EP4347694A1 - Masterbatch with bacteriostatic or bactericidal activity, production method thereof, and uses of same - Google Patents

Abstract

The present invention relates to a masterbatch comprising at least one thermoplastic polymer and at least one ionene polymer, as well as to the production method thereof. The present invention also relates to the use of such a masterbatch for producing an article having bacteriostatic or bactericidal properties.

Description

Title: MASTERBATCH WITH BACTERIOSTATIC OR BACTERICIDAL ACTIVITY, METHOD FOR PREPARATION AND ITS USES

DESCRIPTION

TECHNICAL AREA

The present invention belongs to the technical field of antibacterial materials and, more particularly, materials with a thermoplastic matrix comprising polymers with bacteriostatic or bactericidal activity of the ionene type.

More particularly, the present invention relates to a composition of the masterbatch type (or “masterbatch” in English) comprising a thermoplastic resin and polyionenes as well as its method of preparation. The present invention also relates to the various uses of this composition. In fact, it can be used, directly or after dilution in a thermoplastic, for the preparation of active plastic articles, capable of controlling, limiting or inhibiting the bacterial growth of undesirable flora (spoilage and pathogenic) and this, both for applications in the food industry and in the health, medical, military or environmental fields.

PRIOR ART

For economic, health and/or environmental concerns, there has been a growing demand in recent years for antibacterial surfaces or coatings which allow a lasting action of decontamination in the field of packaging of food products such as fresh food products, the environment or the medical-hospital environment.

Different strategies have been proposed in order to confer antibacterial properties on polyethylene, or more generally on polyolefins or plastic materials. A first method consists of the adsorption of small organic molecules, such as nisin [1] or ascorbic acid [2], or essential oils, such as thymol [3] or carvacrol [4], on the surfaces. This process is not ideal because the release of these molecules is inevitable when a molecule is adsorbed on a surface. Not only do these surfaces lose effectiveness over time, but the release of these molecules into the product can also lead to an alteration in freshness or taste in the case of essential oils, for example. More problematically, these molecules can also induce consumer toxicity. On the other hand, these organic molecules generally resist very little to industrial processes at high temperature such as processes for the extrusion of plastic films.

To overcome the lack of stability of organic molecules at high temperature, a second method consists of replacing them with inorganic nanoparticles. Thus, inorganic species such as silver [5], ZnO [6] or T1O2 [7] are indeed very effective from an antibacterial point of view and it is even possible to control their release by using montmorillonite supports. , clay [8] or S1O2 [9] barriers. However, the toxicity of these species is proven or suspected and the lack of hindsight on the toxicity of nanoparticles in general [10] prevents any marketing of films containing nanoparticles, particularly in the food industry.

In this field, antimicrobial polymers are particularly interesting because they generally also have a long-term activity with, in addition, a high chemical stability (reduction of residual toxicity and microbial resistance). Among these, polycations based on quaternary ammonium salts and with a modulated amphiphilic character, have been described as capable of effectively disrupting the outer and cytoplasmic membrane of cells leading to lysis and therefore cell death. It has been demonstrated that one of the key parameters for an effective antibacterial effect of the polymer is its amphiphilic character, namely the hydrophobic/charge ratio. When these polymers are used as contact-active (bacteriostatic) coatings, it has been clearly shown that (i) the presence of sufficiently long hydrophobic chains is necessary to penetrate and burst the bacterial membrane, and (ii) high levels of positive charges are required to confer antimicrobial properties, independent of the length of the hydrophobic chains [11].

In this context, polyionenes (PI) or ionenes containing quaternary ammoniums, in the main chain of the polymer or backbone, separated by hydrophobic moieties, are particularly interesting candidates [12-16]. Indeed, Strassburg et al demonstrated that polyionenes exhibit particularly effective antimicrobial properties, mainly due to the presence of alkyl groups of variable length [13]. It was also shown that these polymers exhibited low cytotoxicity [14] and the Argawal group also introduced ethoxyethyl and aliphatic segments inside the ionene structure to evaluate the influence of these segments at the level of biocidal activity and enhance the biocompatibility of these polymers [15]. More recently, a comprehensive study on the activity of ionenes has been carried out by the groups of Hedrick and Yang on clinically isolated multidrug-resistant (MDR) microorganisms [16]. This study showed that these microorganisms, although resistant to many antibiotics, were sensitive to polyionenes.

The present inventors have already proposed a method for preparing a pro-adhesive coating with bacteriostatic or bactericidal properties aimed at obtaining a bacteria trap [17,18]. This process involves a succession of adherent or grafted coatings, in a robust and/or covalent manner, from the initial substrate to the bacteriostatic or bactericidal polymers based on polyionenes.

The inventors have set themselves the goal of no longer offering a coating but a material whose production is easily industrializable and making it possible to manufacture articles on the surface of which the spread of bacteria is limited by killing them (bactericide) or by inhibiting their growth ( bacteriostatic). DISCLOSURE OF THE INVENTION

The present invention makes it possible to achieve the goal that the inventors have set themselves and therefore relates to a composition with bacteriostatic or bactericidal properties aimed at obtaining various articles which can be used as bacteria traps.

The inventors propose directly incorporating polymers with bacteriostatic or bactericidal activity of the ionene type during the preparation of plastic films by extrusion. For this, a polyionene (PI)/thermoplastic polymer such as polyethylene (PE) premix is made in the form of a masterbatch, to be used directly in one of the dies of an extrusion line which makes it possible to manufacture multilayer films useful in the field of food packaging.

The presence of PI in the multilayer films has been demonstrated via various characterization techniques and it has been shown that the films thus formed have pro-adhesive and antibacterial properties (see the experimental part below). In the field of food packaging, the films prepared from the masterbatch according to the invention, both pro-adhesive and bacteriostatic/bactericidal, make it possible to trap the undesirable flora (spoilage and pathogen) in an irreversible manner and have an impact particularly interesting both economically and environmentally. Indeed, they are particularly useful for better preservation of fresh products, a reduction in the use-by date (DLC) and a reduction in food waste in the field of packaging.

The use of polymers of the ionene type offers the advantage of having a bacteriostatic or bactericidal property which is both pro-adhesive (the bacteria are trapped), and adjustable in terms of bactericidal power. Indeed, depending on the monomers (dihalogens and diamines) used to prepare these polymers, it is possible to inhibit, in whole or in part, the strains present. In addition, in the present invention, there is no limitation as to the ionene type polymers which can be used.

Furthermore, depending on the technique used to prepare the masterbatch object of the present invention, it is possible to avoid the release of PI by creating covalent bonds between the PI and the thermoplastic polymers thanks to the addition additives and/or the use of reactive extrusion. It should be noted however that, for certain applications, the release of PI can be sought.

Beyond the application in the agro-food field, the present invention can also be applied very usefully in the health, medical, medico-hospital, military or environmental field in the broad sense, with a view to manufacturing, from said masterbatch, plastic articles such as decontamination or purification objects including rods, probes and membranes and/or containers such as a tray, bottle, case and packaging film which can advantageously serve as "bacteria traps thus reducing the bacterial load in the packaged product. The low cytotoxicity of polyionenes and their ability to limit bacterial resistance are additional advantages for this type of application.

Thus, the present invention relates to a masterbatch comprising at least one thermoplastic polymer and at least one polymer of ionene type. The concept of masterbatch comes from the plastics industry. Indeed, the masterbatch, object of the present invention is a composition with bacteriostatic or bactericidal effect obtained by extrusion of a mixture comprising at least one thermoplastic polymer and at least one polymer of ionene type and optionally one or more additives.

In other words, the present invention relates to a masterbatch obtained by extrusion, comprising at least one thermoplastic polymer and at least one polymer of the ionene type which comprises, in its main chain, a sequence of repeating units, identical or different, each unit being chosen between the unit of formula (III) and the unit of formula (IV):

-N ⁺ (R1)(R2)-AN ⁺ (R3)(R4)-B-(III)

-N ⁺ (R3)(R4)-AN ⁺ (R1)(R2)-B- (IV) in which

- RI, R2, R3 and R4, identical or different, represent an optionally substituted alkyl group or an optionally substituted aryl group;

- A is a chain chosen from the group consisting of an optionally substituted alkylene chain, an optionally alkenylene or alkynylene chain substituted, an optionally substituted arylene chain, an optionally substituted alkylarylene chain and an optionally substituted arylalkylene chain; and

- B is a chain chosen from the group consisting of an optionally substituted alkylene chain, an optionally substituted alkenylene or alkynylene chain, an optionally substituted arylene chain, an optionally substituted alkylarylene chain and an optionally substituted arylalkylene chain.

The masterbatch which is the subject of the present invention is in the form of a thermoplastic material in which and on the surface of which there are polymers of the ionene type and optionally one or more additive(s).

Thermoplastic polymers, also referred to as thermoplastic resins, are melt-processable materials. Thus, in most manufacturing processes, thermoplastics are heated, then formed into a fluid state (liquid, viscous or softened) by injection molding, extrusion or thermoforming, before being cooled whereby the finished product retains its form.

Typically, the thermoplastic polymer(s) that can be used in the context of the present invention are chosen from the group consisting of polyamides; saturated polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); polyethers; polyvinyl chloride (PVC); vinyl copolymers; polyolefins; polyurethanes; polycarbonates; styrenic polymers such as polystyrene (PS) and acrylonitrile butadiene styrene (ABS); and poly(meth)acrylates such as polymethyl methacrylate (PMMA) as well as combinations or mixtures thereof.

In a particular embodiment, the thermoplastic polymer(s) that can be used in the context of the present invention are chosen from the group consisting of polyamides; saturated polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); polyvinyl chloride (PVC); polyolefins; styrenic polymers such as polystyrene (PS) and acrylonitrile butadiene styrene (ABS); and poly(meth)acrylates such as polymethyl methacrylate (PMMA) as well as combinations or mixtures thereof. In an even more particular embodiment, the thermoplastic polymer(s) that can be used in the context of the present invention is/are one or more polyolefin(s) chosen from the group consisting of polyethylene (PE), low density polyethylene (LDPE or LDPE), linear low density polyethylene (LDPE or LLPDE), high density polyethylene (HDPE or HDPE), polypropylene (PP), polymethylpentene (PMP) and polybutene-1 (PB-1).

The total quantity of thermoplastic polymer(s) in the masterbatch which is the subject of the present invention is between 50% and 98% by mass, in particular between 70% and 97% and, in particular, between 80% and 96 % by mass relative to the mass of said masterbatch.

By "polymer of the ionene type" is meant, in the context of the present invention, a cationic polymer of which all or part of the positive charges are provided by quaternary ammoniums present in the main chain of the polymer, said positive charges being separated by hydrophobic segments. In what follows and what precedes, the expressions and terms “polymer of the ionene type”, “ionene”, “polyionene” and “PI” are equivalent and can be used interchangeably.

Any polymer of the ionene type capable of being obtained by reaction of a diamine and a dihalogen can be used in the context of the present invention.

Advantageously, the diamine used to prepare the polymer of ionene type which can be used in the process according to the invention is of formula (I):

(R1)(R2)N-A-N(R3)(R4) (I) in which

- RI, R2, R3 and R4, identical or different, represent a hydrogen atom, an optionally substituted alkyl group or an optionally substituted aryl group and, in particular, an optionally substituted alkyl group or an optionally substituted aryl group; and

- A is a chain chosen from the group consisting of an optionally substituted alkylene chain, an optionally substituted alkenylene or alkynylene chain, an optionally substituted arylene chain, an optionally substituted alkylarylene chain and an optionally substituted arylalkylene chain. By "alkyl group" is meant an alkyl group, linear, branched or cyclic, comprising from 1 to 20 carbon atoms, in particular from 1 to 15 carbon atoms and, in particular, from 1 to 10 carbon atoms, said group alkyl possibly comprising at least one heteroatom and/or at least one carbon-carbon double or triple bond.

By "heteroatom" is meant, in the context of the present invention, an atom chosen from the group consisting of nitrogen, oxygen, phosphorus, sulfur, silicon, fluorine, chlorine and bromine.

By "substituted alkyl group" is meant, in the context of the present invention, an alkyl group as defined above substituted by one or more groups, identical or different, chosen from the group consisting of a halogen; an amine; a diamine; a carboxyl; a carboxylate; an aldehyde; an ester; an ether; a ketone; a hydroxyl; optionally substituted alkyl; an amide; a sulphonyl; a sulphoxide; a sulphonic acid; a sulphonate; a nitrile; a nitro; an acyl; an epoxy; a phosphonate; an isocyanate; a thiol; a glycidoxy and an acryloxy.

By "halogen" is meant, in the context of the present invention, an atom chosen from the group consisting of an iodine, a fluorine, a chlorine and a bromine.

As specific examples of alkyl groups that can be used for R1 to R4, mention may be made of methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl, heptyl, octyl and nonyl.

By "aryl group" is meant, in the context of the present invention, any group comprising an aromatic ring or several aromatic rings, identical or different, linked or connected by a single bond or by a hydrocarbon chain, an aromatic ring having 3 to 20 carbon atoms, in particular from 4 to 14 carbon atoms and, in particular, from 5 to 8 carbon atoms and possibly comprising a heteroatom. As an aryl group that can be used in the invention, mention may be made of a phenyl group.

By "substituted aryl group" is meant, in the context of the present invention, an aryl group as defined above, substituted by a group or several groups, identical or different, chosen from the group consisting of a halogen; an amine; a diamine; a carboxyl; a carboxylate; an aldehyde; an ester; an ether; a ketone; a hydroxyl; optionally substituted alkyl; an amide; a sulphonyl; a sulphoxide; a sulphonic acid; a sulphonate; a nitrile; a nitro; an acyl; an epoxy; a phosphonate; an isocyanate; a thiol; a glycidoxy and an acryloxy.

As particular examples of aryl groups which can be used for R1 to R4, mention may be made of the phenyl, biphenyl, naphthyl, anthracenyl, cyclopentadienyl, pyrenyl or alternatively naphthyl groups.

By "alkylene chain" is meant, in the context of the present invention, an alkylene chain, linear, branched or cyclic, comprising from 1 to 30 carbon atoms, in particular from 2 to 20 carbon atoms and, in particular, from 3 to 15 carbon atoms, said alkylene chain possibly comprising at least one heteroatom.

By "alkenylene or alkynylene chain" is meant, in the context of the present invention, an alkenylene or alkynylene chain, linear, branched or cyclic, comprising from 2 to 30 carbon atoms, in particular from 3 to 20 carbon atoms and, in particular, from 5 to 15 carbon atoms, said alkenylene or alkynylene chain possibly comprising at least one heteroatom.

By "arylene chain" is meant, in the context of the present invention, any chain comprising an aromatic ring or several aromatic rings, identical or different, linked or connected by a single bond or by a hydrocarbon chain, an aromatic ring having 3 to 20 carbon atoms, in particular from 4 to 14 carbon atoms and, in particular, from 5 to 8 carbon atoms and possibly comprising a heteroatom.

By “alkylarylene chain” is meant, in the context of the present invention, any chain derived from an arylene chain as defined above, one hydrogen atom of which is replaced by an alkyl group as defined above.

By “arylalkylene chain” is meant, in the context of the present invention, any chain derived from an alkylene chain as defined above, one hydrogen atom of which is replaced by an aryl group as defined above.

By “substituted alkylene chain”, “substituted alkenylene or alkynylene chain”, “substituted arylene chain”, “substituted alkylarylene chain” and “arylalkylene chain substituted", means, in the context of the present invention, an alkylene chain, an alkenylene or alkynylene chain, an arylene chain, an alkylarylene chain and an arylalkylene chain as defined above substituted by a group or several groups, identical or different, selected from the group consisting of carboxyl; a carboxylate; an aldehyde; an ester; an ether; a ketone; a hydroxyl; optionally substituted alkyl; an amide; a sulphonyl; a sulphoxide; a sulphonic acid; a sulphonate; a nitrile; a nitro; an acyl; an epoxy; a phosphonate; an isocyanate; a thiol; a glycidoxy and an acryloxy.

As examples of alkylene chains that can be used in the invention, mention may be made of a methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, decylene, undecylene, dodecylene chain and a chain of formula -(CH2) _n -0-(CH2)m- or -(CH2) _n -S-(CH2)m- with n and m, identical or different, representing 0 or an integer between 1 and 20 and with n+m greater than or equal to 1.

As more specific examples of alkylene chains that can be used in the invention, mention may be made of a propylene, butylene, pentylene, hexylene, heptylene, octylene, decylene, undecylene, dodecylene chain and a chain of formula -(CH2) _n -0 -(CH2) _m - or -(CH2) _n - S-(CH2) _m - with n and m, identical or different, representing 0 or an integer between 1 and 20 and with n+m greater than or equal to 1 .

As examples of arylene chains that can be used in the invention, mention may be made of a phenylene or biphenylene chain.

In a particular embodiment, the radicals R1, R2, R3 and R4 are identical. In a more particular embodiment, the radicals R1, R2, R3 and R4 are identical alkyl groups. In an even more particular embodiment, the radicals R1, R2, R3 and R4 are identical and represent a methyl or an ethyl.

Advantageously, the dihalogen used to prepare the polymer of ionene type which can be used in the process according to the invention is of formula (II):

(R5)-B-(R6) (II) in which

- R5 and R6, identical or different, represent a halogen; and - B is a chain chosen from the group consisting of an optionally substituted alkylene chain, an optionally substituted alkenylene or alkynylene chain, an optionally substituted arylene chain, an optionally substituted alkylarylene chain and an optionally substituted arylalkylene chain.

In a particular embodiment, the radicals R5 and R6 are identical. In a more particular form of implementation, the radicals R5 and R6 are identical and represent a bromine atom, a chlorine atom or an iodine atom. In an even more particular form of implementation, the radicals R5 and R6 are identical and represent a bromine atom.

Thus, the ionene-type polymer that can be used in the context of the present invention comprises, in its main chain, a sequence of repeating units, which are identical or different, each unit being chosen between the unit of formula (III) and the unit of formula ( IV):

-N ⁺ (R1)(R2)-AN ⁺ (R3)(R4)-B-(III)

-N ⁺ (R3)(R4)-AN ⁺ (R1)(R2)-B- (IV) in which R1, R2, R3, R4, A and B are as previously defined.

In a particular embodiment, the ionene-type polymer used in the present invention comprises, in its main chain, a sequence of repeating units, which are identical or different, each unit being of formula (III) as defined above in which :

- A represents an alkylene comprising from 3 to 12 carbon atoms and in particular 6 atoms,

- B represents an alkylene comprising from 3 to 12 carbon atoms and in particular 6 carbon atoms, and

- the radicals RI, R2, R3 and R4, which are identical or different, represent a methyl or an ethyl.

Advantageously, in this particular embodiment, the radicals R1, R2, R3 and R4 are identical. Typically, the ionene-type polymer is prepared via a polyaddition also known under the expression “Menschutkin reaction” involving at least one diamine of formula (I) as defined previously and at least one dihalide of formula (II) such as previously defined. The R1, R2, R3 and R4 radicals carried by the diamine(s) and the R5 and R6 radicals carried by the dihalide(s) are the reactive functions during this polyaddition reaction.

The latter is carried out at a temperature above ambient temperature. “Room temperature” means a temperature of 23°C ± 5°C. Advantageously, the temperature during the polyaddition is above 30°C. Typically, the temperature during the polyaddition is between 40°C and 80°C, in particular, between 55°C and 75°C and, more particularly, is of the order of 65°C (i.e. 65°C ± 5°C). Advantageously, during the polyaddition step, the diamine(s) and the dihalide(s) are in solution in a polar, protic or aprotic solvent. This solvent is in particular /V,/V-dimethylformamide (DMF) or a hydroxylated solvent, in particular methanol, ethanol or a mixture thereof, and more particularly methanol.

By routine work, the person skilled in the art will be able to determine, without inventive effort, the quantity of diamine(s) and halide(s) to be used according in particular to their solubility in the solvent as well as the duration of polyaddition. By way of example, this duration may be between 4 h and 30 h, in particular between 5 h and 24 h and, in particular, between 6 h and 15 h. This polyaddition is typically carried out with stirring and, advantageously, under an inert atmosphere. It is stopped by cooling the reaction medium.

The total quantity of polymer(s) of ionene type in the masterbatch which is the subject of the present invention is between 0.5% and 50% by mass, in particular between 1% and 30% and, in particular, between 2% and 10% by mass relative to the mass of said masterbatch. As specific examples of masterbatch object of the present invention, mention may be made of a masterbatch comprising 3%, 5%, 10% by mass of polymer(s) of ionene type relative to the total mass of said mixture. -master. In addition to the thermoplastic polymer(s) and the polymer(s) of ionene type, the masterbatch according to the present invention may comprise at least one additive.

Any additive that can be used in the field of plastics processing can be used in the context of the present invention. A person skilled in the art will be able to determine the additive(s) to be added on the basis of the properties sought for the masterbatch or for the article prepared from the latter.

Typically, the additive(s) present in the masterbatch according to the present invention are chosen from the group consisting of plasticizers, dispersants and/or compatibilizers; agents producing radical species; UV absorbers such as benzotriazoles and hydroxybenzophenones; photo-oxidation inhibitors such as hindered amine light stabilizers; moisture absorbers such as calcium hydroxide; antioxidants; organic pigments such as anthraquinones, phthalocyanines, polycyclic pigments and azo pigments; inorganic (or mineral) pigments such as titanium dioxide, cobalt-based pigments, titanates, iron oxides, manganese pigments, chromium oxides, carbon black and carbon black; heat stabilizers; flame retardants such as aluminum trihydrate, magnesium hydroxide, inert silicon fillers, phosphoric acids and chlorinated hydrocarbons; organic fillers such as wood flour and synthetic or natural fibers; mineral fillers such as talc, graphite, mica, silica and chalk; lubricating (or gliding) agents such as calcium stearate, polyethylene waxes and silicones and mixtures thereof.

In a particular embodiment, said additive is a plasticizing, dispersing and/or compatibilizing agent. As plasticizer(s), dispersant(s) and/or compatibilizer(s) usable in the context of the present invention, mention may be made of copolymers of ethylene and vinyl acetate such as than the product marketed under the brand Evatane 2825 ^® by the company Arkema or the product marketed under the brand Viscowax 334 ^® (Cire EVA) by the company Innospec, waxes such as waxes of polyethylene, ethylene copolymer waxes and oxidized polyethylene waxes marketed in the ^Luwax® range by the company BTC; the product marketed under the trademark ^BYK® P4102 by the company BYK; phthalates; epoxies; aliphatic dicarboxylic acid esters; polyethylenes or polypropylenes grafted with maleic anhydride (GMA) groups, such as the product marketed under the trademark Lushan LR-2D by the company Guanzhou Lushan New Materials; potassium laurate; polyesters; phosphates and mixtures thereof.

In another particular embodiment, said additive is an agent producing radical species. Any agent producing radical species usually used in the context of reactive extrusion can be used in the context of the present invention. Typically, the agent producing radical species used in the context of the present invention is chosen from the group consisting of hydro peroxides, organic peroxides, amines and azo compounds of formula R7-N=N-R8 with the radicals R7 and R8, identical or different, representing an optionally substituted alkyl group as previously defined or an optionally substituted aryl group as previously defined. In particular, this agent is chosen from the group consisting of hydro peroxides, organic peroxides and mixtures thereof. Mention may be made, as such agents which can be used in the invention, of 1,3-1,4-bis(tert-butylperoxyisopropyl)benzene sold under the brand name Luperox ^® F40, benzoyl peroxide sold under the brand name Luperox ^® A75, dicumyl-peroxide sold under the Luperox ^® DCP brand, 2,5-dimethyl-2,5-di(tert-butyl-peroxy)hexane sold under the Luperox ^® 101 brand, tert-butylcumyl-peroxide sold under the Luperox ^® 801, n-butyl-4,4-di(tert-butylperoxy)valerate sold under the Luperox ^® 230 brand, l,l-di(t-butylperoxy)-3,3,5-trimethylcyclohexane sold under the brand Luperox ^® 231 and G hydro peroxide of di-isopropylbenzene marketed under the brand Luperox ^® DH, the Luperox ^® range being sold by the company Arkema.

Advantageously, the additive(s) used in the context of the present invention is/are at least one plasticizer, dispersant and/or compatibilizer and/or at least one agent producing radical species. When the masterbatch which is the subject of the present invention comprises at least one additional additive, the quantity of this or these additive(s) is between 0.05% and 30% by weight and in particular between 0.1% and 20% by weight. mass relative to the mass of said masterbatch.

In a particular embodiment, when said at least one additive comprises at least one plasticizer, the plasticizer(s), dispersant(s) and/or compatibilizer(s) is/are present in one quantity comprised between 0.1% and 20% by mass relative to the mass of said masterbatch.

In another particular embodiment, when said at least one additive comprises at least one agent producing radical species, the agent(s) producing radical species is/are present in an amount of between 0.05% and 10% by mass relative to the mass of said masterbatch.

The present invention also relates to a method for preparing a masterbatch as defined above. This process comprises the extrusion of a mixture comprising at least one thermoplastic polymer, in particular as defined above, at least one polymer of the ionene type, in particular as defined above, and optionally at least one additive, in particular as defined above, at a temperature lower than or equal to 250°C, whereby a masterbatch comprising at least one thermoplastic polymer, at least one polymer of ionene type and optionally at least one additive is obtained.

During the process according to the present invention, the thermoplastic polymer(s) are typically in the form of granules. Furthermore, the total quantity of thermoplastic polymer(s) in the mixture used in the process which is the subject of the present invention is between 50% and 98% by mass, in particular between 70% and 97% and, in particular, between 80% and 96% by mass relative to the mass of said mixture.

During the process according to the present invention, the polymer(s) of ionene type are typically in the form of powders, optionally micronized and/or sieved so as to have particles whose size is less than 50 μm. The total amount of ionene-type polymer(s) in the mixture used in the process object of the present invention is between 0.5% and 50% by mass, in particular between 1% and 30% and, in particular, between 2% and 10% by mass relative to the mass of said mixture.

During the process according to the present invention, the optional additive(s) are typically in liquid form or in powder form. The amount of this or these additive(s) in the mixture used in the process that is the subject of the present invention is between 0.05% and 30% by mass and in particular between 0.1% and 20% by mass relative to the mass of said mixture.

In a particular embodiment, when said at least one additive comprises at least one plasticizer, dispersant and/or compatibilizer, the plasticizer(s), dispersant(s) and/or compatibilizer(s) is/are present(s), in the mixture used in the process which is the subject of the present invention, in an amount of between 0.1% and 20% by mass relative to the mass of said mixture.

In another particular embodiment, when said at least one additive comprises at least one agent producing radical species, the agent(s) producing radical species is/are present, in the mixture used in the process object of the present invention, in an amount of between 0.05% and 10% by mass relative to the mass of said masterbatch.

The extrusion step of the process according to the present invention typically implemented in an extruder is carried out at a temperature of between 100° C. and 250° C., in particular between 130° C. and 220° C. and, in particular, of around 150°C (i.e. 150°C ± 10°C) or around 180°C (i.e. 180°C ± 10°C). A person skilled in the art will know how to adapt the temperature during extrusion according to the thermoplastic polymer(s) used.

The mixture between the various constituents which are the thermoplastic polymer(s), the ionene-type polymer(s) and the optional additive(s) can be carried out prior to its introduction into the the extruder and in particular in a mixer or kneader or during its introduction into the extruder. As a variant, the various constituents of this mixture can be introduced, into the extruder, one after the other or in groups. Thus, when the mixture comprises an additive such as a plasticizing, dispersing and/or compatibilizing agent and/or an agent producing radical species, the introduction of this agent can be carried out via an injection finger after the mixing of the other constituents, or during a second pass, depending on the melting of the mixture, so as to control the action of the agent, in particular of the agent producing radical species, by acting on the temperature or the residence time in the extruder. It is also possible to envisage introducing the agent producing radical species upstream of the mixture, either before the addition of the ionene-type polymer and/or the other additive(s) such as a or plasticizer(s), dispersant(s) and/or compatibilizer(s). As a further variant, this additive such as a plasticizing, dispersing and/or compatibilizing agent and/or an agent producing radical species can be introduced, into the extruder, downstream of the zone for introducing the mixture comprising at least one thermoplastic polymer, at least one polymer of ionene type and optionally at least one other additive. Typically, at the level where the plasticizer, dispersant and/or compatibilizer and/or the agent producing radical species is introduced, the thermoplastic polymer(s), the ionene-type polymer(s) and optionally the additive(s) are in the form of a viscous or softened, relatively homogeneous phase.

The fact of using, in the mixture implemented in the process according to the invention, an agent producing radical species facilitates the anchoring of the ionene-type polymers in the thermoplastic matrix of the masterbatch, by creating covalent bonds between polymers of ionene type and thermoplastic polymers forming this matrix. In this case, the extrusion implemented in the preparation process is a reactive extrusion. The latter requires the use, as an additive in the mixture, of at least one agent producing radical species.

The masterbatch thus prepared comes in the form of rods which can then be cut into granules and used directly in implementation processes. The present invention therefore relates to the use of a masterbatch as defined above to prepare an article having bacteriostatic or bactericidal properties.

Thus, the present invention relates to an article having bacteriostatic or bactericidal properties prepared from a masterbatch as defined above.

As previously mentioned, the present invention applies to any article with a thermoplastic matrix that can be used not only in the packaging and preservation of products but also as a device for protection, decontamination and/or purification in the medical-hospital field or of the environment. By “article with a thermoplastic matrix”, is meant a manufactured article whose essential constituent is a thermoplastic resin. This article can therefore be chosen from the group consisting of a film such as, for example, a packaging film, a box, a tray, a bottle, a case such as a box for lenses, a case, a lid, a bag, dialysis equipment, a rod, a probe, a membrane and a filter.

The present invention therefore relates to a method for preparing an article having bacteriostatic or bactericidal properties from a masterbatch as defined above. This process comprises the transformation of the masterbatch as previously defined, optionally mixed with a thermoplastic resin into an article.

The masterbatch can be used, directly, after its preparation. Alternatively, it can be diluted in a thermoplastic resin. In this variant, the method for preparing an article having bacteriostatic or bactericidal properties from a masterbatch as previously defined, comprises mixing the masterbatch as previously defined with a thermoplastic resin, whereby a thermoplastic composition is obtained and then the transformation of this thermoplastic composition into an article.

During the mixing step of the process for preparing an article according to the present invention, the amount of masterbatch is between 5% and 40% by mass and in particular between 8% and 35% by mass relative to the total mass of the thermoplastic composition. Any thermoplastic resin, in particular as defined above, can be used in the context of the method according to the present invention. This thermoplastic resin may be identical to or different from the thermoplastic polymer(s) included in the masterbatch. A person skilled in the art will know how to choose, without inventive effort, the most suitable thermoplastic resin depending on the article to be prepared and the thermoplastic polymer(s) already present in the masterbatch.

The forming step in the preparation process according to the present invention can be any shaping technique conventionally used in the field of plastics processing. By way of illustrative and non-limiting examples, mention may be made of injection molding, extrusion molding, coextrusion molding, thermoforming, compression molding, blow molding, stretch blow molding and 3D printing. Thus, the article according to the present invention is in the form of a molded, extruded, injected article, in films, in sheets, in fibers, in composite materials such as coextruded objects and in multilayer films.

The experimental part below illustrates the preparation by coextrusion of a multilayer film, one of the outer layers of which is prepared from a masterbatch according to the present invention.

The article according to the invention or prepared according to a preparation process according to the invention has, in its thickness and on the surface, polymers of the ionene type. Indeed, these charged polymers have the ability to migrate, in neutral thermoplastics, to the surface of the article thus prepared. The ionene-type polymers present on the surface of the article make it possible to confer on the latter bacteriostatic or bactericidal properties and to make it a trap for bacteria.

Even if some of the ionene-type polymers can be released from the surface of the articles, it is possible to minimize this release, in particular by using masterbatches containing additives and/or obtained via reactive extrusion.

Alternatively, this release may have advantages and be desirable. For example, when the article according to the invention or prepared according to a method of preparation according to the invention is an article capable of containing a liquid such as a cleaning solution, the release of the ionene-type polymers in this liquid has a disinfectant role.

Other characteristics and advantages of the present invention will become apparent to those skilled in the art on reading the examples below given by way of illustration and not limitation, with reference to the appended figures.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 presents epifluorescence microscopy images of the Staphylococcus aureus strain on the PE films obtained from the various masterbatches.

Figure 2 shows the count in deionized water of the total flora and viable cultivable bacteria adherent to S. aureus on the control PE MM films (no. 2), 10% (no. 4) and 30% (no. 6). ).

Figure 3 shows the count of the adhesion supernatants of 5. aureus in deionized water of the control PE MM films (n°2), 10% (n°-4) and 30% (n°6) (SM = Mother Suspension contaminating).

Figure 4 presents the results of cytotoxicity on cell layers of mouse fibroblasts (L929) in culture for the control PE MM (n°2), 10% (n°4) and 30% (n°6), the control corresponds to the same culture medium but without PE MM.

FIG. 5 presents the results of cytotoxicity on reconstructed human epidermis in the presence of PBS for the control PE MM (no. 2), 10% (no. 4) and 30% (no. 6). The negative control corresponds to PBS alone and the positive control to PBS with a latex glove extract.

Figure 6 presents the water contact angle measurements taken on the macro and pico-goniometer.

Figure 7 presents the evolution of the zeta potential as a function of the pH for the films of PE MM. Figure 8A shows the release measurements after washing, for a 3% PE-PI 6-6 mixture with or without 1% EVA wax (plasticizer, dispersant and/or compatibilizer) and/or 0.25% peroxide.

Figure 8B shows the release measurements after washing, for a PE-PI 6-6 mixture at 3% with or without 1% of Lushan LR-2D (plasticizer, dispersant and/or compatibilizer) and/or 0.25% of peroxide.

Figure 8C shows the release measurements after washing, for a PE-PI 6-6 mixture at 3% with or without 1% potassium laurate (plasticizer, dispersant and/or compatibilizer) and/or 0.25% peroxide .

DETAILED DISCUSSION OF PARTICULAR EMBODIMENTS

I. PE/PI masterbatch (MM) manufacturing process.

1.1. Synthesis of polyionene PI 6-6.

The following reagents were ordered from Sigma-Aldrich. Solvents were ordered from Carlo Erba reagent. All reagents were used upon receipt, without further purification.

All the compounds are introduced into a 250 mL three-necked flask under an inert atmosphere, topped with a condenser, in order: N,N,N',N'-tetramethyl-1,6-diaminohexane (23.0 mL, 0.1076 mol), 60 mL of methanol, 1,6-dibromohexane (16.6 mL, 0.1095 mol) and 60 mL of methanol. The reaction mixture, homogeneous and clear, is heated to 65° C. between 6 a.m. and 3 p.m. with stirring. The reaction is stopped by cooling the reaction medium. The mixture obtained is precipitated in acetone. The precipitate obtained is filtered off and dried.

A white solid of mass m=52.98 g is obtained. ¹ H NMR (D2O, d in ppm): 1.39 (s, 8H); 1.74 (s, 8H); 2.83 (s, 0.27H, amine end); 3.01 (s, 12H); 3.23-3.30 (m, 8H); 3.46-3.49 (t, 0.38H, brominated end).

The polyionene thus obtained is PI 6-6 of formula: 1.2. Manufacture of MM based on PI 6-6 and LDPE.

About 150 g of PI 6-6 were synthesized by following the synthesis protocol explained in point 1.1 above. The PI 6-6 obtained has an average molar mass M _w = 19,000 g. mol ¹ and a polydispersity index of 2.3 (determined by size exclusion chromatography). The masterbatch (MM) was obtained from a mixture of approximately 950 g of low density polyethylene (PEBD, LDPE 410 E, DOW) with 50 g of PI 6-6, i.e. a MM of 5% in mass of PI 6-6. A 3% by weight MM of PI 6-6 was also prepared from approximately 970 g of LDPE and 30 g of PI 6-6.

The realization of the MM requiring an extrusion step, the thermal resistance of different PI was evaluated by thermogravimetric analyzes (ATG) under dinitrogen and dioxygen. These analyzes make it possible to affirm that the PIs can be extruded up to a temperature of approximately 250° C., without risk of degradation of the latter. The results are collated in Table 1 below.

Table 1: Thermogravimetric analyzes of PIs under 0 _? and N _?

T10 represents the degradation temperature of 10% of the initial mass of the sample, T90, the degradation temperature of 90% of the initial mass and Tf, finally the degradation temperature.

To make MM, finely ground PI powder is placed in a plastic bag. LDPE granules are added thereto and a pressurized air jet is injected into the plastic bag to mix the powder with the granules. The resulting mixture is then introduced into a mixer (or “compounder”) before being extruded at 150° C. so as to obtain rods of MM PE-PI 6-6. These rods are then cut to produce MM PE-PI 6-6 granules. About 900 g of MM PE-PI 6-6 were thus created.

More complex mixtures have also been developed with the addition of plasticizers, dispersants and/or compatibilizers (between 0.1% and 20%) to improve the mixing properties between the two compounds (PE and PI) i.e. to improve compatibility PI in the PE matrix, and therefore ultimately improve its dispersion in the film (more homogeneous distribution of PI). The plasticizers, dispersants and/or compatibilizers used are the following: Evatane 2528, Luwax A, ViscoWax 334(r)/EVA Wax, BYK P4102, Potassium Laurate, Lushan LR-2D, etc.

Masterbatches have also been developed using reactive extrusion in the presence of peroxides (between 0.05% and 10%) in order to anchor the PI more robustly in the PE (formation of a covalent bond inter-chains). The peroxides used are the Luperox ^® range (F40P, A75, 231, 230, etc.) and all other formulations that can allow a radical reaction between the polymers present. Reactive extrusion in the presence of peroxide, with or without plasticizers, dispersants and/or compatibilizers, consists of (1) introducing the mixture comprising the PE and PI and optionally a plasticizer, dispersant and/or compatibilizer into the mixer, (2 ) dispersing the PI in the PE whereby a good homogeneity between the phases is obtained, (3) adding peroxide whereby the PI is grafted onto the PE and (4) obtaining a stable homogeneous mixture. Note that the plasticizer, dispersant and/or compatibilizer can also be added during and/or after the addition of the peroxide.

II. Production of the PE film with the masterbatch PE-PI 6-6.

PE films 100 μm thick are implemented by extrusion at 210° C. (250 or 230 bars) by incorporating the MM PE-PI 6-6 granules into the LDPE granules which constitute the matrix. The different elements are coextruded on the pilot line with 9 Tenter-type extruders. The LDPE granules and the MM PE-PI 6-6 granules are introduced via dies, in different proportions, by controlling the flow rate and the masses introduced (filtration 940 μm). They are then melted and mixed as they pass through the screw extruder. A flat die at the exit of the extruder makes it possible to obtain multilayer films.

The target film thickness is 100 μm with a layer ratio of 90/10 (MM PE-PI layer 6-6). The layer containing the MM PE-PI 6-6 is on the outer part of the film (then inside the roll). The sheath (film of MM PE-PI 6-6), obtained at the exit of the extruder, is cooled by sliding on a mandrel, then, by immersion in a bath of cold water, in order to be in a state amorphous.

The film is then stretched (long stretch ratio of 5 or 4.5) using heated winders moving at different speeds (total flow 25 kg/h), before finally being wound up (150 m rolled up). PE films with 10% and 30% by mass of MM in the upper layer were obtained. Since the MM granules contain 5% by mass of PI 6-6, then the final films have respectively 0.5% and 1.5% by mass of PI 6-6.

Film No. 2 constitutes the control of the PE matrix without MM. Films No. 4 PE MM 10% and No. 6 PE MM 30% are the films with respectively 0.5% m/m and 1.5% m/m of PI 6-6 in the extruded films.

By choosing low density PE granules (LDPE) to constitute the main matrix of the film, the migration of surface elements is favored. This migration is also facilitated by the fact that the polyionene (PI 6-6) is charged and hydrophilic. Thus, although the PI is added in the film matrix, it should migrate to the surface and produce an antibacterial effect on contact.

III. Biological characterizations of PE MM films.

PE MM films have been characterized by adhesion assays in microbiology and cytotoxicity assays in mammalian cells.

The adhesion tests were supplemented by a count of the supernatants in order to evaluate the release of these surfaces. Indeed, there are no covalent bonds between the PIs and the PE matrix in the example given, ie without plasticizer, dispersant and/or compatibilizer, nor peroxide. Thus, the biological studies were carried out on PE MM films n°2, n°4 and n°6.

III.1. Bio-adhesion tests.

Bio-adhesion tests are tests which make it possible to highlight the impact of the presence of PIs on the adhesion of bacteria (pro-adhesive effect) and to determine the antibacterial effect of the modified materials. On the one hand, the total quantity of bacteria which has adhered to the surface, called total flora (TF), is evaluated by means of microscopic observation and counting of the bacteria on the epifluorescence images (FIG. 1). On the other hand, the quantity of living bacteria capable of multiplying after exposure to the modified surfaces, called viable adherent cultivable bacteria (VC), is evaluated by picking them up and counting them on agar culture medium.

The adhesion tests are carried out with Staphylococcus aureus (S. aureus) in distilled water for 3 hours at 37° C. with a bacterial suspension at approximately 10 ⁶ CFU.mL ¹ (CFU: Colony Forming Unit). The results presented in Figure 2 are normalized for a solution at 10 ⁶ CFU.mL ¹ precisely, and are the average of five different tests on the PE MM control and PE MM 10% films (n = 5), and of three tests different on the PE MM 30% film (n = 3). The effectiveness of the unhooking is confirmed by the majority observation of black fields on the materials after the ultrasonic unhooking.

Two significant results can be underlined on these tests. The total flora is much greater on the PE MM 10% and 30% (those with PI 6-6) than on the control PE MM. The difference between the quantity of adherent cultivable viable bacteria relative to the total flora is greater, and significantly, on the 10% and 30% PE MM films than on the control PE MM film. Indeed, the difference is 2.0; 3.8 and 5.9 log bacteria. cm ² for the control PE MM, 10% and 30% respectively.

These two observations therefore suggest that the incorporation of PI into the PE matrix confers both a pro-adhesive and antibacterial effect on the films. It should be noted that the difference between the total flora and the count of viable cultivable flora on the control is significant because of the heterogeneity of adhesion and the low number of adherent bacteria, which makes correct counting difficult. the amount of bacteria (total flora and cultivable viable flora). However, the antibacterial effect is so important in the case of PE MM that their effectiveness compared to the control is undeniable. The efficiency percentages are 99.98% and 99.9998% on PE MM 10% and 30% respectively.

In the case of the PE MM 30% film, this is a strong bactericidal effect since almost no living bacteria are found in the count of viable cultivable flora after exposure to this film. It must be verified that this important effect is only obtained by contact of the bacteria with the film or if it is not also due to a possible release of the PIs into the bacterial suspension which immerses the material.

Bioadhesion tests were also carried out on the PE MM 10% film with 10 different bacterial species (wild isolates from meat products).

The pro-adhesive effect is strain-dependent and the trapping capacity of PE MM 10% is maximal for pathogenic and spoilage bacteria (Table 2). The incorporation of PIs into PE films conferred on these surfaces a property of targeted bacteria trap. This is a very interesting property in the context of the production of food packaging in order to limit the proliferation of pathogenic flora and alterations on food while preserving the positive flora useful for example for good maturation of meat.

Table 2: Summary of the pro-adhesive effect of PE MM 10% on 10 wild-type bacterial strains

To demonstrate the presence of release (i.e. the presence of free PI released from the surface into the bacterial suspension), the counts of the contaminating suspensions (“supernatants”) used for the adhesion tests were carried out after 3 hours of adhesion. The aim was to verify whether the bacteria were inhibited by the PE MM film only in contact with the surface, or also in the suspension immersing the material. Counts of culturable viable bacteria in adhesion supernatants are shown in Figure 3.

A significant decrease in the amount of viable bacteria cultivable in the supernatant compared to the contaminating stock suspension (SM) is observed in the case of the PE MM 30% film. A slight decrease is also perceptible in the case of PE MM 10% but this is not significant (Student, p-value > 0.05). A release is therefore proven in the case of the film with the highest PI concentration. These tests were supplemented with a cytotoxicity study in order to assess the potential toxicity of the materials and the release.

III.2. Cytotoxicity tests.

To characterize the cytotoxicity of the films, a standardized test, called the MTT test, is carried out, which makes it possible to quantify the cell viability by optical density measurements. The test is carried out according to standard NF EN ISO 10993-5 which concerns the methods for evaluating the in vitro cytotoxicity of medical devices.

The cytotoxicity tests were carried out, on the one hand, on cell layers of mouse fibroblasts (L929) after 48h exposure to PE MM films and, on the other hand, on reconstructed human skin epidermis (Skin+) , after 24 h exposure to extruded films. The tests were repeated on three separate materials for each of the tests (n=3).

As the PE MM films float above the cell layers in the wells during the tests on the L929s, it is therefore possible to evaluate the release with these tests (Figure 4).

The tests do not indicate any cytotoxicity of the control PE MM and PE MM 10% since the cell viability is above 70%. In the case of PE MM 30%, the average is also above 70%, but it should be noted that the standard deviation is greater on this test and that the cytotoxicity threshold is included in the standard deviation. type of measurements. A Student test on the data showed that the difference is not significant between the control and the control PE MM film but that it is between the control and the 10% and 30% PE MM films (p-value=0.04 and p-value=0.006 respectively).

As during the evaluation of the supernatants, this test also attests to a release proportional to the concentration of PI in the film, and this does not generate cytotoxicity or only potentially in the case of the highest concentrations of PI.

For tests on reconstructed human epidermis, the PE MM films are in direct contact with the epidermis (Figure 5).

The assays do not indicate cytotoxicity of the MM PEs because the cell viabilities are above 70%. In addition, the Student tests also show that there is no significant difference between the control PE MM and the PE MM 10% and 30% (p-value > 0.05 in both cases). The absence of cytotoxicity of PE MM 30% on human epidermis compared to L929 cells can be explained by the greater fragility of L929 cells. L929s are monolayered cell mats whereas reconstructed human epidermis are multilayered systems (at least 5). This makes reconstructed human epidermis less susceptible to toxicity than L929 cells.

In view of the microbiology and cytotoxicity results, the presence of a release for high loadings of PI (PE MM 30%) is undeniable. However, the PE MM 10% did not prove to be cytotoxic under the conditions of the two tests and it has relatively effective antibacterial and pro-adhesive properties compared with the control PE MM. For this type of extruded material, depending on the application envisaged, in particular if the release is not desired, the concentration of MM in the outer layer of the film should be limited to 10% (ie 0.5% in PI). One possibility considered for limiting the release of the PIs is to use a reactive extrusion process in the presence of peroxides, to cause the PI to react with the PE of the matrix (formation of covalent bonds). IV. Physico-chemical characterizations of PE MM films.

IV.1. Contact angle measurements.

The contact angle measurements on all the films (PE MM n°2, n°4 and n°6) were carried out with drops of water D.l. microscopic (2 pL, macro-goniometer) or with smaller quantities (pico-goniometer). The pico-goniometer measurements are more precise and also make it possible to evaluate the homogeneity of the films.

In Figure 6, it appears that the contact angle values of the pico-goniometer are lower than those obtained from the microdroplets. The values obtained nevertheless follow the same trend, with lower contact angle values in the presence of PIs, compared to the control PE MM, which clearly confirms their presence on the surface.

IV.2. Zeta potential measurements.

Zeta potentials were measured on the 10% and 30% PE MM films (PE MM #4 and #6), as well as the control PE MM film (PE MM #2). Measurements at pH 4 and 5.5 are shown in Figure 7. At both pH values, the 10% and 30% MM PEs have higher zeta potentials than the control MM PE. This testifies to a greater quantity of positive charges on the films with MM PI 6-6. The appearance of positive charges on the surface of the PE MM 10% and 30% confirms the successful migration of the PIs from the PE matrix to the surface of the film.

IV.3. Study of the release of PIs.

Release studies have been carried out on different types of PE-PI mixtures with or without plasticizers, dispersants and/or compatibilizers, and in the presence or absence of peroxides (Luperox ^® F40P, 0.25%)

The results presented in FIGS. 8A, 8B and 8C show that the PE-PI-plasticizer, dispersant and/or compatibilizer-peroxide combination is rather advantageous for reducing the quantity of PI released. However, for Lushan LR-2D (maleic anhydride graft polymers) (Figure 8B) and potassium laurate (Figure 8C), it would appear that the plasticizer, dispersant and/or compatibilizer alone makes it possible to reduce the phenomenon of salting out almost as much. For the wax-EVA (FIG. 8A), the plasticizer, dispersant and/or compatibilizer alone reduces the release but the addition of peroxide is a plus. Finally, without the presence of plasticizer, dispersant and/or compatibilizer, the addition of the peroxide greatly reduces the release and often more than the plasticizer, dispersant and/or compatibilizer alone or the peroxide-plasticizer, dispersant and/or compatibilizer mixture.

BIBLIOGRAPHY

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Claims

1. Masterbatch obtained by extrusion, comprising at least one thermoplastic polymer and at least one polymer of the ionene type which comprises, in its main chain, a sequence of repeating units, which are identical or different, each unit being chosen from the unit of formula (III) and the unit of formula (IV):

-N ⁺ (R1)(R2)-AN ⁺ (R3)(R4)-B-(III)

-N ⁺ (R3)(R4)-AN ⁺ (R1)(R2)-B- (IV) in which

- RI, R2, R3 and R4, identical or different, represent an optionally substituted alkyl group or an optionally substituted aryl group;

- A is a chain chosen from the group consisting of an optionally substituted alkylene chain, an optionally substituted alkenylene or alkynylene chain, an optionally substituted arylene chain, an optionally substituted alkylarylene chain and an optionally substituted arylalkylene chain; and

- B is a chain chosen from the group consisting of an optionally substituted alkylene chain, an optionally substituted alkenylene or alkynylene chain, an optionally substituted arylene chain, an optionally substituted alkylarylene chain and an optionally substituted arylalkylene chain.

2. Masterbatch according to claim 1, characterized in that said at least thermoplastic polymer is chosen from the group consisting of polyamides; saturated polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); polyvinyl chloride (PVC); polyolefins; styrenic polymers such as polystyrene (PS) and acrylonitrile butadiene styrene (ABS); and poly(meth)acrylates such as polymethyl methacrylate (PMMA) as well as combinations or mixtures thereof.

3. Masterbatch according to claim 1 or 2, characterized in that said at least thermoplastic polymer is a polyolefin chosen from the group consisting of polyethylene (PE), low density polyethylene (PEBD or LDPE), low density polyethylene linear (LDPE or LLPDE), high density polyethylene (HDPE or HDPE), polypropylene (PP), polymethylpentene (PMP) and polybutene-1 (PB-1).

4. Masterbatch according to any one of claims 1 to 3, characterized in that the total quantity of said at least one thermoplastic polymer in said masterbatch is between 50% and 98% by mass, in particular between 70% and 97% by mass and, in particular, between 80% and 96% by mass relative to the mass of said masterbatch.

5. Masterbatch according to any one of claims 1 to 4, characterized in that said at least ionene-type polymer comprises, in its main chain, a sequence of repeating units, which are identical or different, each unit being of formula ( III):

-N ⁺ (R1)(R2)-AN ⁺ (R3)(R4)-B- (III) in which

- A represents an alkylene comprising from 3 to 12 carbon atoms and in particular 6 carbon atoms,

- B represents an alkylene comprising from 3 to 12 carbon atoms and in particular 6 carbon atoms, and

- the radicals RI, R2, R3 and R4, which are identical or different, represent a methyl or an ethyl.

6. Masterbatch according to any one of claims 1 to 5, characterized in that the total amount of said at least one ionene-type polymer in said masterbatch is between 0.5% and 50% by mass, in particular between 1% and 30% by mass and, in particular, between 2% and 10% by mass relative to the mass of said masterbatch.

7. Masterbatch according to any one of claims 1 to 6, characterized in that said masterbatch further comprises at least one additive.

8. Masterbatch according to claim 7, characterized in that said at least one additive is at least one dispersing and/or compatibilizing plasticizer and/or at least one agent producing radical species.

9. Masterbatch according to claim 7 or 8, characterized in that the amount of said at least one additive in said masterbatch is between 0.05% and 30% by mass and in particular between 0.1% and 20% by mass relative to the mass of said masterbatch.

10. Process for the preparation of a masterbatch according to any one of claims 1 to 9, characterized in that it comprises the extrusion of a mixture comprising at least one thermoplastic polymer, at least one polymer of the ionene type and optionally at least one additive at a temperature less than or equal to 250°C, whereby a masterbatch comprising at least one thermoplastic polymer, at least one polymer of ionene type and optionally at least one additive is obtained.

11. Method according to claim 10, characterized in that said extrusion is a reactive extrusion.

12. Article having bacteriostatic or bactericidal properties prepared from a masterbatch according to any one of claims 1 to 9.

13. Article according to claim 12, characterized in that said article is chosen from the group consisting of a film, a packaging film, a box, a tray, a bottle, a case, a case, a lid, a sachet , dialysis equipment, rod, probe, membrane and filter.

14. Process for preparing an article according to claim 12 or 13, said process comprising the transformation of the masterbatch according to any one of claims 1 to 9 optionally mixed with a thermoplastic resin into an article.

15. Preparation process according to claim 14, characterized in that it comprises mixing the masterbatch according to any one of claims 1 to 9 with a thermoplastic resin, whereby a thermoplastic composition is obtained and then converting this thermoplastic composition into said article.