LU84723A1 - ARTIFICIAL SKIN - Google Patents

Description

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The present invention relates to an artificial skin, which can be used in particular for the treatment, in humans or in animals, of burns, skin wounds, areas of skin removal for grafting or, even, for covering grafts. themselves. More particularly, the present invention relates to an artificial skin comprising two superimposed layers.

Such skins are already known from the prior art. French patents may be cited, No. 2 077 361 from PARKE DAVIS, No. 2 377 205 from BATTELLE MEMORIAL INSTITUTE and No. 2 332 863 from MASSACHUSETTS INSTITUTE OF 10 TECHNOLOGY. All these industrial property titles relate to skins comprising two layers, one of which is said to be external, constituting protection of the wound against external microorganisms while being permeable to gases and vapors, in particular the water, while the other layer, brought into contact with the wound, is spongy and alveolar. This latter layer is 15 bioresorbable in the skin according to French patent No. 2,377,205, while it is not in the two other patents cited above, the layer according to French patent No. 2,077 361 essentially having the function of serving as a receptacle for debris from exudates from the wound.

However, when preparing artificial skins according to the patents cited above, an intermediate layer of adhesive or an adhesive tape is generally used to join the two previously prepared layers independently of one another. Optionally, the layers previously prepared independently can be joined by thermoplastic fusion. All the skins thus prepared have the particular disadvantage of requiring numerous manipulations in order to obtain them. On the other hand, it turned out that certain artificial skins could not be prepared industrially in a satisfactory manner according to the processes mentioned above, because the adhesion between the two layers was not sufficient or because one of the two diapers were too fragile, taken individually, to be handled.

An object of the present invention is therefore an artificial skin which does not have the drawbacks of the skins of the prior art and which can be obtained industrially according to a simple process.

An object of the present invention is more specifically an artificial skin, the two layers of which can be obtained simultaneously.

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Another object of the present invention is an artificial skin - which has improved mechanical properties, and is therefore easy to handle.

Another object of the present invention is artificial skin which is well tolerated by humans *

Another object of the present invention is an artificial skin which allows rapid healing of the wound.

Another object of the present invention is an artificial skin which can be left on the wound for several days, thus not requiring daily renewals from medical personnel. Thus, the skin according to the present invention can be left in contact with the wound during the whole healing period ’.

More specifically, in its preferred embodiment, the object of the present invention is an easy-to-obtain artificial skin 15 whose layer applied in contact with the wound is absorbable.

It has now been found and this is what is the subject of the present invention an artificial skin, characterized in that it is obtained by the simultaneous casting, on a support, of two polymeric solutions, one on the other, which after coagulation and release of the support form two flexible and distinct layers 20 linked together.

The object of the present application will be better understood with the aid of the appended plate which illustrates schematically and without a determined scale a preferred method of industrial preparation of artificial skin according to the present invention.

25 In order to obtain an artificial skin according to the present invention with reference to FIG. 1, the procedure is as follows. The endless strip (1), generally made of polished metal, advantageously made of stainless steel, is set in motion, for example by means of the driving cylinder (2), while the other cylinders (3) serve as angular gear and allow the strip (1) 30 to have the circuit shown in Figure 1. Of course, this circuit can have another configuration. The strip (1) enters a bath (4) is hole - = - in a container (5), this so-called coagulation bath being most generally made up of water or water to which a wetting agent has been added surfactant and / or optionally a product such as acetic acid, in an amount less than 15% by weight. When the strip (1) is in motion, 4 4 • tt * 3 rolls onto the latter, thanks to flowers (6 and v7) respectively the polymer solutions (8 and 9) which must respectively constitute the two layers (10 and 11) of the artificial skin that is prepared, the flowers (6, 7) being arranged so that the layers (10, 11) obtained are arranged one on the other. More specifically, one of the flowers (6 or 7) will be arranged upstream of the other (7 or 6). This is shown schematically in an enlarged manner in FIG. 2, which is a longitudinal section of the part of the complete circuit limited by the lines in dashed lines (12 and 13), the thickness of the strip (1) not being shown in this cut. The casting machines (6 and: 10 7) are of all known types and include an elongated slot in their part closest to the strip (1), this slot being arranged perpendicular to the direction of advance of the strip (1) represented by the arrow. The spacing of the slot of each casting machine (6 and 7) can determine the thickness of the layers (10 and 11) of the polymer solutions (8 and 9) deposited on the strip. If necessary, the thickness of the layers (10 and 11) of the polymer solutions can be obtained by the spacing between the lower end of the casting machines (6 and 7) and the strip (1). The casting machines can include a doctor blade to adjust the thickness of the layers. Advantageously, the polymer solution (8) which must constitute the layer (10) of smaller thickness of the skin is first deposited on the moving strip (1), the polymer solution (9) being deposited on the layer (10). . In this case, the casting machine (6) containing the polymer solution (8) is arranged upstream of the casting machine (7) containing the polymer solution (9). The two polymer solutions (8 and 9) are deposited on the strip (1) before the latter enters the coagulation bath (4). When the two layers (10 and 11) of polymeric solution enter the bath (4) coagulation takes place. At the place where the cylinder (3 bis) is located, the assembly (14) constituted by the. two coagulated layers (10 and 11) detaches from the strip (1) and is wrapped around the roller (15) as indicated by the arrow. Thus, the artificial skin is obtained and, in general, the thicknesses of the two layers (10 and 11) constituting the assembly (14) are less than those of the layers (10 and 11) of the polymer solutions deposited on the strip (1 ). However in the description, for the sake of simplification, the same numbering will be kept to designate either the layers (10, 11) of the polymer solutions deposited on the strip (1), or the layers (10, 11) of the skin, 35 that is to say of the assembly (14) obtained after coagulation in the bath (4).

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/ It should be noted that the assembly (14) advantageously passes through washing tanks, not shown, arranged after the tank (5), before being wound on a take-up roller. In addition, the polymer solution (9) advantageously comprises a porophore agent in suspension and in this case it is necessary to provide, at the outlet of the tank (5), leaching tanks for this porophore which can, for example, be sodium chloride. This porophore may preferably be constituted by calcium carbonate of well defined particle size and in this case the assembly (14) is advantageously passed through tanks containing dilute acetic acid (of concentration generally between 10 and 0.1 and 15 % by weight), which increases the porosity and promotes communication between the pores of this layer (11) when the suspension of calcium carbonate reacts with acetic acid. Advantageously, the particle size of the calcium carbonate used is between 4 and 20 microns and it is put in the polymer solution (9) in an amount such that it corresponds from 2 15 to 20 times the weight of the polymer of the solution (9) . Optionally the assembly (14) can be wound directly on the cylinder (15) at the same time as a plastic grid thus disposed between the turns of the wound assembly (14) and it is possible to leach by soaking the wound assembly in acetic solutions, then wash with water. The skin obtained according to the process described above 20 comprises two flexible and distinct layers linked together over their entire surface.

The thickness of the layers (10 and 11) deposited on the strip (1) is chosen such that the artificial skin obtained has a first layer (11), applied on contact with the skin, the thickness of which is included between 25,100 and 2,500 microns, preferably between 200 and 1,500 microns, and a second layer (10), constituting an external protection, the thickness of which is between 10 and 200 microns, preferably between 20 and 100 microns.

Generally, the polymer solutions (8 and 9) are deposited on the strip (1) at a temperature between 1 and 50 ° C and preferably between 30 5 and 40 ° C. The temperature of the bath (4) is generally between 1 and 50 ° C and preferably between 5 and 40 ° C. Devices not shown in the figure possibly make it possible to continuously renew the bath while 'stirring it to homogenize it. Similarly, when the strip (1) comes out of the bath, the rubber scrapers (not shown) advantageously rub on these two faces to retain the liquid from the bath (4) as much as possible and cause it to drop 50 l into the container (5 ). Towards the driving cylinder (2), the strip (1) is advantageously dried by any suitable device (not shown).

The polymer solutions (8 and 9) are chosen so that the artificial skin obtained comprises a first layer (11), applied to the contact of the wound, the structure of which is cellular and porous, the diameter of the pores is generally between 10 and 100 microns, the porosity being between 70 and 95%. The porosity is defined as being the ratio (multiplied by 100) between the volume of the pores and the volume of the pores + the volume of the polymer of this first layer (11) of the artificial skin.

Preferably, the polymeric solution (9) is chosen in such a way that it makes it possible to obtain an artificial skin, the layer (11) of which is bioresorbable during the healing of the wound. The polymeric solution (8) is advantageously chosen so that the artificial skin obtained has a second layer (10), which offers selective permeability favoring: 15 - the evacuation of serum with retention of proteins from the wound, k - the protection of the wound against external microorganisms, such as microbes, viruses, yeasts or fungi, - maintaining at the level of the wound sufficient humidity to allow renewal of the tissues.

A section of this layer (10) has a dense appearance under a microscope (magnification 200).

The polymer in solution (9) is advantageously chosen from polymers based on polyamino acids. Thus, these polymers are generally polymers or copolymers of alpha-amino acids and alpha-amino acids comprising another carboxylic group, optionally esterified.

The preparation of such macromolecular substances is well known, in particular by "Synthetic Polypeptides" by Bamford, Elliot and Hauby, Academie Press, New-York (1956) and by Advances in Protein Chemistry 13, 243 30 et seq. (1958).

As esters of amino acids, it is possible in particular to use alkyl esters, for example lower alkyl (methyl, ethyl). The alpha-amino acids are, for example, glutamic acid and aspartic acid.

The polymer in solution (9) is preferably a copolymer of L-Leucine and an aspartic ester. The molar percentage of L-Leucine is! 1 6 * \ generally between 30 and 70%, the remainder of the copolymer comprising the esterified diacid. Such copolymers advantageously have a reduced specific viscosity measured at 25 ° C. in dichloroacetic acid at 2 g / liter of between 20 and 100 ml / g and preferably between 30 and 70 ml / g.

5 For the preparation of this copolymer, the N-carboxy-anhydrides (NCA) of leucine and of the ester of the alpha-amino diacid, (the COOH function in alpha not being esterified), are prepared first, by the action of the phosgene on the free amino acid functions of these substances. Next, the NCA is copolymerized in the presence of a polymerization catalyst, for example, sodium hydride and / or triethylamine. In the case where one starts with benzyl aspartate, one then proceeds advantageously to a transesterification of the copolymer obtained to replace the benzyl group with a methyl group. It is also possible to hydrolyze all or part of the ester functions of the copolymer so that it contains units of aspartic acid in its macromolecular chain. Advantageously, the copolymer contains in molar amount less than 15% of aspartic acid units and less than 5% of benzyl ester which has not been transesterified.

The solvents used to prepare the polymer solution (9) f are advantageously organic solvents, or mixed solvents, chosen in particular from dimethylformamide (IMF), N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), and tetrahydrofuran (THF). The concentration of the polymer solution (9) is advantageously between 1 and 20% by weight, and preferably between 2 and 15%, of poryuare.

The polymer of solution (8) is not bioresorbable and it is chosen, for example, from homopolymers of acrylonitrile or from polymers or mixtures of polymers comprising in their macromolecular chain recurring units originating from the polymerization of 1 ' acrylonitrile and of monomers comprising sulfonic groups and / or of the polymerization of acrylonitrile and of monomers comprising tertiary nitrogen which are quaternized.

Among the polymers based on acrylonitrile and of sulfonated monomer, which may be mentioned by way of illustration, those obtained by copolymerization of * acrylonitrile with (optionally salified) acids, vinyl sulfonic, 1-propene-1-sulfonic, allylsulfonic, methallylsulfonic , allyloxyethylsul-35 fonique; butene-2 and butene ~ 3 sulfonic; hexene sulphonic, in particular mk · »tr." "t -> * - * l'JtaWiOÎliT J — 1-11 ^ 1 iViw" '-> JkilMIÎW "ifc" * 1 XJ, tt> âw * w -i · ^ ".. ^. -. ·" JA "r - · --- * 4 ... ·>

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i 7 - - hexene-1 ~ sulfonic; methylbutenesulfonic, raethallyloxyethylsulfonic, allyloxy-3-propanol-2-sulfonic-1, allylthioethylsulfonic, allylthio-3-propanol-2-sulfonic-1; vinylbenzenesulfonic, in particular vinyl-3-benzene-sulfonic-1; vinyloxybenzenesulfonic, in particular vinyloxy-2 and vinyloxy-4-5 benzenesulfonic-1; isopropenylbenzenesulfonic, in particular isopropenyl-2 and isopropenyl-4-sulfonic-1; bromovinylbenzenesulfonic acid, in particular bromo-2 and bromo-4-vinyl-3-benzenesulfonic-1; alpha-methylstyrenesulfonic, alpha-ethylstyrene-sulfonic, isopropenylcumenesulfonic; mono, di- and trihydroxyvinylbenzene-sulfonic; 2,5-dichloro-vinylbenzenesulfonic-1, 10 isopropenylnaphthalene-sulfonic jVinyldichloronaphthalenesulfonic; o- and p-allylbenzenesulfonic; o- and p-methallylbenzenesulfonic; (o- and p-iso-propenylphenyl) -4-n-butane-sulfonic-1; vinylchlorophényJéthanesulfonique; o- and p-allyloxybenzene-sulfonic; o- and p-methallyloxybenzenesulfonic; vinylhydroxyphenylmethane-sulfonic; vinyltrihydroxyphenylethane sulfoni-15 ques; isopropyl-2-ethylene-sulfonic-1.

In these polymers, the proportion of units originating from acrylonitrile is generally between 40 and 99% and preferably between 60 and 96% (by weight relative to the total weight of the copolymer). As particular examples of such copolymers, mention may in particular be made of the copolymers of acrylonitrile with methallylsulfonic acid or its salts and the method of obtaining of which is described in French patent No. 2,076,854.

Mention may be made, among polymers based on acrylonitrile and of tertiary nitrogen monomer, by those obtained by copolymerization of acrylonitrile with vinyldimethylamine, allyldimethylamine, dimethylamino-1-propene-1, dimethylamino-2-propene-1, dimethylamina-1 butene-2, dimethylamino-4 butene-1, dimethylamino-3-butene-1, dimé-thylamino-3 méthÿl *> 2 propene-1, methylethylallylamine, vinyldiethylamine, dimethylamino-5 pentene-1, dimethylamino-4 methyl-3-butene-1y methyl-propylallylamine, allyldiethylamine, dimethylamino-6-hexene-1, ethyl-30 vinylbutylamine, allyldiisopropylamine , dimethylamino-3-propyl-2 pentene-1, • allyldibutylamine, dialkoylaminostyrenes, in particular dimethylamino styrene and diethylamino styrene, vinylpyridines in particular N-vinylpyridine, vinyl-2 pyridine, vinyl-3 pyridine , vinyl-4 pyridine, or their substitution derivatives such as methyl-5 vinyl-2 pyridine, et hyl'-5 35 vinyl-2 pyridine, methyl-6 vinyl-2 pyridine, dimethyl-4,6 vinyl-2 pyridine,

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8 ï * "N-vinylcarbazole, vinyl-4-pyrimidine, 2-vinylbenzimidazole. -

In these polymers, the proportion of units originating from acrylonitrile is generally between 40 and 99%, and preferably between 60 and 96% (by weight relative to the total weight of the copolymer).

The quaternizing agents of tertiary amine groups as well as the treatment conditions have been described in the literature. In general, esters of mineral acids such as alkyl halides, cycloalkyl or aralkoyl are used. Preferably, the alkyl, cycloalkyl and aralkyl radicals contain at most 14 carbon atoms.

As an example of such quaternizing agents, mention may be made of methyl, ethyl, propyl, cyclohexyl or benzyl chlorides, bromides and iodides, dimethyl or diethyl sulfates.

The copolymers with sulfonic groups or with quaternary ammonium groups described above are insoluble in water (solubility generally less than 1% by weight) at room temperature, while they are soluble in organic solvents, or solvent mixtures. Thus, the solvents used to prepare the polymer solution (8) are organic solvents or mixtures of solvents, preferably polar aprotics, chosen in particular from DMF, NMP, DMAC.

The concentration of the polymer solution (8) is generally between 1 and 50% of copolymer, and preferably between 5 and 40%.

The polymer solution (8) may further comprise a mixture of a polymer comprising in its macromolecular chain of units resulting from the copolymerization of acrylonitrile and of a monomer containing a sulfonic group and of a polymer comprising in its macromolecular chain units resulting from the copolymerization of acrylonitrile and of a quaternized quaternary nitrogen monomer, such as those described above. Such biionic polymers are included in the French patent published under Mo. 2,144,922.

The artificial skin according to the present invention is advantageously cut to formats practical for its clinical use and is generally stored in the wet state after being treated with a hydrophilic adjuvant such as for example glycerin, or preferably polyethylene glycol of molecular weight of, for example, between 300 and 1000. This impregnation treatment with a hydrophilic adjuvant can take place in tanks, just before the skin (14) is wrapped around the receiving roller (15).

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An artificial skin is continuously prepared using the apparatus, according to the figures, previously described.

The polymer solution (8) introduced into the couleuse (6) is a 19.6% solution in DMF of acrylonitrile-sodium methallylsulfonate copolymer, comprising 0.6 Eq / kg of SO 4 group and whose reduced specific viscosity at 5 g / l in DMF (containing 4.25 g / l of sodium nitrate) at 25 ° C is 200 ml / g. This copolymer comprises by weight 90.5% of units originating from acrylonitrile.

The polymer solution (9) introduced into the pouring machine (7) comprises: - 8 g of a leucine-methyl aspartate polycondensate (molar ratio 62/38, whose reduced specific viscosity measured at 25 ° C. in diehloroacetic acid at 2 g / 1 is: 50 ml / g), 15 - 108 g of N-methylpyrrolidone, - 132 g of tetrahydrofuran, - 80 g of calcium carbonate (particle size 12 microns).

The casting machine (6) makes it possible to deposit on the strip (1), made of stainless steel 0.5 mm thick, a layer (10) thick 100 microns, while the casting machine (7) makes it possible to deposit, on the layer (10), a layer (11) 400 microns thick. The positioning of the casting machine (7) is such that the two layers (10 and 11) are in contact 12 seconds before being immersed in the coagulation bath (4).

The width of the strip is 20 cm and the width of the layers (10 25 and 11) is 16 cm, which corresponds to the length of the slitter slot (6 and 7).

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The coagulation bath (4) is a 1% (volume / volume) solution of acetic acid and 0.2% (volume / volume) of "DECON 90" maintained at 20 ° C. The "DEC0N 90" marketed by the company PR0LAB0 (No. 23 280 on catalog 30 year 1975) is an aqueous solution of Κ0Η, triethanolamine, sodium citrate, sodium laurylethoxysulfate, polyoxyethylene alkylphenol and alkylbenzenesulfonic acid.

The polymer solutions (8 and 9) are at 20 ° C in the flowers (6 and 7).

35 The length of strip (1) immersed in the bath (4) being 1 meter, * ^ · 1Μ> ΙΙ (· .ι <* Μ "" · "· ** ** '> >·>>' ^." - - * · -U- mi * \ Μ +> Λι ** ηΐ * η ~ »· ~ · ^ ·" * - * Ψ · * τ · '<· ΑΜί. ··>' ΙΛ. '.. < > "*** s, ·." ............... ...........

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v 10 = the speed of advance of the strip is adjusted to 0.25 m / min so that the coagulation time is sufficient.

The assembly (14) is collected on the cylinder (15) at its exit from the coagulation bath, after it (14) has been released from the support strip at 5 (3a).

The assembly (14) is then unwound from the cylinder (15) and soaked for 3 hours in a solution identical to that of the coagulation bath (4) described above.

The assembly (14) is then rinsed with distilled water for two 10 hours. ; The assembly (14) is then cut into elements 20 cm long by 14 cm wide and impregnated with an 80/20 mixture (by volume) of polyethylene glycol of molecular weight 300 and of PBS / No solution. 83 501 from the BI0MERIEUX catalog.

PBS is an aqueous solution comprising the following elements: 15 - NaCl 8 g / 1 - KC1 0.2 g / 1 - CaCl2, 2H20 0.132 g / 1 - MgCl2, 6H20 0.100 g / 1 - Na ^ PO ^, 2H20 1.441 g / 1 20 - KH2ïO4 0.2 g / 1

The final product is advantageously presented in a waterproof heat-sealed sachet and sterilized by Y radiation (2.5 megarads).

The artificial skin thus obtained comprises an outer layer (10) of acrylonitrile copolymer, the thickness of which is 65 microns, and the appearance of which is dense under a microscope (magnification 200) and a bioresorbable layer (11) of which the thickness is 280 microns and the pore diameter varies from 20 to 60 microns.

The artificial skin thus produced has a water vapor permeability of 1.35 1 / jm (at 22 ° C, 60% EH) and a water flow rate under 2 bars of differential pressure of 1.150 1 / jm .

Samples of this sterilized artificial skin were applied, in 49 patients, to areas that were the subject of skin samples for autografts. It emerges from these clinical trials that the tolerance has been very good and in particular no allergic reaction has been observed. The artificial skin was left on each patient during the whole healing period of the place of graft removal. At the end of the healing period, it was found that the bioresorbable layer (11) had completely disappeared. The experimenters insist on the fact that the areas of graft removal stopped within a few hours, after the intervention, being painful, contrary to what usually happens. In the two series of patients studied, we observed, in most patients, a reduction of 3 to 4 days on average in the usual healing time. The cicatrization left a scar area of good „quality and very satisfactory appearance.

10 Although the artificial skin described above was obtained by directly pouring the polymer solution (8) on the support (1), that is to say on the metal strip in motion, it is understood that the it is not beyond the scope of the invention in the hovel where the polymer solution (3) is poured onto a ribbon of porous fabric or nonwoven, having the same speed of advance and substantially the same width as that of the band (1). This ribbon of very fine thickness (of the order of 20 to 60 microns) can be made of polypropylene, polyester or polyamide in particular. It is supported by the. strip (1) at the time of the deposition of the polymer solutions (8 and 9) and is an integral part of the artificial skin obtained after the latter has been released from the strip (1) at the point marked with (3a). Advantageously, this ribbon is only found in the second layer (10) of the skin obtained, of which it strengthens the mechanical strength.

On the other hand, the polymer solution (8) can optionally be poured onto a film resting on the strip (1) and advancing with it (at the same speed), said film being subsequently separated from the artificial skin (14 ) obtained.

An advantageous variant of the process consists in not wrapping the skin (14) around a receiving roller (15) and in carrying out continuously, in successive tanks, the operations of coagulation, soaking, rinsing, treatment of impregnation, then (outside the tanks) for cutting and conditioning said skin.

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Claims (9)

2. Artificial skin according to claim 1, characterized in that the polymeric solutions are chosen so that said skin comprises: 10. a first layer (11) applying aUj wound contact, absorbable by the body, of biodegradable, alveolar, hygroscopic material, with communicating cells, spongy and permeable to liquids, - a second layer (10) constituting an external protection, permeable to gases but maintaining sufficient humidity and stopping external pathogenic microorganisms. 3. Artificial skin according to claim 2, characterized in that: - the polymer solution (9) making it possible to obtain the first layer (11) essentially comprises a polymer or a copolymer of alpha-amino acids, - the polymer solution (8) making it possible to obtain the second layer (10) essentially comprises a polymer chosen from homopolymers of acrylonitrile or from polymers or mixtures of polymers comprising in their macromolecular chain recurring units originating from the polymerization of l acrylonitrile and of monomers comprising sulfonic groups and / or of the polymerization of acrylonitrile and of monomers comprising tertiary nitrogen which are quaternized. 4. Artificial skin according to claim 3, characterized in that the polymer solution (9) making it possible to obtain the first layer (11) comprises a polycondensate of leucine and aspartic acid, the carboxylic group of which is furthest from the amino group is, at least in part, esterified by a methyl group, and in that the polymer solution (8) making it possible to obtain the second layer (10) comprises a polymer obtained by - copolymerization of acrylonitrile and sodium methallylsulfonate. 5. Artificial skin according to any one of claims 2 to 13 4, characterized in that the polymer solution (8) making it possible to obtain the layer (10) comprises a polymer whose proportion of the units originating from acrylonitrile is greater at 40%, by weight, relative to the total weight of the polymer. 6. Artificial skin according to any one of claims 2 to 5, characterized in that the polymer solution (9) making it possible to obtain the first layer (11) comprises a porophore agent in an amount such that it corresponds from 2 to 20 times the weight of the polymer in this solution. 7- Artificial skin according to any one of the preceding claims, characterized in that the polymer solution (9) comprises compie; porophore agent of calcium carbonate and in that the coagulation bath (4) is an aqueous solution comprising between 0.1 and 15% acetic acid (by weight). 8. Artificial skin according to any one of the preceding claims, characterized in that the polymer solutions (8 and 9) are poured onto a moving endless strip (1). 9- Artificial skin according to any one of claims 2 to 8, characterized in that the polymer solution (8) comprises from 1 to 50% by weight of polymer, in that the polymer solution (9) comprises between 1 and 20 20% by weight of polymer, in that the solution (8) intended to constitute the outer layer (10) of the skin is poured onto the support (1) and in that the solution (9) is poured onto the layer (10 ) having just been deposited on the support (1). 10. Artificial skin according to any one of the preceding claims, characterized in that the polymer solutions (8 and 9) are poured onto a reinforcing tape disposed on the support (1), said tape being an integral part of the skin obtained after its release from the support (1).