Field of the Invention

[0001] The invention relates generally to adhesion materials and a method of their production. More particularly, the present invention relates to a new type of adhesive including the adhesion material that binds a pad, devices or other objects to the skin through hydrogen bonds.

Background of the Invention

[0002] An adhesive is a product that can be applied to almost every type of medical device to bind the medical device to a skin of a person. For example, the adhesive can be applied to a simple wound dressing to enable the wound dressing to bind more tightly to the skin or to a more complex product, such as but not limited to, an ostomy bag that needs to be held in place on the skin.

[0003] In the market of medical adhesives there are several solutions known that comprise a mixture of one or more adhesion materials, such as Acrylate, hydrocolloid or silicone. In recent years, there have been extensive advances in the adhesives industry which have produced new advances in the adhesion materials in a widening spectrum. For example, it is possible to produce variations of the adhesion material by adding different materials to the final composition and thereby enable properties of the adhesion materials to be tailored to meet specific application requirements, including biostability, sterilization effects, and mechanical properties.

The main types of adhesion materials used currently in the medical device area are cyanoacrylate, fibrin glue, GRF (Gelatin, resorcinol, formaldehyde), hydrogel and hydrocolloid and other adhesion materials with small market share or in research as the silicones, poly ethylene glycol, albumin, chitosan, gelatin. These adhesion materials compositions have known disadvantages, such as stripping (removing the adhesion material from the surface), mechanical injury due to tension, allergic contact resulting in dermatitis, folliculitis and skin maceration. [0004] Beside the afore-mentioned disadvantages, a hydrocoUoid dressing also presents the further disadvantages that the hydrocoUoid dressing may dislodge from contact with the skin due to shearing or friction. The hydrocoUoid dressing is also not recommended for use with infected wounds due to fluid discharge as the hydrocoUoid dressing will also dislodge from the wound with heavy drainage. Finally, the odor when the hydrocoUoid dressing is removed can be very strong and the removal may injure fragile skin.

Prior Art

[0005] As was explained before, in this market it is possible to find several types of adhesion materials that use different strategies to stick to the skin, such as chemically, electrostatically or mechanically. The chemical adhesion materials comprise a large quantity of materials, such as but not limited to acrylic, styrene-isoprene-styrene block copolymers, high molecular weight polyisobutylenes loaded with glycols, fat, oil, glycerol esters or surfactants.

[0006] Silicone adhesives are also widely employed as skin friendly adhesives. In the patent document, EP 2853573 Al, for example, a diol was reacted with dicarboxylic acid through the polycondensation method, to develop an adhesion material which is friendly towards the skin.

[0007] According to the US patent number US 5308887 A and international patent application No WO 2017/021448 Al there are some pressure sensitive adhesives that are applied in strips, swirls, or waves. This type of adhesive refers to any releasable adhesive or releasable tenacious means. Suitable adhesion materials include, water- based pressure-sensitive adhesion materials, such as acrylate adhesives, natural rubbers, synthetic rubbers, vinyl acetates, silicones and poiyurethanes. These adhesion materials can be based on emulsion or solvent-borne adhesives of natural or synthetic polyisoprene, styrene-butadiene, or polyacrylate, vinyl acetate copolymer.

[0008] Another type of adhesion material called hot melt adhesives are also known. According to the patent number EP 2756830 Bl, a pressure-sensitive hot melt adhesive comprises substantially saturated block copolymer, tackifying resin, and polybutene. This hot melt composition exhibits adhesive stability when exposed to ultra-violet light and is stable when contacted with piasticized surfaces. These block copolymers include linear or radial co-polymer structures having the formula (A-B) wherein block A is a polyvinylarene block and block B is a poly(monoalkenyl) block. Block A, includes polystyrene, polyalpha-methylstyrene and polyvinyltoluene. Block B, can include, conjugated diene elastomers such polybutadiene or polyisoprene or hydrogenated elastomers such as ethylene butylene or ethylene propylene or polyisobutylene.

[0009] Commercial examples of these types of block copolymers include Kraton™ elastomers from Shell Chemical Company, Vector ™ elastomers from Dexco, Solprene™ from Enichem Elastomers and Stereon™ from Firestone Tire & Rubber Co.; hot melt adhesive based on olefin polymers and copolymers where in the olefin polymer is a terpolymer of ethylene and co-monomers, such as vinyl acetate, acrylic acid, methacrylic acid, ethyl acrylate, methyl acrylate, n-butyl acrylate vinyl silane or maleic anhydride. Commercial examples of these types of polymers include Ateva (polymers from AT plastics), Nucrel (polymers from DuPont), Escor (from Exxon Chemical).

[0010] Another type of adhesion material existing in the market is called a gecko solution. This gecko solution is a combination of microfibers and nanofibers that connect to the skin using a mechanical and electrostatic connection that results from the cumulative effect of van der Waals forces between the millions of setae on the feet pads in intimate contact with the surface the gecko is climbing on. The patent application US No 2014/0272272A1 uses an electrostatic dry adhesive device having a micro- structured element formed directly into a contact surface of an electrostatic adhesive. The micro-structure in the form of microwedges can be molded into surface of an electrostatic adhesive. This document refers the use of at least one electrode that comprises a conductive mesh or fabric.

[0011] US Patent Application Publication No 20120288680 Al uses a micro-featured and nano-featured surface, and a compliant surface having a hardness of about 60 Shore A or less. This type of adhesion composition needs flat surfaces for adhesion, such as polymer, metal or other. [0012] The study "Adhesion and friction of an isolated gecko setal array: The effects of substrates and relative humidity", by Y. Tian, showed that water affects the adhesion of the setal array by changing the Hamaker constant, and when the gecko encounters a surface with a higher surface energy or a more humid ambient environment, the gecko enjoys climbing more flexibly. Unfortunately, and according to the study "Surface free energy of the human skin and its critical surface tension of wetting in the skin/surfactant aqueous solution/air system", by Krawczyk J, the skin surface is a low-energetic one. The critical surface tension of the skin wetting depends on the type of surfactant. In this respect, non-ionic surfactants seem to be the most appropriate.

[0013] Maleic anhydride has also been studied as an adhesion material. The researcher Hernandez Sierra JF studied the application of this type of materials in "Bactericidal capacity of silver nanoparticles associated with Gantrez S-97 on Streptococcus mutans". He concluded that the addition of Gantrez 2% to silver nanoparticles does not alter its antimicrobial effect. [Hernandez, Sierra JF, Salas, Lopez EK, et al. "Bactericidal capacity of silver nanoparticles associated with Gantrez S-97 on Streptococcus mutans."; 2010 Winter;35(2): 183-5.] Anastasia Ripolin studied the application of this type of material in microneedle patches to be used in humans. She concluded that the use of such larger patches by patients can be successful, potentially opening up the possibility for a significant expansion of the size of the market for transdermal drug delivery. [Ripolin, Anastasia; James, Quinn; et al. "Successful application of large microneedle patches by human volunteers ". International Journal of Pharmaceutics, Vol.521, Issues 1-2, 15 April 2017, 92-101.] E. Blanco Garcia has studied microspheres (Ms) based on zein (ZN) and Gantrez® AN 119 (PVMMA) that were prepared by spray-drying and coated with a pH-sensitive polymer (Eudragit® FS30D) in intestinal inflammatory disorders. The authors concluded that ZN/PVMMA microspheres is a serious alternative for delivering the medicine to reduce the inflammatory activity at intestinal regions affected by inflammatory bowel diseases. [Garcia, E. Blanco; Espinar, F.J. Otero; "Development and characterization of antiinflammatory activity of curcumin- loaded biodegradable microspheres with potential use in intestinal inflammatory disorders". International Journal of Pharmaceutics, Volume 518, Issues 1-2, 25 February 2017, 86-104]. This affinity has been studied and similar solutions patented by other authors, one of the studies showed the capability of the maleic anhydride to connect with the hydroxy or hydroxy 1 group.

[0014] The functionalization of polymers with this additive material is disclosed in the U.S. Patent No. 6,451,919 Bl (1998). The patent teaches how the polyolefms can be functionalized with maleic anhydride and at least one high-boiling ester of the latter, and a process for their preparation in high yields, with high degrees of functionalization, without the production of by-products of cross-linking or degradation is disclosed.

[0015] In US. 8,940,132 are disclosed the interface modifiers, e.g., surface active agents, that may be used in functionalized polymers, preferably maleic anhydride grafted polyolefms, to improve the adhesion with cellulosic pulp fibers.

[0016] US 8,940,278 focused in the efficacy enhancing agent that preferred copolymers of maleic anhydride or acid with another polymerizable ethylenically unsaturated monomer. The maleic anhydride was also used in the US 8,906,406 and 8,907,153 for a mucoadhesive medicinal containing at least one active substance, in which a matrix comprises a mixture that comprises sodium carboxymethyl cellulose, polyvinyl alcohol and hydroxypropylmethyl cellulose. The adhesion material comprises at least one type of cellulose, derivatives, and for example maleic acid anhydride. As matrix- forming polymers which can be components of a mucoadhesive formulation, the following polymers were taken into consideration as raw materials: Polyvinyl alcohol (e.g. Mowiol ^(R) ; cellulose derivatives, especially the types of Polyox 10, Polyox 80, Polyox 205, Polyox 301, Polyox 750 (made by the firm of Union Carbide); copolymers of methyl vinyl ether and maleic acid anhydride (Gantrez-Copolymers, especially the types of ES, MS, S; by the firm of ISP Global Technologies GmbH). According to the US. Pat. No. 8,940,132, it is preferably, the surface-active agent(s) presented in an amount greater than 2% by weight and less than 15% by weight of the entire composition of the composite, and more preferably in an amount less than or equal to 10% by weight.

[0017] Further patent applications are known which describes similar compositions. For example International Patent Application No. WO2017/075320 describes an antimicrobial adhesive made of silicone. [0018] International patent application No. WO2010043346 teaches an aqueous solution of materials, or materials solubilized in conventional cosmetically or dermopharmaceutically acceptable solvents selected from the group consisting of ethanol, propanol, isopropanol, propylene glycol, glycerin, butylene glycol, or polyethylene glycol and mixtures thereof.

[0019] US patent application No. US2013/0052236A1 teaches an adhesive based on mucoadhesive aspect comprises an alginate, phloroglucinol, maleic acid and an alkyl vinyl ether, as well as glycerol.

[0020] US patent application No. US2007/0009582A1 teaches a plasticizer. This is only used to reduce the melting temperature. The adhesive is made only from hydrophobic block(s) consists essentially of polymerized (meth)acrylic ester. The glycerol here is used as said aqueous solution and not to be used to create hydrogen bonds.

Summary of the Invention

[0021] The adhesion material presented in this document is used in a novel type of adhesion material to secure a medical device to a skin of a human or an animal. This adhesion material was developed to overcome the main disadvantages of the current types of adhesion materials, namely the mechanical injury due to tension, allergic contact dermatitis, folliculitis and maceration. To overcome the disadvantages of the current adhesion materials, the adhesion material developed has the capability to bind to the water molecules that exist on top of the skin of the human or animal and not directly to the skin itself. To achieve this, the adhesion material uses hydrogen bonds. The binding with the hydrogen bonds reduces the number of skin cells that are removed on removal of the material as known in the prior art adhesion material, since the adhesion material taught in this document is not in direct contact with the skin.

[0022] As was explained above, the adhesion material developed is based on the principal of hydrogen bonds. The hydrogen bonds are an attractive force between the hydrogen atom attached to an electronegative atom of one molecule and an electronegative atom of a different molecule. Usually the electronegative atom is oxygen, nitrogen, or fluorine, which has a partial negative charge. The hydrogen has the partial positive charge. This bond is not nearly as strong as normal covalent bonds within a molecule (about 1/10 as strong). However, this strength is enough to have important ramifications on the properties of water.

[0023] To achieve a good adhesion between the adhesion material of this document and the skin, the atoms of O- Ή need to be at distance of around 2.06 A apart. At this distance, there exists both an electrostatic and covalent component of the bonding. If the distance between the two atoms increases or the amount of water is reduced, the adhesion strength of the adhesion material will be reduced to substantially zero, which will help to remove the medical device that is held to the skin by the adhesion material of this document. With this, the problems known in the art such as stripping, mechanical injury due to tension, allergic contact dermatitis, folliculitis, maceration are eliminated or at least substantially reduced.

[0024] In one aspect, the adhesion material is a composition that comprise a mixture or the reaction of polyethylene glycol (PEG), preferably from 200 to 8000 g/mol, with a sugar, such as sucrose, maltose, lactose or fructose, and/or a sugar alcohol (also called polyhedric alcohol) such as xylitol (152 g/mol) or sorbitol, glycerol (98 g/mol), castor oil (150 g/mol), ascorbic acid (176 g/mol), citric acid (190 g/mol), lignin (1513 g/mol), oleic acid (284,47 g/mol) and lauric acid (200 g/mol). It is known that PEG is a linear molecule in which the OH groups are localized at the end of the molecular chain. This localization will allow controlling the flexibility of the final material. The other materials due to their quantity of the hydroxy groups -OH will allow an increase the hydrogen bonds in the adhesion material and thus between the adhesion material and the water in the skin. The lauric acid or oleic acid will provide water repellence.

[0025] To the previous composition is added one of the following compounds in manner to promote the necessary adhesion: Polypropylene grafted with maleic anhydride or Polyethylene grafted with maleic anhydride or poly (ethylene-alt-maleic anhydride) or polystyrene-block-poly(ethylene-ran-butylene)-block-polystyr ene-graft- maleic anhydride or polyisoprene-graft-maleic anhydride or poly(methyl vinyl ether-alt- maleic anhydride) or poly(isobutylene-alt-maleic anhydride) or poly(maleic anhydride- alt- 1-octadecene) solution. [0026] The materials presented above have on their structure a molecule that has affinity with water. This affinity is given mainly due to maleic anhydride molecule. This molecule is reported by Arieny Rodrigues, in the study "Effect of compatibilization and reprocessing on the isothermal crystallization kinetics of polypropylene/wood flour composites", in Polimeros, vol.23, no.3, Sao Carlos, 2013. The presence of a compatibilizer between two materials, such as a polymer and wood, decreases the interfacial tension, increasing the adhesion between the two materials and provides wettability, thus preventing agglomeration. In the market, there exist several materials grafted with maleic anhydride. It is possible to find materials with a concentration of this additive of between 1 to 10 % in weight.

[0027] There are a large number of materials that are grafted with these additive and suitable ones of the materials can be selected by defining requirements according with the end application. To be more specific the material will be selected based on the level of erythema (redness of skin) caused by the material, the capability to create the adhesion on the skin at the temperature of the body (i.e. between 37°C and 40°C) and the capability to support a weight of 1 kg during 3 days without losing adhesiveness.

[0028] Another factor that will be considered to select the material is the manufacturing technique. According to European Chemicals Agency (ECHA, https://echa.europa.eu/substance-information/-/substanceinfo /100.003.247), maleic anhydride may cause irritation to the respiratory tract, eyes, exposed and skin. Maleic anhydride is also a skin and respiratory sensitizer.

[0029] Lignin is another material that can be used in the adhesion material, since lignin is an amorphous natural polymeric material that is based on a phenylpropane derivate, with large number of hydroxyl groups on their molecule chain, one of the most abundant materials and renewable resources on earth. The lignin-based adhesives have potentials for engineering applications due to their environmental suitability and economic and technical feasibility.

[0030] The manufacturing techniques that can be used to add the adhesion material to the medical device are the nano-spray, nano-printing and polymer brush. The polymer brush is a technique that described by William J. Brittain in the work "A Structural Definition of Polymer Brushes", Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 45, 3505-3512 (2007). A polymer brush is an array of macromolecular chains which is attached or tethered to a surface and in sufficient proximity so that the unperturbed solution dimensions (in a good solvent) of the chains are altered. In the study, Brittain inferred that, to obtain a good alignment, it is necessary that the polymers have a low molecular weight of 14,500 g/mol.

[0031] A non- limiting example of the adhesive patch with the adhesion material will now be described. The adhesive patch has the following layers:

a) an external layer made of a water proof and breathable material (as for example ePTFe, silicone, thermoplastic polyurethane (TPU), polyether block amide (PEBA) or ethylene-vmyl acetate (EVA), with a thickness between 50 um -500 μηι);

b) an intermediate layer made of non- woven or woven fabric (non- limiting examples include polyamide, polyester, cotton, or fibers of polypropylene or polyethylene);

c) an inner layer of the adhesion material.

[0032] The inner layer is made of the adhesion material taught above and can interact with the water that exists in the skin. This adhesion material is composed by a mixture or a reaction result of polyethylene glycol and citric acid and ascorbic acid and glycerol as well as lauric acid and/or oleic acid with polypropylene grafted with maleic anhydride or Polyethylene grafted with maleic anhydride or) or poly (ethylene-alt- maleic anhydride) or polystyrene-block-poly(ethylene-ran-butylene)-block-polystyr ene- graft-maleic anhydride or polyisoprene-graft-maleic anhydride or poly(methyl vinyl ether-alt-maleic anhydride) or poly(isobutylene-alt-maleic anhydride) or poly(maleic anhydride-alt- 1-octadecene) or poly(ethylene glycol)methyl ether methacrylate solution polyethylene glycol, with a polyol.

[0033] The process used to react different polyols is esterification. The materials polyethylene glycol, citric acid, ascorbic acid, glycerol, Xylitol as well as lauric acid and/or oleic acid are added together or separated, mixed at temperatures between 80°C to 200°C, for lh to 24h, using pressures of between a near vacuum (zero atmosphere) and 2 atmospheres. As an example, the structure of the polyol could be like the one presented in figure 12. [0034] In one aspect, the adhesion material comprises a mixture of polyethylene glycol and citric acid and ascorbic acid and glycerol and xylitol and lauric acid and/or oleic acid.

[0035] In another aspect, the adhesion material comprises a mixture of polyethylene glycol and citric acid and ascorbic acid and glycerol and xylitol and lauric acid/ oleic acid with polypropylene grafted with maleic anhydride.

[0036] In another aspect the adhesion material comprises, a mixture of polyethylene glycol and citric acid and ascorbic acid and glycerol and xylitol and lauric acid/oleic acid and the material resulted by their reaction of the different polyols with Polyethylene grafted with maleic anhydride.

[0037] In an aspect the adhesion material comprises a mixture of polyethylene glycol and citric acid and ascorbic acid and glycerol and xylitol and lauric acid/oleic acid with poly (ethylene-alt-maleic anhydride).

[0038] In an aspect, the adhesion material comprises, a mixture of polyethylene glycol and citric acid and ascorbic acid and glycerol and xylitol and lauric acid/oleic acid with polystyrene-block-poly(ethylene-ran-butylene)-block-polystyr ene-graft-maleic anhydride or polyisoprene-graft-maleic anhydride or poly (methyl vinyl ether-alt-maleic anhydride).

[0039] In an aspect, the adhesion material comprises a mixture of polyethylene glycol and citric acid and ascorbic acid and glycerol and xylitol and lauric acid/oleic acid with poly(isobutylene-alt-maleic anhydride) .

[0040] In an aspect, the adhesion material comprises a mixture of polyethylene glycol and citric acid and ascorbic acid and glycerol and xylitol and lauric acid/oleic acid with poly (maleic anhydride-alt- 1-octadecene).

[0041] In an aspect, the adhesion material comprises a mixture of polyethylene glycol and citric acid and ascorbic acid and glycerol and xylitol and lauric acid/oleic acid with poly(ethylene glycol)methyl ether methacrylate solution. [0042] In an aspect, the adhesion material comprises a mixture of 14% to 16% in weight of polyethylene glycol and 18% to 21% in weight of citric acid and 2% to 4% in weight of ascorbic acid and 4% to 6%> in weight of glycerol and 5% to 7% in weight of xylitol and 1% to 2% in weight of oleic acid.

[0043] In one aspect, the adhesion material comprises a mixture of 14% to 16% in weight of polyethylene glycol and 18% to 21% in weight of citric acid and 2% to 4% in weight of ascorbic acid and 4% to 6% in weight of glycerol and 5% to 7% xylitol and 1% to 2% in weight of lauric acid.

[0044] In a further aspect, xylitol can be replaced by another sugar alcohol such as sorbitol, as well as by a sugar such as fructose, lactose, maltose or sucrose.

[0045] In one aspect, the polyol resulted from the reaction of the different polyols can also be used, in this case is used between 48% and 52% in weight. The adhesion material has 48 % to 52% in weight of butyl ester of methyl vinyl ether grafted with maleic anhydride or Polypropylene grafted with maleic anhydride or Polyethylene grafted with maleic anhydride or poly (ethylene- alt-maleic anhydride) or polystyrene- block-poly(ethylene-ran-butylene)-block-polystyrene-graft-ma leic anhydride or polyisoprene-graft-maleic anhydride or poly(methyl vinyl ether-alt-maleic anhydride) or poly(isobutylene-alt-maleic anhydride) or poly(maleic anhydride-alt- 1-octadecene) or poly(ethylene glycol)methyl ether methacrylate solution.

Brief description of the drawings

[0046] For easier understanding, the figures and tables representing preferential embodiments not intend to limit the object of the present description.

[0047] Fig. 1 shows the molecular structure of polypropylene grafted with maleic anhydride;

[0048] Fig. 2 shows the molecular structure of polyethylene grafted with maleic anhydride. [0049] Fig. 3 shows the molecular structure of poly (ethylene-alt-maleic anhydride).

[0050] Fig. 4 shows the molecular structure of polystyrene-block-poly(ethylene-ran- butylene)-block-polystyrene-graft-maleic anhydride.

[0051] Fig. 5 shows the molecular structure of polyisoprene-graft-maleic anhydride.

[0052] Fig. 6 shows the molecular structure of poly(methyl vinyl ether-alt-maleic anhydride).

[0053] Fig. 7 shows the molecular structure of poly(isobutylene-alt-maleic anhydride). [0054] Fig. 8 shows the molecular structure of poly(maleic anhydride-alt- 1-octadecene). [0055] In Fig. 9 is an example of how the materials can be placed.

[0056] Fig. 10 shows the molecular structure resulted by the reaction between the different polyols.

[0057] Fig. 11 show the results of adhesion strength of the adhesive comparing with products already in the market.

[0058] Fig. 12 show the material attached to the skin Detailed description of the Invention Example 1

[0059] In this example the application of the composition will be illustrated. The composition used in the adhesion material on the adhesive patch as shown in the figure 12, is a mixture of

• 14% to 16% by weight of polyethylene glycol 400;

• 18%) to 21 % by weight of citric acid;

• 2%> to 4%) by weight of ascorbic acid;

• 4%) to 6%) in weight of glycerol;

• 5 % to 7% In weight of xylito 1

• 1%) to 2%> in weight of oleic acid. [0060] The biopolymer resulted from the reaction of the different polyols is mixed, in this case is used between 44% and 56% in weight with the maleic anhydride polymer. The adhesion material comprises 44% to 56% in weight of poly(methyl vinyl ether-alt- maleic anhydride). The materials to be use in the adhesion material are mixed by hand or with the help of a mixing machine at temperatures between 23°C and 90°C, and with a velocity of mixing between 1 rpm and 1000 rpm. Poly(methyl vinyl ether-alt-maleic anhydride) was selected because this material presents the molecular length necessary to interact with the deep zone of the skin.

[0061] A non- woven or a woven fabric, such as but not limited to polyamide, polyester, cotton, fibers of polypropylene or polyethylene, is used as the substrate for the adhesive patch. This substrate is a layer of a material with the capability to protect the adhesion material and the skin from atmosphere.

[0062] The adhesive patch was obtained as follows. Firstly, a protective layer with a thickness between 50 μιη and 500 μιη of silicone was applied at room temperature to one of the faces of the non-woven or woven fabric. This silicone layer is applied at room temperature using the technique of knife-coating and/or spraying and/or printing. The protective layer was cured up to a maximum of three hours at temperatures between 23°C to 100°C.

[0063] After this cure period the adhesion material was added to the other one of the faces of the non-woven or woven fabric by knife-coating, nano-printing or nano-spray.

Example 2

[0064] This example illustrates a way of producing an adhesion material to be used in a hot and cold therapy adhesive patch. An adhesion material of a butyl ester of methyl vinyl ether grafted with maleic anhydride was selected because this composition presents the molecular length necessary to interact with the deep zone of the skin and has in its structure the maleic anhydride necessary to adhere to the skin.

[0065] The adhesion material can be made through the following process:

The composition to be used in the adhesion material is a mixture of: • 14% to 16%) by weight of polyethylene glycol 400;

• 18%) to 21 % by weight of citric acid;

• 2%> to 4%o by weight of ascorbic acid;

• 4%o to 6%) in weight of glycerol;

• 5 % to 7% In weight of xylito 1

1% to 2% in weight of oleic acid. The polyol resulted from the reaction of the different polyols can also be used, in this case is used between 44% and 56%> in weight. The adhesion material must have 44 % to 56% in weight of a butyl ester of methyl vinyl ether grafted with maleic anhydride.

[0066] The materials were mixed for between 1 min to 24 hours at a temperature between 23°C and 110°C, more preferably between 30-90°C. The materials were mixed between 1 min to 24 hours.

[0067] The adhesion material is added to the face of the adhesive patch that will be in contact with the skin through knife-coating, nano-printing or nano-spray.

[0068] A protective layer of polyether block amide (PEBA) with a thickness of between 50 μιη and 500 μιη is added to the external face of the medical device. The protective layer will be used to protect the adhesion material from the atmosphere. The protective layer will be added to the adhesive patch by painting or thermo forming.

Example 3

[0069] This example is a way of applying the adhesive to a wound dressing that uses a non-woven or woven fabric. A protective material is also used to protect the adhesion material from the atmosphere, and the adhesion material will enable adhesion to the skin. Poly (ethylene-alt-maleic anhydride) was used as the adhesion material because this adhesion material has the capability to interact with the water in the skin, as described above.

[0070] This adhesion material was made through the following process:

The adhesion material to be used in the adhesive is a mixture of • 14% to 16% by weight of polyethylene glycol 400;

• 18%) to 21 % by weight of citric acid;

• 2%> to 4%) by weight of ascorbic acid;

• 4%) to 6%) in weight of glycerol;

• 5 % to 7% In weight of xylito 1

• 1 % to 2%> in weight of oleic acid..

[0071] The polyol resulted from the reaction of the different polyols can also be used, in this case is used between 44% and 56% in weight. The adhesion material must have 44% to 56% in weight of poly(ethylene glycol)methyl ether methacrylate solution.

[0072] To mix the different components of the adhesion material, temperatures between 23°C and 110°C, and more preferably between 30-90°C, were used. The materials were mixed between 1 min to 24 hours. These components were mixed by hand or with a help of a mixer with a mixing velocity between 1 rpm and 1000 rpm for between 1 min to 2 hours.

[0073] The adhesion material was applied to one face of the non-woven fabric made of a polyamide or a layer of thermoplastic polyurethane (TPU) with thickness of between 50 μιη and500 μιη.

Testing

[0074] Tests regarding the adhesion capability of the adhesives were made, and these are shown in Fig. 12. These tests were made according with the standard ASTM D 3359-97 "tape test". They compared the adhesion strength of the examples of this document invention with prior art materials, namely Combihesive IIS from Convatec and Askina "Thinsite" from BBraun. These tests evaluated the maximum and the minimum force needed to remove the adhesive. The figure shows that to remove the adhesive was necessary less force (10N) compared with the ones in the state-of-the-art (13N for Askina and 12 for Combihesive). Relatively to the minimum force the adhesive developed needed more force (2N) comparatively to the Convatec (IN) but need less force when compared to the product of BBraun (8N).