Method for assembling rubber components.

Abstract

The invention relates to a method for assembling two rubber components comprising the following steps of: a) coating a surface of a first rubber component with an aliphatic solvent, which aliphatic solvent is selected from the group consisting of linear, branched or cyclic C16-C20 chain hydrocarbon compounds, distillation fractions (cuts) comprising said hydrocarbon compounds, and mixtures of said hydrocarbon compounds, b) affixing a second rubber component to the coated surface of the first rubber component.

Description

Title of the invention: Method for assembling rubber components. technical field

[0001] The invention relates to a method for assembling rubber components, in particular for the manufacture of tires. Previous technique

[0002] Rubber articles comprising a plurality of raw or (semi-)crosslinked rubber layers or components are manufactured by assembling and holding a plurality of rubber layers or components during the manufacturing and curing process. Known examples of such rubber articles are tires.

[0003] Some methods of assembling rubber components include mechanical methods such as sewing using adhesives, however mechanical methods can prove costly and in some cases ineffective.

[0004] As an alternative to mechanical methods, the assembly of rubber components can be done using solvents which are used to temporarily increase the inherent adhesion of rubber, enough to assemble the rubber components during the manufacture and curing of the rubber article.

[0005] In tire manufacturing, in particular, it is necessary to be able to apply the different layers or rubber components of a tire one on top of the other and for these layers to adhere to each other, both before and during the tire curing process, which bonds the layers together through cross-linking. The ability of the rubber components or layers to be tacky before curing is an essential property for tire manufacturing. This tackiness of the composition before curing is also called "raw tack," "tack," or "green tack."

[0006] In the field of tires for motor vehicles, the Applicant has in the past developed tire rubber compositions including, for example, a specific hydrocarbon resin giving the compositions very good raw stickiness, as described in document EP 3 237 523 Bl.

[0007] As mentioned above, this raw tackiness property of the rubber composition can also be obtained through the use of solvents, which proves to be an effective and relatively inexpensive technique. However, the solvents commonly used for this purpose are generally highly volatile organic compounds of fossil origin, such as toluene and hexane, which constitutes a real constraint with regard to protecting the health of staff in manufacturing workshops and respecting the environment.

[0008] Thus, an objective of the present invention is a method for assembling rubber components, particularly in the manufacture of tires, which is respectful of human health and the environment and relatively inexpensive, without emission of volatile organic compounds (VOCs). Detailed description of the invention

[0009] This objective is achieved in that the Inventors have discovered that a specific aliphatic solvent comprising hydrocarbon compounds with Ci6-C2o chains, when used in the process of assembling rubber components, makes it possible to improve or obtain a high level of stickiness at the interface of adjacent rubber components (raw or semi-crosslinked), for example adjacent layers present in a tire, and thus good fixation of the components to each other during the manufacturing process, while being free of VOCs, i.e. a “zero VOC” solvent.

[0010] Thus, a first object of the invention is a method for assembling two rubber components comprising the following steps: a. coat a surface of a first rubber component with an aliphatic solvent, which aliphatic solvent is chosen from the group consisting of hydrocarbon compounds with linear, branched or cyclic Ci6-C2o chains, distillation fractions (cuts) comprising said hydrocarbon compounds, and mixtures of said hydrocarbon compounds, b. affix a second rubber component to the surface coated with the first rubber component.

[0011] The invention, described in more detail below, relates to at least one of the embodiments listed in the following points:

[0012] 1. A method for assembling two rubber components comprising the steps the following, consisting of:

[0013] a) coat a surface of a first rubber component with an aliphatic solvent, which aliphatic solvent is chosen from the group consisting of hydrocarbon compounds with linear, branched or cyclic Ci6-C2o chains, distillation fractions (cuts) comprising said hydrocarbon compounds, and mixtures of said hydrocarbon compounds,

[0014] b) affix a second rubber component to the coated surface of the first rubber component.

[0015] 2. A method according to embodiment 1, wherein the aliphatic solvent has a flash point ranging from 107 to 160 °C, preferably from 110 to 160 °C, the flash point being measured according to ASTM D93.

[0016] 3. A method according to any one of embodiments 1 to 2, wherein the aliphatic solvent is chosen from distillation cuts with boiling points ranging from 244°C to 269°C, distillation cuts with boiling points ranging from 265°C to 310°C and distillation cuts with boiling points ranging from 290°C to 320°C, the boiling point being measured according to ASTM D86.

[0017] 4. A method according to any one of embodiments 1 to 3, wherein the aliphatic solvent is chosen from distillation cuts with boiling points ranging from 265°C to 310°C and distillation cuts with boiling points ranging from 290°C to 320°C, the boiling point being measured according to ASTM D86.

[0018] 5. A method according to any one of the preceding embodiments in which the solvent aliphatic is a cut of iso-alkanes, preferably obtained from raw materials of plant origin.

[0019] 6. A method according to any one of the preceding embodiments, in which the solvent aliphatic is applied to the surface of the first rubber component at a concentration less than or equal to 10 mg / cm2, preferably less than or equal to 5 mg / cm2.

[0020] 7. A method according to any one of the preceding embodiments, in which the the first rubber component and the second rubber component are independently of each other non-crosslinked or crosslinked.

[0021] 8. A method according to any one of the preceding embodiments, in which at least one of the first rubber component and the second rubber component is non-crosslinked.

[0022] 9. A method according to any one of the preceding embodiments, in which the The first rubber component and the second rubber component are non-crosslinked.

[0023] 10. A method according to any one of the preceding embodiments, in which the first rubber component and the second rubber component comprise, independently of each other, one or more elastomers selected from polychloroprene, butyl rubbers, natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (PB), nitrile rubbers (NBR), poly(isoprene-styrene), poly(isoprene-butadiene), poly(styrene-butadiene) (SBR), isoprene, styrene and butadiene terpolymers, ethylenic polymers, poly(ethylene-butadiene) (EBR) and mixtures thereof.

[0024] 11. A method according to any one of the preceding embodiments, in which the first rubber component and the second rubber component comprise, independently of each other, one or more elastomers selected from butyl rubbers, natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (PB), poly(isoprene-styrene), poly(isoprene-butadiene), poly(styrene-butadiene) (SBR), poly(ethylene-butadiene) (EBR), isoprene, styrene and butadiene terpolymers, and mixtures thereof.

[0025] 12. A method according to any one of the preceding embodiments, in which the less one of the first rubber component and of the second rubber component comprise, independently of each other, a diene elastomer, preferably highly unsaturated.

[0026] 13. A method according to any one of the preceding embodiments, in which The first rubber component and the second rubber component further comprise, independently of each other, at least one component selected from reinforcing fillers selected from carbon blacks and other reinforcing fillers, organic and inorganic of siliceous type in particular silica, as well as mixtures of these fillers, elastomer / filler coupling agents, non-reinforcing fillers, processing agents, stabilizers, plasticizers, pigments, antioxidants, anti-fatigue agents, anti-ozonating waxes, adhesion promoters, reinforcing resins, crosslinking systems based on sulfur and / or peroxide and / or bismaleimides, crosslinking activators including zinc monoxide and stearic acid, guanidic derivatives, extending oils, silica coating agents.

[0027] 14. A method according to any one of the preceding embodiments, wherein step a) and step b) are conducted at a temperature ranging from 15 to 100 °C.

[0028] 15. A method according to any one of the preceding embodiments, comprising in in addition to a step c) which follows step b) consisting of crosslinking the first and second assembled rubber components, by bringing the assembled rubber components to a temperature of 100 to 200°C.

[0029] 16. A method according to any one of embodiments 1 to 15 in which the two Rubber components constitute semi-finished products for tires. Definitions

[0030] In this document, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0031] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain inside the limits a and b (i.e., limits a and b excluded), while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​from a to b (i.e. including the strict bounds a and b).

[0032] In this description, "parts per percent of elastomer" or "pce" means the mass fraction of a constituent per 100 parts per mass of the elastomer(s), that is, of the total mass of the elastomer(s), whether thermoplastic or non-thermoplastic, in the composition. Thus, a constituent at 60 pce will mean, for example, 60 g of that constituent per 100 g of elastomer.

[0033] By solvent or compound “0 (zero) VOC” is meant an “organic compound having a vapor pressure of less than 0.01 kPa, at a temperature of 293.15 K (20°C) (according to European regulations - Directive 1999 / 13 / EC).

[0034] By rubber component is meant a rubber composition comprising at least a diene elastomer (or rubber), a reinforcing filler and a crosslinking system.

[0035] The carbon-containing compounds mentioned in the description may be of fossil origin or bio-based. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. Similarly, the compounds mentioned may also come from the recycling of previously used materials; that is, they may be partially or totally derived from a recycling process, or obtained from raw materials themselves derived from a recycling process. This includes, in particular, aliphatic solvents, monomers, and polymers, etc. Detailed description of the invention 1) Dienic elastomer

[0036] The rubber components may contain a single diene elastomer or several diene elastomers.

[0037] By elastomer (or "rubber", the two terms being considered synonymous) of the "diene" type, it is recalled here that it is to be understood in a known way as an (we mean one or more) elastomer derived at least in part (i.e., a homopolymer or a copolymer) from diene monomers (monomers bearing two carbon-carbon double bonds, conjugated or not).

[0038] Diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". Generally, "essentially unsaturated" means a diene elastomer derived at least in part from conjugated diene monomers, having a proportion of diene motifs or units (conjugated dienes) greater than 15% (mole percent); this is the case for diene elastomers such as butyl rubbers or diene copolymers and EPDM-type alpha-olefins do not fall under the previous definition and can be specifically described as "essentially saturated" diene elastomers (low or very low content of diene-derived motifs, always less than 15%). Within the category of "essentially unsaturated" diene elastomers, a "highly unsaturated" diene elastomer is defined as one with a content of diene-derived motifs (conjugated dienes) greater than 50%.

[0039] Having given these definitions, the term diene elastomer suitable for use in rubber components according to the invention is understood more specifically as:

[0040] (a) any homopolymer obtained by polymerization of a conjugated diene monomer having 4 to 12 carbon atoms;

[0041] (b) any copolymer obtained by copolymerization of one or more conjugated dienes between themselves or with one or more aromatic vinyl compounds having 8 to 20 carbon atoms;

[0042] (c) a ternary copolymer obtained by copolymerization of ethylene, an α-olefin having 3 to 6 carbon atoms with an unconjugated diene monomer having 6 to 12 carbon atoms, for example elastomers obtained from ethylene, propylene with an unconjugated diene monomer of the aforementioned type such as in particular hexadiene-1,4, ethylidene norbomene, dicyclopentadiene;

[0043] (d) a copolymer of isobutene and isoprene (butyl rubber), as well as the halogenated versions, particularly chlorinated or brominated, of this type of copolymer.

[0044] Although it applies to any type of diene elastomer, those skilled in the art of tires will understand that the present invention is preferably implemented with essentially (or strongly) unsaturated diene elastomers, in particular of type (a) or (b) above.

[0045] Suitable conjugated dienes include, in particular, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(alkyl in Ci-C5)-1,3-butadiene such as, for example, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, aryl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene. Examples of suitable vinylaromatic compounds include styrene, ortho-, meta-, para-methylstyrene, the commercial "vinyl-toluene" mixture, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, and vinylnaphthalene.

[0046] The copolymers may contain between 99% and 20% by mass of diene units and between 1% and 80% by weight of vinylaromatic units. The elastomers may have any microstructure that depends on the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the quantities of modifying and / or randomizing agent used. The elastomers may They can be, for example, block, statistical, sequenced, or microsequenced, and prepared in dispersion or solution; they can be coupled and / or star-shaped or functionalized with a coupling and / or star-shaping or functionalizing agent. Here, "functional" preferably refers to a chemical group that interacts with the reinforcing charge of the composition.

[0047] In summary, the diene elastomer of the composition is preferably chosen from the group of highly unsaturated diene elastomers consisting of polybutadienes (abbreviated "BR"), synthetic polyisoprenes (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers. Such copolymers are more preferably chosen from the group consisting of butadiene-styrene copolymers (SBR).

[0048] According to a preferred embodiment of the invention, the first rubber component and the second rubber component as used in the assembly process of the invention comprise, independently of each other, one or more elastomers selected from polychloroprene, butyl rubbers, natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (PB), nitrile rubbers (NBR), poly(isoprene-styrene), poly(isoprene-butadiene), poly(styrene-butadiene) (SBR), isoprene, styrene and butadiene terpolymers, ethylenic polymers, poly(ethylene-butadiene) (EBR) and mixtures thereof.

[0049] According to a preferred embodiment of the invention, the first rubber component and the second rubber component as used in the assembly process of the invention comprise, independently of each other, one or more elastomers selected from butyl rubbers, natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (PB), poly(isoprene-styrene), poly(isoprene-butadiene), poly(styrene-butadiene) (SBR), isoprene, styrene and butadiene terpolymers, and mixtures thereof.

[0050] According to another preferred embodiment of the invention, at least one of the first rubber component and the second rubber component to be assembled comprises, independently of each other, a diene elastomer, preferably highly unsaturated.

[0051] Thus, the invention preferably relates to rubber components in which said diene elastomer is selected from the group consisting of essentially unsaturated diene elastomers, and in particular from the group consisting of polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers, and mixtures of these elastomers. Preferably, the major diene elastomer is selected from the group consisting of polybutadienes, butadiene-styrene copolymers, and natural rubber.

[0052] According to one embodiment of the invention, the first rubber component and the second rubber component are independently of each other non-crosslinked (raw) or crosslinked (baked).

[0053] According to a more preferred embodiment of the invention, at least one of the first rubber component and the second rubber component is non-crosslinked (raw).

[0054] According to a more preferred embodiment, the first rubber component and the second rubber component are non-crosslinked.

[0055] According to one embodiment of the invention, the two rubber components constitute semi-finished articles for pneumatics. 2) aliphatic solvent

[0056] As mentioned above, a solvent is used to coat the surface of a rubber component in order to restore or "refresh" the stickiness of said component. Applying the solvent to the surface of the rubber component increases its stickiness, particularly its raw stickiness.

[0057] Generally, immediately after its manufacture, a raw rubber component (layer) has a still-warm surface that retains significant raw tackiness. However, after cooling or storage, external elements such as dust, oil, soap, and dirt, etc., settle on the surface, or elements of the rubber composition such as wax, sulfur, treatment agents, or antioxidants can migrate to the surface, so that the rubber component eventually loses its raw tackiness or its adhesive capacity. A solvent is therefore applied to the surface of the uncrosslinked rubber component to improve its raw tackiness.

[0058] Such a solvent differs from an adhesive in that it swells the surface of the rubber, and, in the present case, migrates within the rubber component before or after baking the assembly of rubber components.

[0059] In an embodiment where the rubber article is a tire, the assembled rubber components can be placed on a rotating drum in the manufacturing process and the rotational action helps the elution and migration of the solvent within the rubber component.

[0060] According to the present invention, the aliphatic solvent used in step a) of the assembly process is chosen from the group consisting of hydrocarbon compounds with linear, branched or cyclic Ci6-C2o chains, distillation fractions (cuts) comprising said hydrocarbon compounds, and mixtures of said hydrocarbon compounds.

[0061] Preferably, the aliphatic solvent according to the invention is a bio-based isoalkane fraction. "Bio-based" means that a product is partially or totally bio-based. As is known, a bio-based product is distinguished from a fossil-based product by its carbon-14 content.

[0062] According to one embodiment of the invention, the aliphatic solvent used in step a) of the process according to the invention is a cut of isoalkanes (iso-paraffins), preferably obtained from raw materials of vegetable origin.

[0063] The iso-alkane according to the invention is a Ci6-C2o isoalkane, by way of example, it may be a Ci6-Ci7 isoalkane, a Ci7-Ci8 isoalkane, a Ci8-C20 isoalkane and mixtures thereof.

[0064] According to one embodiment of the invention, the aliphatic solvent has a flash point ranging from 107 to 160°C, the flash point being measured according to ASTM D93. Advantageously, the aliphatic solvent has a flash point ranging from 110 to 160°C.

[0065] According to a preferred embodiment, the aliphatic solvent used in step a) of the assembly process is selected from distillation cuts with boiling points ranging from 244°C to 269°C, distillation cuts with boiling points ranging from 265°C to 310°C and distillation cuts with boiling points ranging from 290°C to 320°C, the boiling point being measured according to ASTM D86.

[0066] Advantageously, the aliphatic solvent used in step a) of the assembly process is chosen from distillation cuts with boiling points ranging from 265°C to 310°C and distillation cuts with boiling points ranging from 290°C to 320°C.

[0067] Examples of iso-alkane solvents that can be used in the present invention are iso-alkanes, for example, a mixture of iso-paraffins from the Isane Biolife® range marketed by Total Energies, in particular the iso-alkanes named "Isane 250", "Isane 270" and "Isane 290".

[0068] The application of the aliphatic solvent according to the invention can be carried out at concentrations that are generally used by those skilled in the art. According to one embodiment, the aliphatic solvent of the process of the invention is used to coat the surface of the first rubber component at a concentration less than or equal to 10 mg / cm2, (that is to say that for each cm2 of surface to be coated of the first rubber component, an amount less than or equal to 10 mg of solvent is applied), preferably less than or equal to 5 mg / cm2.

[0069] Generally speaking, any coating process known to those skilled in the art can be used to coat the surface of the first rubber component with the solvent aliphatic, examples of such a coating process include spray application, roller application, drip application, etc.

[0070] During the coating process, the solvent is left for a certain time T necessary to allow the excess solvent to migrate into the rubber component and create the adhesive interface. Those skilled in the art will be able to determine this time T required for the proper application of the coating. For example, the time T may vary from a few seconds to a few minutes. Preferably, the time T is less than 30 minutes.

[0071] In a particular embodiment of the present invention, step a) of the assembly process can be repeated one or more times, preferably once, before proceeding to step b).

[0072] Step a) and step b) of the process according to the invention can be carried out at operating temperatures known to a person skilled in the art.

[0073] According to a preferred embodiment of the invention, steps a) and b) are carried out at a temperature ranging from 15 to 100 °C. Preferably, steps a) and b) are carried out at a temperature ranging from 15 to 25 °C. 3) Reinforcing load

[0074] The first rubber component and the second rubber component according to the invention comprise a reinforcing filler. Any type of reinforcing filler known for its ability to strengthen a rubber composition suitable for tire manufacturing may be used, for example, an organic filler such as carbon black, an inorganic reinforcing filler such as silica, alumina, or a blend of these two types of filler. More particularly, the reinforcing filler comprises at least silica, carbon black, or a mixture of silica and carbon black.

[0075] All carbon blacks are suitable as carbon blacks, particularly those of pneumatic grade. Among the latter, reinforcing carbon blacks of the 100, 200, or 300 series (ASTM grades) are particularly suitable, such as NI 15, N134, N234, N326, N330, N339, N347, N375, or, depending on the intended application, blacks of higher series (e.g., N660, N683, N772). Carbon blacks could, for example, already be incorporated into an isoprene elastomer in the form of a masterbatch (see, for example, applications WO 97 / 36724 or WO 99 / 16600).

[0076] Examples of organic fillers other than carbon blacks include functionalized polyvinyl organic fillers as described in applications WO-A-2006 / 069792, WO-A-2006 / 069793, WO-A-2008 / 003434 and WO-A-2008 / 003435.

[0077] The composition may contain one type of silica or a blend of several silicas. The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenated silica having a BET surface area and a CTAB specific surface area both less than 450 m2 / g, preferably from 30 to 400 m2 / g. Examples of highly dispersible precipitated silicas (HDS) include "Ultrasil 7000" and "Ultrasil 7005" silicas from Degussa, "Zeosil" 1165MP, 1135MP and 1115MP, 165GR silicas from Solvay, "Hi-Sil EZ150G" silica from PPG, "Zeopol" 8715, 8745 and 8755 silicas from Huber, treated precipitated silicas such as, for example, aluminium-doped silicas described in application EP-A-0735088 or high specific surface area silicas as described in application WO 03 / 16837.

[0078] According to one embodiment of the invention, the reinforcing filler is predominantly an inorganic reinforcing filler (preferably silica), that is to say, it comprises more than 50% (>50%) by weight of an inorganic reinforcing filler such as silica relative to the total weight of the reinforcing filler. Optionally, according to this embodiment, the reinforcing filler also comprises carbon black. According to this option, the carbon black is used at a rate less than or equal to 20%, more preferably less than or equal to 10% (for example, the carbon black content may be in the range of 0.5 to 20%, in particular from 1 to 10%). Within the indicated ranges, the coloring (black pigmenting agent) and anti-UV properties of carbon black are benefited, without otherwise compromising the typical performance provided by the inorganic reinforcing filler.

[0079] In the present exposition, the specific surface area BET 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 the standard NF ISO 5794-1, Annex E of June 2010 [multipoint volumetric method (5 points) - gas: nitrogen - degassing under vacuum: one hour at 160°C - relative pressure range w / in: 0.05 to 0.2].

[0080] For inorganic fillers such as silica for example, the CTAB specific surface area values ​​were determined according to standard NF ISO 5794-1, Annex G of June 2010. The process is based on the adsorption of CTAB (N-hexadecyl-N,N,N-trimethylammonium bromide) on the "external" surface of the reinforcing filler.

[0081] A person skilled in the art will understand that, as an equivalent filler to silica, a reinforcing filler of another nature, in particular organic, could be used, provided that this reinforcing filler is covered with a layer of silica, or has functional sites on its surface, in particular hydroxyl sites, requiring the use of a coupling agent to establish the bond between the filler and the elastomer.

[0082] The physical state in which the reinforcing charge is presented is indifferent, whether in the form of powder, microbeads, granules, balls or any other suitable densified form.

[0083] For the purposes of the invention, the total reinforcing filler content (carbon black and / or inorganic reinforcing filler such as silica) is from 5 to 150 parts per million, more preferably from 20 to 60 parts per million. Below 5 parts per million of filler, the composition may not be sufficiently reinforced, while above 150 parts per million of filler, the composition may have lower rolling resistance.

[0084] Preferably, silica is used as the major filler. Silica preferably represents more than 50% by mass of the reinforcing filler. In other words, the proportion of silica in the reinforcing filler is greater than 50% by weight of the total weight of the reinforcing filler. More preferably, silica represents more than 85% by mass of the reinforcing filler. According to some preferred embodiments, the silica content varies from 20% to 60%.

[0085] Carbon black, when present, is then used in a minority, preferably at a rate in the range of 0.1 to 10 pc, more preferably from 0.5 to 10 pc, in particular from 1 to 5 pc.

[0086] To couple the reinforcing inorganic filler to the diene elastomer, a coupling agent (or bonding agent) that is at least bifunctional can be used in a well-known manner to ensure sufficient chemical and / or physical connection between the inorganic filler (surface of its particles) and the diene elastomer. Organosilanes or polyorganosiloxanes that are at least bifunctional are used in particular. "Bifunctional" means 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 charge, and a second functional group comprising a sulfur atom, said second functional group being capable of interacting with the diene elastomer.

[0087] Preferably, the organosilanes are chosen from the group consisting of polysulfide organosilanes (symmetric or asymmetric) such as bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT and marketed under the name "Si69" by Evonik, or bis-(3-triethoxysilylpropyl) disulfide, abbreviated TESPD and marketed under the name "Si75" by Evonik, polyorganosiloxanes, mercaptosilanes, and blocked mercaptosilanes, such as "NXT-Silane" or "NXT-Z45 Silane" marketed by Momentive. Of course, mixtures of these coupling agents could also be used.

[0088] Those skilled in the art will understand that the coupling agent content depends on the amount of reinforcing inorganic filler to be coupled to the elastomer. Typically, the coupling agent content represents 0.5% to 15% by weight relative to the amount of reinforcing inorganic filler, particularly silica.

[0089] The first and second rubber components according to the invention may optionally also contain coupling activators, inorganic filler covering agents or more generally processing aids capable, in a known manner, through an improvement in the dispersion of the filler in the rubber matrix and a reduction in the viscosity of the composition, of improving its processing ability in the raw state, these agents being known elsewhere. 4) Crosslinking system

[0090] The crosslinking system can be any type of system known to those skilled in the art in the field of tire rubber compositions. In particular, it can be based on sulfur, and / or peroxide, and / or bismaleimides.

[0091] Preferably, the crosslinking system is sulfur-based; this is referred to as a vulcanization system. The sulfur can be supplied in any form, including molecular sulfur or a sulfur-donating agent. At least one vulcanization accelerator is also preferably present, and optionally, various known vulcanization activators such as zinc oxide, stearic acid, or equivalent compounds such as stearic acid salts and transition metal salts, guanidine derivatives (in particular diphenylguanidine), or known vulcanization retardants may be used.

[0092] Sulfur is used at a preferential rate of between 0.2 and 10 parts per annum, more preferably between 0.3 and 5 parts per annum. The vulcanization accelerator or mixture of accelerators is used at a preferential rate of between 0.5 and 10 parts per annum, more preferably between 0.5 and 5 parts per annum.

[0093] 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 and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds.

[0094] In a particular embodiment of the present invention, the assembly process further comprises a step c) which follows step b), said step c) consists of cross-linking the first and second assembled rubber components, by heating the assembled rubber components to a temperature of 100 to 200°C. 5) Possible additives

[0095] The first rubber component and the second rubber component useful for the purposes of the invention may optionally also include all or part of the usual additives commonly used in tire elastomer compositions, pigments, plasticizers, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents, reinforcing resins (as described for example in application WO 02 / 10269).

[0096] According to a preferred embodiment of the invention, the first rubber component and the second rubber component further comprise, independently of each other, at least one component selected from reinforcing fillers selected from carbon blacks and other reinforcing fillers, organic and inorganic of siliceous type in particular silica, as well as mixtures of these fillers, elastomer / filler coupling agents, non-reinforcing fillers, processing agents, stabilizers, plasticizers, pigments, antioxidants, anti-fatigue agents, anti-ozonating waxes, adhesion promoters, reinforcing resins, crosslinking systems based on sulfur and / or peroxide and / or bismaleimides, crosslinking activators including zinc monoxide and stearic acid, guanidic derivatives, extending oils, silica coating agents. 6) Preparation of the rubber compound

[0097] It goes without saying that the invention relates to the rubber components described above both in the so-called "raw" or non-crosslinked state (i.e., before cooking) and in the so-called "cooked" or crosslinked state, or even vulcanized (i.e., after crosslinking or vulcanization).

[0098] The first rubber component and the second rubber component useful for the needs of the invention according to the invention can be manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art: - a first thermomechanical working or mixing phase (the so-called "non-productive" phase), which can be carried out in a single thermomechanical step during which all the necessary constituents, including the elastomeric matrix, the reinforcing filler, and any other components, are introduced into a suitable mixer such as a standard internal mixer (for example, of the 'Banbury' type). Various additives, with the exception of the crosslinking system. The incorporation of any filler into the elastomer may be carried out in one or more stages by thermomechanical mixing. If the filler is already incorporated, in whole or in part, into the elastomer in the form of a master mix, as described, for example, in applications WO 97 / 36724 or WO 99 / 16600, the master mix is ​​mixed directly, and, if necessary, any other elastomers or fillers present in the composition that are not in the form of a master mix, as well as any other miscellaneous additives other than the crosslinking system, are incorporated.

[0099] - a second phase of mechanical work (the 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 lower temperature, typically below 120°C.

[0100] Such phases are well known to those skilled in the art.

[0101] The final composition thus obtained is then calendered, for example, into a sheet or plate, particularly for laboratory characterization, or extruded (or co-extruded with another rubber composition) into a semi-finished (or profile) rubber product usable in a tire, for example as a tread. These products can then be used for the manufacture of tires, according to techniques known to those skilled in the art.

[0102] The composition can be either in the raw state (before crosslinking or vulcanization), or in the cooked state (after crosslinking or vulcanization), can be a semi-finished product that can be used in a tire.

[0103] In the event that a crosslinking (or baking) step, where applicable vulcanization, is carried out, it is conducted in a known manner at a temperature generally between 100°C and 200°C, for a sufficient time which may vary for example between 5 and 90 min depending in particular on the baking temperature, the crosslinking system adopted and the crosslinking kinetics of the composition considered.

[0104] The rubber components used in the process of the invention can form, in whole or in part, a tread, an inner rubber or any other constituent layer of a tire.

[0105] The aforementioned features of the present invention, as well as others, will be better understood upon reading the following description of several examples of embodiments of the invention, given by way of illustration and not limitation. EXAMPLES OF THE INVENTION'S IMPLEMENTATION A) Tests and measurements Preparing examples

[0106] In the following examples the rubber components were made as described above. Characterization of the examples

[0107] In the examples, the properties of assemblies made of rubber components or mixtures are characterized before curing as indicated below. Raw tack:

[0108] Tack is the ability of an assembly of unvulcanized mixtures to resist pull-out stress.

[0109] A test device is used for measuring raw tack, which is inspired by US patent 005753822A and ASTM method D2979-95.

[0110] To prepare the mixing test specimens, mixing films are obtained by calendering to a thickness between 2 and 10 mm, depending on the type of mixture. The specimens are then cut with scissors to a size of 5 x 5 cm. An adhesive polypropylene plastic reinforcement can be added to strengthen the thinner specimens (approximately 2 mm).

[0111] An Instron tensile testing machine is then used, comprising a fixed metal jaw and a movable metal jaw. A first test specimen consisting of a mixture film with a thickness between 2 and 10 mm is mechanically fixed to the fixed jaw. A second test specimen consisting of a mixture film with a thickness between 2 and 10 mm is mechanically fixed to the movable jaw.

[0112] The measurement principle consists of bringing the two mixture films into contact (with or without solvent coating on a surface of the rubber component, if it is a control test) for 5 seconds by applying a compressive force of 40 N. After this contact phase, they are separated by driving the crosshead of the tensile testing machine. The crosshead's displacement speed during this separation phase is Imm / s. The crosshead displacement and the force are measured continuously as a function of time during the contact and separation phases.

[0113] The raw sticking result is the measurement of the maximum force (in Newtons, N) reached during the tearing.

[0114] The results are expressed in base 100, that is to say that the value 100 is arbitrarily assigned to a control (assembly without coating), to then compare the raw stickiness of the different assemblies tested, the higher the value, the stronger the raw stickiness. B) Examples

[0115] The examples presented below are intended to compare the raw stickiness of the components (Cl and C2) assembled according to the invention (Al, A2 and A3), with the stickiness raw of these same components whose assembly is done without solvent coating (Tl).

[0116] Tables 1 and 2 present the components tested (in pc), as well as the results obtained.

[0117] The rubber components are manufactured by introducing all the constituents into an internal mixer, with the exception of the vulcanizing system. The vulcanizing agents (sulfur and accelerator) are introduced into an external mixer at low temperature (the constituent cylinders of the mixer being at approximately 30°C).

[0118] [Tables 1] pce Components Cl C2 NR (1) 100 100 Carbon black 22 52 Silica (2) 25 Antioxidant 2.5 1.5 Si69 (3) 2.5 Vulcanization accelerator 2 0.9 Cobalt salt (4) 1 Sulfur 0.8 7 Stearic acid (5) 2 0.6 Zinc oxide (6) 3 9

[0119] (1) NR (2) Solvay Zeosil 165GR (3) Si69: Bis 3-triethoxysilylpropyltetrasulfide (4) Cobalt (II) naphthenate (5) Stearic acid marketed under the reference "Pristerene 4931" by the company Uniqema (6) Industrial grade zinc oxide - Umicore company

[0120] The aliphatic solvent is applied to a surface of the first mixture Cl (or rubber component Cl) in a homogeneous raw manner at a rate of 1.5 to 3 mg / cm2.

[0121] Three bio-based aliphatic solvents Isane 250, Isane 270 and Isane 290 from the Isane Biolife® range from Total Energies were used in the Al to A3 assemblies respectively.

[0122] After a resting period allowing the excess solvent to be eliminated by migration and the sticky interface to be created, the two Cl and C2 mixtures are joined and the raw stickiness measurement is carried out at 23 °C with the method. C) Results

[0123] [Tables2] Example Tl Al A2 A3 Raw tights (Base 100) 100 246 265 283

[0124] Compared to the control example Tl, it is noted that the examples according to the invention Al to A3 exhibit a significantly superior raw stickiness.

Claims

Demands

1. A method for assembling two rubber components comprising the following steps of: a. coating a surface of a first rubber component with an aliphatic solvent, which aliphatic solvent is selected from the group consisting of hydrocarbon compounds with linear, branched or cyclic Ci6-C2o chains, distillation fractions (cuts) comprising said hydrocarbon compounds, and mixtures of said hydrocarbon compounds, b. affixing a second rubber component to the coated surface of the first rubber component.

2. A method according to claim 1, wherein the aliphatic solvent has a flash point ranging from 107 to 160 °C, the flash point being measured according to ASTM D93.

3. A process according to any one of claims 1 to 2, wherein the aliphatic solvent is selected from distillation cuts with boiling points ranging from 244°C to 269°C, distillation cuts with boiling points ranging from 265°C to 310°C and distillation cuts with boiling points ranging from 290°C to 320°C, the boiling point being measured according to ASTM D86.

4. A process according to any one of claims 1 to 3 wherein the aliphatic solvent is a cut of isoalkanes, preferably obtained from raw materials of vegetable origin.

5. A method according to any one of the preceding claims, wherein the aliphatic solvent is applied to the surface of the first rubber component at a concentration less than or equal to 10 mg / cm2, preferably less than or equal to 5 mg / cm2.

6. A method according to any one of the preceding claims, wherein the first rubber component and the second rubber component are independently of each other non-crosslinked or crosslinked.

7. A method according to any one of the preceding claims, wherein at least one of the first rubber component and the second rubber component is non-crosslinked.

8. A method according to any one of the preceding claims, wherein the first rubber component and the second rubber component are non-crosslinked.

9. A method according to any one of the preceding claims, wherein the first rubber component and the second rubber component comprise, independently of each other, one or more elastomers selected from polychloroprene, butyl rubbers, natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (PB), nitrile rubbers (NBR), poly(isoprene-styrene), poly(isoprene-butadiene), poly(styrene-butadiene) (SBR), isoprene, styrene and butadiene terpolymers, ethylenic polymers, poly(ethylene-butadiene) (EBR) and mixtures thereof.

10. A method according to any one of the preceding claims, wherein the first rubber component and the second rubber component comprise, independently of each other, one or more elastomers selected from butyl rubbers, natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (PB), poly(isoprene-styrene), poly(isoprene-butadiene), poly(styrene-butadiene) (SBR), isoprene, styrene and butadiene terpolymers, poly(ethylene-butadiene) (EBR) and mixtures thereof.

11. A method according to any one of the preceding claims, wherein at least one of the first rubber component and the second rubber component comprises, independently of each other, a diene elastomer, preferably highly unsaturated.

12. A method according to any one of the preceding claims, wherein the first rubber component and the second rubber component further comprise, independently of each other, at least one component selected from reinforcing fillers selected from carbon blacks and other reinforcing fillers, organic and inorganic of the siliceous type, in particular silica, as well as mixtures of these fillers, elastomer / filler coupling agents, non-reinforcing fillers, processing agents, stabilizers, plasticizers, pigments, antioxidants, anti-fatigue agents, anti-ozonating waxes, adhesion promoters, reinforcing resins, sulfur-based and / or peroxide-based and / or bismaleimide crosslinking systems, crosslinking activators including zinc monoxide and stearic acid, guanidic derivatives, extending oils, silica coating agents.

13. A method according to any one of the preceding claims, wherein step a) and step b) are carried out at a temperature from 15 to 100 °C.

14. A method according to any one of the preceding claims, further comprising a step c) which follows step b) of crosslinking the first and second assembled rubber components, by heating the assembled rubber components to a temperature of 100 to 200°C.

15. A method according to any one of claims 1 to 14 wherein the two rubber components constitute semi-finished articles for tires.