FR2902794A1 - New fluorinated polymers grafted with a compound containing an organic group having an ethylenically unsaturated carbon-carbon bond and at least two alcohol groups, useful e.g. in pipes, tubes, transport/storage containers of hydrocarbons - Google Patents

Abstract

Fluorinated polymers (I) grafted with a compound (Ia) containing an organic group having an ethylenically unsaturated carbon-carbon bond and at least two alcohol groups, are new.

Description

The present invention relates to

  polymeric compositions with adhesive properties. It also relates to certain particular components of these compositions. It also relates to a method for the preparation of these compositions. The invention also relates to multilayer structures in which one of the layers consists of the polymeric composition with adhesive properties. Polyolefins, especially polymers of ethylene and propylene, are known to be used for the manufacture of pipes, tanks, containers and containers for the transport and storage of liquid hydrocarbons, particularly oils. and fuels. However, the chemical resistance and the impermeability of these polymers with respect to these hydrocarbons are not always sufficient for all the uses for which they are intended. To overcome this drawback, a barrier layer of another polymer is then interposed between the hydrocarbon to be conveyed or stored and the polyolefin. Polymers, both chemically resistant and impermeable, frequently used for this purpose, are fluorinated polymers, in particular polymers and copolymers of vinyl fluoride and vinylidene. These fluoropolymers in turn have another disadvantage: they do not adhere well to polyolefins. Therefore, compositions have been developed to improve the adherent properties of fluoropolymers. Thus, the document EP-A-0650987 describes polymers with adhesive properties whose main hydrocarbon chains, containing fluorine, are grafted with compounds comprising functional groups, reactive or polar, having adhesive properties. These functional groups may be carboxyl groups, carboxylic anhydride residues, epoxy groups, hydroxyl groups, isocyanate groups, ester groups, amide groups, amino groups and hydrolyzable groups containing a silyl or cyano radical. These polymers, however, do not adhere sufficiently well to polyolefins. EP-B-206689 relates to a laminate comprising at least two separate adhesive layers in contact consisting of a hydrocarbon polymer

  2 fluorinated modified with a carboxyl group, acid anhydride, hydroxyl or epoxide and a modified alpha-olefin polymer with a carboxyl group, acid anhydride, hydroxyl or epoxide different from the previous. These two separate adhesive layers may be placed on a substrate layer prepared from a material selected from various polymers including polyvinylidene fluoride, polyethylene and nylon. Thus is mentioned a four-layer laminate comprising a polyvinylidene fluoride layer bonded to a polyethylene layer through two separate adhesive layers. This multilayer structure has the disadvantage of being composed of two layers of adhesive and thus a total of four layers, which poses technical problems during coextrusion at the industrial level, more easily technically feasible if it is limited to three layers, so with a single layer of adhesive. The problem therefore lies in the provision of an adhesive which can satisfactorily bond to a thermoplastic fluorocarbon polymer layer on one side and a non-compatible thermoplastic polymer layer on the other side to form multiple polymeric layer structures containing only a single layer of adhesive. The object of the present invention is to provide a composition which strongly adheres, in the form of a single adhesive layer, a thermoplastic fluorocarbon polymer and an incompatible thermoplastic polymer. The present invention therefore primarily relates to polymeric compositions with adhesive properties comprising: (1) at least one fluorinated polymer (A) grafted with at least one compound (a), which compound (a) contains at least one functional group ( fi) capable of imparting adhesion properties to said fluoropolymer; (2) at least one olefinic polymer (B) grafted with at least one compound (b), which compound (b) contains at least one functional group (f2) capable of imparting adhesion properties to said olefinic polymer and of react with the functional group (fi) contained in the compound (a); (3) at least one polymer (C) selected from polyesters and polyamides. In that a polymer is grafted with a certain compound, is usually meant to mean that one or more molecules of this compound have been chemically fixed at different locations along the chains of this polymer. In a particular embodiment of the present invention [mode (I)],

  3, which is usually given preference, part of the amount of functional group (f2) of the compound (b) grafted onto the polymer (B) has reacted with a part of the amount of functional group (f1) of the compound (a) grafted onto the polymer (A), thus chemically bonding polymer (B) to polymer (A). According to this mode, it is referred to that a part of the functional group amount (fi) of the compound (a) and part of the functional group amount (f2) of the compound (b) remain in the non-state. reacted, and thus capable of imparting adhesion properties to the polymer (A) and the polymer (B) respectively. Finally, still according to this particular embodiment, part of the amount of functional group (f1) of the compound (a) grafted onto the polymer (A) and / or part of the amount of functional group (f2) of the compound (b) grafted onto the polymer (B) may also have reacted with the polymer (C). In another embodiment of the present invention [mode (II)], the entire amount of functional group (f 1) of the compound (a) grafted onto the polymer (A) and the entire amount of functional group ( f2) of the compound (b) grafted onto the polymer (B) are in the unreacted state. The polymeric compositions according to this last embodiment of the present invention advantageously serve as precursor compositions for the preparation of the compositions according to mode (I) as detailed above. The polymeric compositions according to the invention comprise at least one fluorinated polymer (A). By fluoropolymer is meant a polymer of which more than 50% by weight of the monomeric units are derived from at least one fluorinated monomer. The fluoropolymer may be a homopolymer; it can also be a copolymer formed by several fluorinated monomers with each other, or a copolymer formed by one or more fluorinated monomers with one or more non-fluorinated monomers. These copolymers may especially be random copolymers, block copolymers or graft copolymers.

  By fluorinated monomer is meant any monomer which comprises at least one fluorine atom; it usually comprises at least one ethylenic unsaturation. By way of examples of fluorinated monomers, mention may be made of fluorinated vinyl monomers, fluorinated styrenic monomers such as 4-fluorostyrene, fluorinated (meth) acrylic monomers such as trifluoroethyl acrylate and fluorinated conjugated dienes such as 2-fluorobutadiene. . The fluorinated monomer is preferably a fluorinated vinyl monomer. By

  The term "fluorinated vinyl monomer" is intended to denote monoethylenically unsaturated fluorinated monomers which are aliphatic and which have as their only heteroatom (s) one or more fluorine atoms and, optionally, one or more chlorine atoms. Examples of fluorinated vinyl monomers that may be mentioned include hydrogen-free vinyl monomers such as tetrafluoroethylene, hexafluoropropylene and chlorotrifluoroethylene, and partially hydrogenated fluorinated vinyl monomers such as vinyl fluoride, trifluoroethylene, and the like. 3,3,3-trifluoropropene and, with particular mention, vinylidene fluoride. By nonfluorinated monomer is meant any monomer free of fluorine atom; it usually comprises at least one ethylenic unsaturation. Examples of non-fluorinated monomers are: alpha-monoolefins, such as, for example, ethylene and propylene; styrene and non-fluorinated styrenic derivatives; non-fluorinated chlorinated monomers such as, for example, vinyl chloride and vinylidene chloride; non-fluorinated vinyl ethers; non-fluorinated vinyl esters such as, for example, vinyl acetate; (meth) acrylic esters, nitriles and amides such as acrylonitrile and acrylamide.

  By way of examples of fluoropolymers, there may be mentioned homopolymers of vinylidene fluoride, of vinyl fluoride, of trifluoroethylene or of chlorotrifluoroethylene, and the copolymers which these fluorinated monomers form with one another or with at least one other fluorinated monomer such as as defined above (including a fluorinated monomer containing no hydrogen atom, such as tetrafluoroethylene or hexafluoropropylene). By way of examples of such co- and terpolymers, mention may be made of the co-and terpolymers of vinylidene fluoride and the co- and terpolymers of chlorotrifluoroethylene with at least one other fluorinated monomer as defined above (including a monomer fluorine containing no hydrogen atom, such as tetrafluoroethylene or hexafluoropropylene). Mention may also be made of copolymers and terpolymers of at least one of the fluorinated monomers mentioned above with at least one non-fluorinated monomer. The fluoropolymer (A) present in the compositions according to the invention is preferably chosen from vinylidene fluoride polymers.

  For purposes of the present invention, a vinylidene fluoride polymer is a fluoropolymer (ie, a polymer of which more than 50% by weight of the monomeric units are derived from at least one fluorinated monomer), including monomeric units derived from vinylidene fluoride. Examples of vinylidene fluoride polymers that may be mentioned include homopolymers of vinylidene fluoride, and copolymers thereof with other ethylenically unsaturated monomers, whether they are fluorinated (examples of other fluorinated monomers with ethylenic unsaturation are vinyl fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene and hexafluoropropylene) or not (examples of non-fluorinated ethylenically unsaturated monomers are alpha-monoolefins such as ethylene and propylene, styrene and non-fluorinated styrenic derivatives, non-fluorinated chlorinated monomers such as vinyl chloride and vinylidene chloride, non-fluorinated vinyl ethers, non-fluorinated vinyl esters such as vinyl acetate, esters, nitriles and amides (meth) non-fluorinated acrylics such as acrylamide and acrylonitrile).

  The vinylidene fluoride polymers preferably contain more than 50% by weight of monomeric units derived from vinylidene fluoride. Particularly preferred vinylidene fluoride polymers are homopolymers of vinylidene fluoride and random copolymers of vinylidene fluoride containing 10 to 20% by weight of a fluorinated comonomer selected from hexafluoropropylene and chlorotrifluoroethylene. According to the invention, the fluoropolymer (A) is functionalized by grafting with at least one compound (a) - defined and described in detail below - which contains at least one functional group (fi) capable of imparting adhesion properties. fluorinated polymer audit.

  The functional group (fi) can be any group having a reactivity or a polarity such that it allows the fluoropolymer to develop adhesion forces, even with respect to materials that it is not normally not possible to adhere to this polymer. The group (fi) is generally chosen from groups bearing at least one reactive function not involved in radical mechanisms. It is most often chosen from: (fl.l) groups derived from carboxylic acids, also simply referred to hereinafter as acidic groups; the carboxylic acids from which these groups originate may be mono- or dicarboxylic acids;

  6 (fl.2) groups derived from carboxylic anhydrides, resulting from the condensation of two carboxylic acid groups in the same molecule, also simply referred to hereinafter as anhydride groups; the carboxylic anhydrides which carry these groups can themselves derive from mono- or dicarboxylic acids; (III.3) groups derived from carboxylic esters, also hereinafter more simply referred to as ester groups; (fl.4) groups derived from carboxylic amides, also more simply referred to hereinafter as amide groups; (fl.5) epoxy groups derived from compounds containing a cyclic ether function; (fl.6) hydroxyl groups derived from alcohols, also hereinafter more simply referred to as alcohol groups; the alcohols from which these groups originate may be monoalcohols or polyols; (fl.7) carbonyl groups; (fl.8) hydrolyzable groups containing a silyl group. Of all these groups, epoxy groups (f1.5), alcohol groups (f1.6) and carbonyl groups (f1.7) are preferred.

  Epoxy groups and alcohol groups derived from diols are more particularly preferred. The alcohol groups derived from diols give the best results. As mentioned, the functionalization of the fluorinated polymer (A) is carried out by grafting, on this polymer, at least one compound (a) containing at least one functional group (fi). According to the invention, the functional group (s) (f 1) carried by the compound (s) can belong to the same family or to different families. Thus, it is in no way excluded to use both a compound (a) containing an epoxy group and another compound (a) containing one or more alcohol groups; likewise, it is in no way excluded to use a compound (a) containing both an ester group and another group, epoxy or alcohol, for example. In order to be grafted onto the fluoropolymer (A), the compound (a) must also contain at least one group (g) making it possible to graft said compound (a) onto this polymer. This group (g) is generally chosen from: saturated or unsaturated hydrocarbon groups capable of participating in radical mechanisms, such as radical additions or combinations; amino groups or phenols capable of participating in nucleophilic reactions; groups capable of readily forming free radicals such as peroxy and azo groups. Preferably, the group (g) is chosen from organic groups having at least one ethylenically unsaturated carbon-carbon bond, from amino groups and from peroxy groups. The organic groups having at least one terminal (a, (3) ethylenically unsaturated carbon-carbon bond, such as vinyl, allyl, acryloyloxyalkyl and methacryloyloxyalkyl, for example, are particularly preferred as group (g). best results Examples of compounds (a) containing at least one organic group having at least one terminal carbon-carbon bond (a, (3) ethylenically unsaturated as groups (g) and at least one acid or anhydride group as group (F1) are unsaturated mono- or dicarboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, bicyclo [2.2.1] hept-2-ene-5,6-dicarboxylic acid, maleic anhydride, itaconic anhydride, crotonic anhydride and citraconic anhydride. p referred, in particular for reasons of accessibility. Examples of compounds (a) containing at least one organic group having at least one terminal carbon-carbon bond (a, (3) ethylenically unsaturated as group (g) and at least one ester group as a group ( ) are vinyl acetate, vinyl propionate, monomethyl maleate, dimethyl maleate, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-propyl acrylate, -butyl, isobutyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, diethyl fumarate, dimethyl itaconate and diethyl citraconate.

  Examples of compounds (a) containing at least one organic group having at least one ethylenically unsaturated terminal carbon-carbon bond (u43) as a group (g) and at least one amide group as a group (fi) are acrylamide and methacrylamide.

  An example of a compound (a) containing at least one organic group having at least one terminal carbon-carbon bond (a43) which is ethylenically unsaturated as a group (g) and at least one epoxy group as a group (f 1) is glycidyl allyl ether. Examples of compounds (a) containing at least one organic group having at least one terminal carbon-carbon bond (a, (3) ethylenically unsaturated as a group (g) and at least one alcohol group as a group ( ) are allyl alcohol and 3-allyloxy-1,2-propanediol Examples of compounds (a) containing at least one organic group having at least one terminal carbon-carbon bond (a, (3) ethylenically unsaturated at As moiety (g) and at least one carbonyl group as moiety (f1) are organic heterocyclic compounds containing a vinyl or allyl group attached to the heteroatom and whose heterocycle bears the carbonyl bond, such as N- vinylpyrrolidone and N-vinylcaprolactam Examples of compounds (a) containing at least one organic group having at least one terminal carbon-carbon bond (a, (3) ethylenically unsaturated as group (g) and at least a hydrolyzable group containing a silyl group as a (fi) group are vinyl trimethoxysilane, vinyl triethoxysilane, vinyl triacetoxysilane, vinyl tris (β-methoxyethoxy) silane and γ-methacryloxypropyltrimethoxysilane. Examples of compounds (a) containing at least one organic group having at least one terminal carbon-carbon bond (a, (3) ethylenically unsaturated as group (g), and at least two functional groups (fi) of nature different are: acrylate and glycidyl methacrylate (an ester group and an epoxy group as (fi) groups), hydroxyethyl acrylate and methacrylate and hydroxypropyl acrylate and methacrylate (a ester group and an alcohol group as groups (f1)), N-methylolmethacrylamide (an alcohol group and an amide group as (fl) groups).

9

  Among all compounds (a), compounds containing at least one functional group (f 1) chosen from epoxy groups, alcohol groups and carbonyl groups, more particularly from alcohol groups derived from diols, are preferred. Allyl glycidyl ether, 3-allyloxy-1,2-propanediol, N-vinylpyrrolidone and N-vinylcaprolactam give good results. The best results were obtained with 3-allyloxy-1,2-propanediol. The grafting of the compound (a) onto the fluoropolymer (A) can be carried out according to any known method for this purpose. Depending on the chemical properties and the physical state of the compound (a), this grafting can be carried out in the solid state, in solution, in suspension, in an aqueous medium or in an organic solvent. This grafting can also be carried out by irradiation, for example by means of an electron beam or by gamma radiation. The grafting of the compound (a) onto the fluoropolymer (A) is most generally carried out on a molten mixture of the compound and the polymer. It can be operated batchwise, in kneaders, or continuously, in extruders. The grafting reaction of the compound (a) on the fluoropolymer (A) is most often favored and initiated by a radical generator, at least when the group (g) of the compound (a) is not itself a group capable of easily forming free radicals, such as peroxy and azo groups. As a radical generator, it is generally used compounds whose decomposition temperature is between 120 and 350 C and the half-life in this temperature zone, of the order of one minute. The radical generator is preferably an organic peroxide, and more particularly an alkyl or aryl peroxide. Among these, there may be mentioned benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di (t-butyl) peroxide, t-butylcumyl peroxide, 1,3-di (2-t butylperoxy-isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane and 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne. 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane and dicumyl peroxide are particularly preferred. When the compound (a) is grafted onto the fluoropolymer (A) continuously in an extruder, the radical generator and the compound (a) can be introduced in any manner provided that they are introduced from continuously in time and that they are well dispersed in the material in

  -. 10- fusion. The radical generator and the compound (a) can be introduced by spraying, for example by means of a spray-type injector or a vaporizer or by injection into the melt. The introduction of the radical generator and compound (a) via a masterbatch with the fluoropolymer (A) powder or via a masterbatch with a load can also be considered. According to a particularly preferred embodiment, the compound (a) is introduced before the radical generator. By melt reaction is meant for the purposes of the present invention, any reaction in the substantial absence of solvent or diluent and at a temperature at least equal to the melting temperature of the fluoropolymer (A). By extruder is meant any continuous device comprising at least one feed zone and, at its outlet, an evacuation zone preceded by a compression zone, the latter forcing the melt to pass through the zone d 'evacuation. The evacuation zone may further be followed by a granulation device or a device giving the extruded material its final shape. Advantageously, it uses known extruders based on the work of a screw or two screws, which, in the latter case, can cooperate in co- or counter-rotating mode (same direction of rotation or opposite direction of rotation) ). Preferably, the extruder used according to the present invention is arranged in such a way that it successively comprises a feed zone, a melting zone of the material, a homogenization zone, a reaction zone, optionally a zone introduction of additives and a compression-evacuation zone preceded by a degassing zone. Each of these zones has a very specific function and is at a very specific temperature. The function of the feeding zone is to supply the fluoropolymer (A). It is usually at a temperature of less than or equal to 50 C. The purpose of the melting zone of the material is to ensure the melting of the material. The function of the homogenization zone is to homogenize the melt.

  The reaction zone serves to ensure the reaction.

  The temperature in the melting zone and in the homogenization zone of the material is usually greater than or equal to the melting temperature of the fluoropolymer (A). The temperature in the reaction zone is usually greater than or equal to the temperature at which the half-life of the radical generator is less than the residence time of the material in that zone. The additive introduction zone has the function of ensuring the introduction of additives when they are added to the extruder. The temperature of this zone is generally a function of the viscosity of the material and the nature of the added additives. The compression-evacuation zone has the function of compressing the material and ensuring the evacuation thereof. The temperature in the compression-evacuation zone is generally a function of the viscosity of the material to be evacuated.

  The compound (a) is preferably introduced into the extruder before the homogenization zone. The radical generator is preferably introduced into the reaction zone of the extruder. Whatever the grafting method adopted, the amount of compound (a) grafted onto the polymer (A), expressed as the amount of compound (a), is advantageously greater than 0.01% by weight relative to the weight of polymer (A). ), preferably 0.05% by weight or, more preferably, 0.1% by weight. In addition, this amount is advantageously less than or equal to 5.0% by weight, preferably 3.0% e1: better still, 2.0% by weight. The assay is usually performed chemically (titration). Outstanding adhesive properties and exceptionally high thermal stability were observed when the polymer (A) entering the polymer compositions according to the invention was a fluorinated polymer grafted with at least one compound (a) containing group (g), at least one organic group having at least one carbon-carbon bond ethylenically unsaturated and, as groups (fl), at least two alcohol groups. According to the applicant, such fluoropolymers grafted are new products which, as such, constitute another object of the present invention; they are hereinafter referred to as fluoropolymers grafted according to the present invention.

  The fluoropolymers grafted according to the present invention are preferably polymers of vinylidene fluoride. Particularly preferably, they contain more than 50% by weight of monomeric units derived from vinylidene fluoride. Most preferably, they are chosen from homopolymers of vinylidene fluoride and random copolymers of vinylidene fluoride containing 10 to 20% by weight of a fluorinated comonomer chosen from hexafluoropropylene and chlorotrifluoroethylene. The group (g) of the compound (a) of the fluoropolymers grafted according to the present invention is preferably an organic group containing at least one terminal carbon-carbon bond (a, (3) ethylenically unsaturated. among the vinyl, allyl, acryloyloxyalkyl and methacryloyloxyalkyl groups, most preferably it is an allyl group.

  The compound (a) of the fluorinated polymers grafted according to the present invention preferably contains at most four alcohol groups. In a particularly preferred manner, it contains at most three. Most preferably, it contains two and only two. The compound (a) of the fluoropolymers grafted according to the present invention is preferably chosen from aliphatic and cycloaliphatic compounds. In a particularly preferred manner, it is chosen from aliphatic compounds. The compound (a) of the grafted fluoropolymers according to the present invention preferably contains at most three ethylenically unsaturated carbon-carbon bonds. In a particularly preferred manner, it contains at most two. Most preferably, it contains one and only one. Good results have been obtained when the compound (a) of the fluorinated polymers grafted according to the present invention was an alkenediol, in particular when the grafted fluoropolymers in question were chosen from homopolymers of vinylidene fluoride and random copolymers of vinylidene fluoride. containing 10 to 20% by weight of a fluorinated comonomer selected from hexafluoropropylene and chlorotrifluoroethylene. Excellent results have been obtained when the compound (a) of the fluorinated polymers according to the present invention was 3-allyloxy-1,2-propanediol, in particular when the fluoropolymers grafted in question were chosen from homopolymers of vinylidene fluoride and copolymers

  Of vinylidene fluoride containing 10 to 20% by weight of a fluorinated comonomer selected from hexafluoropropylene and chlorotrifluoroethylene. The polymeric compositions according to the invention comprise at least one olefinic polymer (B). For the purposes of the present invention, the term "olefinic polymer" is intended to mean a polymer of which more than 50% by weight of the monomeric units are derived from at least one linear olefin. Preferably more than 60% by weight, and particularly preferably more than 80% by weight, monomer units of the olefinic polymer (B) are derived from at least one linear olefin. By way of examples of linear olefins, mention may be made of linear alpha-monoolefins containing from 2 to 20, preferably from 2 to 12, carbon atoms, such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene and 1-dodecene. Preferred linear alpha-monoolefins are ethylene and propylene. The olefinic polymer (B) may be selected in particular from the homopolymers of the aforementioned olefins and, preferably, from the copolymers of these olefins, in particular the copolymers of ethylene and of propylene, with one another or with one or more comonomers, and than among the mixtures of such polymers. The comonomers may be chosen in particular: from the linear alpha-monoolefins described above; among branched alpha-monoolefins containing from 4 to 12 carbon atoms such as 3-methylbutene, 4-methylpentene, 5-methylhexene; among aryl vinyl monomers such as styrene, alphamethylstyrene, ortho-methoxystyrene; among vinyl esters such as vinyl acetate; from halogenated vinyl and vinylidene monomers such as vinyl chloride, vinylidene chloride; among vinyl alkyl ethers such as vinyl methyl ether, vinyl isobutyl ether; among acrylic monomers such as acrylic and methacrylic acids, methyl acrylate, N, N-dimethylacrylamide, acrylonitrile; among conjugated dienes such as butadiene, isoprene, 1,3-pentadiene; Among non-conjugated dienes such as 1,4-pentadiene, 7-methyl-1,6-octadiene, 5-ethylidene-2-norbornene, bicyclo [2.2.1] oct-2,5-diene . The weight content in units formed from the comonomers in the olefinic polymer (B) is advantageously less than 40% by weight and preferably less than 20% by weight. By the term olefinic polymer (B) is meant both the polymers described above, taken alone, and their mixtures. It may be advantageous for the adhesive properties of the compositions according to the invention that the olefinic polymer (B) is an olefinic elastomer, i.e. it is a polyolefin with elastomeric characteristics. An olefinic elastomer generally satisfies various physical properties defined in ASTM D 1566. Preferably, the olefinic polymer (B) has a glass transition temperature of less than -40 C. It usually further has one or more of the following characteristics: as well as references to US-A-5001205

  a Mooney viscosity (ASTM D 1646) preferably not less than 10, a weight average molecular weight (Mw) preferably not less than a certain value, 10000 in this case; a degree of crystallinity preferably not exceeding 25%. The olefinic polymer (B) is preferably selected from copolymers of at least one first linear alpha-monoolefin selected from ethylene and propylene, and at least one second alpha-monoolefin different from the first, selected from linear alpha-monoolefins containing from 2 to 12 carbon atoms, such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and alpha branched monoolefins containing 4 to 12 carbon atoms, such as 3-methylbutene, 4-methylpentene, 5-methylhexene. The second alpha-monoolefin is preferably selected from ethylene and propylene. Optionally, these copolymers may also contain at least one conjugated diene such as butadiene, isoprene, 1,3-pentadiene or at least one non-conjugated diene such as 1,4-pentadiene, 7-methyl-1 6-octadiene, 5-ethylidene-2-norbornene, bicyclo [2.2.1] oct-2,5-diene. The respective proportions of first and second alpha-monoolefins present in the olefinic polymer (B) can vary widely. They are preferably chosen so that the olefinic polymer (B) has elastomeric characteristics. Thus, the olefinic polymer (B) generally comprises at least 40% by weight, preferably at least 75% by weight of the first alpha-monoolefin, and at least 5% by weight, preferably at least 10% by weight of the second alpha-monoolefin, based on the total weight of the olefinic polymer (B). The amount of first alpha-monoolefin present in the olefinic polymer (B) is generally not greater than 95% by weight, preferably not more than 85% by weight and the amount of second alpha-monoolefin present in the olefinic polymer ( B) is generally not more than 40%, preferably not more than 20% by weight, based on the total weight of the olefinic polymer (B). When the olefinic polymer (B) contains a conjugated or non-conjugated diene, this diene is present in an amount of at least 0.5%, preferably at least 5% by weight, relative to the total weight of the olefinic polymer ( B). The amount of conjugated or non-conjugated diene present in the olefinic polymer (B) is generally not greater than 25, preferably not more than 15% by weight, based on the total weight of the olefinic polymer (B).

  Particularly preferred olefinic elastomers for incorporation as olefinic polymer (B) in the compositions according to the invention - in particular when the latter are intended for the production of multilayer structures, one of the layers to be adhered to is an thermoplastic polymer layer rich in monomeric units derived from propylene - are olefinic elastomers containing from 70 to 95, preferably from 75 to 90% by weight of propylene, and from 5 to 30, preferably from 10 to 25% by weight of 'ethylene. Olefinic elastomers corresponding generally to this composition may advantageously be prepared in the presence of catalyst systems containing complexes based on metallocenes, for example according to the processes described in documents US-B-654088 and US-A-50012051.

  As a corollary, when the compositions according to the invention are intended for the production of multilayer structures in which one of the layers to be adhered is a thermoplastic polymer layer rich in monomer units derived from ethylene, olefinic elastomers which are particularly preferred for being incorporated as olefinic polymer (B) in the compositions according to

  According to the invention, the olefinic elastomers contain from 70 to 95%, preferably from 75 to 90% by weight of ethylene, and from 5 to 30%, preferably from 10 to 25% by weight, of propylene. These can also be advantageously prepared in the presence of the catalytic systems mentioned above.

  According to the invention, the olefinic polymer (B) is grafted with at least one compound (b) containing at least one functional group (f2). Provided that the functional group (f2) is capable of reacting with the group (f1) contained in the compound (a) and also capable of conferring adhesion properties on the olefinic polymer (B), the grouping (f2) and the compound (b) the container, generally meet the same definitions and limitations as those applying respectively to the grouping (fi) and compound (a), mentioned above. In other words, all that has been stated and described above with respect to: the nature of the functional group (fi); the nature of the compound (a) containing this functional group (fi); the nature of the group (g) making it possible to graft said compound (a) onto the fluoropolymer (A); the processes according to which the compound (a) is grafted on the fluoropolymer (A) and their preferred embodiments; is applicable, mutatis mutandis, to the grafting, on the olefinic polymer (B), of the compound (b) containing the functional group (f2). That being said, it will be noted that the group (f2), for the functionalization by grafting of the olefinic polymer (B), is preferably chosen from: (f2.1) groups derived from carboxylic acids (acidic groups); (f2.2) groups derived from carboxylic anhydrides, resulting from the condensation of two carboxylic acid groups in the same molecule (anhydride groups).

  As for the compound (b) containing the group (f2), it is preferred to choose from compounds containing at least one organic group having at least one terminal carbon-carbon bond (a, (3) ethylenically unsaturated as a group making possible the grafting said compound (b) onto the olefinic polymer (B) Examples of such compounds are unsaturated mono- or dicarboxylic acids and their derivatives and monounsaturated or dicarboxylic unsaturated acid anhydrides, such as acrylic acid. 'acid

  Methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, bicyclo [2.2.1] hept-2-ene-5,6 dicarboxylic acid, maleic anhydride, itaconic anhydride, crotonic anhydride and citraconic anhydride. Maleic anhydride is particularly preferred, especially for reasons of accessibility. According to a variant (V 1) of the invention, the acid group and / or the anhydride group that may be present in the compound (b) are not neutralized. According to another variant (V2) of the invention, the acid group and / or the anhydride group that may be present in the compound (b) are neutralized, in whole or in part, with at least one neutralizing agent. This neutralizing agent may be an inorganic salt, an organic salt or a mixture of an organic salt and an inorganic salt. According to (V2), the inorganic salt is preferably an alkali metal carbonate, bicarbonate, phosphate or monohydrogenphosphate. Sodium carbonate is particularly preferred. According to (V2), the organic salt is preferably a carboxylate or a mono- or polyhydroxycarboxylate of a metal, which may be in particular an alkali metal, an alkaline earth metal, a metal of the family IIIa of the periodic table of the elements or a transition metal. In a particularly preferred manner, the organic salt is a carboxylate of a transition metal or an alkali metal mono- or polyhydroxycarboxylate. Most preferably, the organic salt is selected from sodium lactate and zinc acetate.

  According to (V2), the neutralizing agent is used in an amount preferably greater than 0.5 molar equivalent relative to the number of moles of the acid group and / or or anhydride (f2) may be present in the compound (b). Moreover, according to (V2), the neutralizing agent is used in an amount preferably of less than 3 eq.mol. relative to the number of moles of the acidic group and / or or anhydride (f2) may be present in the compound (b). The grafting of the compound (b) onto the olefinic polymer (B) is most generally carried out on a molten mixture of the compound and the polymer. It can be operated batchwise, in kneaders, or continuously, in extruders. Regarding the operational particularities of this mode

-.18-

  grafting, reference is made to the foregoing description of the grafting of the compound (a) on the fluoropolymer (A). Whatever the grafting method chosen, the amount of compound (b) grafted onto the polymer (B), expressed as the amount of compound (b), is advantageously greater than 0.01% by weight relative to the weight of polymer (B). ), preferably 0.02% by weight or, more preferably, 0.03% by weight. In addition, this amount is advantageously less than or equal to 3.0% by weight, preferably 1.5% and more preferably 1.0% by weight. The polymeric compositions according to the invention comprise at least one polymer (C) chosen from polyesters and polyamides. Polyesters are intended to denote polymers in which more than 50% by weight, preferably more than 90% by weight, and particularly preferably all, of the repeating units are free of fluorine atoms and comprise at least one ester group. (-C (= O) -O-). Recurring units are repeating units derived from a single monomer which has reacted according to a ring opening reaction and / or a single monomer which has reacted according to a self-condensation reaction and / or two different monomers which have reacted with each other according to a condensation reaction. The polyesters that can be used as polymer (C) can be in particular any thermoplastic polyester resulting from the melt phase polycondensation, optionally followed by a post-condensation in the solid state, an aromatic or aliphatic dicarboxylic acid or its dimethyl ester on an aliphatic diol, or an aliphatic hydroxy acid on itself or its lactone form.

  Examples of dicarboxylic acids or their dimethyl esters which can be used to prepare these polyesters are terephthalic acid, dimethyl terephthalate, methyl naphthalene dicarboxylate and adipic acid. Examples of aliphatic diols useful for preparing these polyesters are ethylene glycol, propane-1,3-diol and butane-1,4-diol. Examples of polyesters are poly (alkyleneterephthalates), such as poly (ethylene and polybutyleneterephthalates), poly (ethylene naphthalate), poly (butylene adipate) and their copolymers, aliphatic polyesters obtained by polycondensation of Examples of suitable aliphatic hydroxy acids are L- and D-lactic acids (and cyclic lactides resulting from the condensation of two molecules of these) and glycolic acid. Examples of monomers containing such a lactone ring are α-caprolactone, pivalolactone, enantholactone, caprylolactone, polyamides, and polymers of which more than 50% by weight. preferably more than 90% by weight, and most preferably all, recurring units are free of fluorine atom e t comprise at least one amide group (-C (= O) -NH-). The polyamides that may be used as polymer (C) may be any melt-extruded polyamide whose number-average molecular weight is preferably greater than 5000. Among these polyamides, mention may be made of the products of the polycondensation of equimolar amounts of at least one saturated dicarboxylic acid containing 4 to 14 carbon atoms with a primary diamine containing 4 to 14 carbon atoms. Examples of dicarboxylic acids which can be used to prepare these polyamides are adipic, suberic, sebacic, azelaic, malonic, pimelic, isophthalic and terephthalic acids. Examples of primary diamines which can be used to prepare these polyamides are tetramethylenediamine, pentamethylenediamine, hexamethylenediamine and octamethylenediamine. Examples of polyamides are poly (hexamethylene adipamide) (nylon 66), poly (hexamethylene azelaamide) (nylon 69), poly (hexamethylene sebacamide) (nylon 610), poly (hexamethylene dodecanoamide) (nylon 612), nylon poly (dodecamethylene dodecanoamide) (nylon 1212) and their copolymers. The products of the polycondensation of lactams and amino acids are also usable. Among these products, mention may be made of polycaprolactam (nylon 6), polycaproamide and poly (11-aminoundecanoamide). The polymer (C) is preferably chosen from aliphatic polyesters and aliphatic polyamides. The term "aliphatic polyesters" is intended to denote polymers in which more than 50% by weight, preferably more than 90% by weight, and particularly preferably all, of the repeating units are aliphatic, devoid of fluorine atom and comprise at least an ester group (-C (= O) -O-). These recurring units are usually the product of the condensation reaction of an aliphatic diacid (and / or its dimethyl ester) and

  An aliphatic diol, and / or a self-condensation of an aliphatic hydroxy acid, and / or a ring opening of a lactone. The term "aliphatic polyamides" is intended to denote polymers in which more than 50% by weight, preferably more than 90% by weight, and particularly preferably all, of the repeating units are aliphatic, devoid of fluorine atom and comprise at least an amide group (-C (= O) -NH-). These recurring units are usually the product of the condensation reaction of an aliphatic diacid (and / or its dimethyl ester) and an aliphatic diamine, and / or self-condensation of an aliphatic amino acid, and or of ring opening of a lactam. In a particularly preferred manner, the polymer (C) is an aliphatic polyester. Most preferably, the polymer (C) is an aliphatic polyester of which more than 50% by weight, preferably more than 90% by weight, and most preferably all of the repeating units are derived from at least one lactone. Most preferably, the polymer (C) is a polycaprolactone, i.e. an aliphatic polyester of which 50% by weight, preferably more than 90% by weight, and most preferably all, recurring units are derived from ε-caprolactone. The polymer (C) has a weight average molecular weight advantageously of at least 10,000, preferably at least 50,000, and particularly preferably at least 70,000. Moreover, the weight average molecular weight of the polymer ( C) is advantageously less than 100,000.

  The respective proportions in which the fluoropolymer (A), in its grafted form, and the olefinic polymer (B), in its grafted form, are present in the compositions according to the invention may vary to a large extent, depending in particular respective contents of compound (a) and compound (b) respectively grafted on said fluoropolymer and said olefinic polymer. In general, these proportions are such that the ratio by weight of the fluoropolymer (A) to the olefinic polymer (B) [(A): (B)] is between 10: 90 and 90: 10. Preferably, the weight ratio [(A): (B)] is from 35:65 to 65:35. The best results have been obtained when the weight of fluoropolymer (A) exceeds at least about 25% and at most about 50%. the weight of olefinic polymer (B) in the composition according to the invention,

  That is, when the weight ratio [(A): (B)] is from about 55:45 to about 60:40. The amount of polymer (C) present in the polymeric compositions according to the invention is generally not greater than that of the fluorinated polymer (A) and the olefinic polymer (B). In general, the polymer (C) is present in the polymer compositions according to the invention in a proportion of 5 to 35% by weight relative to the total weight of the latter, preferably in a proportion of 10 to 30% by weight, more particularly at 18 to 28% by weight. Most preferably, the polymeric compositions according to the invention comprise from 35 to 45% by weight of the fluoropolymer (A), from 30 to 40% by weight of olefinic polymer (B) and from 20 to 30% of polymer. (VS). The polymeric compositions according to the invention may furthermore comprise one or more usual additives for thermoplastic polymers, such as, for example, acid scavengers, lubricating agents, organic or inorganic dyes, nucleating agents, filler materials, stabilizing agents and flame retardants. The polymeric compositions according to the invention can be prepared by any known method. Advantageously, one will choose a method ensuring an intimate mixture of their constituents (A), (B) and (C).

  Advantageously, in addition, a method will be chosen which allows at least the partial reaction of the functional group (f 1) of the compound (a) with the functional group (f 2) of the compound (b). Another aspect of the invention therefore relates to a method for producing the compositions as described above, wherein the melt-mixed fluorinated polymer (A), the olefinic polymer (B) and the polymer (C). In the method according to the present invention, it is furthermore preferred to melt react the fluoropolymer (A), the olefinic polymer (B) and the polymer (C). Thus, for example, in the method according to the present invention, the constituents (A), (B) and (C) can first be premixed dry, in the required proportions, in any device suitable for this purpose, such as a drum mixer. The dry premix thus obtained is then melted either batchwise, in discontinuous devices, such as kneaders, or in continuous devices, such as the extruders described above in connection with the grafting of the compound (a) on the polymer. fluorinated (A). It is also possible to carry out the premixing intended to be melted by the masterbatch technique. We can

  Feed the mixers or extruders by the components (A), (B) and (C) metered separately without premixing dry. It may be advantageous, especially when the component (B) is an olefinic elastomer, to add to the constituents (A), (B) and (C) a few percent by weight, generally between 1 and 20%, preferably between 2 and 10% by weight of a processing aid which may for example be a low density polyethylene. Once the constituents (A), (B) and (C) are melted, the mixing of these constituents is carried out or continued in any suitable device for this purpose. Advantageously, the same discontinuous devices (kneaders, for example) or continuous devices (extruders, for example) as those previously used for the melting operation are used for this purpose. Finally, while continuing the melt blending of the components (A), (B) and (C) or after completing it, the constituents (A), (B) and (C) are preferably reacted en masse. melted in these same devices. Those skilled in the art can easily determine the general operating conditions of the mixing, melting and reaction devices by means of some preliminary routine tests. In the case of extruders, in particular, the temperatures of the melting, homogenization and reaction zones are generally set between 140 and 270 ° C., preferably between 170 ° and 240 ° C. the pressure in the die is generally less than 200 bar, preferably 100 bar, and more preferably still 50 bar, the rotational speed of the screw or screws is generally between 50 and 2000 revolutions per minute, preferably between 200 and 1000 rpm. The adhesive properties of the compositions according to the invention can be exploited for the production of multilayer structures, which constitute another object of the present invention. These are multilayer structures, one of whose layers consists of the polymeric composition with adhesive properties. These structures contain at least one other layer that can be made of various materials, both inorganic and organic. As inorganic materials that may be included in the composition of this other layer, mention may be made of metals and metal alloys, such as aluminum and steel, for example. As organic materials that may be included in the composition of this other layer, mention may be made of thermoplastic polymers. Examples of thermoplastic polymers which may be included in the composition of this other layer are the fluorine-containing polymers belonging to the family of fluorinated polymers (A) and the polymers containing olefins of the same nature as those present in the olefinic polymer (B).

  Particular multilayer structures according to this aspect of the present invention are three-layer structures with X / Y / Z configuration, the central layer Y of which consists of the polymeric composition with adhesive properties according to the invention and whose X and Y layers. are made of a thermoplastic polymer, as defined above. Preferred multilayer structures are three-layer structures X / Y / Z configuration of which the central layer Y consists of the polymer composition with adhesive properties according to the invention, the layer X consists of an olefin-based polymer (s) ) of the same nature as that (s) present in the olefinic polymer (B) and the Y layer consists of a polymer meeting the definition of fluoropolymers (A). These multilayer structures can be produced by any method known for this purpose and compatible with the nature of the constituent material of each layer. The assembling of the layers can be done for example by gluing or by hot pressing the constituent layers together, by coating a solid layer with a powder or a solution of the material constituting the one or the other ( s) layer (s); or again, in particular in the case where the materials constituting the layers are thermoplastic polymers, by coextrusion, coextrusion-blow, coinjection and coinjection-molding. Coextrusion is particularly suitable for the production of multilayer structures X / Y / Z configuration whose central layer Y consists of the polymer composition with adhesive properties according to the invention, the outer layer X consists of a polymer with olefin base (s) of the same nature as that (s) present in the olefinic polymer (B), in particular a homo- or copolymer derived from ethylene and / or propylene and the layer Y, interior, consists of a polymer meeting the definition of fluorinated polymers (A), in particular a homo- or copolymer derived from vinylidene fluoride. This coextrusion can be carried out for example in three extruders, preferably three single-screw extruders, feeding a flat die via a feed-block or, preferably, supplying three-layer tubular dies. The multilayer structures thus produced can be manufactured in the final form of sheets, films, tanks, bottles, containers, tubes and pipes, particularly tubes, pipes and reservoirs.

  • 24 - transport and storage of liquid hydrocarbons, particularly oils and fuels. The following examples are intended to illustrate the invention without limiting its scope.

  EXAMPLE 1 In a Brabender Plasticorder PL 2000 mixer running at 50 rpm, a polymer composition was prepared by mixing with each other, at a temperature of 200 ° C: (A) a random copolymer containing 85% by weight of fluoride of vinylidene and 15% by weight of hexafluoropropylene, whose melt index MFI2.l6kg, 230 C (ASTM standard 1238) is 8 g / 10min and which has been grafted with 3-allyloxy-1,2-propanediol molecules (This graft copolymer was obtained by using, in a Clextral model BC 21 twin-screw corotative extruder whose feed zone was heated to 170 ° C. and the extrusion die at 220 ° C., per kg of extruded copolymer. 15 g of allyl glycidyl ether and 4 g of 2,5-dimethyl 2,5-di (tert-butylperoxy) hexane (DHBP) as a radical generator); (B) an olefinic elastomer containing 80% by weight of propylene and 20% by weight of ethylene, whose melt index MFI216kg, 2300c (ASTM 1238 standard) is 2.3 g / 10min, the Mooney viscosity ( ASTM D 1646 is 25 (a product sold by Exxon Mobil Chemical under the name Vistamaxx VM 1100) which has been conventionally grafted with maleic anhydride in the presence of DHBP as a radical generator (C). a polycaprolactone having a weight average molecular weight of 80000 and a melt index MFI2.16kg, 160 ° C. of 3 g / 10 min (product sold under the name Capa 6800 by Solvay). weight of the polymeric composition, component (B) 30% by weight and component (C) 25% by weight In a Werner & Pfleiderer hydraulic press, whose mold consists of 180 mm x 180 mm x steel plates 2 mm coated with a non-stick Teflon film, produces a three-layer structure whose central layer consists of the polymer composition prepared as indicated above, the upper layer consists of a random copolymer of propylene and ethylene marketed under the name ELTEX P KS 409 by

  BP North America (melt flow rate MFI 216 kg, 230 ° C. (ASTM 1238 standard): g / 10 min) consists of an olefin polymer and the lower layer consists of the fluoropolymer mentioned under (A) above. above, but not grafted. For the production of the three-layer structure, the press is kept for 10 minutes at atmospheric pressure and then for 2 minutes at 50 bar; then press the press for 5 minutes at room temperature to 20 bar. A manual peel test shows that it is impossible to dissociate the constituent layers of the three-layer structure obtained, even when pulling at full strength.

  Example 2R This example is provided for comparison. Example 1 is repeated except that polycaprolactone (C) is not used for the preparation of the polymeric composition. In the peel test, the bottom layer made of the fluoropolymer peels off easily from the trilayer structure. Example 3R This example is provided for comparison. Example 1 is repeated except that the constituents (A) and (B) of the polymeric composition are not grafted. In the peel test, the bottom layer consisting of the fluoropolymer peels off easily from the trilayer structure. Example 4R This example is provided for comparison. Example 1 is repeated except that component (B) of the polymeric composition is not grafted. In the peel test, the bottom layer consisting of the fluoropolymer peels off easily from the trilayer structure. Example 5 A component (A) was prepared as in Example 1 except that the random copolymer containing 85% by weight of vinylidene fluoride and 15% by weight of hexafluoropropylene was grafted with allyl glycidyl ether instead of 3-allyloxy-1,2-propanediol. The thermal stability of the constituents (A) of Example 1 (grafted 3-allyloxy-1,2-propanediol (AOPD)), Example 3R (non-grafted PVDF) and the present Example (grafted PVDF) were compared. allyl glycidyl ether (AGE)) by thermogravimetric analysis. The following results were obtained: Temperature at which a weight loss of x% is obtained (C) Sample x = 1% x = 2% x = 3% x = 5% x = 10% Polymer (A) of Example 365 C 378 C 386 C 397 C 414 C 3 R - PVDF ungrafted Polymer (A) of Example 5 - 369 C 387 C 393 C 403 C 418 C PVDF grafted AGE Polymer (A) of Example AOPD-grafted PVDF The polymer (A) of Example 1 (AOPD grafted PVDF) was observed to have a thermal stability well above that of the polymer (A) of the present invention. Example 5 (grafted PVDF AGE), itself much greater than that of the polymer (A) of Example 3R (ungrafted PVDF). This excellent thermal stability of the AOPD-grafted PVDF is one of the advantages that makes the use of this polymer particularly attractive in the adhesive polymer compositions according to the present invention.

Claims (8)

  1 - fluorinated graft polymers of at least one compound (a) containing at least one organic group (g) having at least one carbon-carbon bond ethylenically unsaturated and at least two alcohol groups.   2 - Polymers according to claim 1, characterized in that they are polymers of vinylidene fluoride.   3 - Polymers according to claim 1 or 2, characterized in that the group (g) is chosen from vinyl, allyl, acryloyloxyalkyl and methacryloyloxyalkyl groups.   4 - Polymers according to any one of claims 1 to 3, characterized in that the compound (a) contains at most three alcohol groups.   5 - Polymers according to any one of claims 1 to 4, characterized in that the compound (a) is chosen from aliphatic compounds.   6 - Polymers according to any one of claims 1 to 5, characterized in that the compound (a) contains one and only one carbon-carbon bond ethylenically unsaturated.   7 - Polymers according to any one of claims 1 to 6, characterized in that the compound (a) is an alkeniol.   8 - Polymers according to claim 7, characterized in that the compound (a) is 3-allyloxy-1,2-propanediol.