MXPA97004595A - Elastomer functionalized by means of carboxylic groups or grafted sters, and use thereof to produce functionalized compositions of elastomer / betun adequate to manufacture superfic - Google Patents

Abstract

The present invention relates to: A functionalized elastomer (EF) consisting of an elastomeric substrate having a weight-average molecular weight of (a) 10,000 to 600,000 daltons and a polydispersity index of less than 5, and which is grafted thereon of 0.1 to 10 percent by weight of sequences, based on the weight of the substrate, (b) where R1 is a hydrocarbon radical (x + z + 1) valent, with 1 to 12 carbon atoms, X is H or a radical R of monovalent hydrocarbon with 1 to 12 carbon atoms, z is 0 or 1, and x is an integer from 1 to 3, where x + z < - 3, and the weight average molecular weight (Mw) of said EF is such that the index (c) is less than 20%. The bitumen / EF compositions for manufacturing surfaces can be produced by incorporating said EF into a component of bet.

Description

ELASTOMER FUNCTIONALIZED BY MEANS OF CARBOXYLIC GROUPS OR GRAFTED ESTERS. AND USE OF THE SAME FOR PRODUCE FUNCTIONALIZED COMPOSITIONS OF ELASTOMER / BITUMEN ADEQUATE TO MANUFACTURE SURFACES The invention relates to an elastomer functionalized by carboxyl or ester groups, which are carried by grafted sequences of controlled length. It also relates to the use of this functionalized elastomer for the production of functionalized compositions of elastomer / bitumen, which can be used as coatings and, in particular, as road stabilizers, as bituminous mixtures or, alternatively, as waterproof coatings. Water. The functionalized compositions of elastomer / bitumen are known and are composed of a mixture of one or a number of bitumens, of a functionalized elastomer carrying functional groups of carboxylic acids or their derivatives, for example, esters or anhydrides of carboxylic acids and, optionally , of a salifying agent, capable of reacting with the functional groups of the functionalized eLastomer and thus resulting in the formation of bridges between the macromolecular chains of the functionalized elastomer (US-A-5,189,083, US-A-5, 214, 082, US -A-5, 278, 207 and EP-A-0,548,412).

The functionalized elastomer may be composed of a styrene block copolymer and a conjugated diene, such as butadiene or isoprene, which additionally contain at least one block that is derived from an acrylic monomer, capable of delivering carboxylic acid functional groups by hydrolysis (patents US-A-5,189,083, US-A-5,214,082 and US-A-5, 278, 207) or, alternatively, it can be composed of a block copolymer of styrene and a conjugated diene, such as butadiene or isoprene, which carries grafted chains containing functional groups of carboxylic acid or carboxylic anhydride (US-A-5, 278, 207 and EP-A-0, 548, 412). The salifying agent may be selected from amines, quaternary ammonium salts, metal oxides and hydroxides, alkali metal or alkaline earth metal carbonates, metal carboxylates, alcohols, amino alcohols and epoxides (EP-A-0, 548, 412) . In particular, the salifying agent can be taken from polyfunctional amines having at least two amino functional groups (US-A-5, 278, 207). The elastomers functionalized by caarboxylic acids or groups derived therefrom, used to produce the functionalized elastomer / bitumen compositions of the aforementioned references, have only a limited extent of carboxylic functional groups or their derivatives, attached along macromolecular chains of the elastomer and capable of inducing the formation of entanglements or bridges of these chains between themselves and / or with the bitumen, directly or after the addition of the salifying agent. For this reason, the physico-mechanical characteristics of the elastomer / bitumen functionalized compositions obtained, in particular the plasticity range (difference between the ring and ball softening temperature and Fraass's brittle state point) and the mechanical characteristics at Low temperatures of use, are not completely satisfactory. According to the invention, an elastomer functionalized by grafted carboxyl or ester functional groups is supplied, this elastomer exhibits a polydispersity index very similar to that of the corresponding non-functionalized elastomer and an improved distribution of the functional groups throughout the the macromolecular chains of the elastomer, which makes it possible, during the use of such functionalized elastomer, in the preparation of functionalized elastomer / bitumen compositions, to obtain functionalized elastomer / bitumen compositions exhibiting an expanded range of plasticity, as well as improved characteristics Mechanics of tension. The functionalized elastomer, according to the invention, is of the type containing a substrate elastomer, which has a weight average molecular mass (Mw) or between 10,000 and 600,000 daltons and a Plg poly-dispersity Index less than 5, onto which are grafted, in an amount representing 0.1 to 10% by weight of the substrate, sequences bearing carboxylic functional groups or ester and is characterized because its weight-average molecular mass Mw is such that the ratio is less than 20% and preferably less (Mw) or 12% and in which the sequences grafted onto the substrate correspond to the formula -S - R ^ - (COOX) x, in which, ((SH) ZR] _ denotes a hydrocarbon radical C_ to C] _2, preferably C] _ to Cg, with valence (x + z + 1), X represents H or a monovalent hydrocarbon radical R, C? _ to C] _2 / preferably C ]_ to CQ, z is equal to zero or is 1 and x is an integer that has a value that varies from 1 to 3 and preferably equals 1 or 2, with x + z < 3. The sequence grafted on the substrate of the elastomer, corresponds advantageously to the formula - S - R3 - (COOX) x, where X and x have the meanings mentioned above and R3 denotes a hydrocarbon radical C] _ a C] _? preferably C? _ a Cg, with valence (x + 1), these sequences have, in particular, the formula - S - R3 - (COOH) x.

In the aforementioned formulas of the sequences grafted onto the substrate of the elastomer, the hydrocarbon radical R] _, with valence (x + z + 1), the radical R 3 with valence (x + 1) and the monovalent hydrocarbon radical R , each may represent a saturated, linear or branched aliphatic radical, C ^ a Ci2 t preferably C] _ a Cg, an unsaturated, linear or branched aliphatic radical, C2 a - 2 'preferably C2 to Cg, a cycloaliphatic radical C4 a 2 r preferably Cg to Cg, or an aromatic radical Cg to C] _2, preferably Cg to Cg. The radical R is preferably a linear or branched alkyl radical, at C] _2, preferably Ci to Cg, such as, for example, methyl, ethyl, propyl, butyl, isooctyl, 2-ethylhexyl or n-octyl. Mention may be made, as examples of the sequences corresponding to the formulas given above, that they may be grafted onto the elastomeric substrate, in order to form a functionalized elastomer, according to the invention, of sequences for which, in the above mentioned formulas, X is a hydrogen atom, in particular - S - CH2 - COOH, - S - CH2 - CH2 - COOH, - S - CH2 - CH2 - CH2 - COOH, - S - CH - COOH - S - CH - COOH CH2 - COOH HS - CH - COOH and the corresponding sequences for which the -COOH group is replaced by an ester group -COOR ', where R' is an alkyl group C] _ a C] _2 Yr in particular, C ^ a Cg, such as, for example , methyl, ethyl, propyl, butyl, 2-ethylhexyl, n-octyl or isooctyl. The elastomer forming the substrate of the functionalized elastomer, according to the invention, may be, for example, polyisoprene, polynorbornene, polybutadiene, butyl rubber, ethylene / propylene random copolymer (EPDM) or random ethylene / propylene terpolymer / diene (EPDM). This elastomer is advantageously selected from random or block copolymers of styrene and conjugated diene, in particular of butadiene, isoprene, chloroprene, carboxylated butadiene, or carboxylated isoprene, and more particularly is composed of one or a number of copolymers selected from copolymers of block, with or without a random hinge of styrene and of butadiene, of styrene and of isoprene, of styrene and of chloroprene, of styrene and of butadiene carboxylated or, alternatively, of styrene and of isoprene carboxylated. The copolymer of styrene and conjugated diene and, in particular, each of the copolymers mentioned above two, advantageously has a styrene content, by weight, ranging from 5 to 50%. This weight-average molecular mass (Mw) Q of the substrate elastomer and, in particular, that of the styrene and conjugated diene polymer, and very particularly that of the aforementioned copolymers, can be, for example, between, 000 and 600,000 daltons and preferably is between 30,000 and 400,000 daltons. The polydispersity index of the substrate elastomer, Pio ie the ratio of the weight-average molecular mass (Mw) of the substrate to its number-average molecular mass (Mn) g, is, as indicated above, less than 5 and preferably it is between 1 and 3. The elastomer of the substrate of the functionalized elastomer according to the invention is preferably composed of a copolymer of styrene and of a conjugated diene, selected from copolymers of di- or tri-blocks, with or without a random hinge, of styrene and butadiene, of styrene and of isoprene, of styrene and of butadiene carboxy-side or, alternatively, of styrene and of carboxylated isoprene, having styrene contents by weight, weight-average molecular masses (MW) Q and values of the polydispersity index Pin within the intervals defined above. The functionalized elastomer, according to the invention, advantageously contains a proportion of grafted sequences representing from 0.1 to 6% and preferably from 0.3 to 3% by weight of the substrate elastomer. The functionalized elastomer, supplied by the invention, is advantageously obtained by the grafting technique, which consists of carrying (i) an elastomer of the substrate, as defined above, having a weight-average molecular mass (Mw) Q between 10,000 and 600,000 daltons, and more particularly between 30,000 and 400,000 daltons and a polydispersity index of less than 5 and preferably between 1 and 2, in contact with (ii) a precursor of the carboxylic or ester-containing sequences, composed of at least a compound of the formula: (XOOC) x - R? _ - S - Y, I (SH) Z in which Y denotes a hydrogen atom or a monovalent residue -S - R] _ - (COOX) x, each one of the symbols X, I (SH) ZR] _, z and x have the meanings given above, until the functionalized elastomer has been formed, the amount of the precursor, which represents 0.5 to 25% and preferably 1 to 15 % of the weight of the substrate elastomer, the operation tion of carrying the elastomer in contact with the precursor being carried out in volume or in a solvent medium and / or diluent, at temperatures between 40 and 250 ° C and in the presence of 0.1 to 1.5% and preferably 0.1 to 1% by weight of the substrate elastomer, of a blocked phenol and of 0 to 2% and preferably from 0 to 1.5% by weight of the substrate elastomer, of a tri (dialkylphenyl) phosphite. The precursor of the grafted sequences is advantageously composed of at least one compound having the formula Y1-S-R3- (COOX) x, where Y] _ denotes H or a monovalent residue -S-R3- (COOX) x, and , in particular, of the formula Y2-S-R3- (COOH) x, where Y2 represents H or a monovalent residue -S-R3- (COOH) x, the symbols R3, X and x each have the meanings given above. The presence of the blocked phenol alone or in the combination of the phenol / tri (dialkylphenyl) phosphite blocked in the grafting reaction mixture prevents the elastomer from the substrate from being interlaced during the grafting operation. When the graft reaction mixture contains both the blocked phenol and the tri (dialkylphenyl) phosphite, the amount by weight of the triphosphite is preferably at least equal to and more especially greater than that of the blocked phenol. The blocked phenol is advantageously chosen from compounds corresponding to the formula: OH R2 (CH2Jn-S-R9 O [CH2] n-S-R4 wherein the symbols R2, R9 and R4, which are identical or different, represent monovalent aliphatic hydrocarbon radicals, C] _ to C ^ and more particularly C_ to C? 2 / muY especially methyl and t-butyl for R2 and hexyl, heptyl, nonyl and very particularly octyl for R9 and R4, and n is a number from 0 to 5. With respect to tri (dialkylphenyl) phosphite, it is more particularly selected from compounds corresponding to the formula: wherein the symbols of R5 and Rg, which are identical or different, represent H or monovalent aliphatic hydrocarbon radicals C] _ to C_g and more particularly C_ to C_2 'very especially H, isopropyl or t-butyl, for R5 and H, t-butyl, hexyl, heptyl, octyl or nonyl for Rg. In order to facilitate the bonding, on the elastomer of the substrate, if it is necessary that the sequences are grafted, generated by the precursor compound of In these sequences, it is possible to add a radical initiator to the graft reaction mixture, which generates free radicals at temperatures between 40 and 250 ° C, chosen for the graft, whose radical initiator is, in particular, a peroxide compound. and, for example, a dihydrocarbyl peroxide, such as lauroyl peroxide, benzoyl peroxide, dicumyl peroxide or, alternatively, tertiary di-butyl peroxide. The amount of the radical initiator can vary very widely and can represent, for example, 0.01 to 6% and more particularly 0.05 to 3% by weight of the substrate elastomer. As indicated before, the grafting can be carried out in volume, ie in the absence of any solvent or diluent or, in contrast, in a solvent and / or diluent medium. The elastomer of the substrate can thus advantageously represent from 10 to 100% and preferably from 15 to 100% of the general weight of the elastomer of the substrate and of the solvent and / or diluent medium. This means of solvent and / or diluent in which the grafting reaction can be carried out, can be composed of any liquid which has no effect on the components participating in the grafting reaction and can be chosen, for example, of hydrocarbons, in particular aromatic hydrocarbons, such as ethylbenzene, which are liquid at the temperatures chosen for grafting.

The duration of the graft reaction can vary from a few minutes, for example from 5 to 10 minutes, to several hours, for example from 4 to 5 hours. When the grafting reaction is carried out in a solvent and / or diluent medium, the functionalized elastomer, resulting from the grafting, is separated from the medium by any technique known for this purpose, for example, by a technique which comprises diluting the reaction mixture resulting from the grafting, followed by the precipitation of the diluted mixture of a precipitating liquid, such as acetone. Advantageously, when the precursor of the grafted sequences is a thiol compound having the formula HS-R? - (COOX) x, | more particularly, the formula (SH) Z HS-R3- (COOX) x, and, in particular, the formula HS-R3- (COOH) x, the grafting reaction is carried out at temperatures between 40 and 150 ° C in a solvent and / or diluent medium or in volume.

When the precursor of the grafted sequences is a disulfide compound, having the formula (HOOC) X-R? _- S-S-R? - (COOX) x, | | more particularly the formula (SH) Z (SH) Z (XOOC) X-R3-S-S-R3 ~ (COOX) x, and in particular the formula (HOOC) X-R3-S-S-R3 ~ (COOH) x. it is preferable to carry out the grafting reaction in volume, at temperatures between 150 and 250 ° C and very particularly in the absence of a radical initiator. Mention may be made, as examples of the precursor compounds of the grafted sequences, of: (i) thiol compounds, such as thiol acetic acid (thioglycolic acid) of the formula HS-CH2-COOH, thiolpropionic acid, Formula HS-CH2-CH2-COOH, thiolbutanoic acid, of the formula HS-CH2-CH2-CH2-COOH, mercaptosuccinic acid, of the formula HOOC-CH2-CH-COOH, I SH, dimercaptosuccinic acid, of the formula HOOC-CH-CH-COOH SH SH or thiosalicylic acid, of the formula: (ii) disulfide compounds, such as 2,2'-dithiodiacetic acid, of the formula HOOC-CH2-SS-CH2-COOH, 3,3'-dithiodipropionic acid of the formula HOOC-CH2-CH2-SS-CH2 -CH2-COOH, 4,4'-dithiobutanoic acid of the formula HOOC- (CH 2) 3-SS- (CH 2) 3 -COOH, and 2, 2'-dithiodisalicylic acid, of the formula (iii) esters derived from said acids exemplified above, by the replacement of the -COOH functional groups by the ester -COOR functional groups. where R 'is a C_ to C] _2 alkyl radical and, more particularly, Ci to Cg, such as, for example, methyl, ethyl, propyl, butyl, 2-ethylhexyl, n-octyl or isooctyl. The functionalized elastomer, according to the invention, can be very particularly used for the production of functionalized compositions of elastomer / bitumen, with a wide range of plasticity, by the incorporation, in a bituminous component, of an amount of the functionalized elastomer that represents 0.5 to 255% and, more especially, from 1 to 15% of the weight of the bituminous component. This bituminous component, which is used to form the working composition of elastomer / bitumen, can be composed of one or a number of bitumens, which have a kinematic viscosity, at 100 ° C, between 0.5 x 10 ~ m2 / s and 3 x 10 ~ 2 m2 / s and preferably between 1 x 10 ~ m2 / s and 2 x 10 ~ 2 m2 / s. These bitumens can be direct distillation or vacuum distillation or also blown bitumens or semi-blown, residues of the de-asfaltization of propane or pentane, in fact still some fractions of petroleum or mixtures of bitumens and vacuum distillates or, alternatively, mixtures of at least two of the products that have been justly listed In addition, a kinematic viscosity included within the aforementioned ranges, the bituminous component that forms pacte of the formulation of the elastomer / bitumen functionalized composition, advantageously has a penetrability, at 25CC, defined according to the norm T 66004 of NF, among 5 and 800 and preferably between 10 and 400. The incorporation of the functionalized elastomer in the bituminous component is carried out by kneading the ingredients, the operation is carried out at temperatures between 100 and 230 ° C and, more particularly, between 120 and 190 ° C, for a sufficient period of time, generally of the order of a few tens of minutes to a few hours and, for example, in the order of 30 minutes to 8 hours, in order to form a homogeneous mixture, this mixture constitutes the functionalized composition of elastomer / bitumen. Said mixture can advantageously be added thereto, the operation being carried out with stirring at temperatures between 100 and 230 ° C and, more particularly, between 120 and 190 ° C, one or a number of additives capable of reacting with the carboxylic functional groups carried by the functionalized elastomer, for the purpose of activating or reinforcing the entanglement of the macromolecular chains of the elastomer with each other and / or with the bituminous component and thus reinforcing the physico-mechanical characteristics of the elastomer / bitumen functionalized composition. According to the invention, it is also possible to react the functionalized elastomer first of all with the reactive additive or the reactive additives and then incorporate the reaction product obtained in the bituminous component. These reactive additives can be, in particular, primary or secondary amines, especially polyamines, alcohols, amino alcohols, epoxides or, alternatively, metal compounds. Reactive amine-type additives are, for example, aromatic diamines, such as 1,4-diaminobenzene, 2,4-diaminotoluene, diaminonaphthalene, bis (4-aminophenyl) -sulfone, bis (4-aminophenyl) -ether or bis (4-aminophenyl) methane, aliphatic or cycloaliphatic diamines, such as those of the formula H2-R7-NH2, where R7 denotes a C2 to C2 alkylene a Cg to C2 cycloalkylene radical / For example, ethylene diamine, diaminopropane, diaminobutane, diaminohexane, diaminooctane, diaminodecane, diaminododecane, diaminocyclohexane, diaminocyclooctane or diaminocyclododecane, polyethylenepolyamines or polypropylenepolyamines, such as diethylenetriamine, triethylenetetraamine, tetraethylenepentamine or dipropylenetriamine or also fatty amines or polyamines, that is to say amines or polyamines containing an alkyl or alkenyl radical C] _2 to c18 'attached to the nitrogen atom of an amine group. Reactive alcohol-type additives are, in particular, polyols such as diols or triols, and especially diols of the formula HO-Rg-OH, where Rg denotes a hydrocarbon radical, especially an alkylene radical C2 to Cj_g, arylene Cg a Cg, and cycloalkylene Cg to c8, and polyether diols of the formula HO _ [CqH2qO] r - H, where q is a number ranging from 2 to 6 and especially equals 2 or 3, and r is a number at least Examples of these are, for example, 2 to 20. Examples of these polyols are ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, hexanediol, octanediol and polyhydroxylated polybutadiene. . Reactive additives of the metal compound type are, in particular, compounds such as hydroxides, oxides, alcoholates, carboxylates such as formations and acetates, methoxides, ethoxides, nitrites, carbonates and bicarbonates of metals of Groups I, II, III or VIII of the Periodic Table of the Elements, especially Na, K, Li, Mg, Ca, Cd, Zn, Ba, Al and Fe. The amount of the reactive additive or the reactive additives, which are incorporated into the functionalized composition of elastomer / bitumen, it can vary from 0.01 to 10% and, more particularly, from 0.05 to 5% of the weight of the bituminous component present in the composition. This amount is advantageously between one and four times the stoichiometric amount corresponding to the complete reaction of the reactive additive or of the additives reactive with the functional groups carried by the functionalized elastomer. During production or after it has been produced, the functionalized composition of elastomer / bitumen can also be added, the operation being carried out with stirring at temperatures between 100 and 230 ° C and, more particularly, between 120 and 190 ° C, 1 to 40% and, more especially, 2 to 30%, by weight of the bitumen, of a flow agent, which may be composed, in particular, of a hydrocarbon oil, which has a distillation range of atmospheric pressure, determined in accordance with ASTM D 86-67, between 100 and 600 ° C and more especially between 150 and 400 ° C. This hydrocarbon oil, which can be especially an oil fraction of an aromatic nature, a fraction of the oil of naphthene-aromatic nature, a fraction of the oil of naphthene-paraffinic nature, a fraction of the oil of paraffinic nature, a coal oil or also an oil of vegetable origin, is sufficiently "heavy", to limit the evaporation at the time of its addition to the bitumen and, at the same time, sufficiently "light" to be removed, both as possible, after the elastomer / bitumen functionalized composition containing it has been extended, in order to regain the mechanical properties, which the elastomer / bitumen functionalized composition, prepared without using the flow agent, will have exhibited after of the hot extension. The amount of the flow agent is selected within the range defined above, in order to be compatible with the desired end use at the work site. In addition to the reactive additives and the flow agent, it is also possible to incorporate in the functionalized composition of the elastomer / bitumen, during the production of said composition or after it has been produced, additives that are conventionally employed in the compositions based on the bituminous component. and in polymers, such as promoters of the adhesion of the functionalized composition of the elastomer / bitumen to the mineral-based ones or also fillers, such as talc, carbon black or worn thin tires. In an embodiment employing a hydrocarbon oil, as defined above, as the flow agent, incorporated in the elastomer / bitumen composition, the functionalized elastomer is incorporated in the bituminous component in the form of a stock solution in the oil of hydrocarbon, which constitutes the flow agent.

The stock solution is prepared by contacting the ingredients of which it is composed, ie the hydrocarbon oil acting as the solvent, and the functionalized elastomer, with stirring, at temperatures between 10 and 170 ° C and, more particularly, between 40 and 120 ° C for a sufficient period of time, for example from about 30 minutes to about 90 minutes, to obtain complete dissolution of the functionalized elastomer. The concentration of the functionalized elastomer in the stock solution can vary very widely, especially as a function of the nature of the hydrocarbon oil used to dissolve the functionalized elastomer. Thus, the mother solution can represent, in particular, from 5 to 40% and, more particularly, between 10 and 30% of the oil and hydrocarbon. In order to prepare the functionalized elastomer / bitumen compositions, according to the invention, using the mother solution technique, this stock solution, containing the functionalized elastomer, is mixed with the bituminous component, the operation being carried out at temperatures between 100 and 230 ° C, more particularly between 120 and 190 ° C, with agitation, until obtaining a homogeneous mass. The duration of the mixture can vary, for example, from 10 minutes to 90 minutes. The quantity of the stock solution that is mixed with the bituminous component is selected to providing the desired amount of the functionalized elastomer with respect to the bituminous component, this amount is within the ranges defined above. The functionalized elastomer / bitumen compositions, obtained by the process according to the invention, can be used as they are or also diluted with varying proportions of a bitumen or mixture of bitumens or of a composition, according to the invention, which it has different characteristics, in order to form the functionalized elastomer / bitumen binders, which have selected contents of the functionalized elastomer. These contents can be equal to (undiluted compositions) the contents of the functionalized elastomer in the initial functionalized compositions of elastomer / bitumen or different (dilute compositions) of the latter contents. Dilution of the functionalized compositions of elastomer / bitumen, according to the invention, with a bitumen or bitumen mixture or with a composition, according to the invention, of different characteristics, can be carried out directly or directly, after the preparation of these compositions, when a virtually immediate use of the resulting functionalized elastomer / bitumen binders is required, or alternatively, after more or less a prolonged storage period of the functionalized elastomer / bitumen compositions, when a Delayed use of the resultant elastomer / bitumen functionalized binders is considered. The bitumen or mixture of bitumens, used for the dilution of a functionalized composition of elastomer / bitumen, according to the present invention, can be chosen from the bitumens defined above as being suitable for the preparation of the functionalized compositions of elastomer / bitumen. The dilution of the functionalized composition of elastomer / bitumen, according to the invention, with a bitumen or bitumen mixture, or with a second composition, according to the invention, with a lower content of the functionalized elastomer, in order to form the functionalized elastomer / bitumen binders, with the selected content of the functionalized elastomer, which is smaller than that of the elastomer / bitumen functionalized composition to be diluted, is generally carried out by contacting, with stirring, and at temperatures between 100 and 230 ° C and, more particularly, between 120 and 190 ° C, suitable proportions of the functionalized composition of elastomer / bitumen to be diluted and of the bitumen or bitumen mixture or of the second functionalized composition of elastomer / bitumen . The functionalized elastomer / bitumen binders consisting of the functionalized elastomer / bitumen compositions, according to the invention, or resulting from the dilution of the compositions with a bitumen or a mixture of bitumens or with another functionalized composition of elastomer / bitumen, according to the invention, as long as the desired content of the functionalized elastomer in the binders can be applied directly or after conversion in the aqueous emulsion, to the production of the roadways. of the type of superficial coating, to the production of bituminous mixtures that are put in place with heating or cooling or also to the production of waterproof coatings. The invention is illustrated by the following examples, given without any limitation involved. In these examples, the amounts and percentages are by weight, except when indicated otherwise. In addition, the rheological and mechanical characteristics of the bitumens or of the functionalized compositions of the elastomer / bitumen referred to in the examples are as follows: • Penetrability, expressed in 1/10 of a millimeter and determined according to the standard T 66004 of NF, • ring and ball softening temperature, expressed in degrees centigrade and determined by the ring and ball test, defined by the norm T 66008 of NF, • rheological characteristics of tension, determined according to the norm T 46002 of NF and comprising the amounts: - elongation at break, eb, in%, - tension at rupture, sb, in daN / cm2, • number of Pfeiffer (abbreviated as PN), calculated from the relation: twenty - . 20 - 500A log] _o800 - logio Pen PN = with A = 1 + 50A RBT - 25 where "pen" and "RBT" denote, respectively, the penetrability and the ring and ball temperature, as defined above, this number provides an indication of the temperature susceptibility of the composition. EXAMPLE 1 Synthesis of a styrene / butadiene diblock elastomer, containing grafted carboxylic functionality, introduced by grafting the thiolacetic acid, which is carried out in solution The synthesis was carried out in a three-liter stainless steel reactor , equipped with a band stirrer and with resources to control the temperature. 281 parts of an elastomer, composed of a styrene / butadiene diblock copolymer in solution in 1125 parts of ethylbenzene, were introduced, at 20 ° C, into the reactor maintained under a nitrogen atmosphere, this The copolymer contains 25% styrene and has a weight-average molecular weight (Mw) n of 144,000. 17.9 parts of the thiolacetic acid (HS-CH2-COOH) were then added to the contents of the reactor, followed by 1.4 parts of a blocked phenol, of the formula: OH (product sold by CIBA under the name of Irganox 1520) and 1.7 parts of the triphosphite of the formula (t-butyl- (?) - 0 * and P (product sold by CIBA, under the name of Irgafos 168). the reactor was then brought to 92 ° C, with stirring (200 revolutions / minute) and under a nitrogen pressure of 2 bar, after which, 6 part of a 10% solution of benzoyl peroxide in toluene was added to it, followed, after one hour, by another three parts of said solution After the second addition of the benzoyl peroxide, the contents of the reactor were maintained at a temperature of 92 ° C for three more hours.

At the end of this period, the reaction mixture was cooled and the grafted product was then recovered by evaporation under vacuum of the cooled reaction mixture. A grafted elastomer was obtained, which comprises a block copolymer of styrene / butadiene block, containing 25% of styrene and carrying grafted sequences of -S-CH2-COOH in an amount, determined by infrared spectroscopy, which represents 0.92% of the block copolymer of two blocks. The weight average molecular weight Mw of the grafted elastomer was 138,000 (ratio of | Mw - (Mw) n I of 4.2%) and its content in (Mw) or gel was less than 1%, which testifies a very slight degradation during the graft.

EXAMPLE 2 Synthesis of an elastomer of two blocks of styrene / butadiene, containing grafted carboxyl functionality, introduced by grafting the thiolpropionic acid, which is carried out in solution The synthesis was carried out as described in Example 1, however, the thiolacetic acid was replaced by 20.6 parts of the thiolpropionic acid (HS-CH2-CH2-COOH). A grafted elastomer was obtained, which comprises a block copolymer of two blocks of styrene / butadiene, which contains 25% styrene and carries grafted sequences of -S-CH2-CH2-COOH in an amount, determined by infrared spectroscopy, which represents 1.1% of the block copolymer of two blocks. The weight average molecular mass Mw of the grafted elastomer was 139,000 (ratio of | Mw - (Mw) Q I of 3.5%) and its content in (Mw) or gel was less than 1%. EXAMPLE 3 Synthesis of a styrene / butadiene two-block elastomer, containing grafted carboxyl functionality, introduced by grafting dithio-dipropionic acid, which is carried out in volume. The synthesis was carried out in a multi-kneading vessel. Rotors, of the Bradender type (Rheo ix 600), maintained at 180 ° C and under a nitrogen atmosphere for the duration of the operations. 50 parts of an elastomer composed of a block copolymer of two blocks, identical to that used in Examples 1 and 2, were introduced into the kneading vessel, the block copolymer being protected against oxidation with 0.25 part of the blocked phenol Irganox 1520 and 0.3 part of the Irgafos 168 triphosphite. The mixing speed corresponds to a rotation rate of the rotors of this vessel of 32 revolutions / minute and was applied to the mass present in the vessel, 1.5 parts of dithio-dipropionic acid (HOOC-CH2-CH2-S-CH2-CH2-COOH) were added to the dough and then the contents of the vessel were kneaded for 30 minutes at 180 ° C. At the end of this period, the grafted polymer was removed from the kneader container and then cooled. A grafted elastomer was obtained, which comprises a block copolymer of styrene / butadiene block, containing 25% of styrene and carrying grafted sequences of -S-CH2-CH2-COOH in an amount, determined by infrared spectroscopy , which represents 0.45% of the block copolymer of two blocks. The weight-average molecular mass Mw of the grafted elastomer was 154,500 (ratio of | MW - (Mw) n I of 7.3%). (Mw) o The grafted elastomer had an excellent solubility in the usual solvents, for example ethylbenzene, the obtained solution was free of gels.

EXAMPLE 4 Synthesis of a two-block elastomer of styrene / butadiene, containing grafted carboxyl functionality, introduced by grafting dithio-dipropionic acid, which is carried out in volume The synthesis was carried out as described in Example 3, however, by adding an additional amount of the dithiodipropionic acid within the kneading vessel, 15 minutes after the first quantity has been introduced, this additional amount is also 1.5 parts. A grafted elastomer was obtained, which comprises a block copolymer of styrene / butadiene block, containing 25% of styrene and carrying grafted sequences of -S-CH2-CH2-COOH in an amount, determined by infrared spectroscopy , which represents 0.89% of the block copolymer of two blocks. The weight average molecular weight Mw of the grafted elastomer was 159,000 (ratio of | MW - (Mw) 0 I of 10.4%) The grafted elastomer (Mw) 0 had excellent solubility in the usual solvents, for example ethylbenzene, and the solution obtained was free of gels.

EXAMPLE 5 An elastomer / bitumen control composition (Test 5.A) and functionalized elastomer / bitumen compositions, according to the invention (Tests 5.B to 5.F), were prepared in order to evaluate and compare their physical-mechanical characteristics. The preparations were carried out under the following conditions: Test 5.A (control) Preparation of a non-functionalized elastomer / bitumen composition. 965 parts of a bitumen, which has a penetrability at 25 ° C, determined in accordance with the conditions of the standard N 66004 of NF, 63 and 35 parts of a block copolymer of two blocks of styrene and of butadiene as the elastomer, were introduced into a reactor maintained at 180 ° C and with stirring, the copolymer has a weight-average molecular mass Mw of 144,000 daltons and contains 25% styrene. After mixing for three hours, with stirring at 180 ° C, a homogeneous mass was obtained which constitutes the non-functionalized elastomer / bitumen composition. - Test 5.B (according to the invention) Preparation of a functionalized elastomer / bitumen composition (grafted functional sequence: -S-CH? -COOH). 940 parts of a bitumen, which has a penetrability at 25 ° C, determined according to the conditions of standard N 66004 of NF, 88 and 60 parts of an elastomer containing grafted carboxylic functionality, composed of the grafted copolymer obtained as described in Example 1, they were introduced into a reactor maintained at 180 ° C and with stirring. After mixing for six hours, with stirring at 180 ° C, a homogeneous mass was obtained, which constitutes the functionalized elastomer / bitumen composition. This composition contained 6.4% of the functionalized elastomer with respect to the bituminous component employed. -Proof 5.C (according to the invention) Preparation of a dilute composition of functionalized elastomer / bitumen (grafted functional sequence: -S-CH? -COOH). A functionalized elastomer / bitumen composition with a high content of functionalized elastomer was prepared, the operation was carried out as described in Test 5.B. The functionalized elastomer / bitumen composition thus obtained was then diluted with the same bitumen as used in Example 5B to a final content of 3.5% of the functionalized elastomer in the diluted composition. The dilution operation was carried out at 180 ° C and with stirring, for a period of four hours.

Test 5.D (according to the invention) Preparation of a dilute composition of functionalized elastomer / bitumen (grafted functional sequence: -S-CH9-COOH), neutralized with the reactive additive of the polyamide type. A dilute composition of functionalized elastomer / bitumen was prepared, carrying out the operation as described in Test 5.C. 1.1 parts of a fatty amine, ie N-sebo-3-amino-l-propyltetrahydropyrimidine, sold by the company CECA under the name Polyram L200®, and added to the diluted composition obtained, kept, with stirring, at 180 ° C, and then the whole mixture was kept, with stirring, at 180 ° C for three hours, in order to make it possible for the amine to neutralize the carboxyl functional groups of the functionalized elastomer present in the composition. -Proof 5.E (according to the invention) Preparation of a functionalized elastomer / bitumen composition (grafted functional sequence: -S-CH? -CH? -COOH). The operation was carried out as described in Test 5.C, the functionalized elastomer, containing grafted sequences of -S-CH2-COOH, however, they were replaced by the same amount by weight of the elastomer as contains grafted sequences of -S-CH2-CH2-COOH, obtained as described in Example 4. - Test 5.F (according to the invention) Preparation of the grafted elastomer / bitumen composition (grafted functional sequence: - S-CH9-CH2-COOH) neutralized with a reactive additive of polyamine type. A functionalized elastomer / bitumen composition was prepared, carrying out the operation as described in Test 5.E. 0.64 part of the Polyram L200® fatty amine were incorporated into the composition, thus obtained, the operation was carried out as indicated in test 5.D, in order to neutralize the carboxylic functional groups of the functionalized elastomer present in the composition . The following characteristics were determined for the elastomer / bitumen control composition of Test 5.A and the functionalized elastomer / bitumen compositions, obtained according to the invention, ie the concentrated composition of functionalized elastomer / bitumen, produced in the Test 5.B and dilute functionalized elastomer / bitumen compositions, produced in Tests 5.C to 5.F: Penetrability at 25 ° C (Pen 25), ring and ball softening temperature (RBT), - number of Pfeiffer (PN), rheological characteristics of tension, that is to say: • stress at rupture (sb) elongation at rupture (eb) The results obtained are compared in the following table TABLE TGA grafted sequence: -S-CH2-COOH TPA grafted sequence: -S-CH2-CH2-COOH. Comparing the results shown in the Table, the following conclusions are reached: the replacement of the conventional elastomer of the elastomer / control bitumen composition (Test 5.A) by the same amount by weight of a functionalized elastomer, in accordance with the invention, with sequences -S-CH2-COOH (Test 5.C) or with sequences -S-CH2-CH2-COOH (Test 5.E), improves, by an interlacing effect, the consistency, (higher values of RBT ), the susceptibility to temperature (increase in the number of Pfeiffer) and the elastomericity (greater elongation of tension and greater tension in the maximum elongation) of the composition of elastomer / bitumen); - the addition of a reactive additive, such as, for example, a polyamine (Tests 5.D and 5.F), to the functionalized elastomer / bitumen compositions, according to the invention, further reinforces, by an ionomeric interlacing effect , the consistency, the temperature susceptibility and the elastomericity of the functionalized elastomer / bitumen compositions; - the functionalized elastomer / bitumen compositions for which the elastomer is functionalized by sequences of -S-CH2-CH2-COOH, have physical characteristics- mechanics that are superior to those of the functionalized elastomer / bitumen compositions for which the elastomer is functionalized with the -S-CH2-COOH sequences, as a result of the comparison of Tests 5.C and 5.E or of the tests 5.D and 5.F, which demonstrates greater consistency (RBT), susceptibilities to temperature (number of Pfeiffer) and 'elastomericities (stresses at maximum elongation) for the functionalized elastomer / bitumen compositions of the first type; The concentrated functionalized elastomer / bitumen compositions, which do not gel and which do not separate, even after prolonged storage at high temperatures, can be obtained, for example concentrates containing 6% of the functionalized elastomer (Test 5.B) , the concentrated compositions make it possible to produce, by dilution, dilute functionalized elastomer / bitumen compositions, for example, containing 3.5% of the functionalized elastomer, which behave very well.

Claims (29)

1. CLAIMS 1. A functionalized elastomer, of the type containing a substrate elastomer, having a weight-average molecular mass (Mw) Q between 10,000 and 600,000 daltons, and a polydispersity index of less than 5, on which it is grafted, in an amount representing 0.1 to 10% by weight of the substrate, sequences bearing carboxylic or ester functional groups, characterized in that its weight-average molecule mass, Mw, is such that the ratio is less than 20% and because the sequences (Mw) or grafted on the substrate correspond to the formula: -S - Ri - (COOX) x | , in which (SH) Z R denotes a hydrocarbon radical O? to C? 2, with valencia (x + z + 1), X represents H or a radical R of monovalent hydrocarbon, C to C? 2, z is equal to zero or is 1 and x is an integer that has a value that varies from 1 to 3, with x + z < 3. The functionalized elastomer, according to claim 1, characterized in that the ratio of | Mw - (Mw) or I is less than 12%. (Mw) 0 3. The functionalized elastomer, according to claims 1 or 2, characterized in that the number x, in the formula of the sequences -S-Rx- (COOX) x is equal to I (SH) Z 1 or 2. 4. The functionalized elastomer, according to claims 1 or 3, characterized in that the sequences grafted onto the substrate of the elastomer correspond to the formula - S-R3- (COOX) x, where R3 denotes a hydrocarbon radical 0? to C? 2, preferably O? a Cg, with valence (x + 1), and, in particular, with the formula - S - R3 - (COOH) x. 5. The functionalized elastomer according to one of claims 1 to 4, characterized in that each of the radicals R ?? R3 and R represent a saturated linear or branched aliphatic radical, 0? to C 2, preferably C x to C g, an unsaturated, linear or branched aliphatic radical, C 2 to C 2, preferably C 2 to Cg, a C 4 to C 2 cycloaliphatic radical / preferably C g to C g, or an aromatic C g a radical c12 'preferably Cg to Cg, the radical R is preferably a linear or branched alkyl radical, Cx to C2, preferably an alkyl radical 0? to Cg. 6. A functionalized elastomer according to one of claims 1 to 5, characterized in that the sequences grafted onto the substrate are selected from: - S - CH2 - COOH, - S - CH2 - CH2 - COOH, - S - CH2 - CH2 - CH2 - COOH, - S - CH - COOH - S - CH - COOH CH2 - COOH HS - CH - COOH and the corresponding sequences for which the -COOH group is replaced by an ester group -COOR ', where R' is an alkyl group O? to C 2 and, in particular, a C x to Cg alkyl group. 7. The functionalized elastomer according to one of claims 1 to 6, characterized in that the substrate elastomer is selected from random or block copolymers of styrene and a conjugated diene, in particular butadiene, isoprene, chloroprene, carboxylated butadiene. , or carboxylated isoprene. 8. The functionalized elastomer according to claim 7, characterized in that the elastomer of the substrate is composed of one or a number of copolymers, selected from block copolymers, with or without a random hinge of styrene and of butadiene, of styrene and of isoprene, of styrene and of chloroprene, of styrene and of carboxylated butadiene and of styrene and of isoprene carboxylated, these copolymers are preferably two-block or three-block, with or without a random hinge. 9. The functionalized elastomer according to claim 7 or 8, characterized in that the copolymer of styrene and conjugated diene, which act as a substrate elastomer, have a styrene content, by weight, ranging from 5 to 50% . 10. The functionalized elastomer according to one of claims 1 to 9, characterized in that the weight-average molecular mass (Mw) of the substrate elastomer is between 30,000 and 400,000 daltons. 11. The functionalized elastomer according to one of claims 1 to 10, characterized in that the polydispersity index of the substrate elastomer is between 1 and 3. 12. The functionalized elastomer, according to one of claims 1 to 11, characterized in that it contains, by weight of the substrate elastomer, from 0.1 to 6% and preferably from 0.3 to 3% of grafted sequences. 13. The functionalized elastomer according to one of claims 1 to 12, characterized in that it is obtained by the grafting technique consisting of (i) contacting the elastomer of the substrate with (ii) a precursor of the sequences containing the carboxylic functionality or ester, composed of at least one compound of the formula: (XOOC) x -Rx-S-Y, I (SH) Z wherein Y denotes a hydrogen atom or a monovalent residue -S-Rx- (COOX) x, I (SH) Z until the functionalized elastomer is has formed, the amount of the precursor, which represents 0.5 to 25% and preferably 1 to 15% of the weight of the elastomer of the substrate, the operation of bringing the elastomer into contact with the precursor being carried out in volume or in a solvent and / or diluent medium, at temperatures between 40 and 250 ° C and in the presence of 0.1 to 1.5% and preferably 0.1 to 1% by weight of the substrate elastomer, of a blocked phenol and of 0 to 2 % and preferably 0 to 1.5% by weight of the substrate elastomer, of a tri (dialkylphenyl) phosphite, the precursor is particularly composed of at least one compound having the formula Y? ~ S-R3- (COOX) x, where Yx denotes H or a monovalent residue -S-R3 ~ (COOX) x, and, in particular, of the formula Y2-S-R3- (COOH) x, where Y2 represents nta H or a monovalent residue -S-R3- (COOH) x. 14. The functionalized elastomer according to claim 13, characterized in that the graft reaction mixture contains both a blocked phenol and a tri (dialkylphenyl) phosphite. 15. The functionalized elastomer according to claim 14, characterized in that the amount, by weight, of the triphosphite is equal to or greater than the amount, by weight, of the blocked phenol. 16. The functionalized elastomer according to one of claims 13 to 15, characterized in that the blocked phenol is selected from the compounds of the formula: OH wherein the symbols R2, R9 and R4, which are identical or different, represent monovalent aliphatic hydrocarbon radicals, 0? a Cxg and more particularly Cx to C? 2, and n is a number from 0 to 5. 17. The functionalized elastomer, according to one of claims 13 to 16, characterized in that the tri (dialkylphenyl) phosphite is selected from compounds of the formula: wherein the symbols of R5 and Rg, which are identical or different, represent H or monovalent aliphatic hydrocarbon radicals 0? to Cx and more particularly 0? to Cl2- 18. The functionalized elastomer, according to one of claims 13 to 17, characterized in that the radical initiator, which generates free radicals at temperatures between 40 and 250 ° C, chosen for grafting, is added to the mixture of graft reaction, this radical initiator is, in particular, a peroxide compound and, for example, a dihydrocarbyl peroxide, such as, the amount of the radical initiator represents, in particular, 0.01 to 6% and more particularly of the 0.05 to 3% by weight of the substrate elastomer. 19. The functionalized elastomer according to one of claims 13 to 18, characterized in that the grafting is carried out in a solvent and / or diluent medium or in volume and at temperatures between 40 and 150 ° C, the precursor compound of the carboxylic or ester sequences have the formula HS-R? - (COOX) x, I more especially, the formula (SH) Z HS-R3- (COOX) x, and, in particular, the formula HS-R3- (COOH) x, this precursor has very particularly the formula: HS-CH2-COOH, 'HS-CH2-CH2 - COOH, HS - CH2 - CH2 - CH2 - COOH, HS - CH - COOH HS - CH - COOH or I I CH2 - COOH HS - CH - COOH s- @c COOH or alternatively a formula resulting from the replacement of the -COOH group, in one of the aforementioned formulas, by an ester group -COOR ', where R' represents an alkyl radical Cx to C? 2 and preferably O? to Cg. 20. The functionalized elastomer according to one of claims 13 to 18, characterized in that the grafting is carried out in volume and at temperatures between 150 and 250 ° C, the precursor compound of the carboxylic or ester sequences, which have the formula: (HOOC) XR? -SSR? - (COOX) x, II more particularly the formula (SH) Z (SH) Z (XOOC) x -R3-SS-R3 ~ (COOX) x, and in particular the formula (HOOC) X-R3 ~ SS-R3- (COOH) x, this grafting is advantageously carried out in the absence of the radical initiator and the precursor compound, very particularly, being such as HOOC-CH2-SS-CH2-COOH , HOOC-CH2-CH2 -SS-CH2-CH2-COOH, HOOC-CH2 -CH2-CH2-SS-CH2-CH2-CH2-COOH, or or a compound that is derived from any of these compounds, by the replacement of the -COOH group with an ester group -COOR ', where R' represents an alkyl radical O? to C? 2 and preferably 0? to Cg. Use of the functionalized elastomer according to one of claims 1 to 20, for the production of functionalized elastomer / bitumen compositions with a wide range of plasticity, by the incorporation, within a bituminous component, of a amount of the functionalized elastomer, which represents 0.5 to 25% and more especially 1 to 15% of the weight of the bituminous component. 22. Use, according to claim 21, characterized in that the bituminous component is composed of one or more bitumens, which have a viscosity cinnamate. at 100 ° C, between 0.5 x 10-4 m2 / s and 3 x 10-2 m2 / s, and preferably between 1 x 10-4 m2 / s and 2 x 10-2 m2 / s. 23. Use, according to claim 22, characterized in that the bituminous component has a penetrability, at 25 ° C, defined according to the norm T 66004 of NF, between 5 and 800 and preferably between 10 and 400. 24. Employment , according to one of claims 21 to 23, characterized in that the incorporation of the functionalized elastomer in the bituminous component is carried out by kneading the ingredients, the operation being carried out at temperatures between 100 and 230 ° C and more particularly between 120 and 190 ° C, for a period of time from 30 minutes to 8 hours, in order to form a homogeneous mixture, which constitutes the functionalized composition of elastomer / bitumen. 25. Use, according to claim 24, characterized in that the homogeneous mixture is added, the operation is carried out, with agitation, at temperatures between 100 and 230 ° C and more particularly between 120 and 190 ° C, one or more additives capable of reacting with the carboxylic or ester functional groups carried by the functionalized elastomer, these additives are in particular primary or secondary amines, especially polyamines, alcohols, in particular polyols, aminoalcohols, epoxides or alternatively metal compounds, in particular compounds of the metals of Groups I, II, III and VIII of the Periodic Table of the Elements. Use, according to claim 25, characterized in that the quantity of the reactive additive or the reactive additives, which are incorporated in the functionalized composition of elastomer / bitumen, represents 0.01 to 10% and more particularly 0.05 to 5% of the weight of the bituminous component, present in the composition. 27. Use, according to one of claims 21 to 26, characterized in that the functionalized composition of elastomer / bitumen is added, during production or after it has been produced, from 1 to 40% and more especially from 2 to 30% , by weight, of the bituminous component, of a flow agent, this operation is carried out with stirring, at temperatures between 100 and 230 ° C and more particularly between 120 and 190 ° C, this flow agent being, in in particular, a hydrocarbon oil, which has a range of distillation at atmospheric pressure, determined in accordance with ASTM D 86-87, between 100 and 600 ° C and preferably between 150 and 400 ° C. Use, according to claim 27, characterized in that the flow agent is composed of hydrocarbon oil in which the functionalized elastomer is incorporated in the bituminous component in the form of a stock solution in the hydrocarbon oil constituting the flow agent, the amount of the functionalized elastomer advantageously represents from 5 to 40% and more particularly from 10 to 30% by weight of the hydrocarbon oil. 29. Employment, according to one of claims 21 to 28, characterized in that the functionalized composition of the elastomer / bitumen is used, as such or after dilution with a bituminous component or also with another functionalized composition of elastomer / bitumen, according to with one of claims 21 to 28, which has different characteristics, such as an elastomer / bitumen functionalized binder, which is suitable, in particular, directly or after the conversion in the aqueous emulsion, for the production of roadways of type of superficial coating, for the production of bituminous mixtures, which are placed on the site with heating or cold, or also for the production of waterproof coatings.