FR3109387A1 - Thermoplastic elastomeric antimicrobial film, composition and manufacturing process for obtaining it - Google Patents

Abstract

[Title: Thermoplastic elastomeric antimicrobial film, composition and manufacturing process for obtaining it The invention relates to a thermoplastic elastomeric antimicrobial film (1) made of polyvinyl chloride or polyurethane or a mixture of these two materials. According to the invention, the film is cast in its mass and has a thickness of between 50 μm to 300 μm, the film incorporates a biocide of between 0.1 to 6% of the total mass of the film, the biocide being distributed directly in the mass of the antimicrobial film. The antimicrobial film (1) has a more particular application for medical protection. The invention also relates to a composition and a manufacturing process which make it possible to obtain the antimicrobial film (1). Figure for the abstract: Fig. 1]

Description

Thermoplastic elastomer antimicrobial film, composition and method of manufacture for obtaining same

[The present invention falls within the field of polymeric materials and more particularly of thermoplastic films. The invention falls more specifically into the field of antimicrobial thermoplastic films.

In this context, the invention aims to provide an elastomeric thermoplastic film which can be used as antimicrobial protection, in particular in a medical, surgical, veterinary context, or more generally in the context of hygiene and health safety.

Indeed, there is a need to protect both patients and caregivers from healthcare-associated infections. With regard to the patient, an infection is said to be associated with healthcare when it occurs during the treatment of the patient by a healthcare professional. This infection can occur both at the start of care during the diagnostic phase and during the care itself: therapy, palliative care, preventive care, operative or post-operative care. Within the hospital environment, these infections are called “nosocomial”.

These infections can be linked to a bacterial germ from, for example, the family of Staphylococci, Salmonella, Listeria, etc. These infections can be problematic when the infectious germ is resistant or multi-resistant to antibiotics. The best known of these resistant germs is Staphylococcus aureus or Staphylococcus aureus . This type of infection can lead to serious complications which in extreme cases are likely to lead to amputation or death of the patient.

However, viruses can also be a source of healthcare-related infections and more particularly respiratory viruses such as influenza viruses, respiratory syncytial virus or coronaviruses. In the first twenty years of the 21st century, this last family is at the origin of three deadly epidemics: a first epidemic spread in 2003, it was linked to the SARS-CoV coronavirus, a second epidemic developed in 2012 and was due to the MERS-CoV coronavirus in 2012, finally recently a third epidemic declared itself at the end of 2019, at the beginning of 2020 following the spread of the SARS-CoV-2 coronavirus otherwise known as Covid-19. The latter was officially declared as a pandemic on March 12, 2020 by the WHO (World Health Organization).

This planetary health crisis has highlighted, in particular, the lack of protection of healthcare personnel against this highly contagious respiratory virus. Thus, many caregivers have been contaminated by Covid-19 while providing care to patients who are themselves infected.

Fungi or mycoses are also another type of germs that are likely to be a source of nosocomial infections. For information, fungi of the Aspergillus or Candida family are the most commonly identified as a source of healthcare-associated infections.

Healthcare-associated infections are problematic in many respects, first of all their large number. Normally, each year a country like France deplores approximately 1,000,000 patients who fall victim to a nosocomial infection, the severity of which varies. However, among this census, approximately 10,000 patients die from healthcare-associated infections.

From a health point of view, it is difficult to accept that a patient can be infected during his care pathway by a germ that is not directly related to the pathology which led him to follow care. . In addition, such an infection very often results in the prolongation of the patient's care pathway. In addition to the moral and physical harm suffered by some patients that there is no question of concealing, these healthcare-associated infections generate additional expenses both in terms of treatment by healthcare personnel and view of equipment and drugs. In a country like France, these expenses are covered by the healthcare reimbursement system, but this is not the case in most countries.

The modes of transmission of these infections are varied, they can be aerial in the case of tuberculosis, bacteria of the Legionella family or viruses such as SARS Cov-2, by a contaminated product such as blood derivatives, material contaminated medical device such as fiberscope etc. However, it is estimated that 80% of healthcare-associated infections are hand-borne, that is, transmitted by the hands.

Undoubtedly, the prevention of all the human and financial inconveniences that we have just exposed constitutes one of the major challenges of the healthcare system of our societies. However, one of the objectives of the present invention consists in reducing the risk of transmission of healthcare-associated infections for both patients and healthcare personnel.

Solutions for protecting patients or nursing staff already exist, thus documents EP 2 229 193, EP 0 136 900, EP 2 908 635, describe an opaque medical sheet which comprises a textile support impregnated with an antimicrobial preparation. The antimicrobial preparation may include a guanidine or bronopol antimicrobial agent. The textile support consists of woven meshes which comprise holes, consequently, the medical sheet obtained by impregnation has a non-planar surface which comprises hollows and/or recesses. These hollows and nooks favor the accumulation of microorganisms. In fact, the effectiveness of this type of medical sheet is not optimal and could even prove counter-use in the event of too great an accumulation of microorganisms on the surface of the impregnated textile.

Patent EP 0 721 024 describes an opaque three-layer film in which a central body is assembled below and above by two outer layers. The central body is discontinuous and consists of beads of biocide and adhesives. A first porous outer layer which is permeable to gas and/or water, it consists of a woven textile made of natural or synthetic fibres. The second outer layer is impermeable to air and water. These different layers are assembled with each other by lamination. This document proposes a complex multilayer film whose outer layers do not have antimicrobial properties. The microorganisms are trapped, passing through the porous layer, in the central body which contains the biocide. This multilayer film does not destroy microorganisms that settle on both sides. Furthermore, the complex structure of this multilayer film makes it expensive to produce.

In this context, the applicant has developed a technical solution capable of providing a biologically effective antimicrobial film and whose manufacturing constraints are restricted in order to accelerate production rates and reduce manufacturing costs.

The invention relates to an elastomeric thermoplastic antimicrobial film made of polyvinyl chloride or polyurethane or a mixture of these materials.

According to the invention, the antimicrobial film is characterized in that it is cast in its mass and incorporates a biocide comprised between 0.1 and 6% of the total mass of the film, the biocide being distributed directly in the mass, the antimicrobial film further has a thickness of between 50 μm to 300 μm and preferably the antimicrobial film has a thickness of between 100 μm to 200 μm.

The antimicrobial film is a medical protective device. It may be used as a medical sheet, medical protective film or even as an antibacterial protective cover.

Advantageously, the antimicrobial film is airtight and watertight, it can thus form a protective barrier against microorganisms.

According to a first embodiment of the invention, the antimicrobial film comprises at least two superposed and heat-sealed layers of an elastomeric thermoplastic material, at least one of the two layers comprises the biocide, preferably, the two layers incorporate a biocide in their mass.

According to a second embodiment of the invention, the antimicrobial film comprises at least three superimposed and heat-sealed layers of an elastomeric thermoplastic material, the film comprising a central body covered above and below by two outer layers, at least the one of the two outer layers incorporates a biocide in its mass, preferably, the two outer layers incorporate a biocide in their mass.

Advantageously, and unlike medical drapes of the state of the art, the antimicrobial film has a transparency of at least 70% to visible light, preferably it has a transparency of at least 90% to visible light. This feature allows the caregiver to perform medical procedures while the antimicrobial film is used as a medical sheet.

According to the invention, the antimicrobial film has an elongation at break of at least 150%, preferably it has an elongation at break of at least 180%. The antimicrobial film also has a tensile strength of at least 2kN/m, preferably the tensile strength is at least 4kN/m. Such mechanical properties contribute to reducing the risk of tearing of the antibacterial film. The film then forms a reliable protective barrier.

In addition, the antimicrobial film is dermo-compatible, so it can be used as medical protection. In particular, the antimicrobial film is particularly suitable for use as a medical sheet or as a protection of medical equipment against the transmission of infectious microorganisms.

The present invention also relates to a polymeric composition for preparing an antimicrobial film according to the invention.

• 1 à 6 % d’un biocide,
• 25 à 70 % d’au moins un solvant,
• 25 à 70 % d’au moins un précurseur de polyuréthane ou d’au moins un précurseur de polychlorure de vinyle,
• 1 à 5 % d’au moins un agent de contrôle.

This composition is characterized in that it comprises, in mass percentages relative to the total mass:

• 1 to 6% of a biocide,
• 25 to 70% of at least one solvent,
• 25 to 70% of at least one polyurethane precursor or at least one polyvinyl chloride precursor,
• 1 to 5% of at least one control agent.

With a view to casting the film using a coating process, the chosen biocide is an aprotic compound that is thermally stable at temperatures above 100°C, preferably the biocide is a compound that is thermally stable at temperatures above 150°C. Preferably, the biocide is a silver salt or a compound of isothiazole type.

• un solvant polaire aprotique de type acétate choisi parmi les solvants suivants : l’acétate de méthyle, acétate d’éthyle, acétate de propyle, acétate de butyle, acétate de pentyle, acétate d’hexyle, acétate d’heptyle, acétate d’octyle ou un mélange de ces composés ; ou
• un solvant polaire aprotique de type cétonique et choisi parmi les solvants suivants : di-méthyl-cétone, éthyl-méthyl-cétone, propyl-méthyl-cétone, butyl-méthyl-cétone, méthyl-butyl-cétone, méthyl-isobutyl-cetone, méthyl-pentyl-cétone, di-éthyl-cétone, éthyl-propyl-cétone, éthyl-butyl-cétone, éthyl-pentyl-cétone, di-propyl-cétone, butyl-propyl-cétone, pentyl-propyl-cétone, di-butyl-cétone, butyl-pentyl-cétone, ou un mélange de ces composés.

For a homogeneous solution of polymer precursors, the solvent comprises a dispersing solvent chosen from the following compounds:

• an aprotic polar solvent of acetate type chosen from the following solvents: methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, hexyl acetate, heptyl acetate, octyl acetate or a mixture of these compounds; Or
• an aprotic polar solvent of the ketone type and chosen from the following solvents: di-methyl-ketone, ethyl-methyl-ketone, propyl-methyl-ketone, butyl-methyl-ketone, methyl-butyl-ketone, methyl-isobutyl-ketone, methyl-pentyl-ketone, di-ethyl-ketone, ethyl-propyl-ketone, ethyl-butyl-ketone, ethyl-pentyl-ketone, di-propyl-ketone, butyl-propyl-ketone, pentyl-propyl-ketone, di- butyl-ketone, butyl-pentyl-ketone, or a mixture of these compounds.

• 1 à 6% de biocide ;
• 25 % à 45% comprend deux précurseurs de polychlorure de vinyle : une résine de chlorure de vinyle et un plastifiant polymérique, le ratio massique de chlorure de vinyle étant 1 :3 par rapport au plastifiant polymérique.
• 45 % à 70 % d’au moins un solvant ;
• 1 à 5 % d’un agent de contrôle constitué par un stabilisant thermique de type sel de baryum.

According to a variant of the polymeric composition of the invention, the composition comprises, in mass percentages relative to the total mass:

• 1 to 6% biocide;
• 25% to 45% comprises two polyvinyl chloride precursors: a vinyl chloride resin and a polymeric plasticizer, the mass ratio of vinyl chloride being 1:3 relative to the polymeric plasticizer.
• 45% to 70% of at least one solvent;
• 1 to 5% of a control agent consisting of a thermal stabilizer of the barium salt type.

This variant makes it possible to manufacture an antimicrobial polyvinyl chloride film in accordance with the invention. To this end, a vinyl chloride resin of the homopolymer type is used, the average molecular mass of which is between 150,000 g/mol and 250,000 g/mol. In parallel, the polymeric plasticizer can be a polymer of the polyadipate or polysebacate type.

• Un solvant d’hydrocarbure aromatique aprotique possédant 7 à 10 carbones choisi parmi la liste des composés suivants : toluène, xylène, m-xylène, p-xylène, éthylbenzène, mésitylène, durène, ou un mélange de ces composés ;
• Un solvant d’hydrocarbures aliphatiques dont la formule chimique possède entre 6 et 13 carbones ou un mélange de ces hydrocarbures aliphatiques.

According to the invention, the solvent may comprise a mixture of a dispersing solvent and a diluent solvent, the diluent solvent is also composed of a mixture of at least one compound of aromatic nature with at least one compound of aliphatic nature. in a 4:1 ratio, the diluent solvent is chosen from the following compounds:

• An aprotic aromatic hydrocarbon solvent having 7 to 10 carbons chosen from the list of the following compounds: toluene, xylene, m-xylene, p-xylene, ethylbenzene, mesitylene, durene, or a mixture of these compounds;
• A solvent of aliphatic hydrocarbons whose chemical formula has between 6 and 13 carbons or a mixture of these aliphatic hydrocarbons.

• 1 à 6% de biocide ;
• 10% à 35% d’un premier précurseur de polyuréthane comprenant un mélange d’un composé polyol à courtes chaines et d’un composé polyol à longues chaines selon un ratio du composé polyol à courtes chaines 1 :4 par rapport au composé polyol à longue chaines ;
• 15 % à 35% d’un second précurseur de polyuréthane comportant au moins un composé poly-isocyanate ;
• 25 % et 50 % d’au moins un solvant ; et
• 1 à 5 % d’un agent de contrôle comprenant un inhibiteur de polymérisation.

Another variant of the composition makes it possible to manufacture an antimicrobial polyurethane film. According to this variant, the polymer composition comprises, in mass percentages relative to the total mass:

• 1 to 6% biocide;
• 10% to 35% of a first polyurethane precursor comprising a mixture of a short-chain polyol compound and a long-chain polyol compound according to a ratio of the short-chain polyol compound 1:4 relative to the polyol compound at long chains;
• 15% to 35% of a second polyurethane precursor comprising at least one polyisocyanate compound;
• 25% and 50% of at least one solvent; And
• 1 to 5% of a control agent comprising a polymerization inhibitor.

According to this variant, the control agent further comprising a polymerization catalyst which is chelated by the polymerization inhibitor.

• une étape de préparation d’une composition polymérique conforme de l’invention qui intègre un biocide, la composition étant mélangée jusqu’à obtention d’une solution à l’état liquide homogène ;
• une étape de formation d’une première couche du film à l’état cohésif qui comporte :

• une opération d’enduction de ladite composition polymérique à l’état liquide sur un support solide,
• une opération de séchage et/ou de polymérisation de ladite composition polymérique enduite sur le support solide afin d’obtenir une première couche polymérique à l’état cohésif ;

• une étape de formation d’une deuxième couche du film à l’état cohésif qui comporte :

• une opération d’enduction de ladite composition polymérique sur une couche polymérique à l’état cohésif reposant directement ou indirectement sur le support, et
• une opération de séchage et/ou de polymérisation de ladite composition polymérique enduite à l’état liquide afin d’obtenir une deuxième couche polymérique à l’état cohésif permettant d’obtenir un film antimicrobien monobloc comprenant, d’une part, deux couches intégrant un biocide, et d’autre part, une épaisseur comprise entre 50 µm et 300 µm,.

Furthermore, the invention also relates to the process for manufacturing an antimicrobial film in accordance with the invention. The process is characterized in that it comprises:

• a step of preparing a polymeric composition in accordance with the invention which incorporates a biocide, the composition being mixed until a solution in the homogeneous liquid state is obtained;
• a step of forming a first layer of the film in the cohesive state which comprises:

• an operation of coating said polymeric composition in the liquid state on a solid support,
• an operation of drying and/or polymerization of said polymeric composition coated on the solid support in order to obtain a first polymeric layer in the cohesive state;

• a step of forming a second layer of the film in the cohesive state which comprises:

• an operation of coating said polymeric composition on a polymeric layer in the cohesive state resting directly or indirectly on the support, and
• an operation of drying and/or polymerization of said coated polymeric composition in the liquid state in order to obtain a second polymeric layer in the cohesive state making it possible to obtain a one-piece antimicrobial film comprising, on the one hand, two layers integrating a biocide, and on the other hand, a thickness of between 50 μm and 300 μm,.

• Une opération de préparation d’une deuxième composition polymérique incluant un matériau thermoplastique élastomère ou des précurseurs de ce matériaux, la deuxième composition étant mélangée jusqu’à obtention d’un solution homogène et transparente à l’état liquide,
• Une opération d’enduction de la deuxième composition polymérique sur la première couche à l’état cohésif,
• Une opération de séchage et/ou de polymérisation de la deuxième composition polymérique afin de la faire passer de l’état liquide à l’état cohésif formant ainsi une couche polymérique constituant le corps central solidaire de la couche à l’état cohésif sur laquelle il a été enduit.

In order to produce an antimicrobial film with at least three layers, the manufacturing method may comprise a step of forming a central body of the film which is constituted by at least one polymeric layer, the step of forming the central body comprising:

• An operation for preparing a second polymeric composition including an elastomeric thermoplastic material or precursors of this material, the second composition being mixed until a homogeneous and transparent solution in the liquid state is obtained,
• A coating operation of the second polymeric composition on the first layer in the cohesive state,
• An operation of drying and/or polymerization of the second polymeric composition in order to make it pass from the liquid state to the cohesive state, thus forming a polymeric layer constituting the central body integral with the layer in the cohesive state on which it was coated.

According to the invention, the step of forming the central body is interposed between the steps of forming the first and the second layer comprising the biocide.

The drying operations which are carried out within the framework of the manufacturing method of the invention are carried out by applying a temperature of between 70° C. and 200° C. for a period of less than 10 minutes.

Other features and advantages will appear in the following detailed description of two non-limiting embodiments of the invention illustrated by Figures 1 and 2 placed in the appendix and in which:

is a representation of a cross-section of an elastomeric thermoplastic film according to a first embodiment of the invention.

is a representation of a cross-section of an elastomeric thermoplastic film according to a second embodiment of the invention.

The invention relates to an antimicrobial film 1 having permanent antimicrobial properties. The antimicrobial film 1 is an elastomeric thermoplastic film. The antimicrobial properties of film 1 are of particular interest in the context of activities in which there is a high risk of transmission of a healthcare-associated infection. The use of antimicrobial film 1 as a medical and/or surgical drape is particularly effective in reducing the risk of transmission of infectious microorganisms for both the patient and the nursing staff. For example, in the case of hospitalization, the antimicrobial film 1 can be used as a blanket or sheet to cover the patient. The antimicrobial film 1 can be applied directly to the patient, or positioned like a tunnel above the patient using a support fixed to the bed or to the stretcher on which the patient is standing. It is also possible to use this film in the context of a medical environment dedicated to immunocompromised patients.

In this context, the antimicrobial film 1 then constitutes a physical barrier between the patient and the surrounding environment, thus protecting the patient from a hand-borne infection in particular. In addition, the antibacterial film 1 used as such also constitutes a physical barrier between the patient and the nursing staff, also protecting the nursing staff from a hand-borne infection from the patient.

In addition, the antimicrobial properties of film 1 make it possible to eliminate germs which could come into contact with thermoplastic film 1.

The antimicrobial film 1 is for single use. The film according to the invention meets the standard established by article 1, §1.1 of appendix IX of European Directive 93/42/EEC. As such, the antimicrobial film 1 can be used continuously for the same patient for a maximum period of thirty successive days.

The antimicrobial film 1 is made of thermoplastic elastomer. The elastomeric thermoplastic material can be chosen from the list of the following materials: polyvinyl chloride (PVC), polyurethane (PU) or a mixture of these materials.

According to the invention, the thermoplastic elastomer material has a mass percentage of between 50 to 99.9% relative to the total mass of the antimicrobial film 1.

In particular, the antimicrobial film 1 is cast in its mass. This contributes to producing a full and homogeneous film 1 without inclusion of air or fiber making it “impermeable” to air and water. Conversely, of a woven textile, the air impermeability of the film 1 according to the invention makes it possible to provide a bilateral barrier of reliable protection against microorganisms and in particular viruses whose size varies between 10 nm for the smallest and up to 400 nm for the largest.

Furthermore, the antimicrobial film 1 has a thickness of between 50 μm and 300 μm. Preferably, the antimicrobial film 1 has a thickness of between 100 μm to 200 μm.

The use of Antimicrobial Film 1 as a medical drape requires a film thickness between 100 µm and 300 µm. However, a film 1 which has a thickness of between 50 μm and 100 μm can be used as a protective film for electronic equipment in a medical environment such as a monitor, a keyboard, a touch or traditional screen, mobile telephones, etc. In practice, the antimicrobial film 1 is used as a disposable protective cover. The object to be protected is wrapped by a piece of film 1 which is then closed by heat welding or high frequency or ultrasonic welding.

The nature of the thermoplastic material(s) used and the thickness of the antimicrobial film 1 makes it possible to obtain specific properties. In particular, the characteristics of thickness and the materials chosen make it possible to obtain an antimicrobial film 1 which has properties of transparency to visible light. As known to those skilled in the art, visible light relates to electromagnetic waves with wavelengths between 400 nm and 800 nm. As a reminder, transparency designates the capacity of a material not to interact with a wave. According to the invention, the film 1 has a transparency of at least 70% to visible light, preferably the film 1 has a transparency of at least 90% to visible light. Advantageously, the translucent nature of the antimicrobial film 1 as defined, ensures the visibility of the patient and of the medical and/or surgical procedures, thus facilitating the care.

. Elasticity is another physical property that Antimicrobial Film 1 may possess. This property is also linked to the nature of the material and the thickness of the antibacterial film 1. Advantageously, the elastic character makes it possible to prevent any tearing of the film 1 and therefore any rupture of the protective barrier for the patient and/or the nursing staff. This is particularly useful when the nursing staff performs medical and/or surgical procedures to treat the patient covered with the antimicrobial film 1.

According to the invention, the antimicrobial film 1 has an elongation at break of at least 150%. Preferably, the antimicrobial film 1 has an elongation at break of at least 180%.

The tensile strength is also a property making it possible to reduce the risk of the antimicrobial film 1 tearing. According to the invention, the antimicrobial film 1 has a tensile strength of at least 2 kN/m, preferably the tensile strength of the antimicrobial film 1 is at least 4 kN/m.

The elongation at break and tensile strength measurements were carried out according to a method similar to the NF EN 14410 method using an “MTS criterion model 42” type dynamometer.

According to the invention, the antimicrobial film 1 integrates a biocide directly into the mass of the film 1. The biocide is thus distributed homogeneously and uniformly in the mass of the film 1. The chosen biocide is active both for bacterial, viral and again against fungi.

In particular, the chosen biocide is active according to the ISO 22196 standard on the following bacterial strains Staphylococcus aureus ( Staphylococcus aureus ), Methicillin-resistant Staphylococcus aureus (MRSA), Salmonella ( Salmonella enterica ), Listeria ( Listeria monocytogenes ), Escherichia coli and Pseudomonas aeruginosa .

For these purposes, the biocide may comprise silver nanoparticles or a compound from the isothiazole family. As an indication, silver nanoparticles can be complexed in the form of silver salts. These biocides comply with article 95(1) of the regulation on biocidal products corresponding to European Directive 98/8/EC. The European Chemicals Agency (ECHA) maintains a list of products that meet these standards. In this sense, other biocides in accordance with this regulation can be used in the context of the invention. This insofar as these biocides comply with the selection criteria of the invention (see the description of the composition below).

The antimicrobial film 1 derives its antimicrobial properties from the biocide integrated into its mass. More particularly, the mass percentage of the biocide is between 0.1 and 6% of the total mass of the antimicrobial film 1. Preferably, the mass percentage of biocide relative to the total mass of the film is less than 0.6%. Again preferably, the mass percentage of biocide relative to the total mass of the film is less than 0.3%.

Advantageously, according to this integration of biocide chosen according to the ISO 22196 standard, it is possible to obtain, on the surface of the antibacterial film 1, a logarithmic reduction of the bacterial colonies of between log 2 and log 5, i.e. a reduction of the bacterial colonies between 99% and 99.999 % on the surface of the antimicrobial film 1.

As illustrated in Figures 1 and 2, the antimicrobial film 1 comprises at least two layers 2, 3 superimposed and integral with each other. The two layers 2, 3 are heat-sealed. This makes it possible to avoid using an adhesive substance to maintain the cohesion of the film. Among these two layers 2, 3, at least one of them has a biocide integrated into its mass. In this example, the biocide is distributed homogeneously and uniformly in the mass of each layer 2, 3 which comprises biocide.

A first exemplary embodiment is illustrated in FIG. 1. In this example, the film comprises two superposed layers 2, 3 which each have a biocide integrated into the mass of the polymeric material which composes them. The outer surfaces of the two layers 2, 3 respectively define a face 4, 5 of the antimicrobial film 1.

It should be noted that the two superposed layers 2, 3 may have the same composition or else a different composition. This can be useful for imparting particular properties to one of the faces of the antimicrobial film 1.

Figure 2 illustrates a second embodiment of the invention. According to this example, the antimicrobial film 1 comprises a third layer 6. The third layer 6 is interposed between the other layers 2, 3. According to this example, the antimicrobial film 1 comprises three successive superposed layers 2, 3, 6.

The third layer 6 is thus considered as the central body of the antimicrobial film 1. The central body covered above and below by two outer layers 2, 3.

The nature of the central body can vary in order to obtain specific physical, mechanical, optical or elastic properties. However, in all cases the central body is made of an elastomeric thermoplastic material which is obtained by casting on a preformed layer 2, 3.

According to this embodiment, at least one of the two outer layers incorporates a biocide in its mass. Here, the two outer layers 2, 3 incorporate a biocide in their mass. In this example, the biocide is distributed homogeneously and uniformly in the mass of each outer layer 2, 3 which comprises biocide.

In general, as for the first embodiment, the three layers 2, 3, 6 are heat bonded together.

The two embodiments illustrated in Figures 1 and 2 can be used interchangeably. However, the example illustrated in FIG. 2 makes it possible, through the central body, to confer specific properties on the film 1 while retaining two faces 4, 5 that are biologically active against microorganisms.

In accordance with the invention, the two embodiments of the antimicrobial film 1 may possess the properties of transparency, elasticity and tensile strength. In addition, the antimicrobial film 1 is preferentially dermocompatible.

Dermatological tests were carried out on a sample of fifteen adult individuals aged 18 to 65. These tests consisted of applying a specimen of 4 cm² antibacterial film 1 to the skin of each individual for a period of 6 consecutive hours. A first visual control of the skin at the level of the site of the specimen was carried out during the removal of the specimen, a second control was carried out 30 minutes after the removal of the specimen. Finally, a third and final control was carried out 24 hours after the specimen was removed. For all fifteen individuals who participated, no sign of irritation was observed during the three controls.

Table 1 below illustrates several antimicrobial films 1 in accordance with the invention. Examples of antimicrobial film Number of layers Film thickness in µm Layer thickness loaded with biocide in µm Central body thickness in µm Film application AT 2 60 to 80 30 to 40 / Medical device protection B 2 100 to 140 50 to 70 / medical sheet VS 3 100 to 200 30 to 50 40 to 100 medical sheet D 3 200 to 300 50 to 75 150 to 200 medical sheet

Example A describes an antibacterial film 1 comprising two layers 2, 3 loaded with biocide, the total thickness of this film is less than 90 μm, such a film can be used as a protective film for equipment in a medical environment such as previously described. Preferably, this type of film is made of PVC.

Conversely, examples B, C and D are antibacterial films 1 with two layers 2, 3 (example B) or three layers 2, 3, 6 (examples C and D) whose total thickness is greater than or equal to 100 µm. These three films are more particularly used as a sheet as described above.

As mentioned above, the antimicrobial film 1 is obtained by at least two coatings of a polymer composition for preparing the film.

• 1 à 6 % d’un biocide,
• 25 à 70 % d’un au moins solvant,
• 25 à 70 % d’au moins un précurseur de polyuréthane ou d’au moins un précurseur de polychlorure de vinyle, et
• 1 à 5 % d’au moins un agent de contrôle.

In fact, the invention also relates to a polymeric composition for the preparation of the antimicrobial film 1. This polymeric composition according to the invention comprises, in mass percentages relative to the total mass:

• 1 to 6% of a biocide,
• 25 to 70% of at least one solvent,
• 25 to 70% of at least one polyurethane precursor or at least one polyvinyl chloride precursor, and
• 1 to 5% of at least one control agent.

• 1 à 6 % d ’un biocide,
• 25 à 70 % d’au moins un solvant,
• 25 à 70 % d’au moins un précurseur de polyuréthane ou d’au moins un précurseur de polychlorure de vinyle,
• 1 à 5 % d’au moins un agent de contrôle.

The polymer composition according to the invention consists in mass percentages relative to the total mass of:

• 1 to 6% of a biocide,
• 25 to 70% of at least one solvent,
• 25 to 70% of at least one polyurethane precursor or at least one polyvinyl chloride precursor,
• 1 to 5% of at least one control agent.

The polymeric composition incorporates a biocide in order to give the antibacterial film 1 its antimicrobial properties. Preferably, the biocide is an aprotic compound thermally stable at temperatures above 100°C, preferably, the biocide is a compound thermally stable at temperatures above 150°C. This makes it possible to coat the composition on a support and to evaporate the solvent in order to obtain a layer 2, 3 of the antimicrobial film 1.

The biocide according to the invention may comprise silver nanoparticles. Preferably, the silver nanoparticles are complexed in the form of silver salts. As an indication, the biocide can be chosen from the list of the following silver salts: silver nitrate, silver silicates, silver thiosulphate, or a mixture of these compounds.

Silver nanoparticles can also be supported by zeolite complexes of silver and zinc.

Isothiazole type compounds are also stable biocides at the temperatures previously discussed. The biocide can thus comprise, in combination with silver nanoparticles or silver salts, compounds of the isothiazole type. According to the invention, the biocide may comprise a compound of isothiazole type chosen from the following list: 2-butyl-benzo[d]isothiazol-3-one (BBIT), 2-methyl-1,2-benzothiazol-3(2H) -one (MBIT), 2-methyl-2H-isothiazol-3-one (MIT), 2-octyl-2H-isothiazol-3-one (OIT), 5-Chloro-2-methyl-2H-isothiazol-3- one (CIT), 5-chloro-2-methyl-2H-isothiazol-3-one (CMIT) or a mixture of these compounds.

The polymer composition according to the invention comprises a solvent comprising at least one dispersing solvent. In this example, it is preferable to use an aprotic polar solvent which makes it possible to optimize the solvation of the polymer precursors integrated into the composition. The solvents of the polymeric composition are important, the composition must be in the liquid state to allow a coating operation. For this purpose, the viscosity of the composition must be between 200 and 10,000 mPa/s.

Their aprotic character makes it possible in particular to prevent a polyurethane precursor such as an isocyanate compound from reacting with the solvent.

According to the invention, the aprotic polar solvent can be of the acetate type and chosen from the following solvents: methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, hexyl acetate, acetate of heptyl, octyl acetate or a mixture of these compounds.

Alternatively or in combination, the aprotic polar solvent can be of the ketone type and chosen from the following solvents: di-methyl-ketone, ethyl-methyl-ketone, propyl-methyl-ketone, butyl-methyl-ketone, methyl-butyl -ketone, methyl-isobutyl-ketone, methyl-pentyl-ketone, di-ethyl-ketone, ethyl-propyl-ketone, ethyl-butyl-ketone, ethyl-pentyl-ketone, di-propyl-ketone, butyl-propyl-ketone , pentyl-propyl-ketone, di-butyl-ketone, butyl-pentyl-ketone, or a mixture of these compounds.

According to the invention, there are two embodiment variants of the polymeric composition. A first variant uses polyurethane precursors, while the second variant uses polyvinyl chloride (PVC) precursors. In fact, it is possible to obtain an antibacterial film 1 in PVC or polyurethane or even in a mixture of these two materials.

• 1 à 6% de biocide ;
• 10% à 35% d’un premier précurseur de polyuréthane comprenant un mélange d’un composé polyol à courtes chaines et d’un composé polyol à longues chaines selon un ratio du composé polyol à courtes chaines 1 :4 par rapport au composé polyol à longue chaines ;
• 15 % à 35 % d’un second précurseur de polyuréthane comportant au moins un composé poly-isocyanate ;
• 25 % et 50 % d’au moins un solvant ;
• 1 à 5 % d’un agent de contrôle comprenant un inhibiteur de polymérisation.

The first variant makes it possible to obtain an antibacterial film 1 made of polyurethane. According to this first variant, the polymer composition more particularly comprises, in mass percentages relative to the total mass:

• 1 to 6% biocide;
• 10% to 35% of a first polyurethane precursor comprising a mixture of a short-chain polyol compound and a long-chain polyol compound according to a ratio of the short-chain polyol compound 1:4 relative to the polyol compound at long chains;
• 15% to 35% of a second polyurethane precursor comprising at least one polyisocyanate compound;
• 25% and 50% of at least one solvent;
• 1 to 5% of a control agent comprising a polymerization inhibitor.

• 1 à 6% de biocide ;
• 10% à 35% d’un premier précurseur de polyuréthane comprenant un mélange d’un composé polyol à courtes chaines et d’un composé polyol à longues chaines selon un ratio du composé polyol à courtes chaines 1 :4 par rapport au composé polyol à longue chaines ;
• 15 % à 35 % d’un second précurseur de polyuréthane comportant au moins un composé poly-isocyanate ;
• 25 % et 50 % d’au moins un solvant ;
• 1 à 5 % d’un agent de contrôle comprenant un inhibiteur de polymérisation.

Preferably, the first variant of the polymer composition consists of mass percentages relative to the total mass:

• 1 to 6% biocide;
• 10% to 35% of a first polyurethane precursor comprising a mixture of a short-chain polyol compound and a long-chain polyol compound according to a ratio of the short-chain polyol compound 1:4 relative to the polyol compound at long chains;
• 15% to 35% of a second polyurethane precursor comprising at least one polyisocyanate compound;
• 25% and 50% of at least one solvent;
• 1 to 5% of a control agent comprising a polymerization inhibitor.

The first variant of the composition comprises a mixture of short- and long-chain polyols which makes it possible to control the mechanical properties of the antimicrobial film 1.

The 1:4 ratio of short-chain polyols to long-chain polyols makes it possible to obtain an antimicrobial film 1 which has the elastic properties described above.

In a known manner, compounds of the short-chain polyol type stiffen the structure of the polyurethane layer which will be formed. Conversely, compounds of the polyol type with long chains soften the structure of the polyurethane layer which results from their polymerization.

According to the invention, a compound of short-chain polyol type preferably comprises a molar mass of less than 200 g/mol, and may in particular be chosen from the list of compounds of the following saturated aliphatic polyol type: 2-methyl-propanediol, 2 ,2-dimethyl-propanediol, propane diol, ethane diol, 1,4-butane diol, 1,3-butanediol, 1,2-butane diol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol , 1,3-hexanediol, 1,2-hexanediol, 2-methyl hexane diol, 3-methyl-hexanediol, 4-methyl-hexanediol, 2,2-dimethyl hexanediol, 3,3-dimethyl-hexanediol, 4,4- dimethyl-hexanediol, 2,3-dimethyl-hexanediol, 2,4-dimethyl-hexanediol, 2,5-dimethyl hexanediol, 2,6-dimethyl-hexanediol, 3,4-dimethyl-hexanediol, 3,5-dimethyl-hexanediol , 3,6-dimethyl-hexanediol, 4,5-dimethyl hexanediol, 4,6-dimethyl-hexanediol ethylene glycol, 1,2-pentandiol, 1,3-pentandiol, 1,4-pentandiol, 1,5-pentandiol, 2,3-pentandiol, 2,4-pentandiol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol.

At the same time, a compound of the long-chain polyol type preferably comprises a molar mass greater than 800 g/mol and may in particular be chosen from the list of the following polymer families: polycarbonate polyol, polyether polyol, polyester polyol, polyurethane polyol, vinyl polyol, polyacrylate polyol, as well as families derived from several types such as polyester-carbonate polyols or polyols derived from plant chemistry such as glycerol which can be obtained by hydrolysis of triglycerides or derived from glucose such as than isosorbide or sorbitol.

In order to obtain the formation of polyurethane constituting a layer 2, 3 of the antibacterial film 1, the polymer composition according to the invention also comprises a compound of isocyanate type and more particularly of polyisocyanate type.

In known manner, a compound of polyisocyanate type is a polyurethane precursor suitable for reacting with an alcohol function so as to form a polymer having a urethane unit.

According to the first variant of the composition, the compound of poly-isocyanate type can in particular be chosen from di- and/or tri-functional commercial products such as a 4,4'-methylene bis(cyclohexyl isocyanate) oligomer commonly called "H12MDI". , a hexane diisocyanate oligomer commonly referred to as “HDI” or even an isophorone diisocyanate oligomer commonly referred to as “IPDI”.

In order to obtain a skin-compatible antibacterial film 1, the composition comprises a mixture of polyols and the isocyanate compound(s) in stoichiometric proportion. This prevents the antibacterial film 1 from containing too many free monomers which could irritate the patient's skin.

The first variant of the composition comprises a control agent comprising a polymerization inhibitor. The polymerization inhibitor keeps the composition in the liquid state for a time so as to carry out a homogeneous coating of the polymer composition according to the first variant.

. Preferably, the polymerization inhibitor blocks the polymerization reaction by complexing a polymerization catalyst which is also included in the composition.

In this context, the polymerization catalyst can be formed by one or more metal catalysts, for example of the Dibutyltindilaureate (DBTL) or Dioctyltindilaureate (DOTL) type. However, it is preferable to use one or more organometallic catalysts which can be based on tin, aluminum, zirconium, cobalt, bismuth, or zinc. Indeed, organometallic catalysts allow a faster reaction than the aforementioned metal catalysts, they make it possible to ensure complete polymerization at the end of the manufacturing line.

The polymerization inhibitor is formed by a chelating agent, which is suitable for carrying out a chelate of the polymerization catalyst. With this in mind, the chelating agent is introduced in excess relative to the polymerization catalyst.

In this example, the chelating agent is a diketone type compound with a high vapor pressure of 1.02 Kpa at 25°C. This characteristic gives the chelating agent a volatile nature. Such a diketone compound can in particular be chosen from the list of the following compounds: ethyl acetoacetate, 3-ethyl-2,4-pentandione, 1,1,1-trifluoro-2,4-pentanedione, triacetyl methane, 2,4-pentandione , 6-methyl-2,4-heptadione,2,2,6,6-tetramethyl-3,5-heptadione,1-benzoyl acetone. The polymerization inhibitor may consist of one of these diketone compounds or a mixture of these compounds.

In addition, solventizing the composition with an aprotic polar solvent with a high vapor pressure, that is to say, a compound which has a high capacity for evaporation when it rises in temperature, makes it possible to easily eliminate the solvent by evaporation. Here, the solvent used has a vapor pressure between 10 and 25 kPa at 25°C.

In this way, it is possible to obtain a polymer composition in which the mass percentage of solvent is less than 50% relative to the total mass of the polymer composition and preferably it is possible to use a mass percentage of solvent of less than 35 % of the total mass of the polymer composition.

Table 2 below presents four examples of composition according to the first variant of the invention. Compound Example 1 Example 2 Example 3 Example 4 Silver nitrate in % by weight 3.5 1 2.5 4.5 1,2-butane diol in % by weight 5 6.5 5.7 6.1 polyacrylate polyol in % by weight 20 26 22.8 24.4 Isophorone diisocyanate oligomer
in % by weight 26 35 31.5 33.3 Dibutyltindilaureate
in % by weight 0.2 0.5 0.4 1 2,4-pentandione
in % by weight 1 1 1.2 3 methyl-pentyl-ketone
in % by mass 44.3 30 35.9 27.7 Total in % 100 100 100 100

• 1 à 6% de biocide ;
• 25 % à 45% comprend deux précurseurs de polychlorure de vinyle : une résine de chlorure de vinyle et un plastifiant polymérique, le ratio massique de chlorure de vinyle étant 3 :1 par rapport au plastifiant polymérique ;
• 50 % et 70 % d’au moins un solvant ;
• 1 à 5 % d’un agent de contrôle constitué par un stabilisant thermique de type sel de baryum.

In addition, the second variant of the polymeric composition comprises two polyvinyl chloride precursors. According to the invention, the second variant of the polymeric composition comprises, in mass percentages relative to the total mass:

• 1 to 6% biocide;
• 25% to 45% comprises two polyvinyl chloride precursors: a vinyl chloride resin and a polymeric plasticizer, the mass ratio of vinyl chloride being 3:1 with respect to the polymeric plasticizer;
• 50% and 70% of at least one solvent;
• 1 to 5% of a control agent consisting of a thermal stabilizer of the barium salt type.

• 1 à 6% de biocide ;
• 25 % à 45% comprend deux précurseurs de polychlorure de vinyle : une résine de chlorure de vinyle et un plastifiant polymérique, le ratio massique de chlorure de vinyle étant 3:1 par rapport au plastifiant polymérique ;
• 50 % et 70 % d’au moins un solvant ; et
• 1 à 5 % d’un agent de contrôle constitué par un stabilisant thermique de type sel de baryum.

Preferably, the second variant of the polymeric composition consists, in mass percentages relative to the total mass, of:

• 1 to 6% biocide;
• 25% to 45% comprises two polyvinyl chloride precursors: a vinyl chloride resin and a polymeric plasticizer, the mass ratio of vinyl chloride being 3:1 relative to the polymeric plasticizer;
• 50% and 70% of at least one solvent; And
• 1 to 5% of a control agent consisting of a thermal stabilizer of the barium salt type.

The polymer composition preferably comprises a polyvinyl chloride (PVC) homopolymer resin. PVC homopolymer resin has an average molecular weight between 150,000 and 250,000 g/mol. The average molecular weight can also be expressed in K-Werts, here the PVC resin is in the form of a powder which has a K-Werts of between 60 and 90. Preferably, the PVC resin used comprises a K- Werts between 70 and 80.

As is known, PVC is not an irritating material for the skin. In fact, it is preferable to choose a PVC resin which has a level of residual monomers of less than 1 ppm. This contributes to obtaining a skin-compatible antimicrobial film 1 .

In known manner, the plasticizer improves the thermal resistance and the light stability of the PVC. In addition, the plasticizer increases the elasticity of PVC at low temperatures. In practice, the plasticizer is used in a ratio of 35 PCR, i.e. 35 g of plasticizer for 100 g of vinyl chloride resin. According to the invention, the plasticizer is introduced into the composition according to a mass ratio of 1 to 3 with respect to the vinyl chloride resin.

Preferably, the plasticizer is a polar polymer. The plasticizer can be chosen from the family of polyadipades or polysebacates. Preferably, the plasticizer has an average molar mass of between 2000 g/mole to 12,000 g/mole.

Glycol polyadipate meets these criteria, as do the following commercial products: Palamoll 652 ^® , Edenol 1233 ^® , Santicizer 430 ^® .

This helps ensure good cohesion between the plasticizer and the vinyl chloride resin. This also promotes the solvation of the plasticizer in a polar solvent such as the dispersing solvents described previously.

For the same reasons as PVC resin, the plasticizer is preferably chosen when it has a level of residual monomers of less than 1 ppm.

The second variant of the polymeric composition preferably comprises a comprising a mixture of a dispersing solvent and a diluting solvent. The solvent mixture comprises a mass percentage of dispersing solvent of less than 10% relative to the total mass of solvent.

The diluent solvent may itself comprise a mixture of at least one compound of an aromatic nature with at least one compound of an aliphatic nature. This mixture is preferably produced according to a 4:1 ratio of compound of aromatic nature.

Preferably, the aromatic hydrocarbon solvent is chosen aprotic. This avoids any parasitic reaction with the PVC resin or with the plasticizer.

The aromatic hydrocarbon solvent has a carbon number of between 7 and 10. Preferably, the aromatic hydrocarbon solvent can be chosen from the list of the following compounds: toluene, xylene, m-xylene, p-xylene, ethylbenzene, mesitylene, durene, or a mixture of these compounds.

According to the invention, it is possible to use an aliphatic hydrocarbon solvent which has a chemical formula comprising 6 and 13 carbons. A solvent of aliphatic hydrocarbons whose chemical formula has between 6 and 13 carbons or a mixture of these aliphatic hydrocarbons.

The aliphatic hydrocarbon solvent can be chosen from the list of these following compounds: hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, cyclohexene, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, methyl-cyclohexane, cubane , or a mixture of these compounds.

It is also possible to use a petroleum fraction of the ^Solvesso® 100 or ^HIsol® 100 type as solvent for aliphatic hydrocarbons.

In this second variant of the invention, the heat stabilizer of the barium salt type helps to prevent the PVC resin from deteriorating when the polymer composition is exposed to a heat source to eliminate the solvent.

The barium salt can be chosen from the list of the following commercial compounds: Baerostab ^® UBZ 674 X RF, Baerostab ^® UBZ 660-4 RF, Mark ^® 4821, Mark ^® 4864, Mark ^® RFD, LASTAB ^® DC 1595.

Table 3 below presents four examples of composition according to the second variant of the invention. Compound Example 5 Example 6 Example 7 Example 8 Silver nitrate in % by weight 1.5 2 3 3.5 PVC homopolymer in % by weight 30 24 33 27 Glycol polyadipate in % by weight 10 8 11 9 methyl-butyl-ketone in % by weight 2,825 3.15 2.6 2.95 p-xylene
in % by weight 42.94 47.88 39.52 44.84 heptane
in % by mass 10,735 11.97 9.88 11.21 barium salt 2 3 1 1.5 Total in % 100 100 100 100

The invention also relates to a process for manufacturing the antimicrobial film 1 which uses the polymeric composition according to the invention.

As we have indicated, the antimicrobial film 1 is cast in its mass by a coating of said polymeric composition in the liquid state. Although the antimicrobial film 1 according to the invention is in one piece, it comprises at least two polymeric layers 2, 3, 6 as we have described.

The choice of the coating technique to form the layers 2, 3, 6 of the antimicrobial film 1 makes it possible to work at a lower temperature than in the context of forming a polymeric film by extrusion. According to the invention, the polymer composition is brought to a temperature of between 80° C. and 200° C., whereas the extrusion technique applies a temperature higher than the melting temperature of the extruded material, i.e. 150° C. for PVC and 250°C for polyurethane. However, in practice during an extrusion process, materials are often subjected to temperatures above 200°C or even above 250°C. In fact, the composition presents fewer constraints with regard to the thermal sensitivity of the compounds such as the biocide.

In practice, said polymeric composition is cast on a solid support of a ten meter long oven. However, it is difficult to produce a polymeric layer which has a thickness greater than 70 μm on this type of material. In this context, the applicant has opted for a method of manufacturing an antimicrobial film 1 which comprises at least two polymeric layers 2, 3, 6 superimposed. By superimposed, it should be understood that the polymeric layers 2, 3, 6 are cast on top of each other.

According to this principle, the process for manufacturing the antimicrobial film 1 according to the invention comprises a step of preparing a polymeric composition described above which incorporates a biocide. The various compounds of said polymeric composition are preferably mixed with vigorous stirring. The polymeric composition is mixed until a homogeneous and transparent liquid state solution is obtained.

The manufacturing process includes a step of forming a first layer 2, 3 of the film 1 in the cohesive state. This step includes an operation of coating said polymeric composition in the liquid state on a solid support. In this example the solid support is flat and directly integrated into an industrial furnace which can measure 10 meters long by 2 meters wide and beyond these dimensions. The coating operation is accompanied by an operation for spreading the polymeric composition so as to form a smooth layer whose thickness is between 40 μm and 120 μm. Indeed, depending on the mass percentage of the solvent relative to the total mass of polymeric composition, a dry polymeric layer 2, 3, 6 can lose 20 to 50% of the thickness of the wet layer (charged with solvent) which has been spread out.

The step of forming the first layer also involves an operation of drying and/or polymerization of said polymeric composition coated on the solid support in order to obtain a first polymeric layer in the cohesive state. This drying operation is carried out by applying a temperature between 70°C and 200°C for a period of less than 10 minutes.

We speak of polymerization when the polymer composition comprises polyurethane precursors as described in the first variant of polymer composition. In this case, the polymerization starts following the evaporation of the polymerization inhibitor, which begins as soon as the temperature rises in the polymer composition spread on a solid support or on a polymer layer in the cohesive state. In practice, the solvent used has a higher vapor pressure and a lower boiling point than the polymerization inhibitor, so it is likely that the solvent has evaporated before the start of the polymerization reaction.

Subsequently, the polymerization of the polyurethane is thermocatalyzed by the heat applied to the polymeric composition.

Following the drying operation, the first layer 2, 3 is in the cohesive state and rests directly on the oven support. A second polymeric layer 2, 3, 6 is then cast on the surface of the first layer 2, 3.

In this context, the manufacturing process includes a step of forming a second layer 2, 3 of the film 1 in the cohesive state. More specifically, this step comprises an operation of coating said polymeric composition on a polymeric layer 2, 3, 6 in the cohesive state already formed and resting directly or indirectly on the support.

Once the second coating of the polymer composition has taken place, a drying and/or polymerization operation is carried out so that said coated polymer composition changes from the liquid state to the cohesive state. The second polymeric layer 2, 3 is secured to the first polymeric layer 2, 3 by thermal bonding during the rise in temperature of the oven.

The antimicrobial film 1 obtained is in one piece and comprises two layers 2, 3 integrating a biocide. The thickness of the antimicrobial film 1 is between 50 µm and 300 µm.

As we mentioned previously, it is difficult to obtain a polymeric layer greater than 75 μm by induction under the material conditions described. Thus, when it is desired to obtain an antimicrobial film 1 whose thickness is greater than 140 μm, a third coating of a polymeric composition is carried out.

For economic reasons and as the biocide does not migrate from the core of the polymeric layer to its surface, the third coating aims to provide a central body which is not loaded with biocide as illustrated in figure 2.

To this end, the manufacturing process includes a step of forming a central body of the film 1 which consists of a polymeric layer 6. Here, the step of forming the central body is interposed between the steps of forming the first and the second layer 2, 3 comprising biocide.

According to the invention, the step of forming the central body comprises an operation of preparing a second polymeric composition including an elastomeric thermoplastic material or precursors of this material.

• 25 à 70 % d’au moins un solvant,
• 25 à 70 % d’au moins un précurseur de polyuréthane ou d’au moins un précurseur de polychlorure de vinyle,
• 1 à 5 % d’au moins un agent de contrôle.

The polymeric composition of the central body according to the invention comprises, in mass percentages relative to the total mass:

• 25 to 70% of at least one solvent,
• 25 to 70% of at least one polyurethane precursor or at least one polyvinyl chloride precursor,
• 1 to 5% of at least one control agent.

• 25 à 70 % d’au moins un solvant,
• 25 à 70 % d’au moins un précurseur de polyuréthane ou d’au moins un précurseur de polychlorure de vinyle,
• 1 à 5 % d’au moins un agent de contrôle.

The polymeric composition of the central body according to the invention consists in mass percentages relative to the total mass of:

• 25 to 70% of at least one solvent,
• 25 to 70% of at least one polyurethane precursor or at least one polyvinyl chloride precursor,
• 1 to 5% of at least one control agent.

The composition of the central body is also mixed until a homogeneous and transparent solution in the liquid state is obtained.

It should be noted that it is possible to vary the natures or the proportions of the polyurethane or polyvinyl chloride precursors as described above for the polymeric composition incorporating the biocide. This makes it possible to vary the mechanical properties of the central body such as the elasticity.

The step of forming the central body comprises an operation of coating the polymeric composition of the central body on the first layer 2, 3 in the cohesive state which rests on the support of the oven.

-The step of forming the central body ends with a drying and/or polymerization operation in order to change the second polymeric composition of the central body from the liquid state to the cohesive state, thus forming a polymeric layer 6 constituting the central body.

The central body is of course secured to the layer 2, 3 in the cohesive state on which it was cast. According to this configuration, the central body rests indirectly on the oven support.

According to this embodiment, the second layer 2, 3 loaded with biocide is cast on the central body in the cohesive state.

It should be noted that depending on the thickness that one wishes to give to the central body, it is possible to carry out several casting operations superimposed on each other. As an indication, if one wishes to obtain a central body 140 µm thick, two castings of 70 µm thickness can be made.

Before each coating operation, the manufacturing process may also include an operation of filtration of the polymer composition in the liquid state. This makes it possible to eliminate any particles, aggregates or dust present in the polymeric composition which could be detrimental to the quality of the polymeric layer which must be perfectly transparent and flawless. This operation of filtration of the polymeric composition can be carried out by filtration on a cloth having a porosity of between 20 μm and 80 μm.

Furthermore, each coating operation is associated with an operation of spreading the polymer composition on the surface of the flat solid support or of a polymer layer in the cohesive state. This spreading operation is performed at the Mayer bar. As is known, the Mayer bar is chosen according to the index of its thread. Thus, the quantity of the polymeric composition deposited on the support is determined according to the thickness of the polymeric layer which it is desired to obtain and the index of the Mayer bar.

The polymeric composition generally loses between 20% and 50% of its thickness when it passes from the liquid state to the cohesive state. In fact, to obtain a polymeric layer 2, 6 comprised between 30 μm and 60 μm thick, in practice, the polymer composition is spread in the liquid state to a thickness comprised 40 μm and 120 μm.

It is also possible to carry out the coating and spreading with an air knife, knife on cylinder, floating knife, cylinder on cylinder, three or four cylinders direct or reverse, the Mayer bar, the coma bar or methods usually used by printers such as flexography, heliography, etc.

When the manufacture of the antibacterial film 1 is finished, the film 1 is cooled before being rolled up in the form of a reel of 2,000 linear meters.

When the antimicrobial film 1 is intended for use in the context of an operating theatre, the manufacturing process and the packaging of the antimicrobial film 1 can take place in a room whose atmosphere is controlled, such as a clean room.]

Claims (22)

Thermoplastic elastomer antimicrobial film (1) made of polyvinyl chloride or polyurethane or a mixture of these materials, characterized in that it is cast in its mass and incorporates a biocide comprised between 0.1 and 6% of the total mass of the film , the biocide being distributed directly in the mass of the antimicrobial film, the antimicrobial film (1) also has a thickness of between 50 μm and 300 μm, preferably the antimicrobial film has a thickness of between 100 μm and 200 μm. Antimicrobial film (1) according to claim 1, characterized in that it comprises at least two layers (2, 3, 6) superimposed and heat-sealed of an elastomeric thermoplastic material, at least one of the two layers (2, 3 ) comprises the biocide, preferably, the two layers (2, 3) incorporate a biocide in their mass. Antimicrobial film (1) according to Claim 1, characterized in that it comprises at least three layers (2, 3, 6) superimposed and heat-sealed of an elastomeric thermoplastic material, the film (1) comprising a central body covered above and below by two outer layers (2, 3), at least one of the two outer layers (2, 3) incorporates a biocide in its mass, preferably, the two outer layers (2, 3, 6) incorporate a biocide in their mass. Antimicrobial film (1) according to one of Claims 1 to 3, characterized in that it is airtight and watertight. Antimicrobial film (1) according to one of Claims 1 to 4, characterized in that it has a transparency of at least 70% to visible light, preferably it has a transparency of at least 90% to visible light. Antimicrobial film (1) according to one of Claims 1 to 5, characterized in that it has an elongation at break of at least 150%, preferably it has an elongation at break of at least 180%. Antimicrobial film (1) according to one of Claims 1 to 6, characterized in that it has a tensile strength of at least 2 kN/m, preferably the tensile strength is at least 4 kN /m. Antimicrobial film (1) according to one of Claims 1 to 7, characterized in that it is dermo-compatible. Antimicrobial film (1) according to one of Claims 1 to 8, for use as a medical drape or as protection of medical equipment against the transmission of infectious microorganisms. Polymeric composition for the preparation of an antimicrobial film (1) according to one of Claims 1 to 9, characterized in that it comprises, in mass percentages relative to the total mass:

• 1 to 6% of a biocide,
• 25 to 70% of at least one solvent,
• 25 to 70% of at least one polyurethane precursor or at least one polyvinyl chloride precursor,
• 1 to 5% of at least one control agent.

Polymeric composition according to Claim 10, the biocide being an aprotic compound thermally stable at temperatures above 100°C, preferably the biocide is a compound thermally stable at temperatures above 150°C. Polymeric composition according to one of Claims 10 and 11, the biocide being a silver salt or a compound of isothiazole type. Polymeric composition according to one of Claims 10 to 12, characterized in that the solvent comprises a dispersing solvent chosen from the following compounds:

• an aprotic polar solvent of acetate type chosen from the following solvents: methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, hexyl acetate, heptyl acetate, octyl acetate or a mixture of these compounds; Or
• an aportic polar solvent of the ketone type and chosen from the following solvents: di-methyl-ketone, ethyl-methyl-ketone, propyl-methyl-ketone, butyl-methyl-ketone, methyl-butyl-ketone, methyl-isobutyl-ketone, methyl-pentyl-ketone, di-ethyl-ketone, ethyl-propyl-ketone, ethyl-butyl-ketone, ethyl-pentyl-ketone, di-propyl-ketone, butyl-propyl-ketone, pentyl-propyl-ketone, di- butyl-ketone, butyl-pentyl-ketone, or a mixture of these compounds.

Polymeric composition according to one of Claims 10 to 13, in that it comprises, in mass percentages relative to the total mass:

• 1 to 6% biocide;
• 25% to 45% comprises two polyvinyl chloride precursors: a vinyl chloride resin and a polymeric plasticizer, the mass ratio of vinyl chloride being 1:3 relative to the polymeric plasticizer.
• 45% to 70% of at least one solvent;
• 1 to 5% of a control agent consisting of a thermal stabilizer of the barium salt type.

Polymeric composition according to Claim 14, the vinyl chloride resin being a homopolymer with a molecular weight of between 150,000 g/mol and 250,000 g/mol, this molecular weight being an average molecular weight. Polymeric composition according to one of Claims 14 and 15, the polymeric plasticizer is of the polyadipate or polysebacate type. Polymeric composition according to one of Claims 14 to 16, the solvent comprising a mixture of a dispersing solvent and a diluent solvent, the diluent solvent is also composed of a mixture of at least one compound of aromatic nature with at at least one compound of aliphatic nature in a 4:1 ratio, the diluent solvent being chosen from the following compounds:

• An aprotic aromatic hydrocarbon solvent having 7 to 10 carbons chosen from the list of the following compounds:

toluene, xylene, m-xylene, p-xylene, ethylbenzene, mesitylene, durene, or a mixture of these compounds;

• A solvent of aliphatic hydrocarbons whose chemical formula has between 6 and 13 carbons or a mixture of these aliphatic hydrocarbons.

Polymeric composition according to one of Claims 10 to 13, in that it comprises, in mass percentages relative to the total mass:

• 1 to 6% biocide;
• 10% to 35% of a first polyurethane precursor comprising a mixture of a short-chain polyol compound and a long-chain polyol compound according to a ratio of the short-chain polyol compound 1:4 relative to the polyol compound at long chains;
• 15% to 35% of a second polyurethane precursor comprising at least one polyisocyanate compound;
• 25% and 50% of at least one solvent;
• 1 to 5% of a control agent comprising a polymerization inhibitor.

Polymer composition according to claim 18, the control agent further comprising a polymerization catalyst which is chelated by the polymerization inhibitor. Process for manufacturing an antimicrobial film according to one of Claims 1 to 9, characterized in that it comprises:

• a step of preparing a polymeric composition according to one of claims 10 to 19 which incorporates a biocide, the composition being mixed until a solution in the homogeneous and transparent liquid state is obtained;
• a step of forming a first layer (2, 3) of the film (1) in the cohesive state which comprises:

• an operation of coating said polymeric composition in the liquid state on a solid support, and
• an operation of drying and/or polymerization of said polymeric composition coated on the solid support in order to obtain a first polymeric layer in the cohesive state;

• a step of forming a second layer (2, 3) of the film (1) in the cohesive state which comprises:

• an operation of coating said polymeric composition on a polymeric layer (2, 3, 6) in the cohesive state resting directly or indirectly on the support, and
• an operation of drying and/or polymerization of said polymeric composition coated in the liquid state in order to obtain a second polymeric layer in the cohesive state making it possible to obtain a one-piece antimicrobial film (1) comprising, on the one hand, two layers (2, 3) integrating a biocide, and on the other hand, a thickness of between 50 μm and 300 μm,.

Manufacturing process according to claim 20, comprising a step of forming a central body of the film (1) which is constituted by at least one polymeric layer (6), the step of forming the central body comprising:

• An operation for preparing a second polymeric composition including an elastomeric thermoplastic material or precursors of this material, the second composition being mixed until a homogeneous and transparent solution in the liquid state is obtained,
• A coating operation of the second polymeric composition on the first layer (2, 3) in the cohesive state,
• An operation of drying and/or polymerization of the second polymeric composition in order to make it pass from the liquid state to the cohesive state, thus forming a polymeric layer (6) constituting the central body integral with the layer (2, 3) in the cohesive state on which it was coated,

the step of forming the central body is inserted between the steps of forming the first and the second layer (2, 3) comprising the biocide. Manufacturing process according to one of Claims 20 and 21, each drying operation is carried out by applying a temperature of between 70°C and 200°C for a period of less than 10 minutes.