FR2781679A1 - NEW WATERPROOF HYDROCELLULAR DRESSING AND USE OF A HYDROCOLLOID ADHESIVE MASS - Google Patents

Abstract

The invention concerns a sealed hydrocellular dressing comprising: (a) a support (3) permeable to water vapour, but impermeable to water and bacteria; (b) an adhesive layer (2) fixed by one of its surfaces on said support (3) surface; and an absorbent hydrophilic foam (1) fixed on the other surface of said adhesive layer (2), said foam (1) having smaller dimensions than said adhesive layer (2) such that said adhesive layer (2) form a peripheral outline (4) around said foam (1) in contact with the wound, said adhesive outline (4) enabling to fix the dressing on the skin but not on the wound, said adhesive layer (2) being a hydrocolloidal adhesive mass which acts as a sealing joint to avoid leakage. The invention also concerns the use of said hydrocolloidal adhesive mass in a hydrocellular dressing.

Description

NEW WATERPROOF HYDROCELLULAR DRESSING AND

  USE OF A HYDROCOLLOID ADHESIVE MASS

  FIELD OF THE INVENTION The subject of the present invention is a new hydrocellular dressing which makes it possible to eliminate the problems of migration and leakage of the bodily fluids absorbed by the absorbent hydrophilic foam or in contact with the wound. The invention relates more particularly to the production of such a hydrocellular dressing for the treatment of exudative wounds, bedsores and burns. It also relates to the use of a hydrocolloid adhesive mass for the production of such a dressing. i5 Prior Art The primary role of a dressing is to absorb body fluids such as exudates and biological fluids excreted by the wound while maintaining a moist environment in contact with the wound.

  favorable to the healing process.

  The dressing must therefore try to maintain the longest possible absorption potential in order to limit as much as possible the renewal of dressings which are traumatic for the patient, for the quality of healing (tearing of newly formed tissue,

  bleeding etc.) and which are costly to the community.

  With this in mind, so-called "hydrocellular" dressings have been developed in which a hydrophilic absorbent foam, generally made of polyurethane, is in contact with the wound, and absorbs and

stores exudates.

  Such products are for example marketed under the

  names TIELLE, ASKINA and ALLEVYN Adhesive respec-

  by JOHNSON & JOHNSON, B. BRAUN

BIOTROL S.A. and SMITH & NEPHEW.

  If such products have remarkable absorption properties, they nevertheless present a non-negligible problem in terms of the migration and storage of the exudates which saturate the foam.

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  absorbent. Physiological fluids are quickly leaked out of the foam, either under the effect of the weight of the liquids if the dressing is not horizontal, or by compression, for example under the weight of the patient or a of its members. However, these phenomena have harmful effects both in terms of

  wound only on the holding of the dressing.

  These leaks of liquids can thus reach the tissues adjacent to the wound and constitute elements favorable to the degradation of healthy perilesional tissues with in particular phenomena of maceration and risks of secondary infection. There is also a possible drying of the wound which will be unfavorable to the healing process and which will make the change of the dressing very painful. There may also be problems with contamination of caregivers if patients are

  example with AIDS or hepatitis.

  Finally, the appearance of leaks generally results in a loss of adhesion of the peripheral adhesive which keeps the dressing on the skin, which means that the latter has to be replaced more frequently or the part in contact with the wound must also be adhesive. One of the objectives in wound healing is to minimize these renewals which become traumatic for the patient, in particular when the wound dries up and

  the entire dressing, including the wound surface, is adhesive.

  Depending on the case, there is also a migration of biological liquids towards the support of the dressing, which causes the appearance of spots, halos, or even an appearance of humidity of the latter which makes one believe in leaks. In addition to the unsightly appearance of such a dressing for the patient, such a phenomenon disturbs psychologically or sometimes panics the latter. In addition, it has also been found that the nursing staff then tend to change the dressing, when in fact this is not justified. Reducing the frequency of dressing changes is a criterion

  fundamental to promote healing.

  In order to solve these leakage problems, it is proposed in patent application WO-A-97/42917 to enclose the absorbent material between a layer in contact with the wound and an occlusive layer by sealing

  part of the absorbent region.

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  Similarly, the ALLEVYN Adhesive dressing encloses the

  absorbent foam between an adhesive knitted fabric and a support film.

  Besides the fact that this solution leads to the production of a complex dressing, therefore more difficult and more expensive to produce, it does not make it possible to solve all the problems, in particular those linked to the migration of biological liquids to the support at the same time. axially (ie in the direction perpendicular to the plane of the dressing) and transversely. OBJECT OF THE INVENTION In the field of hydrocellular dressings, it would therefore be desirable to have a new technical solution making it possible to produce a simple dressing, fixed by adhesion to the skin and not to the wound and which prevents leakage and migration. axial and transverse

biological fluids.

  OBJECT OF THE INVENTION According to the present invention, it is proposed to provide such a hydrocellular dressing which comprises: ò a support 3 permeable to water vapor, but impermeable to liquids, and mainly to water, and to microorganisms, and in particular to bacteria, * an adhesive layer 2 fixed by one of its faces over the entire surface of said support 3, and * a hydrophilic absorbent foam 1 fixed on the other face of said adhesive layer 2, said foam 1 being of dimensions smaller than those of said adhesive layer 2 so that said adhesive layer 2 forms a peripheral periphery 4 around said foam 1 in contact with the wound, said adhesive periphery 4 making it possible to fix the dressing on the skin but not on the wound, said dressing being characterized in that said adhesive layer 2 is

a hydrocolloid adhesive mass.

  According to another aspect of the invention, the use of a hydrocolloid adhesive mass is recommended in a hydrocellular dressing, said use being characterized in that a hydrocolloid adhesive mass is used as a seal, for avoid the leakage of biological fluids or their migrations axially

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  and transversely out of the absorbent hydrophilic foam.

Brief description of the drawings

  In the accompanying drawings, FIGS. 1A and 1B schematically represent the structure of a dressing according to the invention which consists of: * a support (3) consisting of a film in FIG. 1B or of a film-foam complex in FIG. 1A, * of an adhesive layer (2) fixed either on one of the sides of the film (FIG. 1B), or on the foam of the film-foam complex (FIG. 1A) and of a hydrophilic absorbent foam (1) in contact with the wound; * Figures 2A to 2F schematically represent the structures of the various dressings numbered 1 to 7 tested as part of the sealing experiments; and, e Figure 3 schematically shows a front view of the device

  used to carry out the sealing experiments.

  Detailed description of the invention

Absorbent foam -

  The new waterproof dressing according to the invention is a dressing of the so-called hydrocellular type, that is to say that the absorption of biological liquids is carried out using a hydrophilic absorbent foam in contact with the wound. Such a foam is said to be hydrophilic because it has the capacity to absorb liquids and store them in quantities

  important. This type of foam is well known to those skilled in the art.

  It will thus be possible to use foams based on polyacrylates such as those described in patent application WO-A-97/17397 and polyurethane foams which are generally the most used because of their safety and their properties. 'absorption and integrity. Such foams are for example sold under the name HYDRASORB. Most of these foams are open cell, are capable of absorbing between 8 and 40 times their weight in liquids and are made from prepolymers such as those sold under the name HYPOL Hydrogel by the company

GRACE.

  In the context of the present invention, the

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  foams sold under the name AMREL, and all

  particularly the reference L 00562, by the company RYNEL.

-Support-

  The support (3) of the dressing must be impermeable to water and bacteria and permeable to water vapor. In the context of the present invention, a support will be used which has a permeability to water vapor of between 1500 g / m2 / 24 h and 10000 g / m2 / 24 h. Such a support is well known to those skilled in the art and is commonly used in the production of dressings for the treatment of wounds. It can be in the form of a film with a thickness of 5 to 150 μm or a

  nonwoven or foam having a thickness of 10 to 500 / m.

  In addition to these two essential properties for good healing -

  tion of the wound, the choice of support will be made according to additional required properties (elasticity, aesthetics, conformability, color, transparency or thickness), for example according to the place of use

  (hospital or home) or the application site on the body.

  Among the supports based on synthetic or natural materials generally used by those skilled in the art, mention may thus be made of polyethylene, polyurethane, PVC foams, on the one hand, and nonwovens

  made of polypropylene, polyamide, polyester and the like, on the other hand.

  Among the films which can be used as a support, there may be mentioned in particular polyurethane films, low density polyethylene films such as for example those sold by the company SOPAL, films based on a polyether-polyester thermoplastic copolymer such as for example the products marketed under the brand

  HYTREL by the company DUPONT DE NEMOURS.

  In the context of the present invention, polyurethane films will be preferred, such as for example the products sold by the company SMITH & NEPHEW under the reference "LASSO" or under the

  name ESTANE by the company BF GOODRICH and all individuals

  polyurethane films made from polyurethane

  marketed under the name UCECOAT by the company UCB.

  Among the foams, preference is given to non-absorbent polyurethane foams with mainly closed cells which have a high density such as, for example, MEDIFIX products.

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4003 or 4005.

  It is also possible to use as support 3 complexes produced on the basis of a polyurethane foam and a polyurethane film or

  complexes made from polyurethane film and a nonwoven.

  In the context of the present invention, the complex which is formed by a non-absorbent foam mainly with open cells permeable to water vapor and a waterproof polyurethane film, such as the PLASTDERM product of the

  GRIFFINE company, and which has a thickness of the order of 250 to 350 jzm.

l0 - Adhesive layer -

  ......................................... DTD: The adhesive layer 2, which ensures the sealing of the dressing

  hydrocellular according to the invention is a hydrocolloid adhesive mass.

  Thanks to its adhesive properties, the latter ensures the superposition of the various components of the dressing, namely the support 3 and the foam 1, which allows the production of a dressing very simple to manufacture and therefore

cheap.

  In addition, thanks to its adhesion properties and its ability to function as a seal, the hydrocolloid adhesive mass also eliminates the problems of detachment of the dressing. It makes it possible to fix the latter only thanks to the adhesive periphery 4, which surrounds the foam 1 in contact with the wound, and thus avoids using an adhesive in

  contact with the wound, to maintain the dressing.

  Finally, we see that the hydrocolloid adhesive mass prevents the axial and transverse migration of physiological fluids

towards and under the support.

  In addition, the support (3) can be coated with much larger quantities of hydrocolloid adhesive mass compared to the conventional adhesives used. We can thus obtain by coating an adhesive layer having a grammage between 150 and 500 g / m2, and

  preferably between 250 and 400 g / m2.

  This is not possible with conventional adhesives which are generally deposited by coating according to a grammage of between 10 and 150 g / m2. Indeed, with adhesives in the form of a mass in solution in a solvent system or in the form of an aqueous dispersion, we get

7 2781679

  comes up against cost and disposal problems for such weights

  solvents or water by drying.

  In addition, the large thickness of these adhesives will cause cohesive ruptures and we will leave traces of adhesives on the skin or wound during dressing changes, which is unacceptable.

  Finally, by using a large thickness of hydro-

  adhesive colloid, it is easier to obtain a perfectly homogeneous and smooth surface, which avoids the appearance of channels in the adhesive layer which, in contact with biological fluids, will promote and

  o to speed up flow and leaks.

  Hydrocolloid adhesive masses are well known to those skilled in the art. They are described in particular in published patent applications EP-A-0130061, EP-A-0092999, WO-A-98/10801 and the

Patent issued US-A-3972328.

  These hydrocolloid adhesive masses are mainly formed

  addition of an adhesive matrix, generally consisting (i) of at least one elastomer chosen from polymers such as polyisobutylenes or poly (styrene-olefin-styrene) block copolymers, combined or not with agents making it possible to improve adhesion such as tackifying resins called tackifiers, plasticizers such as polybutenes or plasticizing oils, or to agents making it possible to improve cohesion such as butyl rubber and the like, and (ii) one or more hydrocolloids. Such adhesive matrices are thus defined in "Advances in Pressure Sensitive Adhesive Technology-2" published by Donatas Satas in April 1995 in chapter 7 "Wound Dressings" pages 158 to 171. Reference may also be made in this regard to the documents from the state of the art mentioned above, for the definitions of all the compounds used in these formulations and their respective proportions in the adhesive matrix. Said formulations are produced in a conventional manner by a person skilled in the art so as to obtain the desired adhesive and cohesive properties by adopting the amount of each compound. In the context of the production of hydrocolloid adhesive masses according to the invention, the hydrocolloid substances are

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  compounds commonly used by those skilled in the art and known for their ability to absorb aqueous or hydrophilic liquids, in particular biological liquids. As suitable hydrocolloids, mention may, for example, be made of polyvinyl alcohol, gelatin, pectin, sodium alginates, natural vegetable gums (in particular carob gum, Karaya gum, guar gum, gum arabic), the

  cellulose derivatives (especially hydroxyethylcelluloses, hydroxy-

  propylcelluloses, carboxymethylcelluloses and their alkali or alkaline earth metal salts, such as sodium or calcium). We can use these

  o0 hydrocolloids alone or in combination.

  In the context of the present invention, the alkali metal salts of carboxymethylcellulose are preferred; especially sodium CMC. Compounds to improve the absorption capacity or kinetics can be incorporated into the formulation if necessary.

the hydrocolloid adhesive mass.

  According to a currently preferred embodiment, the hydrocolloid adhesive mass also contains an acrylate polymer having a glass transition temperature (Tg) of less than −20 C. Such a hydrocolloid adhesive mass is thus described in the published application WO-A-98 / 10801, and has excellent properties of both adhesion and absorption, but also of cohesion. However, this cohesion property is advantageous in the context of the production of waterproof hydrocellular dressings to avoid, under the effect of a pressure, for example under the weight of the patient, the axial and transverse migration of the biological liquids in the hydrocolloid adhesive mass, even a rejection of biological fluids

  that it can absorb, which would then cause leaks.

  Best mode The best mode of implementing the invention consists in making a hydrocellular dressing which comprises * a support 3 which is a complex (foam-film) formed of a polyurethane foam with open cells, vapor permeable to water, and a polyurethane film impermeable to water and bacteria * a hydrocolloid adhesive mass 2 comprising: (a) 10 to 35 parts by weight of a block copolymer

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  poly (styrene-olefin-styrene), especially a poly-

  (styrene-isoprene-styrene), (b) 20 to 50 parts by weight of a tackifying resin, (c) 2 to 15 parts by weight of an acrylate polymer having a glass transition temperature below -20 C, ( d) 2 to 25 parts by weight of a plasticizer, in particular a plasticizing oil, (e) 20 to 50 parts by weight of a hydrocolloid, and (f) 0.1 to 2 parts by weight of at least one agent antioxidant; and,

  To an absorbent hydrophilic foam 1 made of polyurethane.

  The dressings according to the invention are manufactured according to techniques well known to those skilled in the art. The hydrocolloid adhesive mass 2 is coated on a support 3 with the desired grammage, according to techniques known to those skilled in the art, according to a process in the solvent phase or preferably according to a hot-melt process at a temperature generally between 110 and 160 C. Then the foam 1 is cut and the latter is placed on the support 3 covered with the adhesive layer 2 and the dressing is cut to the desired dimensions. The hydrocellular dressings according to the invention can be in any geometric, square, rectangular, circular or oval shape. Likewise, their size can be arbitrary and will be adapted as a function of the surface of the damaged portion of skin that is desired.

treat or protect.

  In practice, the surface, which comes into contact with the wound and the skin, may be covered with a peelable protective layer or film before using the dressing. The assembly thus formed may itself be packaged in a waterproof protection produced for example at

  using polyethylene-aluminum, polyester / polyethylene complexes

aluminum or in blisters.

  The hydrocellular dressings according to the invention are useful for the treatment of epidermal lesions, in particular chronic, deep and acute. They will thus be used for the treatment of wounds

exudative, bedsores and burns.

  Other advantages and characteristics of the invention will be

  better understood on reading the following description of examples of

  realization and comparative tests against products today

  and various other dressings.

  Of course, all of these elements are in no way limiting but are given by way of illustration. Tests In order to highlight the advantages and performances of the dressings according to the invention, leakage tests were carried out with the device illustrated in FIG. 3. These measurements are carried out according to the

o10 following protocol.

  One side of the dressings to be tested is cut so as to easily access the absorbent foam 31. The dressing thus cut is fixed by its adhesive face 34 on a steel sheet 32 which is placed vertically. The dressing is fixed in such a way that the cut side then forms the upper part of the dressing on the steel sheet,

as shown in figure 3.

  The absorbent foam 31 is then saturated, by the cut side where it is accessible, with a solution of physiological serum or dextran, which is introduced according to arrow 33, for example using a

Pear.

  In the present test, either 10 or 20 ml of physiological saline (aqueous sodium chloride solution at 9 g / l) or 20 ml of dextran solution, the viscosity of which is closer to that of the exudates, was used. 0.6% w / v dextran and 0.9% w / v chloride

sodium.

  The test is carried out at 23 C. The behavior of the dressing thus saturated is observed over time. There may or may not be (i) the appearance of spots or halos on the support, (ii) detachment of the dressing, (iii) leaks or oozing from the edges, and (iv)

the appearance of moisture.

  Unless otherwise indicated, in all the experiments carried out, the peripheral adhesive has a width of 2 cm. The

  dressings numbered 1 to 7 below were tested.

  Dressing 1 FIG. 2A schematically represents the structure of the dressing 2781679 sold by the company JOHNSON & JOHNSON under the name TIELLE &. It consists of a hydrophilic polyurethane foam in the center, a nonwoven 8, a layer of adhesive

  polyurethane 2a and a polyurethane foam support 3a.

  Dressing 2 Figure 2B schematically represents the structure of the dressing sold by the company SMITH & NEPHEW under the name ALLEVYN Adhesive. It consists of a hydrophilic polyurethane foam lb enclosed between a microperforated adhesive 5 + 6 film in contact with the skin, and a film support

polyurethane 3b.

  Dressing 3 FIG. 2C schematically represents the structure of the dressing sold by the company B. BRAUN BIOTROL S.A. under the name ASKINA. It consists of an adhesive knitted fabric 7, in contact with the wound, of a hydrophilic polyurethane foam lc and of a support of polyurethane film 3c and does not include a peripheral periphery. Dressing 4 FIG. 2D schematically represents a dressing according to the invention, which comprises a central polyurethane hydrophilic foam i sold under the reference L00562 by the company RYNEL, an adhesive layer 2 of hydrocolloid adhesive mass coated at 300 g / m2 and a support 3 formed of a polyurethane foam complex permeable to open cell water vapor / polyurethane film impermeable to bacteria and bacteria marketed by the company GRIFFINE under the

name PLASTDERM.

  Dressing 5 This dressing illustrated in FIG. 2F has a structure identical to that of FIG. 2D, but in this case, unlike dressing 4 according to the invention, layer 2f is an acrylic adhesive sold by the company NATIONAL STARCH under the name DUROTAK

coated at 45 g / m2.

  Dressing 6 Figure 2E schematically represents this dressing which is

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  composed of a central polyurethane hydrophilic foam for the commercial-

  read under the reference L00562 by the company RYNEL, an adhesive layer 2e consisting of an acrylic adhesive marketed by the company AV CHEMIE under the name POLYTEX 120 coated at 25 g / m2 and a support 3rd formed of a film polyurethane 30 µm thick made from polyurethane marketed under the

  UCECOAT name by UCB.

  Dressing 7 This dressing has a structure identical to that of FIG. 2E o but in this case the adhesive layer 2e is constituted by a polyurethane adhesive coated at 25 g / m2 sold by the company BAYER AG

under the name LEVAGEL.

  The dressing 4 according to the invention and the non-marketed dressings 5, 6 and 7 are produced according to techniques well known to those skilled in the art. The procedure followed comprising coating on the support 3, 3e or 3f, complex or film, of the adhesive or of the hydrocolloid adhesive mass 2, 2e or 2f; cutting the foam 1, the or If and placing the latter on the support 3, 3e or 3f covered with the adhesive layer 2, 2e or 2f; and cutting the dressing

to the desired dimensions.

Results -

  ....... DTD: The results of the leak tests are as follows.

* Dressing 1

  20 ml of physiological saline are used.

  There is a swelling of the foam which absorbs the liquid.

  Leaks appear at the angle formed by the foam la and the

  polyurethane adhesive layer 2a.

  On contact with liquid, the adhesive layer becomes hydrated and loses its properties

  adhesion, which leads to detachment of the product.

a Dressing 2

  20 ml of dextran solution are used.

  There is no leakage from the edges. The structure of the dressing which

  fully encloses the foam to prevent leakage.

  However, there is the appearance of halos and spots on the support and an impression of humidity which illustrate the axial and transverse migration.

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some cash.

* Dressing 3

  20 ml of dextran solution are used.

  The dressing immediately leaks from the edges in the absence of a peripheral periphery around the foam. Dressing 4

  a) 20 ml of physiological saline are used.

No leaks or detachment.

No spots or halos.

  There is therefore no migration of the liquid axially or transversely.

  We tested under the same conditions a bandage whose peripheral periphery is 1 cm instead of 2 cm which is the minimum width, to avoid leaks with a conventional peripheral adhesive, which man uses.

art.

  Likewise, no leakage, no stain and no separation appear in this case with an adhesive layer (2) which is a hydrocolloid adhesive mass.

  b) 20 ml of dextran solution are used.

  We find results identical to those obtained with 20 ml of serum

physiological.

  c) The same experiment was carried out as in point a) above, at 37 C with

  a solution of 20 ml of physiological saline.

We find an identical result.

  * Dressing 5 We used either 10 ml of physiological saline or a solution of 20 ml

dextran.

  In both cases, a wet appearance of the support 3f appears and

  appearance of spots and halos.

  We observe a seepage at the level of the foam of the film-complex

foam forming the support 3f.

  In this case, the physiological saline or the dextran solution diffuses by capillarity through the acrylic adhesive 2f and moistens the open cell foam of the complex. The transverse migration of the liquid in said open cell foam causes seepage at the level of the foam

support 3f.

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  We can notice that the similar product (ie dressing 4), in which layer 2 is a hydrocolloid adhesive mass, tested with saturation of foam 1 by means of 20 ml of physiological saline (double that in the case of dressing 5 ), does not exhibit any of these annoying phenomena, even with a periphery of only 1 cm. * Dressing 6

  We proceed as indicated for dressing 5.

  In each case, leaks appear.

  0o The adhesive used hydrates fairly quickly and peels off due to leaks

  at the foam intersection the adhesive layer 2e.

  We find the same phenomena as with dressing 1.

  * Dressing 7 We proceed as indicated for dressing 5. We observe the same

  phenomena as in the case of dressing 6 above.

  From all of these results come the following conclusions. Dressings without an adhesive border such as ASKINA (dressing 3) are unable to avoid significant leakage of liquids

as soon as the foam swells.

  A dressing with peripheral adhesive such as TIELLE (dressing 1) and which has a layer 2a of polyurethane adhesive also leaks and eventually peels off due to hydration in the direction

transverse of the adhesive.

  Likewise for dressings with a structure identical to those of the invention but whose adhesive layer 2e and 2f is not a hydrocolloid adhesive mass, none of the three adhesives tested, polyurethane (dressing 6), acrylic supplied by a solvent system ( dressing 5) or acrylic provided by an aqueous emulsion (dressing 7) does not give

satisfactory results.

  If a product such as ALLEVYN Adhesive prevents leaks by enclosing the absorbent foam lb between the support 3b and an adhesive knit 5 + 6, on the other hand, in the absence of an additional layer between the support film and the foam, liquid migration and appearance of spots and halos. In addition, the production of a dressing of this type

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  is complex and the product obtained is expensive, thicker and therefore less

  conformable and adapts less well to different parts of the body.

  Only the dressings according to the invention, which comprise an adhesive layer 2, which is a hydrocolloid adhesive foam, make it possible to obtain an optimal product in terms of sealing, appearance and adhesion. Positive results are obtained even when the peripheral periphery 4 in contact with the skin has a width of 1 cm. An optimal result is obtained whatever the nature of the support 3 foam-film complex or film alone. Only the hydrocolloid adhesive mass prevents leaks and acts as a seal between the foam and the support and seems to prevent the axial and transverse migration of liquids, unlike the tested adhesives which do not act as a seal and s '' hydrate quickly axially and transversely, which causes the dressing to come off or the appearance of moisture, stain

  or oozing depending on the nature of the support.

  These excellent results are still valid at 37 ° C, where one might have feared problems due to phenomena of loss of cohesion or degradation, or even of properties different from the mass.

  hydrocolloid adhesive at a higher temperature.

  In addition, the dressings according to the invention are simple to manufacture and are adhesive only on the skin and not on the wound and its peripheries, which avoids the problems which may appear during the renewal with an adhesive dressing on all of its surface such as bleeding, tearing of newly formed tissue, etc. In conclusion, all of these observations and the advantages which ensue clearly and clearly demonstrate that the use of a hydrocolloid adhesive mass plays a role of seal and makes it possible to control the migration of biological fluids and illustrate the positive consequences which result therefrom for the production of a waterproof hydrocellular dressing intended for the treatment of exudative wounds,

bedsores and burns.

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Claims (7)

  1. Hydrocellular wound dressing, which comprises a support (3) permeable to water vapor, but impermeable to water and bacteria, * an adhesive layer (2) fixed by one of its faces over the whole of the surface of said support (3), and * an absorbent hydrophilic foam (1) fixed on the other face of said adhesive layer (2), said foam (1) being of dimensions smaller than those of said adhesive layer (2) of so that said adhesive layer (2) forms a peripheral periphery (4) around said foam (1) in contact with the wound, said adhesive periphery (4) making it possible to fix the dressing on the skin but not on the wound, said dressing being characterized in that said adhesive layer (2) is a hydrocolloid adhesive mass.   2. hydrocellular dressing according to claim 1, characterized in that said absorbent hydrophilic foam (1) is a foam hydrophilic polyurethane.   3. Hydrocellular dressing according to one of claims 1 or   2, characterized in that the support (3) is a polyurethane film.   4. Hydrocellular dressing according to one of claims 1 or   2, characterized in that the support (3) is a foam-film complex consisting of a non-absorbent polyurethane foam mainly with open cells permeable to water vapor and of a polyurethane film   impermeable to water and bacteria.   5. Hydrocellular dressing according to any one of the claims.   cations 1 to 4, characterized in that the hydrocolloid adhesive foam comprises: (a) 10 to 35 parts by weight of a block copolymer   poly (styrene-olefin-styrene), in particular poly (styrene-   isoprene-styrene), (b) 20 to 50 parts by weight of a tackifying resin, (c) 2 to 15 parts by weight of an acrylate polymer having 17 2781679   a glass transition temperature below -20 C, (d) 2 to 25 parts by weight of a plasticizer, in particular of a plasticizing oil, (e) 20 to 50 parts by weight of a hydrocolloid, and   (t) 0.1 to 2 parts by weight of at least one antioxidant.   6. Hydrocellular dressing according to any one of the claims.   cations 1 to 5, characterized in that the adhesive layer (2) has a grammage between 150 and 500 g / m2, preferably a grammage between 250 and 400 g / m2.   7. Hydrocellular dressing according to any one of the claims   cations 1 to 6, characterized in that the face of the dressing coming into contact   with the skin and the wound is covered with a protective layer adherable peelable before use.