EP4359226A1

EP4359226A1 - Inner sealing layer for a tyre against the proliferation of mosquitoes

Info

Publication number: EP4359226A1
Application number: EP22744263.9A
Authority: EP
Inventors: Aurore CROCHET; José-Carlos ARAUJO DA SILVA; Mathilde TOUSTOU; Salvatore Pagano; Stéphanie LAUBE
Original assignee: Compagnie Generale des Etablissements Michelin SCA
Current assignee: Compagnie Generale des Etablissements Michelin SCA
Priority date: 2021-06-23
Filing date: 2022-06-22
Publication date: 2024-05-01
Also published as: FR3124518A1; FR3124518B1; WO2022269194A1

Abstract

The present invention relates to an inner sealing layer for a tyre, comprising copper(II) gluconate for preventing or eradicating the proliferation of insects, in particular mosquito larvae present in stagnant water in the tyre.

Description

Inner waterproof layer for tires against the proliferation of mosquitoes FIELD OF THE INVENTION

The present invention relates to the use of a particular copper salt in a rubber composition used in the manufacture of a tire and which prevents the proliferation of mosquitoes, in particular when the said tire can constitute a reservoir of stagnant water (storage or discharge outdoors).

More specifically, the invention relates to an inner waterproof layer for a tire having a rubber composition comprising copper (II) gluconate.

STATE OF THE ART The problem of the end of life of tires does not arise at all in the same way in temperate zones and zones with a high industrial concentration compared to tropical zones with little infrastructure. In the first case, recovery channels are in place to supply and support a recovery chain. In the second case, there is almost no or very little recovery circuit and very often tires at the end of their life are thrown into wild dumps, whether by private individuals or even professional repairers.

Discarded in landfill and subjected to external conditions, these tires constitute containers where rainwater will be retained and stagnate.

The multiple beds of stagnant water thus formed contribute to the massive proliferation of mosquitoes which themselves are the vector of many infectious diseases such as malaria, yellow fever, West Nile fever, dengue fever, the zika virus or even chikungunya.

Making sure to incorporate an insecticide on the surface or in the tire in contact with water leads to an effect but which disappears over time because the larvae and mosquitoes end up becoming resistant.

Application EP 3 498 493 proposes a tire comprising a layer intended to prevent or prevent the proliferation of mosquitoes. This layer can be an inner layer, an area adjacent to an inner layer or an outer layer of the tire. The chemical compound having repellent/insecticidal properties can be deposited on one of these layers or mixed with one of these layers. This chemical compound is also defined very broadly and includes many compounds of different natures, including copper-based compounds. Indeed, copper salts are known for their biocidal properties, in particular vis-à-vis mosquito larvae. However, all the chemical compounds mixed with a rubber composition will not be able to migrate within the rubber composition in order to be able to be released and play their role against the proliferation of insects, in particular mosquitoes or their larvae. Through her research, the applicant has found a means of circumventing this disadvantage of resistance to insecticides by acting on the process of respiration and nutrition of insect larvae, in particular mosquito larvae, during their development. The invention is based on the use of a particular copper (II) salt in the composition of the inner waterproof layer which is able by contact to transfer copper (II) to the rainwater which accumulates in the tire.

DISCLOSURE OF THE INVENTION

The first subject of the invention is an inner waterproof layer for a tire having a rubber composition based on at least:

- an elastomeric matrix comprising at least 50 phr of one or more butyl rubbers;

- 5 phr of one or more reinforcing fillers;

- from 0 to 40 phr of a plasticizer; characterized in that the rubber composition further comprises copper (II) gluconate. Advantageously, the rubber composition comprises at least 0.5 phr, preferably up to 15 phr of copper (II) gluconate, in particular from 0.5 to 15 phr of copper (II) gluconate, more preferably from 0 .75 to 12 pc.

The butyl rubber(s) are advantageously chosen from isobutylene rubbers, copolymers of isobutylene and isoprene, bromobutyl rubbers such as bromoiisobutylene-isoprene copolymer, chlorobutyl rubbers such as chloroisobutylene-isoprene copolymer, and copolymers of isobutylene and styrene derivatives such as copolymers of isobutylene and brominated methylstyrene.

The elastomeric matrix can comprise 100 phr of one or more butyl rubbers.

In another variant, the elastomeric matrix comprises up to 50 phr of a diene elastomer other than butyl rubber. The diene elastomer other than butyl rubber is advantageously chosen from polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

In particular, the diene elastomer other than butyl rubber is chosen from polybutadienes, synthetic polyisoprenes, natural rubber, butadiene-styrene copolymers, isoprene-butadiene copolymers, isoprene-styrene copolymers, isoprene-butadiene-styrene copolymers and mixtures of these elastomers.

Advantageously, the rubber composition comprises a reinforcing filler chosen from carbon black, a reinforcing inorganic filler such as silica or a mixture of these fillers.

The rubber composition preferably comprises 10 to 100 phr of reinforcing filler.

The rubber composition may comprise an additional filler chosen from the group consisting of semi-reinforcing fillers, inert fillers and mixtures of these fillers.

The additional filler is advantageously chosen from the group consisting of graphite, kaolin, chalk, talc and their combinations.

The plasticizer is advantageously chosen from plasticizing oils, plasticizing resins or combinations thereof.

Advantageously, the rubber composition is based on a sulfur crosslinking system.

The invention also relates to a tire comprising an inner waterproof layer as defined previously and subsequently.

The invention also relates to the use of copper (II) gluconate in a rubber composition for tires for preventing or eradicating the proliferation of insects, in particular mosquito larvae present in water stagnant in the tire.

DEFINITIONS

The expression "composition based on" means a composition comprising the mixture and/or the in situ reaction product of the various constituents used, some of these constituents being able to react and/or being intended to react with one another, less partially, during the various phases of manufacture of the composition; the composition thus possibly being in the totally or partially crosslinked state or in the non-crosslinked state.

By the expression "part by weight per hundred parts by weight of elastomer" (or phr), is meant within the meaning of the present invention, the part, by mass per hundred parts by mass of elastomer.

The term "inner tight layer" means a layer tight to gases, namely to air and to any inflation gas, which is found in a conventional pneumatic tire of the "tubeless" type, i.e. say tubeless. In a conventional pneumatic tire of the "tubeless" type, the radially inner face, also called the radially inner face, comprises a layer impermeable to air (or more generally to any inflation gas) which allows inflation and maintenance under pressure of the tire. pneumatic tire. Its sealing properties allow it to guarantee a relatively low rate of pressure loss, allowing the bandage to be kept inflated in normal working condition for a sufficient period of time, normally several weeks or several months. It also has the function of protecting the carcass reinforcement and more generally the rest of the tire from a risk of oxidation due to the diffusion of air from the space inside the tire. This function of sealed inner layer or “inner rubber” (“inner liner”) is today fulfilled by compositions based on butyl rubber, recognized for a very long time for their excellent sealing properties.

The terms "gas-tight layer", "inner tight layer", "inner tight layer", "tight layer", "inner layer", "inner layer", "inner rubber" are, within the meaning of the invention, synonyms.

By "butyl rubber" is meant an isobutylene homopolymer or a copolymer of isobutylene and isoprene, as well as the halogenated derivatives, in particular generally brominated or chlorinated, of these isobutylene homopolymers and copolymers of isobutylene and isoprene. By extension of the preceding definition, the term “butyl rubber” will also include copolymers of isobutylene and of styrene derivatives.

By “elastomeric matrix” within the meaning of the present invention, is meant all of the elastomers (or rubbers) of the rubber composition. Thus, the matrix elastomer can in particular consist of a single elastomer but also of a blend of two or more elastomers; these elastomers possibly being diene elastomers and/or thermoplastic elastomers, preferably these elastomers are diene elastomers. By diene elastomer (or indistinctly rubber), whether natural or synthetic, must be understood in a known manner an elastomer consisting at least in part (ie, a homopolymer or a copolymer) of diene monomer units (monomers bearing two double carbon-carbon bonds, conjugated or not).

By reinforcing inorganic filler, should be understood here any inorganic or mineral filler, whatever its color and its origin (natural or synthetic), also called white filler, clear filler or even non-black filler as opposed to carbon black, capable of reinforcing on its own, without any means other than an intermediate coupling agent, a rubber composition intended for the manufacture of tires. In a known manner, certain reinforcing inorganic fillers can be characterized in particular by the presence of hydroxyl groups (—OH) at their surface.

By graphite, we generally mean a collection of stacked graphene planes, graphene being an atomic-thick sheet in which the carbon atoms are organized in an essentially hexagonal lattice. “Plasticizer” means a compound that is liquid or solid at room temperature (23° C.) and at atmospheric pressure (1.013.10 ⁵ Pa) that is compatible, that is to say miscible at the rate used with the rubber composition at which it is intended, so as to act as a thinning agent.

The compounds mentioned in the description can be of fossil origin or biosourced. In the latter case, they can be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. Obviously, the compounds mentioned can also come from the recycling of materials already used, that is to say that they can be, partially or totally, from a recycling process, or even obtained from raw materials themselves. even from a recycling process. This concerns in particular polymers, plasticizers, fillers, etc.

DESCRIPTION OF FIGURES

FIG. 1 very schematically shows a radial section of a pneumatic tire according to the invention. The previously defined gas-tight layer can advantageously be used in the tires of all types of vehicles, in particular passenger vehicles or industrial vehicles such as heavy goods vehicles.

By way of example, fig. 1 appended represents very schematically (without respecting a specific scale), a radial section of a pneumatic tire according to the invention.

This pneumatic tire 1 comprises a crown 2 reinforced by a crown reinforcement or belt 6, two sidewalls 3 and two beads 4, each of these beads 4 being reinforced with a bead wire 5. The crown 2 is surmounted by a tread not shown in this schematic figure. A carcass reinforcement 7 is wound around the two bead wires 5 in each bead 4, the upturn 8 of this reinforcement 7 being for example arranged towards the outside of the tire 1 which is shown here mounted on its rim 9. The carcass reinforcement 7 is in a manner known per se consisting of at least one ply reinforced by so-called radial cables, for example textile or metal, that is to say that these cables are arranged practically parallel to each other and extend from one bead to the other so as to form an angle of between 80° and 90° with the median circumferential plane (plane perpendicular to the axis of rotation of the tire which is located halfway between the two beads 4 and passes through the middle of the top frame 6). The inner wall of the pneumatic tire 1 comprises an airtight layer 10, for example of thickness equal to approximately 0.9 mm, on the side of the inner cavity 11 of the pneumatic tire 1.

This waterproof layer covers the entire inner wall of the tire, extending from sidewall to sidewall, at least up to the level of the rim hook when the tire is in the mounted position. It defines the radially internal face of said tire intended to protect the carcass reinforcement from the diffusion of air coming from the space 11 inside the tire. It allows the tire to be inflated and maintained under pressure; its sealing properties must enable it to guarantee a relatively low rate of pressure loss, to keep the tire inflated, in normal working order, for a sufficient period of time, normally several weeks or several months.

An advantageous manufacturing variant, for those skilled in the art of pneumatic tires, consists, for example, during a first step, in depositing the airtight layer flat directly on a building drum, in the form of a layer ("skim") of suitable thickness, before covering the latter with the rest of the tire structure, according to manufacturing techniques well known to those skilled in the art.

DETAILED DESCRIPTION OF THE INVENTION The subject of the invention is an inner waterproof layer for a tire having a rubber composition based on at least:

- 5 phr of one or more reinforcing fillers; - from 0 to 40 phr of a plasticizer; characterized in that the rubber composition further comprises copper (II) gluconate.

Copper (II) gluconate is also referred to as copper (2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanoate. Copper (II) gluconate is the salt of D-gluconic acid HOH2C-(CHOH)4-COOH and copper (II) Cu ²⁺ . Copper is chelated by two D-gluconic acid ligands.

The rubber composition advantageously comprises at least 0.5 phr of copper (II) gluconate, preferably up to 15 phr of copper (II) gluconate, in particular from 0.5 to 15 phr of copper (II) gluconate ), more preferably from 0.75 to 12 phr. The literature indicates that a copper concentration of between 500 ppb and 80 ppm in water is able to block the growth of larvae, in particular mosquito larvae, and therefore to present a larvicidal character.

Of all the copper salts tested, only copper(II) gluconate, when incorporated into an inner waterproof layer rubber composition, is capable of releasing copper into water in contact with said composition. The concentration of copper (II) in the water is consistent with a mosquito larviciding effect. In fact, a tire comprising as an inner waterproof layer this type of composition and in particular dumped in the wild or reused for any other application different from its primary destination (for example to hold silage tarpaulins), could make it possible to fight against the proliferation of mosquitoes by stagnation of rainwater inside the tyre.

Furthermore, the introduction of this copper gluconate does not modify the process for manufacturing a rubber composition for tires. In particular, the rubber composition for the inner waterproof layer retains its ability to be cured, that is to say its ability to be crosslinked or vulcanized, which makes it possible to envisage the manufacture of such compositions on usual industrial manufacturing tools.

In addition, the introduction of this copper gluconate does not modify the mechanical properties of the composition of the inner waterproof layer, which allows the properties of the tire to be maintained during its service.

The rubber composition comprises the usual components of a composition for an inner waterproof layer, namely:

- an elastomeric matrix comprising at least 50 phr of one or more butyl rubbers; - at least 5 phr of one or more reinforcing fillers;

- from 0 to 40 phr of a plasticizer;

- optionally an additional filler chosen from semi-reinforcing fillers and inert fillers;

- optionally a crosslinking system; - optionally all or part of the usual additives usually used in elastomer compositions intended for the manufacture of tires.

Preferably, the butyl rubber(s) that can be used are chosen from isobutylene rubbers, copolymers of isobutylene and isoprene (IIR), bromobutyl rubbers such as bromoiisobutylene-isoprene copolymer (BIIR), chlorobutyl rubbers such as chloroisobutylene-isoprene copolymer (CMR), copolymers of isobutylene and of styrene derivatives such as copolymers of isobutylene and brominated methylstyrene (BIMS) of which the elastomer named EXXPRO, marketed by the company Exxon, forms part.

Particularly preferably, the butyl rubber or rubbers that can be used are chosen from isobutylene rubbers and copolymers of isobutylene and isoprene.

The butyl rubber(s) which can be used in the inner rubber of the present invention represent at least 50 phr, that is to say they represent at least 50% by weight of the total weight of the elastomeric matrix.

As other elastomers present in the elastomeric matrix in addition to the butyl rubber(s), mention may in particular be made of elastomers, in particular diene elastomers other than the butyl elastomers mentioned above.

These diene elastomers can be classified into two categories: “essentially unsaturated” or “essentially saturated”. The term “essentially unsaturated” generally means a diene elastomer derived at least in part from diene monomers conjugates, having a content of units or units of diene origin (conjugated dienes) which is greater than 15% (% in moles); thus diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins of the EPDM type do not fall within the above definition and may in particular be qualified as "essentially saturated" diene elastomers (rate of units of weak or very weak diene origin, always less than 15% in moles).

In the present application, the diene elastomers are by definition non-thermoplastic.

By diene elastomer capable of being used in the compositions in accordance with the invention is meant in particular:

(a) any homopolymer of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms;

(b) any copolymer of a diene, conjugated or not, having 4 to 18 carbon atoms and at least one other monomer.

The other monomer can be ethylene, an olefin or a diene, conjugated or not.

Suitable conjugated dienes are conjugated dienes having from 4 to 12 carbon atoms, in particular 1,3-dienes, such as in particular 1,3-butadiene and isoprene.

Suitable non-conjugated dienes are non-conjugated dienes having 6 to 12 carbon atoms, such as 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene.

Suitable olefins are vinylaromatic compounds having 8 to 20 carbon atoms and aliphatic α-monoolefins having 3 to 12 carbon atoms.

Suitable vinylaromatic compounds are, for example, styrene, ortho-, meta-, para-methylstyrene, the commercial “vinyl-toluene” mixture, para-tert/obutylstyrene.

Suitable aliphatic α-monoolefins are in particular acyclic aliphatic α-monoolefins having from 3 to 18 carbon atoms.

More particularly, the diene elastomer is:

(a’) any homopolymer of a conjugated diene monomer, in particular any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms;

(b') any copolymer obtained by copolymerization of one or more conjugated dienes with one another or with one or more vinylaromatic compounds having from 8 to 20 carbon;

(c') any copolymer obtained by copolymerization of one or more dienes, conjugated or not, with ethylene, an α-monoolefin or their mixture such as for example the elastomers obtained from ethylene, propylene with a diene monomer unconjugated of the aforementioned type.

Preferably, the diene elastomer is chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers. Among these polybutadienes, polybutadienes having a rate (% molar) of cis-1,4 bonds greater than 90%, more preferably still greater than 96%, are preferably used.

Among these synthetic polyisoprenes, polyisoprenes having a rate (% molar) of cis-1,4 bonds greater than 90%, more preferably still greater than 98%, are preferably used.

Among the isoprene copolymers, mention will be made in particular of isoprene-styrene copolymers (SIR), isoprene-butadiene copolymers (BIR) or isoprene-butadiene-styrene copolymers (SBIR).

Among the butadiene copolymers, mention will be made in particular of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR) or isoprene-butadiene-styrene copolymers (SBIR).

Even more preferably, the diene elastomer is chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene-styrene copolymers and mixtures of these elastomers. The diene elastomer can be modified, that is to say either coupled and/or star-shaped, or functionalized, or coupled and/or star-shaped and simultaneously functionalized.

Thus, the diene elastomer can be coupled and/or starred, for example by means of a silicon or tin atom which binds the elastomer chains together.

The diene elastomer can be simultaneously or alternately functionalized and comprise at least one functional group. By functional group is meant a group comprising at least one heteroatom chosen from Si, N, S, O, P. he

In summary, the butyl rubber of the composition in accordance with the invention is preferably chosen from the group of essentially saturated diene elastomers consisting of copolymers of isobutene and isoprene and their halogenated derivatives, this essentially saturated elastomer being able to be used in blending with an elastomer chosen from the group of highly unsaturated diene elastomers consisting of polybutadienes (abbreviated as "BR"), synthetic polyisoprenes (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers; more preferably still, this essentially saturated elastomer can be used in blending with an elastomer chosen from the group of highly unsaturated diene elastomers consisting of polybutadienes (abbreviated as "BR"), synthetic polyisoprenes (IR), natural rubber (NR) , butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR), isoprene-butadiene-styrene copolymers (SBIR) and mixtures of these elastomers. Preferably, the content of butyl rubber ranges from 60 to 100 phr, preferably from 65 to 100 phr, more preferably from 70 to 100 phr.

According to one variant embodiment of the invention, the composition also comprises a diene elastomer as mentioned above with a content of 0 to 40 phr of these elastomers, preferably from 0 to 35 phr, more preferably from 0 to 30 phr. According to another preferred variant of the invention, the composition comprises only a butyl rubber or a mixture of butyl rubbers.

The rubber composition comprises at least 5 phr of a reinforcing filler.

The rubber composition of the invention may comprise one or more reinforcing fillers.

It is possible to use any type of so-called reinforcing filler, known for its ability to reinforce a rubber composition which can be used in particular for the manufacture of tires, for example an organic filler such as carbon black, a reinforcing inorganic filler such as silica or again a mixture of these two types of fillers.

Suitable carbon blacks are all carbon blacks, in particular the blacks conventionally used in tires or their treads. Among the latter, mention will be made more particularly of the reinforcing carbon blacks of the series 100, 200, 300, or 500, 600 or 700 series blacks (ASTM D-1765-2017 grades), such as blacks N115, N134, N234, N326, N330, N339, N347, N375, N550, N683 , N772). These carbon blacks can be used in the isolated state, as commercially available, or in any other form, for example as a carrier for some of the rubber additives used. The carbon blacks could for example already be incorporated into the diene elastomer, in particular isoprene in the form of a masterbatch (see for example applications W097/36724-A2 or W099/16600-A1).

As an example of organic fillers other than carbon blacks, mention may be made of functionalized polyvinyl organic fillers as described in applications W02006/069792-A1, W02006/069793-A1, W02008/003434-A1 and W02008/003435-A1 .

Suitable reinforcing inorganic fillers are in particular mineral fillers of the siliceous type, preferably silica (S1O2) or of the aluminous type, in particular alumina (A 03). The silica used can be any reinforcing silica known to those skilled in the art, in particular any precipitated or fumed silica having a BET specific surface area as well as a CTAB specific surface area, both of which are less than 450 m ² /g, preferably comprised in a range ranging from 30 to 400 m ² /g, in particular from 60 to 300 m ² /g.

It is possible to use any type of precipitated silica, in particular highly dispersible precipitated silicas (called “HDS” for “highly dispersible” or “highly dispersible silica”). These precipitated silicas, highly dispersible or not, are well known to those skilled in the art. Mention may be made, for example, of the silicas described in applications WO03/016215-A1 and WO03/016387-A1. Among the commercial HDS silicas, it is possible in particular to use the “Ultrasil® 5000GR”, “Ultrasil® 7000GR” silicas from the company Evonik, the “Zeosil® 1085GR”, “Zeosil® 1115 MP”, “Zeosil® 1165MP”, “Zeosil® 1165MP” silicas, Zeosil® Premium 200MP”, “Zeosil® HRS 1200 MP” from Solvay. As non-HDS silica, the following commercial silicas can be used: “Ultrasil® VN2GR” and “Ultrasil® VN3GR” silicas from Evonik, “Zeosil® 175GR” silica from Solvay, “Hi- Sil EZ120G(-D)", "Hi-Sil EZ160G(-D)", "Hi-Sil EZ200G(-D)", "Hi-Sil 243LD", "Hi-Sil 210", "Hi-Sil HDP 320G from PPG. As other examples of inorganic fillers capable of being used in the rubber compositions of the invention, mention may also be made of mineral fillers of the alumina type, in particular alumina (Al2O3), aluminum oxides, aluminum hydroxides, aluminosilicates, titanium oxides, silicon carbides or nitrides, all of the reinforcing type as described for example in applications W099/28376-A2, WOOO/73372-A1, W002/053634-A1 , W02004/003067-A1 , W02004/ 056915-A2, US6610261-B1 and US6747087-B2. Mention may in particular be made of the aluminas “Baikalox A125” or “CR125” (Baïkowski company), “APA-100RDX” (Condéa Vista Company), “Aluminoxid C” (Evonik) or “AKP-G015” (Sumitomo Chemicals).

The physical state in which the reinforcing inorganic filler is present is irrelevant, whether it be in the form of powder, microbeads, granules, or else beads or any other appropriate densified form. Of course, the term “reinforcing inorganic filler” also means mixtures of different reinforcing inorganic fillers, in particular of silicas as described above.

Those skilled in the art will understand that replacing the reinforcing inorganic filler described above, a reinforcing filler of another nature could be used, since this reinforcing filler of another nature would be covered with an inorganic layer. such as silica, or else would comprise functional sites, in particular hydroxyl sites, on its surface, requiring the use of a coupling agent to establish the bond between this reinforcing filler and the diene elastomer. By way of example, mention may be made of carbon blacks partially or completely covered with silica, or carbon blacks modified with silica, such as, without limitation, fillers of the "Ecoblack®" type of the series “CRX2000” or “CRX4000” series from Cabot Corporation.

A person skilled in the art will be able to adapt the total reinforcing filler content according to the use concerned, in particular according to the type of tire concerned, for example tire for a motorcycle, for a passenger vehicle or even for a utility vehicle such as a van or heavy goods vehicle. Preferably, this content of total reinforcing filler is within a range ranging from 10 to 100 phr, more preferably from 15 to 100 phr, and even more preferably from 20 to 80 phr; the optimum being in a known manner different according to the particular applications targeted.

The carbon black can advantageously constitute the sole reinforcing filler or the majority reinforcing filler by mass. By majority by mass, it is meant that the carbon black represents more than 50% by mass of the total mass of the reinforcing filler, more preferentially more than 55% by mass, more preferentially still more than 60% by mass.

In this disclosure, BET surface area is determined by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" (Vol. 60, page 309, February 1938) , and more specifically according to a method adapted from standard NF ISO 5794-1 , appendix E of June 2010 [method multipoint volumetric (5 points) - gas: nitrogen - vacuum degassing: one hour at 160°C - range of relative pressure p/po: 0.05 to 0.17].

For inorganic fillers such as silica for example, the CTAB specific surface values were determined according to standard NF ISO 5794-1, appendix G of June 2010. The process is based on the adsorption of CTAB (N-bromide hexadecyl-N,N,N-trimethylammonium) on the "external" surface of the reinforcing filler.

For carbon blacks, the STSA specific surface area is determined according to the ASTM D6556-2016 standard.

To couple the reinforcing inorganic filler to the diene elastomer, it is possible to use, in a well-known manner, an at least bifunctional coupling agent (or bonding agent) intended to ensure a sufficient connection, of a chemical and/or physical nature, between the filler inorganic (surface of its particles) and diene elastomer. In particular, at least bifunctional organosilanes or polyorganosiloxanes are used. By "bifunctional" is meant a compound having a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer. For example, such a bifunctional compound may comprise a first functional group comprising a silicon atom, said first functional group being capable of interacting with the hydroxyl groups of an inorganic filler and a second functional group comprising a sulfur atom, said second functional group being capable of interacting with the diene elastomer.

Preferably, the organosilanes are chosen from the group consisting of polysulphide organosilanes (symmetrical or asymmetrical) such as bis(3-triethoxysilylpropyl) tetrasulphide, abbreviated as TESPT marketed under the name “Si69” by the company Evonik or bis disulphide -(triethoxysilylpropyl), abbreviated as TESPD marketed under the name “Si75” by the company Evonik, polyorganosiloxanes, mercaptosilanes, blocked mercaptosilanes, such as S-(3-(triethoxysilyl)propyl) octanethioate marketed by the company Momentive under the name “NXT Silane”. More preferably, the organosilane is a polysulphide organosilane. Of course, mixtures of the coupling agents described above could also be used.

The content of coupling agent in the composition of the invention is advantageously less than or equal to 35 phr, it being understood that it is generally desirable to use as little as possible. Typically the rate of coupling agent represents from 0.5% to 15% in weight relative to the amount of reinforcing inorganic filler. Its content is preferably within a range ranging from 0.5 to 20 phr, more preferably within a range ranging from 2 to 10 phr. This rate is easily adjusted by those skilled in the art according to the rate of reinforcing inorganic filler used in the composition.

The composition of the invention can also comprise another filler, called additional filler, which can be chosen from the group consisting of semi-reinforcing fillers, inert fillers and mixtures of these fillers. Preferably, this additional filler can be a semi-reinforcing filler such as graphite.

Semi-reinforcing fillers are not capable of reinforcing by themselves a rubber composition intended for the manufacture of tires, in other words they are not suitable for replacing, in its reinforcing function, a conventional carbon black of pneumatic grade, however they allow an increase in the tensile modulus of a rubber composition in which they are incorporated, which is why they are called semi-reinforcing.

As semi-reinforcing filler optionally present in the composition, mention may in particular be made of graphite. The term "graphite capable of being used in the context of the invention" is understood more particularly:

(i) any natural graphite, associated with rocks affected by metamorphism, after separation of the impurities accompanying the graphite veins and after grinding;

(ii) any thermally expandable natural graphite, i.e. in which a chemical compound in the liquid state, for example an acid, is intercalated between its graphene planes;

(iii) any expanded natural graphite, the latter being produced in two stages: intercalation of a chemical compound in the liquid state, for example an acid, between the graphene planes of a natural graphite by chemical treatment and expansion at high temperature ;

(iv) any synthetic graphite. The rubber composition which can be used according to the invention may contain a single graphite or a mixture of several graphites, thus for example there may be a blend of natural graphite and/or of expanded graphite and/or of synthetic graphite. Graphite as defined previously, can be present on a morphological level in a lamellar form or not.

Preferably, the graphite that can be used according to the invention is in lamellar form. Preferably, the content of the semi-reinforcing filler(s), in particular graphite, in the rubber composition of the invention is within a range ranging from 0 to 35 phr, preferably from 1 to 35 phr, and even more preferably from 1 to 20 phr.

The composition of the invention may also comprise an inert filler. By inert fillers is meant non-reinforcing fillers.

Among the inert fillers well known to those skilled in the art, mention will be made in particular of those chosen from the group consisting of microparticles of natural (chalk) or synthetic calcium carbonates, synthetic or natural silicates (such as kaolin, talc , mica, vermiculite), alumino-silicates (clay, bentonite, montmorillonite), glass microbeads, glass flakes and a mixture of these compounds.

Preferably, the content of the inert filler(s), in the rubber composition of the invention, is within a range ranging from 1 to 40 phr, preferably ranging from 2 to 30 phr, more preferably still ranging from 2 at 25 pc. The aforementioned inert fillers are in fact particularly interesting because they make it possible to improve the impermeability of the compositions in which they are dispersed with an adequate rate.

Suitable in particular as inert fillers are lamellar mineral fillers based on silicon. In particular, among the lamellar mineral fillers based on silicon, suitable are phyllosilicates and particularly those included in the group consisting of smectites, kaolin, talc, mica and vermiculite.

Among the phyllosilicates also suitable for the invention, the functionalized and in particular organo-modified phyllosilicates. According to a particular embodiment, the organic structure with which the inert filler is associated is a surfactant of formula: -M+R ^c R ^d R ^e - , where M represents a nitrogen, sulfur, phosphorus or pyridine and where R ^c , R ^d , and R ^e each represent a hydrogen atom, an alkyl group, an aryl group or an allyl group, R ^c , R ^d , and R ^e being identical or different. In particular, organo-modified montmorillonites are suitable for the invention.

Thus montmorillonites modified with a surfactant such as a dioctadecyldimethyl-dihydrogenated quaternary ammonium salt. Such an organo-modified montmorillonite is marketed in particular by the company Southern Clay Products under the trade name “CLOISITE 6A” and “CLOISITE 20A”.

Other surfactants based on quaternary ammonium salts can also be used to modify the phyllosilicates as described in patent application WO2006/047509-A2.

The chalk is preferably in the form of microparticles whose average size (by mass) is greater than 1 μm. The median size of the chalk microparticles, measurement obtained on a sedigraph, is preferentially within a range ranging from 0.5 to 200 μm, more particularly from 0.5 to 30 μm and even more preferentially from 1 to 20 μm.

The chalks known to those skilled in the art are natural (chalk) or synthetic calcium carbonates with or without coating (for example with stearic acid).

As examples of such preferred and commercially available chalks, mention may be made, for example, of the chalk sold under the name “Omya BLS” by the company Omya.

Advantageously, the composition comprises at least one reinforcing filler and optionally an additional filler chosen from a semi-reinforcing filler, an inert filler and combinations thereof.

Advantageously, the composition comprises at least carbon black and optionally an additional filler chosen from graphite, kaolin, chalk, talc and their combinations.

The rubber composition that can be used in the inner waterproof layer comprises from 0 to 40 phr of a plasticizer.

Preferably, the plasticizer is chosen from plasticizing oils, plasticizing resins or combinations thereof.

By definition, a plasticizing oil (also called liquid plasticizer) is liquid at room temperature and atmospheric pressure. This or these plasticizing oils generally have a low glass transition temperature, lower than -20° C. (Tg, measured according to ASTM D3418-1999), preferably lower than -40° C. The temperatures of glass transition are measured in a known manner by DSC (“Differential Scanning Calorimetry”) according to standard ASTM D3418-1999.

As plasticizing oil, it is possible to use all the so-called “extender” oils, whether aromatic or non-aromatic in nature, known for their plasticizing properties with respect to the elastomers used.

The plasticizing oils chosen from the group consisting of liquid diene polymers, polyolefinic oils, naphthenic oils, paraffinic oils, DAE oils (Distillate Aromatic Extracts), MES oils (Medium Extracted Solvates), TDAE oils ( Treated Distillate Aromatic Extracts), RAE oils (Residual Aromatic Extracts), TRAE oils (Treated Residual Aromatic Extracts), SRAE oils (Safety Residual Aromatic Extracts), mineral oils, vegetable oils, ether plasticizers, ester plasticizers , phosphate plasticizers, sulfonate plasticizers and mixtures of these compounds.

Also suitable are liquid polymers derived from the polymerization of olefins or dienes, such as those chosen from the group consisting of polybutenes, polydienes, in particular polybutadienes, polyisoprenes, copolymers of butadiene and isoprene, copolymers of butadiene or isoprene and styrene, and mixtures of these liquid polymers. The number-average molar mass of such liquid polymers is preferably within a range ranging from 500 g/mol to 50,000 g/mol, more preferably from 1,000 g/mol to 10,000 g/mol. By way of example may be mentioned in particular the "Ricon" products of the company Cray Valley

Also suitable are polyisobutylene oils, functionalized or not, having a molecular weight of between 200 g/mol and 40,000 g/mol.

According to another embodiment, the plasticizing oil(s) are vegetable oils (such as linseed, safflower, soya, corn, cottonseed, rape, castor, tung, pine, sunflower, palm, olive, coconut, peanut , grapeseed, and mixtures of these oils, in particular a sunflower oil).

According to another embodiment, the plasticizing oil or oils are an ether such as, for example, polyethylene glycols or polypropylene glycols. Also suitable are plasticizing oils chosen from the group consisting of ester plasticizers, phosphate plasticizers, sulfonate plasticizers and mixtures of these compounds.

The plasticizer can also be chosen from plasticizer resins. As opposed to plasticizing oils, plasticizing resin means a compound which is solid at room temperature (23° C.) and at atmospheric pressure (1.013×10 ⁵ Pa). This or these plasticizing resins generally have a glass transition temperature, greater than 20° C. (Tg, measured according to ASTM D3418-1999), preferably greater than 30° C.

Preferably, the plasticizing resins are hydrocarbon plasticizing resins.

Hydrocarbon resins are polymers well known to those skilled in the art, therefore miscible by nature in elastomer(s) compositions when they are further qualified as “plasticizers”.

These hydrocarbon plasticizing resins generally have a glass transition temperature above 20° C. and a softening temperature below 170° C.

Softening temperatures (“softening point”) are measured according to standard ASTM E-28.

They have been extensively described, for example, in the work entitled "Hydrocarbon Resins" by R. Mildenberg, M. Zander and G. Collin (New York, VCH, 1997, ISBN 3 -527-28617-9) of which chapter 5 is dedicated to their applications, particularly in pneumatic rubber (5.5. “Rubber Tires and Mechanical Goods”). They can be aliphatic, naphthenic, aromatic or else of the aliphatic/naphthenic/aromatic type, that is to say based on aliphatic and/or naphthenic and/or aromatic monomers. They can be natural or synthetic, petroleum-based or not (if so, they are also known as petroleum resins). They are preferably exclusively hydrocarbon-based, that is to say they contain only carbon and hydrogen atoms.

The plasticizer content in the rubber composition according to the invention varies from 0 to 40 phr, advantageously from 2 phr to 20 phr, more advantageously from 2 phr to 10 phr. The rubber composition that can be used in the inner waterproof layer can also comprise all or some of the usual additives usually used in elastomer compositions intended for the manufacture of tires, such as, for example, protective agents such as chemical anti-ozonants, anti- oxidants, anti-fatigue agents, acceptors (eg phenol novolac resin) or methylene donors (eg HMT or H3M).

The rubber composition that can be used in the inner waterproof layer can be manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art:

- a first working phase or thermomechanical mixing (so-called "non-productive" phase) which can be carried out in a single thermomechanical step during which, in a suitable mixer such as a usual internal mixer (for example of the “Banbury”), all the necessary constituents, in particular the elastomeric matrix, the fillers, any other miscellaneous additives, with the exception of the crosslinking system. The incorporation of the filler into the elastomer can be carried out in one or more stages by mixing thermomechanically. In the case where the filler is already incorporated in whole or in part in the elastomer in the form of a masterbatch (“masterbatch” in English) as described for example in the applications

W097/36724 or W099/16600, it is the masterbatch which is mixed directly and, if necessary, the other elastomers or fillers present in the composition which are not in the form of the masterbatch, as well as any other miscellaneous additives other than the crosslinking system. The non-productive phase can be carried out at high temperature, up to a maximum temperature of between 80° C. and 150° C., preferably between 100° C. and 140° C. for a period generally of between 2 and 10 minutes.

- then, a second phase of mechanical work (so-called "productive" phase) which is carried out in an external mixer such as a roller mixer, after cooling the mixture obtained during the first non-productive phase to a higher low temperature, typically below 120°C, for example between 40°C and 100°C. The crosslinking system is then incorporated, and the whole is then mixed for a few minutes, for example between 5 and 15 min.

Copper (II) gluconate can be introduced during the so-called non-productive phase and/or during the so-called productive phase.

The crosslinking system can be any type of system known to those skilled in the art in the field of rubber compositions for tires. It may in particular be based on sulfur and/or bismaleimides. The crosslinking system itself is advantageously sulfur-based. The crosslinking system is preferably based on sulphur, one then speaks of a vulcanization system. The sulfur can be provided in any form, in particular in the form of molecular sulfur, or of a sulfur-donating agent. At least one vulcanization accelerator, in particular an accelerator of the sulfenamide type, is also preferentially present, and, optionally, also preferentially, various known vulcanization activators can be used, such as zinc oxide, stearic acid or compound equivalent such as salts of stearic acid and salts of transition metals, guanidine derivatives (in particular diphenylguanidine), or alternatively known vulcanization retarders. The sulfur is used at a preferential rate of between 0.5 and 12 phr, in particular between 1 and 10 phr. The vulcanization accelerator is used at a preferential rate comprised between 0.1 and 10 phr, more preferentially comprised between 0.2 and 5.0 phr.

Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur can be used as an accelerator, in particular accelerators of the thiazole type as well as their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate type. As examples of such accelerators, mention may be made in particular of the following compounds: 2-mercaptobenzothiazyl disulphide (abbreviated to "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide (abbreviated to "CBS"), N,N- dicyclohexyl-2-benzothiazyl sulfenamide (abbreviated "DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide (abbreviated "TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide (abbreviated "TBSI"), tetrabenzylthiuram disulfide (abbreviated "TBZTD"), zinc dibenzyldithiocarbamate (abbreviated "ZBEC") and mixtures of these compounds.

Preferably, a primary accelerator of the sulfenamide type is used.

The final composition thus obtained can then be calendered, for example in the form of a sheet, a plate in particular for characterization in the laboratory, or even extruded in the form of a semi-finished (or profiled) rubber that can be used for example to form a rubber profile used for the manufacture of a waterproof inner layer.

The composition can be either in the green state (before crosslinking or vulcanization), or in the cured state (after crosslinking or vulcanization), can be a semi-finished product which can be used in a tire. The crosslinking of the composition can be carried out in a manner known to those skilled in the art, for example at a temperature of between 130° C. and 200° C., under pressure.

The inner waterproof layer can be used in any type of pneumatic object. By way of examples of such pneumatic objects, mention may be made of inflatable boats, balloons or balls used for games or sports.

Consequently, the invention also relates to a tire comprising an inner waterproof layer as defined above. The tire is in particular as described in FIG. 1. In general, the tire according to the invention is intended to be fitted to motor vehicles of the passenger car type, SUVs (“Sport Utility Vehicles”), two-wheelers (in particular motorcycles) , airplanes, agricultural tires, as well as industrial vehicles such as vans, trucks and other transport or handling vehicles. A subject of the invention is also the use of copper (II) gluconate, as defined above, in a rubber composition for tires for preventing or eradicating the proliferation of insects, more precisely of larvae, in particular of mosquito larvae, present in stagnant water in the tire, that is to say water in contact with the inner waterproof layer and retained by the sidewalls. The rubber composition is advantageously as described previously.

The literature indicates that a copper concentration of between 500 ppb and 80 ppm in water is able to block the growth of larvae, in particular mosquito larvae, and therefore to present a larvicidal character.

The copper (II) gluconate incorporated in a rubber composition is capable of releasing copper into water in contact with said composition. The concentration of copper (II) in the water is consistent with a mosquito larviciding effect. In fact, a tire comprising this type of composition as an inner waterproof layer and in particular dumped in the wild or reused for any other application different from its primary destination, can prevent the proliferation of mosquitoes by stagnation of rainwater inside. of the tire, and thus in contact with the inner waterproof layer. Furthermore, the introduction of this copper gluconate does not modify the process for manufacturing a rubber composition for tires. In particular, the rubber composition for the inner waterproof layer retains its ability to cure, that is to say its ability to be crosslinked or vulcanized, which makes it possible to envisage the manufacture of such compositions on usual industrial manufacturing tools. .

In addition, the introduction of this copper gluconate does not reduce the sealing properties of the inner sealing layer composition and the mechanical properties are satisfactory, which allows the properties of the tire to be maintained during its service. The invention as well as its advantages will be understood in greater depth, in the light of the examples of embodiment which follow.

EXAMPLE 1

In Table 1 below are grouped the formulations of inner waterproof layers used to illustrate the present invention. Composition C-0 contains no copper salt. It used for reference. Compositions C-1, C-2, C-3 and C-4 which comprise a copper (II) salt are presented for comparison and are not in accordance with the invention. Finally, composition C-5 comprises copper (II) gluconate and is in accordance with the invention.

The mixtures were made by means of an internal mixer using a conventional mode of introduction with initial incorporation of the elastomer, the carbon black, the additives except the zinc oxide introduced just before extracting and recovering the masterbatch at a maximum temperature of 110-115°C.

The copper, accelerator and sulfur salts are then incorporated on an external mixer (roller tool) at a temperature of 40°C. [Table 1]

(1) Brominated butyl elastomer

(2) Natural rubber

(3) Cabot Company N660

(4) TDAE Oil from Exxon Company (5) Copper(II) Sulfate, CuSC>4 CAS 7758-98-7 from Sigma-Aldrich Company

(6) Copper (II) 2-ethylhexanoate, CuEH CAS 149-11 -1 from Sigma-Aldrich

(7) Copper(II) Acetlylacetonate, CuAA CAS 13395-16-9 from Sigma-Aldrich Company

(8) Copper(II) 6-hydroxyquinoleate, CuHQ CAS 10380-28-6 from Sigma-Aldrich Company

(9) Copper (II) gluconate, CuG CAS 529-07-3 from Sigma-Aldrich (10) Cyclohexyl-benzothiazyl-sulfenamide from Solutia

Measurements and tests

A) Rheometry

The rheometry was carried out, according to the DIN53529-part 2 and 3 standard (June 1983) using an RPA 2000 oscillating chamber rheometer from the company Alpha Technologies. The temperature is constant (i.e. variation of less than 2°C) and set at 170°C. The monitoring of the rheometric torque (expressed in dN.m) over time is carried out in a measuring chamber oscillating at 1.67Hz and for a peak-peak deformation of 2.8%. To assess a possible disturbance or modification of the vulcanization process, the difference between the torque reached at optimum vulcanization (Cmax) and the torque at time t=0 (Cmin) for each composition is compared to that of the composition witness. For each composition, these values are reported in Table 2 below:

[Table 2] The difference in rheometric torque between the start and the optimum of vulcanization is the same for all the compositions compared to the control composition except for composition 4 where the Cmax obtained is significantly higher.

B) Tensile test These tensile tests make it possible to determine the elasticity stresses and the breaking properties. Unless otherwise indicated, they are carried out in accordance with the French standard NF IS037 of December 2005.

The stresses at break (in MPa) and the elongations at break (in %) are measured under normal conditions of temperature (23°C, plus or minus 2°C) and hygrometry (50%, plus or minus 10% relative humidity). A processing of the tensile recordings also makes it possible to plot the modulus curve as a function of the elongation.

The stress (MPa) and the elongation (%) at break of the various compositions are reported in Table 3 below, in base 100 with respect to the control composition.

[Table 3]

These measurements indicate stress and elongation at break values which are not significantly different from the composition (C-0) except for the compositions C-2 and C-5. However, for these two compositions, this slight decrease observed is acceptable and allows the use of these compositions as an inner waterproof layer.

C) Release of Copper(II) into Water To illustrate the invention, tests of the release of copper II into water in contact with the various compositions were carried out. The compositions were vulcanized in the form of thin plates 2.5 mm thick. Samples measuring 7×15 cm ² offering a total exchange surface of 210 cm ² were immersed in 450 ml of deionized water. The duration of immersion in deionized water is three weeks at room temperature. Due to the quantities of copper salts introduced, the concentration of Cu(II) in compositions C-1 to C-5 is the same and is equal to 1200 ppm. The quantity of copper ion which has passed into the water is then measured and expressed in ppm in water. This measurement is carried out using a conventional technique of elementary analysis with a flame emission spectrometer of the ICP-OES type (for Inductively Coupled Plasma Optical Emission Spectrometry). The results are grouped in Table 4 below:

[Table 4]

The deionized water used in this example contains a residual of 0.04 ppm of Cu(ll). It is rather surprisingly noted that despite a rather diversified panel of copper salts retained in this comparison, only copper gluconate leads to a more substantial release into the water (about 20 times more). The concentration reached is close to 1 ppm of copper. The literature indicates that a copper concentration of between 500ppb and 80ppm in water is able to block the growth of mosquito larvae and therefore present a larvicidal character.

EXAMPLE 2

In this second example, the aim is to determine the quantity of copper II released into the water as a function of the quantity of copper II gluconate initially introduced into a composition in accordance with the present invention. The release conditions are similar to Example 1 except for the soaking time which is reduced to 5 days. The compositions are prepared by following the same procedure as in Example 1. Composition C-0 is the same composition C-0 as in example 1. It is a control composition not comprising any copper salt. Compositions C-6 to C-9 are compositions according to the invention. The compositions considered with variable amounts of copper II gluconate are detailed in Table 5 below:

[Table 5]

(1) Brominated butyl elastomer

(2) Natural rubber

(3) Cabot Company N660

(4) TDAE Oil from Exxon Company (9) Copper(II) Gluconate, CuG CAS 529-07-3 from Sigma-Aldrich Company

(10) Cyclohexyl-benzothiazyl-sulfenamide from Solutia

C) Permeability

The permeability is measured by a device consisting of two chambers between which a mixture test piece is placed. A pressure difference is applied between the two chambers and the pressure increase in the lower pressure chamber is measured as a function of time. The temperature is set at 60°C (± 2°C). The specimen is in the form of a 60mm disk with a thickness of 2mm. The amount of gas that has passed through the specimen is proportional to the increase in pressure measured over time by means of a differential sensor. The permeability coefficient can then be determined by exploiting this pressure difference.

The tensile tests are carried out according to the protocol described in example 1.

Table 6 below groups together the properties at break (stress at break and elongation at break) as well as air permeability of compositions C-0, C-6 to C-9. the copper gluconate level does not significantly affect the mechanical properties. Moreover, the air permeability is not increased either, or even rather reduced, which is essential and beneficial to the composition of the inner waterproof layer in order to fully fulfill its sealing function within of the tire (permeability index greater than 100 = reduced air permeability = improved sealing).

[Table 6]

Table 7 below indicates the concentrations of copper II measured in the water having been used for soaking the samples of mixtures of the various compositions with more or less additives of copper II gluconate and this, after 5 days of soaking at room temperature. An increasing and monotonous change in the concentration of copper II released into the water is noted in proportion to the amount initially introduced into each of the compositions of the invention. [Table 7]

The deionized water used in this example contains a residual of 0.02 ppm Cu(ll). It can be deduced from this that, from 0.5 pce of copper II gluconate in the composition and from 5 days of soaking, the resulting concentration of copper II in the water is 0.1 ppm, and is thus greater than 500 ppb recommended for the effect on mosquito larvae.

Claims

1. Inner waterproof layer for tires having a rubber composition based on at least:

- 5 phr of one or more reinforcing fillers;

- from 0 to 40 phr of a plasticizer; characterized in that the rubber composition further comprises copper (II) gluconate.

2. Inner waterproof layer according to the preceding claim, characterized in that the rubber composition comprises at least 0.5 phr of copper (II) gluconate, preferably up to 15 phr of copper (II) gluconate, in particular from 0.5 to 15 phr of copper (II) gluconate, more preferably from 0.75 to 12 phr.

3. Inner waterproof layer according to any one of the preceding claims, characterized in that the butyl rubber or rubbers are chosen from isobutylene rubbers, copolymers of isobutylene and isoprene, bromobutyl rubbers such as the bromoiisobutylene-isoprene copolymer , chlorobutyl rubbers such as chloroisobutylene-isoprene copolymer, and copolymers of isobutylene and styrene derivatives such as copolymers of isobutylene and brominated methylstyrene.

4. Inner waterproof layer according to any one of the preceding claims, characterized in that the elastomeric matrix comprises 100 phr of one or more butyl rubbers.

5. Inner waterproof layer according to any one of claims 1 to 3, characterized in that the elastomeric matrix up to 50 phr of a diene elastomer other than butyl rubber.

6. Inner waterproof layer according to the preceding claim, characterized in that the diene elastomer other than butyl rubber is chosen from polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

7. Inner waterproof layer according to claim 5, characterized in that the diene elastomer other than butyl rubber is chosen from polybutadienes, synthetic polyisoprenes, natural rubber, butadiene-styrene copolymers, isoprene copolymers -butadiene, isoprene-styrene copolymers, isoprene-butadiene-styrene copolymers and mixtures of these elastomers.

8. Inner waterproof layer according to any one of the preceding claims, characterized in that the rubber composition comprises a reinforcing filler chosen from carbon black, a reinforcing inorganic filler such as silica or a mixture of these fillers.

9. Inner waterproof layer according to any one of the preceding claims, characterized in that the rubber composition comprises 10 to 100 phr of reinforcing filler.

10. Inner waterproof layer according to any one of the preceding claims, characterized in that the rubber composition comprises an additional filler chosen from the group consisting of semi-reinforcing fillers, inert fillers and mixtures of these fillers.

11. Inner waterproof layer according to any one of the preceding claims, characterized in that the additional filler chosen from the group consisting of graphite, kaolin, chalk, talc and their combinations.

12. Inner waterproof layer according to any one of the preceding claims, characterized in that the plasticizer is chosen from plasticizing oils, plasticizing resins or combinations thereof.

13. Inner waterproof layer according to any one of the preceding claims, characterized in that the rubber composition is based on a sulfur crosslinking system.

14. A tire comprising an inner sealed layer as defined according to any one of the preceding claims.

15. Use of copper (II) gluconate in a tire rubber composition for the prevention or eradication of the proliferation of insects, in particular mosquito larvae present in standing water in the tire.