Use of an antioxidant to reduce and / or prevent the toxicity of a rubber composition

Abstract

The present invention relates to the use of at least one antioxidant in a rubber composition, said at least antioxidant comprising at least one oligomer and / or polymer comprising at least one diphenylamine repeating unit for reducing and / or preventing the toxicity of said rubber composition. Figure for abstract: No figure

Description

Title of the invention: Use of an antioxidant to reduce and / or prevent the toxicity of a rubber composition. Technical field

[0001] The present invention relates to the field of antioxidant additives used in rubber compositions, namely in elastomer compositions (macromolecular substances, natural or synthetic, possessing rubbery elasticity). The present invention relates in particular to the use of specific polymeric antioxidants in a rubber composition in order to reduce and / or prevent its toxicity. TECHNOLOGICAL BACKGROUND

[0002] The applications of rubber compositions cover a wide range of uses in everyday life, such as seals, pipes, in the automotive field (tires, car seat belts and various rubber parts: hoses, etc.), in the medical field, in clothing (shoe soles) and also in high-performance uses (aeronautics and offshore).

[0003] As is known, rubber compositions generally include one or more additives, including antioxidants.

[0004] Antioxidants are also used in a large number of applications and everyday objects, and, despite their relatively modest content in the material in which they are incorporated, their contribution is crucial with regard to the lifespan and preservation of the physicochemical and mechanical properties of these everyday objects. In the particular case of plastics, or even more specifically, rubbers used in pipes (parts under the hood, for example), electrical cables, or tires, their presence helps to preserve the mechanical properties of the materials by preventing, in particular, their hardening through oxidation in air or ozone (as is the case with tires subjected to the action of ozone generated by the heating of the air in contact with catalytic converters due to road traffic).

[0005] To date, aromatic amines, such as diphenylamine (DPA) or p-phenylenediamine (PPD) monomers, are very widely used in rubber hoses, cables, and tires. The latter family (PPD) is now a preferred additive due to its antioxidant and antiozonative properties, which are essential for tires subjected to these two aging phenomena. For example, the compound N,N'-Bis(l,4-dimethylpentyl)-p-phenylenediamine (hereinafter 77PD, CAS 3081-14-9) is commonly used for rubber coatings on electrical cables. Also, it is estimated that in 2009, 100,000 tonnes per year of N-(l,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (hereinafter 6PPD) were consumed in China for the manufacture of rubbers for all applications combined.

[0006] Unfortunately, recent studies show that the toxicological profile of standard antioxidants, such as those based on aromatic amines or diamines, is evolving negatively, drastically and alarmingly, given the established dangers to humans and the environment (carcinogenic, mutagenic, or toxic to reproduction, known as "CMR" status, aquatic / ecotoxic toxicity, bioaccumulation, and classification as a Persistent, Bioaccumulative, and Toxic substance, known as "PBT"). This trend is accelerating due to international regulatory agencies pushing for increasingly precise and intensive characterization of chemicals produced in very large volumes.As an example, the European Chemicals Agency (ECHA) reports the clear dangers of the main antioxidants belonging in particular to the family of diphenylamine (DPA) or p-phenylenediamine (PPD) monomers, which are used extensively in the chemical industries for fluids, plastics and rubbers.

[0007] In particular, standard antioxidants and their proven toxicity(s) are listed in Table 1 below: [Tables 1] Compound Name CAS No. Toxicity N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine 6PPD CAS 793-24-8 Impairs fertility or has adverse effects on the unborn child (reprotoxic), toxic to aquatic life with long-term effects (ecotoxic), is harmful if swallowed (acute toxicity) and may cause an allergic skin reaction (https: / / echa.europa.eu / fr / substance-information / - / substanceinfo / 100.011.222) N'-isopropyl-N'-phenyl-p-phenylenediamine IPPD CAS 101-72-4 Is very harmful to aquatic life with long-term effects (ecotoxic), is harmful if swallowed (acute toxicity) and may also cause an allergic skin reaction https: / / echa.europa.eu / fr / substance-information / - / substanceinfo / 100.002.700 N-cyclohexyl-N'-phenyl-p-phenylenediamine CPPD CAS 101-87-1 Is toxic to aquatic life with long-term effects (ecotoxic), and may also cause an allergic skin reaction https: / / echa.europa.eu / fr / substance-information / - / substanceinfo / 100.002.714 N,N'-diphenyl-p-phenylenediamine DPPD CAS 74-31-7 Is harmful to aquatic life with long-term effects (ecotoxic), and may also cause an allergic skin reaction. https: / / echa.europa.eu / fr / substance-information / - / substanceinfo / 100.000 .734 N,N'-Bis(1,4-dimethylpentyl)-p-phenylenediamine 77PD CAS 3081-14-9 Is very toxic to aquatic life with long-term effects (ecotoxic), is harmful if swallowed (acute toxicity) and may also cause an allergic skin reaction. https: / / echa.europa.eu / fr / substance-information / - / substanceinfo / 100.019 .433 Mixture of N,N-diphenylamine monomers Irganox® L57 1. CAS 68411-46-1 Is harmful to aquatic life with long-term effects (ecotoxic). https: / / echa.europa.eu / fr / substance-i Information / - / substanceinfo / 100.063 .733 Bis(nonylphenyl)amine Irganox® L67 CAS 36878-20-3 Is harmful to aquatic life with long-term effects (ecotoxic) https: / / echa.europa.eu / fr / substance-i Information / - / substanceinfo / 100.048 .393 N-phenyl-1-naphthylamine PAN-1 CAS 90-30-2 Is very toxic to aquatic life with long-term effects (ecotoxic), is harmful if swallowed (acute toxicity), may cause organ damage through prolonged or repeated exposure and may further cause an allergic skin reaction https: / / echa.europa.eu / fr / substance-information / - / substanceinfo / 100.001 .803 4,4'-methylene-bis-(2,6-di-tertbutylpheno 1) Ethanox ® 4702 or CAS 118-82-1 Under evaluation as an endocrine disruptor and as a persistent substance, bioac- . Cumulative and toxic MEDBP (substance PBT) https: / / echa.europa.eu / fr / substance-information / - / substanceinfo / 100.003.891

[0008] This toxicity of standard antioxidants has notably been confirmed by recent scientific research, such as that of Tian et al. Science, 2021, 371 (6525), 185-189 or that of W. Huang et al. Environ.Sci.Technol.Lett. 2021, 8, 381-385, which show that the main antioxidants used to date are toxic to humans and / or the environment.

[0009] The publication by Tian et al. concerns the effect of antioxidants on Pacific coho salmon (Oncorhynchus kisutch) (Northwest USA). The authors found that in this salmon, annual exposure to stormwater leads to unexplained acute mortality when adult salmon migrate to urban streams to spawn. By studying this phenomenon, they identified a highly toxic 6PPD transformation product, 6PPD-quinone, in the water. As mentioned above, 6PPD is a tire rubber antioxidant found worldwide. Therefore, this study demonstrates that 6PPD-derived oxidation products are even more toxic than 6PPD itself.In particular, retrospective analysis of road runoff and stormwater streams representative of the US West Coast revealed the widespread presence of 6PPD-quinone (<0.3 to 19 micrograms per liter) at toxic concentrations (median lethal concentration of 0.8 ± 0.16 micrograms per liter). This publication thus demonstrates that the compound 6PPD and its oxidation products are highly ecotoxic and that tire rubber residues dispersed in the environment pose a significant ecological threat.

[0010] The publication by W. Huang et al. further demonstrated that tire wear particles containing these toxic antioxidants are widespread in the environment, namely on roads, parking lots, and even inside cars and homes. These antioxidants include 6PPD, IPPD, CPPD, and DPPD. 6PPD-quinone, in particular, has been detected inside motor vehicles.

[0011] A publication by Zhang et al. Environ.Sci.Technol. 2021 (“p-Phenylenediamine Antioxidants in PM2.5: The Underestimated Urban Air Pollutants”) on air quality in major cities in China showed non-negligible traces of antioxidants commonly used in rubber compositions in fine particulate matter of urban atmospheric air, such as compounds 6PPD and 77PD, as well as the oxidation products IPPD-quinone and DPPD-quinone.

[0012] There is therefore a very urgent need in the state of the art to develop antioxidant, or even antiozonant, additives as alternatives to standard antioxidants such as those mentioned above in order to manufacture more virtuous rubber compositions.

[0013] In particular, there is a need in the prior art to develop alternative antioxidant additives for rubber composition which have both a satisfactory antioxidant effect, while also increasing the level of safety (reducing the danger to humans) and reducing the environmental impact of the rubber composition in which the antioxidant is incorporated, in the targeted fields of application (automotive, clothing, etc.). Description of the invention

[0014] In this context, the Applicant has focused on developing compounds that have antioxidant properties, while also preventing and / or reducing the toxicity of a rubber composition in which they are incorporated, compared to that of standard antioxidants, such as those mentioned above belonging in particular to the family of diphenylamine (DPA) or p-phenylenediamine (PPD) monomers.

[0015] As will be illustrated in the experimental section below, it has notably demonstrated, surprisingly and unexpectedly, that once oligomerized and / or polymerized, the toxicity of diphenylamine monomers is drastically reduced. They thus make it possible to form oligomers and / or polymers comprising at least one diphenylamine repeating unit exhibiting both antioxidant and even antiozonative properties, suitable for various applications of rubber compositions (tires, electrical cables, etc.), while being only slightly or not at all toxic to humans and / or the environment.

[0016] Indeed, the experimental tests below show that the antioxidants according to the invention, which were selected by the Applicant, were not chosen arbitrarily and exhibit a different technical effect (namely, they reduce / prevent / counteract the toxicity of a rubber composition) compared to other antioxidant compounds, particularly compared to diphenylamine (DPA) or p-phenylenediamine (PPD) monomers. Although the use of oligomeric and / or polymeric compounds comprising at least one diphenylamine repeating unit as antioxidant additives has already been considered in the prior art, to the Applicant's knowledge, no study has demonstrated their non-toxicity and, consequently, their usefulness in preventing and / or reducing, or even counteracting, the toxicity of a rubber composition. Summary of the invention

[0017] Thus, the present invention relates to the use of at least one antioxidant in a rubber composition, said at least antioxidant comprising at least one oligomer and / or polymer comprising at least one diphenylamine repeating unit of general formula (I): [Chem.l] R? wire ,z-., ix Xx II ® x'v“' fUi P: in which each of RI to RIO is independently chosen from a hydrogen atom, an alkyl group which is a saturated, linear or branched hydrocarbon group comprising from 1 to 24 carbon atoms and an aralkyl group which is an alkyl group as described above in which at least one of the carbon atoms is substituted by a monocyclic or polycyclic aromatic hydrocarbon aryl group comprising from 5 to 14 carbon atoms, to reduce and / or prevent the toxicity of said rubber composition.

[0018] Of course, the different features, variants and embodiments of the invention can be combined with each other in various ways insofar as they are not incompatible or mutually exclusive.

[0019] In the present invention, unless otherwise specified, the term "include" and its derivatives shall be understood as non-limiting and not excluding the presence of other components or steps. In certain particular embodiments, the term "include" may be understood as "consisting essentially of" or "being made up of".

[0020] Unless otherwise specified, the intervals mentioned in the present invention Prices include terminals. DETAILED DESCRIPTION

[0021] The present invention thus relates to the use of at least one antioxidant in a rubber composition, said at least antioxidant comprising at least one oligomer and / or polymer comprising at least one diphenylamine repeating unit of general formula (I): [Chem.l] in which each of RI to RIO is chosen independently from: a hydrogen atom, an alkyl group which is a saturated hydrocarbon group, linear or branched, comprising from 1 to 24 carbon atoms and an aralkyl group which is an alkyl group as described above in which at least one of the carbon atoms is substituted by a monocyclic or polycyclic aromatic hydrocarbon aryl group comprising 5 to 14 carbon atoms, to reduce and / or prevent the toxicity of said rubber-based composition.

[0022] By antioxidant, we mean specialty chemical additives which serve to interrupt the degradation process linked to oxidation in compositions in which they are incorporated, in the present case rubber compositions.

[0023] According to the invention, the "toxicity" of a substance and / or composition means that said substance and / or composition exhibits at least one, preferably at least two, in particular at least three and typically at least four, as well as at least five, at least six, or even all of the following toxicities: - reproductive toxicity, which corresponds to impaired fertility or impairment of the mammal / unborn living being, - mutagenicity, which is the propensity of a substance to cause genetic mutations, - acute toxicity, which is the toxicity induced, within a short period of time (e.g., 24 hours), by the administration or contact (topical application) of a single (possibly massive) dose or several doses acquired within this period of time of a toxic product or mixture (natural or chemical), - ecotoxicity which is the set of imbalances or nuisances caused by an industrial activity or the introduction of a body, a foreign product in a natural environment generally linked to human activity; - Neurotoxicity, which is the ability of a substance or compound to induce adverse effects in the nervous system of a mammal / living being, such as humans or planarians, - the carcinogenic nature, which is the propensity of a substance to cause / provoke the onset of cancer or contributing to its aggravation, - toxicity on the synthesis, degradation, transport and mode of action of hormones, as is the case with endocrine disruptors (indirect toxicity via the physiological changes they cause).

[0024] A compound having a CMR character (carcinogenic, mutagenic, or toxic to reproduction character) thus presents various toxicities.

[0025] According to a feature of the invention, toxicity thus includes one or more of the following toxicities: neurotoxicity, reprotoxicity, mutagenicity, acute toxicity, carcinogenicity, toxicity on the synthesis, degradation, transport and mode of action of hormones and ecotoxicity.

[0026] “By reducing” the toxicity of a rubber composition, it is understood that said at less antioxidant according to the invention (namely comprising at least one oligomer and / or polymer comprising at least one diphenylamine repeating unit of general formula (I)) is suitable and / or configured to decrease the toxicity of a rubber composition in which it is included, namely by its presence, in particular compared to other possible standard antioxidant compounds which are generally toxic, that said less antioxidant according to the invention comprising at least one oligomer and / or polymer comprising at least one diphenylamine repeating unit of general formula (I) makes it possible to lower / decrease the toxicity of a rubber composition and to obtain a non-toxic rubber composition or at least one with reduced toxicity.

[0027] “By preventing” the toxicity of a rubber composition, we mean said at The less antioxidant compound according to the invention, comprising at least one oligomer and / or polymer including at least one diphenylamine repeating unit of general formula (I), prevents the rubber composition from being considered toxic and / or prevents the appearance of toxic symptoms in a mammal or any other living being, such as a human or an animal, that comes into contact with said rubber composition. For example, neurotoxic symptoms may affect the central nervous system (CNS) and present the following effects: headaches, loss of appetite, drowsiness, mood and personality disorders, cognitive impairments (learning and concentration difficulties), or affect the peripheral nervous system (PNS) and present the following effects: motor impairments such as weakness, tremors, incoordination, convulsions, etc.or sensory impairments, such as decreased hearing, color vision, tinnitus, loss of balance, etc.; these effects may be reversible or irreversible depending on the degree of acute or chronic exposure of the mammal. For example, symptoms of acute toxicity may include skin irritation, allergic skin reaction, vomiting, etc.

[0028] In general, said at least antioxidant according to the invention (namely comprising at least one oligomer and / or polymer comprising at least one diphenylamine repeating unit of general formula (I)) is suitable for and / or configured to reduce and / or prevent the toxicity of a rubber composition at the various stages of the life of said rubber composition, namely its implementation, its use and its end of life including spreading in the environment (such as particles, or wear of a tire made from said composition).

[0029] According to a particular embodiment, said oligomer and / or polymer comprising at least one diphenylamine repeating unit of general formula (I) may also comprise at least one phenyl α-naphthylamine repeating unit of general formula (II): [Chem. 2] in which each of R11 to R22 is chosen independently from: a hydrogen atom and an alkyl group which is a saturated hydrocarbon group, linear or branched, comprising from 1 to 24 carbon atoms.

[0030] In the present invention, "polymer" of at least one diphenylamine and optionally at least one phenyl a-naphthylamine means a compound comprising the repetition of at least two diphenylamine motifs with optionally at least one phenyl a-naphthylamine motif.

[0031] In the present invention, the term "oligomer" of at least one diphenylamine and optionally at least one phenyl α-naphthylamine refers to a polymer of at least one diphenylamine and optionally at least one phenyl α-naphthylamine comprising between 2 and 15 repeating units, or a mixture of such compounds. It may, in particular, be a dimer, trimer, tetramer, pentamer, hexamer, heptamer, octamer, nonamer, decamer, and / or any mixture of such compounds. Preferably, the oligomer contains (in relative %) at least 70%, preferably 80%, and in particular 90% by mass of the dimer, trimer, tetramer, pentamer, or a mixture of such compounds.

[0032] By "repeat motif" diphenylamine or phenyl α-naphthylamine, we mean the fact that, in the final structure of the oligomer or polymer obtained according to the invention, there is at least one diphenylamine motif and at least one phenyl motif α-naphthylamine, or at least two diphenylamine motifs with possibly at least one phenyl α-naphthylamine motif.

[0033] The diphenylamine and phenyl α-naphthylamine repeating units can be positioned in any way relative to each other within the structure of the polymer or oligomer according to the invention. Thus, the polymer or oligomer may comprise, at least in a portion of its structure, a regular alternation of diphenylamine and phenyl α-naphthylamine repeating units. It may comprise, at least in a portion of its structure, a random distribution of diphenylamine and phenyl α-naphthylamine repeating units. Finally, it may comprise, in at least a portion of its structure, a block comprising a single type of diphenylamine or phenyl α-naphthylamine repeating unit.

[0034] In one embodiment, the polymer and / or oligomer according to the invention comprises in its structure only diphenylamine and phenyl α-naphthylamine repeating units. In another embodiment, the polymer and / or oligomer according to the invention comprises in its structure only diphenylamine repeating units.

[0035] By "diphenylamine" is meant a compound of formula (I): [Chem.l] K! ^4 in which each of RI to RIO is chosen independently from: a hydrogen atom, an alkyl group (which is a saturated, linear or branched hydrocarbon group comprising from 1 to 24 carbon atoms) and an aralkyl group (which is an alkyl group as described above in which at least one of the carbon atoms is substituted by a monocyclic or polycyclic aromatic hydrocarbon aryl group comprising from 5 to 14 carbon atoms).

[0036] In one embodiment, at least one diphenylamine of formula (I) is an alkylated diphenylamine, that is, at least one of R1 to R10 is an alkyl or aralkyl group. In another embodiment, at least one of R1 to R5 is an alkyl or aralkyl group, and at least one of R6 to R10 is an alkyl or aralkyl group.

[0037] In the present invention, "alkyl" refers to a saturated, linear, branched, or cyclic hydrocarbon group comprising from 1 to 24 carbon atoms. Preferably, an alkyl group comprises from 1 to 12 carbon atoms. Examples of alkyl groups include, in particular, the methyl group, the ethyl group, the n-propyl group, the isopropyl group, n-butyl group, tert-butyl group, isobutyl group, n-pentyl group, isopentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, tert-octyl group, iso-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, and isododecyl group. In a particular embodiment, an alkyl group is selected from the group consisting of the tert-butyl and tert-octyl groups, or the n-nonyl group (nC9), and is more specifically selected from the group consisting of the tert-butyl and tert-octyl groups.

[0038] In the present invention, "aralkyl" refers to an alkyl group in which at least one of the carbon atoms is substituted by an aryl group. Examples of aralkyl groups include, in particular, 1-methyl-1-phenylethyl, a styryl (C6H5-CH=CH-) or methylstyryl group.

[0039] In the present invention, the term "aryl group" refers to a monocyclic or polycyclic aromatic hydrocarbon group. Each aromatic or poly-aromatic ring comprises 5 to 14 atoms. Examples of aryl groups include, in particular, the phenyl group.

[0040] In one embodiment, the diphenylamine of formula (I) is chosen from the group consisting of N,N-diphenylamine, N,N-di-(p-tert-butylphenyl)amine, N,N-di-(p-tert-octylphenyl)amine, N-(p-tert-butylphenyl)-N-phenylamine, N-(p-tert-octylphenyl)-N-phenylamine, N-(p-tert-butylphenyl)-N-(p-tert-octylphenyl)amine and any mixture thereof.

[0041] In a particular embodiment, the polymer or oligomer according to the present invention comprises only diphenylamine motifs. The oligomer comprising at least one diphenylamine repeating motif of general formula (I) according to the invention can thus be a dimer, a trimer, a tetramer, a pentamer of one or more of these diphenylamines of formula (I) described above and correspond, by way of example, to a dimer or a trimer of di-(p-tert-octylphenyl)amine (DODPA).

[0042] The diphenylamines according to the invention can be presented individually, or in mixtures with each other. For example, they can be presented in the form of a mixture of N,N-diphenylamine, N,N-di-(p-tert-butylphenyl)amine, N,N-di-(p-tert-octylphenyl)amine, N-(p-tert-butylphenyl)-N-phenylamine, N-(p-tert-octylphenyl)-N-phenylamine and N-(p-tert-butylphenyl)-N-(p-tert-octylphenyl)amine.

[0043] According to the present invention, phenyl α-naphthylamine refers to a compound of formula (II): [Chem.2] in which each of R11 to R22 is chosen independently from: a hydrogen atom and an alkyl group which is a saturated hydrocarbon group, linear or branched, comprising from 1 to 24 carbon atoms.

[0044] In one embodiment, at least one of R11 to R22 is an alkyl group. In another embodiment, only one of R11 to R22 is an alkyl group, in particular a tert-octyl group.

[0045] In a particular embodiment, phenyl a-naphthylamine is N-(4-tert-octylphenyl)-l-naphthylamine, CAS number 4572-51-4 (OPAN).

[0046] In one embodiment of the invention, at least one diphenylamine is in the form of a mixture of N,N-diphenylamine, N,N-di-(p-tert-butylphenyl)amine, N,N-di-(p-tert-octylphenyl)amine, N-(p-tert-butylphenyl)-N-phenylamine, N-(p-tert-octylphenyl)-N-phenylamine and N-(p-tert-butylphenyl)-N-(p-tert-octylphenyl)amine, and at least one phenyl α-naphthylamine is N-(4-tert-octylphenyl)-α-naphthylamine (OPAN).

[0047] In another embodiment of the invention, at least one diphenylamine is di-(p-tert-octylphenyl)amine (DODPA) and at least one phenyl α-naphthylamine is N-(4-tert-octylphenyl)-1-naphthylamine (OPAN). The oligomer forming the antioxidant according to the invention can thus correspond to a 2DODPA / 1OPAN, 1DODPA / 2OPAN, or 3DODPA trimer. According to one embodiment, said at least one oligomer can correspond to a mixture of trimers, such as a mixture of 2DODPA / 1OPAN, 1DODPA / 2OPAN, and 3DODPA. In particular, within this mixture, the 2DODPA / 1OPAN oligomer is the predominant component. In general, said at least oligomer comprises a mixture of trimers (such as 2DODPA / 1OPAN, 1DODPA / 2OPAN, 3DODPA), tetramers, pentamers and hexamers.

[0048] The relative mass proportions of the two types of diphenylamine and phenyl α-naphthylamine motifs within the polymer or oligomer can vary to a wide extent from 0 / 100 to 100 / 0. Preferably, the relative mass proportion diphenylamine / phenyl α-naphthylamine is between 100 / 0 and 10 / 90, in particular between 100 / 0 and 30 / 70 (such as 50 / 50 or 80 / 20), in particular between 100 / 0 and 90 / 10 and typically between 100 / 0 and 95 / 5.

[0049] The polymer or oligomer according to the present invention forming said at least anti The oxidant according to the invention can, in particular, be prepared according to the process described in patent application FR 2010199 filed by the Applicant, namely in a continuous reactor. Those skilled in the art can adjust the quantities of diphenylamine and phenyl α-naphthylamine to be introduced into the reactor, depending in particular on the desired structure of the oligomer or polymer to be synthesized and the required thermal characteristics. The polymer or oligomer according to the present invention, forming said antioxidant according to the invention, can also, in particular, be prepared according to the process described in document US 2019 / 0127526 or document WO 2008 / 022028.

[0050] For the present invention, the Applicant has demonstrated the non-toxicity of said at least antioxidant comprising at least one oligomer and / or a polymer comprising at least one diphenylamine repeat motif of formula (I) and optionally at least one phenyl a-naphthylamine repeat motif of formula (II) according to the invention by QSAR modeling tests for neurotoxicity, for reprotoxicity, for mutagenicity and carcinogenicity.

[0051] In particular, the oligomer and / or polymer comprising at least one diphenylamine repeating unit of formula (I) and optionally at least one phenyl α-naphthylamine repeating unit of formula (II) has a QSAR value for measuring each of the following toxicities: neurotoxicity (neurostotoxic QSAR), reprotoxicity (reprotoxic QSAR), mutagenicity (mutagenic QSAR) and carcinogenicity (carcinogenic QSAR), corresponding to a statistical threshold value (%) subtracted from a delta of at least 30%, said statistical threshold value being determined, for each of said toxicities, by QSAR (quantitative structure-activity relationship) modeling according to the method described below in the experimental part,

[0052] According to the invention, "a delta of at least 30%" for QSAR modeling includes the following values ​​and all intervals between these values: 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 55; 60; 65; 70; 75; 80; 85; 90; 91; 92; 93; 94; 95; 96; 97; 98; 99; 100 (this range of at least 30% is to be adapted for each of the toxicities).

[0053] According to one embodiment, the statistical threshold value of the neurotoxic QSAR in percentage is typically 55%.

[0054] Preferably, the delta for the measurement of the neurotoxic QSAR is at least 45%, advantageously at least 55% and typically at least 53%.

[0055] In general, the oligomer and / or polymer comprising at least one diphenylamine repeating unit of formula (I) and optionally at least one phenyl α-naphthylamine repeating unit of formula (II) has a percentage value (%) by QSAR modeling less than or equal to 10%, preferably less than or equal to 5% and ty prick less than or equal to 2% for the measurement of neurotoxicity (neurotoxic QSAR).

[0056] According to the invention, a value less than or equal to 10% for neurotoxic QSAR modeling includes the following values ​​and all intervals between these values: 10; 9; 8; 7; 6; 5; 4; 3; 2; 1; 0.9; 0.8; 0.70; 0.69; 0.68; 0.67; 0.66; 0.65; 0.64; 0.63; 0.62; 0.61; 0.60; 0.59; 0.58; 0.57; 0.56; 0.55; 0.54; 0.53; 0.52; 0.51; 0.50; 0.49; 0.48; 0.47; 0.46; 0.45; 0.44; 0.42; 0.40; 0.38; 0.36; 0.34; 0.32; 0.30; 0.28; 0.26; 0.24; 0.22; 0.20; 0.18; 0.16; 0.14; 0.12; 0.10; 0.09; 0.08; 0.07; 0.06; 0.005; 0.04; 0.03; 0.02; 0.01; 0.00.

[0057] According to another embodiment, the statistical threshold value QSAR reprotoxic in percentage is typically 90%.

[0058] Preferably, the delta for the measurement of the reprotoxic QSAR is at least 41%, advantageously at least 43% and typically at least 46%.

[0059] In general, the oligomer and / or polymer comprising at least one diphenylamine repeat motif of formula (I) and optionally at least one phenyl α-naphthylamine repeat motif of formula (II) has a percentage value (%) by QSAR modeling less than or equal to 65%, preferably less than or equal to 50% and typically less than or equal to 45% for the reprotoxicity measurement (repro toxic QSAR).

[0060] According to the invention, a value less than or equal to 65% for reprotoxic QSAR modeling includes the following values ​​and all intervals between these values: 65; 64; 63; 62; 61; 60; 59; 58; 57; 56; 55; 54; 53; 52; 51; 50; 49; 48; 47; 46; 45; 44; 43; 42; 41; 40; 39; 38; 37; 36; 35; 34; 33; 32; 31; 30; 29; 28; 27; 26; 25; 24; 23; 22; 21; 20; 15; 10; 5; 3; 1; 0.50; 0.49; 0.48; 0.47; 0.46; 0.45; 0.44; 0.42; 0.40; 0.38; 0.36; 0.34; 0.32; 0.30; 0.28; 0.26; 0.24; 0.22; 0.20; 0.18; 0.16; 0.14; 0.12; 0.10; 0.09; 0.08; 0.07; 0.06; 0.005; 0.04; 0.03; 0.02; 0.01; 0.00.

[0061] According to another embodiment, the statistical threshold value (mutagenic QSAR in percentage) is typically 58%.

[0062] Preferably, the delta for the measurement of the mutagenic QSAR is at least 48%, advantageously at least 53% and typically at least 56%.

[0063] Generally, the oligomer and / or polymer comprising at least one diphenylamine repeat motif of formula (I) and optionally at least one phenyl α-naphthylamine repeat motif of formula (II) has a percentage (%) value by QSAR modeling less than or equal to 10%, preferably less than or equal to 5% and typically less than or equal to 2% for the mutagenicity measurement (mutagenic QSAR).

[0064] According to the invention, a value less than or equal to 10% for QSAR modeling Mutagenic includes the following values ​​and all intervals between them: 10; 9; 8; 7; 6; 5; 4; 3; 2; 1; 0.9; 0.8; 0.70; 0.69; 0.68; 0.67; 0.66; 0.65; 0.64; 0.63; 0.62; 0.61; 0.60; 0.59; 0.58; 0.57; 0.56; 0.55; 0.54; 0.53; 0.52; 0.51; 0.50; 0.49 ; 0.48 ; 0.47 ; 0.46 ; 0.45 ; 0.44 ; 0.42 ; 0.40 ; 0.38 ; 0.36 ; 0.34 ; 0.32 ; 0.30 ; 0.28 ; 0.26; 0.24; 0.22; 0.20; 0.18; 0.16; 0.14; 0.12; 0.10; 0.09; 0.08; 0.07; 0.06; 0.005; 0.04; 0.03; 0.02; 0.01; 0.00.

[0065] According to another embodiment, the statistical threshold value QSAR carcinogenic as a percentage is typically 85%.

[0066] Preferably, the delta for the measurement of the carcinogenic QSAR is at least 77%, advantageously at least 82% and typically at least 85%.

[0067] In general, the oligomer and / or polymer comprising at least one diphenylamine repeat motif of formula (I) and optionally at least one phenyl α-naphthylamine repeat motif of formula (II) has a percentage value (%) by QSAR modeling less than or equal to 10%, preferably less than or equal to 5% and typically less than or equal to 2% for the carcinogenic character measurement (carcinogenic QSAR).

[0068] According to the invention, a value less than or equal to 10% for carcinogenic QSAR modeling includes the following values ​​and all intervals between these values: 10; 9; 8; 7; 6; 5; 4; 3; 2; 1; 0.9; 0.8; 0.70; 0.69; 0.68; 0.67; 0.66; 0.65; 0.64; 0.63; 0.62; 0.61; 0.60; 0.59; 0.58; 0.57; 0.56; 0.55; 0.54; 0.53; 0.52; 0.51; 0.50; 0.49 ; 0.48 ; 0.47 ; 0.46 ; 0.45 ; 0.44 ; 0.42 ; 0.40 ; 0.38 ; 0.36 ; 0.34 ; 0.32 ; 0.30 ; 0.28 ; 0.26; 0.24; 0.22; 0.20; 0.18; 0.16; 0.14; 0.12; 0.10; 0.09; 0.08; 0.07; 0.06; 0.005; 0.04; 0.03; 0.02; 0.01; 0.00.

[0069] The term "rubber composition" generally refers to an elastomeric composition comprising, by definition, macromolecular substances, natural or synthetic, possessing rubbery elasticity. In particular, elastomer is understood to be a polymer exhibiting elastic properties obtained after cross-linking.

[0070] “Rubber / elastomer” means an elastic, impermeable substance and resistant obtained by coagulation of the latex of certain plants, trees or lianas of the equatorial forest, or prepared synthetically, by polymerization of various unsaturated hydrocarbons.

[0071] The current classification consists of separating rubbers into three main categories (the abbreviations used are those recommended by ISO 1629 of 1995): - general purpose rubbers, which are represented by natural rubber (NR) and synthetic polyisoprene (IR), styrene butadiene copolymers (SBR) and polybutadienes (BR); - special rubbers, which are co- or terpolymers of ethylene propylene and diene (EPM and EPDM), isobutylene isoprene copolymers, chlorinated or brominated (IIR, BIIR, CIIR), butadiene acrylonitrile copolymers (NBR), and polychlorinated polyprenes (CR); - very special rubbers, which include silicone rubbers (VMQ, FVMQ), fluorinated elastomers (FKM), chlorinated and chlorosulfonated polyethylenes (CM, CSM), polyacrylates (ACM), ethylene vinyl acetate copolymers (EVM) and ethylene methyl acrylate (AEM), hydrogenated nitrile rubbers (HNBR) and epichlorohydrin rubbers (CO, ECO, GECO), malleable polyurethanes (AU, EU). Thermoplastic elastomers, which form a separate category, can be added to this classification. Indeed, unlike the rubbers mentioned previously, these elastomers do not need to be vulcanized and are processed like thermoplastics.

[0072] As is known, natural rubber (NR) is obtained from the coagulation of latex from several plants, primarily the rubber tree, Hevea brasiliensis, of the Euphorbiaceae family, native to the Amazon. Collection is carried out by making incisions in the bark of the trunks so that the latex, flowing from the laticiferous canals, collects in cups placed directly below. The harvested latex is transferred to containers, filtered, and can then be stabilized with ammonia (precipitation of flakes) and then pressed to reduce its water content, or alternatively coagulated in a more or less controlled manner and dried by the smoke of a fire (the tars prevent putrefaction) to obtain rubber balls.

[0073] By way of example, synthetic rubber can be manufactured from the polymerization of various monomers, including isoprene (2-methyl-1,3-butadiene), 1,3-butadiene, chloroprene (2-chloro-1,3-butadiene), and isobutylene (methylpropene) with a small percentage of isoprene for crosslinking. These and other monomers can be blended in various desirable proportions to be copolymerized for a wide range of physical, mechanical, and chemical properties. The monomers can be produced in pure form, and the addition of impurities or additives can be controlled by design to provide optimal properties. The polymerization of pure monomers can be more precisely controlled to give a desired ratio of cis and trans double bonds.Other well-known rubber compositions include butadiene-acrylonitrile, also called "nitrile rubbers" (NBR, in English: nitrile butadiene rubber) or AEM for ethylene acrylic rubber in English.

[0074] In the present invention, a rubber composition or an elastomeric composition (synonym) means a composition comprising predominantly rubber, namely a composition comprising, by mass, at least 60% of preferably at least 70%, in particular at least 80% and typically at least 90% rubber.

[0075] Generally, said rubber composition and / or said at least antioxidant additive does not substantially comprise, preferably does not comprise, diphenylamine monomers (DPA) or p-phenylenediamine monomers (PPD) or any other standard antioxidant (toxic and / or ecotoxic) mentioned above in the prior art description, whatever it may be. In certain embodiments, the rubber composition used according to the invention or the antioxidant used according to the invention does not substantially comprise, preferably does not comprise, any antioxidant additive other than the oligomer and / or polymer comprising at least one diphenylamine repeating unit of formula (I) and optionally at least one phenyl α-naphthylamine repeating unit of formula (II) according to the invention.

[0076] In general, the antioxidant additive according to the invention represents, by mass, relative to the total mass of the antioxidants present in the rubber-based composition, from 50% to 100%, preferably from 80% to 100%, and in particular from 90% to 100% and typically 100%. According to the invention, "50% to 100%" means the following values ​​or any interval between these values: 50; 55; 60; 65; 70; 75; 80; 85; 90; 95; 100.

[0077] Said at least one antioxidant agent and generally said at least one oligomer and / or polymer comprising at least one diphenylamine repeating unit of formula (I) and optionally at least one phenyl α-naphthylamine repeating unit of formula (II) is present in the rubber-based composition used in the present invention in an amount such as those conventionally used in the art. For example, they may be used in an amount of 0.1 to 10% by weight, preferably 0.5 to 5% by weight, typically 1 to 4% relative to the total weight of said rubber composition.

[0078] The rubber composition may also include other additives, such as mineral solid fillers for enhancing mechanical properties, carbon black, plasticizers, vulcanizing agents (such as elemental sulfur or polythiols), vulcanization accelerators, crosslinking retarders, silanes, and other agents capable of increasing the degree of crosslinking, etc. These other additives will not be described in further detail below because their composition and conditions of use (mass content, etc.) are known to those skilled in the art, depending on the intended uses of the rubber-based composition.

[0079] The present invention can also be applied to a method for preserving the physicochemical and mechanical properties of a rubber-based composition comprising: - prepare said rubber composition, which preferably does not include diphenylamine (DPA) or p-phenylenediamine (PPD) monomers, - incorporate into said rubber-based composition an effective amount of at least one antioxidant comprising an oligomer and / or polymer comprising at least one diphenylamine repeating unit of formula (I) as defined above and optionally at least one phenyl a-naphthylamine repeating unit of formula (II) as defined above, said at least antioxidant being capable of reducing and / or preventing the toxicity of said rubber-based composition.

[0080] Of course, the various embodiments described above for the use of said at least antioxidant to prevent and / or reduce the toxicity of a rubber-based composition also apply to this process and will not be repeated below.

[0081] According to the invention, unless otherwise specified, the percentages indicated in this application are percentages by mass.

[0082] In the present invention, the term "approximately" a value V designates an interval between 0.9xV and 1.1xV. In certain embodiments, it designates an interval between 0.95xV and 1.05xV, in particular an interval between 0.99xV and 1.01xV. EXAMPLES Example 1: Toxicity Study

[0083] The oligomers and / or polymers comprising at least one diphenylamine repeat motif of formula (I) and optionally at least one phenyl a-naphthylamine repeat motif of formula (II) according to the invention have been studied and compared to other standard antioxidant compounds, in terms of QSAR modeling for neurotoxicity, reprotoxicity, mutagenicity and carcinogenicity. QSAR modeling protocol

[0084] The toxicity levels of different compounds used according to the invention and other standard antioxidants were evaluated by QSAR (quantitative structure-activity relationship) modeling. Selection of training and validation games

[0085] A set of test molecules was defined with chemical structures compiled from several publicly available sources such as: HSBD (Hazardous Substances Data Bank), EPA (US Environmental Protection Agency), PECHA (European Chemicals Agency) and NTP (National Toxicology Program). Approximately 34,000 molecules were selected for this project, including: 3,245 compounds classified as neurotoxic, 12,609 compounds classified as reprotoxic, 4,084 compounds classified as mutagenic, and 12,158 compounds classified as carcinogenic compounds and 1953 compounds, called non-toxic, classified as neither neurotoxic, nor reprotoxic, nor mutagenic, nor carcinogenic.

[0086] From this set of test molecules, two sets of molecules were defined: a training set and a validation set. To do this, the "leave one out" method was used. The set of test molecules was divided into two sets, one containing 90% of the test molecules and forming the training set; and the other, containing the remaining 10% of the test molecules, forming the validation set. QSAR model performance

[0087] A generalized linear model (GLM) method was chosen to implement a quantitative structure-activity relationship (QSAR) approach. From the training set, GLM models were trained separately to discriminate chemical structures (i) between neurotoxic and non-neurotoxic compounds, (ii) between reprotoxic and non-reprotoxic compounds, (iii) between mutagenic and non-mutagenic compounds, and (iv) between carcinogenic and non-carcinogenic compounds. This approach resulted in four GLM models with 328, 313, 327, and 330 significant descriptors, respectively, within the neurotoxic, reprotoxic, mutagenic, and carcinogenic training sets. During training, the performance of the QSAR models was measured by ROC (Receiver Operator Characteristic) curves and gave rise to area under the curve (AUC) values ​​of 0.8831 for the prediction of neurotoxicity, 0.7967 for the prediction of reprotoxicity, 0.8444 for the prediction of mutagenicity and 0.8333 for the prediction of carcinogenicity.

[0088] To validate the robustness of the QSAR models, they were then used to predict (i) the neurotoxicity categories of the compounds in the validation set (i.e. the categorization of neurotoxic / non-neurotoxic), (ii) the reprotoxicity categories of the compounds in the validation set (i.e. the categorization of reprotoxic / non-reprotoxic), (iii) the mutagenicity categories of the compounds in the validation set (i.e. the categorization of mutagenic and non-mutagenic) and (iv) the carcinogenicity categories of the compounds in the validation set (i.e. the categorization of carcinogenic and non-carcinogenic). During validation, the performance of the QSAR models was measured by area under the curve (AUC) values ​​and provided significant values ​​of 0.76 and above for the prediction of neurotoxicity, mutagenicity and carcinogenicity and provided significant values ​​of 0.70 and above for the prediction of reprotoxicity.

[0089] GLM-based QSAR models were then used to study the compounds according to the invention. Interpretation of the results

[0090] Once the model has been built on the training set and then validated with the validation set, it mathematically determines a threshold value on a statistical basis. statistic expressed as a percentage.

[0091] The statistical threshold values ​​QSAR for the different toxicities tested are illustrated in Table 2 below: [Tables 2] Non-toxic and moderately toxic molecules (%) Toxic molecules (%) QSAR Neurotoxic <55% >55% QSAR Reprotoxic <90% >90% QSAR Mutagenic <58% >58% QSAR Carcinogenic <85% >85%

[0092] This statistical threshold is a first draft allowing the distinction between non-toxic, moderately toxic, and toxic molecules. However, it does not allow the complete exclusion of toxic molecules from non-toxic molecules (i.e., the margin of error on the probability of toxicity risk). The Applicant thus refined its research and determined that a reduction of the statistical threshold by a delta of 30% for each model (neurotoxic QSAR, reprotoxic QSAR, etc.) reliably guaranteed the toxicity of the tested molecules. Indeed, this new threshold (statistical threshold -30%) makes it possible to indisputably separate moderately toxic and residual toxic molecules from non-toxic molecules. Furthermore, an intermediate range (non-zero probability of toxicity) including moderately toxic and / or toxic residual molecules was established in order to create a more precise classification.

[0093] The classification refined by the Applicant is illustrated in Table 3 below. [Tables 3] Slightly toxic (%) Moderately toxic (intermediate range) (%) Highly toxic (%) Neurotoxic QSAR <25 25 < QSAR < 55 55 < QSAR < 100 Reprotoxic QSAR <60 60 < QSAR < 90 90 < QSAR < 100 Mutagenic QSAR <28 28 < QSAR < 58 58 < QSAR < 100 Carcinogenic QSAR <55 55 < QSAR < 85 85 < QSAR < 100

[0094] The compounds tested are numbered as follows (Table 4 below): [Tables 4] Ex Chemical Name CAS No. Developed Formula A Dimer of p,p'-dioctyldiphenylamine or DODPA dimer 35972- 72-6 %a ,-sXx k J AJ y ?\ / \ T \ / B Trimer: 2DODPA / 1 OPAN: -x • ''jX '•s---*' C Oligomeric amine mixture based on DODPA and OPAN (i.e.: of which 0-5% monomer, 25-30% dimer A, 20-25% trimer B, 15-20% tetramer) obtained according to the method described in patent applications FR 2 924 122 and WO 2009 / 071857 1 p,p'-dioctyldiphenylamine ( DODPA) 15721- 78-5 -'■■'Jx. XX ' XX 2 N - (4-tert-octy Ipheny 1) -1 -naphthy lamine (OPAN) 4572-5 1-4 yx 3 4,4'-Methylene-bis-(2,6-di-tert-butylphenol) (MEDBP) 118-82- 1 4 Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphe nyl)propanoate Irganox® L107 2082-7 9-3 RI = nCi8H37 5 Octyl 3-[4-hydroxy-3,5-bis(2-methyl-2-propanyl)phenyl]propanoate 125643 -61-0 - RI = nC JI yy 17 6 ​​2-ethylhexyl 3-[4-hydroxy-3,5-bis(2-methyl-2-propanyl)phenyl]propanoate Irganox® L145 144429 -84-5 1 Rl = 2Ethylhexyl 7 1,6-Hexanediyl bis{3-[4-hydroxy-3,5-bis(2-methyl-2-propanyl)phenyl]propanoate} Irganox® L109 35074-77-2 \ / $ S ■ U “ ■' II ' " I I. ■ 8 2-[(2-{[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl] oxy} ethyl) sulfanyl]ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate Irganox® L115 41484-35-9 V „ 1 - ...... . I........ V . . / ' 9 4-tertbutyldiphenylamine as a component of Irganox® L57 (68411-46-1) 4496-49-5 li 10 Bipheny 1,4-ylamine 92-67-1 a \ >........ \\ / 7 \ / \\.......: / 11 Nonylphenol 25154- 52-3 mixture of positional isomers CgH-jg' 12 4-methylbenzene-1,3-diamine 95-80-7 XA,, 13 2-(2H-benzotriazol-2-yl)-4,6-called rtpentylphenol 25973- 55-1 rr\XX ch3 HsC CH3 14 4-tert-butylphenol 98-54-4 / --\ / / \ / ?-------. ...... < / \ 15 3,3-bis(4-hydroxyphenyl)-l,3-dih ydro-2-benzofuran-1 -one 77-09-8 Ci - \\__ / / 16 2,4-dinitrotoluene 121-14- 2 . X 17 4- [(4-aminophenyl)methyl 1]aniline (MDA) 101-77- 9 \— / 18 N-phenylaniline ("Diphenylamine" DPA) 122-39- 4 ô 19 N-phenylnaphthalene-1-amine (PAN (alpha)) 90-30-2 20 N-phenylnaphthalene-2-amine (PAN (beta)) 135-88- 6 1 II J 21 2-tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenol 119-47- 1 .S--1'"-.. ...-•'- v '>H.- 22 N-( 1,3-Dimethylbutyl)-N'-phenyl -p-phenylenediamine (6PPD) 793-24- 8 ( x' Vf ZI / / \\ H .. N v / rrr 23 N-Isopropyl-N'-phenyl-p-phenylè nediamine (IPPD) 101-72- 4 ax HH 24 N,N'-Bis(1,4-dimethylpentyl)-Pp henylenediamine (77PD) 3081-1 4-9 ......( / b

[0095] Thus, the examples named A to C are according to the invention and the examples named 1 to 25 are comparative examples (standard antioxidants and anti-ozonants).

[0096] The results of the QSAR modeling are illustrated in Table 5 below: [Tables 5] Ex. QSAR Carcinogenic QSAR Mutagenic QSAR Reprotoxic QSAR Neurotoxic A 0.0 0.0 32.4 0.5 B 0.4 0.1 44.6 0.0 1 64.1 8.0 60.0 0.4 2 86.0 31.6 83.5 6.0 3 72.9 0.2 60.0 2.4 4 84.2 3.1 74.9 0.5 5 83.3 5.5 76.4 2.9 6 85.6 3.5 76.7 5.4 7 74.7 0.3 67.3 0.0 8 69.5 0.3 76.4 0.0 9 78.0 19.4 84.1 30.0 10 93.1 84.7 94.0 83.3 11 91.8 28.5 93.2 37.2 12 99.6 96.7 99.4 93.0 13 96.0 40.1 85.9 8.1 14 95.5 71.4 89.0 73.2 15 86.2 13.9 83.3 3.3 16 99.1 93.6 94.0 43.9 17 98.7 93.5 98.5 70.1 18 95.5 79.7 95.5 95.7 19 92.4 73.3 88.1 70.8 20 90.6 78.2 88.5 59.9 21 85.8 5.0 76.4 9.1 22 77.3 21.1 78.8 8.8 23 87.3 40.4 88.2 11.2 24 90.2 38.2 91.0 17.2 25 63.6 55.6 83.5 11.0

[0097] As shown in Table 5 above, antioxidants comprising an oligomer and / or a polymer comprising at least one diphenylamine repeating unit and optionally at least one phenyl α-naphthylamine repeating unit according to the invention exhibit both very low neurotoxicity, reproductive toxicity, mutagenicity, and low carcinogenicity. In contrast, the compounds composing standard anti-ozonant antioxidants are generally highly toxic, whether in terms of neurotoxicity, reproductive toxicity, mutagenicity, and / or carcinogenicity.

[0098] This QSAR modelling test therefore demonstrates that oligomers and / or polymers comprising at least one diphenylamine repeat motif and possibly at least one phenyl a-naphthylamine repeat motif according to the invention make it possible to prevent and / or reduce the toxicity of a rubber-based composition.

[0099] Toxicity assessment protocol using in vivo tests

[0100] In order to complement the QSAR modeling tests, the Applicant conducted in vivo tests on models called planarians, invertebrate microorganisms living in water with a cephalic sphere and an apparent neuronal system, used in the literature to assess the neurotoxicity, neurodevelopment, and reproductive toxicity of compounds of concern such as pesticides and other toxic organophosphate compounds (Poirier et al. Médecine / Sciences (Paris) 2019; 35 (6-7):544-8 “The planarian, an original animal model for toxicology”; Collins et al. US-2020209223-A1; D. Hagstrom et al. Archives of Toxicology, 2017 91(8), 2837-2847; Zhang et al. TOXICOLOGICAL SCIENCES, 2018, 1-19; Ireland et al. Chemosphere, 2020, 253, 126718). The tests are carried out under conditions close to those reported in the publication mentioned (Zhang et al. TOXICOLOGICAL SCIENCES, 2018, 1-19).

[0101] The operating conditions used are as follows: - Number of test concentrations per chemical: 5 - Concentration ranges: 0.22 mg / L - 22 mg / L in semi-logarithmic increments - Organism studied: whole adult planarians - Test duration: 12 days with an evaluation of the control points at 7 and 12 days - Control points: lethality, adhesion (production of sticky mucus by the skin leading the planarian to be stuck to a wall rather than floating), speed of movement, rest (proportion of rest time compared to time spent moving), phototaxis and "scrunching" (specific mode of movement nominally used by the planarian in case of danger, here excessive heat). - Number of replicas: 3

[0102] The methodology used is described below: - all compounds are supplied in powder form; - an appropriate volume of DMSO 100% (Sigma) was added, as indicated on the tubes, to obtain 200 times the broth at 4.4 mg / ml; - Screening was carried out in three copies of the boxes, following the same procedure for assembling the boxes as described in Zhang et al., Neuro-toxicology and Teratology, 2019. [Tableauxô] Ex. Concentration at which behavioral disturbances potentially linked to cognitive impairment are observed in planarians** Concentration at which significant mortality in planarians is observed according to Zhang et al., Neurotoxicology and Teratology, 2019 C (Table 4) > 22 mg / L > 22 mg / L 19 2.2 - 3.9 mg / L 6.9 mg / L 22 1.5 mg / L 4.8 mg / L **Recorded behavioral disorders: adhesion (production of sticky mucus by the skin leading the planarian to be stuck to a wall rather than floating), speed of movement, rest (proportion of rest time compared to time spent moving), phototaxis and "scrunching" (specific mode of movement nominally used by the planarian in case of danger, here excessive heat).

[0103] This test shows that the antioxidants according to the invention (mixture of compounds A and B) exhibit an absence of toxicity in vivo, particularly in comparison with the comparative antioxidants PAN alpha and 6PPD. Example 2: Antioxidant performance of oligomeric and / or polymer compounds used according to the invention

[0104] Formulations tested:

[0105] For this test, two types of rubber were prepared and evaluated: HNBR rubber, which is a hydrogenated butadiene-acrylonitrile rubber, and AEM rubber (VAMAC®), which is an ethylene acrylic rubber.

[0106] For each rubber, three formulations were prepared by varying only the antioxidant, which is: - either a standard antioxidant of the prior art, namely Bis[4-(2-phenyl-2-propyl)phenyl]amine, CAS 10081-67-1 (corresponding to the commercial product Naugard 445®, a high-performance and high-temperature reference on the rubber additives market), - either a mixture of this standard antioxidant with an antioxidant according to the invention corresponding to Example C of table 4. - either the antioxidant according to the invention (Example C).

[0107] HNBR type rubbers are formulated according to the composition summarized in Table 7 below (the proportions are indicated in pc: part percent of elastomer): [Tables7] Compounds Name / Supplier Comp.l Fl F2 Rubber HNBR ZETPROL® 2000 from Zeon 100 100 100 Carbon Black N772 60 60 60 Plasticizer TOTM Oil (Trioctyl Trimellitate) 10 10 10 Antioxidant (high temperature market performance) Naugard 445® 4 2 0 Antioxidant Example C (invention) 0 2 4 Vulcanization Catalyst Active ZnO 3 3 3 Vulcanization Accelerator Stearic Acid 1 1 1 Crosslinking Agent Sulfur 0.5 0.5 0.5 Primary Vulcanization Accelerator MBT 100 (Mercaptobenzothiazole) 0.5 0.5 0.5 Secondary Vulcanization Accelerator TBzTD (Tetrabenzyl thiuram disulfide) 3 3 3

[0108] AEM type rubbers are formulated according to the composition summarized in Table 8 below (proportions are indicated in pc: part percent of elastomer): [Tables 8] Compounds Name / Supplier Comp.2 F3 F4 Rubber VAMAC ULTRA LS 100 100 100 Carbon Black N660 70 70 70 Alcanplast PO 80 15 15 15 Antioxidant (prior art, high-temperature market performance) Naugard 445® 4 2 0 Antioxidant (invention) Example C (invention) 0 2 4 Vulcanization Accelerator Stearic Acid 1 1 1 Dispersion Agent Armeen 18 D 1 1 1 Hexamethylene Diamine Carbamate (accelerator) DIAK 1 1.5 1.5 1.5 Amine on Silica (accelerator) Vulcofact ACT 55 2 2 2

[0109] The six mixtures (i.e., without the vulcanization system) were formulated in a 300 cm³ HAAKE internal mixer, and then an acceleration system was added to a roller mixer. A rheometric control was performed at 180°C for each mixture. HNBR type rubber sheets measuring 150 x 150 x 2 mm were compression molded after 98 min at 180°C. EAM type rubber sheets measuring 150 x 150 x 2 mm were molded after 98 min at 180°C and then post-vulcanized in an oven at 150°C for 4 h.

[0110] Results

[0111] The mechanical properties of these six formulations were evaluated in the initial state (Table 9) and after aging for 10 days at 130°C (Table 10) and the results are as follows: [Table 9] Initial state Properties Comp.1 Fl F2 Comp.2 F3 F4 Density (g / cm3) (NF ISO 2781) 1.16 1.16 1.16 1.26 1.26 1.26 Shore A hardness (NF ISO 7619-1) 54 56 58 71 70 70 Max stress (MPa) (NF ISO 37) 10.1 11.0 10.5 17.4 16.2 17.0 Elongation at max stress (%) (NF ISO 37) 1130 1070 1050 284 284 297 C100% (MPa) (NF ISO 6502) 1.32 1.35 1.40 5.6 5.6 4.7 C300% (MPa) (NF ISO 6502) 2.38 2.56 2.81 / / / C300 / C100 1.80 1.90 2.00 / / / [Table 10] After aging for 10 days at 130°C Properties Comp.l Fl F2 Comp.2 F3 F4 Density (g / cm3) (NF ISO 2781) 1.17 1.17 1.17 1.278 1.277 1.275 Shore A Hardness (NF ISO 7619-1) 62 63 65 73 72 74 Maximum Stress (MPa) (NF ISO 37) 9.8 9.9 9.7 16.9 15.8 16.6 Elongation at Maximum Stress (%) (NF ISO 37) 759 782 782 277 261 283 C100% (MPa) (NF ISO 6502) 2.13 2.09 2.00 5.4 5.9 5.0 C300% (MPa) (NF ISO 6502) 5.83 5.73 5.51 / / / C300 / C100 2.74 2.74 2.76 / / /

[0112] Thus, this test shows that the levels of mechanical performance and aging for rubber compositions obtained with the anti- additive oxidants according to the invention are of the same level, or even at a higher level, compared to the same compositions made from a comparative antioxidant recognized on the market (high performance and high temperature market reference), and this for two different rubber compositions (i.e., HNBR and AEM).

[0113] Of course, various other modifications can be made to the invention within the scope of the annexed claims.

Claims

1. Demands Use of at least one antioxidant in a rubber composition, said at least antioxidant comprising at least one oligomer and / or polymer comprising at least one diphenylamine repeating unit of general formula (I) [Chem.l]

2.

3. in which each of RI to RIO is chosen independently from a hydrogen atom, an alkyl group which is a saturated hydrocarbon group, linear or branched, comprising from 1 to 24 carbon atoms and an aralkyl group which is an alkyl group as described above in which at least one of the carbon atoms is substituted by a monocyclic or polycyclic aromatic hydrocarbon aryl group comprising 5 to 14 carbon atoms, to reduce and / or prevent the toxicity of said rubber composition. Use according to claim 1, wherein the toxicity includes one or more of the following toxicities: neurotoxicity, reprotoxicity, mutagenicity, acute toxicity, carcinogenicity, toxicity to hormone synthesis, degradation and mode of action, and ecotoxicity. Use according to claim 1 or 2, wherein said oligomer and / or polymer also comprises at least one phenyl α-naphthylamine repeating motif of general formula (II): [Chem. 2] RM RI? in which each from R11 to R22 is chosen independently between a hydrogen atom and an alkyl group which is a saturated hydrocarbon group, linear or branched, comprising from 1 to 24 carbon atoms.

4. Use according to any one of the preceding claims, wherein the at least one diphenylamine of formula (I) is an alkylated diphenylamine in which at least one, preferably two, of RI to RIO is an alkyl or aralkyl group, such as a tert-butyl group or a tert-octyl group or an n-nonyl group.

5. Use according to any one of the preceding claims 1 to 4, wherein the at least one diphenylamine of formula (I) is an alkylated diphenylamine in which at least one, preferably two, of RI to R5 is an alkyl or aralkyl group, such as a tert-butyl group or a tert-octyl group and at least one, preferably two, of R6 to RIO is an alkyl or aralkyl group, such as a tert-butyl group or a tert-octyl group.

6. Use according to any one of the preceding claims, wherein the diphenylamine of formula (I) is selected from the group consisting of N,N-diphenylamine, N,N-di-(p-tert-butylphenyl)amine, N,N-di-(p-tert-octylphenyl)amine, N-(p-tert-butylphenyl)-N-phenylamine, N-(p-tert-octylphenyl)-N-phenylamine, N-(p-tert-butylphenyl)-N-(p-tert-octylphenyl)amine and any mixture thereof.

7. Use according to any one of the preceding claims 3 to 6, wherein said oligomer and / or polymer comprising at least one diphenylamine repeating unit is selected from one or more of the following compounds: a di-t-octyl-diphenylamine dimer, a di-t-octyl-diphenylamine trimer, a trimer comprising two di-t-octyl-diphenylamine repeating units and one N-(4-tert-octylphenyl)-1-naphthylamine repeating unit, and the oligomer of the mixture N,N-diphenylamine, N,N-di-(p-tert-butylphenyl)amine, N,N-di-(p-tert-octylphenyl)amine, N-(p-tert-butylphenyl)-N-phenylamine, N-(p-tert-octylphenyl)-N-phenylamine, N-(p-tert-butylphenyl)-N-phenylamine, N-(p-tert-octylphenyl)-N-phenylamine, N-(p-tert-butylphenyl)-1-naphthylamine Iphény 1) amine.

8. Use according to any one of claims 3 to 7, wherein phenyl α-naphthylamine is N-(4-tert-octylphenyl)-1 α-naphthylamine.

9. Use according to any one of the preceding claims 3 to 9, wherein the polymer and / or oligomer comprises in its structure only diphenylamine repeat motifs and optionally phenyl a-naphthylamine repeat motifs.

10. Use according to any one of the preceding claims 3 to 9, wherein the oligomer and / or polymer comprising at least one diphenylamine repeat unit of formula (I) and optionally at least one phenyl α-naphthylamine repeat unit of formula (II) has a QSAR value for measuring each of the following toxicities: neurotoxicity (neurostotoxic QSAR), reprotoxicity (reprotoxic QSAR), mutagenicity (mutagenic QSAR) and carcinogenicity (carcinogenic QSAR), corresponding to a statistical threshold value (%) subtracted from a delta of at least 30%, said statistical threshold value being determined, for each of said toxicities, by QSAR modeling according to the method described in the experimental part.