US 20040093671 A1
A hygiene mat principally consisting of a liquid absorbing layer (2, 4) with or without a liquid permeable surface layer (1) and a liquid barrier (3), consisting of expanded polymers with closed cells and low density, 5-40 kg/m3, and a specific resistance to bending of between 0.05 and 3.5 g/cm, and a thickness of between 0.2 and 3.5 mm. With this structure a hygiene mat is obtained at a low cost with very good comfort and stability.
1. A hygiene mat principally consisting of a liquid absorbing layer (2,4) with or without a liquid permeable surface layer (1) and a liquid barrier (3) consisting of expanded polymer, characterized in that the expanded polymer has a density of between 5 and 40 kg/m3 and a thickness of between 0.2 and 3.5 mm.
2. A hygiene mat according to
3. A hygiene mat according to
4. A hygiene mat according to any of claims 1-3, characterized in that the absorptive layer consists of one or several layers of absorption material (2,4), mainly of cellulose having a total basis weight of between 10 and 300 g/m2.
5. A hygiene mat according to any of claims 1-4, characterized in that the expanded polymer is provided with friction increasing adhesive on the outside (6,7,8).
6. A hygiene mat according to any of claims 1-5, characterized in that the hygiene mat is manufactured in the form of a roll.
 Incontinence is very common in the geriatric care and diapers are used to a large extent in order to protect the bed and the patient's clothes from becoming wet. Unfortunately, diapers are not reliable, they leak quite often. The problem is that it is difficult to apply the diapers satisfactorily on a patient lying in bed. When patients move the diapers are displaced resulting in frequent leakage. In order to protect the bedclothes hygiene mats are used to a large event. They are placed in the bed on top of the sheets as protection against diaper leakage. The amount of leakage occurring in this context is most often small, normally about 50 ml and seldom above 100 ml, sea diagram 1 in FIG. 12, but this is enough to necessitate an exchange of the bedclothes.
 Hygiene mats are also used in infant care. Infants having eczema from napkins are recommended to lie without napkin until the eczema has healed. The hygiene mat is also used as a protection in many other situations in healthcare, e g in emergency wards, medical centers, etc., in order to prevent body fluids or urine to contaminate furniture or other utensiles. Hygiene mats are manufactured in many sizes, the most common size is square with a surface of 60×60 cm, but much larger and also smaller dimensions occur. The most common structure comprises mainly three components; one liquid barrier layer of polyethylene film, an upper layer of non-woven, and an absorbent placed between the polyethylene film and the non-woven layer. Superabsorbents can also be contained in the absorbent in order to enhance the absorptive characteristics, especially the rewetting. The biggest problem with these types of hygiene mats is that they lack stability and therefor are easily wrinkled and creased and do not lie still in bed. This is associated with much uncomfortness for the patient/user, who may have to lie on a creased hygiene mat. It is well known in connection with healthcare that pressure wounds and bedsore occur easily, especially on immobile patients, if the bed surface is uneven, has creases or other projections.
 Absorbents, surface layers and liquid barrier layers in existing hygiene mats are all made of materials having a very poor stability.
 Especially the absorption material looses its stability completely when it has become wet. The hygiene mat wrinkles and creases itself easily in the bed and becomes unpleasant to lie on, the risk for pressure wounds and bedsore increases substantially, especially for elderly persons. This invention provides an extraordinary stable soft-stiff structure which substantially reduces the risk for wrinkling and creasing of the hygiene mat because the liquid barrier consists of expanded polymer with closed cells and very low density. Further, the stability is maintained to a large extent, even if the hygiene mat becomes wet, since the liquid barrier/stabilizing layer does not absorb any liquid. The cost of the material in the liquid barrier/stabilising layer also becoms quite low; e.g. liquid barrier/stabilising layer 1 mm thick having a density of 20 kg/m3 only weighs 20 g/m2, i.e. the same as a liquid barrier of polyethylene film being 0.022 mm thick, which is the most common thickness of hygiene mats. The absorbent layer in ordinary hygiene mats also must have an uncalled for high basis weight in order for the hygiene mat to gain at least some stability. From an absorptive point of view this is normally not necessary, since the quantities of liquid which need to be absorbed in a hygiene mat are comparatively small, see diagram 1 in FIG. 12. The basis weight of the absorbent material can therefor be reduced considerably in hygiene mats manufactured according to the invention. The hygiene mat can be provided with pressure sensitive adhesive on the outside of the liquid barrier/stabilising layer, and with this further advantages can be obtained in that it prevents the hygiene mat from sliding in bed. According to one embodiment of the invention the hygiene mat is manufactured in roll form and with rear off markings, which makes it possible to apply the pressure sensitve glue without the use of a protective cover in a simple manner, since the glue will not come into contact with itself and there is no risk of sticking. A comparison of the resistance to bending, which is described more in detail on page 7, between a hygiene mat which is described more in detail in example 1, being provided with a liquid barrier layer of polyethylene film being 0.022 mm thick and a basis weight of 20 g/m3, which is the most common liquid barrier layer on hygiene mats in the prior art embodiment, and the embodiment according to the invention with expanded polyethylene having a thickness of 1 mm and a basis weight of 20 g/m2 as a liquid barrier layer, showed that the embodiment according to the invention got 4 times as high resistance to bending in a dry condition in the lateral and in the longitudinal direction and 5 times as high resistance to bending in the longitudinal direction and 8 times higher resistance to bending in the lateral direction in wet condition with a dosage amount of 1 ml synthetic urine. Thus, the embodiment according to the invention exhibits a substantial improvement of the stability of the hygiene mat compared to the prior art embodiment of hygiene mats, especially when the hygiene mat is wet. Because the expanded polymer has a very low density, it is soft and flexible, it does not crease and it does not rustle, which is the normal behaviour of plastic films.
FIG. 1 shows a hygiene mat with the side facing the body pointing upwards in the Fig.
FIG. 2 shows a cross-section of FIG. 1 along the line A-A.
FIG. 3 shows a cross-section of a hygiene mat when the side edges have been glued or welded together.
FIG. 4 shows a hygiene mat with an absorbent consisting of several layers, wherein the side edges having been glued or welded together.
FIG. 5 shows a hygiene mat with the backside up, where the liquid barrier/stabilising layer is provided with glue or a coating increasing the friction in the form of a screen.
FIG. 6 shows a hygiene mat with the backside up, where the liquid barrier/stabilising layer is provided with glue or a coating increasing the friction in the form of strands.
FIG. 7 shows a hygiene mat with the backside up where the expanded plastic is provided with glue or a coating increasing the friction in the form of a rim around the hygiene mat.
FIG. 8 shows a hygiene mat manufactured in a roll with a tear-off perforation,
FIG. 9 shows a test specimen under pressure,
FIG. 10 shows a method for measuring resistance to bending with the aid of a scale,
FIG. 11 shows a cross-section of a hygiene mat and matress where the hygiene mat is provided with tabs wrapped in under the matress, and
FIG. 12 is a diagram showing the measured amount of urine having leaked from diapers during exchange.
 The invention relates to a hygiene mat consisting of a liquid permeable surface layer 1, FIG. 1, intended to lie adjacent to the body of a user och consisting of non-woven, e.g. manufactured from polypropylene, polyester, polyethylene, viscose or mixtures thereof or other material mixtures suitable for the intended purpose. The basis weight can vary between 5 and 150 g/m2, preferably 5-60 g/m2. These types of surface layers are common in the market of hygiene products and are thus well known for the man skilled in the art. The surface layer 1 can also be omitted if the absorptive body 2, FIG. 2, has a sufficiently high quality to be allowed to lie directly against the user. The absorption layer 2, FIG. 2, can be made of cellulose fluff, dry-formed cellulose, tissue, soft-paper, natural fibre such as cotton, in a layer 2, FIGS. 2-3, or several layers 4, FIG. 4. The total basis weight of the absorptive layer can vary between 10 and 300 g/m2, preferably 20-200 g/ml, and also comprise superabsorbents in fibre or granulate form in an amounts of 5-80% by weight of the absorptive layer. The absorptive layer can also be divided into several independent parts, see for example U.S. Pat. No. 4,892,535, or consist of slit absorbent material, see for example SE 9601302 or U.S. Pat. No. 4,560,372. The liquid barrier/stabilising layer 3 in FIGS. 2-4 is made of expanded polymers with closed cells, such as polyethylene, polypropylene, PVC, polystyrene or copolymers thereof, or other polymers suitable for the intended purpose, preferably polyethylene or polypropylene. The expanded polymer can also be made of polymer materials giving a water vapour permeability of between 900 and 10 000 g/m2/24 h, preferably 1000-6000 g/m2/24 h. The liquid barrier/stabilising layer thickness is between 0.2 and 2.5 mm with a density of between 5 and 60 g/m3, preferably 5-40 kg/m3 land a specific resistance to bending of between 0.05 and 3.5 g/cm.
 The liquid barrier/stabilising layer can also be provided with a thin plastic film of for example polyethylene, polypropylene or any other suitable polymer. The liquid barrier/stabilising layer 3, FIGS. 2-4, can also be provided with a self-adhering adhesive on the outside, e.g. of the type used in “post it” yellow note pads from 3M or other types of pressure sensitive glees, in order to increase the friction against the bedclothes, so that the hygiene mat stayes in place and does not slide. Also other types of non-sticky materials increasing friction can advantageously be applied on the outside of the liquid barrier/stabilising layer. They ca=for example consist of hotmelt with friction increasing additives of e.g. silica, chalk, etc., or cold glue of different types such as dispersion of ethylene vinyl acetate or other friction increasing additives. These types of friction increasing additives are well known to the man skilled in the art.
 The glue can for example be placed all over the surface or as a screen 6, FIG. 5, as strands 7, FIG. 6, or only around the edges 8, FIG. 7, or only on two edges or in another array well suited for the intended function. The glue may be provided with a cover layer made of paper, plastic or silicone covered paper, which is removed before use. The hygiene mats can also be supplied in the form of a roll with a perforation 9, FIG. 8, for tearing off individual hygiene mats. This embodiment is very well suited when the glue is nor provided with a cover layer. In one embodiment of the hygiene mat the absorbation layer 2, FIG. 3; or 4, FIG. 4, is wrapped between the surface layer 1 and the liquid barrier/stabilising layer 3, which layers have been joined together all around the hygiene mat in an edge 5 by gluing, hear sealing or a combination thereof. All layers a the hygiene mats can be completely or partly joined together with glue. The hygiene mats can be square, rectangular or shaped as a parallelogram or with any other for adapted for the intended function, such as circular, eliptic, preferably square, rectangular or as a parallelogram with a dimension of between 400×400 mm-1000×1000 mm in the square formation or between 300×400-1000×1200 mm in the rectangular or parallelogram formation. Hygiene mats can also be provided with tabs of suitable material, such as non-woven, plastic film, expanded polymers, paper or for the purpose well suited materials, intended to be wrapped under the bed matress. The width of the tabs is mainly the same as the width of any of the sides in the hygiene mats with a length that makes a satisfactory wrapping under the bed matress possible.
 Description of a Testing Method for Measuring Resistance to Bending
 A test body with the dimension 5×5 cm is cut from the test specimen which is to be tested. The test body 12 is folded double in the longitudinal direction of the test body LD or in the lateral direction TD, FIG. 9, and a 1.5 kg weight 11 is placed on the folded test body for 2 minutes. The test body is then placed on the plate 13 of a scale 14, FIG. 10. An upper plate 15 having a width of at least 6 cm with legs 16 is placed so that it presses the test body 12 against the scale plate 13, which is situated at a distance of 11 mm from the upper plate 15. The pressure force is read after a waiting period of 1 minute and is a measure of the stability of the tested material. The testing is repeated in the lateral direction of the test body 12. The testing can also be performed in a wet state, the test body is then placed on a plane support, a suitable amount of testing liquid is applied with a pipette in the centre of the test specimen and at the same time a timer is started. After 1 min absorption time inclusive of the application time for the liquid the resistance to bending in TD and LD is measured as defined above. The result from the measurements is presented as the mean value of the measurements converted into g/cm with two decimals.
 A hygiene mat according to FIG. 2 with a square dimension of 500×600=a consisting of an upper side 1 of non-woven situated adjacent to the body of the user having a basis weight of 23 g/m2, e.g. Pellylux. PPH23 from Pellytex Germany, laminated with a dry formed cellulose 2 with a grammage of 20 g/m2 and a thickness of 1 mm and density of 20 cg/m2, Fawolen FW 20, Fagerdala World Foam, Sweden. The specific resistance to bending in a dry state in this embodiment of the invention is in the longitudinal direction 0.87 g/cm, in the lateral direction 1.2 g/cm. In a wet state with a dosage of 1.0 ml synthetic urine 0.29 g/cm in the longitudinal direction and 0.655 g/cm in the lateral direction.
 A hygiene mat, which is shown in cross-section in FIG. 2, where the surface layer 1 consists of non-woven spunlaid polypropan with a basis weight of 20 g/m2, e.g. Fiberweb Sweden Ho 020. The absorbent 4 consists of 4 tissue layers each having a basis weight of 18 g/m2, e.g. Finess AB Sverige B18, and a liquid barrier/stabilising layer 3 consisting of expanded polyethylene with a basis weight of 18 g/m2, a thickness of 0.6 mm and a density of 30 kg/m3, Pawolen FW 30, 0.6 mm, Fagerdala World Foam AB Sweden. The absorbent 4 is rectangular with a dimension of 550×750 mm and the surface layer 1 of non-woven, and the expanded polyethylene 3 are also rectangular with a dimension of 600×800 mm. The surface layer 1 and the liquid barrier/stabilising layer 3 are put together all the way around the hygiene mat in a rim having a width of about 25 mm with hotmelt, e.g. Swift E40-161.
 A hygiene mat according to FIG. 5, wherein the liquid barrier/stabilising layer 3 made of expanded polyethene with a basis weight of 20 g/m3, a thickness of 1.0 mm and a density of 20 kg/m2, Fawolen FW 20, 1.0 mm, Fagerdala world Foam AB, Sweden, is provided with an adhesive increasing the friction, e.g. Paltomal 1710, from Svenska Lim or MSA 36 or 48 from 3M, which is applied in the form of strands 7 having a width of 1 cm and a mutual distance of 10 cm.