Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L15/00—Compositions of rubber derivatives
  • C08L15/02—Rubber derivatives containing halogen
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0016—Compositions of the tread
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0025—Compositions of the sidewalls
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/0427—Coating with only one layer of a composition containing a polymer binder
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/01—Hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/07—Aldehydes; Ketones
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D111/00—Coating compositions based on homopolymers or copolymers of chloroprene
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D123/00—Coating compositions based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Coating compositions based on derivatives of such polymers
  • C09D123/26—Coating compositions based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Coating compositions based on derivatives of such polymers modified by chemical after-treatment
  • C09D123/32—Coating compositions based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Coating compositions based on derivatives of such polymers modified by chemical after-treatment by reaction with compounds containing phosphorus or sulfur
  • C09D123/34—Coating compositions based on homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Coating compositions based on derivatives of such polymers modified by chemical after-treatment by reaction with compounds containing phosphorus or sulfur by chlorosulfonation
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/20—Diluents or solvents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C2200/00—Tyres specially adapted for particular applications
  • B60C2200/02—Tyres specially adapted for particular applications for aircrafts
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2321/00—Characterised by the use of unspecified rubbers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2423/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
  • C08J2423/26—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers modified by chemical after-treatment
  • C08J2423/32—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers modified by chemical after-treatment by reaction with phosphorus- or sulfur-containing compounds
  • C08J2423/34—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers modified by chemical after-treatment by reaction with phosphorus- or sulfur-containing compounds by chlorosulfonation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2201/00—Properties
  • C08L2201/08—Stabilised against heat, light or radiation or oxydation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2201/00—Properties
  • C08L2201/56—Non-aqueous solutions or dispersions

Definitions

• the invention relates to an anti-ozone protection composition for a crosslinked rubber article, the composition being based on at least one chlorinated elastomer, at least one hydrocarbon solvent and at least one aprotic polar solvent.
• Crosslinked rubber articles such as for example pneumatic or non-pneumatic tires, are generally based on diene polymers comprising ethylenic double bonds in their main chain. These polymers are sensitive to the action of ozone due to the presence of these double bonds.
• compositions based on diene polymers commonly incorporate anti-ozone chemical compounds as well as waxes.
• Anti-ozone chemicals slow down the formation and propagation of cracks under static and dynamic conditions.
• Waxes provide additional static protection by forming a protective coating on the surface.
• anti-ozonating agents also called anti-zone agents
• waxes are not very compatible with certain uses of rubber articles, such as for example pneumatic tires especially intended for fitting onto airplanes.
• an airplane pneumatic tire must withstand pressure, load and high speed conditions, in particular on landing where they must go from zero speed to very high speed, causing considerable heating and wear.
• These particular wear conditions do not concern other types of tires such as tires for passenger vehicles, heavy goods vehicles, civil engineering or off-road vehicles.
• an airplane tire is subjected to strong stresses during the landing phases (“Touch Down”).
• Document EP0728810A1 discloses a coating consisting of an aqueous composition based on polymers chosen from the group of acrylic, methacrylic and vinyl esters, a constituent comprising a hydrophilic silica and a polymer whose monomer is chosen from acrylic, methacrylic and vinyl monomers. .
• this composition exhibits poor adhesion to a rubber surface, it must be deposited in several batches, with very thin layers each time. This restrictive application in several layers results in a coating thickness that is difficult to control and in non-homogeneous distributions of the coating.
• Another anti-ozone coating composition for pneumatic tires is also known from document WO2001 / 094453A1.
• This composition is based on polyurethane polymers.
• the disadvantage of this composition is a complicated implementation requiring a first step of functionalization of the rubbery support by a functionalization solution, followed by a drying step which can be more or less long, then only then the deposition of the composition. coating.
• the bond between the elastomer of the tire and the polyurethane is achieved by virtue of the polar functions of the functionalization solution. Its protection efficiency with respect to ozone is therefore dependent on the functionalization step of the support, since this step allows the adhesion of the polyurethane layer to its support.
• An aim of the present invention is to meet this need.
• an anti-ozone protection composition for a crosslinked rubber article in particular for a crosslinked pneumatic tire, in particular intended to equip airplanes, based on at least one chlorinated elastomer, at least one solvent. hydrocarbon and at least one polar aprotic solvent.
• This composition is particularly advantageous and easy to use. It is not necessary to functionalize the crosslinked rubber support, it is applied directly to the crosslinked support, in a single step, which has the advantage of being able to produce a layer of uniform thickness.
• This composition advantageously makes it possible to form a continuous, flexible coating which adheres to any surface of the pneumatic tire which, by its presence, opposes degradation due to ozone.
• the rubbery behavior of this composition makes it possible to advantageously resist all the deformations undergone by the crosslinked rubber article.
• this composition is advantageously used to protect pneumatic tires especially intended for fitting onto airplanes since it is resistant to the deformations undergone after the manufacture of the tires, in particular during the inflation and subsequent use of said tire. It also has the advantage of being able to be applied to any crosslinked rubber surface, and in particular to new or retreaded pneumatic tires.
• Another object of the present invention relates to a crosslinked elastomeric article having at least one elastomeric surface in contact with air, said elastomeric surface being wholly or in part coated with an anti-ozone protective composition as defined above.
• the crosslinked elastomeric article is chosen from pneumatic tires, non-pneumatic tires, conveyors, gaskets, shoe soles, tracks, hoses, hoses, windshield wipers, ping-pong rackets. and floor coverings. More advantageously still, the crosslinked elastomeric article is a pneumatic or non-pneumatic crosslinked tire of which at least one outer layer is at least partly coated with an anti-ozone protection composition as defined above.
• Figure 1 photograph of a groove in a tread of an airplane tire comprising areas protected by the protective composition according to the invention and areas not protected by the protective composition of the invention.
• Line A-A and line B-B delimit the areas which have or have not been protected by the protective composition of the invention.
• the zone delimited in a rectangle by the lines A-A and B-B has not been the subject of an application of the protective composition according to the invention. Large cracks are visible inside this rectangle.
• the protected areas that is to say between the top of the photo and the line A-A and between the line B-B and the bottom of the photo, there are no cracks.
• Figure 2 photograph of a groove in a tread of an airplane pneumatic tire; groove in which the protective composition according to the invention has been applied. No cracks are visible.
• Figure 3 photograph of two grooves in a tread of an airplane pneumatic tire; grooves in which no protective composition according to the invention has been applied. Numerous cracks are visible in the bottom of these furrows.
• a first subject of the invention relates to an anti-ozone protective composition for a crosslinked rubber article, in particular for a crosslinked pneumatic tire, in particular intended to be fitted to airplanes, the composition being based on at least one chlorinated elastomer, at least one hydrocarbon solvent and at least one polar aprotic solvent.
• rubber article or “elastomeric article” is meant an article comprising one or more elastomers, in particular one or more diene elastomers.
• This rubber article comprises at least one rubber surface (also referred to as an elastomeric surface) in contact with air.
• crosslinked rubber article means a rubber article which has undergone a crosslinking step, that is to say that the rubber or the elastomers forming this article are in the form of a network. obtained by establishing bridges between the macromolecular chains of the rubber or of said elastomers. The formation of bridges can take place by any known crosslinking agent, such as for example peroxides or else by sulfur. When the crosslinking agent is sulfur, this is referred to as vulcanization.
• diene elastomer or rubber indiscriminately
• elastomer or rubber indiscriminately
• an elastomer consisting at least in part ie, a homopolymer or a copolymer
• diene monomer units monomers carrying two carbon-carbon double bonds, conjugated or not.
• diene elastomers can be classified into two categories: “essentially unsaturated” or “essentially saturated”.
• essentially unsaturated is understood to mean in general a diene elastomer derived at least in part from conjugated diene monomers, having a level of units or units of diene origin (conjugated dienes) which is greater than 15% (% by moles); it is thus that diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins of the EPDM type do not fall within the preceding definition and can in particular be qualified as “essentially saturated” diene elastomers (level of diene. units of weak or very weak diene origin, always less than 15 mol%).
• diene elastomer capable of being used in the elastomeric articles in accordance with the invention is particularly understood: any homopolymer of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms; any copolymer of a diene, conjugated or not, having from 4 to 18 carbon atoms and at least one other monomer.
• composition based on is meant 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 each other, less partially, during the various phases of manufacture of the composition and / or during the use of this composition.
• the expression “part by weight per hundred parts by weight of elastomer” should be understood to mean the part, by mass per hundred parts by mass of elastomer.
• any interval of values designated by the expression “between a and b” represents the domain of values going from more than a to less than b (that is to say limits a and b excluded) while any range of values designated by the expression “from a to b” signifies the range of values going from a to b (that is to say including the strict limits a and b).
• a “predominant” compound it is understood, within the meaning of the present invention, that this compound is predominant among the compounds of the same type in the composition, that is to say that it is the one which represents the greatest amount by mass among compounds of the same type.
• a major elastomer is the elastomer representing the greatest mass relative to the total mass of the elastomers in the composition.
• a so-called majority filler is that representing the greatest mass among the fillers of the composition.
• the majority elastomer represents more than half of the mass of the elastomers.
• the compounds mentioned in the description which include carbon can be of fossil origin or biobased. In the latter case, they may be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. This concerns in particular polymers, solvents and additives.
• the anti-ozone protection composition of the invention comprises at least one chlorinated elastomer.
• chlorinated elastomer is understood to mean a polymer which comprises one or more chlorine atoms and which is flexible, deformable, exhibiting elasticity of the rubber type according to the IUPAC definition of elastomers.
• the chlorine content of the chlorinated elastomer is within a range ranging from 20% to 50% by weight relative to the total weight of the elastomer, more preferably in a range ranging from 25% to 45%, more preferably still ranging from 30% to 37% by weight per relative to the total weight of the elastomer.
• the level of chlorine in the elastomer is measured according to the usual analysis techniques for elastomers.
• the chlorinated elastomer has a Mooney ML viscosity index (l + 4) at 100 ° C. within a range ranging from 20 to 100 MU, more preferably ranging from 25 to 60 MU.
• chlorinated elastomers examples include polychloroprene, chlorosulphonated polyethylene and mixtures of these elastomers.
• chlorinated elastomers are available from suppliers such as Du Pont de Nemours, Lianda, etc.
• the chlorinated elastomer is a chlorosulfonated polyethylene, in particular having a sulfur content in a range ranging from 0.8% to 2% by weight relative to the total weight of the polyethylene, more particularly in a range ranging from 0, 9% to 1.5% more preferably ranging from 1% to 1.5% by weight.
• the sulfur content in the elastomer is measured according to the usual analysis techniques for polymers.
• Chlorosulfonated polyethylenes are made by simultaneous functionalization and modification of polyethylene from chlorine and sulfur dioxide. They are marketed under the name CSM.
• Particular embodiments of the present invention may comprise at least one chlorosulfonated polyethylene having a chlorine content ranging from 20% to 50% by weight and a sulfur content ranging from 0.8% to 2% by weight, more preferably can comprise at least one chlorosulfonated polyethylene having a chlorine content in a range ranging from 25% to 45% by weight and a sulfur content in a range ranging from 0.9% to 1, 5%, more preferably still, can comprise at least one chlorosulfonated polyethylene having a chlorine content within a range ranging from 30% to 37% and a sulfur content ranging from a range ranging from 0.8% to 1.2%.
• the chlorine content and that of sulfur in the elastomer are expressed in% by weight relative to the total weight of the chlorosulfonated polyethylene.
• the content of the chlorinated elastomer, preferably of polychloroprene and / or of chlorosulfonated polyethylene, in the composition is within a range ranging from 3% to 25% by weight relative to the total weight of the composition, more preferably in a range ranging from 5% to 20% by weight relative to the total weight of the composition.
• the concentration is too low to obtain the desired effects and above 25% by weight the composition becomes very viscous and difficult to apply.
• chlorinated elastomer concentration depends on the need or not, for the elastomeric surface to be protected, of a significant final thickness of protection and on the conditions of use of this surface. If the rubber article is used in an atmosphere with high ozone concentrations, then the highest chlorinated elastomer concentration will preferably be chosen to reduce the number of layers to be applied and to obtain the best protection.
• the anti-ozone protection composition according to the invention comprises at least one hydrocarbon solvent.
• hydrocarbon solvent is meant a solvent mainly containing carbon atoms and hydrogen atoms.
• the hydrocarbon solvent is liquid at ambient temperature (20 ° C.) and at atmospheric pressure.
• the hydrocarbon solvent is a solvent for aliphatic hydrocarbons. It can have a distillation range within a range from 50 ° C to 220 ° C.
• the hydrocarbon solvent which can be used in the context of the invention is a solvent for C4-C14 aliphatic hydrocarbons, preferably C5-C10, more preferably still C7-C9.
• the hydrocarbon solvent is preferably volatile at room temperature (20 ° C) and has a non-zero vapor pressure at room temperature (20 ° C) and atmospheric pressure, and in particular a vapor pressure ranging from 0.13 Pa to 40,000 Pa , in particular ranging from 1.3 Pa to 13000 Pa, and more particularly ranging from 1.3 Pa to 1300 Pa.
• the anti-ozone protection composition according to the invention also comprises at least one aprotic polar solvent.
• aprotic polar solvent means a solvent having a dipole moment without an acidic hydrogen atom, that is to say bonded to a heteroatom.
• the heteroatom is an oxygen atom.
• the aprotic polar solvent is chosen from ketone solvents, ester solvents and mixtures of these solvents.
• the aprotic polar solvent is chosen from dimethylformamide (DMF); acetone, methyl ethyl ketone (also known as butanone), methyl propyl ketone (also known as pentanone-2), methyl isopropyl ketone (also known as 3-methyl-2 -butanone), methyl isobutyl ketone (also known as 4-methyl-2-pentanone), cyclic ketones such as cyclohexanone; tetrahydrofuran (THF); acetonitrile; dimethyl sulfoxide (DMSO) and mixtures thereof.
• DMF dimethylformamide
• acetone methyl ethyl ketone
• methyl propyl ketone also known as pentanone-2
• methyl isopropyl ketone also known as 3-methyl-2 -butanone
• methyl isobutyl ketone also known as 4-methyl-2-pentanone
• cyclic ketones such as cyclo
• the aprotic polar solvent is chosen from acetone, butanone, pentanone-2, 3-methyl-2-butanone, 4-methyl-2-pentanone and their mixture.
• the aprotic polar solvent is acetone.
• the polar aprotic solvent preferably the ketone solvents and the ester solvents, are miscible in the hydrocarbon solvent, in particular in the aliphatic hydrocarbon solvent.
• the polar aprotic solvent forms a homogeneous and stable mixture (to the naked eye) when it is placed in the presence of said hydrocarbon solvent.
• the hydrocarbon solvent is the majority solvent. According to this embodiment; the hydrocarbon solvent is that which represents the largest quantity by mass among the solvents of the composition.
• the mass ratio of aprotic polar solvent relative to the hydrocarbon solvent is within a range ranging from 15:85 to 85:15 per 100% by mass of solvent, preferably from 30:70 to 70:30. for 100% by mass of solvent, more preferably from 40:60 to 60:40 for 100% by mass of solvent.
• the hydrocarbon solvent is a solvent for C4-C14 aliphatic hydrocarbons, preferably C5-C10, more preferably still C7-C9 and the aprotic polar solvent is chosen from acetone , butanone, pentanone-2, methyl-3-butanone, methyl-4-pentanone-2 and a mixture thereof.
• the hydrocarbon solvent is a solvent for C5-C10 aliphatic hydrocarbons, more preferably still C7-C9 and the aprotic polar solvent is chosen from butanone, methyl-3-butanone and their mixture.
• the anti-ozone protection composition according to the invention may also comprise all or part of the usual additives and processing agents, known to those skilled in the art and usually used in rubber compositions for pneumatic tires, such as by example of plasticizers (such as plasticizing oils and / or plasticizing resins), reinforcing or non-reinforcing fillers, pigments, anti-oxidants, anti-fatigue agents, etc.
• plasticizers such as plasticizing oils and / or plasticizing resins
• reinforcing or non-reinforcing fillers pigments, anti-oxidants, anti-fatigue agents, etc.
• the process for obtaining the anti-ozone protection composition is simple.
• the constituents are brought into contact with each other; they are mixed until a homogeneous solution is obtained, that is to say a solution in which there are no particles in suspension visible to the naked eye.
• the order in which the constituents of the protective composition are used is irrelevant.
• Another possibility of manufacturing the composition according to the invention is to bring the two solvents into contact together and then to add the chlorinated elastomer.
• the solution can be applied to any crosslinked rubber article or crosslinked elastomeric support.
• This composition can thus be deposited at room temperature (20 ° C.) by any known means and in particular with a brush, a roller or by spraying with a gun.
• the layer obtained after application is then allowed to dry; the two solvents evaporate, the elastomer thus deposited forms the protective coating.
• the drying time is in particular of the order of 5 min to 10 min, a time which can be further reduced by operating heating, for example by circulating hot air or by radial heating, which respects maintenance of the surface temperature of the rubber article to be protected below 60 ° C.
• the dry coating obtained exhibits high mechanical strength, which allows it to remain in place when the tires are stored until they are put into service.
• the desired thickness of the dry coating will vary depending on the elastomeric surface where the anti-ozone protection composition is applied. Good results are obtained, for example, with dry coatings having a thickness greater than or equal to 5 ⁇ m.
• a thickness within a range ranging from 5 ⁇ m to 500 ⁇ m will be preferred.
• a thickness within a range ranging from 5 ⁇ m to 50 ⁇ m will be sufficient.
• the protective coating cannot be as effective on the parts of the tire in permanent contact with the ground.
• the anti-ozone protection composition is deposited on the entire surface of the tread, the resulting dry coating makes it possible to protect the tread before its use and continues its action on the parts which are not in contact. contact with the ground therefore in particular the hollow bottoms (grooves) of the sculptures, the coating part covering the tops of the sculptures directly in contact with the ground being rapidly destroyed since it is subject to wear.
• the anti-ozone protection composition according to the invention can be applied to any type of crosslinked rubber article, preferably to a crosslinked pneumatic tire in particular intended to be fitted on airplanes.
• Another object of the present invention relates to a crosslinked elastomeric article comprising at least one elastomeric surface in contact with air, said elastomeric surface being all or in part coated with an anti-ozone protective composition defined above.
• elastomeric surface is understood to mean a surface of an article, this surface being based on at least one elastomer, preferably diene elastomer as defined above and another component.
• the elastomeric article can be any known elastomeric article, and preferably chosen from pneumatic tires, in particular those intended to equip airplanes, non-pneumatic tires, conveyors, gaskets, shoe soles, tracks, pipes. , hoses, windshield wipers, table tennis rackets and floor coverings.
• a non-pneumatic tire is meant a tire intended to form a cavity by cooperating with a support element, for example a rim, this cavity being able to be pressurized at a pressure greater than atmospheric pressure.
• a non-pneumatic tire is not suitable for being pressurized.
• a non-pneumatic tire is a toric body formed by at least one polymeric material, intended to perform the function of a tire but without being subjected to inflation pressure.
• a non-pneumatic tire can be solid or hollow.
• a hollow non-pneumatic tire can contain air, but at atmospheric pressure, that is to say it has no pneumatic rigidity provided by an inflation gas at a pressure greater than atmospheric pressure.
• the pneumatic tires according to the invention are intended to equip vehicles of any type such as passenger vehicles, two-wheeled vehicles, heavy goods vehicles, agricultural vehicles, civil engineering vehicles or airplanes or, more generally. , on any rolling device.
• Non-pneumatic tires are intended to be fitted on passenger vehicles or two-wheelers.
• the pneumatic tires according to the invention are intended to equip airplanes.
• the crosslinked elastomeric article is a pneumatic crosslinked tire, preferably intended to equip an aircraft, or a non-pneumatic tire, at least one outer layer of which has an elastomeric surface at least partly coated with an anti-ozone protective composition.
• the term “outer layer” is understood to mean an elastomeric layer which is in contact with air (other than the inflation gas in the context of a pneumatic tire); as opposed to the inner layers which are elastomeric layers in contact with each other or in contact with the inflation gas.
• the outer layer may be the tread of the pneumatic or non-pneumatic tire, the layer forming the sidewalls of the pneumatic tire or the spokes in the context of a non-pneumatic tire.
• the crosslinked elastomeric article is a pneumatic crosslinked tire, in particular intended to equip airplanes comprising a tread and sidewalls, said tread and / or said sidewalls being at least partly coated with a composition of anti-ozone protection defined above. More preferably, this tread can be retreaded.
• compositions C1 to C4 are prepared:
• the tread of this retreaded tire is conventionally produced from a composition based on natural rubber and carbon black.
• the sculpture of this tread comprises 4 grooves. On each groove, 5 zones of identical length are materialized and the compositions C1 to C4 are applied using a brush in the manner below on the 2 nd and the 4 th groove. The ier the grooves and furrows 3 rd do not include treatment.
• the first groove is the one located closest to the wheel brake disc, in the direction of rotation of the tire, and the 4 th groove is the one that is to farthest from the wheel of the brake disc. After drying at a temperature of 23 ° C., the thickness of the coating is between 0.05 and 0.10 mm.
• composition C2 composition C2
• the tire is then mounted on a rim and is inflated to a pressure of 14.2 bar. Static ozone test
• the tire is taken out of the chamber for the evaluation of the number of cracks in the tread groove, then replaced for another 2 weeks in the same thermostatically controlled chamber, the ozone concentration of which is increased to 0.4 ppm. After 4 weeks, the tire is taken out of the chamber to assess the number of cracks in the tread grooves.
• zone A not comprising any protective composition and which corresponds to a control outside the invention, is completely cracked from the first week of storage in contact with ozone.
• the action of ozone is therefore particularly effective on this zone A of the tread.
• compositions C3 and C4 have the advantage of being more protective than compositions C1 and C2 which already have excellent protection against a high ozone concentration (0.4 ppm corresponds to 6 times the average of the ozone concentration. in the troposphere).
• the protective compositions in accordance with the invention therefore provide very good anti-ozone protection for atmospheres in which the ozone concentrations are very high.

Applications Claiming Priority (2)

Publications (1)

Family

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• 2020
  • 2020-05-29 FR FR2005702A patent/FR3110911B1/fr active Active
• 2021
  • 2021-05-26 WO PCT/FR2021/050949 patent/WO2021240109A1/fr unknown
  • 2021-05-26 EP EP21734197.3A patent/EP4157948A1/de active Pending
  • 2021-05-26 US US17/928,449 patent/US20230212375A1/en active Pending

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