HIGH STRENGTH RUBBER COMPOSITION

Abstract

A rubber composition comprises at least one resin based on: (A1) at least one aromatic compound resulting from the reaction between a reactant of formula ():

##STR00001##

where B represents CHO or CH.sub.2OH, () and a reactant of formula () or

##STR00002##

and (A2) at least one phenolic compound chosen from: (A21) at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted; and/or (A22) at least one aromatic monophenol comprising at least one six-membered aromatic ring bearing a single hydroxyl functional group, the two positions ortho to the hydroxyl functional group being unsubstituted or at least one position ortho to and the position para to the hydroxyl functional group being unsubstituted.

Claims

1.-27. (canceled)

28. A rubber composition comprising at least one resin based on: (A1) at least one aromatic compound resulting from the reaction between a reactant of formula (): ##STR00046## where B represents CHO or CH.sub.2OH, and a reactant of formula () or (): ##STR00047## and mixtures thereof, in which Ar represents an optionally substituted aromatic ring, and each R.sub.1 and R.sub.2 radical represents, independently of one another, a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical; and (A2) at least one phenolic compound chosen from: (A21) at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted; (A22) at least one aromatic monophenol comprising at least one six-membered aromatic ring bearing a single hydroxyl functional group, the two positions ortho to the hydroxyl functional group being unsubstituted or at least one position ortho to and the position para to the hydroxyl functional group being unsubstituted; and mixtures thereof.

29. The rubber composition according to claim 28, wherein the aromatic compound (a) corresponds to general formula (II): ##STR00048## where B represents CHO or CH.sub.2OH, X represents O, NR.sub.3, NO, S, SO, SO.sub.2 or SR.sub.4R.sub.5, R.sub.3 represents a hydrogen or an alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl group, and R.sub.4 and R.sub.5 each represent, independently of one another, a hydrogen or an alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl group.

30. The rubber composition according to claim 28, wherein the aromatic compound (a) is selected from the group consisting of 5-(hydroxymethyl)furfural, 2,5-di(hydroxymethyl)furan and mixtures thereof.

31. The rubber composition according to claim 28, wherein the aromatic ring of the aromatic polyphenol bears three hydroxyl functional groups in the meta position with respect to one another.

32. The rubber composition according to claim 28, wherein the two positions ortho to each hydroxyl functional group on the aromatic ring of the aromatic polyphenol are unsubstituted.

33. The rubber composition according to claim 28, wherein at least one of the aromatic rings of the aromatic polyphenol bears three hydroxyl functional groups in the meta position with respect to one another.

34. The rubber composition according to claim 28, wherein each aromatic ring of the aromatic polyphenol is a benzene ring.

35. The rubber composition according to claim 28, wherein the aromatic polyphenol is selected from the group consisting of resorcinol, phloroglucinol, 2,2,4,4-tetrahydroxydiphenyl sulfide, 2,2,4,4-tetrahydroxybenzophenone and mixtures thereof.

36. The rubber composition according to claim 28, wherein the aromatic polyphenol is a pre-condensed resin based on: at least one polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted, and at least one compound capable of reacting with the polyphenol comprising at least one aldehyde functional group and/or one compound capable of reacting with the polyphenol comprising at least two hydroxymethyl functional groups borne by an aromatic ring.

37. The rubber composition according to claim 28 further comprising a diene elastomer selected from the group consisting of polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers and mixtures thereof.

38. The rubber composition according to claim 28, in the cured state.

39. A rubber composition comprising: (A1) at least one aromatic compound resulting from the reaction between a reactant of formula (): ##STR00049## where B represents CHO or CH.sub.2OH, and a reactant of formula () or (): ##STR00050## and mixtures thereof, in which Ar represents an optionally substituted aromatic ring, and each R.sub.1 and R.sub.2 radical represents, independently of one another, a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical; and (A2) at least one phenolic compound chosen from: (A21) at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted; (A22) at least one aromatic monophenol comprising at least one six-membered aromatic ring bearing a single hydroxyl functional group, the two positions ortho to the hydroxyl functional group being unsubstituted or at least one position ortho to and the position para to the hydroxyl functional group being unsubstituted; and mixtures thereof.

40. The rubber composition according to claim 39, in the raw state.

41. A process for the manufacture of a rubber composition in the raw state comprising the step of: mixing at least one aromatic compound (A1) resulting from the reaction between a reactant of formula (): ##STR00051## where B represents CHO or CH.sub.2OH, and a reactant of formula () or (): ##STR00052## and mixtures thereof, in which Ar represents an optionally substituted aromatic ring, and each R.sub.1 and R.sub.2 radical represents, independently of one another, a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical; and at least one phenolic compound (A2) chosen from: (A21) at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted; (A22) at least one aromatic monophenol comprising at least one six-membered aromatic ring bearing a single hydroxyl functional group, the two positions ortho to the hydroxyl functional group being unsubstituted or at least one position ortho to and the position para to the hydroxyl functional group being unsubstituted; and mixtures thereof.

42. A process for the manufacture of a rubber composition in the cured state comprising the steps of: manufacturing a rubber composition in the raw state by mixing: at least one aromatic compound (A1) resulting from the reaction between a reactant of formula (): ##STR00053## where B represents CHO or CH.sub.2OH, and a reactant of formula () or (): ##STR00054## and mixtures thereof, in which Ar represents an optionally substituted aromatic ring, and each R.sub.1 and R.sub.2 radical represents, independently of one another, a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical; and at least one phenolic compound (A2) chosen from: (A21) at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted; (A22) at least one aromatic monophenol comprising at least one six-membered aromatic ring bearing a single hydroxyl functional group, the two positions ortho to the hydroxyl functional group being unsubstituted or at least one position ortho to and the position para to the hydroxyl functional group being unsubstituted; and mixtures thereof; then shaping the rubber composition in the raw state; and then crosslinking the rubber composition during which a resin based on the phenolic compound and on the aromatic compound is crosslinked.

43. A rubber composition obtained by the process of claim 42.

44. A rubber composite reinforced with at least one reinforcing element embedded in a rubber composition of claim 28.

45. A tire comprising a rubber composition according to claim 28.

46. An aromatic compound resulting from the reaction between a reactant of formula (): ##STR00055## where B represents CHO or CH.sub.2OH, and a reactant of formula () or (): ##STR00056## and mixtures thereof, in which: Ar represents an optionally substituted aromatic ring, R.sub.1 represents a monovalent radical selected from the group consisting of: alkyl, aryl, AL-NH.sub.2 with AL representing a monovalent alkyl radical, ARNH.sub.2 with AR representing a monovalent aryl radical, AL-NR.sub.2H with AL representing a monovalent alkyl radical, and AR-NR.sub.2H with AR representing a monovalent aryl radical, or R.sub.1 represents a C(O)R.sub.6 radical, where R.sub.6 represents a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical, and R.sub.2 represents a monovalent radical selected from the group consisting of alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl and alkenyl radicals.

47. A method for manufacturing a reinforcing resin of a rubber composition comprising the step of: using an aromatic compound resulting from the reaction between a reactant of formula (): ##STR00057## where B represents CHO or CH2OH, and a reactant of formula () or (): ##STR00058## and mixtures thereof, in which Ar represents an optionally substituted aromatic ring, and each R.sub.1 and R.sub.2 represents, independently of one another, a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0135] FIG. 1 represents diagrammatically (without observing a specific scale) a radial section of a tyre in accordance with the invention for a vehicle of the heavy-duty type.

[0136] FIG. 2 is a curve representing the change in the rheometric torque for composition I1 and compositions T0 to T2 over a time scale of 120 minutes.

[0137] FIG. 3 is a curve representing the change in the rheometric torque for composition I1 and compositions T0 to T2 over a time scale of 5 minutes.

DETAILED DESCRIPTION

[0138] Rubber composition is understood to mean that the composition comprises at least one elastomer or one rubber (the two terms being synonyms) and at least one other component. A rubber composition thus comprises a matrix of elastomer or of rubber in which at least the other component is dispersed. A rubber composition is in a plastic state in the raw (non-crosslinked) state and in an elastic state in the cured (crosslinked) state but under no circumstances in a liquid state. A rubber composition must not be confused with an elastomer latex, which is a composition in a liquid state comprising a liquid solvent, generally water, and at least one elastomer or one rubber dispersed in the liquid solvent so as to form an emulsion. Thus, the rubber composition is not an aqueous adhesive composition.

[0139] In the present description, unless expressly indicated otherwise, all the percentages (%) shown are percentages by weight. The acronym phr means parts by weight per hundred parts of elastomer.

[0140] Furthermore, any interval of values denoted by the expression between a and b represents the range of values extending from more than a to less than b (that is to say, limits a and b excluded), whereas any interval of values denoted by the expression from a to b means the range of values extending from the limit a up to the limit b (that is to say including the strict limits a and b).

I.1Aromatic Compound A1 of the Rubber CompositionProduct of Reaction Between the Reactants and and/or According to the Invention

[0141] The first essential constituent of the resin is an aromatic compound resulting from the reaction between a reactant of formula ):

##STR00016## [0142] where B represents CHO or CH.sub.2OH [0143] ()

[0144] and a reactant of formula ) or ):

##STR00017##

[0145] and the mixtures of these compounds,

[0146] in which: [0147] Ar represents an optionally substituted aromatic ring, [0148] each R.sub.1 and R.sub.2 radical represents, independently of one another, a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical.

[0149] Without being able to be exhaustive, the inventors believe that the compounds resulting from the reaction comprise, on the aromatic ring of the compound , the following radicals:

##STR00018##

[0150] These radicals may subsequently be involved in other condensation reactions in order to connect the aromatic ring bearing them to another aromatic ring.

[0151] The aromatic compound comprises at least one aromatic ring bearing at least two functional groups, one of these functional groups being a hydroxymethyl functional group and the other being an aldehyde functional group or a hydroxymethyl functional group. Thus, in accordance with the invention, it is the said aromatic ring which bears hydroxymethyl and aldehyde functional groups. The compound according to the invention thus corresponds to the general formula (I):

HOCH.sub.2ArB(I)

where Ar represents an aromatic ring and B represents CHO or CH.sub.2OH.

[0152] The aromatic ring is advantageously a 5- or 6-membered ring comprising, as members, carbon atoms and optionally one or more heteroatoms, in particular nitrogen, oxygen or sulfur atoms, optionally oxidized in the N-oxide or S-oxide form. In one alternative form, the aromatic ring comprises 0, 1 or 2 heteroatom(s). The remainder of the aromatic ring can be substituted or unsubstituted.

[0153] The aromatic ring can bear 0, 1 or 2 aldehyde functional groups, advantageously 0 or 1 aldehyde functional group.

[0154] The aromatic ring can bear 1, 2 or 3 hydroxymethyl functional groups, advantageously 1 or 2 hydroxymethyl functional groups.

[0155] In addition, the aromatic ring can also bear 0, 1 or 2 other functional group(s), in particular hydroxyl functional group(s).

[0156] In the embodiment in which the aromatic ring is a 6-membered ring, the B and hydroxymethyl functional groups are advantageously in the meta or para position with respect to one another.

[0157] In the embodiment in which the aromatic ring is a 5-membered ring, the ring can comprise one or more heteroatoms, in particular nitrogen, oxygen or sulfur atoms, optionally oxidized in the N-oxide or S-oxide form. Advantageously, the aromatic ring comprises 1 or 2 heteroatom(s), preferably 1 heteroatom.

[0158] In this embodiment, in which the aromatic ring is a 5-membered ring, at least one of the three following conditions is met:

[0159] the aromatic ring comprises 0 or a single aldehyde functional group;

[0160] the aromatic ring comprises one or two hydroxymethyl functional groups;

[0161] apart from the aldehyde and hydroxymethyl functional groups, the remainder of the aromatic ring is unsubstituted.

[0162] Advantageously, these three conditions are met.

[0163] In a first case, the aromatic ring comprises:

[0164] a single aldehyde functional group;

[0165] a single hydroxymethyl functional group;

[0166] apart from the aldehyde and hydroxymethyl functional groups, the remainder of the aromatic ring is unsubstituted.

[0167] In a second case, the aromatic ring comprises:

[0168] 0 aldehyde functional group;

[0169] two hydroxymethyl functional groups;

[0170] apart from the hydroxymethyl functional groups, the remainder of the aromatic ring is unsubstituted.

[0171] Advantageously, the compound is of general formula (II):

##STR00019##

in which B represents CHO or CH.sub.2OH, X represents O, NR.sub.3, NO, S, SO, SO.sub.2 or SR.sub.4R.sub.5, R.sub.3 represents a hydrogen or an alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl group and R.sub.4 and R.sub.5 each represent, independently of one another, a hydrogen or an alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl group.

[0172] Advantageously, the compound is of general formula (II):

##STR00020##

in which X and B are as defined above.

[0173] In a particularly advantageous embodiment, B represents CHO. In another embodiment, B represents CH.sub.2OH.

[0174] In the embodiment where B represents CHO, without being able to be exhaustive, the inventors believe that the compounds resulting from this reaction predominantly comprise the following compounds:

##STR00021##

[0175] According to a preferred embodiment, X represents O.

[0176] In one alternative form, the compound is of formula (IIa):

##STR00022##

B being as defined above,
and more particularly of formula (IIa1) or (IIa2):

##STR00023##

[0177] 5-(Hydroxymethyl)furfural (IIa1) is a particularly suitable aldehyde, given that this organic compound can be readily derived from renewable resources. Specifically, it is derived in particular from the dehydration of certain sugars, such as fructose, glucose, sucrose, cellulose and inulin.

[0178] In this embodiment, without being able to be exhaustive, the inventors believe that the compounds resulting from this reaction predominantly comprise the following compounds:

##STR00024##

[0179] In another embodiment, X represents NR.sub.3 or NO, advantageously NR.sub.3. R.sub.3 is as defined above.

[0180] In one alternative form, the compound is of formula (IIb):

##STR00025##

B being as defined above,
and more particularly of formula (IIb1) or (IIb2):

##STR00026##

in which R.sub.3 represents a hydrogen or an alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl group. Advantageously, R.sub.3 represents a hydrogen or a C.sub.1-C.sub.6 alkyl group.

[0181] In another embodiment, X represents S, SO, SO.sub.2 or SR.sub.4R.sub.5.

[0182] In one alternative form, the compound is of formula (IIc):

B being as defined above,

##STR00027##

with X represents S, SR.sub.4R.sub.5, SO or SO.sub.2 and R.sub.4 and R.sub.5 each represent, independently of one another, a hydrogen or an alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl group, B being as defined above;
and more particularly of formula (IIc1) or (IIc2):

##STR00028##

in which X represents S, SR.sub.4R.sub.5, SO or SO.sub.2 and R.sub.4 and R.sub.5 each represent, independently of one another, a hydrogen or an alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl group.

[0183] The compound can thus be:

##STR00029##

[0184] Advantageously, R.sub.4 and R.sub.5 each represent, independently of one another, a C.sub.1-C.sub.6 alkyl radical.

[0185] The compound is advantageously of formula (IIc1) or (IIc2).

[0186] In another alternative form, the aromatic ring is a 6-membered ring, which can comprise 0, one or more heteroatoms, in particular nitrogen, optionally oxidized in the N-oxide form. In one alternative form, the aromatic ring comprises 0, 1 or 2 heteroatom(s).

[0187] The B and hydroxymethyl functional groups are advantageously in the meta or para position with respect to one another.

[0188] The aromatic ring can bear 0, 1 or 2 aldehyde functional groups, advantageously 0 or 1 aldehyde functional group.

[0189] The aromatic ring can bear 1, 2 or 3 hydroxymethyl functional groups, advantageously 1 or 2 hydroxymethyl functional groups.

[0190] In addition, the aromatic ring can also bear 0, 1 or 2 other functional group(s), in particular hydroxyl functional group(s).

[0191] Advantageously, the compound is of general formula (III):

##STR00030##

in which X represents C or NR.sub.3, n has the value 0, 1 or 2, m has the value 0 or 1 and p has the value 1, 2 or 3. R.sub.1 represents a hydrogen or an alkyl, aryl, arylalkyl, alkylaryl or cycloalkyl group. In accordance with the invention, p+n>1 with p>0.

[0192] Advantageously, R.sub.3 represents a hydrogen or a C.sub.1-C.sub.6 alkyl group.

[0193] In one alternative form, n has the value 1, m has the value 0 and p has the value 1.

[0194] In another alternative form, n has the value 1, m has the value 1 and p has the value 1.

[0195] In another alternative form, n has the value 2, m has the value 1 and p has the value 1.

[0196] In another alternative form, n has the value 1, m has the value 1 and p has the value 2.

[0197] In another alternative form, n has the value 0, m has the value 0 and p has the value 2.

[0198] In another alternative form, n has the value 0, m has the value 1 and p has the value 2.

[0199] In another alternative form, n has the value 1, m has the value 1 and p has the value 2.

[0200] In another alternative form, n has the value 0, m has the value 1 and p has the value 3.

[0201] Preferably, the aromatic ring of the compound of formula (III) is a benzene ring. More preferably, this compound of formula (III) is selected from the group consisting of 2-(hydroxymethyl)benzene-1-carboxaldehyde, 3-(hydroxymethyl)benzene-1-carboxaldehyde, 4-(hydroxymethyl)benzene-1-carboxaldehyde, 3-hydroxymethyl-6-hydroxybenzene-1-carboxaldehyde, 3-hydroxymethyl-4-hydroxybenzene-1-carboxaldehyde, 3-hydroxymethyl-2-hydroxybenzene-1-carboxaldehyde, 3-hydroxymethyl-2-hydroxybenzene-1,5-dicarboxaldehyde, 5-hydroxymethyl-2-hydroxybenzene-1,3-dicarboxaldehyde, 3,5-dihydroxymethyl-4-hydroxybenzene-1-carboxaldehyde, 3,5-dihydroxymethyl-2-hydroxybenzene-1-carboxaldehyde, 1,2-dihydroxymethylbenzene, 1,3-dihydroxmethylbenzene, 1,4-dihydroxymethylbenzene, 1,3-dihydroxymethyl-6-hydroxybenzene, 1,3-dihydroxymethyl-4-hydroxybenzene, 1,3-dihydroxymethyl-2-hydroxybenzene, 1,3,5-trihydroxymethyl-2-hydroxybenzene, 1,3-dihydroxymethyl-6-hydroxybenzene, 1,3,5-trihydroxymethyl-4-hydroxybenzene, 1,3,2-trihydroxymethyl-2-hydroxybenzene and the mixtures of these compounds.

[0202] More preferably still, the aromatic compound used is 1-(hydroxymethyl)benzene-4-carboxaldehyde of formula (IIIa) or 1,4-dihydroxymethylbenzene of formula (IIIb):

##STR00031##

[0203] Preferably, the composition is devoid of formaldehyde and/or devoid of methylene donor selected from the group consisting of hexamethylenetetramine (HMT), hexamethoxymethylmelamine (H3M), hexaethoxymethylmelamine, lauryloxymethylpyridinium chloride, ethoxymethylpyridinium chloride, polymers of hexamethoxymethylmelamine of trioxane of formaldehyde, hexakis(methoxymethyl)melamine, N,N,N-trimethyl-N,N,N-trimethylolmelamine, hexamethylolmelamine, N-methylolmelamine, N,N-dimethylolmelamine, N,N,N-tris(methoxymethyl)melamine, N,N,N-tributyl-N,N,N-trimethylolmelamine. More advantageously, the composition is devoid of formaldehyde and devoid of the methylene donors described in this paragraph.

[0204] More preferably, the composition is devoid of formaldehyde and/or devoid of methylene donor selected from the group consisting of hexamethylenetetramine, hexaethoxymethylmelamine, hexamethoxymethylmelamine, lauryloxymethylpyridinium chloride, ethoxymethylpyridinium chloride, hexamethoxymethylmelamine of trioxane and the N-substituted oxymethylmelamines corresponding to the general formula:

##STR00032##

in which Q represents an alkyl group containing from 1 to 8 carbon atoms; F.sub.1, F.sub.2, F.sub.3, F.sub.4 and F.sub.5 are selected, independently of one another, from the group consisting of a hydrogen atom, of an alkyl group containing from 1 to 8 carbon atoms, of the CH.sub.2OQ group and their condensation products. More advantageously, the composition is devoid of formaldehyde and devoid of the methylene donors described in this paragraph.

[0205] More preferably still, the composition is devoid of formaldehyde and/or devoid of methylene donor. More advantageously, the composition is devoid of formaldehyde and devoid of methylene donors.

[0206] Devoid of formaldehyde or devoid of methylene donor is understood to mean that the total content by weight of formaldehyde or of methylene donor or donors belonging to the groups described above, by total weight of the aromatic compound or compounds A1 in the composition, is less than or equal to 10%, preferably less than or equal to 5%, more preferably less than or equal to 2% and more preferably still less than or equal to 1%.

[0207] Devoid of formaldehyde and devoid of methylene donor is understood to mean that the total content by weight of formaldehyde and of methylene donor or donors belonging to the groups described above, by total weight of the aromatic compound or compounds A1 in the composition, is less than or equal to 10%, preferably less than or equal to 5%, more preferably less than or equal to 2% and more preferably still less than or equal to 1%.

[0208] In one embodiment, the R.sub.1 radical represents a monovalent radical selected from the group consisting of the following radicals: alkyl, aryl, AL-NH.sub.2 with AL representing a monovalent alkyl radical, ARNH.sub.2 with AR representing a monovalent aryl radical, AL-NR.sub.2H with AL representing a monovalent alkyl radical, and ARNR.sub.2H with AR representing a monovalent aryl radical. In this embodiment, the reactant can thus be a primary amine (alkyl and aryl radicals), a primary diamine (AL-NH.sub.2 and ARNH.sub.2 radicals) or a diamine comprising a primary amine functional group and a secondary amine functional group. In this embodiment, the reactant can thus be a secondary amine (alkyl and aryl radicals), a secondary diamine (AL-NR.sub.2H and ARNR.sub.2H radicals) or a diamine comprising a primary amine functional group and a secondary amine functional group.

[0209] Preferably, the R.sub.1 radical represents a monovalent radical selected from the group consisting of the following radicals: AL-NH.sub.2 with AL representing a monovalent alkyl radical, ARNH.sub.2 with AR representing a monovalent aryl radical, AL-NR.sub.2H with AL representing a monovalent alkyl radical, and ARNR.sub.2H with AR representing a monovalent aryl radical. The use of a primary or secondary diamine makes it possible, during the regeneration of the compound from the aromatic compound A1, to generate a diamine in the rubber composition which can be used as molecule which is reactive with regard to other molecules present in the composition, for example with regard to the molecules involved in the vulcanization reaction, in order to accelerate the initiation of the vulcanization.

[0210] More preferably, the monovalent alkyl radical AL is a linear alkyl radical comprising a number of carbon atoms ranging from 1 to 15, preferably from 2 to 12 and more preferably from 2 to 8.

[0211] In another embodiment, the R.sub.1 radical exhibits the following formula:

##STR00033## [0212] in which R.sub.6 represents a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical.

[0213] In a first alternative form, R.sub.6 represents a monovalent radical selected from the group consisting of alkylene, arylene, arylalkylene, alkylarylene, cycloalkylene and alkenylene radicals, preferably from the group consisting of alkylene and arylene radicals. In this alternative form, the reactant or can thus be a primary amide (reactant ) or a secondary amide (reactant ).

[0214] In a second alternative form, the R.sub.1 radical is selected from the group consisting of the radicals of following formulae:

##STR00034## [0215] in which R.sub.6 represents a divalent radical selected from the group consisting of alkylene, arylene, arylalkylene, alkylarylene, cycloalkylene and alkenylene radicals.

[0216] More preferably, the divalent alkylene radical R.sub.6 is a linear alkylene radical comprising a number of carbon atoms ranging from 1 to 15, preferably from 2 to 12 and more preferably from 2 to 8.

[0217] In this alternative form, the reactant or can thus be a primary diamide (reactant ) or a secondary diamide (reactant ) or a diamide comprising a primary amide and a secondary amide.

[0218] In yet another embodiment, the R.sub.1 radical exhibits the following formula:

##STR00035##

[0219] in which R.sub.6 represents NH.sub.2.

[0220] In this other embodiment, the reactant is urea.

[0221] Advantageously, and in any of the embodiments described above for the R.sub.1 radical, the R.sub.2 radical represents a monovalent radical selected from the group consisting of alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl and alkenyl radicals.

[0222] Advantageously, each R.sub.1 and R.sub.2 radical is devoid of a functional group which is reactive with regard to a phenolic compound. Reactive functional group is understood here to mean a functional group which would react under reaction conditions necessary for the regeneration of the compound and under reaction conditions necessary for the crosslinking of the resin. Very preferably, each R.sub.1 and R.sub.2 radical is thus, for example, devoid of an aldehyde and hydroxymethyl functional group.

I.2Phenolic Compound A2 of the Rubber Composition: Aromatic Polyphenol and/or Aromatic MonophenolCompounds A21 and/or A22

[0223] In one embodiment, the second essential constituent of the resin is an aromatic polyphenol A21 comprising one or more aromatic ring(s). The aromatic polyphenol comprises at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted.

[0224] In another embodiment, the second essential constituent of the resin is an aromatic monophenol A22 comprising at least one six-membered aromatic ring bearing a single hydroxyl functional group. On this aromatic monophenol, the two positions ortho to the hydroxyl functional group are unsubstituted, or else at least one position ortho to and the position para to the hydroxyl functional group are unsubstituted.

[0225] In yet another embodiment, the second essential constituent is a mixture of the aromatic polyphenol A21 and of the aromatic monophenol A22 as are described above.

[0226] In accordance with the invention, the compound A21 can be, in one embodiment, a simple molecule of aromatic polyphenol comprising one or more aromatic rings, at least one of these aromatic rings, indeed even each aromatic ring, bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted.

[0227] Analogously, the compound A22 can be, in one embodiment, a simple molecule of aromatic monophenol comprising one or more six-membered aromatic rings, at least one of these six-membered aromatic rings, indeed even each six-membered aromatic ring, bearing a single hydroxyl functional group, the two positions ortho to the hydroxyl functional group are unsubstituted, or else at least one position ortho to and the position para to the hydroxyl functional group are unsubstituted.

[0228] Such simple molecules do not comprise a repeat unit.

[0229] In accordance with the invention, the compound A21 can be, in another embodiment, a pre-condensed resin based:

[0230] on at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted; and

[0231] on at least one compound capable of reacting with the polyphenol comprising at least one aldehyde functional group and/or on at least one compound capable of reacting with the polyphenol comprising at least two hydroxymethyl functional groups borne by an aromatic ring.

[0232] Such a pre-condensed resin based on aromatic polyphenol is in accordance with the invention and comprises, unlike the simple molecule described above, a repeat unit. In the case in point, the repeat unit comprises at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another.

[0233] Analogously and in accordance with the invention, the compound A22 can be, in another embodiment, a pre-condensed resin based:

[0234] on at least one aromatic monophenol comprising at least one six-membered aromatic ring bearing a single hydroxyl functional group: [0235] the two positions ortho to the hydroxyl functional group are unsubstituted or [0236] at least one position ortho to and the position para to the hydroxyl functional group are unsubstituted;

[0237] on at least one compound capable of reacting with the monophenol comprising at least one aldehyde functional group and/or on at least one compound capable of reacting with the monophenol comprising at least two hydroxymethyl functional groups borne by an aromatic ring.

[0238] Such a pre-condensed resin based on aromatic monophenol is in accordance with the invention and comprises, unlike the simple molecule described above, a repeat unit. In the case in point, the repeat unit comprises at least one six-membered aromatic ring bearing a single hydroxyl functional group.

[0239] In another embodiment, the compound A21 is a mixture of an aromatic polyphenol which forms a simple molecule and of a pre-condensed resin based on aromatic polyphenol.

[0240] In another embodiment, the compound A22 is a mixture of an aromatic monophenol which forms a simple molecule and of a pre-condensed resin based on aromatic monophenol.

[0241] In the specific embodiments which follow, the aromatic ring or rings of the aromatic polyphenol and/or of the aromatic monophenol are described. For the sake of clarity, the aromatic polyphenol and/or the aromatic monophenol is described therein in its simple molecule form. This aromatic polyphenol and/or this aromatic monophenol will subsequently be able to be condensed and will in part define the repeat unit. The characteristics of the pre-condensed resin are described in more detail subsequently.

Aromatic Polyphenol A21

[0242] In a preferred embodiment, the aromatic ring of the aromatic polyphenol bears three hydroxyl functional groups in the meta position with respect to one another.

[0243] Preferably, the two positions ortho to each hydroxyl functional group are unsubstituted. This is understood to mean that the two carbon atoms located on either side of (in the position ortho to) the hydroxylated carbon atom (i.e. the carbon atom bearing the hydroxyl functional group) bear a simple hydrogen atom.

[0244] More preferably still, the remainder of the aromatic ring of the aromatic polyphenol is unsubstituted. This is understood to mean that the other carbon atoms of the remainder of the aromatic ring (those other than the carbon atoms bearing the hydroxyl functional groups) bear a simple hydrogen atom.

[0245] In one embodiment, the aromatic polyphenol comprises several aromatic rings, at least two of them each bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups of at least one aromatic ring being unsubstituted.

[0246] In a preferred embodiment, at least one of the aromatic rings of the aromatic polyphenol bears three hydroxyl functional groups in the meta position with respect to one another.

[0247] Preferably, the two positions ortho to each hydroxyl functional group of at least one aromatic ring are unsubstituted.

[0248] More preferably still, the two positions ortho to each hydroxyl functional group of each aromatic ring are unsubstituted.

[0249] More preferably still, the remainder of each of the aromatic rings is unsubstituted. This is understood to mean that the other carbon atoms of the remainder of each aromatic ring (those other than the carbon atoms bearing the hydroxyl functional groups or bearing the group which connects the aromatic rings together) bear a simple hydrogen atom.

[0250] Advantageously, the aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted, is a benzene ring.

[0251] Advantageously, each aromatic ring of the aromatic polyphenol is a benzene ring.

[0252] Mention may in particular be made, as example of aromatic polyphenol comprising just one aromatic ring, of resorcinol and phloroglucinol, as a reminder of expanded formulae (IV) and (V):

##STR00036##

[0253] By way of examples, in the case where the aromatic polyphenol comprises several aromatic rings, at least two of these aromatic rings, which are identical or different, are chosen from those of general formulae:

##STR00037##

in which the Z.sub.1 and Z.sub.2 symbols, which are identical or different, if there are several of them on the same aromatic ring, represent an atom (for example, carbon, sulfur or oxygen) or a connecting group, by definition at least divalent, which connects at least these two aromatic rings to the remainder of the aromatic polyphenol.

[0254] Another example of aromatic polyphenol is 2,2,4,4-tetrahydroxydiphenyl sulfide of following expanded formula (VII):

##STR00038##

[0255] Another example of aromatic polyphenol is 2,2,4,4-tetrahydroxybenzophenone of following expanded formula (VIII):

##STR00039##

[0256] It is noted that each compound VII and VIII is an aromatic polyphenol comprising two aromatic rings (of formulae VI-c), each of which bears at least two (in this case two) hydroxyl functional groups in the meta position with respect to one another.

[0257] It is noted, in the case of an aromatic polyphenol comprising at least one aromatic ring in accordance with the formula VI-b, that the two positions ortho to each hydroxyl functional group of at least one aromatic ring are unsubstituted. In the case of an aromatic polyphenol comprising several aromatic rings in accordance with the formula VI-b, the two positions ortho to each hydroxyl functional group of each aromatic ring are unsubstituted.

[0258] According to one embodiment of the invention, the aromatic polyphenol is selected from the group consisting of resorcinol, phloroglucinol, 2,2,4,4-tetrahydroxydiphenyl sulfide, 2,2,4,4-tetrahydroxybenzophenone, resins pre-condensed from at least one of these phenols and the mixtures of these compounds. In a particularly advantageous embodiment, the aromatic polyphenol is phloroglucinol.

[0259] In one embodiment, the compound A21 comprises a pre-condensed resin based on the aromatic polyphenol as described in any one of these embodiments.

[0260] This pre-condensed resin is advantageously based:

[0261] on at least one aromatic polyphenol as defined above, and preferably selected from the group consisting of resorcinol, phloroglucinol, 2,2,4,4-tetrahydroxydiphenyl sulfide, 2,2,4,4-tetrahydroxybenzophenone and their mixtures; and

[0262] on at least one compound capable of reacting with the polyphenol comprising at least one aldehyde functional group and/or at least one compound capable of reacting with the polyphenol comprising at least two hydroxymethyl functional groups borne by an aromatic ring.

[0263] The compound capable of reacting with the polyphenol comprising at least one aldehyde functional group and/or the compound capable of reacting with the polyphenol comprising at least two hydroxymethyl functional groups borne by an aromatic ring can be an aromatic compound A1 as defined above in section I.1, a compound of formula Ar(CHO).sub.2, where Ar is as defined above for the aromatic compound A1 of section I.1, or any other aldehyde. Advantageously, the said compound capable of reacting with the polyphenol comprising at least one aldehyde functional group and/or the said compound capable of reacting with the polyphenol comprising at least two hydroxymethyl functional groups borne by an aromatic ring is selected from the group consisting of an aromatic compound comprising an aromatic ring bearing at least two functional groups, one of these functional groups being a hydroxymethyl functional group and the other being an aldehyde functional group or a hydroxymethyl functional group, formaldehyde, benzaldehyde, furfuraldehyde, 2,5-furandicarboxaldehyde, 1,4-benzenedicarboxaldehyde, 1,3-benzenedicarboxaldehyde, 1,2-benzenedicarboxaldehyde and the mixtures of these compounds. Very advantageously, when the compound is an aromatic compound comprising an aromatic ring bearing at least two functional groups, one of these functional groups being a hydroxymethyl functional group and the other being an aldehyde functional group or a hydroxymethyl functional group, this compound is selected from the group consisting of 5-(hydroxymethyl)furfural, 2,5-di(hydroxymethyl)furan and the mixtures of these compounds.

[0264] Thus, in the pre-condensed resin based on aromatic polyphenol, the repeat unit corresponds to the characteristics of the aromatic polyphenol defined above except that at least one of the carbon atoms of the aromatic ring, which was unsubstituted, is connected to another unit.

[0265] Whatever the compound other than the aromatic polyphenol at the basis of the pre-condensed resin, this pre-condensed resin is devoid of free formaldehyde. Indeed, even in the case where the pre-condensed resin is based on an aromatic polyphenol as described above and on formaldehyde, since the formaldehyde has already reacted with the aromatic polyphenol, the pre-condensed resin is devoid of free formaldehyde liable to be able to react with a compound A1 in accordance with the invention in a subsequent step.

[0266] The compound A21 can also comprise a mixture of a free molecule of aromatic polyphenol and of a pre-condensed resin based on aromatic polyphenol, such as described above. In particular, the compound A21 can also comprise a mixture of phloroglucinol and of a pre-condensed resin based on phloroglucinol.

Aromatic Monophenol A22

[0267] The monophenol A22 can be in accordance with two alternative forms. In one alternative form, the two positions ortho to the hydroxyl functional group are unsubstituted. In another alternative form, at least one position ortho to and the position para to the hydroxyl functional group are unsubstituted.

[0268] Advantageously, in the alternative form in which at least one position ortho to and the position para to the hydroxyl functional group are unsubstituted, a single ortho position is unsubstituted and the position para to the hydroxyl functional group is unsubstituted.

[0269] Preferably, whatever the alternative form, the two positions ortho to the hydroxyl functional group are unsubstituted. This is understood to mean that the two carbon atoms located on either side of (in the position ortho to) the hydroxylated carbon atom (i.e. the carbon atom bearing the hydroxyl functional group) bear a simple hydrogen atom.

[0270] More preferably still, the remainder of the aromatic ring is unsubstituted. This is understood to mean that the other carbon atoms of the remainder of the aromatic ring (those other than the carbon atoms bearing the hydroxyl functional groups) bear a simple hydrogen atom.

[0271] In one embodiment, the aromatic monophenol comprises several six-membered aromatic rings, at least two of them each bearing a single hydroxyl functional group and, for at least one of the hydroxyl functional groups, the two positions ortho to the hydroxyl functional group are unsubstituted or at least one position ortho to and the position para to the hydroxyl functional group are unsubstituted.

[0272] Preferably, the two positions ortho to each hydroxyl functional group of at least one six-membered aromatic ring are unsubstituted.

[0273] More preferably still, the two positions ortho to each hydroxyl functional group of each six-membered aromatic ring are unsubstituted.

[0274] More preferably still, the remainder of each of the aromatic rings is unsubstituted. This is understood to mean that the other carbon atoms of the remainder of each aromatic ring (those other than the carbon atoms bearing the hydroxyl functional groups or bearing the group which connects the aromatic rings together) bear a simple hydrogen atom.

[0275] Advantageously, the or each aromatic ring of the aromatic monophenol is a benzene ring.

[0276] Preferably, the aromatic monophenol is selected from the group consisting of phenol, ortho-cresol, meta-cresol, para-cresol, ortho-chlorophenol, meta-chlorophenol, para-chlorophenol, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 4-vinylphenol, 4-ethylphenol, 4-isopropylphenol, 4-isobutylphenol, para-coumaric acid and the mixtures of these compounds.

[0277] In one embodiment, the compound A22 comprises a pre-condensed resin based on the aromatic monophenol as described in any one of these embodiments.

[0278] This pre-condensed resin is advantageously based:

[0279] on at least one aromatic monophenol as defined above, and preferably selected from the group consisting of phenol, ortho-cresol, meta-cresol, para-cresol, ortho-chlorophenol, meta-chlorophenol, para-chlorophenol, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 4-vinylphenol, 4-ethylphenol, 4-isopropylphenol, 4-isobutylphenol, para-coumaric acid and the mixtures of these compounds; and

[0280] on at least one compound capable of reacting with the monophenol comprising at least one aldehyde functional group and/or at least one compound capable of reacting with the monophenol comprising at least two hydroxymethyl functional groups borne by an aromatic ring.

[0281] The compound capable of reacting with the monophenol comprising at least one aldehyde functional group and/or the compound capable of reacting with the monophenol comprising at least two hydroxymethyl functional groups borne by an aromatic ring can be an aromatic compound A1 as defined above in section I.1, a compound of formula Ar(CHO).sub.2, where Ar is as defined above for the aromatic compound A1 of section I.1, or any other aldehyde. Advantageously, the said compound capable of reacting with the monophenol comprising at least one aldehyde functional group and/or the compound capable of reacting with the monophenol comprising at least two hydroxymethyl functional groups borne by an aromatic ring is selected from the group consisting of an aromatic compound comprising an aromatic ring bearing at least two functional groups, one of these functional groups being a hydroxymethyl functional group and the other being an aldehyde functional group or a hydroxymethyl functional group, formaldehyde, benzaldehyde, furfuraldehyde, 2,5-furandicarboxaldehyde, 1,4-benzenedicarboxaldehyde, 1,3-benzenedicarboxaldehyde, 1,2-benzenedicarboxaldehyde and the mixtures of these compounds. Very advantageously, when the compound is an aromatic compound comprising an aromatic ring bearing at least two functional groups, one of these functional groups being a hydroxymethyl functional group and the other being an aldehyde functional group or a hydroxymethyl functional group, this compound is selected from the group consisting of 5-(hydroxymethyl)furfural, 2,5-di(hydroxymethyl)furan and the mixtures of these compounds.

[0282] Thus, in the pre-condensed resin based on aromatic monophenol, the repeat unit corresponds to the characteristics of the aromatic monophenol defined above except that at least one of the carbon atoms of the six-membered aromatic ring, which was unsubstituted, is connected to another unit.

[0283] Whatever the compound other than the aromatic monophenol at the basis of the pre-condensed resin, this pre-condensed resin is devoid of free formaldehyde. Indeed, even in the case where the pre-condensed resin is based on an aromatic monophenol as described above and on formaldehyde, since the formaldehyde has already reacted with the aromatic monophenol, the pre-condensed resin is devoid of free formaldehyde liable to be able to react with a compound A1 in accordance with the invention in a subsequent step.

[0284] The compound A22 can also comprise a mixture of a free molecule of aromatic monophenol and of a pre-condensed resin based on aromatic monophenol, such as described above. In particular, the compound A22 can also comprise a mixture of phenol and of a pre-condensed resin based on phenol.

Rubber Composition According to the Invention

[0285] In some embodiments, depending on the use of the composition, use will be made of an amount of aromatic compound A1 ranging from 0.1 to 30 phr. Likewise, an amount of phenolic compound A2 ranging from 0.1 to 30 phr will be used.

[0286] In some embodiments, the [aromatic compound A1]:[phenolic compound A2] molar ratio advantageously varies from 3:1 to 1:1, advantageously from 3:1 to 1.5:1.

[0287] Depending on the use which is made of the composition, the rubber composition exhibits, in the cured state, a secant modulus at 10% elongation, MA10, measured according to Standard ASTM D 412 of 1998 (test specimen C), of greater than or equal to 10 MPa, preferably of greater than or equal to 20 MPa, preferentially of greater than or equal to 30 MPa, more preferably of greater than or equal to 40 MPa and more preferably still of greater than or equal to 60 MPa.

[0288] Preferably, the rubber composition comprises a diene elastomer.

[0289] Elastomer or rubber (the two terms being synonyms) of the diene type is understood to mean, generally, an elastomer resulting, at least in part (i.e., a homopolymer or a copolymer), from diene monomers (monomers bearing two conjugated or unconjugated carbon-carbon double bonds).

[0290] Particularly preferably, the diene elastomer of the rubber composition is selected from the group consisting of polybutadienes (BRs), synthetic polyisoprenes (IRs), natural rubber (NR), butadiene copolymers, isoprene copolymers and the mixtures of these elastomers. Such copolymers are more preferably selected from the group consisting of butadiene/styrene copolymers (SBRs), isoprene/butadiene copolymers (BIRs), isoprene/styrene copolymers (SIRs), isoprene/butadiene/styrene copolymers (SBIRs) and the mixtures of such copolymers.

[0291] The rubber compositions can contain just one diene elastomer or a mixture of several diene elastomers, it being possible for the diene elastomer or elastomers to be used in combination with any type of synthetic elastomer other than a diene elastomer, indeed even with polymers other than elastomers, for example thermoplastic polymers.

[0292] Preferably, the rubber composition comprises a reinforcing filler.

[0293] When a reinforcing filler is used, use may be made of any type of reinforcing filler known for its abilities to reinforce a rubber composition which can be used for the manufacture of tyres, for example an organic filler, such as carbon black, a reinforcing inorganic filler, such as silica, or else a blend of these two types of filler, in particular a blend of carbon black and silica.

[0294] All the carbon blacks conventionally used in tyres (tyre-grade blacks) are suitable as carbon blacks. Mention will more particularly be made, for example, of the reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades).

[0295] In the case of the use of carbon blacks with an isoprene elastomer, the carbon blacks might, for example, be already incorporated in the isoprene elastomer in the form of a masterbatch (see, for example, Applications WO 97/36724 or WO 99/16600).

[0296] Mention may be made, as examples of organic fillers other than carbon blacks, of functionalized polyvinylaromatic organic fillers, such as are described in Applications WO-A-2006/069792 and WO-A-2006/069793.

[0297] Reinforcing inorganic filler should be understood, in the present patent application, by definition, as meaning any inorganic or mineral filler, whatever its colour and its origin (natural or synthetic), also known as white filler, clear filler, indeed even non-black filler, in contrast to carbon black, capable of reinforcing by itself alone, without means other than an intermediate coupling agent, a rubber composition intended for the manufacture of tyres, in other words capable of replacing, in its reinforcing role, a conventional tyre-grade carbon black. Such a filler is generally characterized, in a known way, by the presence of hydroxyl (OH) groups at its surface.

[0298] The physical state in which the reinforcing inorganic filler is provided is not important, whether it is in the form of a powder, of microbeads, of granules, of beads or any other appropriate densified form. Of course, reinforcing inorganic filler is also understood to mean mixtures of different reinforcing inorganic fillers, in particular of highly dispersible siliceous and/or aluminous fillers, such as described below.

[0299] Mineral fillers of the siliceous type, especially silica (SiO.sub.2), or of the aluminous type, especially alumina (Al.sub.2O.sub.3), are suitable in particular as reinforcing inorganic fillers. The silica used can be any reinforcing silica known to a person skilled in the art, in particular any precipitated or fumed silica exhibiting a BET specific surface and a CTAB specific surface both of less than 450 m.sup.2/g, preferably from 30 to 400 m.sup.2/g. Mention will be made, as highly dispersible precipitated silicas (HDSs), for example, of the Ultrasil 7000 and Ultrasil 7005 silicas from Evonik, the Zeosil 1165MP, 1135MP and 1115MP silicas from Rhodia, the Hi-Sil EZ150G silica from PPG, the Zeopol 8715, 8745 and 8755 silicas from Huber or the silicas with a high specific surface as described in Application WO 03/16837.

[0300] Finally, a person skilled in the art will understand that, as filler equivalent to the reinforcing inorganic filler described in the present section, use might be made of a reinforcing filler of another nature, in particular organic nature, provided that this reinforcing filler is covered with an inorganic layer, such as silica, or else comprises functional sites, in particular hydroxyl sites, at its surface which require the use of a coupling agent in order to establish the bond between the filler and the elastomer.

[0301] Preferably, the content of total reinforcing filler (carbon black and/or reinforcing inorganic filler, such as silica) is within a range extending from 5 to 120 phr, more preferably from 5 to 100 phr and more preferably still from 5 to 90 phr.

[0302] Preferably, the content of total reinforcing filler is within a range extending from 10 to 120 phr, more preferably from 10 to 100 phr and more preferably still from 10 to 90 phr.

[0303] More preferably, the content of total reinforcing filler is within a range extending from 20 to 120 phr, more preferably from 20 to 100 phr and more preferably still from 20 to 90 phr.

[0304] More preferably still, the content of total reinforcing filler is within a range extending from 30 to 120 phr, more preferably from 30 to 100 phr and more preferably still from 30 to 90 phr.

[0305] The carbon black can advantageously constitute the sole reinforcing filler or the predominant reinforcing filler. Of course, it is possible to use just one carbon black or a blend of several carbon blacks of different ASTM grades. The carbon black can also be used as a blend with other reinforcing fillers and in particular reinforcing inorganic fillers as described above, in particular silica.

[0306] When an inorganic filler (for example silica) is used in the rubber composition, alone or as a blend with carbon black, its content is within a range from 0 to 70 phr, preferably from 0 to 50 phr, in particular also from 5 to 70 phr, and more preferably still this proportion varies from 5 to 50 phr, particularly from 5 to 40 phr.

[0307] Preferably, the rubber composition comprises various additives.

[0308] The rubber compositions can also comprise all or a portion of the usual additives customarily used in elastomer compositions intended for the manufacture of tyres, such as, for example, plasticizers or extending oils, whether the latter are aromatic or non-aromatic in nature, pigments, protective agents, such as antiozone waxes, chemical antiozonants or antioxidants, antifatigue agents or indeed even adhesion promoters.

[0309] Preferably, the rubber composition comprises a crosslinking system, more preferably a vulcanization system.

[0310] The vulcanization system comprises a sulfur-donating agent, for example sulfur.

[0311] Preferably, the vulcanization system comprises vulcanization activators, such as zinc oxide and stearic acid.

[0312] Preferably, the vulcanization system comprises a vulcanization accelerator and/or a vulcanization retarder.

[0313] The sulfur or sulfur-donating agent is used at a preferred content within a range from 0.5 to 10 phr, more preferably within a range from 0.5 to 8.0 phr. The combined vulcanization accelerators, retarders and activators are used at a preferred content within a range from 0.5 to 15 phr. The vulcanization activator or activators is or are used at a preferred content within a range from 0.5 to 12 phr.

[0314] The crosslinking system proper is preferably based on sulfur and on a primary vulcanization accelerator, in particular on an accelerator of the sulfenamide type. Additional to this vulcanization system are various known secondary vulcanization accelerators or vulcanization activators, such as zinc oxide, stearic acid, guanidine derivatives (in particular diphenylguanidine), and the like.

[0315] Use may be made, as (primary or secondary) accelerator, of any compound capable of acting as accelerator for the vulcanization of diene elastomers in the presence of sulfur, in particular accelerators of the thiazole type, and also their derivatives, and accelerators of thiuram type and of zinc dithiocarbamate type. These accelerators are more preferably selected from the group consisting of 2-mercaptobenzothiazole disulfide (abbreviated to MBTS), N-cyclohexyl-2-benzothiazolesulfenamide (abbreviated to CBS), N,N-dicyclohexyl-2-benzothiazolesulfenamide (abbreviated to DCBS), N-(tert-butyl)-2-benzothiazolesulfenamide (abbreviated to TBBS), N-(tert-butyl)-2-benzothiazolesulfenimide (abbreviated to TBSI), zinc dibenzyldithiocarbamate (abbreviated to ZBEC) and the mixtures of these compounds. Preferably, use is made of a primary accelerator of the sulfenamide type.

[0316] In one embodiment, the rubber composition is in the cured, that is to say vulcanized, state. In other embodiments, the composition is in the raw, that is to say non-vulcanized, state, the crosslinked resin having been added subsequently to the non-vulcanized composition.

[0317] In one embodiment, the resin not yet having crosslinked, the rubber composition comprises: [0318] A1) at least one aromatic compound resulting from the reaction between a reactant of formula ):

##STR00040## [0319] where B represents CHO or CH.sub.2OH [0320] () [0321] and a reactant of formula ) or ):

##STR00041##

[0322] and the mixtures of these compounds,

[0323] in which: [0324] Ar represents an optionally substituted aromatic ring, [0325] each R.sub.1 and R.sub.2 radical represents, independently of one another, a

[0326] monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical;

[0327] and [0328] A2) at least one phenolic compound chosen from: [0329] A21) at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted; [0330] A22) at least one aromatic monophenol comprising at least one six-membered aromatic ring bearing a single hydroxyl functional group, [0331] the two positions ortho to the hydroxyl functional group being unsubstituted or [0332] at least one position ortho to and the position para to the hydroxyl functional group being unsubstituted;

[0333] and their mixtures.

[0334] Preferably, in this embodiment, the composition is in the raw, that is to say non-vulcanized, state.

[0335] Preferably, the rubber composition can be used in the tyre in the form of a layer. Layer is understood to mean any three-dimensional element, having any shape and thickness, in particular as a sheet, strip or other element having any cross-section, for example rectangular or triangular.

[0336] Of course, all the characteristics relating to the phenolic compound and to the compound of the composition comprising the resin also apply to the composition comprising the phenolic compound and the compound which are not crosslinked in the resin state.

Rubber Composite According to the Invention

[0337] The rubber composite is reinforced with at least one reinforcing element embedded in the rubber composition according to the invention.

[0338] This rubber composite can be prepared according to a process comprising at least the following steps: [0339] during a first step, combining at least one reinforcing element with a rubber composition (or elastomer; the two terms are synonyms) according to the invention, in order to form a rubber composite reinforced with the reinforcing element; [0340] then, during a second step, crosslinking by curing, for example by vulcanization, preferably under pressure, the composite thus formed.

[0341] Mention may be made, among reinforcing elements, of textile, metallic or textile-metal hybrid reinforcing elements.

[0342] Textile is understood to mean, in a way well known to a person skilled in the art, any material made of a substance other than a metallic substance, whether natural or synthetic, which is capable of being transformed into thread or fibre by any appropriate transformation process. Mention may be made, for example, without the examples below being limiting, of a polymer spinning process, such as, for example, melt spinning, solution spinning or gel spinning.

[0343] This textile material can consist of a thread or fibre, or also of a fabric produced from threads or fibres, for example a woven fabric with warp threads and weft threads, or else a twill fabric with cross threads.

[0344] This textile material of the invention is preferably selected from the group consisting of monofilaments (or individual threads), multifilament fibres, assemblies of such threads or fibres, and the mixtures of such materials. It is more particularly a monofilament, a multifilament fibre or a folded yarn.

[0345] Thread or fibre is generally understood to mean any elongate element of great length relative to its cross section, whatever the shape, for example circular, oblong, rectangular, square, or even flat, of this cross section, it being possible for this thread to be straight or not straight, for example twisted or wavy. The largest dimension of its cross section is preferably less than 5 mm, more preferably less than 3 mm.

[0346] This thread or fibre may take any known form. For example, it may be an individual monofilament of large diameter (for example and preferably equal to or greater than 50 m), a multifilament fibre (consisting of a plurality of individual filaments of small diameter, typically less than 30 m), a textile folded yarn or cord formed from several textile fibres or monofilaments twisted or cabled together, or else an assembly, group or row of threads or fibres, such as, for example, a band or strip comprising several of these monofilaments, fibres, folded yarns or cords grouped together, for example aligned along a main direction, whether straight or not.

[0347] The textile materials can be made of organic or polymeric substance, as well as made of inorganic substance.

[0348] Mention will be made, as examples of inorganic substances, of glass or carbon.

[0349] The invention is preferably implemented with materials made of polymeric substance, of both the thermoplastic and non-thermoplastic type.

[0350] Mention will be made, as examples of polymeric substances of the non-thermoplastic type, for example, of aramid (aromatic polyamide) and cellulose, both natural and artificial, such as cotton, rayon, flax or hemp.

[0351] Mention will preferably be made, as examples of polymeric substances of the thermoplastic type, of aliphatic polyamides and of polyesters. Mention may in particular be made, among the aliphatic polyamides, of the polyamides PA-4,6, PA-6, PA-6,6, PA-11 or PA-12. Mention may be made, among the polyesters, for example, of PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PBT (polybutylene terephthalate), PBN (polybutylene naphthalate), PPT (polypropylene terephthalate) and PPN (polypropylene naphthalate).

[0352] By definition, metallic is understood to mean one or more threadlike elements composed predominantly (that is to say, for more than 50% of its weight) or entirely (for 100% of its weight) of a metallic material. Preferably, the metallic material is steel, more preferably made of pearlitic (or ferritic-pearlitic) carbon steel advantageously comprising between 0.4% and 1.2% by weight of carbon.

[0353] The metallic reinforcing element can be a monofilament, a cord comprising several metallic monofilaments or a multistrand rope comprising several cords, then referred to as strands.

[0354] In the preferred case where the reinforcing element comprises several metallic monofilaments or several strands, the metallic monofilaments or the strands are assembled by twisting or braiding. It should be remembered that there exist two possible techniques for assembling:

[0355] either by twisting: the metallic monofilaments or the strands undergo both a collective twist and an individual twist about their own axis, which generates an untwisting torque on each of the monofilaments or strands;

[0356] or by braiding: the metallic monofilaments or the strands only undergo a collective twist and do not undergo an individual twist about their own axis.

[0357] Optionally, the reinforcing element comprises several monofilaments and is of the rubberized in situ type, that is to say that the reinforcing element is rubberized from the inside, during its actual manufacture, by a filling rubber. Such metallic threadlike elements are known to a person skilled in the art. The composition of the filling rubber may or may not be identical to the rubber composition in which the reinforcing element is embedded.

[0358] Each reinforcing element, when it is textile, is preferably coated with a layer of an adhesive composition or adhesive. The adhesive used is, for example, of the RFL (resorcinol/formaldehyde/latex) type or, for example, as described in the publications WO2013017421, WO2013017422, WO2013017423 or else WO2015007642. Thus, the rubber composition according to the invention is in direct contact with the adhesive composition. The adhesive composition is interposed between the rubber composition according to the invention and the reinforcing element.

Tyre According to the Invention

[0359] Such tyres are, for example, those intended to equip motor vehicles of passenger type, SUVs (Sport Utility Vehicles), two-wheel vehicles (in particular bicycles and motorcycles), aircraft, as for industrial vehicles chosen from vans, heavy-duty vehiclesthat is to say, underground trains, buses, heavy road transport vehicles (lorries, tractors, trailers) or off-road vehicles, such as heavy agricultural vehicles or earthmoving equipment, or other transportation or handling vehicles.

[0360] By way of example, the appended FIG. 1 represents very diagrammatically (without observing a specific scale) a radial section of a tyre in accordance with the invention for a vehicle of the heavy-duty type.

[0361] This tyre 1 comprises a crown 2 reinforced by a crown reinforcement or belt 6, two sidewalls 3 and two beads 4, each of these beads 4 being reinforced with a bead wire 5. The crown 2 is surmounted by a tread, not represented in this diagrammatic figure. A carcass reinforcement 7 is wound around the two bead wires 5 in each bead 4, the turn-up 8 of this reinforcement 7 being, for example, positioned towards the outside of the tyre 1, which is here represented fitted onto its wheel rim 9. The carcass reinforcement 7 is, in a way known per se, composed of at least one ply reinforced by radial cords, for example of metal, that is to say that these cords are positioned virtually parallel to one another and extend from one bead to the other so as to form an angle of between 80 and 90 with the median circumferential plane (plane perpendicular to the axis of rotation of the tyre which is located halfway between the two beads 4 and passes through the middle of the crown reinforcement 6).

[0362] This tyre 1 of the invention has, for example, the characteristic that at least a crown reinforcement 6 and/or its carcass reinforcement 7 comprises a rubber composition or a composite according to the invention. Of course, the invention relates to the objects described above, namely the rubber composite and the tyre, both in the raw state (before curing or vulcanization) and in the cured state (after curing).

Process for the Preparation of the Aromatic Compound According to the Invention

[0363] The reaction between the reactant of formula and the reactant of formula and/or is carried out in a polar solvent. Preferably, the solvent is chosen from the group consisting of tetrahydrofuran, ether and water and more preferably the solvent is water. Water is particularly advantageous as, on the one hand, it is non-reactive with regard to the reactants , and and makes it possible to dissolve these reactants and, on the other hand, makes it possible to easily extract the compound according to the invention, which is not or very slightly soluble therein. In addition, on carrying out the reaction in water, in which the compound is not or very slightly soluble, it precipitates therein and can thus be hydrolysed to restore the starting reactants , and/or .

[0364] In one embodiment, the reaction is carried out with a molar excess of reactant and/or with respect to the reactant . Molar excess is understood to mean that, once the reaction has been carried out, there remains at least 10% of the initial molar amount of the reactant and/or in the reaction medium.

[0365] In an embodiment in which the compound precipitates from the reaction medium, in order to wash the compound, the compound is washed with water, preferably with water exhibiting a temperature of greater than ambient temperature. Use will be made of a temperature which is sufficiently high to promote the dissolution of the possible excess of the reactant and/or and of the other impurities, for example at a temperature of greater than 50 C.

Process for the Manufacture of the Composition According to the Invention

[0366] The manufacturing process described above and below makes it possible to manufacture the composition according to the invention.

[0367] The rubber composition can be manufactured in appropriate mixers using two successive preparation phases well known to a person skilled in the art: [0368] a first phase of thermomechanical working or kneading (non-productive phase) at high temperature, up to a maximum temperature of between 110 C. and 190 C., preferably between 130 C. and 180 C., [0369] followed by a second phase of mechanical working (productive phase) down to a lower temperature, typically of less than 110 C., for example between 40 C. and 100 C., during which finishing phase the crosslinking system is incorporated.

[0370] In one embodiment, the process comprises the following steps:

[0371] incorporating a reinforcing filler in a diene elastomer during a first step (said non-productive step), everything being kneaded thermomechanically (for example, in one or more goes), until a maximum temperature of between 110 C. and 190 C. is reached;

[0372] cooling the combined mixture to a temperature of less than 100 C.;

[0373] subsequently incorporating, during a second step (said productive step), a crosslinking system, the aromatic compound A1 and the phenolic compound A2;

[0374] kneading everything up to a maximum temperature of less than 110 C.

[0375] By way of example, the non-productive phase is carried out in a single thermomechanical step during which, in a first step, all the base constituents necessary (a diene elastomer, reinforcing filler) are introduced into an appropriate mixer, such as a standard internal mixer, followed, in a second step, for example after kneading for one to two minutes, by the other additives, optional additional agents for covering the filler or optional additional processing aids, with the exception of the crosslinking system. The total duration of the kneading, in this non-productive phase, is preferably between 1 and 15 min.

[0376] After cooling the mixture thus obtained, the crosslinking system, the aromatic compound A1 and the phenolic compound A2 are then incorporated in an external mixer, such as an open mill, maintained at a low temperature (for example between 40 C. and 100 C.). The combined mixture is then mixed (productive phase) for a few minutes, for example between 2 and 15 min.

[0377] The final composition thus obtained in the raw state can subsequently be calendered, for example in the form of a sheet or of a plaque, in particular for a laboratory characterization, or else extruded, for example in order to form a rubber profiled element used in the manufacture of a tyre.

[0378] Then, after an optional step of assembling together several compositions formed as plies or strips in the form of a composite or of a raw tyre blank, a step of crosslinking, for example a step of vulcanizing or curing, the composition, the composite or the blank is carried out, during which the resin based on the aromatic compound and on the phenolic compound is crosslinked. The crosslinking step, in this instance the vulcanization or curing step, is carried out at a temperature of greater than or equal to 120 C., preferably of greater than or equal to 140 C. The composition is obtained in the cured state.

[0379] In another embodiment, the process comprises the following steps:

[0380] incorporating a reinforcing filler, the phenolic compound A2 and the aromatic compound A1 in an elastomer, during a first step, everything being kneaded thermomechanically until a maximum temperature of between 110 C. and 190 C. is reached;

[0381] cooling the combined mixture to a temperature of less than 110 C.;

[0382] subsequently incorporating, during a second step, a crosslinking system;

[0383] kneading everything at a temperature of less than 110 C.

[0384] The invention and its advantages will be easily understood in the light of the exemplary embodiments which follow.

EXEMPLARY EMBODIMENTS OF THE INVENTION AND COMPARATIVE TESTS

[0385] These tests demonstrate that:

[0386] the stiffness of the rubber compositions according to the invention is greatly increased with respect to a rubber composition devoid of reinforcing resin (composition T0),

[0387] the stiffness of the rubber composition is similar with respect to a rubber composition using a conventional reinforcing resin based on a methylene acceptor with HMT or H3M as methylene donor (composition T1),

[0388] the stiffness of the rubber composition according to the invention at high temperatures, in particular for temperatures ranging up to 150 C., is improved with respect to a rubber composition devoid of reinforcing resin (composition T0) or with respect to a rubber composition using a reinforcing resin based on the same phenolic compound A2 and on the corresponding aromatic compound (composition T2),

[0389] the resin of the composition according to the invention is devoid of formaldehyde and does not generate any formaldehyde during its formation.

[0390] For this, several rubber compositions, denoted T0 to T2 and I1 below, were prepared as indicated above and are collated in the appended Table 1 below.

[0391] All the compositions T0 to T2 and I1 have a shared part in their formulations (expressed in phr, parts by weight per hundred parts of elastomer): 100 phr of natural rubber, 75 phr of carbon black N326, 1.5 phr of N-(1,3-dimethylbutyl)-N-phenyl-para-phenylenediamine, 1.5 phr of stearic acid, 5 phr of ZnO, 1 phr of N-(tert-butyl)-2-benzothiazolesulfamide and 2.5 phr of insoluble sulfur 20H.

[0392] The composition T0 does not comprise any reinforcing resin added to this shared part.

[0393] In addition to the shared part, the composition T1 comprises a reinforcing resin based on hexamethylenetetramine (1.6 phr) and on a pre-condensed phenolic resin (4 phr). The composition T1 represents a conventional composition of the state of the art exhibiting a greater stiffness than that of the composition T0.

[0394] In addition to the shared part, the composition T2 comprises 14 phr of aromatic polyphenol A21 and 14 phr of 5-(hydroxymethyl)furfural.

[0395] In addition to the shared part, the composition I1 comprises 14 phr of aromatic polyphenol A21 and 23.8 phr of an aromatic compound A1, in this instance the aromatic compound C1, resulting from the reaction between 5-(hydroxymethyl)furfural and hexane-1,6-diamine.

[0396] The compositions T0 to T2 are not in accordance with the invention, unlike the composition I1, which is in accordance with the invention.

[0397] In the raw state, the rubber composition T2, not in accordance with the invention, comprises: [0398] at least one aromatic aldehyde, 5-(hydroxymethyl)furfural, and [0399] at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted.

[0400] In the cured state, the rubber composition T2, not in accordance with the invention, comprises a phenol-aldehyde resin based: [0401] on at least one aromatic aldehyde, 5-(hydroxymethyl)furfural, and [0402] on at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted.

[0403] In the raw state, the rubber composition I1 according to the invention comprises: [0404] at least one compound resulting from the reaction between a reactant which is an aromatic compound, in this instance the compound C1, comprising at least one aromatic ring bearing at least two functional groups, one of these functional groups being a hydroxymethyl functional group and the other being an aldehyde functional group or a hydroxymethyl functional group, and a reactant of formula and/or :

##STR00042##

and the mixtures of these compounds, in which each R.sub.1 and R.sub.2 radical represents, independently of one another, a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical; and [0405] at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted.

[0406] In the cured state, the rubber composition I1 according to the invention comprises a resin based: [0407] on at least one compound resulting from the reaction between a reactant which is an aromatic compound, in this instance the compound C1, comprising at least one aromatic ring bearing at least two functional groups, one of these functional groups being a hydroxymethyl functional group and the other being an aldehyde functional group or a hydroxymethyl functional group, and a reactant of formula and/or :

##STR00043##

and the mixtures of these compounds, in which each R.sub.1 and R.sub.2 radical represents, independently of one another, a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical; and [0408] on at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted.

[0409] The aromatic polyphenol of the resin of each composition T2 and I1 is selected from the group consisting of resorcinol, phloroglucinol, 2,2,4,4-tetrahydroxydiphenyl sulfide, 2,2,4,4-tetrahydroxybenzophenone, resins pre-condensed from these phenols and the mixtures of these phenolic compounds. Each phenolic compound of each composition T2 and I1 comprises a single aromatic ring, in this instance a benzene ring, bearing three, and only three, hydroxyl functional groups in the meta position with respect to one another. In the case in point, this is phloroglucinol.

[0410] For the aromatic polyphenols of each composition T2 and I1, the remainder of the aromatic ring of the aromatic polyphenol is unsubstituted. In particular, the two positions ortho to each hydroxyl functional group are unsubstituted.

[0411] The aromatic compound C1 of the composition I1 according to the invention results from the reaction between 5-(hydroxymethyl)furfural al and hexane-1,6-diamine 1.

[0412] As explained above, for a compound 1 which is 5-(hydroxymethyl)furfural, the compound resulting from the reaction between the reactants of formula and and/or is selected from the group consisting of the compounds of following formulae:

##STR00044##

[0413] The other reactant reacting with the reactant 1 is a reactant of formula :

H.sub.2NR.sub.6

in which R.sub.6 represents a monovalent radical selected from the group consisting of the following radicals: alkyl, aryl, AL-NH.sub.2 with AL representing a monovalent alkyl radical, ARNH.sub.2 with AR representing a monovalent aryl radical, AL-NR.sub.2H with AL representing a monovalent alkyl radical, and ARNR.sub.2H with AR representing a monovalent aryl radical. In the case in point, R.sub.1 represents an AL-NH.sub.2 radical with AL representing a monovalent alkyl radical, in the case in point a hexyl radical. The reactant exhibits the following formula 1:

##STR00045##

[0414] The reactant of formula 1 is hexane-1,6-diamine.

[0415] As a result of the presence of two NH.sub.2 groups on the reactant of formula 1, there are a multitude of products of the reaction.

[0416] For example, the compound C1 is prepared from 5-(hydroxymethyl)furfural (CAS 67-47-0) and from hexane-1,6-diamine (CAS 124-09-4) in a polar solvent. Thus, for example, 20 g of hexane-1,6-diamine are dissolved in 250 ml of water. Then, 16.1 g of 5-(hydroxymethyl)furfural are subsequently added. Everything is mixed at 50 C. for 4 hours with stirring until the compound C1 precipitates. The reaction mixture is then filtered and is washed 5 times consecutively with 100 ml of water at 20 C. in order to remove the residues of hexane-1,6-diamine and 5-(hydroxymethyl)furfural. The final product is finally recovered and then dried in an oven at 70 C. for 48 hours. 20 g of the compound C1 are obtained in the form of a beige powder.

Preparation Process

[0417] In a first step, the reinforcing filler was incorporated in an elastomer, everything being kneaded thermomechanically until a maximum temperature of between 110 C. and 190 C. was reached. The combined mixture was then cooled to a temperature of less than 110 C. Subsequently, during a second step, the crosslinking system, a pre-condensed resin and a methylene donor (T1) or the aromatic polyphenol and 5-(hydroxymethyl)furfural (T2) or the aromatic polyphenol and the aromatic compound C1 (11) were incorporated. At the end of this second step, the mixture was heated to 150 C. until the maximum rheometric torque was obtained, in order to vulcanize the composition and crosslink the resin. The stiffness at 23 C. of the composition was then characterized during a tensile test.

Characterization of the Delay Phase and of the Stiffness at High TemperatureMaximum Rheometric Torque

[0418] The measurements are carried out at 150 C. with an oscillating disc rheometer, according to Standard DIN 53529Part 3 (June 1983). The change in the rheometric torque as a function of time describes the change in the stiffening of the composition as a result of the vulcanization and of the crosslinking of the resin. The maximum rheometric torque Cmax is determined from the change in the rheometric torque and is given in Table 1. The higher the maximum rheometric torque Cmax, the more the composition exhibits a stiffness which can be maintained at high temperature. Each curve representing the change in the rheometric torque respectively of the composition I1 and also those representing the change in the rheometric torque of the compositions T0 to T2 have been represented in FIG. 2 (over a time scale of 120 minutes) and FIG. 3 (over a time scale limited to 5 minutes).

[0419] The higher the maximum rheometric torque Cmax, the more the composition exhibits a stiffness which can be maintained at high temperature.

Characterization of the Stiffness at 23 C.Tensile Test

[0420] These tests make it possible to determine the elasticity stresses and the properties at break. Unless otherwise indicated, they are carried out in accordance with Standard ASTM D 412 of 1998 (test specimen C). The nominal secant moduli (or apparent stresses, in MPa) at 10% elongation (denoted MA10) are measured in second elongation (i.e., after an accommodation cycle). All these tensile measurements are carried out under standard temperature and relative humidity conditions, according to Standard ASTM D 1349 of 1999, and are given in Table 1.

[0421] First of all, the results of Table 1 show that the use of an aromatic polyphenol and of an aromatic compound comprising at least one aromatic ring bearing at least two functional groups, one of these functional groups being a hydroxymethyl functional group and the other being an aldehyde functional group or a hydroxymethyl functional group, in the control composition T2 makes it possible to obtain a stiffness at 23 C. which is much higher than that of a composition devoid of reinforcing resin (T0) and equivalent to that of a composition comprising a reinforcing resin of the state of the art (T1). Furthermore, unlike T1, the composition T2 does not produce formaldehyde during the curing thereof, in this instance by crosslinking or vulcanization.

[0422] The composition according to the invention I1 exhibits a satisfactory retention of the stiffness at high temperatures which is significantly improved with respect to the control composition T2, showing the advantage of the compound A1 in comparison with the compound .

[0423] The invention is not limited to the embodiments described above.

[0424] In other embodiments, it will be possible to envisage for the resin to be based on one or more aromatic compounds A1 and on one or more phenolic compounds A2 in accordance with the invention and, in addition to these constituents, based on one or more additional aldehydes not in accordance with the invention and/or on one or more additional aromatic polyphenols or monophenols not in accordance with the invention.

TABLE-US-00001 TABLE 1 Cmax Composition Methylene donor Phenol MA10 (MPa) (dN .Math. m) T0 / / 6.7 16 T1 Hexamethylene SRF resin(2) 16.5 43 tetramine(1) Aromatic Cmax Composition aldehyde Aromatic polyphenol MA10 (MPa) (dN .Math. m) T2 5-(Hydroxymethyl) Phloroglucinol(4) 15.1 24 furfural(3) Aromatic Cmax Composition compound Aromatic polyphenol MA10 (MPa) (dN .Math. m) I1 C1 Phloroglucinol(4) 16.1 30 (1) Hexamethylenetetramine (from Sigma-Aldrich; of 99% purity); (2) Pre-condensed resin SRF 1524 (from Schenectady; 75% diluted); (3) 5-(Hydroxymethyl)furfural (from Aldrich; of 99% purity); (4) Phloroglucinol (from Alfa Aesar; of 99% purity).