Absorbent article with an absorbent core having two longitudinally extending side regions and a longitudinally extending central region between said side regions and method for manufacturing said absorbent article
11285053 · 2022-03-29
Assignee
Inventors
- Prelo M. Hood (Philadelphia, PA, US)
- Paul Coomes (Philadelphia, PA, US)
- Mariela Biber (Newark, DE, US)
- Peter Kacenak (Hôrka, SK)
Cpc classification
A61F13/4704
HUMAN NECESSITIES
International classification
A61F13/535
HUMAN NECESSITIES
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 and a longitudinally extending central region between said side regions. The central region and the side regions are spaced apart in the transversal direction by longitudinally extending channel regions. Furthermore, 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, at least in the front section and the rear section, and the channel regions are of less basis weight than the side regions and the central region.
Claims
1. An absorbent article having a longitudinal direction, a transverse direction and a thickness direction, and comprising 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, 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 longitudinally extending channel regions, 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, at least in the front section and the rear section, wherein the channel regions are of less basis weight than the side regions and the central region, wherein the channel regions and the side regions are of substantially the same thickness, and wherein the ratio between the basis weight of the channel regions and the basis weight of the side regions and the central region of the absorbent core is between 1:3 and 2:3.
2. An absorbent article according to claim 1, wherein the article is an incontinence liner having a single absorbent core.
3. An absorbent article according to claim 1, further comprising an acquisition layer generally covering said absorbent core.
4. An absorbent article according to claim 1, 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.
5. An absorbent article according to claim 1, wherein said absorbent core comprises superabsorbent material being generally equally distributed along said absorbent core.
6. An absorbent article according to claim 5, wherein the amount of said superabsorbent material in said absorbent core is within the interval 25-55% of the total weight of the absorbent core.
7. An absorbent article according to claim 1, wherein said article comprises a crotch region, a front region and a back region, and wherein the width of the central region is less than the width of the side regions in said crotch region.
8. An absorbent article according to claim 1, wherein said channel regions are generally parallel and straight along the longitudinal direction of the absorbent core.
9. An absorbent article according to claim 1, wherein the width of each channel region is 2-3 millimeters.
10. An absorbent article according to claim 1, wherein the width of the central region is 6-12 millimeters.
11. An absorbent article according to claim 1, wherein the width of each channel region is less than 0.4 times the width of a corresponding side region.
12. An absorbent article according to claim 1, wherein the width of each channel region is less than 0.1 times the width of the absorbent core at a most narrow region of the absorbent core.
13. An absorbent article according to claim 1, wherein the channel regions are formed in the core by deposition of core material, said deposition of core material being relatively less in the channel regions as compared to the deposition of material in other areas of the core.
14. An absorbent core for use in an absorbent article having a longitudinal direction, the absorbent core comprising 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 a transversal direction by longitudinally extending channel regions and, in the longitudinal direction, a front section, a rear section and a crotch section between the front section and the rear section, 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, at least in the front section and the rear section, wherein the channel regions are of less basis weight than the side regions and the central region, wherein the channel regions and the side regions are of substantially the same thickness, and wherein the ratio between the basis weight of the channel regions and the basis weight of the side regions and the central region of the absorbent core is between 1:3 and 2:3.
15. An absorbent article according to claim 1, wherein the channel regions and the side regions and the central region are of substantially the same thickness throughout at least an entirety of the crotch section.
16. An absorbent article according to claim 15, wherein a density of the channel regions is lower than a density of the side regions and the central region throughout at least an entirety of the crotch section.
17. An absorbent core according to claim 14, wherein the channel regions and the side regions and the central region are of substantially the same thickness throughout at least an entirety of the crotch section.
18. An absorbent core according to claim 17, wherein a density of the channel regions is lower than a density of the side regions and the central region throughout at least an entirety of the crotch section.
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)
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. Such articles also include baby diapers, pant diapers, training pants, belted diapers or similar disposable absorbent garments.
(13)
(14) Furthermore, an acquisition layer 5 (a high-loft layer) is situated between the topsheet 2 and the absorbent core 4. The acquisition layer 5 functions as an admission and transport 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 or incontinence pad. This is due to the fact that incontinence liners or incontinence pads may be 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 carded 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.
(24) Furthermore, according to an embodiment, the incontinence liner 1 includes an absorbent core 4 which consists of 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%, 35-50%, or 37-45%, 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 absorbent core 4 may further incorporate components for improving the properties of the absorbent core. Some examples of such components are binder fibers, fluid-dispersing materials, fluid acquisition materials, etc. as known in the art. In particular embodiments, the mixture of cellulose fluff pulp and superabsorbent articles is 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 may be made from 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 to 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 structure 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 regions 4b, 4c are defined by two generally straight lines, but according to alternative embodiments, may also be of curved shape or other suitable geometry.
(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 4d, 4e and a longitudinally extending central region 4a between the side regions 4d, 4e. Also, the central region 4a and the side regions 4d, 4e are spaced apart in the transversal direction by longitudinally extending channel regions 4b, 4c.
(34) According to an embodiment, and as shown in particular in
(35) According to an embodiment, a suitable ratio of the basis weight between the channel regions 4b, 4c and the remaining part of the absorbent core 4 is approximately 1:2.
(36) The purpose of the channel regions 4b, 4c 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 embodiments of the invention. Also, according to the shown embodiment, the width w of the central region 4a in the transversal direction is less than the width w.sub.s of each of the side regions 4d, 4e in the transversal direction, at least in the front- and rear section.
(37) With reference to
(38) Furthermore, the width w.sub.1, w.sub.2 of each channel region 4b, 4c is less than 0.4 times the width w.sub.s of a corresponding side region 4d, 4e. Also, the width w.sub.1, w.sub.2 of each channel region 4b, 4c is less than 0.1 times the width of the absorbent core 4 at its most narrow section, i.e. the crotch section 10.
(39) Furthermore, with reference to
(40) As mentioned above, and as shown in
(41) 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.
(42) Furthermore, in
(43)
(44) Furthermore, each core mold 14 is provided with two longitudinally extending narrow portions 19a, 19b which correspond to the positions of the two above-mentioned channel regions 4b, 4c forming part of the finished product.
(45) During operation of the arrangement shown in
(46)
(47) Due to the provision of the two longitudinally extending narrow portions 19a, 19b, no air can be drawn through the core 14 just where these portions 19a, 19b are located. Also, no fluff pulp material can be deposited where the portions 19a, 19b are located. However, as the layer of fluff pulp material increases in height, fluff pulp material will be deposited on the upper side of each one of said narrow portions 19a, 19b, i.e. as the absorbent core 4 is gradually being formed.
(48) The final form of the absorbent core 4 when it exits the core forming drum 12 will correspond to that shown in
(49) In summary, the channels 4b, 4c are formed in the core due to the specifically designed screens 15 and the narrow portions 19a, 19b, which cause relatively less core material to be deposited in the channel regions 4b, 4c as compared to the amount of material deposited in other areas of the core 4 (on a grams per square basis).
(50) As described, each core mold 14 is formed with an internal recess having the form of the finished absorbent core 4 and the internal recess may have a thickness of for example 3-6 mm, for example 4 mm, and the longitudinally extending narrow portion 19 may have a thickness of 1-3 mm, for example 2 mm.
(51) According to further embodiments, the process shown in
(52) In summary, the invention is particularly intended to be used as an incontinence liner and includes an absorbent core 4 which has a central region 4a with a transversal width w which is less than the width of each of its side regions 4d, 4e, and also having channel regions 4b, 4c being of less basis weight than the side regions 4d, 4e and the central region 4a. Such an incontinence liner 1 will give advantages regarding comfort and fit during use, in particular due to the fact that the pliability of the absorbent core 4 is improved as compared with prior art solution.
(53) 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.
(54) Test Method for Determining the Pliability of the Absorbent Article
(55) Test Method:
(56) Bending Mode (12-92)—test method for pliability
SUMMARY
(57) An absorbent article according to an embodiment of the invention and as specified below presents a decrease in product stiffness by at least 25%.
(58) Purpose and Field of Test Application:
(59) 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.
(60) Definition (Force):
(61) 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.
(62) Principle:
(63) 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.
(64) Equipment:
(65) TABLE-US-00001 Tensile testing equipment such as Lloyd LRX Load cell 20 N 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
(66) 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.
(67) Procedure:
(68) 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.
(69) Calculation:
(70) Maximum force should be registered. State the accuracy of the results by 1 decimal unit N.
(71) A more detailed description of the test method will now follow with reference to
(72) 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 comprises 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 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.
(73) 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.
(74) 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.
(75) 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.
(76) 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.
(77) 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.
(78) Measurement Results:
(79) 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 embodiments of the present invention. Both test series were based on a procedure involving 25 measurements.
(80) 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
(81) 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
CONCLUSION
(82) 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 an embodiment of the invention has a product stiffness or pliability which is 25.2% less than the conventional liner.