JP2023546448A - A reinforcing article comprising at least one metal reinforcing element and a rubber composition. - Google Patents

Abstract

The present invention relates to reinforced products based on at least one metal reinforcing element embedded in a rubber composition based on a crosslinking system comprising at least one epoxidized diene elastomer, a reinforcing filler, and at least 1 phr of sulfur. [Selection diagram] None

Description

The present invention relates to the field of reinforced rubber products, in particular for pneumatic or non-pneumatic tires, and to molded articles comprising such reinforced products.

Reinforcing plies of pneumatic tires or reinforced rubber articles typically include a "calendered" rubber composition and metal reinforcing cords. The calendering composition needs to exhibit very specific properties such as good adhesion to metal reinforcing cords, rupture properties and hysteresis properties, giving the ply good durability and low rolling resistance over the life of the tire.

Adhesion between the metal cord and the surrounding rubber is therefore an important property for the effectiveness of reinforcing plies in pneumatic tires or reinforcing rubber articles. Coating compositions containing diene elastomers, particularly natural rubber, reinforcing fillers, and vulcanization systems that are very specific for these compositions are known in the art. This vulcanization system usually contains high contents of sulfur and zinc oxide, low contents of stearic acid, "slow" vulcanization accelerators and vulcanization retarders. In these systems, the adhesion between the rubber mixture and the metal cord takes place via the sulfidation phenomenon of the brass-coated surface of the cord. Therefore, vulcanization retarders and "slow" vulcanization accelerators are used to allow the sulfur to sulfurize the metal cord before it is consumed by vulcanization.

Much research has been conducted by pneumatic tire manufacturers to improve one or more of the performance qualities of calendering compositions and further improve their durability.

Document WO 2016/058943 discloses a reinforcement product comprising a rubber composition coating a sheathed reinforcement thread, the composition comprising a diene elastomer, a reinforcement filler, and Based on a vulcanization system containing a "rapid" vulcanization accelerator according to the defined term, the composition exhibits excellent resistance to aging.

Document WO 2019/122586 discloses a composition comprising an adhesion promoter that is substantially free of molecular sulfur and exhibits good adhesion and stiffness performance qualities, which composition is subjected to processes other than vulcanization. It is possible to crosslink by various crosslinking systems.

More recently, document WO 2020/058614 describes at least one elastomer exhibiting epoxide groups, at least one reinforcing filler, polycarboxylic acid, imidazole and Rubber compositions based on crosslinking systems containing at least one specific polyphenolic compound are taught.

Compositions utilizing crosslinking systems in place of vulcanization, although highly effective, represent a relative industrial complexity due to the variety of their constituent materials.

International Publication No. 2016/058943 International Publication No. 2019/122586 International Publication No. 2020/058614 US Patent Publication No. 2003/120007 European Patent No. 0 763 564 US Patent No. 6,903,165 European Patent No. 1 403 287 US Patent Publication No. 2011/0098404 International Application No. 97/36724-A2 International Application No. 99/16600-A1 International Application No. 2006/069792-A1 International Application No. 2006/069793-A1 International Application No. 2008/003434-A1 International Application No. 2008/003435-A1 International Application No. 03/016215-A1 International Application No. 03/016387-A1 International Application No. 02/10269 French Patent No. 2 981 298

Kautsch. Gummi Kunst. , 2004, 57(3), 82 J. Appl. Polym. Sci. , 1999, 73, 1733 Macromolecules, 1998, 31, 2822) "The Journal of the American Chemical Society" (Volume 60, page 309, February 1938)

The applicant's company has continued this research and has developed a reinforced product based on at least one metal reinforcing element embedded in a rubber composition based on at least one epoxidized diene elastomer, which composition Cross-linked by sulfuric acid and therefore easy to use industrially, it shows excellent adhesion properties of the composition to reinforcing elements and improves the durability of the performance qualities, especially in terms of breaking properties and rolling resistance. discovered.

The present invention relates to at least one reinforced product based on at least one metal reinforcing element embedded in a rubber composition based on at least one epoxidized diene elastomer, a reinforcing filler, and a crosslinking system containing at least 1 phr of sulfur.

Preferably, the present invention relates to reinforced products in which the crosslinking system contains 1 to 5 phr sulfur, preferentially 1 to 4 phr sulfur, and preferably 1 to 2.5 phr sulfur.

Preferably, the invention provides that the vulcanization system further comprises between 0.1 and 6 phr, more preferentially between 0.5 and 4 phr, and very preferentially between 0.5 and 2.5 phr. Concerning reinforcing products containing vulcanization accelerators used in content.

Preferably, the invention relates to a reinforced product in which the crosslinking system comprises a vulcanization accelerator which exhibits a vulcanization onset time, referred to as "t0", of less than 3.5 minutes, preferably 3 minutes or less.

Preferably, the invention relates to a reinforced product in which the reinforcing filler comprises silica as a main component.

Preferably, the invention relates to reinforced products, the rubber composition further comprising a compound of the guanidine family, preferentially diphenylguanidine. Preferably, the content of compounds of the guanidine group ranges from 0.5 to 3 phr, preferentially from 0.5 to 2.5 phr, and preferably from 0.5 to 2 phr.

Preferably, the present invention relates to reinforced products in which the degree of epoxidation of the epoxidized diene elastomer is in the range from 5% to 40%, preferably from 10% to 35%.

Preferably, the invention provides that the epoxidized diene elastomer is epoxidized natural rubber, epoxidized synthetic polyisoprene, preferentially epoxidized polybutadiene with a content of more than 90% of cis-1,4 bonds, epoxidized butadiene/ It relates to a reinforcing product selected from the group consisting of copolymers of styrene and mixtures of these elastomers, preferentially selected from the group consisting of epoxidized natural rubber and epoxidized synthetic polyisoprene.

In a particular arrangement, the invention provides that the rubber composition is further selected from the group consisting of polybutadiene, natural rubber, synthetic polyisoprene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers, preferentially natural rubber and synthetic The present invention relates to a reinforced product comprising a non-epoxidized diene elastomer selected from polyisoprene. In this particular arrangement, the content of non-epoxidized diene elastomer is preferentially between 0 and 49 phr, preferably between 0 and 40 phr, preferentially between 5 and 25 phr.

In another particular arrangement, the invention relates to a reinforced article in which the rubber composition comprises one or more epoxidized diene elastomers for the sole elastomer.

Preferably, the invention provides that the rubber composition is free of cobalt salts or contains less than 2 phr, preferentially less than 1 phr, in a preferred embodiment less than 0.5 phr, and very preferentially less than 0.1 phr of cobalt salts. Concerning reinforcing products including.

Preferably, the invention provides that the rubber composition does not contain or contains less than 2 phr, preferentially less than 1 phr, in a preferred embodiment less than 0.5 phr, very preferentially less than 0.5 phr of stearic acid or one of its derivatives. Reinforcement products containing less than 0.1 phr.

Preferably, the present invention provides that the rubber composition comprises an auxiliary agent selected from a silica coupling auxiliary agent and an auxiliary agent for covering the silica, and mixtures thereof, and the content of the auxiliary agent is in proportion to the amount of silica. The reinforcing product ranges from 5% to 20% by weight relative to the amount of silica, preferentially from 6% to 18% by weight relative to the amount of silica. Preferably, the auxiliary agent for the coupling of silica is selected from organosilanes, in a preferred embodiment from the group consisting of organosilane polysulfides, polyorganosiloxanes, mercaptosilanes and blocked mercaptosilanes, very preferably: Selected from the group consisting of organic silane polysulfides. Preferably, the auxiliary agent for covering the silica is selected from alkyl alkoxysilanes, polyols, polyethers, primary, secondary, tertiary amines or polyorganosiloxanes, very preferentially from alkyl alkoxysilanes.

Preferably, the invention relates to a reinforced product in which the rubber composition comprises at most 4 phr zinc oxide, preferentially at most 3 phr zinc oxide, preferentially at most 2.5 phr zinc oxide.

Preferably, the invention relates to reinforced products having a total reinforcing filler content of 10 to 200 phr, preferably 10 to 100 phr, and in a preferred embodiment 25 to 75 phr.

Preferably, the invention provides that the metal reinforcement is made of a metal selected from the group consisting of copper, zinc, tin, aluminium, cobalt, nickel and alloys containing at least one of these metals, preferentially copper, tin. , zinc or alloys containing at least one of these metals. Preferably, the metal of the metal surface of the metal reinforcement is brass.

The invention also relates to finished or semi-finished products comprising the reinforcing product according to the invention.

The invention also relates to a pneumatic or non-pneumatic tire comprising a reinforcing product according to the invention.

(definition)
The expression "based on" is to be understood as meaning a product or composition comprising a mixture of the various constituents used and/or a product of an in situ reaction, in which some of these constituents are , it is possible and/or intended to react with each other at least partially during the various stages of production of the composition, so that the product or composition is completely or partially crosslinked. It is possible to be in a cross-linked state or in a non-crosslinked state.

The expression "parts by weight per hundred parts by weight of elastomer (or phr)" is to be understood within the meaning of the invention to mean parts by weight per hundred parts by weight of elastomer.

In this specification, all percentages (%) expressed are weight percentages (%) unless otherwise specified.

Furthermore, any range indicated by the expression "between a and b" refers to a range greater than a and extending less than b (i.e., this interval excluding a, b); '' means a range extending from a up to b (ie, including the strict limits a, b).

The carbon-containing compounds described herein can be of fossil or bio-based origin. In the latter case, it may originate partially or completely from biomass or be obtained from renewable raw materials originating from biomass. In particular, polymers, plasticizers, fillers, etc. are applicable.

(Reinforced product)
The reinforced product according to the invention is based on at least one metal reinforcing element embedded in a rubber composition based on at least one epoxidized diene elastomer, a reinforcing filler, and a crosslinking system containing at least 1 phr of sulfur.

(Epoxidized diene elastomer)
Epoxidized elastomer or rubber (the two terms are synonymous and synonymous in a known manner) is understood by those skilled in the art to be a homopolymer or a block, statistical or other copolymer, having elastomeric properties. It is understood to mean any type of elastomer within the known meaning, which refers to epoxide-based (or epoxidized), ie containing epoxide groups. The expressions "diene elastomer containing epoxide groups" or "epoxidized diene elastomer" are used interchangeably.

Epoxidized diene elastomers are, in a known manner, solid at ambient temperature (20° C.); solidity means that it exists only under the influence of gravity at ambient temperature (20° C.) after at least 24 hours. It is understood to mean any material that does not have the ability to assume the final shape of a container.

The glass transition temperature Tg of the elastomer described herein is measured by a known method by DSC (differential scanning calorimetry), for example, according to ASTM standard D3418 of 1999, unless otherwise specified.

The rubber composition of the reinforced product according to the invention may be a single epoxidized diene elastomer or a mixture of epoxidized diene elastomers (hereinafter referred to as "epoxidized diene elastomer" to refer to the sum of the epoxidized diene elastomers of the composition). ) containing epoxide groups in combination with any type of non-epoxidized elastomer, such as a diene elastomer, indeed an elastomer other than a diene elastomer. Diene elastomers can be used.

The epoxidized diene elastomer is the main component in the rubber composition according to the invention, ie it is the only elastomer or it accounts for the greatest mass of the elastomers in the composition.

According to a preferred embodiment of the invention, the rubber composition comprises from 51 to 100 phr, preferably from 60 to 100 phr, in a preferred embodiment from 75 to 95 phr of an epoxidized diene elastomer as the main component, from 0 to 49 phr, preferably from 0 to 40 phr, and in preferred embodiments from 5 to 25 phr, in combination with one or more other minor non-epoxidized elastomers.

Preferably, the few non-epoxidized elastomers are selected from the group consisting of polybutadiene, natural rubber, synthetic polyisoprene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers, preferentially selected from natural rubber and synthetic polyisoprene. It is a non-epoxidized diene elastomer.

According to another preferred embodiment of the invention, the composition comprises one or more epoxidized diene elastomers for a total of 100 phr of elastomer.

The degree of epoxidation (mol%) of the epoxidized diene elastomer can vary over a wide range depending on the particular embodiment of the invention, preferably within the range of 0.1% to 80%, preferentially 0.1% to 80%. It is within the range of 1 to 50%, more preferably within the range of 0.3 to 50%. If the degree of epoxidation is less than 0.1%, the desired technical effect may be insufficient, while if it exceeds 80%, the inherent properties of the polymer will deteriorate. For these reasons, the degree of functionalization, especially epoxidation, is more preferentially within the range from 5% to 40%, advantageously within the range from 10% to 35%.

Epoxidized diene-type elastomers are to be understood as meaning elastomers resulting at least partially (i.e. homopolymers or copolymers) from diene monomers (monomers with two conjugated or non-conjugated carbon-carbon double bonds). It is recalled that this polymer is functionalized, ie contains epoxide functional groups.

The first characteristic of epoxidized diene elastomers is that they are diene elastomers. These diene elastomers are non-thermoplastic by the definition of this patent application, exhibit negative Tg's (i.e. below 0°C) in the vast majority of cases, and are defined as "essentially unsaturated" by known methods. They can be divided into two categories: those called "essentially saturated" and those called "essentially saturated." Butyl rubbers, such as copolymers of dienes and α-olefins of the EPDM type, essentially fall into the category of saturated diene elastomers, with a low or very low content of units derived from dienes, always less than 15% (mol%). . In contrast, essentially unsaturated diene elastomers are diene elastomers that result at least in part from conjugated diene monomers and have a content of diene-derived units (conjugated dienes) greater than 15% (mol%). is understood to mean. Within the category of "essentially unsaturated" diene elastomers, "highly unsaturated" diene elastomers specifically refer to diene elastomers having a content of diene-derived units (conjugated dienes) greater than 50% (mol%). understood to mean.

At least one diene elastomer of highly unsaturated type, in particular a diene elastomer selected from the group consisting of natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (BR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers. It is desirable to use Such copolymers are more preferentially butadiene/styrene copolymers (SBR), isoprene/butadiene copolymers (BIR), isoprene/styrene copolymers (SIR), isoprene/butadiene/styrene copolymers (SBIR) and copolymers of these. selected from the group consisting of mixtures.

A second essential characteristic of the epoxidized diene elastomers used in the requirements of the present invention is that they are functionalized by containing epoxide functionality.

The epoxide groups present in diene elastomers are obtained by copolymerization or post-polymerization modification and, depending on the method of preparation, are carried directly by the backbone of the chain or by pendant groups, e.g. This is carried out by epoxidation or any other modification of the diene functionality present in the chain.

Epoxidized diene elastomers can be prepared, for example, by epoxidation of equivalent non-epoxidized diene elastomers, e.g. by chlorohydrin-based processes, bromohydrin-based processes, or by hydrogen peroxide, alkyl hydroperoxides, peracids (such as peracetic acid or perpic acid). It can be obtained in a known manner by a process based on; in particular Kautsch. Gummi Kunst. , 2004, 57(3), 82. As a result, epoxide groups are present in the polymer chain. In particular, mention may be made of epoxidized natural rubber (abbreviated as "ENR"), such ENR being produced by, for example, ENR-25 and ENR-50 (with a degree of epoxidation of 25% and 50%, respectively) from Guthrie Polymer. %). Epoxidized BR is also well known per se and is sold, for example, by Sartomer under the name Poly Bd (eg Poly Bd 605E). Epoxidized SBR can be prepared by epoxidation techniques well known to those skilled in the art.

Diene elastomers with epoxidized groups are described, for example, in US Pat.

Preferentially, the epoxidized diene elastomers are epoxidized natural rubber (NR) (abbreviated as "ENR"), epoxidized synthetic polyisoprene (IR), preferentially containing more than 90% of cis 1,4-bonds. epoxidized polybutadiene (BR), epoxidized butadiene/styrene copolymer (SBR) and mixtures of these elastomers.

Epoxidized diene elastomers can exhibit pendant epoxide groups. In this case, they can be modified by post-polymerization modification (see, for example, J. Appl. Polym. Sci., 1999, 73, 1733) or by diene monomers and monomers having epoxide groups, in particular esters of methacrylic acid having epoxide groups. This radical polymerization, for example, of glycidyl methacrylate (in particular in bulk, in solution or in a dispersion medium - in particular in a dispersion, emulsion or suspension) is well known to those skilled in the art in the synthesis of polymers; for example, the following references may be mentioned: (Macromolecules, 1998, 31, 2822) or by using a nitrile oxide having an epoxide group. For example, the document US Patent Publication No. 2011/0098404 describes the emulsion copolymerization of 1,3-butadiene, styrene and glycidyl methacrylate.

Reinforcing Filler The rubber composition of the reinforced product according to the invention comprises one or more reinforcing fillers.

Any type of "reinforcing" filler known for its ability to reinforce rubber compositions that can be used in particular in the manufacture of tires, for example organic fillers such as carbon black, inorganic fillers such as silica, or fillers of these two types. A mixture of can be used.

All carbon blacks are suitable as carbon blacks, especially the blacks conventionally used in tires or their treads. Of the latter, more particularly reinforcing carbon blacks of the 100, 200 and 300 series, or 500, 600 or 700 series blacks (ASTM D-1765-2017 grades) (e.g. N115, N134, N234, N326, N330, N339, N347, N375, N550, N683 or N772 Black). These carbon blacks can be used in isolated form as commercially available or in any other form, e.g. as a support for some of the rubber additives used. . Carbon black may already be incorporated into diene elastomers, especially isoprene-based elastomers, for example in the form of masterbatches (see, for example, International Application No. 97/36724-A2 and International Application No. 99/16600-A1). reference). Also suitable are carbon blacks resulting from tire recycling, blacks resulting from the pyrolysis of pneumatic tires, such as the 500 series Enviro CB P550 black manufactured by Scandinavian Enviro Systems.

Examples of organic fillers other than carbon black include International Application No. 2006/069792-A1, International Application No. 2006/069793-A1, International Application No. 2008/003434-A1, and International Application No. 2008/003435-A1. Mention may be made of functionalized polyvinyl organic fillers as described.

"Reinforcing inorganic filler" as used herein means "white" filler, "clear" filler, or "non-black" filler, whatever its color and origin (natural or synthetic), as opposed to carbon black. Also referred to as filler is to be understood as meaning any inorganic or mineral filler which can alone reinforce the rubber composition intended for the production of tires, without any means other than intermediate coupling aids. In a known manner, some reinforcing inorganic fillers can be characterized in particular by the presence of hydroxyl (--OH) groups on their surface.

Mineral fillers based on silicon, especially silica (SiO ₂ ) or alumina, especially alumina (Al ₂ O ₃ ) are particularly suitable as reinforcing inorganic fillers. The silica used is any reinforcing silica known to the person skilled in the art, in particular those with both BET and CTAB specific surfaces of less than 450 m2/g, preferably from 30 to 400 m2/g, especially from 60 to 300 m2/g. It may be a precipitated silica or a fumed silica exhibiting a range of 100 g. Any type of precipitated silica can be used, especially highly dispersed precipitated silica (referred to as "HDS" as "highly dispersed" or "highly dispersed silica"). These precipitated silicas, either highly dispersed or not, are well known to those skilled in the art. Mention may be made, for example, of the silicas described in International Application No. 03/016215-A1 and International Application No. 03/016387-A1. In particular, among the commercially available HDS silicas, Evonik's Ultrasil® 5000GR and Ultrasil® 7000GR silicas or Solvay's Zeosil® 1085GR, Zeosil® 1115 MP, Zeosil® 11 65MP , Zeosil® Premium 200MP and Zeosil® HRS 1200 MP silicas can be used. As non-HDS silicas, the following commercially available silicas: 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 from PPG, Hi-Sil 210, HiSil HDP 320G silica and K-160 from Wilmar can be used.

In the present disclosure, the BET specific surface is determined using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" (Volume 60, Page 309, February 1938), and more specifically, Standards of June 2010 NF ISO 5794-1, Appendix E [Multi-point (5-point) volumetric method - Gas: Nitrogen - Degassing under vacuum: 1 hour at 160 °C - Range of relative pressure p/p0: 0. 05-0.17] by gas adsorption.

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

For carbon black, the STA specific surface is determined according to standard ASTM D6556-2016.

The physical state in which the reinforcing inorganic filler is provided is not critical, whether it is in the form of a powder, microbeads, granules, beads or any other It does not matter whether it is in a suitable high-density form. Of course, it is understood that reinforcing inorganic fillers also mean mixtures of different reinforcing inorganic fillers, especially mixtures of silicas as mentioned above.

Preferably, the content of total reinforcing fillers (reinforcing inorganic fillers such as carbon black and/or silica) is between 10 and 200 phr, more preferentially between 10 and 100 phr, very preferentially between 25 and 75 phr, optimally varies depending on the specific application in question in a known manner.

Preferentially, the reinforcing filler of the rubber composition comprises silica as a main component. As main component is understood to mean that the silica accounts for more than 50% of the total weight of the reinforcing filler.

If the reinforcing filler contains silica, preferentially silica as the main component, the rubber composition of the reinforcing product according to the invention may contain auxiliary agents for coupling the silica and auxiliary agents for covering the silica, as well as these. The mixture preferentially comprises an auxiliary agent selected from the mixture, the content of the auxiliary agent ranging from 5% to 20% by weight relative to the amount of silica, preferentially from 6% to the amount of silica. The range is up to 18% by weight.

Coupling aids are at least difunctional coupling agents intended to provide a satisfactory connection of chemical and/or physical properties between the inorganic filler (the surface of its particles) and the epoxidized diene elastomer. It is understood to mean an auxiliary agent (or binder). In particular, organic silanes or polyorganosiloxanes which are at least difunctional are used. "Bifunctional" is understood to mean a compound having a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the epoxidized diene elastomer. . For example, such bifunctional compounds may include a first functional group containing a silicon atom that can interact with the hydroxyl groups of the inorganic filler and a second functional group containing a sulfur atom that can interact with the diene elastomer. and a functional group.

Preferentially, the organic silane is bis(3-triethoxysilylpropyl)tetrasulfide, abbreviated TESPT, sold by Evonik under the name Si69, or bis(3-triethoxysilylpropyl)tetrasulfide, abbreviated TESPT, sold by Evonik under the name Si75. -Organosilane polysulfide (symmetrical or asymmetric) such as triethoxysilylpropyl) disulfide, abbreviated as TESPD, polyorganosiloxane, mercaptosilane, S-(3-(triethoxysilyl)) sold by Momentive under the name NXT silane selected from the group consisting of block mercaptosilanes such as propyl) octane thioate. More preferentially, the organosilane is an organosilane polysulfide.

Coating agent is understood to mean an auxiliary agent which does not provide a bond between the filler and the elastomeric matrix in a manner known to those skilled in the art. By bonding via covalent bonds in a known manner to the surface functional sites of the inorganic filler, for example to the surface hydroxyl sites of the silica when the reinforcing inorganic filler is silica, the coating agent improves the processability of the composition. and reduce the viscosity of the composition in its uncured state.

In a known manner, processing aids that can improve the ease of processing in the uncured state on the basis of increasing the dispersibility of inorganic fillers in the rubber matrix and reducing the viscosity of the composition are generally used in coatings. These processing aids are, for example, hydrolyzable silanes, such as alkylalkoxysilanes (especially alkyltriethoxysilanes), polyols, polyethers (e.g. polyethylene glycol), primary, secondary or tertiary amines (eg trialkanolamines), or hydroxylated or hydrolyzable POSs, such as α,ω dihydroxypolyorgansiloxanes (particularly α,ω dihydroxypolydimethylsiloxanes).

(Crosslinking system)
The rubber composition of the reinforced product according to the invention comprises a sulfur-based crosslinking system, called a vulcanization system, containing at least 1 phr of sulfur.

Sulfur can be provided in any form, particularly in the form of molecular sulfur or a sulfur donor.

The composition of the reinforced product according to the invention has a low sulfur content. Sulfur is used in a content ranging from 1 to 5 phr, preferentially from 1 to 4 phr, very preferably from 1 to 2.5 phr.

Preferably, the crosslinking system comprises a "rapid" vulcanization accelerator, ie, an accelerator exhibiting a vulcanization onset time, referred to as "t ₀ ", of less than 3.5 minutes, preferably 3 minutes or less.

The t ₀ value for a given accelerator needs to be measured in a given rubber composition at a given vulcanization temperature. In order to compare "slow" or "fast" accelerators according to _t0 values, here we have as reference compositions NR100 phr, carbon black N326 47 phr, stearic acid 0.9 phr, ZnO 7.5 phr, sulfur 4.5 phr and Given a composition containing an accelerator, whose t ₀ is to be determined at a molar content of 2.3 mmol per 100 parts by weight of elastomer (commercial references for the components shown here are the components used in Example 1). ). The method for measuring t ₀ is based on the standard DIN-53529 at 150°C. Within the meaning of this patent application, "t ₀ " means t ₀ as defined and measured above.

For example, in the proposed formulation, the _to of a particular accelerator according to the proposed measurement method is shown in Table 1 below. DCBS represents N,N-dicyclohexyl-2-benzothiazolesulfenamide, TBBS represents N-tert-butyl-2-benzothiazolesulfenamide, and CBS represents N-cyclohexyl-2-benzothiazolesulfenamide. It shows.

[Table 1]

Preferentially, the vulcanization accelerator is selected from the group consisting of compounds of the thiuram family, derivatives of thiocarbamates, sulfenamides, thiophosphates and mixtures thereof, the t ₀ of which is less than or equal to 3 and a half minutes, preferably 3 and a half minutes. Less than a minute. Very preferentially, the rubber composition of the reinforced product according to the invention comprises N-cyclohexyl-2-benzothiazole sulfenamide as vulcanization accelerator.

The vulcanization accelerator is used in a preferential content of 0.1 to 6 phr, more preferentially 0.5 to 4 phr, very preferentially 0.5 to 2.5 phr.

Preferably, the rubber composition of the reinforced product according to the invention comprises at least 0.5 phr zinc oxide, preferentially at least 1 phr zinc oxide. Preferentially, the rubber composition of the reinforced product according to the invention comprises at most 5 phr zinc oxide, preferentially at most 3 phr zinc oxide.

(Additive)
The rubber composition of the reinforced product according to the invention may also contain other reinforcing or non-containing materials such as plasticizers (such as plasticizing oils and/or plasticizing resins), fillers (such as recycled or desulphurized crumbs resulting from recycling pneumatic tires, etc.). reinforcement), pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants or antioxidants, anti-fatigue agents or reinforcing resins (such as those described in International Application No. 02/10269), etc. known to those skilled in the art. It may also contain all or some of the usual additives and processing aids particularly used in rubber compositions for pneumatic tires.

The formulation of the rubber composition of the reinforced product according to the invention makes it possible to minimize the use of cobalt salts, and even to eliminate them, while maintaining good adhesive properties. Therefore, in a preferred arrangement, the rubber composition of the reinforced product according to the invention contains no or less than 2 phr, preferentially less than 1 phr, in a preferred embodiment less than 0.5 phr, very preferentially 0 phr of cobalt salts. Contains less than .1 phr.

Furthermore, the formulation of the rubber composition of the reinforced product according to the invention makes it possible to minimize, in fact even eliminate, the use of stearic acid or one of its derivatives. The rubber composition of the reinforced product according to the invention therefore contains no or less than 2 phr, preferentially less than 1 phr, in a preferred embodiment less than 0.5 phr, very preferentially less than 0.5 phr of stearic acid or one of its derivatives. includes less than 0.1 phr.

The rubber composition of the reinforced product according to the invention can furthermore contain compounds of the guanidine family, preferentially diphenylguanidine. It has been observed that the presence of compounds of the guanidine group, preferentially diphenylguanidine, makes it possible to further improve the adhesion properties of the rubber composition to metal reinforcements.

Preferably, the content of compounds of the guanidine group ranges from 0.5 to 3 phr, preferentially from 0.5 to 2.5 phr, preferably from 0.5 to 2 phr.

(reinforcing element)
The reinforced product according to the invention is based on at least one metallic reinforcing element embedded in a rubber composition.

The expression "based on at least one metal reinforcing element embedded in a rubber composition" is to be understood to mean a reinforcing product comprising a reinforcing element and said composition, at various stages of the production of the reinforcing product. It is possible for the composition to react with the surface of the reinforcing element, especially during crosslinking of the composition or during the manufacture of the reinforced product before crosslinking of the composition.

Said metallic reinforcing element is a thread-like element. The metal reinforcing element can be completely or partially made of metal.

In certain arrangements, the reinforcing element includes a metal surface.

The metal surface of the reinforcing element constitutes at least a part, preferentially all, of the surface of the element and is intended to be in direct contact with the rubber composition. Preferably, the reinforcing element is metallic, ie composed of a metallic material.

The rubber composition coats at least a portion of the reinforcing element, preferentially all of said reinforcing element.

According to a first alternative of the invention, the metal surface of the reinforcing element is made of a different material than the rest of the reinforcing element. In other words, the reinforcing element is made of a material that is at least partially covered, and preferentially completely covered, by the metal layer that constitutes the metal surface. The material covered at least partially and preferentially completely with a metal surface can be metallic or non-metallic, preferably metallic.

According to a second alternative of the invention, the reinforcing element is made of one and the same material, in which case the reinforcing element is made of the same metal as the metal of the metal surface.

The metal surface can, for example, improve the processing properties of the reinforcing element or the use properties of the reinforcing product and/or the pneumatic tire itself, such as adhesive properties, corrosion resistance, aging resistance, etc.

According to one embodiment of the invention, the metal surface comprises a metal selected from the group consisting of copper, zinc, tin, aluminum, cobalt, nickel, and alloys comprising at least one of these metals. The alloy can be a binary or ternary alloy, such as bronze and brass, for example. Preferably, the metal of the metal surface is copper, tin, zinc, or an alloy containing at least one of these metals. More preferentially, the metal of the metal surface is brass (Cu--Zn alloy), zinc or bronze (Cu--Sn alloy), more preferably also brass.

Since certain metals are susceptible to oxidation when in contact with ambient air, the metal may become partially oxidized.

According to a preferred embodiment, the reinforced product according to the invention comprises a plurality of reinforcing elements as defined above and a calendered rubber in which the reinforcing elements are embedded, the calendered rubber being the rubber of the reinforcing product according to the invention. consisting of a composition. According to this embodiment, the reinforcing elements are generally arranged side by side along the main direction. In the envisaged application in tires, the reinforcing product according to the invention can constitute a reinforcement for tires.

Embedded is understood to mean that the metal reinforcing element is in direct contact with the rubber composition over its entire surface.

The reinforced product according to the invention can be in the uncured state (before crosslinking of the rubber composition) or in the cured state (after crosslinking of the rubber composition). The reinforced product according to the invention is cured after contacting the reinforcing element with the rubber composition.

The reinforced product according to the invention comprises:
producing two layers of rubber composition;
sandwiching the reinforcing element between the two layers by depositing a reinforcing material between the two layers;
optionally curing the reinforced product according to the invention;
It can be manufactured by a process including.

Alternatively, the reinforced product according to the invention may be manufactured by depositing the reinforcing element on part of the layer and then folding the layer on itself to cover the reinforcing element and sandwiching it over its entire length or part of its length. I can do it.

The layer can be produced by calendering. During curing of the reinforced product according to the invention, the rubber composition is crosslinked.

If the reinforcing product according to the invention is intended to be used as reinforcement in a pneumatic tire, curing of the reinforcing product according to the invention is generally carried out during curing of the pneumatic tire.

(Finished or semi-finished products and tires)
Another subject of the invention is a finished or semi-finished product comprising a reinforcing product according to the invention. A finished or semi-finished product can be any article that includes a reinforced product. Examples include, but are not limited to, balls, conveyor belts, shoe soles, or pneumatic or non-pneumatic tires.

A pneumatic or non-pneumatic tire, which is another subject of the invention, has as an essential feature that it contains a reinforcing product according to the invention. The tire can be in an uncured state (before crosslinking of the rubber composition) or in a cured state (after crosslinking of the rubber composition). Generally, during tire manufacture, reinforcing products are deposited into the structure of the tire in an uncured state (ie, before crosslinking of the rubber composition) prior to the step of curing the tire.

The tire according to the invention comprises a reinforcing layer consisting of a reinforcing product according to the invention preferentially selected from carcass ply, crown ply, bead filler and combinations of these reinforcing layers. Furthermore, the rubber composition of the reinforced product according to the invention can be used as an inner layer of a pneumatic tire or a non-pneumatic tire, the inner layer being a layer of the tire that is not in contact with the ambient air and also not in contact with the inflation gas. It is. Such internal layers are, for example, crown foot layers, decoupling layers, edge rubbers and combinations of these internal layers. In this specification, "edge rubber" is understood to mean a layer that is arranged in the tire in direct contact with the edge of a reinforcing layer, the edge of a reinforcing element or another edge rubber.

The invention is particularly suitable for use in automobiles of the passenger car type, sport utility vehicles (SUVs), or two-wheeled vehicles (in particular motorcycles), or aircraft, as well as vans, large vehicles, i.e. underground trains, buses, large road transport vehicles (lorries, tractors). , trailers) or off-road vehicles, large agricultural vehicles or earth-moving machines, and other industrial vehicles.

The invention is therefore particularly intended for contacting a crown comprising a crown reinforcement formed from two crown plies of reinforcing elements and covered by a tread, and a rim each comprising a circumferential reinforcing element. A pneumatic or non-pneumatic tire comprising two beads and two sidewalls each extending radially inwardly, i.e. to the axial ends of the crown up to the beads, said tire further comprising: The present invention relates to a pneumatic or non-pneumatic tire comprising a carcass reinforcement extending from the bead through the sidewall to the crown, at least one of the two crown plies of the reinforcing element consisting of a reinforcing product according to the invention.

In another particular arrangement, the invention includes a crown reinforcement formed from two crown plies of reinforcing elements and contacting a crown covered with a tread and a rim each comprising a circumferential reinforcing element. A pneumatic or non-pneumatic tire comprising two beads and two sidewalls each extending radially inwardly, i.e. to the axial end of the crown up to the bead, said tire further comprising: The present invention relates to a pneumatic or non-pneumatic tire comprising a carcass reinforcement anchored to each of the beads and extending from the bead through the sidewall to the crown, at least the carcass reinforcement consisting of a reinforcing product according to the invention.

(Preparation of rubber composition)
The following tests involve sequential introduction of diene elastomer (epoxidized or non-oxidized), reinforcing filler, and various other components except the vulcanization system into an internal mixer with an initial vessel temperature of approximately 60°C (final Filling amount: approximately 70% by weight). Thermomechanical processing (non-productive stage) is then carried out in one step and lasts for a total of about 3-4 minutes until a "dropping" temperature of up to 165° C. is reached.

After the mixture thus obtained has been collected and cooled, the sulfur and accelerator (sulfenamide) are incorporated on a mixer (homofinisher) at 30°C and everything is heated for a suitable period of time (e.g. 5-12 minutes). during) mixing (production stage).

The composition thus obtained is then calendered in the form of plaques (2-3 mm thick) or thin rubber sheets and then subjected to a curing step at 150° C. for 15 minutes before physical or mechanical Measurements of physical characteristics are made.

(Measuring method)
(Adhesion test)
( Preparation of test piece )
The prepared rubber composition is used to make composites in the form of specimens according to the following protocol.

The metal/rubber composite used in this test was a block of rubber composition made by laminating two plaques measuring 200 mm x 4.5 mm (millimeters) and 3.5 mm thick before curing. The thickness of the block will be 7 mm. During the manufacture of this block, e.g. 15 reinforcements are captured between two uncured plaques and only a predetermined length of reinforcement, e.g. The remaining length of the reinforcement is isolated from the rubber composition (e.g. with a plastic or metal film) to prevent adhesion outside the defined contact zone. has been done. Each reinforcement passes through a block of rubber and a sufficient length (at least 5 cm, e.g. 5-10 cm) of at least one of its free ends is retained to allow subsequent tensile testing of the reinforcement. There is.

Each metal reinforcement consists of two threads of twisted steel with 0.7% carbon with a diameter of 30/100 mm, and the brass coating contains 63% copper.

The block containing 15 reinforcements is then placed in a suitable mold and cured at 150° C. for 15 minutes under a pressure of approximately 15 bar.

(Measurement of tear force)
Upon completion of curing and aging of the blocks described above, each reinforcement was pulled from the rubber block using a tensile tester according to the method described in standard ASTM D 2229-02, with a pull rate of 100 mm/min and therefore , adhesion is characterized by the force required to tear the reinforcement from the specimen at ambient temperature, where tear force represents the average of 15 measurements corresponding to 15 reinforcements of the composite.

The higher the force value, the higher the degree of adhesion between the cord and the rubber composition.

Tear force measurements are made after 21 days at t=0 in air at 77°C. The humidity of the air is uncontrolled and corresponds to the humidity of the outside air, ie 30% to 50%.

The results are expressed in terms of base 100, where the value 100 corresponds to specimens formed with the composition under consideration and the metal reinforcement described above. A value greater than 100 indicates an improved result, ie a tear force greater than the tear force of the specimen at t=0.

(Tensile test)
These tensile tests allow the elastic stress and properties at break of the rubber composition to be measured. The test was carried out according to the French standard NF T 46-002 of September 1988. Elongation at break (unit: %) is measured at 23°C.

Measurements of elongation at break are carried out at t=0 after 7 days at 77° C. in air and after 21 days at 77° C. in air. The humidity of the air is not controlled and corresponds to the humidity of the surrounding air, ie between 30% and 50%.

The results are expressed on a scale of 100, where the value 100 is assigned to the value of the elongation at break of the sample under consideration at t=0. A result greater than 100 indicates that the composition under consideration exhibits a greater elongation at break than the same composition at t=0.

(Rolling resistance meter)
The rolling resistance induced by the test composition is determined by the temperature of the energy recovered on the sixth rebound of the sample subjected to an initial energy of 60 °C, as described in the standard DIN 53-512 of April 2000. estimated by measuring energy loss at . This measurement is denoted P60 and is calculated as follows:
P60 (%) = 100 x (E0-E1)/E0
Here, E0 represents the initial energy and E1 represents the restored energy.

Measurements of loss at 60°C were carried out at t=0, after 7 days at 77°C in air, and after 21 days at 77°C in air. The humidity of the air is not controlled and corresponds to the humidity of the surrounding air, ie between 30% and 50%.

The results are expressed on a scale of 100, where the value 100 is assigned to the value of the loss at 60° C. of the sample under consideration at t=0. A result greater than 100 indicates that the composition under consideration exhibits greater losses at 60° C. than the same composition at t=0 and thus induces greater rolling resistance.

The results of the different tests are shown in Table 2.

Composition T1 is a prior art calendering composition as presented, for example, in document WO 2016/058943 and French Patent No. 2 981 298.

（１）天然ゴム（ペプタイズド）
（２）ＥＮＲ １：Ｇｕｔｈｒｉｅ Ｐｏｌｙｍｅｒ社製の２５ｍｏｌ％エポキシ化天然ゴム、ＥＮＲ－２５；ＥＮＲ ２：Ｍｕａｎｇ Ｍａｉ Ｇｕｔｈｒｉｅ社製の天然ゴムをエポキシ化することにより製造された１５％エポキシ化天然ゴム；
（３）ＡＳＴＭグレードＮ３２６（キャボット社製）；
（４）シリカ １６０ ＭＰ、Ｚｅｏｓｉｌ １１６５ＭＰ、Ｒｈｏｄｉａ社製；
（５）Ｏｃｔｅｏ、ＤｅｇｕｓｓａからＤｙｎａｓｙｌａｎ；
（６）酸化亜鉛（工業用）、Ｕｍｉｃｏｒｅ社製；
（７）ステアリン、Ｐｒｉｓｔｅｒｅｎｅ ４９３１、Ｕｎｉｑｅｍａから；
（８）Ｆｌｅｘｓｙｓ社製、Ｎ－（１，３－ジメチルブチル）－Ｎ’－フェニル－ｐ－フェニレンジアミン（Ｓａｎｔｏｆｌｅｘ ６－ＰＤ）；
（９）ＣＴＰ、Ｎ－（シクロヘキシルチオ）フタルイミド；Ｌａｎｘｅｓｓ社からＶｕｌｋａｌｅｎｔ Ｇの名で、又はＤｕｓｌｏ社からもＤｕｓｌｉｎ Ｐの名で販売されている；
（１０）Ｎ，Ｎ－ジシクロヘキシル－２－ベンゾチアゾールスルフェンアミド（Ｆｌｅｘｓｙｓ社のＳａｎｔｏｃｕｒｅ ＤＣＢＳ）；
（１１）Ｎ－シクロヘキシル－２－ベンゾチアゾールスルフェンアミド（Ｆｌｅｘｓｙｓ社のＳａｎｔｏｃｕｒｅ ＣＢＳ）；
（１２）ジフェニルグアニジン [Table 2]

(1) Natural rubber (peptized)
(2) ENR 1: 25 mol% epoxidized natural rubber manufactured by Guthrie Polymer, ENR-25; ENR 2: 15% epoxidized natural rubber manufactured by epoxidizing natural rubber manufactured by Muang Mai Guthrie;
(3) ASTM grade N326 (manufactured by Cabot);
(4) Silica 160 MP, Zeosil 1165 MP, manufactured by Rhodia;
(5) Dynasylan from Octeo, Degussa;
(6) Zinc oxide (industrial use), manufactured by Umicore;
(7) Stearine, Pristerene 4931, from Uniqema;
(8) Flexsys, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (Santoflex 6-PD);
(9) CTP, N-(cyclohexylthio)phthalimide; sold by Lanxess under the name Vulkalent G or also by Duslo under the name Duslin P;
(10) N,N-dicyclohexyl-2-benzothiazolesulfenamide (Santocure DCBS from Flexsys);
(11) N-cyclohexyl-2-benzothiazolesulfenamide (Santocure CBS from Flexsys);
(12) Diphenylguanidine

Claims (13)

A reinforced product based on at least one metal reinforcing element embedded in a rubber composition based on a crosslinking system comprising at least one epoxidized diene elastomer, a reinforcing filler and 1 to 2.5 phr sulfur, comprising:
A reinforced article, wherein the rubber composition comprises less than 0.5 phr of stearic acid or one of its derivatives and up to 2.5 phr of zinc oxide, and wherein the epoxidized diene elastomer is the main component in the rubber composition. . Claim wherein the vulcanization system further comprises a vulcanization accelerator used in a content of 0.1 to 6 phr, more preferentially 0.5 to 4 phr, very preferentially 0.5 to 2.5 phr. The reinforcing product described in 1. The reinforced product according to any one of claims 1 to 2, wherein the reinforcing filler contains silica as a main component. Reinforced product according to any one of claims 1 to 3, wherein the rubber composition further comprises a compound of the guanidine family, preferentially diphenylguanidine. Reinforcement according to claims 1 to 4, wherein the content of compounds of the guanidine group ranges from 0.5 to 3 phr, preferentially from 0.5 to 2.5 phr, and preferably from 0.5 to 2 phr. product. The epoxidized diene elastomer is preferably an epoxidized natural rubber, an epoxidized synthetic polyisoprene, an epoxidized polybutadiene with a content of cis-1,4 bonds preferentially greater than 90%, an epoxidized butadiene/styrene copolymer, and Reinforcement according to any one of claims 1 to 5, selected from the group consisting of mixtures of elastomers, preferentially selected from the group consisting of epoxidized natural rubber and epoxidized synthetic polyisoprene. product. The rubber composition further comprises a non-epoxy rubber selected from the group consisting of polybutadiene, natural rubber, synthetic polyisoprene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers, preferentially selected from natural rubber and synthetic polyisoprene. Reinforced product according to any one of claims 1 to 6, comprising a diene elastomer. Reinforced product according to any one of claims 1 to 6, wherein the rubber composition, when a sole elastomer, comprises one or more epoxidized diene elastomers. Claims 1-8 wherein the rubber composition is free of or contains less than 2 phr, preferentially less than 1 phr, in a preferred embodiment less than 0.5 phr, very preferentially less than 0.1 phr of cobalt salts. The reinforcing product described in any one of the above. Reinforced product according to any one of the preceding claims, wherein the rubber composition does not contain or contains less than 0.1 phr of stearic acid or one of its derivatives. The rubber composition includes an auxiliary agent selected from a coupling auxiliary agent for silica, an auxiliary agent for covering silica, and a mixture thereof, and the content of the auxiliary agent is 5% by weight based on the amount of silica. % to 20% by weight, preferentially from 6% to 18% by weight, or any one of claims 4 to 10 when these are dependent on claim 3. Reinforcement products listed in. A finished or semi-finished product comprising the reinforcing product according to any one of claims 1 to 11. A pneumatic or non-pneumatic tire comprising a reinforcing product according to any one of claims 1 to 11.