared to the amount of material deposited in other areas of the core 4 (on a grams per square basis). The longitudinally extending narrow portion 19 may have a thickness between 1-3 millimeters, for example 2 mm. The core mold may have a thickness of 3-6, for example 4 mm. By having a thickness of the narrow portion 19 of 0.5 the thickness of the core mold (from top of mold to screen bottom), the basis weight of the channel region will be about 0.5 the basis weight of the side regions.
(52) According to further embodiments, the process shown in
(53) In summary, an embodiment of the invention is particularly intended to be used as an incontinence liner and includes an absorbent core 4 which has a channel region 4a being of less basis weight than the remaining part of the absorbent core 4.
(54) The invention is not limited to the embodiment but can be varied within the scope of the appended claims. For example, the material and dimensions used for the different layers forming the absorbent article 1 can be varied as indicated above.
(55) According to an embodiment, the absorbent article may include two or more channel regions. In the event that two channel regions are used, they will be formed as two generally parallel lines extending along the entire length of the absorbent core, just as the single channel region extends as shown for example in
(56) Also, in an embodiment including two channel regions, two longitudinally extending side regions will be defined outside each channel region. In other words, the two side regions are spaced apart in the transversal direction by the two longitudinally extending channel regions and the central region between the channel regions. The width of the central region in the transversal direction may be less than the width of each of the side regions in the transversal direction. In a particular embodiment, the width of the two channel regions is approximately 2-3 millimeters, and the width of the central region is approximately 9 millimeters. However, variations may occur depending on the design of the absorbent article.
(57) Furthermore, the channel regions are of less basis weight than the remaining parts of the absorbent core, in a manner which is similar to the embodiment described with reference to
(58) Test Method for Determining the Pliability of the Absorbent Article
(59) Test Method:
(60) Bending Mode (12-92)—test method for pliability
(61) Summary:
(62) An absorbent article according to an embodiment of the invention and as specified below presents a decrease in product stiffness by at least 25%.
(63) Purpose and Field of Test Application:
(64) The test method is used to define the pliability, stiffness or resistance in a product, when the product is folded or bent in a fixture designed for the purpose. The test method should describe the force that is required to shape a product to match the body after being applied to underwear.
(65) Definition (Force):
(66) The force is defined as the resistance that occurs when the product, which is resting on a Teflon-covered lower fixture, is folded into the fixture by the downward moving metal wires in an upper fixture.
(67) Principle:
(68) The product rests freely on two horizontal, parallel, Teflon-covered supports. The sample is pressed down at the centerline of the product between the two supports using a tensile tester. The maximum force is then registered. A detailed description of the test process will follow below.
(69) Equipment:
(70) TABLE-US-00001 Tensile testing equipment such as Lloyd LRX Load cell 20N Speed 300 mm/min Crosshead movement 40 mm Upper fixture 12-92, produced by Essity Hygiene and Health AB, metal wire with a diameter of 3 mm Lower fixture 47-07, produced by Essity Hygiene and Health AB, cross-section of the supports is circular with a diameter of 10 mm and the distance between the center of the supports is 40 mm Talc such as baby powder Teflon tape PD 420, produced by Stokvis
(71) Sample Preparation: 1. The fixture should be fitted to the tensile tester. 2. Place product on the lower fixture. The upper fixture should be adjusted leaving a distance between the upper metal and the product. The product should have no contact with the upper fixture before start. 3. Press zero. 4. The release paper on the product should be removed before the test and the adhesive should be covered in talc to remove stickiness.
(72) Procedure:
(73) Place the product on the lower fixture with topsheet facing upwards. Center the product so that the upper fixture meets the product precisely in the center. Press start.
(74) Calculation:
(75) Maximum force should be registered. State the accuracy of the results by 1 decimal unit N.
(76) A more detailed description of the test method will now follow with reference to
(77) The equipment includes a base fixture 20 for supporting an article 1 to be measured, and an upper fixture 21 to be lowered down onto the article 1 when resting on the base fixture 20. The base fixture 20 includes a base means 22 including a holder for attachment to a tensile tester. The base means 22 is provided with two support means 23a and 23b. Each support means 23a, 23b includes two generally vertical bars and two horizontal bars 24a, 24b extending horizontally between the two generally vertical bars. The support means 23a, 23b are attached to the base means 22 in a position so as to lean somewhat towards each other. Hence, the distance between the centre of the support means 23a, 23b at the base means 22 is about 87 mm, and the distance between the centers of the support means 23a, 23b at the horizontal bars 24a, 24b is only 40 mm. The horizontal bars 24a, 24b extend horizontally and in parallel.
(78) The horizontal bars 24a, 24b are covered with Teflon® and have a circular cross-section with a diameter of 10 mm (including the Teflon). The surface of the horizontal bars 24a, 24b is smooth.
(79) The upper fixture 21 includes a holder 25 for attachment to a tensile tester, and a metal wire structure 26. The metal wire structure 26 includes a horizontal portion for contacting the product 1 when lowered towards the base fixture. The horizontal portion has a length of 140 mm. At its two ends, the horizontal portion is attached to vertically extending wire portions, having a length of 50 mm. Thereafter, the wire portions continue with angled wire portions, also having a length of 50 mm, and leaning towards each other such that the upper ends of the angled wire portions are separated by a distance of 90 mm. The angled wire portions are each followed by a second horizontal wire portion having a length of 50 mm. Finally, the second horizontal wire portions are attached to the holder 25. The distance between the second horizontal wire portions at the holder 25 is thus 90 mm. The metal wire 26 has a diameter of 3 mm, and is made of a rigid and inflexible material.
(80) The upper fixture 21 is arranged in relation to the base fixture 20 such that the metal wire structure 26 is generally parallel to the horizontal bars 24a, 24b.
(81) For testing, the fixtures 20, 21 are mounted to the tensile tester. The upper fixture is adjusted such that the distance between the horizontal metal wire and the uppermost side of the sample when resting on the base 22 of the base fixture is about 2 mm. With this distance, the sample may easily be positioned on the base fixture. The sample shall be positioned such that the upper fixture will impact the middle of the sample.
(82) For testing, the upper fixture is lowered towards the sample with a velocity of 200 mm/min, so as to push the product down between the horizontal supports. The test is finished when the entire product has been pushed down between the supports.
(83) Measurement Results:
(84) Table 1 below shows the measurement results for a conventional incontinence liner, whereas Table 2 below shows the measurement results for an incontinence liner in accordance with an embodiment of the present invention. Both test series were based on a procedure involving 25 measurements.
(85) TABLE-US-00002 TABLE 1 No. Load (N) No. Load (N) No. Load (N) No. Load (N) No. Load (N) 1 1.86486 2 1.81738 3 2.39533 4 1.93933 5 1.43223 6 1.91535 7 2.04369 8 1.67681 9 1.53327 10 1.73858 11 1.78109 12 2.01489 13 2.43191 14 1.86583 15 1.64176 16 1.31981 17 1.59838 18 1.84993 19 1.84104 20 1.84514 21 1.63777 22 1.59693 23 2.28303 24 2.39323 25 1.56197
(86) TABLE-US-00003 TABLE 2 No. Load (N) No. Load (N) No. Load (N) No. Load (N) No. Load (N) 1 1.05162 2 1.14510 3 1.22609 4 1.22405 5 1.82324 6 1.26744 7 1.23330 8 1.26420 9 1.60583 10 1.26853 11 1.14848 12 1.52239 13 1.29964 14 1.74673 15 1.46880 16 2.14818 17 1.20120 18 1.44238 19 1.17635 20 1.14173 21 1.79068 22 1.19458 23 1.31233 24 1.35722 25 1.36632
(87) Conclusion:
(88) In conclusion, it was noted that the mean value for the conventional incontinence liner was 1.8408 N, whereas the mean value for the incontinence liner according to an embodiment of the invention was 1.3771 N. This means that the liner according to the embodiment of the invention has a product stiffness or pliability which is 25.2% less than the conventional liner.