STABILITY IMPROVED HYGIENE PROTECTOR

Abstract: This invention describes an embodiment of an absorbent hygiene protector such as Panty liner, String Pantyliner, Light incontinence, or Sanitary napkin with an inner layer (1) permeable to liquid an outer layer (7) essentially impermeable to liquid made of an expanded polymer with a thickness between 0.2-2.5 mm a density between 5-40 kg/m<3> and a bending resistance between 0.05-2.5 g/cm and an absorbtion body (2) located between the outer and inner layer.

Description: STABILITY IMPROVED HYGIENE PROTECTOR Hygiene protection covers such as Panty liners, Sanitary napkins and light incontinence products can be made very thin without loosing absorbent capacity by the incorporation of superabsorbent in the absorbent bat. however the lack of stability often restrains the possibility to make a very thin product. In many products the need for a large absorption capacity is small. The problem with these kinds of light products is the lack of stability, they wrinkle easily especially in wet condition. In order to achieve a sufficient stability a heavier absorbent body than necessary for the needed absorbent capacity is often used. The absorbent body accounts for most of the material cost in these products. In order to get a good rewet and dryness superabsorbents are often included in the absorbent body. These superabsorbents can be made of crosslinked Acrylate polymers or crosslinked Carboximethylcellulose and are normally blended or placed in the absorbent body, which usually consists of cellulose fibers in form of a fluff. The manufacture of the cellulose fluff can be made in conjunction with the converting equipment where the cellulose fibers are defibrated into a fluff in a special mill and formed on top of a conveyer belt to appropriate thickness and dimension. Absorbent bodies are also to a large extend made as an air laid core in special machines too jumbo rolls, which in its turn are converted to smaller sizes suitable for the manufacturing process of hygiene products. These absorbent bodies can but do not necessary have to contain additives of different kinds such as Latex or melt fibers in order to improve the strength of the body. However, all these absorbent bodies have a very poor stability, especially in wet condition. SHORT DESCRIPTION OF THE FIGURES. Fig. 1 shows the state of the art of a hygiene protector seen from above where (1) shows the inner layer to be situated nearest to the body of the user (2) shows the absorbent body situated under the inner layer (1). Fig. 2 shows a cut through fig. 1 along the line A-A where (1) is the inner layer situated nearest to the body of the user (2) is the absorbent body (3) is the outer layer, a liquid impermeable thin plastic film, (4) shows the glue binding the different layers (1,2,3) together. (5) is a self tacking glue to be fastened to the briefs of the user after the release paper (6) has been removed. Fig. 3 shows an example of a design made according to the invention seen from above where (1) is the inner layer situated nearest to the body of the user and (2) is the absorbent body. Fig.4 shows a cut through fig. 3 along the line B-B where (1) is the inner layer situated nearest to the body of the user. (2) is the absorbent body, (7) is the outer layer according to this invention (4) shows the adhesive that binds the different layers (1,2,7) together, (5) is a self tacking glue to be fastened to the briefs of the user after the release paper (6) has been removed. Fig.5 shows a folded specimen (9) under a load (8). Fig.6 shows test equipment to measure the bending resistance were (13) is a scale (12) the scale platen (10) the top platen for the test specimen (9) to be pressured against when measuring the bending resistance. Fig. 7 shows an example of the invention on a tanga or string panty liner . Fig.8 shows a cut through line A-A in fig.7 where (1) is the inner layer situated nearest to the body of the user (2) the absorbent body and (7) is an outer layer according to this invention. These figures only show some examples of possible embodiments of the invention were several other layers could be included for example tissue acquisition layers and other materials well known to men skilled in the art. SUMMARY OF THE INVENTION This invention describes an embodiment of an absorbent hygiene protector such as inner layer (1) permeable to liquid an outer layer (7) essentially impermeable to liquid made of an expanded polymer with a thickness between 0.2 - 2.5 mm. density between 5 -40 kg/m3 and a bending resistance in LD (Longitudinal direction) or TD (Transversal direction) between 0.05- 2.5 g/cm and an absorbtion body (2) located between the outer and inner layer. DESCRIPTION OF THE INVENTION A hygiene protector consisting of a liquid permeable inner layer ( 1 ) situated nearest to the body of the user, such as Nonwoven made of Polypropylene. Polyester, Polyethylene. PVC, Viscose or other for the use suitable materials or mixes thereof with a surface weight between 5-45g/m2, or perforated plastic film made of such materials as Polypropylene, Polyester, Polyethylene, Polyvinyl chloride, or other for the purpose suitable polymers or polymer mixes with a weight of 5-45g/m2 or combinations thereof. Tissue layers (4) fig. 4 with a weight between 10-40g/m2 can also be placed between the inner layer (1) and the absorption body (2) and the outer layer (7). The inner layer (1) can be abandoned if the absorbtion body (2) is of a good enough quality to be situated in direct contact with the users skin. An acquisition layer made of high loft nonwoven can also be placed between the inner layer (1) and the absorbent body (2) to improve absorption speed and rewet properties. The absorption body (2) is preferably made of cellulose fluff, airlaid or non-airlaid, cotton or mixes of cotton and synthetic fibers. The absorption body can also be made of one or more layers of tissue or embossed soft paper. The total surface weight of the absorbent body can be varied between 15-250 g/m2, preferably 20-150 g/m2 and contain superabsorbents in a granular, powder or fiber form. The weight of these superabsorbents can vary between 0-80 % of the total weight, preferably 0- 70 %. Superabsorbents are well known to the men skilled in the art. These materials described shows different examples of suitable material combinations and can be varied by a person skilled in the art within the scoop of this invention. The outer layer (7) according to the invention is made of a water impermeable expanded polymer with closed or partly closed cells. It can be made of any kind of polymer such as Polyester, Polyvinyl chloride ,Biodegradable starch polymers, Ethylene vinylacetat. Ethylene methylakrylate. Ethylene ethylacrylate. Polyethylene. Polypropylene or copolymers thereof, preferably Polyethylene or Polypropylene, or other for the purpose suitable polymers having a thickness between 0.2-2.5 mm, a density between 5-40 kg/m3 and a specific bending resistance of between 0.05- 2.5 g/cm (se separate description of test method for bending resistance). The outer layer can also be made moisture permeable by means of using moisture permeable polymers or by means of being made micro porous in the manufacturing process. The water vapor permeability in such an outer layer can vary between 200- 10000g/m2/24 hours. Preferably between 1000- 6000g/m2/24 hours. The outer layer can also have a thin layer of plastic film or nonwoven on the outside of the layer. DESCRIPTION OF TEST METHOD FOR MEASURING OF THE BENDING RESISTANCE. A 5x5cm specimen is cut from the product or the material to be tested. The specimen is placed on top of a flat surface and a suitable amount of test fluid is applied with a pipette in the center of the specimen at the same time as a stopwatch is started. After one minute absorption time inclusive the application time of the test fluid, the specimen is double folded in the Longitudinal direction hereinafter called LD fig.5 (9) and a weight of 1.5 kg (8) is placed on top of the double folded specimen for a time of two minutes, after that the specimen is placed on top of a scale platen (12) fig.6. A rig (10) of at least 6-cm width is placed on the top of the scale surface (1 1) so it presses the double folded specimen (9) against the scale platen (12), which is situated at a distance of 1 1 mm from the rig (10). The pressure force of the specimen against the scale is noted after one minute's time and is a measurement of the specimens bending resistance. The test procedure is repeated in the transverse direction hereinafter called TD. The measurements are also made as described with a dry specimen. The results are presented as the bending resistance in g/cm with 2 decimals. Test fluid (Synthetic blood) Carboxy Metyl Cellulose. Natrium 0.46 % Glycerol water free purum 10% Sodium chloride 1% Coloring agent Rodamin B 0.01 % Aqua Dest. to 100 % Example 1 made according to the invention Hygiene protector with a length of 155 mm and a width of 70 mm and a neck of 50 mm with a total weight of 1.6g where all layers are joined together with hot melt and forms a homogenous unit consisting of an inner layer with a surface weight of 23g/m2 attached to an absorbent body made of airlaid cellulose without superabsorbents and of a surface weight of 90g/m2 and bottom layer made of expanded polyethylene with a surface weight of 20g/m2 a thickness of 1mm and a density of 20 kg/m3. The pantyliner also has an adhesive layer made of tree parallel 5mm wide strings stretching along the whole length of the back of the pantyliner covered with a siliconiced release paper with a weight of 40g/m2. The bending resistance of a 50x50mm specimen without release paper is 0.69g/cm in LD and 0.87 g/cm in TD in dry condition. In wet condition with a dosage of 0.5 ml synthetic blood the bending resistance in LD is 0.24g/cm and in TD 0.5g/cm. Comparison A comparative measurement of a commercial pantyliner Inlegkruises from Trekpleister in Holland with exactly the same composition as example 1 with the exemption of layer (7) fig.4 is which was replaced with a standard Polyethylene film with a weight of 22g/m2 and a density of 922kg/m3, gave the following results. Dry condition LD 0.13 g/cm LD 0.21 g/cm. Wet condition LD 0.026 g/cm LD 0.064g/cm. As can be seen from the comparison the bending resistance of example 1 was improved 5,3 times in LD and 4.1 times in TD in dry condition. In wet condition the improvement was 9,2 times in LD and 7,8 times in TD. Example 2 made according to the invention A hygiene protector with a length of 155 mm and a width of 50 mm made of a inner layer of a 23g/m2 nonwoven (PellyluxPPF23, Germany) laminated with an air laid cellulose of a weight of 90g/cm2 including 15 % by weight of superabsorbents (Walkisoft AL T 576) laminated with an expanded polyethylene layer with a surface weight of 20g/cm2, thickness of 1 mm and a density of 20kg/m3 (Fawolen PD 120 from Fagerdala Sweden). The bending resistance of this composition is in dry condition LD 0,87 g/cm in TD l,2g/cm, in wet condition with a dosage of 1-ml synthetic blood, LD 0.29-g/cm TD 0,65 g/cm. Comparison The same composition as example 2 was made with the exception of that the expanded polyethylene was replaced with a standard Polyethylene film for this type of products with a thickness of 0.02 mm. Thee bending resistance for this composition in dry condition was in LD 0,21 g/cm and in TD 0,33g/cm. In wet condition with the dosage of 1 ml synthetic blood in LD 0.06 g/cm and in TD 0,081 g/cm. As seen from the comparison with example 2 of the invention the bending resistance improves 4,1 times in LD and3,6 TD in dry condition and in wet condition 4,8 times in LD and 8,0 times in TD. As can be seen from these tests standard designs of hygiene products has a catastrophic loss of stability especially in wet condition, but the design according to the invention improves the product stability substantially. Example 3 made according to the invention Fig. 7 shows a string or tanga panty liner according to the invention with a length of 150 mm, a width of 60 on its widest part and a width of 25 mm on its narrowest part. Fig. 8 shows a cut through fig. 7 along the line A-A where (7) is an expanded polyethylene with a surface weight of 20g/m2 thickness of 1 mm and a density of 20kg/m3. (FawolenPD120, Fagerdala AB, Sweden.) The absorbent body is made of an air laid cellulose with a surface weight of 55g/m2 (TL5552, Duni AB Sweden) without superabsorbents The cower stock is a spunlaid Polypropylene nonwoven (HO022, Fiberweb Sweden) of a standard quality with a surface weight of 22g/m2. The bending resistance in dry condition is 0.75g/cm in LD and 1,0 g/cm in TD. In wet condition with a dosage of 0.5 ml synthetic blood is the bending resistance in LD is 0,28g/cm and in TD 0.54g/cm. This invention is especially suited for improvement of the function of so called tanga or string pantyliners (se. US pat. design no. 366.524 or German Gebrauchmuster 295 13 548) since the back part of these pantyliners are very narrow and sensitive to bending and deformation. These examples show some typical embodiments of the invention. However many different combinations of absorbent bats with different weights and sizes can be used in combination with the expanded polymer according to the invention to achieve an improvement of the product stability in order to minimize the risk for leakage and to get a more comfortable and functional product for the user. A suitable bending resistance in either LD or TD in wet condition for products made according to the invention, is between 0.1-3.5 g/cm

Claims: I CLAIM 1. A hygiene protector made of an inner layer permeable to liquid (2) an outer layer essentially impermeable to liquid (7) and an absorbtion body (2) located between the outer and inner layer characterized in that the outer layer is made of an expanded polymer with a thickness between 0.2 - 2.5 mm having a density between 5 -40 kg/m3 and a bending resistance between 0.05-2,5 g/cm. 2. A Hygiene protector according to claim 1 characterized in that the expanded polymer is made mainly of Polyethylene or Polypropylene. 3. A Hygiene protector according to claim 1-2 characterized in that the expanded polymer is made mainly of closed cells. 4. A Hygiene protector according to claim 1 - 3 characterized in that the inner layer is made of nonwoven or perforated plastic film with a surface weight between 10 -45 g/m2 5. A Hygiene protector according to claim 1 -4 characterized in that the absorbent body is made of air laid cellulose fluff with a surface weight of between 15 - 250 g/m2. 6. A Hygiene protector according to claim 1 -4 characterized in that the absorbent body is made of cellulose fluff with a surface weight of between 15 - 250 g/m2. 7. A Hygiene protector according to claim 1-4 characterized in that the absorbent body is made of embossed soft paper in one or several layers with a total surface weight between 15 and 250 g/m2. 8. A Hygiene protector according to claim 1 -4 characterized in that the absorbent made of cellulose tissue in one or several layers with a total surface weight between 15 and 250 g/m2. 9. A Hygiene protector according to claim 1 - 8 characterized in that the absorbent body has a content of 0 -80 % superabsorbents. 10. A Hygiene protector according to claim 1 -9 characterized in that the outer layer has water vapor permeability between 1000- 6000g/m2/24 hours 1 1. A Hygiene protector according to claim 1-10 characterized in that specific bending resistance in wet condition is between 0.1- 3,5g/cm in the transversal or longitudinal direction. 12. A Hygiene protector according to claim 1-1 1 characterized in that the protector is a tanga or string panty liner.

Inventors: BJOERNBERG STEN GUNNAR, BJOERNBERG, STEN, GUNNAR
Applicants: BJOERNBERG STEN GUNNAR, BJOERNBERG, STEN, GUNNAR
Application year: 2000
Main classification: A61F13
IPC codes: A61F5, A61F13