SE447205B - Absorbent product with material layers of different pore sizes - Google Patents

Abstract

Absorbent products, such as diaper or bandaging, which include one layer (1) of absorbent material, such as CMC laminate, and at least two layers (2, 3) of reticulate foam plastic with capillary pores. The layers (2, 3) of foam plastic have different pore sizes and are arranged with successively larger pore sizes out from the absorbent layer (1). The layers of foam plastic are preferably made of polyurethane with a ppi range of 10-100, preferably 60-100. The ppi count in the adjacent layer of foam plastic differs by at least 10 parts, preferably at least 20 parts. A dispersive absorbent layer can be positioned between the layer of absorbent material and the innermost layer of foam plastic and the product's outer side can also be coated with gauze fabric. The innermost layer (2) of foam plastic can be impregnated with a bioactive material, such as a biocide.<IMAGE>

Description

A further object of the invention is to provide an absorbent product which counteracts unpleasant odor and infection from the absorbent liquid by treating it with deodorizing agents or biocides.

The above and other objects and advantages of the invention are achieved by means of an absorbent product with an absorbent material layer for absorbing secreted body fluids, which product is characterized in that on one side of the absorbent material layer there are at least two layers of reticular foam acting as capillaries pores, the foam plastic layers having different average pore sizes and being arranged with successively increasing pore size, calculated from the absorbent material layer.

Further features of the invention appear from the following dependent claims.

In the following, a more detailed description will be given of the materials and components used for the absorbent product according to the invention.

The absorbent material layer can in principle consist of any liquid-absorbent material.

The invention thus involves the use of all the absorbent materials used in conventional absorbent products, such as the above-mentioned layer or flake-shaped cellulose, cotton, etc. Mention may also be made of highly absorbent hydrophilic polymers having an absorbency of about 100-1200 ml / g, which are known under the names "Superslurper", "Stasorb" and "H-Span" and which consist of graft copolymers of starch and starch derivatives and vinyl monomers, respectively. , such as acrylonitrile, methyl methacrylate and acrylamide. A preferred absorbent material is cellulose derivatives, especially carboxymethylcellulose, in sheet form. It is particularly preferred that the absorbent material layer be in the form of a sheet consisting of a plurality of laminated layers.

Den rkuxnp.l, n; _; l: som víiJjr-s fö; .mvIin-Ininq wants salary-- 10 15 20 25 30 35 _ .. _ .. ff _... o., ..... _._ r ___. 447 205 3 the present invention may be of a known type. is thus not limited to foams of any particular type or material, other than the condition that the foam is reticular, by which is meant a foam having a three-dimensional structure which defines numerous individual cells in which most or all of the cell wall membranes defining the cells, are removed so that only the skeleton of the three-dimensional structure remains. Pores here refer to continuous, open channels in the foam plastic. A further condition is that the pores must act as capillaries, ie the liquid to be absorbed must be absorbed into the pores by capillary action.

Normally a foam is used which does not or at least substantially does not swell on contact with aqueous solutions, but the invention does not preclude use with foams with special properties, such as absorbent and / or swellable foams for special purposes. Hydrophilic foams are also encompassed by the invention. Especially in cases where the foam product according to the invention is intended for biological use, such as absorption of exudate from liquid wounds, it is suitable to use specially purified foam, ie foam of standard quality which by chemical purification is freed from soluble constituents, which can have a polluting effect. in biological use.

The foams of the invention have a porosity of about 10-100 ppi (pores per inch), which corresponds to a pore size of about 0.25-2.5 mm in diameter. A general condition is that the different foam plastic layers must have different pore sizes, ie the pores of the foam plastic layers have an inwardly decreasing average diameter inwards, seen from the absorbent material layer (increasing ppi value). Briefly, this can be expressed so that an inner foam layer should have a higher ppi value (smaller pore diameter) than an adjacent outer foam layer. Considering that the ppi value of a commercial foam layer 447 205 _. _- .. .v- 10 15 20 25 30 35 4 generally varies: LO units around the specified ppi value, it is preferred that an inner foam layer has a ppi value which by at least 10 units exceeds the ppi value of the adjacent , outer foam layer.

It is particularly preferred that an inner foam layer has a ppi value which, by at least 20 units, exceeds the ppi value of the adjacent outer foam layer. This ensures that the pores of the inner foam layer have a smaller diameter than that of the adjacent outer foam layer.

Regarding the thickness of the foam plastic layers, it applies that each layer has a thickness of about 0.5-4 mm, preferably about 1.5-3 mm. It is preferred to keep the thickness of the foam plastic layers as low as possible in order to thereby reduce the overall thickness of the absorbent product. Although the invention is not bonded to foam of a particular material, a particularly preferred type of foam in the invention is polyurethane, especially polyester or polyether based polyurethane.

Polyester-based polyurethane foam plastic is particularly preferred, as it enables a homogeneous and well-defined pore size, which is a desirable feature of the invention.

Because the pores of foam plastic in the invention have capillary dimensions and furthermore the foam plastic layers are arranged with decreasing pore size, seen in the direction of the absorbent material layer, a strong liquid-absorbing effect in the direction of the absorbent material layer is achieved, while on the other hand the absorbed liquid has no tendency to migrate. in the opposite direction. This so-called valve action is a characteristic feature of the invention, which is achieved by the special arrangement of the foam plastic layers, which is illustrated by the following exemplary embodiments, in which examples are included with examples with the foam plastic layers arranged in opposite order.

As a further advantage of the invention, the inner foam layer arranged on the absorbent material layer can be impregnated with a biologically active substance, such as a biocide or a deodorizing agent, in order thereby to counteract bacteria and localizing substances.

By means of the invention it is thus possible to quickly and efficiently absorb liquid from an underlying surface, such as a wound surface, and partly to prevent the absorbed liquid from returning to the original surface and also to prevent bacterial growth in the absorbed liquid or for bacteria to penetrate into the underlying surface. The impregnation of the foam plastic layer with the biologically active substance, such as a biocide, can thus be said to act as a bactericidal barrier against bacterial penetration into the underlying surface. An example of a biocidal or disinfectant is iodine in iodophor form.

A further improvement of the absorbent product of the present invention is obtained by incorporating in the absorbent material layer, between the absorbent material and the innermost foam layer, a dispersing absorbent layer.

This is preferably a non-woven material. The openings of the spreading absorption layer have an average diameter which is at most equal to the average pore diameter of the adjacent foam plastic layer and which is preferably smaller than this.

In addition to the above-mentioned components, the absorbent product according to the invention preferably also comprises outer layers with a perforated structure, the openings of which are larger than the pores of the outer foam plastic layer. Such an outer layer is preferably arranged so that it covers at least one of the outer surfaces of the product and then suitably the absorbent foam surface. The perforated outer layer can consist of perforated polymer foil, gauze or non-woven material, and has, among other things, the task of holding the various, ._ __._......._._....... __._.___..._ 447 205 10 lf »20 25 30 35 6 the components of the absorbent product into one unit. In addition, when such a perforated outer layer is provided on top of the absorbent foam layers, it prevents the foam from adhering to or coexisting with the underlying tissue surface when the product is an absorbent wound dressing.

To further illustrate the invention, it will be illustrated in the following with exemplary embodiments with reference to the accompanying drawings. In these, Fig. 1 shows a schematic cross-section of a conventional absorbent product and an absorption diagram for the product. Fig. 2 shows a schematic cross-section of an absorbent product according to the invention and an absorption diagram for the product. Fig. 3 shows a schematic cross-section of an absorbent product, which is not in accordance with the invention, and an absorption diagram for this product. Fig. 4 shows a schematic cross-section of another embodiment of an absorbent product according to the invention and an absorption diagram for this product. Fig. 5 shows a schematic cross-section of a further embodiment of the absorbent product according to the invention and an absorption diagram for this product.

EXAMPLE 1 In this example, the absorption of an absorbent product consisting of carboxymethylcellulose (CMC) in the form of a laminate with 10 layers was examined. The sample, like the samples in the other examples, had an area of 25 cm 2 and was subjected to a load of 1.2 g / cm 3.

The absorption of distilled water was examined and initiated by adding a starting volume of 2 drops of distilled water to the sample. A diagram of the absorbed volume as a function of time was then recorded and is shown in Fig. 1, which also shows a schematic cross-sectional view of the absorbent product in this example.

Eig l shows that the CMC laminate alone has a very slow absorption rate. EXAMPLE 2 In this example, the absorption of a product according to the invention consisting of an absorbent material layer 1 of CMC laminate with 10 layers, a foam plastic layer 2, which is arranged next to the CMC laminate layer 1 and which consists of polyvinylpyrrolidone iodine-treated polyurethane foam with a ppi value of 100, and a layer 3 of hydrophilized polyurethane foam with a ppi value of 60 arranged on top of the polyurethane foam layer 2 is shown. The basic structure of this product is shown in Fig. 2.

The absorption of the above product was examined, partly by absorption with distilled water (curve A), partly by absorption with 1% saline solution (curve B) and the result is shown in Fig. 2. To initiate the absorption, 3 drops of liquid were required to add the absorbent product.

From Fig. 2 it is clear that the construction according to the invention entails a significant increase in the absorption rate.

EXAMPLE 3 This example is a comparative example and shows the absorption of a product which is not constructed in accordance with the invention, but has the layers of reticular foam deflected, ie the foam layer with the coarser pores is arranged at the innermost side of the absorbent material layer. while the foam layer with the finer pores is arranged at the end. The basic structure of the product is shown in Fig. 3. More specifically, the product consisted of an absorbent material layer 1 of CMC laminate with 10 layers, a foam layer 3 of hydrophilized polyurethane foam with a ppi value of 60, and a foam layer 2 of polyvinylpyrrolidone iodine-treated plastic with polyurethane a ppi value of 100.

To initiate the absorption, the absorption of distilled water required the addition of 2.5 ml of liquid to the product. The absorption of distilled water and 44% of saline solution is shown by curves A and B in Fig. 3, respectively, and shows that the absorption is clearly inferior to that of the product of Example 2 and comparable to that of Example 1.

EXAMPLE 4 This example illustrates the absorption of a product similar to that of Example 2, but which is also provided with a nylon mesh 4 against the outer foam layer. The basic structure of the product is shown in Fig. 4, where the corresponding material layers have been given the same reference numerals as in previous examples.

The product's absorption of distilled water was examined. To initiate the absorption, the addition of 2 drops of liquid was required. The result of the absorption determination is shown in Fig. 4 and shows that the product has an absorption corresponding to that of the product in Example 2.

EXAMPLE 5 In this example, the absorption of an absorbent product provided with a spreading nonwoven absorbent layer 5 between the layer 1 of CMC laminate and the innermost foam layer 2 was examined.

The basic structure of the product is shown in Fig. 5, in which it is also indicated that the openings of the non-woven material have a smaller diameter than the pores of the adjacent foam plastic layer 2. Reference numerals 1-4 refer to the same material as in previous examples.

The absorption of distilled water was examined.

Initiation of absorption required the addition of 3 drops of liquid to the absorbent product.

The result of the absorption determination is shown in Fig. 5, which shows that the absorption of the product is further improved by the dispersing absorption layer 5.

Although the invention has been described above with reference to particularly preferred embodiments, it will be appreciated that various modifications may be made within the scope of the invention as defined in the appended claims.

Claims (10)

lO LS 20 25 30 35 447 205 PATENTKRAV 1. l. Absorbent product with an absorbent material layer for the absorption of secreted body fluids, characterized in that on one side of the absorbent material layer (1) there are at least two layers (2, 3) of reticular foam with capillaries acting pores, the foam plastic layers having different average pore sizes and being arranged with successively increasing pore size, calculated from the absorbent material layer (1). Absorbent product according to claim 1, characterized in that the foam plastic layers (2, 3) have different ppi values in the range 10-100, preferably 60-100. Absorbent product according to claim 1 or 2, characterized in that adjacent foam plastic layers (2, 3) have ppi values which differ by at least 10 units, the layer being arranged closest to the absorbent material layer ( l) has the higher ppi value. Absorbent product according to claim 3, n e t e c k n a d due to the fact that the ppi values differ by at least 20 units. Absorbent product according to any one of the preceding claims, characterized in that there is a spreading absorption layer (5) between the absorbent material layer (1) and the innermost foam layer (2). Absorbent product according to any one of the preceding claims, wherein the known requirements, the foam plastic layer (2), which is arranged closest to the absorbent material layer, is impregnated with a biocide. Absorbent product according to one of the preceding claims, characterized in that at least one of the outer surfaces of the products is covered by a layer with a perforated structure (4), the openings of which are larger than the pores of the outermost foam layer (3). 447 205 10 10 Absorbent product according to any one of the preceding claims, wherein the foaming requirements (2, 3) are polyurethane. Absorbent product according to one of the preceding claims, characterized in that the absorbent material layer (1) consists of laminated carboxymethylcellulose. Absorbent product according to one of the preceding claims, characterized in that the cover layer with a perforated structure (4) is chosen from perforated polymer foils, gauze and non-woven material.